When analysed along weight status lines, a discordant relationship was found between the sexes. Overall, the relationship between blood pressure and measures of obesity is not linear throughout the BP spectrum. Clearly the said relationship is not a ‘straitjacket affair’.Obesity is known to correlate with measures of blood pressure (BP). The nature of the correlations has, however, remained a subject of scientific enquiry, especially when BP phenotypes are disaggregated and obesity is determined by a variety of methods. This study examined the relationship between obesity and BP in young-adult Nigerians. A total of 1610 subjects  were recruited from five universities in the Igbo-speaking part of Nigeria. Relevant BP and anthropometric data were obtained following standard protocols. Appropriate statistical tools were used for data analyses. The results show that 42.2%  and 13.3%  of the population had point prehypertension and hypertension, respectively. By body mass index (BMI) standards, 20.6%  of the population were overweight/obese. Despite the weak positive and significant correlations between BP and the measures of obesity in both males and females in the general population ( The relationship between obesity and elevations in blood pressure (BP) has recently been the subject of renewed scientific interest. Classical scientific thought proposes that weight gain ultimately leads to elevated blood pressures that, when sustained, results in hypertension . This isConversely, there are reports of a ‘plateau’ or ‘hyperbole’ observed when the blood pressure versus body mass index (BMI) curve is split along blood pressure phenotypes ,5,6. TheBecause the BMI is fraught with challenges, such as its inability to distinguish between muscle mass and adipose tissues, which makes its use in studying metabolic disorders difficult , it becaThis study therefore tested the hypothesis that the plateau effect of high blood pressure on the blood pressure versus body mass index curves of adults exists independent of the measure of obesity in question. The results will hopefully broaden the understanding of the complex interrelationships between the two major contributors to cardiovascular disease—hypertension and obesity.Five tertiary institutions in the five Southeastern States of Nigeria (one per State) were randomly selected for this cross-sectional study. The institutions are Ebonyi State University, Abakaliki, Imo State University, Owerri, University of Nigeria, Nsukka, Michael Okpara University of Agriculture, Umudike, and Anambra State University, Uli. Students attending these institutions of higher learning, aged 18 to 30, who gave informed verbal consent were recruited for the study. Pregnant or lactating women and subjects with any form of physical disability and/or overt or reported illness were excluded from the study. Ethical approval for this study was obtained from the Ethics Committee of the Federal Medical Centre, Umuahia on the 13th of June, 2014.For each of the five institutions, 330 students who met the inclusion criteria were recruited. In each institution, subjects were purposively sampled to ensure that students from as many Colleges/Faculties and Departments were recruited. A total of 1610 subjects  out of the 1650 subjects recruited were eventually studied. Forty subjects had incomplete data entries and were excluded from the analyses.2].Self-reported age at last birthday was recorded per subject. Heights of the subjects were measured with an inelastic vertical measuring rod to the nearest 0.1 cm. The subjects were required to stand on bare feet for all height measurements. For weight measurements, the subjects were required to be on bare feet and wearing light clothing, while a calibrated electronic bathroom scale  was used. Weight measurements were made to the nearest 0.1 kg. The waist circumference (WC) of each subject was measured using a non-elastic fibre glass tape to the nearest 0.1 cm. The tape was snugly placed in a horizontal plane  round the abdomen, at the midpoint between the top of the iliac crest (just below the navel) and the lower margin of the last palpable rib in the mid axillary line. The hip circumference (HC) of each participant was measured at the widest circumference over the buttocks using a non-elastic measuring tape to the nearest 0.1 cm. From these measurements, waist-to-hip ratio (WHpR) was calculated as WC/HC; waist-to-height ratio (WHtR) was calculated as WC/Height; and BMI was calculated as weight (kg)/ [29.5% (95% CI: 24.8 to 34.3) for men and 25.0% (95% CI: 20.2 to 29.7) for women] . The secThe large proportion of prehypertensive subjects reported here is however worrisome as they may eventually become hypertensive, especially with age. It is, however, plausible that the prevalence of both hypertension and prehypertension reported here may be related to ‘white coat’ hypertension as the subjects were largely naïve to blood pressure measurement. We found that there was a clear male preponderance of (pre)hypertension in the population. Akin to our findings, both systematic reviews ,17 mentiObesity is reported to be a significant risk factor for hypertension . Though The relationship between hypertension and obesity remains a subject of scientific controversy. While most authors agree that both disorders are correlated, the nature of such correlation is a matter of far less consensus . In thisThe implication of the observed ‘plateau effect’, especially among the males, is that the response of blood pressure to increases in obesity is not linear along the blood pressure or obesity continuum. The paradox of secular decreases in blood pressure, despite increasing obesity prevalence in economically developed societies, has been explained by suggestions that changes in dietary intake and/or exercise could influence BP through mechanisms not directly related to weight loss ,24. BunkThis study is limited by the use of an oscillometric device instead of the standard auscultation protocol. The device used here, however, has been validated in, and used extensively for, similar populations as the one studied. Secondly, blood pressures were measured on a single visit such that only point (pre)hypertension could be determined. The nature of this study and the limited resources at our disposal, however, were insurmountable constraints. Finally, the low levels of obesity and to some extent hypertension in the studied population may have made it difficult to appreciate the relationships studied here better. Subsequent studies should deliberately/purposively seek to recruit more overweight/obese and hypertensive subjects. The spread of our sampling and the depth of our analysis, however, are strengths of this study.This study tested the hypothesis that the plateau effect of high blood pressure on the blood pressure versus body mass index curves of young adults exists independently of the measure of obesity in question. The results provide evidence for the hypothesis to be accepted. The relationship between blood pressure and measures of obesity is clearly not a ‘straitjacket affair’.


Visual loss is a devastating perioperative complication that can result from elevated intraocular pressure (IOP). The Trendelenburg position during surgery increases IOP. The purpose of this study was to quantify IOP changes in patients undergoing laparoscopic hysterectomy, at different time points and body positions throughout the procedure, and to compare fluctuations of IOP during the perioperative period according to two fluid management protocols. 2, and ocular perfusion pressure were assessed prior, during, and postsurgery, at 8 time points altogether.  Thirty women scheduled to undergo elective gynecologic laparoscopic pelvic surgery were randomly allocated to receive a liberal or restrictive fluid management protocol. IOP, mean arterial pressure, heart rate, exhaled tidal volume, end-tidal CO Mean changes in IOP were similar for the two protocols; the peak IOP was at the steep (peak) Trendelenburg position. For each protocol, IOP correlated positively with mean arterial pressure, and mean blood pressure correlated with ocular perfusion pressure.  IOP was elevated during laparoscopic pelvic surgery and particularly at the steep Trendelenburg position. No differences were found in any of the parameters examined according to a liberal or restrictive fluid management protocol. Visual loss is a devastating perioperative complication with an estimated incidence of 0.01–1%, depending on the type of surgery . Among t003-12-ZIV at the Israeli Ministry of Health.Laparoscopic surgery is associated with several physiological changes that tend to increase IOP . As for The study comprised 30 consecutive women who were scheduled for elective gynecologic laparoscopic pelvic surgery between January 1, 2015, and December 31, 2015, and who met study inclusion criteria. The exclusion criteria were age older than 70 years or less than 18 years, body weight > 150% of the ideal body weight, acute or chronic eye disease, use of any medication known to alter IOP, patients not capable or willing to sign informed consent. The study was approved by Helsinki Committee of Ziv Medical Center, and written informed consent was obtained from all patients prior to surgery.2 at 35–40 mmHg throughout the procedure. Pneumoperitoneum was created by intraperitoneal insufflation of CO2, with the patient in the supine position. Throughout the surgery, intraperitoneal pressure was maintained automatically at 14 mm Hg by a CO2 insufflator.Participants were alternately allocated to two equal groups (15 patients each), to receive either a liberal or restrictive fluid management protocol , based o2, entropy values, IOP and OPP, were recorded at the following time points: T1—before the induction of anesthesia; T2—after the induction of anesthesia, in a supine and horizontal position, mechanically ventilated, before pneumoperitoneum; T3—after the pneumoperitoneum was established; T4—while the pneumoperitoneum was established, with a 15°–20° head-down tilt; T5—while the pneumoperitoneum was established, steep (peak) Trendelenburg position; T6—after the pneumoperitoneum was evacuated in the horizontal position; T7—in the recovery room, 30 degrees head up, 30 min after tracheal extubation; and T8—on the first postoperative day. Since blood pressure affects IOP, we examined the relationship between MAP and IOP at various concentrations of fluid intake in both study groups.IOP was measured using a Tono-pen® XL by a trained ophthalmologist who was unaware of the perioperative fluid administration regimen. Measurements were repeated if the variability between sequential measurements exceeded 5%. Two sets of measurements for each eye were collected . All measurements were performed by the same team of ophthalmologists. The depth of anesthesia was continuously evaluated with an entropy monitor. MAP, heart rate (HR), exhaled tidal volume, ET CO2 with the patient in the supine position. Throughout the surgery, intraperitoneal pressure was maintained automatically at 14 mm Hg by a CO2 insufflator.After each change in position and intraperitoneal pressure, a 5-minute period was allowed for stabilization before measurements were performed. Pneumoperitoneum was created by intraperitoneal insufflation of COt-test for the independent groups was used to examine the difference of IOP between the two treatments . Pearson's correlation was used to calculate correlations between the continuous variables and chi-square correlation between categorical variables. Values at p < 0.05 were considered statistically significant. The study was approved by the local bioethical committee of Ziv Medical Center, Israel.The p < 0.0001; data for all 30 patients). Subsequently, a far greater increase in IOP was observed during and immediately following Trendelenburg positioning . The peak IOP for both protocols was when pneumoperitoneum was established and the position was the steep (peak) Trendelenburg position (T5). On the first postoperative day (T8), the mean IOP for both groups was approximately equal to the mean preanesthetic IOP (T1). For both fluid management groups, the relationship between IOP and MAP did not change at different fluid intakes. Considering the data of all 30 participants, IOP correlated positively with MAP  similar IOP measurements between patients who were treated with different preoperative fluid management protocols; (2) reduction in IOP following the induction of anesthesia in a supine and horizontal position and while patients were mechanically ventilated; (3) significant elevation of IOP during pneumoperitoneum and specifically in the steep Trendelenburg position; and 4) normal levels of IOP at about 12 hours postsurgery, similar to levels measured prior to the operation. Elevation of IOP may be problematic in patients who undergo gynecologic laparoscopic pelvic surgery and who also have chronic simple glaucoma. For patients with progressive damage to the optic disc, elevated IOP may exacerbate the injury to the retinal nerve fiber layer (RNFL) and further impair the visual field. In such patients, we suggest that a thorough ophthalmic examination, including a visual field test, the measurement of RNFL thickness and IOP, should be done prior to the gynecologic laparoscopic pelvic surgery. In extreme cases, gynecologists should consider another surgical approach, since, as shown in our study, the elevation of IOP in these surgeries is significant and the relatively long operating time raises the risk of damage to the RNFL. For measuring IOP, we used the Tono-pen due to its speed, ability to make measurements on multiple patients, ease of use including disposable latex tip covers, accuracy in a variety of positions,  reliabil normal lPneumoperitoneum, and specifically the steep Trendelenburg position, during gynecologic laparoscopic pelvic surgery may induce a significant elevation of IOP. This elevation was shown not to differ according to the protocol for perioperative fluid management. Surgeons who conduct such operations should consider this risk, especially in patients who already have glaucoma. Further studies are required to establish our findings.


BP) is common in acute ischemic stroke, but its effect on outcome is not fully understood. We aimed to investigate the association of baseline BP and BP change within the first day after stroke with stroke severity, functional outcome, and mortality.Elevated blood pressure  from 15 February 2005 through 31 May 2009 were consecutively included. Acute stroke severity and functional outcome at three and twelve months were investigated using multivariate regression analysis; the association between SBP and ΔMAP) were associated with decreased 1‐month mortality , 3‐month mortality , and twelve‐month mortality . Stroke severity was associated with ΔMAP . Higher SBP and MAP on admission were associated with better functional outcome at three  and twelve  months.A total of 799 patients  were included. Higher decreases in systolic and mean arterial blood pressure  and decrease in BP after the patients’ arrival to the ward were associated with improved functional outcome and reduced mortality, respectively. These results may reflect a regulatory situation in which elevated initial blood pressure indicates adequate response to cerebral tissue ischemia while subsequent blood pressure decrease instead may be a consequence of partial, successful reperfusion.In this elderly population, higher  The neurological department also treated patients who underwent thrombectomy or received thrombolytic therapy. Thus, younger stroke patients and patients who received more invasive therapy were not included in our material. Patient demographics and clinical history were collected consecutively and recorded in a database. The study was approved by the Regional Ethical Review Board in Gothenburg.2.2Standardized forms were used to obtain relevant medical history data from patients via interview or collected from medical records. When a patient was unable to answer for him or herself, a knowledgeable proxy was interviewed instead.Preexisting conditions, for example, hypertension, were considered present if patients, proxies, or medical records reported them as such or if the patients were treated with drugs targeting the condition . The same principle was applied for diabetes mellitus, atrial fibrillation, previous stroke, myocardial infarction, and congestive heart failure.Standard techniques were utilized for laboratory analyses. Computed tomography scans were performed on admission. Stroke diagnosis was assessed in accordance with the World Health Organization's definition .The severity of the stroke was defined at the ward using the National Institutes of Health Stroke Scale (NIHSS) by specially trained personnel , and subsequently on arrival to the ward, the latter measurement occurring no later than 12 hr after admission to the ER. Systolic and diastolic BPs were measured in the right arm, in a supine position. If, however, the right arm was afflicted by palsy, pressures were measured in the left arm. BPs were measured on admittance to the ward and on days 1, 2, 3, 7, and at discharge. At the time of the study, local guidelines mandated acute lowering of blood pressure with antihypertensive therapy in patients with IS when BP was ≥220 mmHg.Blood pressure values are presented in the form of systolic, diastolic, and MAP. The MAP values were obtained from SBP and diastolic BP (DBP) values through the following equation: MAP = (SBP*1/3) + (DBP*2/3). Difference in SBP values (ΔSBP) was defined as the SBP value on arrival to the ward, subtracted from the SBP value on arrival to the ER. The same principle was applied for calculating ΔMAP. DBP was not included independently in our analyses because previous work suggests that SBP is a better predictor of events in elderly patients  and all‐cause mortality during the acute phase, at three, and at twelve months. A secondary endpoint was functional outcome, measured by modified Rankin Scale (mRS), at three and 12 months, respectively.2.4The associations between BP values and mortality and functional outcome were investigated using Cox proportional hazard regression and binary logistic regression, respectively. In both analyses, age, sex, NIHSS score in the acute setting, congestive heart failure, diabetes mellitus (type 1 and type 2), and history of IS were used as covariates. In the analyses involving ΔSBP and ΔMAP, SBP and MAP, respectively, were also included as covariates. For the binary logistic regression, values for mRS were categorized into a dichotomous variable, in which a score of 0‐2 was considered a positive outcome and a score of 3‐5 was considered a negative outcome. Patients with mRS scores of 6, which equals death, were excluded from the analysis.For the analysis of associations between BP values and NIHSS score in the acute setting, linear regression was used. In this analysis, age, sex, and history of IS were used as covariates.p‐values <.05.We also performed a separate regression analyses for positive and negative ΔBP values, respectively, to further clarify the significance of increases or decreases in BP, and the covariates were the same as in the Cox proportional hazard regression mentioned above. All statistical analyses were performed with the software IBM SPSS Statistics, version 24 . Results were considered statistically significant if 33.1In total, 799 patients were included. Demographic data, medical history, baseline BP, and laboratory values are presented in Table 3.23.2.1All in all, 70 patients had died at 1‐month follow‐up. Both ΔSBP and ΔMAP displayed significant association with short‐term mortality whereby BP decrease on arrival to the ward was associated with lower mortality. Data are displayed in Table 3.2.2p‐value .01).In linear regression analysis, stroke severity, as measured by NIHSS, was associated with ΔMAP  and 157 (20%) patients had died at 3‐month and twelve‐month follow‐up, respectively. We found a significant association between ΔBP and mortality at both three and twelve months. Decrease in BP, both in the form of SBP and in the form of MAP, was thus associated with lower mortality rates. Data are shown in Table % and 1573.3.2There was a significant association between SBP on admission and functional outcome at both three and twelve months, suggesting that higher initial SBP is linked to better long‐term functional outcome. Data are shown in Table 4Our results thus demonstrate that a decrease in BP, as measured by a drop in either SBP or MAP when comparing BP on arrival to the ER to BP on arrival to the ward, is associated with reduced mortality. The correlation between BP decrease (ΔSBP and ΔMAP) and mortality was significant in both short‐term and long‐term mortality analyses.We also show that a higher admittance SBP or MAP level, measured on arrival to the ER, is significantly associated with better long‐term functional outcome.The mean age of our patients was considerably higher than in previous studies, and we therefore believe our data shed some light on the importance of BP in the acute setting in this older and thus previously unstudied cohort.t test data not shown), our heart failure patients had significantly lower blood pressure than patients without CHF. The inclusion of CHF as a covariate in our regression analyses might thus explain why we did not see an association between lower blood pressure and mortality.We found no significant association between BP on arrival and mortality, neither short‐term nor long‐term. Unlike Wohlfahrt et al. , howeverOur findings, thus, suggest a protective effect of larger BP decreases as well as higher admission BP, where larger BP decrease is associated with lower mortality and higher admission BP is associated with better functional outcome. These findings are in line with the hypothesis that BP elevation in stroke is a physiological, beneficial response to increased demands of perfusion  and a systematic, consecutive, and unbiased patient inclusion method.One strength of our study is excellent follow‐up data, in part due to reliable census data for mortality, but also comprising mRS values for 98% and 92% of patients at three and twelve months, respectively. As mentioned, our study also establishes that BP in the acute setting is an important factor in an older patient cohort (mean age 78 years). Another strength is the reasonably large patient sample (In conclusion, our study shows that a greater decrease in BP on the patients’ admission to the ward and higher BP on arrival to the emergency room is associated with reduced mortality and improved functional outcome, respectively. Conversely, increases in MAP are a predictor of increased long‐term mortality. These results may reflect a regulatory situation in which elevated initial BP indicates adequate response to cerebral tissue ischemia while greater subsequent BP decrease may be a consequence of relatively successful reperfusion.The authors declare no conflict of interest.


Endothelial dysfunction is an important precursor to the development of atherosclerosis, and has been suggested to play a role in the increased cardiovascular risk in patients with end stage renal disease. Endothelial function improves rapidly following post kidney transplantation, but the long term change remains unclear. Hypothesizing that endothelial function would remain improved long term post kidney transplantation, we evaluated the longitudinal change of endothelial function, measured by flow-mediated dilation (FMD) of the brachial artery, from months 1 to 24 post transplantation. Given the previously reported association of fibroblast growth factor 23 (FGF-23) with endothelial dysfunction, we also examined changes in the association between FGF-23 levels and the change in FMD following kidney transplantation.We performed a prospective cohort study of 149 kidney transplant recipients, measuring endothelial function by FMD at months 1, 12, and 24 post-transplant. FGF-23 levels were measured at months 1 and 24 post-transplant. Linear mixed effects models were used to assess both the unadjusted and adjusted outcomes.P = 0.262) or 24 months . FGF-23 decreased significantly over time (P = 0.024), but there was no significant association between FGF-23 and FMD (P = 0.799).The cohort (mean age 49 ± 13 years) was 74 % male and 75 % white. The median FMD was 6.3 % , 5.4 % , and 5.6 %  at 1, 12, and 24 months, respectively. After adjustment for covariates, compared to month 1, no change occurred in FMD at 12 months (−0.66 %; 95 % CI: −1.81 %, 0.49 %; Endothelial function remained stable at 12 and 24 months from 1 month post-kidney transplant, indicating that the improved endothelial function seen with transplant is maintained up to 2 years post transplantation. There was also no significant association between FGF-23 and endothelial function following kidney transplantation. Patients with end stage renal disease (ESRD) requiring maintenance dialysis experience a high incidence and prevalence of cardiovascular disease, which is consequently a leading cause of mortality in this patient population . SuccessOne marker of increased cardiovascular risk is impairment of endothelial function, which is an important precursor to the development of atherosclerosis. Impaired brachial artery endothelial function serves as a marker of underlying atherosclerotic risk and is a reliable surrogate for coronary endothelial function . SeveralA high concentration of circulating Fibroblast Growth Factor 23 (FGF-23) is also an independent risk factor for kidney disease progression, cardiovascular disease and mortality –21. FibrOur aim was to evaluate endothelial dysfunction longitudinally, as measured by flow-mediated dilation (FMD), in a cohort of medically stable, kidney transplant recipients starting at 1 month post transplantation. In addition, we evaluated FGF-23 concentration following transplant to investigate a possible association between FGF-23 levels and changes in endothelial function. We hypothesized that long-term endothelial function would remain improved following successful kidney transplantation, and the longitudinal reduction in FGF-23 levels in the setting of a functioning allograft would be associated with improved endothelial function.We conducted a single-center, prospective cohort study. De novo kidney transplant recipients were recruited from the Vanderbilt University Medical Center (VUMC) Renal Transplant Clinic from August 2009 through May 2013. Inclusion criteria included patients aged ≥ 18 years who were undergoing or had recently undergone kidney transplantation. There were no exclusion criteria. Consent for participation in the study was obtained prior to discharge from the hospital following kidney transplant. Given the widely dispersed geographic area of patients on the kidney transplant waiting list at VUMC, obtaining a baseline FMD measurement prior to kidney transplantation was not logistically practical, thus patients were first evaluated at 1 month following kidney transplantation. Additional follow up visits were performed at 12 and 24 months. All patients gave informed consent and the VUMC Institutional Review Board approved the study protocol.A single, licensed sonographer blinded to clinical details and previous FMD measurements of the study participants obtained the ultrasound images and performed the FMD study. The initial FMD was measured at 1 month following transplant. Follow up FMD examinations were performed at 12 and 24 months.. A pneumatic tourniquet was inflated around the lower arm distal to the site at which the baseline brachial artery diameter was measured. The tourniquet was inflated to 250 mmHg for a total time of 5 min. Reactive hyperemia was measured after restoration of blood flow following the release of the pneumatic blood pressure cuff. Brachial artery diameter was measured at 60 s and 90 s following the release of the blood pressure cuff. Arterial diameter was measured from the media-adventitia interface.Flow-mediated dilation was performed as originally described by Celermajer and colleagues . EndotheThe FMD studies were evaluated by one reviewer (CK) for consistency and accuracy of the brachial artery diameter measurements at the 60 and 90 s time points following the induction of hyperemia after the deflation of the pneumatic tourniquet.Endothelium-dependent FMD was expressed as the percentage change of the brachial artery diameter from baseline to the diameter following reactive hyperemia (Post-test diameter-Baseline diameter)/Baseline diameter). The larger percent change of the two time points measured (60 or 90 s) served as the reported FMD. An increase in FMD over time indicates improved endothelial function. An acceptable reproducibility during longitudinal evaluations is a mean difference of less than 2–3 % . TherefoSerum concentrations of FGF-23 were measured in duplicate after a single thaw of stored blood specimens using an intact FGF-23 ELISA kit . Measurements in blood samples obtained at 1 month following kidney transplant served as the initial FGF-23 level. The longitudinal assessment of FGF-23 levels was performed on blood samples obtained at the 24-month follow-up. The coefficient of determination from the primary standard deviation curve for the FGF-23 measurements was 0.9999, indicating high reproducibility.The primary outcome was defined as the change in FMD from the one-month post kidney transplant evaluation to the 12-month follow-up. Secondary outcomes include the change in FMD from 1 month to 24 months following kidney transplant, change in FMD from 12 months to 24 months following kidney transplant, and change in FGF-23 from 1 month to 24 months post-kidney transplant. We also examined the association between FGF-23 levels and the progression of FMD from 1 month to 24 months following kidney transplantation.Descriptive statistics were presented as median with interquartile range (IQR) or mean with standard deviation (SD) for continuous variable and as percentages for categorical variables. We compared the differences in patients characteristics at month one between the patients who followed up at 12 months post transplant with those patients who did not return for evaluation using either Pearson’s chi-square test  or Wilcoxon rank sum test (for continuous variables). A linear mixed effects model with random intercepts was used to assess the change in FMD over time without and with adjustment for age, race, gender, smoking history (pack years), months on dialysis prior to transplant, cardiovascular disease, mean arterial pressure (MAP), diabetes, and estimated glomerular filtration rate (eGFR). Months on dialysis prior to transplant, eGFR, MAP, pack years, and age were included in the models as non-linear terms using restricted cubic splines. Cardiovascular disease was defined as a history of coronary artery disease, myocardial ischemia, reperfusion (coronary artery bypass or percutaneous stent), congestive heart failure, arrhythmia, stroke, or peripheral vascular disease.a priori. Analyses were performed using R, version 3.1.2 (http://www.r-project.org/). The 5 % significance level (2 sided) was used.A linear mixed effects model with random intercepts was used to examine the change in FGF-23 concentrations over time without and with adjustment for age, race, gender, cardiovascular disease, time on dialysis prior to transplant, and eGFR. In order to meet the normality assumption of the residuals, FGF-23 concentrations were natural logarithmic transformed. All the covariates for both models were chosen n = 149, mean age 49, SD = 39 years) was 74 % male and 75 % White. The most common underlying etiology for ESRD was vascular disease . Seventy-two patients (48 %) reported to be either current or former smokers, and 40 and 38 % of the cohort had a history of cardiovascular disease and diabetes, respectively. The median time on dialysis prior to kidney transplant for the cohort was 20.3 months . Fifteen percent of the study cohort did not require hemodialysis prior to transplant. In regards to medications that may affect the progression of endothelial function, only 3 % (4/149) of the cohort were taking angiotensin converting enzymes inhibitors and angiotensin receptor blockers, 4 % (6/149) were taking a vasodilator, 7 % (11/149) were taking an alpha blocker, and 20 % (29/149) were taking a statin. Throughout the two-year study period, there was one major cardiac event  that occurred between the 12 and 24-month follow up. There were six reported events of angina  and one dysrhythmic event (occurred prior to the 12 month follow up).The study cohort included 149 patients who underwent evaluation at 1 month following kidney transplantation. Demographic and other patient characteristics are presented in Table Eighty-six patients had subsequent clinical follow-up at 12 months, and 44 patients at 24 months . Compared to month one, FMD numerically decreased by 0.56 %  at month 12. In the adjusted model controlling for age, race, gender, smoking history (pack years), months on dialysis prior to transplant, cardiovascular disease, MAP, diabetes and eGFR, FMD remained stable over time . Compared to month one in the adjusted model, FMD numerically decreased by 0.66 % at month 12, but this was not statistically significant  (Table P = 0.031), and FMD decreased significantly with age (P = 0.038).The median FMD at one-month post-kidney transplant for the cohort was 6.3 % (IQR: 3.4–10.2) and at 12 months was 5.4 % (IQR: 3.1–8.5) (Table P = 0.746) and from 12 months to 24 months  post-transplantation.The median FMD for the cohort at 24 months was 5.6 % (IQR: 3.5–9.1)   compared to month one.Forty-five patients were included in the analysis that measured FGF-23 at 1 month and 24 months follow-up after kidney transplantation. Fibroblast Growth Factor 23 decreased significantly over time (P = 0.799). With one interquartile range (~100 picograms per milliliters) decrease in FGF-23, FMD decreased by 0.11 %  over time from 1 month to 24 months post transplant. In addition, there was no significant association between FGF-23 and FMD at month one (P = 0.959) or month 24 (P = 0.699).Adjusting for age, race, gender, cardiovascular disease, time on dialysis prior to transplant and eGFR, there was no statistically significant relationship between FGF-23 and FMD following kidney transplant  [2 (kg/m2) [P = <0.001)) and 12 months following transplant (12 months: 12.1 ± 3.6 % (P = <0.001)) [2 [P = <0.001) [Endothelial dysfunction is universally present in dialysis patients, and previous studies have demonstrated a favorable change in FMD comparing pre and post-transplantation. Kocak et al demonstrated that FMD significantly improved 14 days after kidney transplant  , and rep<0.001)) . Yilmaz Our study, in contrast, examines the longer-term effect of kidney transplantation on endothelial function, showing that FMD remains relatively stable from 1 month to 24 months post transplant. The patients in our cohort were initially evaluated at 1 month post transplant, a time when many of the biochemical abnormalities related to uremia have corrected and complications related to rejection or infection are rare.Strengths of our study include the size of our cohort and duration of longitudinal follow-up. Moreover, the population in our study is older and includes a substantial proportion of patients with cardiovascular disease or diabetes, compared to the previously mentioned studies that were conducted among select groups of relatively young transplant recipients. Thus, a potential explanation for the lack of ongoing improvement in FMD in our study is the high cardiovascular risk profile of the transplant recipients. However, our study population is more reflective of the ESRD and transplant recipient population in the United States and Europe, which improves the generalizability of our findings compared to prior reports. Another strength of our study was that a single sonographer performed the FMD study in the entire cohort, which improves the reliability of the results. The advantage of using brachial artery FMD as a surrogate for coronary artery endothelial health is that the test is non-invasive with reproducible results in the same patient over time when performed by the same examiner.P = 0.02)) in a high cardiovascular risk patient population  with hyperlipidemia who took pravastatin compared to placebo [A limitation of the study is the lack of a pre-transplant FMD measurement. There are reports that note FMD improves rapidly with favorable modification of cardiovascular risk factors. In the prospective, randomized RECIFE trial, FMD was shown to significantly improve in just 6 weeks (4.93+/−0.81 % to 7.0+/−0.79 % ( placebo . This st placebo , 13, 14 Fibroblast Growth Factor-23 has been shown to be significantly elevated in patients with chronic kidney disease as FGF-23 metabolism and clearance are modified , 32, whiFurther limitations of our study include the high percentage of patients who did not complete the follow up. A sensitivity analysis did not show any significant demographic or clinical differences between patients who did not return for the 12 month follow up compared to patients who completed the study, suggesting that any bias is likely to be minimal, though in characteristics not examined cannot be ruled out. Another limitation of our study is that measurements for maximal FMD were obtained at set time points of 60 and 90 s. Without a continuous evaluation, the maximum diameter change secondary to reactive hyperemia may not have been captured with these set time point measurements. In addition, FMD can be affected by temperature, foods, drugs, sympathetic stimuli, environmental factors, and patient’s positions, which can vary over time at each evaluation. The study protocol attempted to minimize this variation by asking all patients to not consume tobacco, food or liquids for 8 h prior to the evaluation. In addition, cardiovascular medication such as angiotensin converting enzyme inhibitors and statins that could affect endothelial function were not controlled for in the study cohort.In a single center, prospective study of medically stable, kidney transplant recipients who were initially evaluated at 1 month following surgery, FMD remained stable over a 24 month follow up period. Consistent with previous work, FGF-23 levels significantly decreased following kidney transplant, however this decrease was not associated with improvement in FMD. The stable FMD in our study cohort suggests that the improvement in endothelial function is maintained up to 2 years post transplantation. However, the lack of continued improvement in endothelial function may contribute to the persistently elevated cardiovascular risk in transplant patients compared to the general population despite improved renal function. Further prospective research regarding endothelial function following kidney transplant would provide important insight into possible mechanisms whereby transplantation impacts cardiovascular health, which would allow interventions aimed at the prevention and reversibility of cardiovascular diseases.


However, to the best of our knowledge, no data are available on the cerebrovascular effects of argon (Ar) in humans. We hypothesized that argon inhalation does not affect mean blood flow velocity of the middle cerebral artery (Vmca), cerebral flow index (FI), zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe), resistance area product (RAP) and the arterio-jugular venous content differences of oxygen (AJVDO2 versus 70%N2/30%O2 in 29 male patients under fentanyl-midazolam anaesthesia before coronary surgery. Vmca was measured by transcranial Doppler sonography. ZFP and RAP were estimated by linear regression analysis of pressure-flow velocity relationships of the middle cerebral artery. CPPe was calculated as the difference between mean arterial pressure and ZFP. AJVDO2, AJVDG and AJVDL were calculated as the differences in contents between arterial and jugular-venous blood of oxygen, glucose, and lactate. Statistical analysis was done by t-tests and ANOVA.In a secondary analysis of an earlier controlled cross-over trial we compared parameters of the cerebral circulation under 15 minutes exposure to 70%Ar/30%O2, AJVDG, and AJVDL.Mechanical ventilation with 70% Ar did not cause any significant changes in mean arterial pressure, Vmca, FI, ZFP, CPPe, RAP, AJVDOShort-term inhalation of 70% Ar does not affect global cerebral circulation or metabolism in male humans under general anaesthesia. Compared to xenon, it has a higher natural abundance in the atmosphere   and cereUp to now the cerebrovascular and cerebrometabolic effects of argon have not been investigated in humans, which may be essential for a possible future clinical application of argon as an organoprotective agent. We performed a larger series of clinical studies using an argon inhalation method for measurements of global cerebral blood flow (CBF), a modification of the Kety-Schmidt technique. In a prospective, controlled, cross-over study design, we investigated the effects of hyperventilation versus hypoventilation in anesthetized patients on parameters of circulation and cerebral metabolism, which in part has been recently published . In the per se might have any influence on the cerebrovascular and cerebrometabolic variables. Because of the recent interest in potential organoprotective properties of argon, we believe that these data should be made accessible to the scientific community.The original rationale for this substudy was a methodological question, as we wanted to rule out the possibility, that our method of CBF measurement  2-reactivity of CBF, cerebral blood flow velocity of the middle cerebral artery (Vmca), and cerebral metabolic rate of oxygen, glucose and lactate  in 30 patients before cardiovascular surgery at the University of Göttingen Medical Centre, Germany. CBF was measured using the modified Kety-Schmidt inert gas saturation technique with stable argon gas as an indicator (70% Ar / 30% O2 gas mixture). Vmca was simultaneously measured by transcranial Doppler sonography (TCD) [2 [In this prospective controlled study we investigated the cerebrovascular COhy (TCD) . Subsequhy (TCD) , (ii) ofhy (TCD) , and (ii(TCD) [2 .per se has any influence on cerebrovascular circulation or metabolism. Thus haemodynamic and laboratory data, which have been used to calculate variables of the first point of measurement in previous publications, are partly used in this analysis [For quality control purposes, we also studied in these patients the cerebrovascular and metabolic effects of argon itself at the beginning of each series of CBF measurements. The primary rationale for this analysis was to investigate if our method of CBF measurement (argon saturation method) analysis –12.Cerebral flow index (FI), effective cerebral perfusion pressure (CPPe), cerebral zero flow pressure (ZFP), and the inverse slope of pressure-flow velocity relationships  were calculated in addition to standard variables from transcranial Doppler and haemodynamic recordings.The study project followed the recommendations of the Declarations of Helsinki and the European Union Commission and European Medicines Agency (Council Directive 91/507/EEC and 75/318/EEC). Ethical approval for this study was provided by the Medical Ethical Committee of the Georg-August-University of Göttingen, Göttingen, Niedersachsen, Germany , Ethical Committee N° 07/09/90). The trial has been retrospectively registered at the German Clinical Trials Registry (No.: DRKS00011535).2), glucose (AJVDG), and lactate, (AJVDL). We hypothesized that in patients under intravenous anaesthesia short-term inhalation of 70% argon does not alter cerebral haemodynamics or metabolism.The endpoints of the study were changes in the mean Vmca, FI, CPPe, ZFP, RAP, and the arterio-jugularvenous content differences of oxygen  and end of the argon wash-in period (argon), to measure variables of blood gas analysis , glucose and lactate.Blood flow velocity in the proximal (M1) segment of the middle cerebral artery (Vmca) was measured by TCD. To ensure a constant position of the ultrasound probe during the investigation period, we used a probe holder . During measurements the patients’ heads were fixed in midline position. Arterial blood pressure was measured invasively in the radial artery, ipsilateral to the TCD probe.The analyses of the ZFP, CPPe and RAP have been performed after the study period. Cerebral ZFP was calculated from data at baseline and at the end of each argon gas saturation phase from two simultaneous 10 s recordings (two breathing cycles) of the Vmca curves and arterial pressure curves. Over each 10 s period we first averaged consecutive pairs of diastolic, mean and systolic data of ABP and Vmca. These data were used to generate a pressure/flow velocity plot. ZFP was then extrapolated by linear regression analysis of the ABP-Vmca relationship. The ABP axis intercept of the regression line determines the ZFP ,16. The Inside the spectral envelope each velocity has an intensity , which is proportional to the volume of blood at this velocity. The flow related to that volume of blood is therefore proportional to the product of its velocity and acoustic intensity. Summing these different flows gives a flow index (FI), which is proportional to total flow. The FI was thus computed as the sum of each acoustic intensity within the TCD spectrum multiplied by the corresponding velocity. We averaged all signals over the entire waveform, which yields the mean FI for that particular 10 s interval –21.x, was calculated as AJVD(x) = Ca(x)—Cjv(x). We calculated the difference in arterio-jugular venous content of oxygen (AJVDO2), glucose (AJVDG), and lactate (AJVDL) [The arterial-to-jugular venous concentration difference of a substance  (AJVDL) . By defiP-value) [In this secondary analysis study setting a prior sample size calculation was not performed. Each patient served as his own control. The results presented are expressed as mean (standard deviation) unless otherwise stated. Normal distribution of data was assessed both visually with inspection of histograms and with the D'Agostino-Pearson omnibus K2 method. The differences between baseline and argon gas inhalation were calculated using t-tests for paired data or Welch-test and non-parametric Wilcoxon signed-rank test, if indicated . To provP-value) . In caseP-value) .® for Mac 2011 . Statistical procedures and graphs were made using Prism 6.0 .All statistical analyses were performed two-sided and a p-value of p< 0.05 was considered to be significant. Database sheets were done by MS ExcelThe study period was 27 months . A total of 30 male patients were examined. In one patient an unexpected sudden increase in heart rate and blood pressure occurred after an unintended surgical stretcher movement during the recordings. This was interpreted as a short phase of insufficient depth of anaesthesia, which ceased following an additional bolus of fentanyl and midazolam. The patient was thereafter completely excluded from further analysis because we assumed insufficient steady state conditions.The mean TCD-insonation depth of the MCA was 51 (3) mm. TCD signals were of high quality in all patients except for two patients during the baseline measurement (patient 1 and 5). These data have been excluded from respective analysis.2 baseline 97 (1)% and argon 96 (2)%, MD 1, 95% CI 1 to 1, P < 0.01), and arterial partial pressure of oxygen (PaO2 baseline 139 (42) mmHg and argon 109 (26) mmHg, MD 29, 95% CI 17 to 41, P < 0.01). Arterial lactate concentration showed a very small but significant increase (LacART baseline 0.59 (0.16) mmol·L-1 and argon 0.63 (0.17) mmol·L-1, MD -0.04, 95% CI −0.08 to -0.01, P 0.04). Levels of haemoglobin were unchanged before and after argon exposure (Hb baseline 12.7 (1.4) mg·dL-1 and argon 12.7 (1.4) mg·dL-1, MD 0.01, 95% CI −0.06 to 0.08, P 0.84) as well as levels of jugular venous oxygen saturation (SjvO2 baseline 50 (10)% and argon 50 (11)%, MD 0.44, 95% CI −0.78 to 1.67, P 0.46).Mean age of the included 29 patients was 56 (6) yrs. , mean height 174 (6) cm, and mean body weight 78 (8) kg. One of our patients had diabetes mellitus type 2, treated with biguanides. None of the patients showed increased levels of blood glucose. A minimal, but significant decrease of mean blood temperature between the two periods of measurements was observed (Temp baseline 35.6 (0.5)°C, argon 35.5 (0.5)°C, MD 0.1, 95% CI 0.07 to 0.2, P< 0.01). There was a minimal decrease in heart rate (HR) baseline 58 (8) bpm and argon 56 (8) bpm, MD 2; 95% CI 1 to 2, P < 0.01), arterial oxygen saturation , mean Vmca, FI, ZFP, CPPe, RAP AJVDO2, AJVDG and AJVDL.When comparing inhalation of 70% NThe most important haemodynamic and metabolic data are presented in 2 levels of the patients were effectively kept constant (mean PaCO2 baseline = 36 (5) mmHg, , mean PaCO2 argon = 37 (7) mmHg . The mean difference of PaCO2 between the baseline and the argon measurements was minimal MD = −0.6 (2.4), CI −1.5 to 0.36 mmHg, P 0.22 .Ventilation parameters and PaCO2, AJVDG and AJVDL when comparing inhalation of 70% Ar / 30% O2 with 70% N2 / 30% O2We investigated the effects of an argon-oxygen gas mixture on cerebral circulation and metabolism in cardiovascular patients under fentanyl-midazolam anaesthesia. The most prominent result of our study is that no significant and clinically relevant changes were found in Vmca, FI, CPPe, ZFP, RAP, AJVDOin vitro and in vivo animal studies, but rarely in humans. Medical research in the 1930s among military divers was one of the earliest observations of the biological effects of argon. Argon is well known to be inert at standard gas conditions. Mental impairment at high pressures had been observed [To the best of our knowledge, this study is the first report about cerebrovascular and cerebrometabolic effect of argon in humans. Most of the data on biological effects of argon has been accomplished by observed , 27. Oneobserved . These dobserved . RecentlTranscranial Doppler sonography measures flow velocity in the basal cerebral arteries. Today, Vmca and its indices are routinely used to assess components of cerebral circulation. Although Vmca is not a direct measure of CBF, changes in flow velocity generally correlate well with changes in CBF, except for specific situations, which may affect MCA diameter such as vasospasm, hypercapnia, migraine attacks, nitroglycerine, or other vasoactive agents –32. In oThe noble gas xenon has excellent narcotic properties and may affect cerebral circulation , 34. TriCerebral ZFP, CPPe and RAP are supplemental determinants of cerebral blood flow. Using the CPPe as the driving pressure of the cerebral circulation does not require invasive measurements of intracranial pressure (ICP) and offers advantages in understanding pathophysiology, because changes of the effective downstream pressure irrespective of ICP will also be reflected by this kind of calculation ,15. The 2 less than 50% whereas cerebral ischemia is assumed when SjvO2 is less than 40% and AJVDO2 is greater than 9 ml·dL-1 [2 [2 and unchanged arterio-jugular venous content differences of oxygen, glucose, and lactate  suggest intact flow-metabolic coupling of the brain [2 and/or arterio-jugular venous content difference of oxygen, glucose, and lactate. The coupling of cerebral flow and metabolism thus seems to be unchanged during argon exposure and our findings indicate a constant cerebral metabolic rate of oxygen and glucose.Reports on the effect of argon on CBF and parameters of cerebral metabolism are not available up to now. Global cerebral hypoperfusion often is defined as a SjvO ml·dL-1 . Total i·dL-1 [2 . Thus, ahe brain , 49. In he brain . In our in vitro models of cerebral ischemia and traumatic brain injury [Despite the increasing comprehension of neuroplasticity and neuroprotection, the exact mechanisms by which argon improves outcome remain far from being understood . Besidesn injury . Brückenn injury . In a pon injury .Our study was not designed to assess the neuroprotective effect of argon ventilation. Based on our observations and the previous, safe use of argon in adults in the past, as well as the efficacy studies described above, further safety studies in humans  appear warranted.Some methodological aspects of our study have to be considered.per se may have confounded our results. However, the results of this study cannot a priori be extrapolated to other types of anaesthesia. Similarly, the external validity of our data could be limited by the fact that some of our patients with coronary artery disease might be suffering from concomitant asymptomatic cerebrovascular disease.The type of anaesthesia may have potential influence on the results of our study. We have no reason to assume that intravenous anaesthesia with fentanyl and midazolam 2 and PaO2. All patients have been ventilated by two identical anaesthesia machines. When starting the argon-wash-in-period we changed the ventilators, using identical respiratory settings and identical inspired oxygen fraction. The mild decrease in SaO2 and PaO2 might be related to the short discontinuation of PEEP during this manoeuvre. Fortunately, our measurements did not affect general conditions in our patients. All surgical procedures were without complications. All patients had been discharged from ICU within 2 days. There were no suspected unexpected serious adverse reactions (SUSARS) or serious adverse events (SAE).Unexpectedly, there was a very slight reduction in SaO2) did not show any effects on the cerebral circulation or on global oxygen and glucose metabolism. The lack of cerebrovascular and cerebrometabolic effects suggests future studies on the use of argon which should confirm the safety of argon inhalation during longer periods and may investigate the organ protective effects of argon in humans.In male cardiac surgical patients under fentanyl-midazolam anaesthesia, short-term ventilation with argon (70%Ar / 30% OS1 FileNo legend.(XLSX)Click here for additional data file.S1 Table2 / 30% O2. Argon = inhalation with 70% Ar / 30% O2. The P values, which refer to the difference between two measurement points, were calculated using two-sided t-test for paired data (* P<0.05). Due to artefacts during blood pressure recording, data of patient 1 has been excluded from respective analysis § n = 28. CI = confidence interval , GlucART = arterial blood glucose concentration, GlucJV = jugular bulb blood glucose concentration, Hb = haemoglobin concentration, Hct = haematocrit, HR = heart rate in beats per minute, K = serum potassium concentration, LacART = arterial blood lactate concentration, LacJV = jugular bulb blood lactate concentration, MD = mean differences, MAP = mean arterial blood pressure, Na = serum sodium concentration, pHART = pH of arterial blood, pHJV = pH of jugular bulb blood, PaCO2 = arterial partial pressure of CO2, PjvCO2 = jugular bulb partial pressure of CO2, PaO2 = arterial partial pressure of O2, PjvO2 = jugular bulb partial pressure of O2, SaO2 = arterial blood oxygen saturation, SjvO2 = jugular bulb blood oxygen saturation, SBC = standard bicarbonate concentration, SD = standard deviation.Baseline = inhalation of 70% N(DOCX)Click here for additional data file.


GNRI levels were also independently correlated with CRP levels . During follow-up period, 283 (29.1%) patients died, including 123 (12.6%) due to cardiovascular disease (CVD). Abnormal ABI (adjusted hazard ratio (HR) 1.62, 95% CI 1.13–2.32, p = 0.0096), GNRI < 91.2  and CRP > 1.9 mg/L  independently predicted mortality due to CVD, respectively. In conclusion, abnormal ABI, GNRI, and CRP levels were closely associated with each other, and the combination of these variables increase their predictive values for the risk of mortality due to CVD and all-cause mortality in HD patients. Protein-energy wasting (PEW) is highly prevalent in hemodialysis (HD) patients. We investigated the association of abnormal ankle brachial index (ABI), PEW, and chronic inflammation status with clinical prognosis in HD patients. A total of 973 HD patients were enrolled and were followed-up for 8 years. As a marker of the PEW, geriatric nutritional risk index (GNRI) was used. Cut-off levels were 91.2 for GNRI defined from previous studies and 1.9 mg/L for C-reactive protein (CRP) as median value, respectively. Abnormal ABI was seen in 332 (34.1%) patients. Declined GNRI and elevated CRP levels were independently associated with abnormal ABI (odds ratio (OR) 0.97, 95% confidence interval (CI) 0.96–0.99,  Patients on hemodialysis (HD) are at an extremely high risk of cardiovascular disease ,2. The iIn the clinical settings, peripheral artery disease (PAD) is frequently seen in patients on hemodialysis (HD) . AdditioOn the other hand, malnutrition and inflammation are highly prevalent in HD population. These association are characteristics for protein energy wasting (PEW) . RecentlIn the study, we investigated the association of abnormal ABI, GNRI, and chronic inflammation status detected by C-reactive protein (CRP) levels with clinical prognosis in HD patients. In addition, we explored whether combination of these factors can more accurately predict clinical outcomes in such a high-risk population.We enrolled a total of 973 clinically stable outpatients stably undergoing maintenance HD therapy for at least a month in Nagoya Kyoritsu Hospital with three associated clinics in Japan: the Central Clinic, the Ama Kyoritsu Clinic, and the Meiko Kyoritsu Clinic, respectively. To them, ABI, GNRI, and CRP levels were measured from January in 2007 to April in 2008. In this retrospective, the observational follow-up study, we investigated the association of ABI, PEW, and chronic inflammation status with mortality due to cardiovascular disease (CVD) in HD patients, and enrolled subjects were followed-up for 8 years. In advance, those with malignancy and/or active inflammatory diseases were excluded from the study. In the study, hypertension was defined as pre-dialysis systolic blood pressure >160 mm Hg and/or diastolic blood pressure >90 mm Hg, or a history of anti-hypertensive treatment [The physicians obtained written informed consent from each patient, and the study was approved by the hospital ethics committee. The results have not been published previously except in abstract form.The endpoints were mortality due to CVD and all-cause mortality. Mortality due to CVD was defined as death due to cerebrovascular events, myocardial infarction, heart failure, and/or arrhythmia, other cardiovascular related death, or sudden death for unknown reasons. Clinical data were obtained from hospital charts and telephone interviews with patients by trained reviewers blinded to patients’ clinical backgrounds. ABI, which simultaneously measures systolic blood pressure in the arm  and ankle blood pressure, was measured by using a Colin Waveform analyzer . Abnormal ABI was defined by the following criteria: ABI < 0.9 or ABI > 1.4. As a marker of the PEW, geriatric nutritional risk index (GNRI) was calculated as follows: GNRI =  + (41.7 × (body weight/body weight at BMI of 22)) . Serum Cp < 0.05 by univariate analysis. Relationship between GNRI and baseline variables were evaluated by multivariate regression analysis.In the study, we used SAS 6.10 software  for statistical analyses. Variables with a normal distribution are expressed as mean values ± SD, and asymmetrically distributed data are given as median and interquartile range. Differences among the groups were evaluated by one-way analysis of variance (ANOVA) or Kruskal–Wallis test for continuous variables and by the chi-square test for categorical variables. Associated factors for abnormal baseline ABI were identified by use of the logistic model, and the multivariate model included all baseline valuables with p < 0.05 by univariate analysis were entered into a multivariate model. We calculated the C-index for receiver-operating characteristics curve, the net reclassification improvement (NRI) and the integrated discrimination improvement (IDI) to assess whether the values for predicting endpoints improved after the addition of an abnormal ABI, a GNRI < 91.2, and a CRP > 1.9 mg/L to a baseline model with established risk factors, which were baseline variables with p < 0.05 by univariate analysis, such as male sex, age, diabetes, previous CAD, previous stroke, hemoglobin, and creatinine.Differences in event-free survival among the groups with risk factors, such as an abnormal ABI, a GNRI < 91.2, and a CRP > 1.9 mg/L, were examined with the Kaplan–Meier method and compared using a log-rank test. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for each factor by a Cox proportional hazards analysis. In addition, to determine independent predictors for the endpoints, all baseline variables with p < 0.05.Differences were considered significant at p = 0.0009 and OR 1.40, 95% CI 1.07–1.83, p = 0.013, respectively) (p < 0.0001) (Baseline characteristics in study population are shown in ctively) . CRP lev 0.0001) .p = 0.0096), a GNRI <91.2 , and a CRP >1.9 mg/L  were independent predictors for mortality due to CVD, respectively (p < 0.0001) (p < 0.0001) (p < 0.0001) higher risk for mortality due to CVD compared to those without any risk factor after adjustment for other confounders. Similar results were obtained in all-cause mortality  (During follow-up period (median 46 months), 39 patients moved to other institutions and 9 underwent kidney transplantation, and they were censored at the point of dropping out. A total of 283 (29.1%) patients died including 123 (12.6%) due to CVD. An abnormal ABI  . As for  0.0001) . Patient 0.0001) .To determine model discrimination, the C-index was calculated. Adding both ABI and GNRI significantly increased the C-index to predict mortality due to CVD, compared to a combination of established risk factors only. The C-index for all-cause mortality was higher in a baseline model with either ABI, GNRI, or CRP levels than in the baseline model alone . In the study, we found that the combination of ABI, GNRI, and CRP levels strongly increase their predictive values for mortality due to CVD and all-cause mortality risk in HD patients. Because HD patients have high prevalence of cardiovascular events, simple methods to predict clinical outcome in the HD population. From this perspective, our findings are of great significance. In addition, declined GNRI and elevated CRP levels were associated with abnormal ABI in HD patients.Malnutrition status is now considered as one of independent predictors of poor prognosis in high-risk subjects such as the elderly population  and thosSome methods have been used to estimate nutritional status. As screenings for daily clinical practice, simple and practical tools using routinely measured data may be ideal. The GNRI is calculated from both serum albumin, and the components of BMI have been developed as a simplified screening tool to assess nutritional risk . This inRecently, we have reported that predictability for mortality with GNRI is broadly comparable with criteria of PEW recommended by the International Society of Renal Nutrition and Metabolism (PEW-ISRNM), using serum albumin, BMI, mid-arm muscle circumference area, and daily protein-energy intake . TherefoIn our study, stratification by the positive number of risks factors could accurately predict mortality. Declined GNRI and elevated CRP levels were independently associated with abnormal ABI. In addition, CRP levels were also independently correlated with GNRI levels. All these factors are associated with each other; however, GNRI and ABI may more accurately reflect the nutritional status or vascular injury, respectively. The combination of these three factors can reflect not only inflammation but also malnutrition and atherosclerosis, and are therefore useful to assess PEW.Some limitations should be discussed. First, this was a retrospective study with limited numbers of enrolled patients. Therefore, multi-center studies with large populations are needed to confirm our findings. Second, characteristics of our subjects such as body mass index, lipid profiles, and other factors were quite different from those in the Western countries. Third, ABI do not necessarily reflect presence of PAD. Patients on HD frequently have medial artery calcification, especially a high or normal ABI value. Fourth, we had no data on medications. Some medications such as statins, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers might affect the results. Final, we only checked measurements at one time. Interval changes of the three parameters were not evaluated. In addition, revascularization for PAD before and after the enrollment was not considered. Additionally, values of blood pressure were not evaluated in the analysis. These limitations should be considered to interpret the results. In conclusion, ABI, GNRI, and CRP levels were closely associated with each other, and the combination of these variables strongly increased their predictive values for mortality due to CVD and all-cause mortality risk in HD patients. Thus, a relationship among malnutrition, inflammation, and atherosclerosis might manifest in this high-risk population.


Blood pressure (BP) is a complex, multifactorial clinical outcome driven by genetic susceptibility, behavioral choices, and environmental factors. Many molecular mechanisms have been proposed for the pathophysiology of high BP even as its prevalence continues to grow worldwide, increasing morbidity and marking it as a major public health concern. To address this, we evaluated miRNA profiling in blood leukocytes as potential biomarkers of BP and BP-related risk factors.The Beijing Truck Driver Air Pollution Study included 60 truck drivers and 60 office workers examined in 2008. On two days separated by 1–2 weeks, we examined three BP measures: systolic, diastolic, and mean arterial pressure measured at both pre- and post-work exams for blood NanoString nCounter miRNA profiles. We used covariate-adjusted linear mixed-effect models to examine associations between BP and increased miRNA expression in both pooled and risk factor-stratified analyses.Overall 43 miRNAs were associated with pre-work BP (FDR<0.05). In stratified analyses different but overlapping groups of miRNAs were associated with pre-work BP in truck drivers, high-BMI participants, and usual alcohol drinkers (FDR<0.05). Only four miRNAs were associated with post-work BP (FDR<0.05), in ever smokers.Our results suggest that many miRNAs were significantly associated with BP in subgroups exposed to known hypertension risk factors. These findings shed light on the underlying molecular mechanisms of BP, and may assist with the development of a miRNA panel for early detection of hypertension. Hypertension (HTN), defined as systolic blood pressure (SBP) above 140 mmHg or diastolic blood pressure (DBP) above 90 mmHg, is a major public health concern worldwide . DespiteSince EBP results from a set of complex genetic, pathophysiological, and environmental factors  post-tra10 (particulate matter ≤10 μm) affects blood pressure (BP) [Our group previously reported that traffic-related exposure to ambient PMure (BP) , and thaure (BP) . As an aure (BP) . Becauseure (BP) , 27, our+5 years). Each participant was examined twice each on two days one to two weeks apart, for a total of two examination days and four examinations per participant to allow for short-term variations in BP. Blood samples were collected at the end of each examination day only, allowing for two miRNA measures per participant . We used a self-administered questionnaire to collect detailed information on demographics and lifestyle as well as time-varying factors  which were self-reported both for past patterns and day of examination data . Daily temperature and dew point data for Beijing were obtained from the National Oceanic and Atmospheric Administration [The Beijing Truck Driver Air Pollution Study was conducted between June 15 and July 27, 2008 in two groups highly exposed to air pollution: 60 truck drivers and 60 office workers . Both ofstration . IndividA total of 240 peripheral blood samples from 120 participants were collected in PAXgene Blood RNA Tubes  at each post-work exam. Detailed data processing procedures can be found in the Supplemental Materials. Briefly, total RNA was extracted using the PAXgene Blood-RNA Kit Qiagen-763134 . All samples had optical density ratios of 280/260 ≥1.9 and 260/230 ≥1.8. RIN (RNA Integrity Number) scores, thus showing excellent RNA quality (mean: 8.3±0.9). We profiled miRNAs using NanoStringnCounter-miRNA expression analysis . The nCounter miRNA data were also confirmed through cross-platform validation in 20 randomly-selected study samples using the TaqManOpenArray Real-Time PCR Plates  on the QuantStudio 12K Flex Real-Time PCR System. The average Pearson correlation coefficient was 0.73 (0.63–0.79) between the two platforms, thus confirming the robustness of nCounter. The raw and processed miRNA data have been deposited into the NCBI Gene Expression Omnibus (accession number GSE63087). miRNA expression data were processed and obtained as described previously [The seated BP of each individual was measured by a trained research assistant at each examination after a full five minutes of rest. Per the American Heart Association’s standardized measurement protocol, BP was For our descriptive analysis we used mixed-effects linear regression models to assess each of the three BP measures (pre- and post-work) across categories of independent variables (continuous variables were categorized according to the distribution of the data) while incorporating repeated measures data. We also conducted t-tests to compare pre- and post-work BP measures, and generated MA plots of describing differential miRNA expression by pre-work BP level. Next we used mixed-effects linear regression models to evaluate the associations of miRNAs with BP in the entire sample  accounting for repeated measures. We also conducted sensitivity analyses to explore the effect of using the change from pre- to post-work in each BP measurements as an additional outcome, and separate analyses of each visit.2 based on WHO recommendations for BMI measurement and intervention in Asian populations [10). Since miRNA data was log-2 transformed we presented the results as unit change in mmHg of BP per each two-fold increase in miRNA. All statistical tests were two-sided, and BP changes with a Benjamini-Hochberg false discovery rate (FDR) <5% [Next, for our stratified analyses we identified gender, BMI, smoking status, and alcohol consumption as EBP risk factors based on our descriptive analysis (variables associated with BP at p<0.05). We performed stratified analyses on these risk factors as well as occupation  to explulations . For theulations , we alsoFDR) <5%  were conBlood pressure measures before and after work by participant characteristics are summarized in Pre-work BP measured was significantly associated with post-work miRNA expression . We idenFor the stratified analyses we found significant associations between miRNAs and pre-work BP in truck drivers, high-BMI participants, and usual alcohol drinkers  Tables. To our knowledge this study is the first to evaluate miRNA profiling from blood leukocytes in relation to BP among a cohort of Chinese workers. We observed that both pre- and post-work SBP, DBP, and MAP were all higher in participants that were male, had higher BMI, or were smokers; all traditional risk factors of HTN . Our pooPrevious studies have related some miRNAs to molecular changes involved with HTN or cardiovascular diseases. For instance, we identified miR-151-5p as one of the most significant positive miRNA-BP associations in our pooled analysis as well as the strata of truck drivers, high-BMI participants, and usual alcohol drinkers  in the future and highlighting the potential for miRNA-mediated risk factors for HTN and other cardiovascular diseases. Future research should follow these results using larger, more representative populations to identify specific pathways in humans linking the functions of these miRNAs to their role in elevating BP.S1 Table(PDF)Click here for additional data file.S2 Table(PDF)Click here for additional data file.S3 Table(PDF)Click here for additional data file.S1 Fig(PDF)Click here for additional data file.S2 Fig(PDF)Click here for additional data file.


In the PATHWAY-2 study of resistant hypertension, spironolactone reduced blood pressure substantially more than conventional antihypertensive drugs. We did three substudies to assess the mechanisms underlying this superiority and the pathogenesis of resistant hypertension.ClinicalTrials.gov, number NCT02369081.PATHWAY-2 was a randomised, double-blind crossover trial done at 14 UK primary and secondary care sites in 314 patients with resistant hypertension. Patients were given 12 weeks of once daily treatment with each of placebo, spironolactone 25–50 mg, bisoprolol 5–10 mg, and doxazosin 4–8 mg and the change in home systolic blood pressure was assessed as the primary outcome. In our three substudies, we assessed plasma aldosterone, renin, and aldosterone-to-renin ratio (ARR) as predictors of home systolic blood pressure, and estimated prevalence of primary aldosteronism (substudy 1); assessed the effects of each drug in terms of thoracic fluid index, cardiac index, stroke index, and systemic vascular resistance at seven sites with haemodynamic monitoring facilities (substudy 2); and assessed the effect of amiloride 10–20 mg once daily on clinic systolic blood pressure during an optional 6–12 week open-label runout phase (substudy 3). The PATHWAY-2 trial is registered with EudraCT, number 2008–007149–30, and r2=0·13, p<0·0001) and plasma renin . 42 patients had low renin concentrations (predefined as the lowest tertile of plasma renin), of which 31 had a plasma aldosterone concentration greater than the mean value for all 126 patients (250 pmol/L). Thus, 31 (25% [95% CI 17–33]) of 126 patients were deemed to have inappropriately high aldosterone concentrations. Thoracic fluid content was reduced by 6·8% from baseline  with spironolactone, but not other treatments. Amiloride (10 mg once daily) reduced clinic systolic blood pressure by 20·4 mm Hg (95% CI 18·3–22·5), compared with a reduction of 18·3 mm Hg (16·2–20·5) with spironolactone (25 mg once daily). No serious adverse events were recorded, and adverse symptoms were not systematically recorded after the end of the double-blind treatment. Mean plasma potassium concentrations increased from 4·02 mmol/L (95% CI 3·95–4·08) on placebo to 4·50 (4·44–4·57) on amiloride (p<0·0001).Of the 314 patients in PATHWAY-2, 269 participated in one or more of the three substudies: 126 in substudy 1, 226 in substudy 2, and 146 in substudy 3. Home systolic blood pressure reduction by spironolactone was predicted by ARR (Our results suggest that resistant hypertension is commonly a salt-retaining state, most likely due to inappropriate aldosterone secretion. Mineralocorticoid receptor blockade by spironolactone overcomes the salt retention and resistance of hypertension to treatment. Amiloride seems to be as effective an antihypertensive as spironolactone, offering a substitute treatment for resistant hypertension.British Heart Foundation and UK National Institute for Health Research. Resistant hypertension is defined as a blood pressure that is uncontrolled despite treatment with at least three blood pressure-lowering drugs, including a diuretic, usually also including an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) and a calcium channel blocker (CCB), and after exclusion of treatable secondary causes of hypertension.Evidence before this studyWe previously reported the results of the PATHWAY-2 randomised controlled trial, which showed that low-dose spironolactone (25–50 mg daily), when added to standard blood pressure-lowering drugs, was substantially more effective at lowering blood pressure in patients with resistant hypertension than placebo or alternative blood pressure-lowering drugs (bisoprolol or doxazosin). On Sept 17, 2017, we searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials using the search terms “resistant hypertension”, “pathophysiology”, “mechanisms”, “amiloride”, “hemodynamics”, and “aldosterone” for reports in English published up to July 31, 2017. Our search strategy included reports of randomised controlled trials as well as open and observational studies of drug treatment of resistant hypertension that included any data analysing mechanisms and pathophysiology of resistant hypertension or the use of amiloride. The available evidence was scarce. Findings from two observational studies had suggested that plasma renin concentrations were often more suppressed than anticipated in patients with resistant hypertension, consistent with this being a sodium-retaining and volume-expanded state. In another study, non-invasive haemodynamic measurements via impedance cardiography were used to establish whether treatment adjusted on the basis of haemodynamic characteristics would be more effective than empirical treatment at lowering blood pressure in resistant hypertension, but the findings were inconclusive. In a prospective study of 88 consecutive patients referred to a university clinic for resistant hypertension, researchers reported that 18 (20%) had increased urinary aldosterone and suppressed plasma renin concentrations, despite salt intake in excess of 200 mmol/24 h. Background treatment, including β-blockade, was not discontinued. Authors of other observational studies and commentaries have speculated that many cases of resistant hypertension might result from undetected aldosterone-producing adenomas. Results of many studies have shown the efficacy of low-dose (2·5–5·0 mg) amiloride added to thiazide, including reduction of morbidity and mortality. We have previously reported the efficacy of high-dose (10–40 mg) amiloride in treated hypertension, but amiloride has not previously been compared with spironolactone or other drugs in patients with resistant hypertension.Added value of this studyIn the PATHWAY-2 trial, spironolactone reduced blood pressure substantially more than conventional antihypertensive drugs in patients with resistant hypertension. In order for the results of PATHWAY-2 to change practice, it was important to show a mechanistic basis underpinning the superiority of spironolactone. The results of the PATHWAY-2 mechanisms substudies show that the efficacy of spironolactone as an antihypertensive drug could be anticipated from our findings that resistant hypertension is a salt-retaining condition, associated with high aldosterone-to-renin ratios, and that spironolactone was substantially superior to the other standard antihypertensive drugs in reducing indices of salt and water retention—ie, it was reducing blood pressure primarily via diuretic actions. Physicians who are hesitant to prescribe spironolactone for hypertension, either because it is not a universally licensed indication, or because of antiandrogen-related intolerance, will be reassured by our additional finding that amiloride 10–20 mg achieved similar reductions in blood pressure as spironolactone, with similar, slight changes in electrolytes.Implications of all the available evidence2 and serum potassium within the normal range. Among this cohort are likely to be some —perhaps many—patients whose hypertension is caused by primary aldosteronism. We encourage a reconsideration of which diagnostic thresholds for primary aldosteronism are appropriate in patients with resistant hypertension, to facilitate recognition of a potentially curable aldosterone-producing adenomas in patients with resistant hypertension.We propose that spironolactone, or amiloride if spironolactone is not tolerated, should be first-line treatment for resistant hypertension, in addition to background treatment with an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, a calcium channel blocker, and a diuretic, in patients with an eGFR greater than 45 mL/min/1·73mUnderstanding the mechanism of the blood pressure-lowering superiority of spironolactone in resistant hypertension would help to delineate the pathophysiological basis of resistant hypertension and provide a rationale for developing alternative treatment strategies for patients in whom spironolactone is poorly tolerated. The hypothesis underpinning PATHWAY-2 was that resistant hypertension is predominantly a sodium-retaining state (despite background treatment with thiazide-type diuretics) and that further diuretic  treatment would be the most effective means of lowering blood pressure.First, what is the relation between baseline plasma renin, aldosterone, and the aldosterone-to-renin ratio (ARR) and the blood pressure-lowering response to spironolactone, bisoprolol, doxazosin, and placebo? Consistent with our hypothesis that resistant hypertension is predominantly a sodium-retaining state, we expected plasma renin to be relatively suppressed despite background treatment with an ACE inhibitor or an ARB, a CCB, and a diuretic—ie, the so-called A+C+D treatment strategy.Second, we aimed to assess the haemodynamic responses to the various drug treatments and placebo and their effect on cardiac output, systemic vascular resistance, and thoracic fluid content, testing the hypothesis that the superior action of spironolactone in lowering blood pressure in resistant hypertension would be consistent with those of a diuretic.Third, we hypothesised that if the superiority of spironolactone in resistant hypertension was due to its natriuretic actions, then amiloride would similarly decrease blood pressure. Like spironolactone, amiloride is a distal tubular diuretic that inhibits the aldosterone-sensitive epithelial sodium channel. Notably, a low-dose thiazide and amiloride combination achieved a greater reduction in blood pressure from baseline than high-dose thiazide alone in patients with hypertension in the PATHWAY-3 trial.PATHWAY-2 was a 12-month, double-blind, placebo-controlled, randomised, crossover trial done at 12 secondary care sites and two primary care sites in the UK, in patients aged 18–79 years with systolic blood pressure of at least 140 mm Hg and home systolic average blood pressure of at least 130 mm Hg despite treatment with maximum tolerated doses of three blood pressure-lowering drugs . Secondary causes of hypertension had been excluded and specific procedures were done to confirm resistant hypertension and patient adherence to their baseline medications.The haemodynamics and amiloride runout substudies were incorporated within the original protocol of PATHWAY-2, and the aldosterone substudy was added later. By design, each was done in a subset of patients, restricted by either recruitment date , setting (haemodynamic measurements [substudy 2]), or preference of the patient or doctor (amiloride runout substudy 3]).).3, 6 ThIn 2012, roughly halfway through recruitment for PATHWAY-2, additional funding permitted the addition of plasma aldosterone, and thus ARR, to the baseline measurements. The objective of substudy 1 was to compare the ability of plasma aldosterone, renin, and ARR to predict the blood pressure response to each drug and to explore the role of aldosterone in patients with resistant hypertension. Thus, patients recruited after 2012 with available baseline aldosterone measurements were included in substudy 1.Patients were eligible for substudy 2 dependent on which location they were recruited from; seven of the 12 secondary care sites had the necessary specialist equipment. Substudy 2 assessed the effects of spironolactone, bisoprolol, and doxazosin treatments on thoracic fluid, cardiac index, and systemic vascular resistance and whether patients' most effective drug was predicted by increased baseline measurements of the parameter most likely to be reduced by that drug.After the double-blind rotation, patients were offered the option of returning to primary care or continuing into an open-label runout phase (substudy 3). This opportunity for a non-randomised study of an alternative to spironolactone arose from the need for a period between each patient's final visit and completion of their electronic record, after which their best treatment could be unmasked. In this open-label phase, we assessed whether amiloride would have similar superiority to the other study drugs as was hypothesised for spironolactone, and, if so, whether a correlation between responses would support switching from spironolactone to amiloride in patients who became intolerant of spironolactone.All study participants provided written informed consent as part of consent for the main trial and the protocol for these studies was approved by the Cambridge South Research Ethics Committee.In the main PATHWAY-2 trial, after a 4-week single-blind placebo run-in, patients rotated through four cycles of once-daily oral treatment with spironolactone 25–50 mg, doxazosin 4–8 mg, bisoprolol 5–10 mg, and placebo, each for 12 weeks with forced titration to the higher dose after 6 weeks. The order in which drugs were administered to each patient was randomly assigned via a central computer system. Patients and investigators were masked to drug treatment groups. Blood was collected at the end of the placebo run-in, and batched results did not inform eligibility of individual patients for either the main trial or its substudies. Plasma renin was measured in a central laboratory as direct renin mass using the LIAISON automated chemiluminescent immunoassay .2. Stroke index was calculated as stroke volume divided by body surface area (mL per heart beat per m2). Cardiac index (cardiac output) was calculated as stroke index multiplied by heart rate (L/min/m2). Systemic vascular resistance index was then derived from the measurements of cardiac index and blood pressure (dyn ×    sec/cm⁵/m2). Thoracic fluid content index, an index of body fluid volume, is expressed as 1/kΩ/m2. Previous studies have shown these primary variables to be highly reproducible on repeated measures in the same patient, separated by days or weeks.11For substudy 2, non-invasive haemodynamic assessments of fluid balance, cardiac performance, and vascular resistance were done with the patient supine, at baseline and at the end of each treatment cycle, using thoracic electrical bioimpedance cardiography .In substudy 3, participating patients received amiloride 10 mg once daily for 6 weeks, followed by the option to up-titrate to 20 mg daily for a further 6 weeks if blood pressure remained uncontrolled . Seated In the main PATHWAY-2 study, blood pressure was measured both as a home blood pressure average and seated clinic blood pressure. For substudy 1 examining the relations between hormones and the blood pressure response to treatment, home systolic blood pressure measurements were used. Home blood pressure was a single mean of 24 seated home blood pressure readings recorded in the morning and evening for 4 consecutive days, with triplicate readings at each measurement session. Home blood pressure was recorded over the 4 days before the baseline visit at the end of placebo run-in, and before the 6-week and 12-week visits of each double-blind treatment cycle. If incomplete, a minimum of six of the 24 possible blood pressure recordings over 4 days was required, or patients were excluded from the analysis.Home blood pressure was not recorded during the open-label amiloride runout phase. Thus in substudy 3, the clinic blood pressure-lowering effect of amiloride was compared with clinic blood pressure reduction on other active treatments or placebo. Clinic blood pressure was the average of the last two of the triplicate readings recorded at the 6-weekly study visits during both the double-blind treatment cycles and the open-label amiloride runout. Visits could be morning or afternoon, but were at a consistent time of day for each patient. The home and clinic blood pressures were measured by a WatchBP Home monitor , allocated to the patient for the year of double-blind treatment.The prespecified objectives and outcome measures for these mechanistic substudies of the PATHWAY-2 trial were to define the relations between baseline plasma renin, aldosterone, and ARR (on background treatment with A+C+D) and the blood pressure response to spironolactone, doxazosin, bisoprolol, and placebo; to analyse the haemodynamic response to the blood pressure-lowering treatments in resistant hypertension to establish their most likely mechanism of action; and to use the open-label runout phase of the study to establish whether amiloride would achieve blood pressure reductions similar to spironolactone in patients with resistant hypertension. Exploratory analyses of the prevalence of primary aldosteronism were also done. Only serious adverse events were recorded during the open-label amiloride runout.In the aldosterone substudy (substudy 1) of patients who had a baseline measurement of ARR, the main outcomes were the baseline measurement of ARR, and the regression upon this of the change from baseline in home systolic blood pressure averaged (mean) across the 6-week and 12-week visits of each double-blind treatment. In the haemodynamic substudy (substudy 2) of patients at the seven sites that had a CardioDynamics BioZ Impedance Cardiography Hemodynamic Monitor , the main outcomes were the changes in thoracic fluid index, cardiac index, stroke index, and systemic vascular resistance between baseline and the end of each double-blind treatment. In the amiloride substudy (substudy 3) of patients who continued after the double-blind treatment cycles into an optional open-label runout on amiloride, the main outcome was change in clinic systolic blood pressure between baseline and end of 6 weeks (low-dose) or 12 weeks (high-dose) of amiloride treatment. In all substudies, treatment refers to the study drug administered in addition to the background treatment with A+C+D .This PATHWAY-2 mechanisms study is a series of prespecified substudies embedded within the PATHWAY-2 trial.−1)−1 for the SUSPPUP ratio ([serum sodium/urinary sodium])/([serum potassium2/urinary potassium]).In substudy 1, we used regression analyses to explore the relation between each of baseline plasma renin, aldosterone, and the ARR and blood pressure responses to the active treatments and placebo. Exploratory analyses were post hoc, but when appropriate followed the prespecified PATHWAY definition of high and low renin concentrations being those within the upper and lower tertiles of the plasma renin distribution. The prevalence of primary aldosteronism was estimated using the threshold of 60·94 for ARR in the post-captopril suppression test, and a threshold of 5·3 . Data checking for compliance with protocol were done by the Robertson Centre for Biostatistics, University of Glasgow (UK). The PATHWAY-2 trial is registered with EudraCT, number 2008–007149–30, and The funders of the study had no role in study design, data collection, data analysis, data interpretation, or the writing of the report. The investigators and all authors had sole discretion in the data analysis, interpretation, writing of the report, and the decision to submit for publication. The corresponding author had full access to all of the data and the final responsibility to submit for publication.Between May 15, 2009, and July 8, 2014, we screened 436 patients for the PATHWAY-2 study. 335 were randomly assigned to treatment groups, of whom 21 had no follow-up for any drug and were excluded from the intention-to-treat analysis, which comprised 314 patients. Of these, 126 patients had baseline measurements of aldosterone and ARR, 226 participated in the haemodynamic analyses with impedance cardiography, and 146 participated in the amiloride runout phase of the study .Figure 2The baseline characteristics of the patients in the three substudies and the overall trial population were similar . The mear2=0·13, p<0·0001), by plasma renin , and weakly by plasma aldosterone alone . The best fit was quadratic , but not in women −1.Aldosterone and renin concentrations were not linearly correlated . Thoracic fluid index was significantly increased by 0·57 1/kΩ/m2 with doxazosin compared with placebo  and increased stroke volume index by 6·5 mL per heart beat per m2 , reflecting a reduction in heart rate. Vascular resistance index showed a small but significant reduction with all treatments, including placebo, with no apparent differences between treatments (p=0·066). Baseline haemodynamic characteristics did not predict the blood pressure response to treatment , clinic blood pressure after 6 weeks was similar to the patients' previous measurements on spironolactone, and much lower than those on either placebo or the other two active treatments  of 126 patients have an inappropriately high plasma aldosterone concentration—ie, that is greater than the mean for all patients in the substudy despite a plasma renin concentration in the lowest tertile.The PATHWAY-2 study was designed to test the hypothesis that resistant hypertension is a salt-retaining state, and that the best treatment is additional diuretic.The rationale for the extra measurements or intervention that we report here was to link the pathophysiology of resistant hypertension with response to treatment. This link became of particular interest when the primary outcome showed spironolactone to be substantially superior to the alternatives. Although this outcome was scarcely a complete surprise, we had not expected superiority to be exhibited across almost the entire distribution of plasma renin, with the crossover design permitting demonstration that only ten (3%) of 326 patients in PATHWAY-2 had a plasma renin concentration that predicted better blood pressure response to α blockade or β blockade than to spironolactone. It seems reasonable now to conclude that resistant hypertension, as previously suspected,One of the best measures of sodium balance is plasma renin, as shown by the dose-related, several-times increases in plasma renin caused by each of the diuretic treatments in PATHWAY-3.Aldosterone secretion is normally suppressed when renin is low, unless there is autonomous aldosterone production—eg, from an aldosterone-producing adenoma. This aldosterone suppression is apparent during acute salt loading, in cross-sectional studies of dietary sodium intake, in some of the rare monogenic causes of hypertension, and in patients whose low-renin hypertension is due to derivatives of naturally occurring mineralocorticoids.−1 per mU/L−1 is equivalent to a positive saline suppression test, because all patients at entry to PATHWAY-2 were already treated with maximum-tolerated doses of RAS blocker. At most, nine patients might have been excluded from PATHWAY-2 if entry had (implausibly) required two ARR estimations in all screened patients and follow-up confirmatory tests when ARR was higher than 60·94 pmol/L−1 per mU/L−1.The absence of this triad could be anticipated from the eligibility criteria for PATHWAY-2. Yet, despite our exclusion of patients with known or suspected secondary hypertension, even the more conservative of our estimates for primary aldosteronism frequency (10%) exceeds the prevalence of 99 (5·9%) of 1672 unselected patients with hypertension who were recruited from primary care (like most patients in PATHWAY-2), and is similar to the 126 (11·2%) of 1125 newly diagnosed patients referred to specialist clinics.However, the criteria for suspecting and diagnosing primary aldosteronism are likely to miss many of the zona glomerulosa subtype of aldosterone-producing adenomas. Their responsiveness to angiotensin and frequent gain-of-function mutations in an L-type calcium channel−1)−1 is similar to the proportion of unselected patients with hypertension who have an apparently normal ARR but develop acute hyperaldosteronism on stress  or ultra-low dose (30 ng) of adrenocorticotropic hormone.−1)−1 had lower accuracy; however, some variation is unsurprising because ARR itself has no single, universally agreed threshold.We have therefore reported an analysis independent of ARR, which points to a substantially higher upper estimate for prevalence of primary aldosteronism in patients with resistant hypertension than the 10% estimated by ARR. Acute changes in aldosterone concentrations can result in dramatic changes in urine sodium-to-potassium ratio.What practical role, then, do we now envisage for the assessments and interventions reported here? The non-invasive haemodynamic measurements were previously proposed as a device for selecting the best treatment in resistant hypertension.As for the increased awareness of primary aldosteronism as a potentially preventable or curable cause of resistant hypertension, possible investigations and treatments in selected centres and patients will probably vary greatly, as will what can be more widely recommended on the basis of available clinical and health economic evidence. Prospective evaluation of sodium-to-potassium ratios might allow their use as an initial screening filter. Management of primary aldosteronism is rapidly changing as less invasive modalities become available for diagnosis and treatment of functional adenomas.Our study has some limitations. By design, only some of the patients in PATHWAY-2 participated in the various substudies. However, baseline characteristics were similar between the cohorts. Prospective power was calculated for the primary outcome in PATHWAY-2, but not for the individual substudies, which were intended to allow prespecified, secondary mechanistic analyses that might help to explain the results of the main study. In our favour, the size of the study proved much larger than necessary to detect the primary outcome, having been powered to detect a difference of only 3 mm Hg between spironolactone and other drugs, at an α of 0·003;We conclude that the mineralocorticoid receptor antagonist spironolactone is an effective treatment of resistant hypertension because resistant hypertension is commonly a salt-retaining condition probably due to inappropriate aldosterone secretion. Amiloride seems to be an effective, well tolerated alternative to spironolactone. Finally, our findings should encourage debate about whether thresholds for diagnosis of primary aldosteronism should be reconsidered in patients presenting with resistant hypertension, and about the possibility of earlier diagnosis of primary aldosteronism to prevent development of resistant hypertension.