Cardiovascular disease (CVD) is a common human disease with a large number of patients. Vasoactive drugs have a good effect on the contraction and expansion of blood vessels, which can provide certain help for the management of cardiovascular diseases. However, the clinical care of cardiovascular disease has always been based on the superficial resistance level of body fat, weight, and so on, which is unfavorable for the real recovery of patients with cardiovascular disease. This article aims to quantitatively evaluate the effects of clinical care based on vasoactive drug therapy and intrinsic factors of cardiovascular disease. For the treatment of vasoactive drugs, this paper selects the principle of action of the adrenal hormone to judge and analyze the expansion and contraction of the cardiovascular disease. For the clinical nursing of patients with cardiovascular disease, based on multivariate logistic regression, this paper selects internal factors such as age and blood pressure to model the nursing effect. Experiments have shown that the logistic regression model established in this paper can evaluate well the recovery effect of patients with cardiovascular disease. The AUC value of the model reached around 0.9. This showed that the clinical care of patients with cardiovascular disease can not only rationally judge the recovery effect through the model but also adjust the physical and mental conditions of patients with cardiovascular disease according to the coefficients of the model to achieve the best recovery effect. Atherosclerotic cardiovascular and cerebrovascular diseases are one of the most common chronic diseases. Strengthening the research on the pathogenesis and prevention of atherosclerosis is the present focus of medical research. Modern medicine believes that atherosclerosis is the common pathological basis of atherosclerotic cardiovascular and cerebrovascular diseases in different parts of the world. It can be seen that they are diseases of the same origin with different diseases. From the perspective of treatment, it reflects the characteristics of the “same treatment for different diseases” in traditional Chinese medicine. In fact, atherosclerosis can be both a disease and pathogenesis from different perspectives. From a local point of view, atherosclerosis is a process in which various pathogenic factors lead to local damage and antidamage of arteries, and it is a disease for the arteries themselves. On the whole, there is no obvious stenosis of the vascular lumen in patients with early atherosclerosis. When the hemodynamics is not affected, there are often no obvious clinical manifestations. Only when lumen stenosis affects organ perfusion will there be corresponding clinical manifestations. At this time, atherosclerosis is the pathogenesis. Vascular endothelium all over the body is affected by the same risk factors in the blood, and the final morphology, lipid deposition, cytokine expression, and so on are all localized rather than systemic. Therefore, it is still a big problem to study the mechanism of why certain parts are prone to atherosclerosis. Modern medicine now recognizes that plaque-prone parts are related to the hemodynamic differences of blood vessels in different parts and the inherent heterogeneity of blood vessels in different vascular beds. Therefore, research on vasoactive drug therapy and clinical nursing of patients with cardiovascular disease is necessary.Atherosclerosis, cerebral infarction, myocardial infarction, etc., are common cardiovascular diseases in humans. Due to the high incidence of these diseases and the harm of manuscripts, many scholars have studied them. Estruch et al. reanalyzed data related to cardiovascular disease. His research showed that supplementing the Mediterranean diet with extra virgin olive oil or nuts for the primary prevention of cardiovascular disease has a good effect . MarventVasoactive drugs are important antishock chemical drugs, and there are many types and effects of them. There are also many studies on them by related scholars. Al-Shukri et al. explored the effects of vasoactive drugs on bladder wall ischemia and its role in the pathogenesis of OAB . GiffordIn this paper, active learning and regression models are used to model the care of cardiovascular disease. Different from machine learning algorithms, active learning algorithms can proactively discover the most valuable markers from the latest samples for experts to keep the learner model up-to-date with current disease trends. Moreover, the discovery of some new risk factors through active feature sampling has important implications for clinical diagnosis and general medical care. Especially in the clinical nursing effect of patients with cardiovascular disease, the rational and digital nursing effect is the key factor in judging the nursing effect.Vasoactive drugs are drugs that achieve the purpose of antishock by regulating the vasomotor state, changing vascular function, and improving microcirculation blood perfusion, including vasoconstrictors and vasodilators. Vasoactive drugs are mainly used in the adjuvant phase of treatment, and normal blood flow acts on endothelial cells as lamellar shear stress. On the other hand, in atherosclerotic-prone sites, the shear stress exerted on endothelial cells by disturbed blood flow is reduced. Studies have found that abnormal blood flow shear stress can accelerate the process of atherosclerosis, and experimental evidence has shown that changes in blood flow shear stress can affect the structure and function of endothelial cells and smooth muscles, which leads to the deposition of mononuclear macrophages and LDL under the vascular endothelium. Common vasoactive drugs are shown in Statins are currently the most widely used vasoactive drugs for the treatment of atherosclerosis. It can inhibit the reduction of hydroxymethylglutaryl-CoA reductase, block the synthesis of cholesterol ester, and finally achieve the effect of reducing blood lipids and preventing AS . In addiAngiotensin-converting enzyme inhibitor (ACEI) and angiotensin receptor blocker (ARB) can stimulate the expression of platelet-derived growth factors and promote the proliferation of vascular smooth muscle cells because of angiotensin II, thereby leading to atherosclerosis . StudiesCVD is a relatively prevalent chronic disease in China. Especially in recent years, under the influence of factors such as population aging, dietary structure, and pollution, the incidence rate has increased. CVD has great harm to human health, and unhealthy behaviors can easily lead to the occurrence of cardiovascular diseases, as shown in According to the report, the number of CVD patients in China is about 300 million. One person can die from the disease in about 10 seconds, and the mortality rate is increasing year by year, as shown in The cost of late-stage CVD treatment is high, and both the total cost of medical visits and the average cost of each medical visit have risen sharply in recent years. According to 2013 statistics, the total cost of several CVDs such as intracranial hemorrhage, acute myocardial infarction, and cerebral infarction reached 19.238 billion, 11.47 billion, and 39.808 billion yuan, respectively. The average annual growth rates in recent years have reached 19.86%, 33.46%, and 25.37%, respectively, as shown in In view of the present situation of CVD in China, it is urgent to carry out research work to delay the progression of the disease and reduce the incidence. As a chronic disease, CVD has a slow onset process, a long incubation period, and many modifiable pathogenic factors, leaving enough time for the early prevention and treatment of CVD . Based oIn the process of health management, the risk prediction of CVD is very important. The main functions include the following aspects: (1) By combining quantitative and qualitative analysis of the risk level of each factor and the probability of future incidence, the triage management of the assessed objects can be realized. Interventions are provided by category. A personal health plan is created by intervention. CVD improvement is monitored as planned. Then, the improvement results are evaluated. Relying on this method, the scarce medical resources can be optimally allocated again, and the use of resources can be made more reasonable; (2) by predicting and quantifying the size of the individual's risk of disease, it is helpful to promote the assessed subjects to improve their self-management awareness and mobilize their enthusiasm to fully participate. It can fundamentally alleviate the current dilemma of “seeking a doctor after illness” in the treatment of chronic diseases and change passive treatment to active health management, which is of great significance for alleviating CVD events.yi=0 (no disease) and yi=1 (disease) are used as dependent variables.Logistic regression explores the mapping relationship between CVD risk factors (variables) and the occurrence of CVD (dependent variables) and solves the regression parameters to establish a probabilistic mathematical formula for quantitative probabilistic prediction of novel homogeneous risk factor combinations , 19. LogA is a continuous dependent variable yi∗ with a value of . Setting a critical value c (such as c = 0), yi represents the actual observed dependent variable results. Then, the following can be obtained:It is assumed that the occurrence of event yi∗ > 0, then yi=1, represents event A.When yi∗ < 0, then yi=0, represents event A.When yi∗ is linearly related to the variable xi, as shown as follows:.It is assumed that the dependent variable A is P, the following formulas can be obtained:Supposing the probability of occurrence of εi is the error term, which obeys the logistic distribution. According to the pairwise property of logistic distribution, formula  is the cumulative distribution function of the error term εi. According to its characteristics, the following formula can be obtained:In formula , F(.) isP is (0 and 1), which ensures that the estimated probability of the model is between (0 and 1)  is obtained through the following formulas:The partial derivatives of parameters  formula  are calck independent variables, there are k + 1 equations. The equations are combined and calculated by Newton–Raphson iteration. Finally, the maximum likelihood estimates of α and β are obtained. Then, they are substituted into formula (Formulas  and 18)18) are l formula  to estabThe risk factors of CVD vary according to the characteristics of population, race, living environment, dietary habits, and so on, so there are differences in the selection of risk factors in traditional CVD prediction models. The determination of CVD risk factors should meet the following criteria: (a) They are universal. That is, the factors that exist in most CVD patients; (b) they have a close contact. They can individually affect the occurrence and development of CVD; (c) they have significant effects. The risk of morbidity can be reduced after interventional treatment and control.According to the above criteria, with the diversification of research techniques, more risk factors have been discovered and confirmed. Currently recognized CVD risk factors are shown in In 2; application of osmotic dehydration; and management of depth of anesthesia, body temperature, blood sugar, and others. In order to eliminate the interference of these common problems on the experimental data as much as possible, during the research process, these indexes were controlled at the same level in the two experimental groups. Target-controlled infusion (TCI) was used to maintain the same plasma concentrations of anesthetics during discussion and surgery. The intraoperative depth of anesthesia (BIS) was controlled at the same level. Muscle relaxants were administered at the same induction dose (mg/kg) and maintenance dose .During induction of anesthesia, severe choking reactions caused by laryngoscope and endotracheal intubation should be avoided. During recovery from anesthesia, the stress response to the airway in the state of tracheal extubation or tracheal tube retention should be suppressed. After opening the skull, brain relaxation should be maintained to facilitate surgical operations, and patient agitation or circulatory fluctuations caused by intraoperative surgical operations should also be suppressed. Several key issues in the management of anesthesia for induction neurosurgery were shared by both the groups, including the control of intracranial pressure/brain relaxation; fluid infusion; maintenance of blood volume and circulation stability; management of PaCOThe present clinical view is that the autoregulatory response of the brain tissue to a drop in blood pressure may be impaired after acute central nervous system injury, especially after brain injury and subarachnoid hemorrhage. Blood flow to some of the brain tissues is significantly reduced. Therefore, cerebral perfusion pressure should be maintained at normal or even higher than normal levels during such a surgery. Secondly, the brain tissue is compressed when the distractor is used during the operation, and the local compression of the brain tissue will reduce its effective perfusion pressure. The intraoperative blood pressure fluctuation range in both the study groups remained within 20% of the baseline value. Vasoactive drugs were given according to the situation during the operation, and the heart rate was maintained at 50–120 beats/min.A retrospective cohort study of 187 patients with chronic cardiovascular disease showed that although 93% of patients had elevated lactate levels, the mean level was only 4.2 mmol/L, with a wide range (0.2 to 19 mmol/L). There were also studies showing that lactate is not reliable in assessing tissue ischemia in patients on epinephrine because epinephrine itself can cause hyperlactatemia. Only three patients in this study were given epinephrine, but their lactate was not elevated. Compared with the EN tolerance group and the EN intolerance group, the lactate increase ratio in the EN intolerance group accounted for about 86.9%, which was significantly higher than that in the EN tolerance group (49.3%). The dosage of vasoactive drugs was also higher in patients with EN intolerance. It was considered that this may be related to the degree of tissue hypoperfusion and hypoxemia. It can be seen that although it cannot be determined that the increase of lactate is directly related to the EN nutritional tolerance, lactate can reflect intestinal perfusion to a certain extent.In addition, critically ill patients receiving vasoactive drugs should be monitored daily for bowel sounds and bowel movements, as decreased bowel sounds or bowel movements may be early indicators of bowel ischemia. In this paper, there was no statistical difference between the tolerance group and the intolerance group in defecation, but clinicians should be vigilant about the symptoms of gastrointestinal intolerance in patients. When vasoactive drugs are used for EN complications, the most serious complication is NOBN. Further aggravation of intestinal microcirculation ischemia, mucosal damage, or local inflammatory response increases the risk of developing NOBN. The reason may be that the metabolic process of enteral feeding increases the energy demand of intestinal epithelial cells, and vasoactive drugs cause splanchnic hypoperfusion through the vasoconstriction effect caused by sympathetic nerve excitation. In this case, the mucosal layer preferentially receives blood perfusion, while the submucosa, muscularis, and serosa are relatively underperfused. Hypoperfusion is a precursor to intestinal necrosis and may be associated with mucosal inflammation and injury, which can be exacerbated by reperfusion. Studies have shown that NOBN associated with EN has a higher mortality rate than other causes of mesenteric ischemia.Vasoactive drug use and CAG were performed by experienced cardiologists. Two nonparticipating cardiovascular intervention personnel read independently, and the results were taken as the mean of both. According to the CTFC results, if the CTFC value of any one or (and) several coronary vessels is greater than or equal to 27 frames, the phenomenon of coronary slow blood flow can be considered. In patients with coronary slow blood flow confirmed by CAG, real-time vital signs of ECG monitoring equipment were recorded after the first coronary angiography. The patients were then given musk Tongxin-dropping pills to be sublingually administered. For patients with slow absorption, the drug can be gently crushed with teeth and mixed with a little normal saline to accelerate the absorption. Studies have shown that under normal circumstances, the dropping pills can be completely melted and absorbed under the tongue for 3–8 minutes. This paper took a median of 5 min. 5 min later, the coronary angiography was performed again, and the blood pressure and heart rate after taking the drug were recorded. The CTFC values after taking the drug were collected in the same way. Whether the patient had discomfort after taking the medicine during the operation was observed. Blood was drawn within 24 hours after coronary angiography for retesting of the liver and kidney function. Coronary slow blood flow is one of the more common phenomena in coronary angiography, which is characterized by no obvious vascular structural lesions in coronary angiography but slow blood flows in distal blood vessels and delayed myocardial perfusion. Since the phenomenon was discovered and reported in 1972, it has become a research hotspot. Due to its particularity, it can be directly identified by the naked eye in angiography, so direct coronary or intravenous administration can directly observe the improvement of blood flow in angiography. In coronary angiography, the mean CTFC value of slow blood vessels was reduced from 43 frames (29–73 frames) to 32 frames (20–60 frames) after injection of isosorbide dinitrate. After further intracoronary injection of a 1 mg nicorandil needle, the CTFC value of coronary blood flow further decreased, reaching 25 frames (12–34 frames). Finally, the CTFC value of coronary angiography returned to the original level.α, β1, ⋯, βp) and establish an expression model. The independent variable data of the test group (the remaining instances) were substituted, and the obtained prediction results were compared with the real labels to find the correct rate; (b) dummy variables were set for multicategory independent variables, and logistic regression (denoted as Dv-Logistic) was performed on the processed data according to the experimental procedure. The model accuracy obtained from the two experiments was compared.In order to prove the problems existing in the regression model in the face of complex factors and the effectiveness of the solutions, two parts of the experiment were designed by taking logistic regression as an example: (a) Direct logistic regression experiments. The data of the training group (80% of the instances in each dataset) were used to solve the value of the regression parameter  and Heart Disease Database, in the UCI machine learning library were selected. Statlog(Heart) contained 270 groups of instances. The Heart Disease Database contained 820 instances. Each instance had 76 attributes. The same attributes and labels as Statlog (Heart) were extracted, and the missing data were preprocessed by the mean method. The attributes of the two datasets included continuous, binary, ordered multicategory, and unordered multicategory variables, as shown in The experiments of logistic regression and setting dummy variables were implemented on the SPSS21.0 software, and the software running environment was Windows 7 32-bit operating system. The configured CPU was Intel(R) Core (TM) i5M460@2.53 GHz. According to the analysis method of logistic regression in SPSS, firstly the original data were used to carry out a single factor regression experiment in SPSS to eliminate unnecessary factors. Then, a direct regression experiment was performed on the culled raw data. Finally, dummy variables were set for multicategory factors into binary factors, and regression experiments were performed in SPSS. Using the intuitive result presentation interface in SPSS, the two experiments were recorded separately.First, in order to reduce the computational complexity, a single-factor unconditional logistic regression analysis was performed on the 13 attributes in the original dataset. The results are shown in Figures As shown in P value refers to the degree of correlation between the factor and the outcome of the event, usually with P < 0.05 indicates that the attribute is statistically significant. Therefore, the two factors of Trestbps and Fbs in the two datasets were not meaningful and were eliminated. The OR value is the odds ratio, which is an accurate estimate of the relative risk. If OR > 1, the factor is a risk factor. If OR < 1, the factor is a protective factor.As shown in As shown in Through the analysis of the problem of the logistic regression model oriented to complex factors, according to the conditions and methods of dummy variable setting. Dummy variables were set for multicategory factors in the dataset, and they were turned into binary variables. Among the attributes, Cp, Restecg, Slope, and Thal were the four-category disorder, three-category disorder, and three-category order variables, respectively. The number of dummy variables was 3, 2, 2, and 2 respectively, and the control coding method was selected, as shown in By setting dummy variables, the number of variables in the model was increased to 17. Experiments were conducted on the altered dataset. The Dv-Logistic model was established and substituted into the test data. The experimental results were compared. The experimental results of the logistic and Dv-Logistic models on the two datasets were compared and analyzed.The receiver operating characteristic curve (ROC) was drawn according to the classification prediction results. By taking the sensitivity and 1-specificity indexes as the ordinate and abscissa, respectively, the sensitivity and specificity were integrated into one index, which avoided the influence of morbidity in CVD prediction and was a commonly used model performance evaluation index in CVD prediction. AUC is an indicator to measure the area under the ROC curve. The larger the value is, the closer the ROC curve is to the upper left corner, and the more reliable the model is. If the AUC is lower than 0.5, it is of no practical significance. If the AUC is between 0.5 and 0.7, the model has lower performance. If the AUC is between 0.7 and 0.9, the model has good performance. If the AUC is greater than 0.9, it proves that the model has high performance.The statistical logistic model and Dv-Logistic model were used to compare the prediction results of the two datasets with the corresponding real label values to draw ROC curves, as shown in For the evaluation of the prediction ability of the model, in addition to using the ROC curve to display it visually, it is also necessary to compare the degree of fit between the category of the prediction result and the corresponding real label value, that is, through comprehensive evaluation such as sensitivity, specificity, and accuracy. In CVD prediction, it is explained as follows: sensitivity (Se): the ability to correctly predict the disease; specificity (Sp): the ability to correctly predict the absence of disease; positive predictive rate (Pp): the proportion of cases that are predicted to have the disease; negative predictive rate (Np): the proportion of instances that are predicted to be not diseased; and accuracy rate (Ac): the proportion of correctly predicted instance categories in all instances.Statistics and calculation of the test results of the logistic and Dv-Logistic models on the two datasets were carried out for comparative analysis, as shown in By analyzing the comparison results in Using complex factors for the prediction of CVD can make the model-fitting results close to the real nursing situation, which is of great significance for formulating targeted interventions and improving the efficiency of CVD management. The main line of this paper is to study CVD prediction oriented to complex factors so that the prediction model can incorporate complex factors with high prediction accuracy and stability. For the establishment of the model, the importance of complex factors in CVD prediction is first analyzed. Focusing on the complex factor-oriented CVD prediction problem, the calculation process of the regression prediction model is first studied. The specific reasons why complex factors cannot be used in traditional CVD prediction models were analyzed from the model mechanism, and then, dummy variables were used to change the data format of complex factors to adapt to the regression model. The experimental results showed that complex factors cannot be directly used in traditional CVD regression prediction models. Restricted by various conditions, the prediction model established at each stage can only be tested by the data in the machine learning database, and the amount of data are relatively small. The next step is to collect more real CVD data containing complex factors to test and correct and improve the model to further explore its practical value, comprehensively considering the parallel computing problem when the model is applied in the system.


ABCB1  and one in ABCG2 (rs2231142) and the imatinib plasma trough concentration (Ctrough) was investigated in 33 GIST patients enrolled in a prospective clinical trial. The results of the study were meta-analyzed with those of other seven studies  selected from the literature through a systematic review process. The ABCG2 c.421C>A genotype demonstrated, in our cohort of patients, a borderline association with imatinib plasma trough levels that became significant in the meta-analysis. Specifically, homozygous carriers of the ABCG2 c.421 A allele showed higher imatinib plasma Ctrough with respect to the CC/CA carriers  in 293 patients eligible for the evaluation of this polymorphism in the meta-analysis. The results remained significant under the additive model. No significant association could be described between ABCB1 polymorphisms and imatinib Ctrough, neither in our cohort nor in the meta-analysis. In conclusion, our results and the available literature studies sustain an association between ABCG2 c.421C>A and imatinib plasma Ctrough in GIST and CML patients.Adequate imatinib plasma levels are necessary to guarantee an efficacious and safe treatment in gastrointestinal stromal tumor (GIST) and chronic myeloid leukemia (CML) patients. Imatinib is a substrate of the drug transporters ATP-binding cassette subfamily B member 1 (ABCB1) and ATP-binding cassette subfamily G member 2 (ABCG2) that can affect its plasma concentration. In the present study, the association between three genetic polymorphisms in  The tyrosine kinase inhibitor (TKI) imatinib mesylate is the treatment of choice for the management of chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GIST) ,2 and thDespite the outstanding efficacy of imatinib in CML and in GIST, a considerable portion of patients fails to achieve a stable therapeutic effect. It is estimated that approximately 30% of newly diagnosed CML and 10% of GIST patients develop resistance to imatinib within the first year of treatment, thus presenting an increased risk of experiencing poor survival outcomes .multidrug resistance 1  gene, and the breast cancer resistance protein (BCRP), encoded by the ABCG2 gene. These proteins may play a dual role in the tumor resistance to imatinib. On one hand, the overexpression of P-gP and BCRP in tumor cells increases the tumor detoxification of the drug. On the other hand, as imatinib is a chronically assumed oral drug, P-gP and BCRP expression levels in normal tissue  may affect its plasmatic concentration, potentially leading to under-exposure [Imatinib is a substrate of two efflux proteins, the P-glycoprotein (P-gP), encoded by the exposure .ABCB1 and ABCG2 genes are highly polymorphic and some of the polymorphisms described were reported to affect the expression levels of the encoded proteins. Specifically, for ABCB1, the c.3435C>T (rs1045642), c.2677G>T/A (rs2032582), and c.1236C>T (rs1128503) polymorphisms were reported to lead to ABCB1 mRNA instability, thus leading to reduced protein expression and to the reduced functionality of P-gP in vivo [ABCG2, c.421C>A (rs2231142) is one of the most frequent polymorphisms and was found to be associated with lower protein expression in vitro and in vivo [The >T rs104542, c.267A rs203252, and c. in vivo . ABCB1/ABCG2 polymorphisms and the efficacy of imatinib in both CML and GIST [ABCB1/ABCG2 polymorphisms contribute to the inter-individual variability in treatment efficacy by specifically affecting the imatinib pharmacokinetics has not been clarified. The few studies that have tried to address this point led to unclear findings, leaving unbridged the gap between ABCB1/ABCG2 polymorphisms and imatinib exposure [Several clinical investigations have highlighted the association between and GIST . To whatexposure ,12. ABCB1 c.3435C>T, c.2677G>T/A, c.1236C>T, ABCG2 c.421A>C, and the imatinib plasma trough concentration (Ctrough) in a prospective cohort of 33 GIST patients enrolled within a clinical trial at our Cancer Institute. To further substantiate our findings, we also carried out a meta-analysis of the published literature to quantitatively summarize the impact of ABCB1 c.3435C>T, c.2677G>T/A, c.1236C>T, and ABCG2 c.421A>C on imatinib plasma Ctrough in CML and GIST. In the present study, we investigated the association between As of January 2022, 33 consecutive GIST patients, who met the inclusion criteria for the present study, were considered from those enrolled in the main clinical trial (2017-002437-369) . Hencefotrough in the 33 GIST patients included in the CRO-Aviano Study was 1040.6 ng/mL (IQR: 749.5–1292.4 ng/mL), ranging from a minimum of 255.8 ng/mL to a maximum of 2452.8 ng/mL. All 33 patients were successfully genotyped for the candidate variants and no significant deviation from the Hardy–Weinberg equilibrium (HWE) was observed for any of them. Detailed information on genotype and allele frequency distribution is reported in Average imatinib Ctrough according to ABCB1 and ABCG2 genotypes is shown in trough across different genotypes was observed.The comparison of imatinib CABCB1 variants  showed tendentially higher imatinib Ctrough with respect to heterozygous or homozygous variant carriers. On the other hand, wild-type ABCG2 c.421 CC carriers showed lower, although not significant, mean imatinib Ctrough (1011.9 ng/mL) with respect to heterozygous (1030.3 ng/mL) and variant carriers (1792.8 ng/mL). The impact of the ABCB1 c.3435C>T, c.2677G>T, c.1236C>T haplotype was assessed, but no significant difference was ascertained. Patients bearing the wild-type allele for all three trough for individual genotypes, but the authors provided the data on our request [A total of 75 potentially relevant articles were identified with our initial search strategy. After screening the titles and abstracts of articles, 47 studies were excluded because they were deemed repetitive or unqualified. After reading 28 potentially eligible papers, six studies from the literature met our inclusion criteria ,17,18,19 request . No addiABCB1 c.3435C>T genotype, five (71.4%) studies analyzed the ABCB1 c.1236C>T, four (57.1%) studies analyzed ABCB1 c.2677G>T/A, and five (71.4%) studies analyzed ABCG2 c.412C>A. The mean imatinib plasma Ctrough ranged from 359.3 ng/mL to 2178.4 ng/mL. The characteristics of the included studies are reported in All included studies reported satisfactory quality (MINORS score > 50.0%), with an average of 65.2% (range: 50.0%–87.5%), suggesting that the overall methodological quality of the included studies was from moderate to high .ABCB1 c.3435C>T, c.2677G>T, c.1236C>T, and imatinib Ctrough levels is reported in A summary of random-effect models for the association between ABCB1 c.3435C>T and imatinib plasma Ctrough levels [trough among different ABCB1 c.3435C>T genotypes according to any model (p < 0.01).Seven studies including 649 patients administered with imatinib 400 mg per day were available for the association between h levels ,17,18,19ny model . HoweverABCB1 c.2677G>T and imatinib plasma Ctrough levels [p = 0.05) association between the ABCB1 c.2677G>T genotype and imatinib plasma Ctrough was highlighted by the additive model  with respect to the GT/A carriers  and the TT/AA carriers (1403.9 ng/mL). The same trend was maintained when considering the dominant model, where homozygous carriers of the ABCB1 c.2677 G allele showed lower imatinib Ctrough when compared to the T/A allele carriers   . ABCB1 c.1236C>T and imatinib plasma Ctrough [trough among ABCB1 c.1236C>T genotypes according to any genetic model , dominant (CC vs. CA + AA), or additive (CC vs. CA vs. AA) models. A significant difference in imatinib plasma Ctrough was identified under the recessive (p = 0.04) and additive models (p = 0.04) . The additive model showed that CC carriers had mean imatinib Ctrough (imatinib Ctrough 1177.3 ng/mL) lower than the AC (imatinib Ctrough 1228.4 ng/mL) and the AA carriers (imatinib Ctrough 1463.2 ng/mL).A summary of random-effect models for the association between  Ctrough ,16,19. Tdetected . The fou = 0.04) . Under tTherapeutic failure in CML and GIST due to imatinib resistance is responsible for disease progression and shorter survival perspectives and remains an unmet challenge in clinical oncology. Addressing the complex phenomenon of imatinib resistance can help clinicians to personalize treatments by proposing imatinib dose adjustments or a switch to other therapies.Inadequate exposure to imatinib is one of the leading mechanisms of treatment resistance. In this context, the activity of the efflux transporters P-gP and BCRP plays a pivotal role modulating the quantity of drug reaching the systemic circulation, and hence the tumor cell, as well as the amount of drug that is delivered to the intracellular molecular targets.ABCB1/ABCG2 genotype and treatment clinical outcomes in CML and GIST [trough threshold of 1100 ng/mL and 1000 ng/mL was proposed to guarantee a clinical benefit in GIST and CML, respectively [ABCB1/ABCG2 germline variants on imatinib systemic exposure as a key step to determine the development of resistance. Here, we investigated the impact of the most widely studied ABCB1 c.3435C>T, c.2677G>T/A c.1236C>T, and ABCG2 c.421C>A polymorphisms on the imatinib Ctrough in a prospective cohort of 33 Caucasian GIST patients. To the best of our knowledge, this is the first time that the association between the ABCB1/ABCG2 genotype and imatinib plasma Ctrough has been assessed in GIST. Despite small differences in pharmacokinetic properties between GIST and CML patients, still some variability can be observed as a consequence of liver metastasis or gastric/intestinal surgery affecting GIST patients. Therefore, a thorough and dedicated investigation of factors affecting imatinib disposition in GIST is urgently needed to provide a rationale for dose adjustment [ABCB1/ABCG2 genotype and imatinib plasma Ctrough in GIST and CML.Thus far, most of the published literature has focused on the association between the and GIST ,21,22,23ectively ,25. DespABCG2 c.421A allele and higher imatinib Ctrough with respect to the C allele, which is concordant with the expected effect of the SNP on the protein, and this became statistically significant when meta-analyzed with another three eligible published studies. The studies included in the meta-analysis were small (up to 173 patients), not allowing sufficient statistical power when taken alone. Moreover, the heterogeneity of the ABCG2 c.421C>A minor allele frequency (MAF) across different ethnical groups  can make less evident the effect of the genotype in studies involving a narrow number of ABCG2 c.421 AA carriers. Nevertheless, the possibility to perform a meta-analysis allowed us to demonstrate the presence of a significant correlation between ABCG2 c.421C>A and imatinib plasma Ctrough in CML and GIST patientsIn the CRO-Aviano Study, a trend was highlighted between the ABCG2 and is located on the apical surface of intestinal epithelia cells and on the biliary surface of hepatocytes, where it acts as an efflux transporter. The non-synonymous variant at the coding position 421 at exon 5, entailing a C>A nucleotide transition, is one of the most studied polymorphisms of ABCG2 (rs2231142). The minor allele frequency (MAF) of the variant is equal to 10.3% in the European population, but it reaches 29.7% in the Asian population. The nucleotide switch results in a Gln to Lys substitution at the protein position 141 (Q141L), which has been associated with lower protein expression in breast cancer cell lines [trough was higher in patients with the AA or CA genotype for ABCG2 c.421C>A with respect to the CC carriers (dominant model) in a cohort of 67 Japanese CML patients [ABCG2 c.421C>A  [ABCG2 c.421A allele and higher imatinib Ctrough. Although some studies reported a lack of any possible association between ABCG2 c.421C>A and imatinib Ctrough [ABCG2 c.421C>A genotype might play a key role in modulating imatinib disposition in GIST and CML.BCRP is the protein encoded by ll lines . Intrigull lines , sustainpatients . Moreove < 0.05)  reported Ctrough ,30, takeABCB1 SNPs in imatinib pharmacokinetics. From our data, no significant effect of the ABCB1 analyzed variants and imatinib plasma Ctrough has emerged. The meta-analysis also failed to underscore a significant association between any of the ABCB1 variants and the imatinib plasma Ctrough. Only patients who were heterozygous carriers of the variant T/A alleles for ABCB1 c.2677G>T/A exhibited non-significantly higher imatinib Ctrough with respect to the wild-type patients, under the additive (p = 0.05) or dominant (p = 0.06) models. It must be noted that the herein analyzed ABCB1 polymorphisms, c.3435C>T, c.2677G>T/A, and c.1236C>T, are in strong linkage disequilibrium with each other and have been associated with reduced P-gP expression and functionality [ABCB1 haplotype comprising the three c.3435C>T, c.2677G>T/A, and c.1236C>T variants. The presence of the minor allele in each genotype for the three ABCB1 polymorphisms was previously associated with lower P-gP activity with respect to the wild-type ABCB1 and with a lower imatinib export capacity [More controversial are the results that we obtained both in our study cohort and in the successive meta-analysis on the role of capacity .ABCB1 polymorphism in the meta-analyzed studies prevented us from investigating the impact of the ABCB1 TTT haplotype on imatinib plasma Ctrough, and the single SNP approach could have hindered the actual impact of the ABCB1 haplotype. The lack of information on each single ABCB1 genotype on imatinib disposition and pharmacokinetics showed conflicting results in the published literature, leaving plenty of room for further devoted investigations [trough. Due to the small size of our study cohort, as well as the complex phenomenon of drug–drug and drug–gene interaction, the potential effect of concomitant interacting drugs on imatinib Ctrough was not considered in the present study and remains an issue to be investigated in thorough, dedicated studies. The impact of the igations . It is aigations ,32, and trough and genotypes from most of the corresponding authors prevented us from conducting a pooled analysis on raw data. However, although the impact of ABCB1 on imatinib disposition remains to be further addressed, a clear effect of ABCG2 c.421C>A on imatinib exposure has emerged, suggesting that the genotyping of ABCG2 c.421C>A may be a valuable tool to explain the variability in imatinib pharmacokinetics. As a future perspective, joint collaborations including multiple research groups focused on the present topic to pool data on imatinib Ctrough and the ABCB1/ABCG2 genotype will help to shed light on the actual contribution of transporters’ pharmacogenetics to imatinib disposition.Some limitations of the present study must be acknowledged. First, the small number as well as the small sample sizes of included studies might have obscured our findings. Second, the heterogeneity of ethnic groups and the different analytical methods used to quantify imatinib plasma concentrations could have contributed to the wide inter-study heterogeneity here observed. In addition, the impossibility of retrieving individual imatinib CABCG2 c.421C>A and imatinib plasma Ctrough. The current meta-analysis provides evidence that CML and GIST patients administered with imatinib carrying the homozygous variant of ABCG2 c.421C>A show higher imatinib Ctrough with respect to wild-type and heterozygous patients. This finding indicates the need for a thorough, extensive characterization of genetic variants affecting imatinib transporters in wider study populations and supports the implementation of pharmacogenetics to refine imatinib dose adjustment. In summary, the available studies and our original results presented here support a consistent correlation between Patients who were enrolled at IRCCS Centro di Riferimento Oncologico di Aviano  within a prospective clinical trial (EudraCT number 2017-002437-36) provided signed informed consent at the time of enrollment. The research protocol was registered by AIFA and was approved by the Local Ethical Committee as previously described . All anaThe clinical research protocol had the primary aim to assess the feasibility of the routine therapeutic drug monitoring (TDM) of imatinib and circulating tumor DNA analysis in serial blood samples from GIST patients. Eligibility criteria were as follows: (i) histologically confirmed GIST; (ii) treatment with imatinib > 90 days prior to study entry, regardless of the administration setting; (iii) Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1; (iv) adequate liver, renal and bone marrow function; (v) age ≥ 18; (vi) capability of attending scheduled medical check-ups regularly; (vii) signed informed consent. For the purposes of the herein presented sub-study, patients who met specific additional requirements were selected: (i) administration of imatinib 400 mg daily dose, (ii) concentration of imatinib above the lower limit of quantification .2-EDTA containing tubes at the time of regular medical check-ups, every 3 to 6 months. Plasma was separated by means of centrifugation and stored at −80 °C until imatinib quantification. Genomic DNA was extracted from the harvested buffy coat by means of the GeneJET Whole Blood Genomic DNA Purification Mini Kit  and quantified with a Quantus Fluorometer . Genomic DNA was stored at 4 °C. ABCB1 and ABCG2 were analyzed by means of targeted next-generation sequencing (NGS). Sequencing libraries were prepared starting from 100 ng of genomic DNA using a custom hybridization-based NimbleGen SeqCap EZ Choice Library  targeting the UTRs and the coding sequences of 60 cancer-related genes, according to the NimbleGen SeqCap EZ Library SR User’s Guide v3.0 . Genomic DNA was enzymatically fragmented for 15 min at 37 °C, end-repaired, A-tailed and ligated with Illumina-indexed adapters. Ligated libraries were size-selected by means of Agencourt AMPure XP Beads  to retain fragments ranging between 300 and 350 bp and amplified in 12 PCR cycles. Final libraries were quantified by means of the Quantus Fluorometer  with the QuantiFluor dsDNA Dye  and the fragment size analysis was performed using the Agilent 4200 TapeStation  with High-Sensitivity D1000 ScreenTape. Pooled libraries were obtained by putting together 45 ng of each sample that was amplified in the regions of interest by using the SeqCap EZ Choice Library , followed by 7 PCR cycles. At the time of sequencing, libraries were denatured with fresh NaOH 0.2 M and diluted to a final concentration of 10 pM. Generated FASTQ files were processed using the Variant Studio software , for variants’ annotation. First, 15 mL of blood was routinely collected as a per-protocol methodology in Km/z 494.4 > 394.2 for imatinib and m/z 502.4 > 394.2 for imatinib-D8, used as an internal standard. The developed method was validated according to FDA and EMA guidelines for the validation of bioanalytical methods, evaluating the linearity, recovery, limit of detection, limit of quantification, matrix effect, inter- and intra-day precision and accuracy, selectivity, stability and reproducibility. To guarantee the homogeneous quantification of imatinib Ctrough, blood samples were possibly collected 24 h after the last imatinib administration. If imatinib had not been administered exactly 24 h prior to blood collection, the following formula, previously validated by Wang et al. [trough:Quantification of imatinib was performed using an LC-MS/MS instrument consisting of a Prominence LC-20AD UFLC XR  and an API 4000 QTrap mass spectrometer . Imatinib was quantified after protein precipitation by means of a methanol-based extraction method. Imatinib was separated on a Synergy Fusion RP C18 chromatography column 4 μm, 50 × 2.0 mm, coupled to a C18 precolumn . Elution was performed in gradient-mode chromatography. The mass spectrometer was equipped with an electrospray ionization (ESI) source interface operating in positive ion mode. The biological samples were analyzed in Selected Reaction Monitoring mode. Quantifications were performed using the following transitions: g et al. , was useC = measured drug concentration, T = hours from the last drug administration, T1/2 = drug plasma half-life (18 h).The samples collected up to five hours or more than thirty-five hours from the last imatinib administration were excluded from the analysis as they were outside the algorithm’s range of linearity.ABCB1” OR “ABCG2” OR “transporters” OR “pharmacogenetics”. No time restrictions were applied. Two authors (CDF and EDM) independently screened all titles and abstracts generated by the search and then evaluated the full texts of relevant articles identified against the inclusion criteria  checklist . PubMed,criteria . A thirdtrough at the steady state; (iv) studies reported the association between individual polymorphisms in ABCB1 and/or ABCG2 and imatinib plasma Ctrough. Non-English studies were excluded. Studies containing duplicated data from previously published works were excluded, as well as review articles, case reports, editorials and letters. Two authors  independently assessed the quality of the included studies according to the Methodological Index for Non-Randomized Studies (MINORS) criteria [Studies were included in the analysis if they met the following criteria: (i) the study included patients administered imatinib for more than one month for the management of GIST or CML; (ii) patients were treated with an imatinib standard dose of 400 mg/die; (iii) studies reported imatinib plasma Ccriteria . MINORS ABCB1/ABCG2 genotypes and imatinib plasma Ctrough was assessed by the non-parametric Kruskal–Wallis test. Mean imatinib plasma Ctrough and corresponding standard deviation by genotype to be used in the meta-analysis were retrieved from selected articles or our present case series. Dominant and recessive models were evaluated combining mean imatinib plasma Ctrough and corresponding standard deviation of heterozygous or variant carriers for the former, and of wild-type and heterozygous carriers for the latter. The pooled mean imatinib plasma Ctrough and corresponding 95% confidence interval (CI) were calculated according to random-effects models of DerSimonian and Laird; statistical heterogeneity among studies was evaluated using the I² and τ2 statistics [trough with corresponding 95% CI. Statistical significance was claimed for p < 0.05 (two-sided). Clinical data were presented as absolute frequencies and percentages and as median and range as appropriate. Chi-squared analysis was used to test for genotype deviation from Hardy–Weinberg equilibrium. In the patients included in the CRO-Aviano Study, the association between atistics . The res


Past studies reported a significant contribution of a prothrombotic state to the development and progression of target organ damage in hypertensive patients. Stiffening of arterial vessels is associated with aging and hypertension, and additional factors could contribute to this process. This study was designed to examine the relationships between arterial stiffening and the hemostatic and fibrinolytic system.In 128 middle-aged, nondiabetic, essential hypertensive patients without major cardiovascular and renal complications, we measured coagulation markers that express the spontaneous activation of the hemostatic and fibrinolytic system and assessed stiffness of the arterial tree by measurement of the carotid/femoral pulse wave velocity (cfPWV) and pulse wave analysis with calculation of the brachial augmentation index (AIx).Levels of fibrinogen (FBG), D-dimer (D-d), and plasminogen activator-inhibitor 1 (PAI-1) were significantly higher in patients with PWV and AIx above the median of the distribution. FBG, D-d, and PAI-1 were significantly and directly related with both cfPWV and AIx, and multivariate regression analysis indicated that the relationships of D-d and PAI-1 with both cfPWV and AIx and of FBG with AIx, were independent of age, body mass index, severity and duration of hypertension, use of antihypertensive drugs, blood glucose, and plasma lipids.In middle-aged, uncomplicated, nondiabetic patients with essential hypertension, spontaneous activation of plasma hemostatic cascade and impaired fibrinolysis is significantly and independently associated with stiffening of the arterial tree. Seminal work that was published in the early 1960s described the structural changes of aorta and other elastic vessels in response to blood pressure increase , and artIntrinsic hyperactivation of the hemostatic system characterizes the prothrombotic states and is a well recognized risk factor for cardiovascular events in the general population , 16 and The possible relevance of coagulation factors for stiffening of large elastic arteries has been the subject of previous investigations. These investigations were almost exclusively focused on fibrinogen because its circulating levels affect plasma viscosity and, by affecting the rheological properties of blood, might contribute to arterial structural and functional changes . InconsiIt is well known that thorough functional investigation of the hemostatic cascade and fibrinolytic system requires assessment of many other markers in addition to fibrinogen , and dat2; pregnancy; secondary hypertension; 24-h creatinine clearance lower than 30 ml/min/1,73 m2; diabetes; use of lipid-lowering, antiplatelet, anticoagulant drugs and any type of drugs that could interfere with the hemostatic system; history of recent illness and acute or chronic inflammatory conditions; history of cerebrovascular, ischemic heart, or peripheral artery disease. Causes of secondary hypertension were ruled out according to current guidelines  by the same trained operator who, during examination, was unaware of the patients’ clinical characteristics. Arterial stiffness was assessed by pulse wave analysis with calculation of the AIx and by measurement of the cfPWV.Continuous tracking of the brachial artery pressure waveform was obtained with standard methodology , and theAssessment of the cfPWV implies the measurement of the delay between the upstroke of the carotid and femoral artery pulse waves as detected by tonometry . To thist-test for unpaired groups and the two-sample Wilcoxon rank-sum test were used for the comparison between 2 groups with normal or skewed variable distribution, respectively. The Pearson’s Chi-square test was used to compare frequency distributions. The relationships between different variables were examined by linear regression analysis, and correlation was expressed by the correlation coefficient r. In this analysis, variables with skewed distribution were log transformed. Multivariate regression analysis was performed to determine which variables were independently associated with the AIx and cfPWV. In this analysis, variables were sequentially entered in a stepwise model according to the statistical strenght observed in the univariate analysis. A p value of <5% was considered to indicate statistical significance. All data analyses were performed using Stata 12.1 .The Kolmogorov–Smirnov test was used to determine normality of distribution of the variables included in the study. Normally distributed variables are expressed as mean ± standard deviation and skewed variables as median (interquartile range). Categorical data are expressed as absolute number and percentage. The Student’s Cross-sectional data of 128 hypertensive patients  were included in analysis. Forty-seven (37%) of 128 patients had never been treated with anti-hypertensive drugs. The remaining 81patients (63%) were treated with angiotensin-converting enzyme inhibitors or angiotensin II-receptor antagonists (37%), calcium-channel blockers (34%), diuretics (27%), beta-blockers (23%), and alpha-blockers (5%).Coagulation parameters are summarized in Univariate correlation analysis showed that AIx was significantly and directly related with age, total and LDL-cholesterol, and plasma fibrinogen, D-dimer, and PAI-1 . cfPWV wMultivariate regression models were applied using either AIx or cfPWV as the dependent continuous variable and including variables identified in the univariate correlation analysis as covariates. In this analysis, plasma fibrinogen, D-dimer, and PAI-1 were included separately. As shown in Arterial stiffening anticipates major cardiovascular events in hypertension and many factors, in addition to high blood pressure, can contribute to vascular changes in hypertensive patients. This study was conducted in a highly selected population of hypertensive patients who were free of major cardiovascular and renal complications, testing the hypothesis that a prothrombotic state is associated with arterial stiffening. Results demonstrate that arterial stiffness, as assessed noninvasively by both PWA and cfPWV, is directly related with plasma fibrinogen, D-dimer, and PAI-1 levels. This relationship is independent of age, sex, BMI, hypertension severity and duration, use of antihypertensive drugs, smoking, and plasma lipid levels, suggesting that a prothrombotic state might contribute to functional arterial changes occurring in patients with high blood pressure. Alternatively, in hypertensive patients, stiffening of the arterial tree might activate the hemostatic system leading to a prothrombotic state.For a long time, arterial stiffening has been considered just a consequence of aging. This was because, during aging, unrelenting chopping and rearrangement of the elastic layers occurs in the large arterial vessels leading to vascular stiffening . BesidesNon-invasive methods are widely employed for definition of arterial stiffness. In the last decades, assessment of the cfPWV has become extensively popular and because of its capacity to define the distensibility of large conduit arteries it was considered a sort of gold standard. Additional methods that are based on recording and analysis of the blood pressure waveform such as the AIx explore the distensibility of the peripheral arterial tree  and are Increased intrinsic activity of the hemostatic cascade and impaired fibrinolysis were reported in patients with hypertension , 49 and The relationship between coagulation variables and arterial stiffness was investigated in previous studies. Early observations obtained in healthy middle-aged women did not report any association between PWV and plasma fibrinogen . Higher Limitations to the present study should also be considered. The cross-sectional design limits the possibility to establish a causal relationship between the prothrombotic state and arterial stiffness or viceversa, although independence of this relationship from confounders in the multivariate analysis would suggest so. Also, the possibility that a prothrombotic state and arterial stiffening causally affect one another cannot be excluded. Use of a selected clinic sample of hypertensive patients might limit the possibility to extend the present findings to a broader context. Inclusion of a significant proportion of patients who were treated with antihypertensive drugs might have affected the results although possible interference of treatments on the results were ruled out in the multivariate analysis. Last, calculation of the pulse wave travel distance as the sum of the distance carotid-sternal notch plus the distance sternal notch-femoral pulsation might have overestimated the aortic path length as compared to other suggested methods for PWV assessment .Identification of conditions that in addition to high blood pressure could contribute to the development of subclinical arterial damage is crucial for effective prevention of major complications in patients with hypertension. Arterial stiffening is an unrelenting process related to aging that is accelerated in patients with high blood pressure and predicts cardiovascular morbidity and mortality. Because of previous evidence on a role of a prothrombotic state in the development and progression of hypertension-related organ damage, we examined the relationship between arterial stiffness and variables of the hemostatic and fibrinolytic systems. This is the first study to report an independent association of arterial stiffening with activated hemostatic cascade and impaired fibrinolytic system in nondiabetic hypertensive patients who were free of major organ complications. These results could have important clinical implications opening new paths to the possibility to prevent hypertensive vascular changes. Detection of changes in the hemostatic system could be useful to guide physicians toward more aggressive control of blood pressure and additional risk factors. Future studies will have to test the effects of interventions on the hemostatic system on the development and progression of hypertension-related vascular abnormalities.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.The studies involving human participants were reviewed and approved by Institutional Review Board - Department of Medicine. The patients/participants provided their written informed consent to participate in this study.GB, LS, and CC: conceptualization and design. GB, AP, LB, AV, NB, CV, LS, and CC: acquisition of data and data analysis. GB, LS, and CC: writing the original draft. AP, LB, AV, NB, and CV: writing, reviewing, and editing. All authors approve the final version of the manuscript, including the authorship list and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.This work was supported by a research grant of the PierSilverio Nassimbeni Foundation to LS and CC.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Restriction of sodium intake is routinely recommended for patients with chronic kidney disease (CKD). Whether or not sodium intake is associated with the progression of CKD and mortality remains uncertain. We evaluated the association between urinary sodium excretion (as a surrogate for sodium intake) with the occurrence of renal failure and mortality in patients with non-dialytic CKD.We conducted a retrospective study of patients followed at a CKD clinic care hospital from October 2006 to March 2017. Adult patients with non-dialytic CKD were included. Using a time-to-event analysis, we examined the association of urinary sodium excretion as a categorical variable  and the outcomes of interest. The primary outcome was defined as progression to end-stage renal disease requiring any type of renal replacement therapy. The secondary outcome was mortality.Two hundred five patients were included in the study (mean follow up of 2.6 years) with a mean eGFR of 26 (19–41) ml/min/1.73m2. 37 patients (18%) required renal replacement therapy and 52  died. There was association between urinary sodium excretion and need for renal replacement therapy . There was no association between urinary sodium excretion and mortality in adjusted models.Moderate sodium intake was associated with a lower risk of renal failure. Chronic kidney disease (CKD) affects about 10% of the adult population –5. The CThe treatment aims is attenuate the progression of CKD interventions on modifiable factors: to increase survival, preparing the patient for a possible renal replacement therapy, and improving the quality of life . ClinicaCurrent guidelines recommend a sodium consumption of 2.4 g/day for the adult population –17. The These mechanisms suggest the relationship between sodium intake with renal outcomes and mortality should be linear. Although several studies have shown association between increased sodium intake with CKD progression , 24, 26 In view of the heterogeneity of the published results, the aim of our study was determine if urinary sodium excretion is associated with mortality and need for renal replacement therapy in patients with non-dialytic CKD.This is a retrospective cohort study using prospectively collected data on adult patients (> 18 years) followed in the progressive renal insufficiency clinic at Botucatu Medical School, located in Botucatu, Brazil. The progressive renal insufficiency clinic is a specialty multi-disciplinary care clinic in the CKD program for patients approaching ESRD. Patients with progressive kidney disease are referred to this clinic at the discretion of primary nephrologist in anticipation of needing renal replacement therapy. Causes of CKD were: hypertension (40%), Diabetes , Glomerular  and others . Attempts were made to collect 24-h urine for sodium excretion at least twice per year. Standardized instructions are given to each patient for collection of 24-h urine. The study included patients with non-dialytic CKD, at least two visits to the clinic and at least one 24-h urine sodium excretion (USE) measurement between October 2006 and November 2010. Patients who required any kind of renal replacement therapy prior to the laboratory test, in malignant phase of hypertension, hepatic insufficiency, alcoholics and with malignant neoplasm were excluded.Data on all patients were obtained through the clinic’s comprehensive database since its inception in October 1st, 2006. The accuracy of the data in the database is verified every six months by auditing 5% of entries and accuracy has been > 95%. Data collected included age, gender, blood pressure (BP), body-mass index (BMI), eGFR, urine excretion of sodium, protein and creatinine, cause of CKD, comorbidities, medications, date of death and date of initial dialysis or renal transplantation.Blood pressure was measured in sitting position after at least five minutes of rest. Blood pressure, eGFR and proteinuria were measured at each clinic visit. 24-h USE was performed periodically to monitor compliance and assist in counseling patients regarding sodium restriction. Hypertension was defined as an average BP ≥ 140/90 mmHg or self-reported use of antihypertensive drugs. Diabetes mellitus was defined according to the American Diabetes Associations criteria . The estn = 41):1st quintile: 0.54–2.51 g; 2nd quintile: 2.52–3.11 g, 3rd quintile: 3.12–3.97 g, 4th quintile: 3.98–5.24 g and 5th quintile: 5.26–13.80 g. The 1st quintile: (0.54–2.51 g) was selected as reference. We choose this point of sodium intake to be the recommended for patients CKD [Sodium intake for each patient was estimated from the average 24-h USE measured during the follow-up period. A priori, we categorized the patients according to their mean 24-h USE into five groups . The secondary outcome was mortality from any cause. Surviving or of dialysis-free patients at the end of the follow, as well as those transferred from the service or having lost the segment were censored.p < 0.05.Continuous variables are reported as mean (± SD) and categorical variables are reported as median interquartile range and percentages. Continuous variables were obtained by calculating the average between the results of the first and second exams. Chi squared test was used to compare categorical variables. Student’s “t” test and Mann Whitney test for non-parametric data. Time-to-event analyze was conducted using the Cox proportional hazards. Sodium intake was insert time-dependent Cox models using the quintiles 24-h USE. Those variables associated with outcomes in the preliminary analysis (level of 0.05) were used model Cox. Potential confounders included in the Cox models were age, smokers, eGFR, urinary protein/creatinine excretion. The variable PTH, serum phosphor, serum creatinine weren´t used in the Cox model because of collinearity with eGFR. Outcome mortality: age, eGFR, DBP, Diabetes e CVD were included in model Cox. For all tests, statistical significance was defined as Two Hundred Ninety-two patients were screened and 88 were excluded by lack or incomplete 24-h urine samples. The mean follow-up was 2.6 years. The baseline characteristics were presented in Tables n = 41) with the respective intervals: 1st quintile: 0.54–2.51 g; 2nd quintile: 2.52–3.11 g, 3rd quintile: 3.12–3.97 g, 4th quintile: 3.98–5.24 g and 5th quintile: 5.26–13.80 g. The average sodium daily intake of the participants was 3.9 g, which represents about 9.75 g of sodium chloride.Based on the mean USE during the observational period, 205 patients were categorized into quintiles (Thirty Seven patients 18%) reached the primary outcome.These patients had higher values of: serum creatinine, proteinuria, serum phosphor, urinary protein/creatinine excretion, parathyroid hormone and smokers. Age and eGFR were lower in patients who reached the primary outcome  was significantly associated with lower risk of progression to ESRD ;  died. The causes of mortality were: 23 44%) infectious disease, 18 (35%) CVD, five (10%) malignancies and six (12%) deaths to others causes. Variables that showed statistical differences in relation to the secondary outcome were: age, previous CVD, eGFR and urinary creatinine excretion ; Table .Table 6TThis study showed that urinary sodium excretion (as a surrogate for sodium intake) between 2.52–3.11 g/day was associated with a lower risk ESRD when compared with the reference 0.54 – 2.51 g/day. No other urinary sodium excretion quintile was associated with the primary outcome. Likewise, was not significant association with mortality.Studies that evaluated the association between sodium intake and renal outcome obtained some different results , 24. In He et al. showed that urinary sodium excretion above 4.47 g was associated with 54% increase risk of CKD progression . The cohIn the studies cited above, higher sodium intakes were associated with CKD progression in models without the variable proteinuria. In the current study, the association between the second quintile of sodium and renal failure was obtained after adjustment for proteinuria. This association was independent of protein intake and BP.In humans, a moderate restriction in sodium intake potentiates the antiproteinuric and antihypertensive effects of renin angiotensin system blockers . HoweverAn interesting finding of this study was that smokers evidenced greater risk to ESRD. This result corroborates to previous research , 33. ExpIn relation to the mortality outcome, Mills et al.  reportedOur study should be interpreted taking into account its limitations. First, this is an observational study which does not allow definitive conclusions on the causality of the association between sodium intake and outcomes. Only two 24-h urine samples may not be enough to estimate the usual sodium intake with precision, but most studies have performed only a single dosage. As points positive: was added the proteinuria in the model Cox because is an important factor in CKD progression. In addition, we performed a measurement of sodium intake by the method of 24-h USE, which is considered the gold standard . FinallyIn conclusion, in this longitudinal study, moderate sodium intake was associated with a lower risk of progression to renal failure in patients with established CKD. Further studies are needed confirm the association between sodium intake and outcomes in non-dialysis CKD patients.


Slow breathing at 0.1 Hz  leads to strong cardiovascular oscillations. However, the impact of breathing below 6 cpm is rarely addressed. We investigated the influence of OM chanting, an ancient Indian mantra, with approx. 3 respiratory cpm (0.05 Hz) on the synchronisation of heart period (RR), respiration (RESP) and systolic blood pressure (SBP). Nine healthy, trained speech practitioners chanted three sequences of five subsequent OM with 2 min pauses in between. Each single OM chanting consisted of taking a deep breath and a long “OM” during expiration and lasted approx. 20 s. ECG, respiration and blood pressure were recorded continuously, of which the RR tachogram, RESP and SBP were derived. Synchronisation between the signals was computed using the phase difference between two signals. During OM chanting synchronisation among the oscillations of RR, SBP and RESP was significantly increased compared to rest. Furthermore, OM chanting at breathing frequencies between 0.046 and 0.057 Hz resulted in 0.1 Hz oscillations in RR and SBP. In conclusion, OM chanting strongly synchronized cardiorespiratory and blood pressure oscillations. Unexpected oscillations at 0.1 Hz in SBP and RR appear at breathing frequencies of approx. 0.05 Hz. Such frequency doubling may originate from an interaction of breathing frequency with endogenous Mayer waves. Influences of different breathing frequencies and patterns on cardiovascular regulation have been investigated in the past decades . It has During meditative chanting of OM, a state of mental alertness is induced , which iFunctional magnetic resonance imaging in healthy individuals showed reduced outputs from the insula, anterior cingulate and orbitofrontal cortices during OM chanting . Of possIt has been shown that oscillations of different physiological systems such as heart period and respiration may interact and intermittently synchronise  and it iOM chanting induces slow breathing at approximately 3 cycles per minute. This breathing rate is considerably slower than breathing at 6 cycles per minute which is often associated to “slow breathing”. It leads to a strong coordination and interaction of cardiovascular oscillations with respiration, involving central and peripheral neural networks , thus suThese effects are not limited to the intervention itself. The increase in cardiorespiratory coordination persists after slow breathing for 15–20 min and similarly after recitation of ancient verse . Such reIn a preliminary study performed by our research group, we observed that two heart period oscillations appeared during one OM breathing cycle . InteresAfter providing written informed consent, subjects were enrolled in the study. All subjects were healthy and professional speech and drama therapy practitioners. The practitioners had a personal interest in understanding the physiological mode of action underlying ATS and keen to aid in this research. The study protocol was approved by the Ethics Committee of the Canton Zurich (KEK-ZH-Nr. E-50/2002).2. All subjects were familiar with OM chanting.From originally ten subjects, one had to be excluded due to frequent ectopic heartbeats. The remaining nine subjects were included and had no history of cardiovascular diseases, especially no hypo- or hypertension. The nine subjects consisted of five female and four male volunteers, age 41 ± 7.6 years, BMI 22.8 ± 3.2 kg/mEach subject took part in one experimental session of 30 min. The session consisted of a pre-resting period of 10 min (baseline), three sequences of five subsequent OM chantings with a 2 min pause between the sequences and a post-resting period of 10 min (recovery). All phases of the experiment were performed in standing position. During pauses between the OM chanting and during the resting periods the subjects breathed spontaneously. OM chanting was instructed to be full-toned at normal pitch and on one breath and the duration of each OM to be approximately of the same length within an individual subject. No pacing was introduced to allow for a natural interindividual variance in chanting pace.During each session, the ECG (lead II) with automatic R-peak detection  and the nasal/oral airflow (sampling rate 64 Hz) were recorded by a Holter device . The uncalibrated continuous blood pressure using a finger-cuff measurement device  was simultaneously continuously recorded during the entire session.The automatically detected R peaks were visually examined using both the ECG and the RR tachogram and manually corrected for ectopic beats. The beat-to-beat systolic blood pressure and a blood pressure based interbeat interval series (corresponding to the RR tachogram) were derived from the continuous blood pressure signal using dedicated software. The blood pressure derived interbeat interval series was visually inspected and manually corrected for outliers as well. Subsequently, ECG and respiration were time matched with the continuous blood pressure signal by matching their RR tachograms, after both had been resampled to 10 Hz. Respiratory cycles were derived from the nasal/oral airflow using successive local minima.SBP (n-1) was paired with xRR (n), with xSBP (n) and xRR (n) being the nth sample of the systolic blood pressure beat-to-beat series and RR tachogram, respectively. Furthermore, the minimal number of elements in each BRS sequence amounted to 3, the minimal absolute difference in SBP between two consecutive samples was 1 mmHg and the minimal absolute difference in RR equalled 5 ms between two consecutive samples. Moreover, the minimal coherence in each sequence had to be at least 0.8. It was verified that a sufficient number of data elements were available for computing the BRS (between 15–121 for OM and the resting periods), so that the abovementioned method led to reliable statistical results (OM), pre-resting (BRSPRE) and post-resting (BRSPOST).BRS was computed according to the sequence method , hence x results . One medSynchronisation between respiration, RR tachogram and beat-to-beat systolic blood pressure was analysed using the oscillations in heart period as well as in systolic blood pressure induced by respiration . To determine synchronisation between two signals, the cross-correlation function may be used. However, a parameter of synchronization γ has been proposed to better discriminate synchronisation during varying activity levels . This pa0,RR, and applying a band-pass filter with centre frequency fc = f0, RR and bandwidth bw = /3 to both RR and RESP. Next, for each of the 3 OM sequences synchronisation between the filtered RR and RESP signals is determined and its average value equals γ1. For the second harmonic of RR, the same procedure is repeated, except that fc = 2f0, RR. This results in synchronisation γ2. The average of γ1 and γ2 is γRR. Subsequently, the same procedure as for RR is applied to RESP as a reference, resulting in synchronisation γRESP. Synchronisation γOM between RR and RESP is taken as the maximum value of γRR and γRESP.A flow diagram for computing synchronisation between RR and RESP during OM is depicted in OM, with 50% overlap to RR and RESP, where TOM is the sum of the time lengths of the 3 OM sequences. To each pair of corresponding RR and RESP data window, the same procedure as during OM was applied for computing synchronisation, with two exceptions. First, we created 3 separate sequences by splitting the data in the sliding window in 3 non-overlapping windows of equal length, to proceed identically as with the 3 OM sequences. Secondly, because RR and RESP hardly showed harmonics during the resting periods, we took for the first spectral peak the largest in the frequency range between 0.0375 and 0.2 Hz . This resulted in synchronisations γPRE and γPOST.For computing synchronisation between RR and RESP during pre- and post-resting periods, we applied a sliding window of length TOM was obtained and a set of values for γPRE and γPOST .Using the method described above, one value per subject for γOM , between 9 and 18 values for γPRE  and between 9 and 18 values for γPOST.The combination RR and SBP and the combination RESP and SBP were analysed analogously. We therefore obtained for each subject: 3 values for γAll statistical analysis was performed using non-parametric statistical procedures. Hence, median values and the interquartile range (IQR) were used to quantify the distributions. Differences in the RR interval, the respiratory cycle (RESP), BRS and synchronisation γ during pre-resting, OM and post-resting periods were analysed by the Friedman test. In case of significant difference, the Wilcoxon signed rank test was used to examine which of the three pairs  were significantly different, using the Bonferroni correction for multiple testing.OM-PRE = SBPOM—SBPPRE, ΔSBPOM-POST = SBPOM—SBPPOST and ΔSBPPRE-POST = SBPPRE—SBPPOST, where SBPPRE, SBPOM and SBPPOST are the median systolic blood pressure during pre-resting OM and post-resting periods, respectively. To correct for multiple testing the Bonferroni correction was applied. A p-value < 0.05 was considered statistically significant for all tests.Since uncalibrated SBP values were recorded, i.e., each blood pressure measurement (subject) had a different offset, we performed a Wilcoxon signed rank test to SBP differences: we calculated for each subject ΔSBPThe top panel of Both for the respiratory cycle and the RR interval, the Friedman test showed considerable variation across pre-resting, OM and post-resting . In the left panel of OM—SBPPRE. The differences in SBP between OM and post-resting, and between pre-resting and post-resting are defined analogously. In the left panel of Since SBP was not calibrated, we investigated differences in SBP. The difference in SBP between OM and pre-resting for a particular subject is ΔSBP = SBPBRS showed significant variation across pre-resting, OM and post-resting (p < 0.01). BRS during pre-resting was significantly higher than during OM. Between OM and post-resting and between pre- and post-resting, no significant differences were found , RR-SBP (p < 0.01) and RESP-SBP (p < 0.001). Synchronisation in all subjects during OM chanting and both resting periods is shown in RESP-SBP = 0.26π (0.18π to 0.46 π) and ɸRESP-RR = 0.52π (0.38π to 0.59 π), which corresponded with a delay of 2.33 (1.47–3.27) seconds for SBP and of 3.84 (3.33–4.80) seconds for RR intervals.The time order of the signals was always RESP—SBP—RR. The median (IQR) phase differences amounted to ɸ0,RR, and the first harmonic of the SBP, f0,SBP, respectively . A second oscillation with an amplitude almost as high as in the preceding oscillation (relative amplitude >0.7) appeared in the RR tachogram of three subjects. These oscillations occurred at frequencies of the first harmonics in the range 0.046–0.057 Hz. There were also three subjects that hardly showed a second oscillation in the RR tachogram. They showed relative amplitudes <0.1 and had frequencies of the first harmonic between 0.057 and 0.092 Hz. Furthermore, three subjects showed intermediate levels of the amplitude of the second oscillation (frequency range 0.05–0.073 Hz). For the SBP time series the amplitude of the second oscillation was in the intermediate range  for all subjects except one (at 0.094 Hz).During one OM chant, a clearly visible non-respiratory second oscillation appeared in the time signals of SBP and RR intervals  has been investigated sparsely. To the best of our knowledge only one study investigated respiratory frequencies in the range of 0.01–0.143 Hz with respect to its impact on heart period and SBP . In thisDuring OM chanting the median delay of SBP and RR interval series with respect to respiration was 0.52π and 0.26π. These results differ slightly from Vaschillo’s findings . However2 sensitive central and peripheral chemoreceptors and thus contributing to the observed reduction in BRS. This effect may be enhanced by the conscious control of breathing in our experiment  leads to a “baroreflex resonance” called Traube-Hering waves . I.e. a Besides the Traube Hering waves, the so-called Mayer waves occur in the form of blood pressure oscillations at 0.1 Hz independent of respiration . FunctioIn the present study, Traube Hering waves are unlikely to generate the observed second non-respiratory related oscillation. The inspiration during OM chanting could have initiated Traube Hering waves. However, respiration and oscillations in heart period during OM chanting are not out of phase by π as they should be in the case of Traube Hering waves . InsteadHowever, the present data cannot answer this question unambiguously. Previous results indicate that the cardiovascular response on respiration at 0.05 Hz is different to respiration at 0.1 Hz . Hence, The non-respiratory oscillations at 0.1 Hz in SBP and RR interval in our experiment occur predominantly at a breathing frequency half of the Mayer waves (1:2 ratio). At slightly higher respiration frequencies (close to but still below 0.1 Hz) the second non-respiratory oscillation attenuates. Hence, the second non-respiratory oscillation does not originate from entrainment with e.g. blood pressure oscillations. Such an entrainment would lead to enhanced oscillations instead of diminished oscillations. Instead, it seems that the second oscillation only appears if there is enough time for a complete oscillation. It has been suggested that the human organism tends to establish a coordinated time structure of physiological functions such as heart period and respiration . This tiPRE and γPOST in RR-SBP as compared to RR-RESP and RESP-SBP  frequencies at approximately 0.05 Hz, two oscillations appear in heart period and systolic blood pressure during one breathing cycle: the first oscillation is induced during inspiration in the beginning of OM whereas the second oscillation is not induced by respiration. If the breathing frequency exceeds 0.065 Hz, the second oscillation in blood pressure and heart period disappears. Further systematic studies at respiratory frequencies below 0.1 Hz incorporating different inspiration to expiration ratios are needed to shed more light into the physiological control of heart period and blood pressure during consciously mediated breathing modalities.Interestingly, most subjects choose a breathing frequency of approximately 0.05 Hz. Trained speech therapists seem to prefer a respiration frequency for OM chanting with an integer ratio (1:2) to a deeply engrained physiological rhythm, the Mayer waves . In the time order, respiration always leads and is followed by the oscillations of systolic blood pressure and heart rate variability. This research shows that OM chanting has profound effects not only on respiration, but also on heart period and blood pressure. These may be applied therapeutically.


To evaluate the acute effects of caffeine and glucose intake on retinal vascular calibre of healthy adults.This prospective crossover study was conducted at the Centre for Eye Research Australia . Standardized doses of 300 mg caffeine (approximately 3 cups coffee), 30 g glucose or 300 ml of water, were each given to 19 healthy subjects on separate days. Retinal photographs and blood pressure measurements were taken at baseline, 30-, 60- and 120-min after ingestion of each solution. Central retinal artery and vein equivalents  and the arterio-venule ratio were measured using computer-assisted software. The mean retinal vascular calibre measurements were compared between pre- and post-ingestion images.p ≤ 0.002 for all; paired t test). No significant changes were observed in mean retinal vascular calibre measurements after intake of either glucose or water when compared to baseline . When controlling for baseline characteristics and blood pressure measurements, only caffeine intake had a significant effect on reducing both CRAE and CRVE at all time points post ingestion .After caffeine intake, significant reductions were observed in mean CRAE of − 9.3 μm, − 10.4 μm and − 8.5 μm and CRVE of − 16.9 μm, − 18.7 μm and − 16.1 μm at 30-, 60- and 120-min after intake when compared with baseline (Caffeine is associated with an acute vasoconstrictive effect on retinal arterioles and venules in healthy subjects. Factors other than blood pressure-induced autoregulation play a significant role in caffeine-associated retinal vasoconstriction.The online version contains supplementary material available at 10.1007/s10792-022-02417-z. The advent of modern digital image systems provides us the unique opportunity to reliably and objectively assess the retinal microvasculature in large population cohorts. As retinal vessels are easily imaged non-invasively in vivo, significant efforts have been made to investigate whether retinal vascular calibre measurements may reflect the state of the body’s microcirculation and, therefore, be a biomarker for cardiovascular and cerebrovascular disease. Various epidemiologic and clinical-based studies have since demonstrated that retinal vascular calibres are associated with systemic disease including hypertension , diabeteCaffeine and glucose, two widely consumed constituents, have both been purported to alter ocular vessel haemodynamics. Caffeine, a natural purine alkaloid and adenosine receptor antagonist, has been shown to decrease blood flow in retrobulbar blood vessels  and to tThis prospective crossover study was performed at the Centre for Eye Research Australia and was conducted in accordance with the Declaration of Helsinki of 1975. Ethics approval for this study was obtained from the Human Research Ethics Committee of the Royal Victorian Eye and Ear Hospital.Nineteen healthy medical students and staff at the Centre for Eye Research Australia were recruited to participate in this study. Inclusion criteria for all participants were to be aged 18 years old or older with no history of systemic disease or current medication use. Potential subjects were excluded if they had diabetes, hypertension, stroke, kidney or heart disease, any known ocular diseases  or any media opacity. Refractive error was permitted as long as this was within ± 2 diopters of emmetropia.Three test solutions were each given in turn to the subjects, using a pattern of multiple crossover design, on separate visits over a period of up to two weeks. The order of administration of each test solution was randomly assigned. At each visit, the participant received one test solution containing a standardized dose of either (a) 300 mg caffeine dissolved in 300 ml of water, (b) 30 g sugar dissolved in 300 ml of water or (c) 300 ml of water. The caffeine dose was chosen to mirror the average intake of caffeine per day for a 70-kg adult, which in most Western countries is estimated to be 200 to 300 mg per day .. At each visit, after pupil dilation with tropicamide 0.5%, retinal photography from both eyes, was obtained at baseline before the administration of any substance, and then at 30-, 60- and 120-min post ingestion. The time interval for measurements is based on the peak plasma concentrations of caffeine occurring between 30 and 120 min after oral administration [To minimize diurnal variation effects, testing was performed in the morning at each visit for each participant. All participants were instructed to fast from midnight and avoid caffeinate drinks for 12 h prior to each study visitstration .Digital retinal photography was used to assess retinal vessel calibre and was performed according to a standardized protocol with a 45º digital nonmydriatic Canon CR6-45NM camera  with photographic fields taken of each eye centred on the optic disc. Right eye retinal photographs were selected for measurements. If the right eye fundus photograph was of insufficient quality for retinal vascular calibre measurement for any participant, the left eye was used.Retinal vascular calibre was measured using standardized computer-assisted semi-automated imaging software Integrative Vessel Analysis  . For eac.Systemic blood pressure (BP) was measured at each visit using an automated device with an appropriately sized cuff with the subjects in a seated position. A single measurement was taken after at least a 5-min period of rest at each time point. In the first nine recruited subjects, BP was only measured at baseline. However, to study the correlation between the results and the change in the BP, the subsequent ten subjects had BP measured at baseline, 30-, 60- and 120-min. Mean arterial pressure (MAP) was calculated by the formula utilizing systolic blood pressure (SBP) and diastolic blood pressure (DBP): MAP = DBP + 1⁄3 (SBP–DBP)p < 0.05. The impact of each independent variable  on CRAE and CRVE at 30-, 60- and 120- minutes was analysed with a multivariate regression model. All statistical analyses were conducted using SPSS software .Retinal vascular calibre measurements  and blood pressure measurements  were assessed as continuous variables. Normality was assessed for all analyses, and appropriate non-parametric methods were applied as necessary. Comparisons of vessel calibre measurements and blood pressure measurements between baseline and post-ingestion measurements at 30-, 60- and 120-min were performed by a paired sample t-test to account for the within-eye pairing of measurements. The relationships between the retinal vascular calibres  and the blood pressure measurements  were calculated with the Pearson correlation coefficient. Significance levels were set at . The habitual caffeine intake of participants ranged from 0 and 4 cups of coffee per day : 1, 1.5 ± 0.9 cups per day. A standard 8 oz cup of coffee will have approximately 100 mg of caffeine [Nineteen subjects  were recruited in this study. The mean age of the participants was 29.5 ± 8.2 years (range 22–53) with an average BMI of 22.8 ± 2.6 (range 19.2–29.0)caffeine .p ≤ 0.002 for all; paired t test). Significant increases were observed in mean AVR at 30- and 60-min after caffeine intake when compared to baseline (p ≤ 0.002 for both). The increase in AVR at 120-min after caffeine intake, when compared to baseline, approached statistical significance (p = 0.065). No significant changes were observed in mean CRAE, CRVE and AVR at 30-, 60- and 120-min after intake of either glucose or water alone when compared to baseline .Mean retinal vascular calibre measurements prior to, and at 30-, 60- and 120-min following, intake of 300 mg of caffeine, 30 g of glucose and 300 ml of water, are demonstrated in Table p > 0.21). The results of the mean blood pressure measurements prior to, and at 30-, 60- and 120-min following, intake of caffeine, glucose and water alone are available in Online Resource 1. Significant elevations however were observed in mean SBP at 30-, 60- and 120-min after caffeine intake when compared with baseline , while DBP and MAP values did not change following caffeine ingestion throughout the study . Significant reductions were observed in mean DBP and MAP at 120-min after glucose intake when compared to baseline (p ≤ 0.017 for both). Otherwise, no other significant changes in SBP, DBP or MAP were observed at all time points after intake of either glucose or water alone when compared to baseline . No significant correlations were found between blood pressure markers  and retinal vascular calibre measurements at the baseline, 30-, 60-, and 120-min after the intake of caffeine; CRAE , CRVE  and AVR .Overall, there were no significant changes in mean SBP, DBP or MAP from baseline to 30-, 60- and 120- minutes , p = 0.002 at 60 min and by − 14.28 μm , p = 0.001 at 120 min. Likewise, after controlling for other characteristics, CRVE reduced by − 13.71 μm , p = 0.002, 30 min after caffeine ingestion. At 60 min and 120 min, a reduction of − 11.89 μm , p = 0.001 and − 16.88 μm , p = 0.001 respectively, were observed.The results of the multivariate regression model looking at characteristics for subjects  and their influence on CRAE and CRVE at 30-, 60- and 120- minutes are available in Online Resource 2. After controlling for other characteristics, there was a significant effect of caffeine intake, − 13.12 μm , p = 0.04, at 120 min post intake, but not at 30- or 60- minutes post ingestion. Similarly, mean SBP at baseline reduced CRVE by − 0.46 μm , p = 0.03 at 120 min, but not at 30- or 60- minutes post intake.After controlling for other characteristics, there was a significant effect of gender on CRVE of − 19.03 μm , In the current study, we observed a significant narrowing of retinal arterioles and venules in healthy subjects for at least 2 h after 300-mg of oral caffeine intake. No significant change in retinal vascular calibre was seen following ingestion of glucose or water alone. An increase in systolic blood pressure was observed following caffeine intake, however after controlling for blood pressure measurements and baseline characteristics, only caffeine intake had a significant effect on reducing both central retinal artery and vein equivalents at all time points up to 120 min post ingestion.Our study adds to the growing evidence observing the significant effect of caffeine intake on ocular blood flow and vascular resistance. Macular blood flow and ocular blood velocity have been shown to significantly reduce after oral caffeine ingestion , 10. CafTo our knowledge, Terai and colleagues have published the only previous study to investigate the acute effect of caffeine on retinal vascular calibres . They obOur findings of a mean change in CRAE and CRVE of 10.4 μm and 18.7 μm respectively, 60-min after caffeine ingestion, is comparable to the magnitude of retinal vascular calibre changes reported to be associated with a significant increased risk of cardiovascular events. As an example, a meta-analysis by McGeechan et al.  found thThe mechanisms by which caffeine induces vasoconstriction are not entirely clear. Autoregulatory myogenic smooth muscle contraction in response to elevated BP has been suggested to play a key role . HoweverIn our present study, no significant change in retinal vascular calibre was observed within 2-h following ingestion of 30 g of glucose. Various animal and human studies have shown acute increases in plasma glucose is associated with an increase in ocular blood flow –13. HoweGiven the ubiquitous nature of caffeine consumption , knowledOur study has several strengths. Firstly, our crossover study design assisted to exclude non-drug related effects on our measured outcomes. Secondly, our use of standardized computer-assisted semi-automated imaging software to measure retinal vascular calibres ensured our measured parameters were a robust cross-sectional representation of retinal vessel calibre. The current study however is limited by small participant numbers. The results of our regression analyses, particularly the statistically significant effect of gender and mean SBP at baseline, on the change in CRVE at 120-min post ingestion of caffeine, may have been influenced by the small sample size. Finally, our participants may be younger than most participants enrolled in clinical studies evaluating the association between cardiovascular events and retinal vascular calibre measurements. It is possible the vasoconstrictive response associated with caffeine found in our cohort may not represent those seen in cohorts of older participants.In conclusion, our study has demonstrated the acute vasoconstriction associated with caffeine on retinal arterioles and venules in healthy subjects. Our results indicate that future epidemiologic and clinical-based research on retinal vessel calibres should take into account the possibility of caffeine-associated changes in retinal vessel measurements.Supplementary file1 (PDF 76 KB)Supplementary file2 (PDF 65 KB)Below is the link to the electronic supplementary material.