The incidence of left ventricular (LV) thrombus formation in ST-segment elevation myocardial infarction (STEMI) patients in the current era of primary percutaneous coronary intervention (PCI) is not well established. We performed a meta-analysis to assess the actual incidence and predictors of LV thrombus by cardiovascular magnetic resonance (CMR) in STEMI treated by primary PCI.We searched MEDLINE and EMBASE databases up to February 2018. We included all studies published as a full-text article, reporting the incidence of LV thrombus by CMR within 1 month following acute STEMI in patients treated by primary PCI. A binary random-effects model was used to estimate the pooled incidence of LV thrombus. The diagnostic performance of transthoracic echocardiography (TTE) as compared with CMR was pooled to obtain the sensitivity and specificity of TTE with CMR as the gold standard. Embolic and bleeding complications of LV thrombus were also evaluated.n = 2072) was 6.3% with 96% of LV thrombus occurring in those with anterior STEMI (12.2% incidence). When only anterior STEMI with LVEF< 50% were considered (n = 447), the incidence of LV thrombus was 19.2%. Compared with CMR, the sensitivity of TTE to detect LV thrombus was 29% with a specificity of 98%. The sensitivity of TTE increased to 70% in those with anterior STEMI and reduced LVEF. LV thrombus resolved in 88% of cases by 3 to 6 months. After 1–2 years follow-up, the embolic complication rate was similar at 1.5% (P = 0.25) but the bleeding complication rate was significantly higher  in the LV thrombus group on triple therapy when compared to the no LV thrombus group on dual antiplatelet therapy.Ten studies were included in the meta-analysis. The incidence of LV thrombus by CMR in all-comer STEMI patients (In the primary PCI era, CMR detection of an LV thrombus post-STEMI remains high with incidence of nearly 20% in anterior STEMI with depressed LVEF. Patients with LV thrombus treated by triple therapy had similar embolic complications but higher bleeding complications than those with no LV thrombus treated with dual antiplatelet therapy. A 3 month follow-up CMR scan to guide anticoagulation duration might help mitigate bleeding risk. Primary percutaneous coronary intervention (PCI) is the reperfusion strategy of choice for the treatment of ST-segment elevation myocardial infarction (STEMI). Although left ventricular (LV) thrombus formation is a recognized complication in STEMI patients, its incidence in the era of primary PCI is not well established. LV thrombus may lead to embolic complications such as stroke, with devastating consequences. Both the American College of Cardiology/American Heart Association/and European Society of Cardiology guidelines , 2 recomA meta-analysis recently reported that the ovrall rate of LV thrombus by transthoracic echocardiography (TTE) in the primary PCI for STEMI era was 2.7% with 9.1% for anterior STEMI . HoweverWe therefore performed a meta-analysis to assess the incidence and predictors of LV thrombus by CMR in STEMI patients treated by primary PCI in the current era and to evaluate how it may be used in the clinical setting, in conjunction with TTE, to improve LV thrombus detection.This meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement  and was All studies reporting on the incidence of LV thrombus by CMR in STEMI patients treated by primary PCI were eligible for inclusion. The inclusion criteria were all studies published as a full-text article reporting the CMR incidence of LV thrombus within 1 month following acute STEMI in patients treated by primary PCI. Conference abstracts were excluded.We searched Ovid MEDLINE and Ovid EMBASE databases up to February 2018. Furthermore, we screened editorials and references of eligible studies. The following search terms were used: “ventricular”, “apical”, “thrombus”, “magnetic resonance imaging”, “acute myocardial infarction”, “primary percutaneous intervention”.Two authors  identified suitable articles independently. Disagreement was resolved through consensus from a third investigator (DJH). Figure Baseline clinical characteristics of the study population were extracted. Trial quality was determined as per the Cochrane Handbook  but withThe main endpoints analyzed were incidence of LV thrombus identified on the acute CMR and follow-up CMR when available. Furthermore, the incidences of embolic and bleeding complications as defined by the individual studies were also collected.2 statistics with I2 of 0–25%, 25–50% and 50–75% considered as low, moderate and high heterogeneity, respectively.The studies were divided into those including all-comer STEMI, anterior STEMI patients and those with anterior STEMI and with reduced LV ejection fraction (LVEF). A binary random-effects model was used to estimate the pooled incidence of LV thrombus with 95% confidence interval (CI) using OpenMeta[Analyst]  softwareTen studies , 9–17 wen = 2072) was 6.3% (95%CI 4.2–8.5), I2 of 72%  [2 = 64%,  and was 12.8% (95%CI 10.6–15.0%) for anterior STEMI (n = 886), with I2 of 9% and 0%, respectively.Sensitivity analysis was performed by excluding the studies by Poss 2015  and Lanz2 = 90%.Three studies –17 incluThree studies (acute CMR performed within the first week) also had a repeat CMR between 3 to 6 months –14. LV tThree studies , 11, 12 For anterior STEMI with reduced LVEF, 3 studies also presented data on the detection of LV thrombus by both TTE and CMR. For the 246 patients, the sensitivity of TTE for LV thrombus was 70% (95%CI 56–82%) with a specificity of 98% (95%CI 94–99%).Three studies , 13, 17 P = 0.25, I2 = 0%. However, bleeding complications were significantly higher in the LV thrombus group  than in the no LV thrombus group , P < 0.001, I2 = 65%.After a follow-up period of between 1 and 2 years, the incidence of embolic complications  was similar at 1.5% in both the LV thrombus group (1/68) on triple therapy  and no LV thrombus group (9/616) on dual antiplatelet therapy only, In this meta-analysis of more than 2000 patients, overall CMR evidence of LV thrombus was > 6% of primary PCI STEMI patients. This is more than twice that reported by TTE . We alsoExpectedly, the large majority (96%) of LV thrombus by CMR occurred in those with anterior STEMI. The incidence of LV thrombus in anterior STEMI was more than 12%. In the subgroup of patients with anterior STEMI and LVEF< 50%, LV thrombus by CMR was detected in a remarkably high proportion of patients: one in five patients. Of note, the sensitivity of TTE was higher at 70% in this subgroup of patients.n = 738). This may be related to the early use of the potent glycoprotein IIb/IIIa inhibitor abciximab (intracoronary or intravenous) and warrants further investigation.The incidence of LV thrombus in the study Poss 2015  was loweThe incidence of LV thrombus by CMR is dependent on the timing of the CMR scan. An additional 3% of patients were identified to have late LV thrombus of the CMR performed between 3 and 6 months. Gellen et al.  recentlyConsistent with prior studies, risk factors for LV thrombus formation were anterior STEMI and LVEF< 50% , 13. TheAlthough the number of studies was limited, accounting for 684 patients, the incidence of embolic complications in those with LV thrombus and treated by anticoagulation was similar to those without LV thrombus. However, as expected, those with LV thrombus and triple therapy had higher incidence of bleeding complications. The large proportion of LV thrombus (88%) resolved on the repeat CMR performed between 3 to 6 months. A follow-up CMR scan as early as 3 months after STEMI may reduce the need for prolonged anticoagulation in a proportion of patients.LV thrombus post acute STEMI is well recognised to occur predominantly at the apex  and in tLV thrombus can sometimes be difficult to distinguish from MVO. The following previously described criteria  can be aContrast TTE has also been used for the detection of LV thrombus with an improved sensitivity of 64% when compared to CMR [In the chronic MI setting, in a cohort of patients with ischemic heart disease undergoing assessment for LV reconstruction surgery, the sensitivity of CMR against the pathological confirmation of LV thrombus was high at 88% . The sen2 significantly. Several of the secondary analyses included data from only 3 studies, but these constituted the largest pooled analyses and need to be confirmed in future larger prospective studies. Patient-level data were not available. Despite these limitations, our study provides a more accurate estimate of the true incidence of LV thrombus from a pooled analysis of > 2000 STEMI patients in the current primary PCI era. However, a proportion of STEMI patients with LV thrombus currently go undetected, as CMR is not part of routine practice. The natural history of these patients, especially in the current era of potent antiplatelet therapy is not known and could not be answered by this study. Lastly, CMR is currently not widely available, is relatively expensive and there may be an element of selection bias .The techniques used in this meta-analysis to detect LV thrombus by TTE did not include echo contrast or newer 3D volumetric methods. The techniques used to detect LV thrombus by CMR  and in patients with inconclusive TTE. Patients with LV thrombus treated with triple therapy  have similar embolic complication rates but higher bleeding complication rates as compared with those with no LV thrombus treated with dual antiplatelet therapy only. We suggest a repeat CMR scan at 3 months post-STEMI to guide anticoagulation duration and to potentially reduce bleeding risk.


This method is particularly useful when changes are subtle and not easily determined by traditional parameters, as it is in arterial hypertension and atrial fibrillation (AF). The aims of our study were: to determine LA contractile, conduit and reservoir function by 2D strain imaging in patients with mild arterial hypertension and paroxysmal AF; to assess LA contractile, conduit and reservoir functions’ relation with LV diastolic dysfunction (DD) parameters.2, peak tricuspid regurgitation velocity > 2.8 m/s) present. Number of patients with 0 signs – 17, 1 sign – 26, 2 signs – 19. Contractile, conduit and reservoir functions were compared between the groups.LA contractile, conduit and reservoir functions together with echocardiographic signs of LV DD were assessed in 63 patients with arterial hypertension and paroxysmal AF. Patients were grouped according to number of signs showing LV DD . Reservoir strain was higher in patients with 0 signs compared with other groups (p = 0.014 vs 1 sign of LV DD and p < 0.001 vs 2 signs of LV DD).Mean contractile, conduit and reservoir strains in all the patients were − 14.14 (± 5.83) %, 15.98 (± 4.85) % and 31.03 (± 7.64) % respectively. Contractile strain did not differ between the groups. Conduit strain was higher in patients with 0 signs compared with other groups (The patients with paroxysmal AF and primary arterial hypertension have decreased reservoir, conduit and pump LA functions even in the absence of echocardiographic signs of LV DD. With increasing number of parameters showing LV DD, LA conduit and reservoir functions decrease while contractile does not change. LA conduit and reservoir functions decrease earlier than the diagnosis of LV DD can be established according to the guidelines in patients with primary arterial hypertension and AF. Traditionally the greatest attention during a routine echocardiography is paid to the function of the ventricles and assessment of the atria is limited to measuring the dimensions and volumes of the chambers. Though assessing ventricular function is essential, there is robust data that atrial function is also important and can improve our decision making by determining the risk of cardiovascular events in various conditions . HyperteThere are many well established and validated methods to assess left and right ventricular function but the ones for assessing atrial function are lacking. Speckle tracking echocardiography has proven to be useful and applicable not only in the assessment of LV wall motion abnormalities but also in the assessment of LA function. Though the method is more and more studied it is still not widely used in daily clinical practice primarily because there are still some methodological and standardization issues which need to be addressed. The question of normal values is also still valid, though metanalysis by Faraz Pathan et al. was a real step forward in determining normal ranges .One of the most promising areas the method can be used in is hypertension where the LA and LV dysfunctions occuring early in the course of disease can be subtle and not easily determined by traditional echocardiographic parameters . 2D straThe aims of our study were: a) to determine LA contractile, conduit and reservoir function by 2D strain imaging in patients with mild arterial hypertension and paroxysmal atrial fibrillation; b) to assess LA contractile, conduit and reservoir functions’ relation with LV filling pressure parameters recommended by the American Society of Echocardiography and the European Association of Cardiovascular Imaging .We assessed 63 patients aged 18–80 with I or II grade primary arterial hypertension and at least one ECG confirmed episode of paroxysmal AF within last year. Only the patients that were in sinus rhythm at the time of investigation were included in the study. Patients with other known causes of AF such as heart failure, coronary heart disease, prior heart surgery, structural heart disease, reduced LV ejection fraction, thyroid dysfunction (assessed by thyroid-stimulating hormone concentration) or renal failure with glomerular filtration rate < 60 ml/min were excluded from the study. Only the ones with hypertension as a possible causative factor for AF were included in the study.Physical examination, including weight and height was performed. All patients underwent ambulatory blood pressure monitoring, which was carried out according to European Society of Hypertension guidelines . A MeditAll the patients had an ECG and sonography of the heart done. Only the ones with acceptable ultrasound image quality were included in the final analysis. A GE Vivid E9 system was used for ultrasound imaging in our study. Routine sonographic examination of the heart was performed as described in the American and European Society of Echocardiography guidelines and their update –16 with The thicknesses of the interventricular septal and the inferolateral walls as well as LV end-diastolic and end-systolic diameters were obtained from the parasternal short-axis view. LV mass (LVM) was calculated using linear method as recommended in the update Recommendations for cardiac chamber quantification by echocardiography in adults . Cube foLV and LA volumes were determined using the biplane disk summation technique from apical 4-chamber and 2-chamber views. LV end systolic and end diastolic volume was recorded, then LV ejection fraction was calculated using these measurements.Global longitudinal 2D LA strain was analyzed by the speckle tracking technique using GE EchoPAC software. The images were acquired according to the recommendations given by expert consensus statement published in the European Journal of Echocardiography . For ana2, peak tricuspid regurgitation velocity > 2.8 m/s.LV diastolic function and filing pressures were evaluated according to the American Society of Echocardiography and the European Association of Cardiovascular Imaging recommendations published in 2016 . The patThe intra- and interobserver variability of contractile, conduit and reservoir LA strains was assessed in 20 randomly selected patients. Intraobserver variability was performed by the same echocardiographer blinded to previous measurements and interobserver variability was performed by a second experienced echocardiographer also blinded to previous measurements. The intraclass correlation coefficient together with the absolute difference divided by the mean of two measurements and given as a percentage were calculated for both intra- and interobserver variability.P value of < 0.05 was considered significant.For statistical analysis Microsoft Excel and SPSS Statistics 17.0 software was used. The mean values are presented ± standard deviation (SD) or 95% confidence intervals (CI). Shapiro-Wilk test was used to check if the distribution of the data was normal. The means were compared using ANOVA and Fisher’s Least Significant Difference test was used for post hoc analysis. Pearson’s correlation coefficient was used to test for correlation. Sixty-three patients who met inclusion/exclusion criteria, had acceptable ultrasound picture quality and signed informed consent were included in the final analysis. The patients’ demographic, physical examination and blood pressure data is presented in Table p = 0.367. Conduit strain had statistically significant differences between groups. The group without any signs of LV DD had statistically significantly higher conduit strain (p = 0.016 vs 1 sign of LV DD and p = 0.001 vs 2 signs of LV DD). Reservoir strain also followed the same pattern as conduit strain with the group that had no signs of LV DD having statistically significantly higher reservoir strain values compared with other 2 groups (p = 0.014 vs 1 sign of LV DD and p < 0.001 vs 2 signs of LV DD). Reservoir strain difference between groups with 1 and 2 signs of LV DD did not meet the cutoff of significance, p = 0.072. We also checked for correlation of reservoir strain with average E/e’ ratio and found it to be statistically significant (p < 0.001) with correlation coefficient − 0.432. Regression analysis and scatter plot are shown in Fig. Seventeen patients had no ultrasound signs of LV DD, 26 patients had one sign, 19 patients had two signs and only 1 patient had 3 ultrasound signs of LV DD, which allowed us to firmly diagnose LV DD according to the guidelines . The sinThe method of 2D strain imaging for the evaluation of LA function is being extensively studied and its role in risk determination is constantly increasing. Ability to maintain sinus rhythm after cardioversion or pulmonary vein isolation, reverse atrial remodeling after AF ablation, outcomes in patients with coronary artery disease, exercise capacity in heart failure, development of AF in valvular heart disease, even embolic complications in patients with AF – all these can be predicted by LA strain analysis , 18. ThoOne of the main differences in the methodology is the reference point on the ECG. As most of the studies are done using GE software for LV strain analysis, the default setting is using ventricular cycle and zero reference point by default is set at the apex of R wave. Nevertheless, for the evaluation of atrial function using atrial cycle with zero reference point set at the start of P wave generates negative contractile function strain which is more “physiological” than positive value obtained with R wave reference point. There are more studies done with R being the reference point but most of the experts, including European taskforce members, agree that the onset of the P wave should be used to analyze LA strain in sinus rhythm as we did in our study –21.p = 0.33) [Of no less importance is the question which parts of LA wall to include in the strain analyses. Expert consensus document of EACVI and EHRA on the role of multi-modality imaging for the evaluation of patients with AF recommends LA strain imaging to be performed only in the lateral wall . This wa = 0.33) .Our results show that all three LA functions are lower in patients with mild well treated arterial hypertension and paroxysmal AF compared with recently established normal values. These findings suggest that in hypertensive patients changes in the LA myocardium occur very early and support the role of LA strain imaging as an important and a very sensitive marker of hypertensive heart disease . Recent The second part of our analysis aimed to determine how LA strain parameters change with increasing number of parameters showing LV DD. The relation of LA strain parameters with different LV DD grades has been studied before and it seems that strain parameters follow a distinct pattern with the decreasing LV diastolic function. It has been shown that the most sensitive parameters of LV DD are reservoir and conduit strains, which significantly decrease even in mild LV DD and continue to decrease as the diastolic function gets worse. ROC curves show that diminished reservoir and conduit strains are superior even to LAVI in diagnosing early-stage LV DD. Meanwhile, contractile strain follows a different pattern. With mild LV DD LA contractility can even increase, dropping only when the DD is obvious , 25. ThiOur results confirm this strain changing pattern with decreasing LV diastolic function with the addition that the LA strain changes precede traditional signs of LV DD. Our patients were early in the course of developing DD as the majority of them had only 1 or 2 signs of LV DD which did not allow us to make an echocardiographic diagnosis of LV DD according to the guidelines  but theyIf we followed the recently published guidelines on LV DD , only onThe patients with paroxysmal atrial fibrillation and primary arterial hypertension have decreased all 3 – reservoir, conduit and pump – functions assessed by 2D strain imaging even in the absence of echocardiographic signs of increased LV filling pressures. With increasing number of parameters showing high LV filling pressures LA conduit and reservoir functions decrease while contractile does not change or even increase. LA conduit and reservoir functions decrease earlier than the diagnosis of LV DD can be established according to the current guidelines in patients with primary arterial hypertension and AF.


SMT) provides a novel model to relate multi‐b‐value diffusion magnetic resonance imaging (MRI) data to features of tissue microstructure. We propose the first clinical application of SMT to image the brain of patients with multiple sclerosis (MS) and investigate clinical feasibility and translation.The diffusion‐based spherical mean technique  underwent a 3.0 Tesla scan inclusive of clinical sequences and SMT images (isotropic resolution of 2 mm). Axial diffusivity (AD), apparent axonal volume fraction (Vax), and effective neural diffusivity (Dax) parametric maps were fitted. Differences in AD, Vax, and Dax between anatomically matched regions reflecting different tissues types were estimated using generalized linear mixed models for binary outcomes.Eighteen SMT‐derived parameters between chronic black holes (cBHs) and T2‐lesions (P ≤ 0.0016), in Vax and AD between T2‐lesions and normal appearing white matter (NAWM) (P < 0.0001), but not between the NAWM and normal WM in HCs. Inverse correlations were seen between Vax and AD in cBHs ; in T2‐lesions Dax values were associated with Vax  and AD .Differences were seen in all SMT‐derived metrics are sensitive to pathological changes and hold potential for clinical application in MS patients. Axonal injury is a key element in the pathology of multiple sclerosis (MS) and a major determinant of patients’ disability.Combined MRI‐histopathologic studies provided the demonstration that lesions appearing as hypo‐intense on T1‐weighted spin echo (T1‐w SE) MRI in the absence of corresponding enhancement on postcontrast sequences, namely, chronic black holes (cBHs), represent areas of more advanced disease pathology and axonal loss compared with lesions that show only hyper‐intense signal on T2‐w MRIs.Diffusion‐based imaging offers an opportunity to overcome the limitations of these two techniques.A major limitation of DTI is that its associated signals arise from all water compartments within a voxel.b‐value diffusion MRI data to features of tissue microstructure, recently developed by Kaden and collaborators.b‐values) and much simpler acquisition requirements compared with DBSI.The Spherical Mean Technique (SMT) provides an alternative model to relate multi‐Vax). In the extra‐axonal compartment, SMT models (1) the parallel diffusivity and (2) perpendicular diffusivity, which depends on the packing density of the (myelinated) axons; and the (3) volume fraction 1 − Vax. Relevant to the studies we propose, SMT estimates, the apparent axonal volume fraction (Vax) and the effective neural diffusivity (Dax). Vax is a proxy of the (%) signal fraction arising from axons inside a given voxel, hence relating to the apparent volume fraction of occupied by axons within a given voxel. Dax averages the parallel diffusivity over the intra‐ and extra‐axonal water pools and provides indirect estimates of microenvironments inside the axons and their surroundings.The SMT model has two compartments, that is, the intra‐axonal and extra‐axonal space. In the intra‐axonal compartment, SMT models (1) the parallel diffusivity and (2) perpendicular diffusivity, which is set to zero because of the very small diameter of the axons; and the (3) apparent volume fraction  was mirrored by a reduction of the MRI‐based Vax.Work in our group has validated SMT technique against histology using mice with tuberous sclerosis complex and age‐matched controls.Vax and Dax, measurements in tissue with different degree of injury based on gold‐standard conventional clinical MRI with the goal of assessing clinical feasibility and translation for MS patients imaged at a 3.0 Tesla (3T) scanner.Given that axonal injury and loss are markers of MS pathology and SMT‐derived indices report on the fraction of viable axons, we hypothesize that indices derived from SMT are sensitive to different degrees of pathological changes and, thus hallmarks of neurodegenerative tissue injury in patients. To test this hypothesis, we acquired SMT in a cohort of MS patients and of age‐ and sex‐matched healthy controls (HCs). We derived This cross‐sectional study was performed as collaborative project between the Neurology and the Radiology Departments at the Vanderbilt University Medical Center (VUMC) and the University College London. The study was approved by the VUMC Institutional Review Board and each subject signed an informed written consent prior to be enrolled. All methods were performed in accordance with the relevant guidelines and regulations.Eighteen MS patients and nine age and sex‐matched HCs were consecutively included. Patients were required to be ≥6 months free from clinical relapses/steroids administration and to have no disease activity documented by a postcontrast clinical scan within the previous month Table . Exclusi3. SMT images were acquired with isotropic resolution of 2 mm. Diffusion MRI was acquired using single‐shot, SE echo planar imaging (EPI) readout, echo time (TE) = 74 msec, repetition time (TR) = 13.5 sec, 2 b shells (1000 and 2500 sec/mm2), 90 diffusion directions (45 directions on each b shell) according to a previously reported approach.b = 0 image volume was acquired with reversed phase‐encode EPI blips to correct for image distortion.Brain MRIs were performed using a Philips Achieva 3T whole‐body scanner equipped with a 32‐channel receiver head coil. All sequences were acquired without gap. Whole‐brain T1‐w and T2‐w turbo SE (TSE), T2‐w fluid attenuated inversion recovery (FLAIR) images were obtained at a resolution of 0.4 × 0.4 × 2 mmhttps://fsl.fmrib.ox.ac.uk/fsl/). Two parametric maps, Vax and Dax were fitted according to the method reported previously.https://fsl.fmrib.ox.ac.uk/fsl/). Figure For each subject, all diffusion MRI data were corrected to remove susceptibility and eddy‐current induced distortion using topup and eddy toolbox in FSL (https://mipav.cit.nih.gov). All generated masks were then overlaid on Vax, Dax, and AD parametric maps and correspondent quantities derived using mathematical tools in MIPAV.To quantify differences between various tissues types, given the well‐known variability in axonal number and diameter in different areas of the brain, anatomically matched regions of interest (ROIs) were generated Fig. . This evROIs were placed on areas of normal appearing white matter (NAWM), T2‐lesions and cBHs in patients, and in normal WM (NWM) in HCs. Tissue type classification was based on visual inspection performed by a junior investigator (GF) and confirmed by a senior investigator (FB).NAWM was defined as any area displaying normal signal on T2‐w TSE and FLAIR images. Care was taken to avoid areas of dirty WMThis tissue type classification was based on the known concepts that: 1) a considerable amount of pathology may be found in areas of MS brains appearing as “normal” on conventional MRI scans a considTo quantify differences between NAWM (patients) and NWM (HCs), ROIs were delineated in the internal capsula only (chosen as representative tract). The internal capsula was localized by two investigators (GF and FB) looking at the T2‐w images against anatomical atlases. For this last set of comparisons, care was taken that all areas had the same size which was 80 voxels.To assess the associations between overall lesion burden and SMT‐derived metrics, whole‐lesion load on T2‐w and T1‐w images was computed. To obtain lesion volume, we used the procedures previously described.For interscan variability measurements, ROIs were traced on T2‐w SE MRI randomly obtained with the first or the second scan. SMT imaging derived maps at each time point were then registered into the T2‐w SE space selected for ROI labeling using the FSL software package as described above. For each pair of scans, ROIs were selected in NAWM/NWM and in WM lesions. Care was taken that all areas had the same size which was 80 voxels. The average SMT‐ and DTI‐measures for these ROIs were then calculated. Quantities on 96 ROIS were collected in NWM, MAWM and WM lesions.Vax, Dax, and AD) was treated as a fixed‐effect factor, and a nested random effect factor for ROI and patient ID was included to take into consideration the data correlation structure. Adjusted odds ratios (OR) with corresponding 95% confidence interval (CI) and the Akaike information criterion (AIC) values were reported. Some of the original values were very small, which resulted in extreme OR values. Therefore, each variable was scaled to the degree needed to have easy‐to‐interpret OR ranges. Specifically, Vax, Dax, and AD were scaled 10 (Vax) and 10,000 (Dax and AD) times in all generalized linear mixed models. Associations among different MRI measures and between MRI and clinical variables were assessed using a Spearman's correlation.Differences in age and sex between patients and HCs were assessed using t‐test and Chi‐square test, respectively. Generalized linear mixed models for binary outcomes were used to assess differences in each of the MRI metrics between different tissues types. In these models, the type of MR measurement  and ROI (type). The nested random effect factors were subjects and scan. MRI measurements from the two scans were visualized with smoothed scatter plots. Spearman's correlation coefficients were calculated between the two scans.Interscan variability in All recruited participants tolerated the entire brain MRI scan and there were no missing data.r = 0.654, P < 0.0001 for Vax, r = 0.367, P = 0.010 for Dax, and r = 0.809, P < 0.0001 for AD). Linear mixed‐effect models showed that Vax (P = 0.337), Dax (P = 0.326) and AD (P = 0.966) values were consistently similar between the two scans. Table As represented in Figure x P = 0.36 and AD Vax  values were consistently lower in cBHs compared with T2‐lesions. Dax  and AD  values were higher in cBHs compared with T2‐lesions. Vax values decreased by 63.4 ± 45.5% in cBHs vs T2‐lesions, whereas Dax and AD values increased by 3.6 ± 7.9% and 14.1 ± 9.1%, respectively.This analysis was obtained in 209 cBHs which were compared with 209 contralateral T2‐lesions identified from nine patients. Vax and AD measures were significantly associated .In cBHs, only Vax  values were lower and AD  values higher in T2‐lesions compared with NAWM ROIs. Vax values decreased by 36.5 ± 9.7%, whereas AD values increased by 8.8 ± 0.5% in T2‐lesions compared with NAWM. Dax was 3.0 ± 9.4% higher in T2‐lesions compared with NAWM ROIs. This increment, though, did not correspond with significantly different values between the two tissues types.This analysis was obtained in 606 T2‐lesions which were compared with 606 contralateral ROIs identified from 18 patients. Dax values were significantly associated with Vax  and AD values .In this subset of lesions, This analysis was obtained in 136 NAWM ROIs which were compared with 72 NWM ROIs identified from 18 patients and all nine HCs.Vax , Dax  and AD . These nonsignificant differences corresponded to percent drops of 2.9% in Vax, and 5.4% and 5.8% increases in Dax and AD between NAWM and NWM. NAWM Vax was significantly correlated with NAWM Dax .To ensure proper anatomical correspondence, comparisons between NAWM and NWM regions was limited to areas of the internal capsula. No group‐differences were seen in Dax and Vax and 18 patients for T2‐lesions and NAWM ROIs. Significant correlations emerged between cBHs Dax and cBHs volume . None of the diffusion‐based metrics measured in T2‐lesions and NAWM correlated significantly with cBHs and T2‐lesion volume. Statistical trends were seen in the associations between T2‐lesion volume and Dax measured in T2‐lesions  and between NAWM AD and cBHs volume .This explorative analysis was limited to only the patients who contributed to the measurements, that is, nine patients for cBHs Dax and Vax and 18 patients for T2‐lesions and NAWM ROIs. We did not find any significant association between MRI and clinical metrics. A trend was seen only between T2‐lesion Vax  and T25‐WT scores.As seen for the associations with radiological metrics, this explorative analysis was limited to only the patients who contributed to the measurements. Nine patients for cBHs Vax and Dax. Although changes in Vax and Dax follow the same directions of those seen with AD, SMT offers a novel framework in that while AD depends on the diffusivity parallel to the axons and their orientation distribution, SMT fully factors out the unwanted effect of the axon orientation distribution  and provides estimates of axonal configuration, only. The removal of orientation dependency increases the specificity of the measurement to axonal integrity, which is fundamental to properly assess disease in human brains.We deliver the first clinical application of SMT as an imaging tool to probe axonal integrity in brains of patients with MS and show the feasibility of our technique for an in vivo marker of axonal damage. SMT produces two novel metrics namely This translates into the delivery of a more accurate information regarding the degree of injury of myelinated axons. The latter is important information for patients with MS since axonal injury is a key element of their physical and cognitive disability and represents an end‐stage, irreversible disease trait. Treatment strategies targeting axonal counts are much needed to arrest MS progression and an imaging biomarker accurate proxy of this count is fundamental to assess drugs effect.Vax, Dax, and AD values were found to be consistently different between cBHs and T2‐lesions; statistical analyses yielded comparable AIC, hence proving that from a statistical standpoint, the degrees of significance were comparable. However, in cBHs Vax values decreased by about 63%, whereas Dax and AD values increased only by about 4% and 14%, respectively. The magnitude of these differences points toward a different level of sensitivity to pathology. While Vax provides indirect estimates of the apparent axonal volume fraction, Dax and AD are also more sensitive to the overall lesion, intra‐ and extra‐axonal, microenvironment where several factors may modulate measurements.Vax, instead, are more reflective of viable remaining intact (myelinated) axons, irrespective of their sizes or the surrounding CSF. Differences in the degree of associations between Vax and AD or Dax values may also be intrinsic to the biophysics of these parameters. AD is sensitive to both orientation and microstructural effects, whereas Dax is only sensitive to microstructural features as the orientation distribution effect is factored out by the model. It is likely that in cBHs modifications of the orientation distribution play a larger role compared with that of microstructural changes due to the actual tissue loss and water accumulation, thus rendering AD (more than Dax) reflective of Vax values.cBHs are known to harbor a diminished number of axons,Vax values were lower and AD values higher in T2‐lesions compared with NAWM ROIs, and AICs were comparable. Vax values decreased by 36%, whereas AD values increased by 9% in T2‐lesions compared with NAWM. Dax measures were minimally higher in lesions compared with NAWM but this difference did not reach statistical significance. Dax was significantly associated with T2‐lesions Vax and AD. Such associations differ from that seen in cBHs in that Vax and Dax were positively correlated.Analyses related to T2‐lesions in comparisons to NAWM were obtained in a larger number of ROIs and patients since virtually every patient presented with lesions on T2‐w MRIs. As seen for cBHs, Vax reduction in T2‐lesions. First, our data suggest that axonal injury is not a feature of cBHs only and that, although to a less extent, chronic T2‐lesions may harbor some degree of axonal death. Second, one shall keep in mind that Vax may also be affected by myelin loss not necessarily mirrored by axonal death. Myelin degradation makes the tissue substrate less densely packed and may lead to an increase of exchange between intra‐ and extra‐axonal water, which the SMT model assumes as negligible. Untangling the effect of axonal and myelin pathology is difficult in T2‐lesions where: (1) the pathological features are more heterogeneous than in cBHs; (2) most of the axons are expected to be viable; (3) remyelination and demyelination may be tightly spatially connected. This may explain also the complex and intriguing results derived from correlation analysis. Last, in the presence of chronic inflammation and associated free water content changes in the extracellular space, the T2 relaxation time and diffusion signal coming from the extracellular compartment increase. In SMT, the higher intensity of the signal from the extracellular space will translate into a higher signal fraction (1 − Vax) or lower Vax. In the absence of compartmental T2 relaxation time data, the determination of this effect remains elusive.Three possible interpretations, not mutually exclusive, can explain the findings of Dax values between these lesions and NAWM as well as the positive associations between Vax and Dax values.We argue that the pathological heterogeneity of T2‐lesions explains the similarity in Different histopathological stages, macroscopically characterized by changes in axonal size, feature the pathway toward atrophy and consequential death.Dax and the positive, in a way “paradoxical” associations seen between Vax and Dax may be the result of these heterogeneous pathological processes along with sensitivity of Vax to both axonal and myelin density when axonal loss has not occurred.It is well‐known that all these processes, along with demyelination alone, re‐myelination, and gliosis, may co‐exist in T2‐lesions. Imaging cannot distinguish any of these pathologies but can indirectly proxy all of them by depicting changes in microstructural integrity (changes in protein content), water content (swelling), and overall axonal quantity . All these changes alter water diffusion microenvironment and eventually alter the diffusion MRI signals in potentially opposite directions. Thus, lack of end changes in Vax, Dax, and AD led to negative results though a strong trend was seen for Vax. Several factors, not necessarily mutually exclusive may explain our data. First NAWM axonal pathology may not necessarily be present in all MS patients,Differences between NAWM and NWM Vax measurements were nearly significantly different between the two groups of ROIs, whereas AD and Dax were not. The data indicate once again the ability of Vax to depict pathologies that are different and are likely measurable earlier in the disease course than those captured from Dax and AD.Notwithstanding the above considerations, it is interesting to note that Dax values and cBHs volume. In lack of other data corroborating the biological meaning of these findings, any interpretation remains limited and vulnerable. It is important to underscore that SMT metrics were derived only from a limited number of patients and lesions. On the contrary, volume measures reflect the overall lesion burden each individual patient had. This factor, in addition to clinical heterogeneity of the study cohort and its relatively small size make it not suitable to answer specific biological‐clinical questions.Of all explored associations, the only one that showed a statistically relevant (inverse) significance was that between cBHs As stated, our work lacks data regarding clinical impact of SMT‐derived metrics. While we acknowledge that this is an important limitation, we also point out that this line of research was outside the scope of our work. Assessing the ability of SMT to quantify tissue changes was our study goal and it is the first important pre‐requisite for a given sequence to be further applied on larger clinical scale. Our study is part of a larger project the goal of which is assessing the role of SMT‐derived metrics as hallmarks of neurodegenerative tissue injury and severity of neurological dysfunction.We also lack analysis of active lesions, featured by contrast enhancement and overt blood–brain barrier breakdown. This topic was also outside our initial scope of proving feasibility of SMT in patients with MS. It is the focus of future work as very important from both a biological and a technical stand point.Vax obtained using SMT. The same study also found that the intra‐axonal T2 could be dependent on the angle of the tract relative to the main magnetic field, which suggests that subject's head orientation itself could influence the results. A possible solution is to perform combined diffusion‐relaxometry measurements. In terms of clinical translation, though, one needs to be cautious as acquiring T2‐maps adds another dimension of acquisition and significantly increases the total scan time. By contrast, SMT provides a simplified and efficient means to evaluate the apparent axonal volume fraction with clinically feasible scan time, if one is mindful of the caveat that absolute values may be confounded by the multi‐compartment T2 relaxation.Another important limitation is that, except for myelin water that is invisible at the echo times used in clinical diffusion MRI scans, the SMT model assumes uniform T2 values . Although this assumption has been used extensively thus far, a recent studyIn conclusion, we propose the first clinical application of SMT in brain of patients with MS. Our results yield intriguing observations which overall testify for the applicability of this technique in patients with brain and spinal cordNone declared.


To determine the pre-procedural value of different fibrotic biomarkers and comprehensive cardiac magnetic resonance (CMR) for the prediction of poor response to ablation therapy in patients with atrial fibrillation (AF). Left atrial (LA) late gadolinium enhancement (LGE) and native LA T1 relaxation times were assessed using CMR. Plasma levels of relaxin, myeloperoxidase and serum levels of matrix metalloproteinase (MMP)-mediated cardiac specific titin fragmentation and MMP-mediated type IV collagen degradation were obtained. Poor outcome was defined by the recurrence of AF during 1-year follow-up. 61 patients were included in final analysis. Twenty (32.8%) patients had recurrence of AF. Patients with a recurrence of AF had a higher percentage of LA LGE , higher LA T1 relaxation times  and higher plasma levels of relaxin . In the multivariate Cox regression analysis, poor ablation outcome was best predicted by advanced LGE stage (hazard ratio (HR):5.487; P = 0.001) and T1 relaxation times . Pre-procedural CMR is a valuable tool for prediction of poor response to catheter ablation therapy in patients with AF. It offers various imaging techniques for outcome prediction and might be valuable for a better patient selection prior to ablation therapy. Although the underlying pathophysiology is still incompletely understood, several studies suggest that profibrotic and inflammatory processes play a pivotal role in the mechanisms of AF3. Furthermore, the development and recurrence of atrial fibrillation is tightly linked to a fibrotic remodeling of the left atrium4. As pulmonary vein ectopic activity has been linked to the initiation and maintenance of AF, pulmonary vein isolation (PVI) is used to cut the electric link between pulmonary veins and the left atrium. The procedure helps to restore normal sinus rhythm and has become a widely accepted treatment strategy in patients with paroxysmal and persistent AF4. However, as success rates of PVI differ widely, there is a special need for conclusive preprocedural parameters for the reliable identification of patients who have a low chance of ablation success and therefore might be considered not eligible for AF ablation.Atrial fibrillation (AF) remains the most common cardiac arrhythmia and is characterized by an irregular ventricular interval and the absence of distinct organized atrial activity on electrocardiogram6. In left atrial (LA) LGE CMR, the amount of contrast enhancement in the LA wall is considered to represent the volume of fibrotic tissue of the total LA wall7. A higher amount of atrial fibrotic tissue can favor atrial arrhythmogenesis7. Recently, more severe fibrosis detected via LGE CMR was also linked to an increased risk of stroke or transitory ischemic attack8. Another, newer CMR technique for noninvasive tissue characterization based on the quantitative calculation of myocardial T1 relaxation times is myocardial T1 mapping. To date, myocardial T1 mapping has been used for tissue characterization of the left ventricular myocardium and seems to be a promising new tool for the assessment of myocardial fibrosis and edema10. Several studies revealed high correlations of myocardial T1 relaxation times with histological collagen volume fraction of the left ventricle11.Recently, cardiac magnetic resonance (CMR) imaging using a late gadolinium enhancement (LGE) sequence has been described to be independently associated with the likelihood of recurrent arrhythmia after PVI13. In experimental models, matrix metalloproteinase (MMP)-mediated cardiac specific titin fragmentation (TIM) and MMP-mediated type IV collagen degradation (C4M) are a reflection of cardiac tissue remodeling, whereas relaxin seems to have anti-fibrotic properties in the development of AF17. Chronic inflammatory processes might therefore be a prequel of altered deposition of extracellular matrix in LA fibrosis, which can conclusively be visualized on CMR.Beside imaging parameters, inflammatory pathways have been described as a crucial initiator of LA fibrosis. Several inflammatory serum biomarkers, like profibrotic myeloperoxidase, are associated with a higher risk of AF recurrence after PVIThe aim of this prospective study was, therefore, to investigate the pre-procedural value of different fibrotic biomarkers and comprehensive CMR (including LGE and native T1 mapping) for the prediction of poor response to ablation therapy.The responsible ethics committee of the university of Bonn approved this study, and all subjects gave informed consent. All experiments were performed in accordance with relevant guidelines and regulations. This prospective study included patients with paroxysmal or persistent AF scheduled for first PVI by cryoballoon ablation (second generation) at our institution between February 2015 and January 2016. Patients with long standing persistent AF were excluded. All patients had transthoracic and transesophageal echocardiography prior to PVI. Blood samples and LA CMR were conducted at least 4 days prior to PVI. A 72 holter monitor test performed at 3, 6, 9 and 12 months after PVI. The study endpoint was the recurrence of AF (documented arrhythmia episodes (>30 sec)) during 1-year follow-up after a 90-day blanking period.18 : 2.18 ms; time of echo (TE): 1.02 ms; parallel imaging factor (SENSE): 2; voxel size (acquired): 2.00 × 2.00 × 8 mm; voxel size (reconstructed): 1.17 × 1.17 × 8 mm; flip angle: 35°; estimated scan duration/breath-hold: 00:15 min). For atrial (LGE) imaging a high-resolution ECG-triggered and navigator gated 3D inversion recovery was performed in transversal orientation covering the entire left atrium. Sequence parameters were as follows: acquisition matrix: 300 × 240 mm; time of repetition (TE): 3.6 ms; time of echo (TE): 1.8 ms; voxel size (acquired): 1.3 × 1.3 × 5.0 mm; voxel size (reconstructed): 0.74 × 0.74 × 2.5 mm; flip angle: 15°; estimated scan duration: 01:54 min. LGE images were acquired 15 minutes after injection of a bolus of 0.2 mmol/kg of body weight of gadobutrol . Optimal inversion time was determined by using the Look-Locker technique19.CMR scans were performed on a 1.5 Tesla CMR system . LA native T1 mapping was performed in end-systole in transversal orientation using a high-resolution 3(3)3(3)5 modified Look-Locker inversion recovery (MOLLI) acquisition schemeT1 maps were reconstructed offline using a dedicated plugin for the OsiriX DICOM viewer software . For motion correction, the LA posterior wall was manually defined via polygon regions of interests and carefully realigned throughout the MOLLI relaxometry data. Then, an exponential fitting with a maximum likelihood estimator was used to calculate the T1 maps. The following fit model was used for the magnitude data:A Rician noise distribution was assumed because of the magnitude operation. A Look–Locker correction was performed to calculate T1 based on the fit parameters T1*, A, and B. LA T1 relaxation times were extracted from the relaxation maps via regions of interest analysis.5. The total volume of positive LGE (fibrotic tissue) is calculated as a percentage of LA wall volume. Depending on the percentage of total wall enhancement patients were categorized into four fibrosis stages: Utah I (<10% fibrosis), Utah II (10–20% fibrosis), Utah III (20–30% fibrosis), and Utah IV (>30% fibrosis).For LGE analysis, the margins of the left atrium were carefully manually traced throughout all available transversal slices via multiple regions of interest analysis (width: 1.477 mm) using Image J . Positive LA enhancement on LGE images was assessed as previously described using an individual threshold for fibrosis identification17.Laboratory parameters were determined at baseline. Most parameters were evaluated in the clinical laboratory as per routine clinical practice. Relaxin-2 and myeloperoxidase were determined using commercial available solid-phase Quantikine ELISA . The concentration of MMP-mediated titin and collagen type IV degradation fragments was determined by competitive ELISAs . The measurements were performed as previously described®, Medtronic, Inc., Minneapolis, Minnesota, USA) was used. After angiography, a 28 mm second generation cryoballoon  was positioned in front of the PV ostium with best possible occlusion, controlled by fluoroscopy. Cryoenergy was applied twice for a period of four minutes each. Prior to isolation of the right superior PV (RSPV), the decapolar catheter was removed from the coronary sinus and positioned in the superior vena cava for continuous stimulation of the phrenic nerve during application of cryoenergy. Recognition of diminishing movements of the diaphragm during fluoroscopy led to instantaneous termination of cryoapplication in the RSPV.Venous access for PVI was obtained through the right femoral vein. Having positioned a decapolar catheter over a 7 F sheath in the coronary sinus, next a single transseptal puncture (Brockenbrough technique) was performed under fluoroscopic guidance. For selective angiography of the individual pulmonary veins a 15 F sheath  advanced in the individual targeted PV. If remaining ostial PV potentials were recorded, the respective vein was treated again with the cryoballoon. During the procedure patients were continuously anticoagulated with heparin (targeted activated clotting time: 350 s). After the procedure, pericardial effusion was excluded via transthoracic echocardiography. The following day a 12-lead ECG was recorded before discharge from hospital. Anticoagulation was managed according to guideline recommendationst test  or the Mann–Whitney U test  was used for comparison of continuous variables between 2 different groups. Dichotomous variables were compared using the χ2 test (with a cell count >5) or Fisher exact test (with a cell count ≤5). Correlation analysis was performed using Spearman’s rank correlation coefficient. Significant independent predictors of AF recurrence were analyzed by univariate and subsequent multivariate Cox regression analysis. Results are displayed as adjusted hazard ratio (HR) with 95% confidence interval (CI). The level of statistical significance was set to P < 0.05.Statistical analysis was performed using SPSS Statistics 22.0  and MedCalc 11.0 . Patient characteristics are presented as mean ± standard deviation or as absolute frequency. Continuous variables were checked for normal distribution. The independent 2-sample Student A total of 71 patients were enrolled in this study. 10 (14.1%) patients were excluded due to missing data or poor CMR quality  of all CMR scan were performed in sinus rhythm. The percentage of LA wall enhancement on LGE CMR was significantly greater in the patient group with AF recurrence compared to the group without recurrence  . Patients with recurrence of AF had also slightly higher C3 values . No significant group differences were found for myeloperoxidase  between both groups. Serum levels of MMP-mediated cardiac specific titin and MMP-mediated type IV collagen degradation fragments did not significantly differ between both groups (see Table Patients with increased LA LGE enhancement (Utah stage III-IV) had higher levels of myeloperoxidase  and a tendency of higher levels of relaxin  compared to patients with Utah stage I-II. The white blood count  as well as the neutrophils  were significantly associated to higher levels of LA wall enhancement.In the univariate Cox regression analysis T1 relaxation time (HR 1.008 (95% CI: 1.003–1.012); P < 0.001) and higher fibrosis stages on LGE CMR (HR 5.811 (95% CI: 2.105–16.038); P = 0.001) were associated with arrhytmia recurrence. Also, white blood cell count (HR 1.370 (95% CI: 1.038–1.809); P = 0.026) was associated with arrhythmia recurrence. In the multivariate model, only T1 relaxation time (HR 1.007 (95% CI: 1.003–1.011); P = 0.001) and higher fibrosis stages on LGE CMR (HR 5.487 (95% CI: 1.920–15.680); P = 0.001)  both CMR markers of atrial fibrosis (percentage of positive LGE and T1 relaxation times) were significantly elevated in patients with recurrence of AF, (2) some inflammatory and fibrotic biomarkers including anti-fibrotic relaxin also allowed a group discrimination between patients with and without recurrence of AF, and (3) on multivariate analysis T1 relaxation times and higher fibrosis stages were the only independent predictors of poor outcome following ablation therapy.4. The development of cardiac and atrial fibrosis is characterized by an increase in collagen and other extracellular matrix components21. On LGE CMR, an extracellular contrast agent accumulates in areas with an increased extracellular compartment without entering the myocardial cells and thus focal and patchy areas of atrial and myocardial fibrosis can be visualized1. Recently, a prospective multicenter trial (the DECAAF study) reported that atrial tissue fibrosis estimated by LGE CMR was independently associated with the recurrence of AF following PVI6. Especially patients with higher fibrosis stages on LGE images (Utah stage III (20–30% fibrosis) and Utah stadium IV (>30% fibrosis)) had an increased risk of recurrence. Another study in 426 patients, partly confirming the results of the DECAAF study, showed that recurrent arrhythmia occurred mainly in patients with higher atrial enhancement on LGE images (recurrence of AF in 71.4% of patients with Utah stage IV)7. In our study, we could achieve similar LGE CMR results: higher fibrosis stages (Utah stage III and IV) were independently associated with the risk of PVI failure (HR: 5.487). Our study results therefore support those previous studies showing that pre-existing fibrosis and scarring on LGE CMR are independent predictors of ablation procedure failure and arrhythmia recurrence. This may be because patients with advanced structural fibrotic remodeling, as indicated by LGE CMR, are more likely to have extensive fibrillatory circuits that are difficult to interrupt by PVI, compared to patients with a lower degree of fibrosis/AF substrate. Thus, interruption of the fibrillatory pathways in the early stages of fibrosis seems to be crucial for the success of PVI.The presence of LA fibrosis has been postulated as a major cause of conduction abnormalities underlying the initiation and maintenance of AF10. Myocardial T1 relaxation times can be assessed both in the native tissue and after the administration of CMR contrast media (yielding post-contrast T1 relaxation times)10. With both T1 mapping approaches it is possible to detect diffuse myocardial fibrosis, which has been demonstrated in multiple histological validation studies of the left ventricle11. Native T1 values are typically increased in diffuse fibrosis, whereas post-contrast T1 values are decreased (due to the increased accumulation of extracellular gadolinium in areas of fibrosis)11. The possibility of T1 mapping to detect diffuse fibrosis might be an advantage compared to qualitative/ semi-qualitative LGE imaging, in which the assessment of fibrotic changes might be hindered in cases of diffuse disease . Compared to LGE imaging for LA fibrosis quantification, T1 mapping has some more advantages: the technique does not require a special software for image analysis, the measurements are less time consuming, and no individual thresholds have to be defined to separate healthy from fibrotic myocardium. Previous studies dealing with T1 relaxation times in patients with AF mainly focused on diffuse left ventricular fibrosis23. In these studies, post-contrast T1 relaxation times were identified to be decreased in patients with AF compared to healthy controls indicating an association between AF and adverse ventricular remodeling22. McLellan et al. reported shorter post-contrast left ventricular T1 relaxation times to be associated with reduced freedom of AF after PVI22. However, another study found left ventricular T1 relaxation time not to be associated with the recurrence of AF after ablation23.Another CMR technique which has been described to reliably assess myocardial fibrosis is myocardial T1 mapping. T1 mapping allows for a direct myocardial signal quantification according to myocardium’s longitudinal relaxation timeet al. found post-contrast LA T1 relaxation times to be shorter in patients with AF compared to healthy volunteers24. Furthermore, lower LA T1 relaxation times were also associated with lower bipolar LA voltage measurements24. Ling et al. demonstrated that post-contrast LA T1 relaxation times of <230 ms were associated with a higher risk of arrhythmia recurrence25. In contrast to the study of Ling et al.25, we evaluated LA T1 relaxation times in a more complex multivariate model, which also included several more established (e.g. LA LGE and myeloperoxidase) markers of LA fibrosis and fibrogenesis. Despite this more complex regression model, LA T1 relaxation times were independently associated with PVI failure in our study. This suggests that the assessment of LA T1 relaxation values might be a robust new parameter for the evaluation of LA tissue composition.To date, only few studies have applied the T1 mapping technique to the left atrium. Beinart et al.25, LA T1 mapping was performed native  in our study. In patients with recurrence of AF native LA T1 relaxation times were significantly prolonged. The acquisition of native T1 maps is also associated with some major advantages: First, native T1 mapping avoids possible confounding factor of post-contrast T1 mapping like renal function impairment, hematocrit variations and delay time in measurement after contrast administration26. Second, native T1 mapping can also be performed in patients with severe kidney disease and contrast medium allergy. This may be of great importance because the currently proposed CMR protocols for evaluation of LA wall fibrosis (e.g. LGE imaging and post-contrast T1 mapping) are restricted to patients without contraindications for the use of gadolinium-based contrast agents. Another novel finding of our study is that we showed a significant correlation between LA wall enhancement on LGE imaging and LA T1 relaxation times suggesting that both parameters are capable of LA wall fibrosis detection and quantification. In contrast to time consuming LGE LA imaging6, a native T1 map can be acquired during a single breath-hold18, which might be another advantage, as it would significantly reduce examination time.Furthermore, in contrast to the study of Ling 27. Several inflammatory pathways regulate the homogeneity of the atrial extracellular compartment and are tightly linked to the development of atrial fibrosis27. In our study, we found an elevated white blood cell count, a well-established marker of systemic inflammation, in patients with recurrence of AF. These results are in line with multiple previous studies, which also described elevations in white blood cell count and an increased inflammatory cell infiltration in the atrial myocardium in the presence of AF29. Letsas KP et al. also reported the white blood cell count to be significantly associated with AF recurrence after ablation therapy28. In our study, white blood cell count was associated with the recurrence of AF only in the univariate regression analysis, but did not reach the level of statistical significance in the multivariate model, possibly due to the strong effect of imaging parameters.Clinical investigations have reported multiple associations between the vulnerability to AF and increased biomarkers of inflammation12. In animal models, administration of myeloperoxidase is directly linked to atrial fibrotic tissue remodeling12. In patients with paroxysmal AF, higher levels of myeloperoxidase are an independent predictor of AF recurrence (HR: 2.12)13. In our mixed patient population with paroxysmal and persistent AF, however, we could not reproduce these results. We also tested plasma levels of MMP-mediated protein degradation fragments for the prediction of poor response after PVI. MMPs are a family of functionally related enzymes that cleave matrix components and can promote fibrotic myocardial matrix remodeling30. In our cohort, MMP-mediated titin and type IV collagen degradation were not associated with an unfavorable outcome after PVI. On the other hand, we observed higher relaxin levels in patients with AF recurrence. In animal models, relaxin has been described to reduce the susceptibility to AF after myocardial infarction and furthermore can reverse fibrosis in aged rats16. Interestingly, our data suggests that relaxin seems to be upregulated in patients with higher fibrosis stages. Although relaxin did not allow a prediction of AF recurrence after ablation therapy, the anti-inflammatory and anti-fibrotic properties of relaxin warrants further investigations.Myeloperoxidase has been described as a progenitor of AF induction that is increased in humans with AF7 and associations of LA T1 mapping with left atrial voltage25, indicating that the presented CMR techniques are capable to measure LA myocardial fibrosis. MOLLI T1 mapping have been demonstrated to be sensitive to heart rate and rhythm31, which could have influenced some measurements, especially in patients without sinus rhythm. Because of the relatively small LA wall thickness and the limited spatial resolution of current CMR techniques, partial volume effects may have led to a non-physiological spread of CMR values when the blood pool or pericardial fat signal intensities might have been included in some cases. Higher resolution CMR imaging will be acquired in future to facilitate a more detailed and comprehensive atrial tissue characterization. Because of the small sample size and the single-center design of the study, further prospective studies are necessary to substantiate the results of this study.In this study, a systematic endomyocardial biopsy or LA voltage mapping as a reference standard of fibrosis assessment was not performed. Also no previous study correlated LA T1 mapping with histologic fibrosis analysis. However, previous studies reported associations of LGE CMR with histological fibrosis analysisIn this study, we could show that CMR markers of atrial fibrosis (percentage of positive LGE and T1 relaxation times) were significantly elevated in patients with recurrence of AF. Both parameters were independent predictors of poor outcome following ablation therapy. Pre-procedural CMR seems to be a valuable tool for prediction of poor response to catheter ablation therapy in patients with AF. It offers various imaging techniques for outcome prediction and might be valuable for a better patient selection prior to ablation therapy.


N-oxide (TMAO) alone could acutely alter cardiac contractile function on a beat-to-beat basis. METHODS/STUDY POPULATION: CD1 adult mouse hearts were extracted, attached to a force transducer, oxygenated, and paced within an organ bath. Changes in contractility were measured after pipetting or reverse perfusing TMAO through the aorta via a modified Langendorff apparatus to facilitate TMAO delivery into the myocardium. To determine if our findings translated to the human heart, we performed contractility experiments using human right atrial appendage biopsy tissue retrieved during cardiopulmonary bypass procedures. To investigate whether TMAO alters contractile rate, in a separate series of experiments, the atria and sinoatrial node of isolated hearts were kept intact to allow for spontaneous beating without artificial pacing and were treated with TMAO or vehicle. In addition, intracellular calcium measurements were performed on spontaneously beating embryonic rat cardiomyocytes after TMAO or vehicle treatment. RESULTS/ANTICIPATED RESULTS: We found acute exposure to TMAO, diluted into the organ bath, increased average contraction amplitude 20% and 41% at 300 µM and 3000 µM, respectively . Langendorff reverse perfusion of mouse hearts ex vivo with 300 µM TMAO generated an even greater response than nonperfusion peripheral exposure and increased isometric force 32% . Consistent with what we observed in mouse hearts, incubation of human atrial muscle tissue with TMAO at 3000 µM increased isometric tension 31% compared with vehicle . TMAO treatment (3000 µM) also increased average beating frequency of ex vivo mouse hearts by 27% compared with vehicle  and increased the spontaneous beating frequency of primary rat cardiomyocytes by 13% compared with vehicle treatment . DISCUSSION/SIGNIFICANCE OF IMPACT: TMAO, at pathological concentrations, directly increases the force and rate of cardiac contractility. Initially, these inotropic and chronotropic effects may be adaptive during CKD; however, chronic increases in isometric tension and beating frequency can promote cardiac remodeling and heart failure. Further translational studies are needed to understand the intricate relationship between the microbiome, kidneys, and heart and to examine if TMAO represents a therapeutic target for reducing cardiovascular mortality in CKD patients.OBJECTIVES/SPECIFIC AIMS: The objective of this study was to determine if trimethylamine


Pd/Pa) is a non-hyperaemic physiological index to assess the functional severity of coronary stenoses. Studies comparing Pd/Pa with fractional flow reserve (FFR) show superior diagnostic efficiency for myocardial ischaemia. Nevertheless, a direct comparison regarding long-term clinical outcomes is still not available. The present observational study compared the prognostic value of Pd/Pa and FFR for major adverse cardiac events (MACE) during a 10-year follow-up period after deferral of revascularisation.The distal coronary-to-aortic pressure ratio  in which revascularisation was deferred with intracoronary pressure and flow measurements during the resting and hyperaemic state. Long-term follow-up (median: 11.8 years) was performed to document the occurrence of MACE, defined as a composite of cardiac death, myocardial infarction and target vessel revascularisation.Pd/Pa with long-term MACE was similar to that of FFR . In the presence of disagreement between Pd/Pa and FFR, normal Pd/Pa was generally associated with high coronary flow reserve (CFR) and a favourable clinical outcome, whereas abnormal Pd/Pa was generally associated with CFR around the ischaemic cut-point and an impaired clinical outcome, regardless of the accompanying FFR value.The study population comprised angiographically intermediate coronary stenoses, with a mean diameter stenosis of 53 ± 8%, and intermediate physiological severity with a median FFR of 0.82 . The association of Pd/Pa provides at least equivalent prognostic value compared with FFR. When Pd/Pa disagreed with FFR, the baseline index conferred superior prognostic value in this study population.The present study suggests that The online version of this article (10.1007/s12471-020-01365-6) contains supplementary material, which is available to authorized users. Pd/Pa) demonstrates a continuous and independent relationship with subsequent long-term clinical outcomes.The distal coronary-to-aortic pressure ratio , but exceeds FFR as a risk stratification tool at their contemporary clinical cut-off values.The prognostic value of Pd/Pa disagreed with FFR, Pd/Pa conferred superior prognostic value in this study population.When Pd/Pa) and the instantaneous wave-free ratio (iFR) were (re-)introduced with the aim of simplifying the use of coronary physiology in daily clinical practice by enabling its assessment during resting conditions , and compared with Student A total of 228 patients (299 stenoses) were included. Revascularisation was deferred in 159 patients, in 154 of whom (183 stenoses) resting and hyperaemic coronary pressure and flow velocity data and long-term follow-up were available. In patients with multiple stenoses, one was chosen at random for MACE analyses, which consequently included 154-patients with 154 stenoses. Median follow-up in these patients was 11.8 years . Mean age was 60 ± 11 years and 71% of patients were male. Additional baseline characteristics are depicted in Tab. Pd/Pa of 0.94  and median CFR of 2.5 . Stenoses were haemodynamically significant in 43.5% and 34.4% of cases according to FFR and Pd/Pa, respectively. Angiographic and physiological characteristics are depicted in Tab. The study population comprised angiographically intermediate stenoses, with a mean diameter stenosis of 53 ± 8%, and intermediate physiological severity with a median FFR of 0.82  , p = 0.033; Pd/Pa-sHR: 0.80 (95% CI: 0.67–0.96), p = 0.014] , of which 25% of the stenoses (38 out of 154) were concordant abnormal, and 47% of stenoses (72 out of 154) were concordant normal. Pd/Pa disagreed with FFR in 29% of stenoses (44 out of 154), and was characterised by abnormal FFR and normal Pd/Pa in 19% of stenoses (29 out of 154) and by normal FFR and abnormal Pd/Pa in 10% of stenoses (15 out of 154) .Pd/Pa and FFR (dis)agreement .CFR was significantly different across the four quadrants of ent Tab. . A normaPd/Pa demonstrates a continuous and independent relationship with subsequent long-term clinical outcomes which is at least equivalent to that of FFR, and that Pd/Pa exceeds FFR as a risk stratification tool at the contemporary clinical cut-off values. When discordance with FFR occurs, Pd/Pa may therefore confer superior clinical value.The current article is the first to document that Pd/Pa over FFR at contemporary cut-offs may be explained by a better agreement of Pd/Pa with coronary flow. Our observations support those of previous studies that demonstrated a better relationship between resting indices and Doppler-derived CFR than for FFR and Doppler-derived CFR [Pd/Pa may occur on the basis of a normal Pd/Pa value that decreases to abnormal FFR values at hyperaemia due to a large increase in coronary flow with a normal CFR. Such stenoses are considered non-flow-limiting, and likely have excellent clinical outcomes when managed medically [Pd/Pa may occur in combination with a normal FFR when a stenosis may coexist with an exhausted CFR as a result of compensatory vasodilation during resting conditions to maintain resting perfusion. The abnormal Pd/Pa may only decrease to normal FFR values due to the limited increase in coronary flow from baseline to hyperaemia. The optimal management of vessels exhibiting this haemodynamic pattern remains a matter of debate [Pd/Pa has better agreement with invasively measured coronary flow than FFR [Pd/Pa has superior prognostic value when there is disagreement with FFR.The superior prognostic relevance of resting ived CFR , 6, 7. Iived CFR , 9, 15. edically , 18. On f debate . Since mf debate . This isf debate , and Pd/than FFR , this ma< 0.65. Similarly, a recent patient-level meta-analysis on the prognostic value of FFR identified an optimal 0.67 FFR threshold for clinical outcomes [Importantly, our observation that there was no difference in clinical outcomes between FFR-positive and FFR-negative cases might wrongly be interpreted to be in contrast with the findings from FAME  and FAME II , 21. FAMoutcomes . These f< 0.02 are smaller than the variability of the FFR measurement itself and, therefore, are considered clinically irrelevant [The relatively small sample size limits the statistical power and the strength of the conclusions, especially for the discordant groups. We used intracoronary administration of 20–40 µg of adenosine, which remains a subject for debate. However, it has been documented that the observed FFR is already within 0.02 of its minimal value at intracoronary adenosine dosages above 23 µg , FFR difrelevant , and by relevant . Additiorelevant , 27.Pd/Pa demonstrates a continuous and independent relationship with subsequent long-term clinical outcomes which is at least equivalent to that of FFR, and suggests that Pd/Pa exceeds FFR as a risk stratification tool at its contemporary cut-off value.The present study documents that Instantaneous wave-free ratio (iFR) sub-analysis: long-term prognostic implications of iFR compared with FFR


Troponin and B-type natriuretic peptide (BNP) concentrations are associated with cardiovascular risk in stable patients. Understanding their determinants and identifying modifiable clinical targets may improve outcomes. We aimed to establish clinical and cardiac determinants of these biomarkers.This was a prespecified substudy from the randomised Scottish Computed Tomography of the Heart trial, which enrolled patients 18–75 years with suspected stable angina between 2010 and 2014 (NCT01149590). We included patients from six centres in whom high-sensitivity troponin I and BNP were measured (Singulex Erenna). Patients with troponin >99th centile upper reference limit (10.2 ng/L) or BNP ≥400 ng/L were excluded to avoid inclusion of patients with myocardial injury or heart failure. Multivariable linear regression models were constructed with troponin and BNP as dependent variables.In total, 885 patients were included; 881 (99%) and 847 (96%) had troponin and BNP concentrations above the limit of detection, respectively. Participants had a slight male preponderance , and the median age was 59.0 (IQR 51.0–65.0) years. The median troponin and BNP concentrations were 1.4 (IQR 0.90–2.1) ng/L and 29.1 (IQR 14.0–54.0) ng/L, respectively. Age and atherosclerotic burden were independent predictors of both biomarkers. Male sex, left ventricular mass and systolic blood pressure were independent predictors of increased troponin. In contrast, female sex and left ventricular volume were independent predictors of increased BNP.Troponin and BNP are associated with coronary atherosclerosis but have important sex differences and distinct and contrasting associations with CT-determined left ventricular mass and volume.NCT01149590; Post-results. The diagnostic and prognostic application of myocardial-specific plasma proteins is widely accepted in current practice. Two such cardiovascular biomarkers are high-sensitivity cardiac troponin and B-type natriuretic peptide (BNP). Although developed for use in specific populations, both are recognised to be important indicators of adverse prognosis among stable patients, even in the absence of established cardiac disease.Cardiac CT is a valuable investigation that is widely used for the diagnosis of coronary artery disease. However, it can also provide an assessment of left ventricular mass and volume, both of which are associated with elevated biomarker concentrations.In this biomarker substudy of the Scottish Computed Tomography of the Heart (SCOT-HEART) trial, we aimed to establish the clinical and cardiac determinants of plasma high-sensitivity cardiac troponin I and BNP concentrations in patients presenting with stable chest pain. We hypothesised that, in addition to recognised clinical determinants, ventricular mass and volume as determined by cardiac CT would be associated with higher biomarker concentrations.2) or acute coronary syndrome within 3 months were excluded. All patients underwent routine clinical evaluation. A clinical diagnosis and management plan were documented prior to recruitment. Eligible patients were randomised 1:1 to receive routine care or routine care plus CT coronary angiography (CTCA).This is a post-hoc analysis of the open-label, randomised SCOT-HEART trial. The trial design, primary analysis and 5-year outcomes have been published.For this substudy, we included patients who had been referred from six centres for their allocated CTCA in Edinburgh n=1317). As this study aimed to characterise the determinants of baseline cardiac biomarkers in stable patients without acute myocardial injury or heart failure, patients with troponin concentrations >99th centile upper reference limit (10.2 ng/L) (n=29) or BNP ≥400 ng/L (n=11)17. As thThe methods used to perform and to analyse coronary findings from CTCA have been reported.Cardiac CT assessments of myocardial mass and volume are validated and readily performed. Older protocols used retrospective electrocardiographic gating; however, prospective gating is now routine, with image acquisition performed in mid-diastole. Although this limits the available phases, mid-diastolic left ventricular mass measurements correlate well with other phases and have prognostic value.2 for men and >63.8 g/m2 for women—CT-specific thresholds with prognostic value.Using automated software , left ventricular myocardial contours were detected during mid-diastole (75% phase or nearest acquired) in two planes and 0.7 mm slices and manually adjusted to ensure accurate borders, allowing calculation of left ventricular volume and myocardial volume . Corrections for mid-diastolic acquisition were then appliedTroponin was measured using the Erenna high-sensitivity cardiac troponin I assay . The limit of detection is 0.1 ng/L with a 99th centile upper reference limit of 10.2 ng/L and a limit of quantification  of 0.4 ng/L.2 transformation. For descriptive purposes baseline characteristics are reported as median (IQR) according to troponin and BNP quantiles. Body mass index, systolic blood pressure, diastolic blood pressure, CT-adapted Leaman score, indexed left ventricular mass, indexed left ventricular volume and creatinine were log-transformed as a linearising transformation. Missingness was low, apart from creatinine  and indexed left ventricular volume . To avoid introducing bias by using complete case analysis, missing values were estimated by multivariable imputation by chained equations. Subsequent analyses were conducted using a single imputed value for each missing value. In a sensitivity analysis, the pooled parameters for the final models were also determined  had a troponin concentration >99th centile upper reference limit and 11 (1%) had a BNP >400 ng/L. After excluding these patients and patients with missing BNP data, 885 patients were included. The median troponin concentration was 1.4 (0.9–2.1) ng/L. The median BNP concentration was 29.1 (14.0–54.0) ng/L . PatientCoronary CT angiography demonstrated normal coronary arteries in 309 (35%) patients, while 401 (45%) patients had stenoses of at least 50% . The med2 for men and 62.6 (56.7–69.9) g/m2 for women. Nearly half  of patients met sex-specific CT criteria for left ventricular hypertrophy. The median indexed left ventricular volume was 64.6 (56.6–71.3) mL/m2 for men and 62.1 (56.5–68.0) mL/m2 for women.The median indexed left ventricular mass was 78.1 (71.1–86.1) g/m2=0.30, p<0.001) and BNP  were included. Increasing age and atherosclerotic burden as assessed by CT-adapted Leaman score were independent predictors for increased troponin and BNP concentrations. Male sex and indexed left ventricular mass were predictors of increased troponin, in addition to hypertension, systolic blood pressure and body mass index, but not BNP. In contrast, female sex and indexed left ventricular volume were predictors of increased BNP but not troponin. Of note, creatinine was a univariable predictor of increased troponin, but the association no longer remained after adjustment for other variables. Conversely, creatinine was a multivariable predictor of lower BNP. The biomarker-specific nature of these associations was confirmed on multivariable analysis of variance testing of the full model where both biomarkers were included as dependent variables (bivariate multivariable regression). Furthermore, after standardising continuous variables, indexed left ventricular mass and volume provided the largest relative contribution to the explained variance within the troponin and BNP multivariable models, respectively, apart from age, which demonstrated the highest coefficient for both models ; the determinants of biomarker concentrations in these contexts therefore remain uncertain. Nevertheless, SCOT-HEART was pragmatic in design, enrolling a cohort broadly representative of real-world populations with suspected stable angina. Second, without serial plasma samples, we cannot be certain that biomarker values reflect true baseline concentrations. However, participants were recruited in a stable outpatient setting and we excluded individuals with troponin concentrations above the 99th centile and BNP >400 ng/L,There are several limitations. First, key exclusion criteria for the study included age >75 years or severe renal impairment  concentrations are associated with greater risk of cardiovascular events in individuals with and without established cardiac disease.Plasma concentrations in stable outpatients may be attributable to pathophysiological processes including hypertension, coronary atherosclerosis and left ventricular dysfunction, but clinical determinants are not fully characterised.We demonstrate the association between overall plaque burden as assessed by CT coronary angiography (CTCA) and troponin and BNP concentrations.Importantly, we describe sex differences and contrasting associations with left ventricular mass and volume.We also demonstrate the ability of prospectively gated CTCA performed primarily for coronary artery assessment to provide additional information regarding ventricular mass and volume.Although plasma troponin and BNP have prognostic value in stable patients, an understanding of their determinants—and specifically, modifiable determinants—is necessary to add clinical utility.With this knowledge, these plasma biomarkers have the potential to act as simple surrogate markers of treatment efficacy for targeted disease-modifying therapies.