Relationships Between Left Ventricular Structure and Function According to Cardiac MRI and Cardiac Biomarkers in End-Stage Renal Disease

Cardiac remodeling in middle-aged endurance athletes: relation between signal-averaged electrocardiogram and LV mass

The relationship between structural and electrical remodeling in the heart, particularly after long-standing endurance training, remains unclear. Signal-averaged electrocardiogram (SAECG) may provide a more sensitive method to evaluate cardiac remodeling than a 12-lead electrocardiogram (ECG). Accurate measures of electrical function (SAECG filtered QRS duration (fQRSd) and late potentials (LP) and left-ventricular (LV) mass (cardiac magnetic resonance, CMR) can allow an assessment of structural remodeling and QRS prolongation. Endurance athletes (45-65 yr old, >10 yr of endurance sport), screened to exclude cardiac disease, had standardized 12-lead ECG, SAECG, resting echocardiogram (ECHO), and CMR performed. SAECG fQRSd was correlated with QRS duration on the 12-lead ECG, and ECHO and CMR-derived LV mass. Participants (n = 82, 67% male, mean age: 54 ± 6 yr, mean V̇o_2max: 50 ± 7 mL/kg/min) had a CMR-derived LV mass of 118 ± 28 g/m² and a fQRSd of 112 ± 8 ms (46% had abnormal fQRSd (>114 ms), and 51% met clinical threshold for abnormal SAECG). fQRSd was positively correlated with the 12-lead ECG QRS duration (r = 0.83), ECHO-derived LV mass (r = 0.60), CMR-derived LV mass (r = 0.58) and LV end-diastolic volume (r = 0.63, P < 0.001 for all). fQRSd had higher correlations with ECHO and CMR-derived LV mass than 12-lead ECG (P < 0.0008 and P < 0.0005, respectively). In conclusion, in a healthy cohort of middle-aged endurance athletes, the SAECG is often abnormal by conventional criteria, and is correlated with structural remodeling, but CMR evaluation does not indicate pathologic structural remodeling. SAECG fQRSd is superior to the 12-lead ECG for the electrocardiographic evaluation of LV mass.NEW & NOTEWORTHY Study findings indicate that a positive correlation exists between electrical (SAECG fQRSd) and structural indices (LV mass) in middle-aged endurance athletes with normal physiological LV adaptation, in the absence of known cardiac pathology. SAECG fQRSd may also provide an alternative, superior method for identifying increased LV mass compared to other 12-lead ECG criteria.

Cardiac Imaging in Dialysis Patients

There is a well-established yet unexplained high prevalence of cardiovascular morbidity and mortality in individuals with end-stage kidney disease receiving dialysis. Potential causes include changes in cardiac structure and function, with increased left ventricular mass index as the best established cardiac structural change associated with this increase in mortality. However, in recent years, new echocardiographic and cardiac magnetic resonance imaging techniques have emerged that may provide novel markers that may better explain the mechanisms underlying the cardiovascular morbidity and mortality observed in end-stage kidney disease. This review outlines advances in cardiac imaging and the current status of imaging modalities, including echocardiography, cardiac magnetic resonance imaging, and cardiac positron emission tomography, to identify dialysis patients at high risk for cardiovascular mortality.

Evaluation of left atrial remodeling in kidney transplant patients using cardiac magnetic resonance imaging

BACKGROUND

Increased left atrial (LA) size predicts cardiovascular events in patients with end-stage kidney disease. There is a paucity of data on LA changes after kidney transplantation (KT). Accordingly, we used cardiac magnetic resonance imaging (CMR) to evaluate LA remodeling after KT, and examined its relationship with left ventricular (LV) measurements, blood pressure and cardiac biomarkers.

METHODS

In this prospective multi-center cohort study, 39 pre-transplant dialysis patients underwent KT and 42 eligible transplant recipients remained on dialysis. CMR, blood pressure and serum measurements for N-terminal pro b-type natriuretic peptide (NT-proBNP), high sensitivity C-reactive protein (hsCRP), and growth differentiation factor-15 (GDF-15) were performed at baseline and 12 months.

RESULTS

After 12 months, there were no significant changes in LA end-systolic volume index, LA end-diastolic volume index, or LA ejection fraction (LAEF) within the KT or dialysis group; changes over time did not differ between the 2 groups (all p > 0.25). At baseline and over 12 months, LA volumes and LAEF positively correlated with LV volumes and mass while LAEF positively correlated with LV function. Changes in LA volumes also positively correlated with NT-proBNP and systolic blood pressure (sBP) while LAEF negatively correlated with NT-proBNP. GDF-15 correlated with LA measurements at baseline but not in 12-month changes. hsCRP did not correlate with any LA measurements.

CONCLUSIONS

LA volumes and function as measured by CMR did not change significantly over 12 months post-KT. There were significant associations between LA and LV remodeling, NT-proBNP and sBP, suggesting common underlying pathophysiological mechanisms.

Predictors of Change in Left-Ventricular Structure and Function in a Trial of Extended Hours Hemodialysis

BACKGROUND

Myocardial pathology is common in patients undergoing hemodialysis. To explore the effects of differing aspects of dialysis treatment on its evolution, we examined the impact of change in markers of volume status, hemodynamics and solute clearance on left ventricular (LV) parameters in a randomized trial of extended hours dialysis.

METHODS AND RESULTS

A Clinical Trial of IntensiVE (ACTIVE) Dialysis randomized 200 patients undergoing hemodialysis to extended dialysis hours (≥ 24 hours/week) or standard hours (12-18 hours/week) for 12 months. In a prespecified substudy, 95 participants underwent cardiac magnetic resonance imaging (CMR) at baseline and at the study's end. Generalized linear regression was used to model the relationship between changes in LV parameters and markers of volume status (normalized ultrafiltration rate and total weekly interdialytic weight gain), hemodynamic changes (systolic and diastolic blood pressure) and solute control (urea clearance, dialysis hours and phosphate). Randomization to extended hours dialysis was not associated with change in any CMR parameter. Reduction in ultrafiltration rate was associated with reduction in LV mass index (P = 0.049) and improved ejection fraction (P = 0.024); reduction in systolic blood pressure was also associated with improvement in ejection fraction (P = 0.045); reduction in interdialytic weight gain was associated with reduced stroke volume (P = 0.038). There were no associations between change in urea clearance, phosphate or total hours per week and CMR parameters.

CONCLUSIONS

Reduction in ultrafiltration rate and blood pressure are associated with improved myocardial parameters in hemodialysis recipients independently of solute clearance or dialysis time. These findings underscore the importance of fluid status and related parameters as potential treatment targets in this population.

Expression of miRNAs-122, -192 and -499 in end stage renal disease associated with acute myocardial infarction

INTRODUCTION

New diagnostic tools are needed to accurately detect acute myocardial infarction (AMI) in patients with end stage renal disease (ESRD) presenting with ischemic chest pain. We aimed in this study to investigate circulating miR-122, -192 and -499 expression levels in patients with AMI on top of ESRD and evaluate the potential of these miRNAs as blood-based biomarkers for AMI in patients with ESRD.

MATERIAL AND METHODS

The study included 80 ESRD patients without AMI, 80 patients with ESRD associated with AMI and 60 healthy subjects. Assessment of microRNAs was done using SYBR Green based real-time PCR.

RESULTS

Levels of miR-122 were 28-fold and 20-fold higher in controls than in ESRD patients with or without AMI respectively (p < 0.001), while no differences were detected between the two patient groups (p = 0.9). Levels of miR-192 showed a marked increase in ESRD patients with and without AMI compared to the control group (> 500-fold, > 8000-fold respectively, p ≤ 0.001). Patients who developed AMI had lower expression than ESRD patients without AMI (p < 0.001). Non-significant miR-499 elevation was found in ESRD patients without cardiac disease compared to the control group, while highly significant elevation of miR- 499 was demonstrated in ESRD patients who developed AMI compared to other ESRD patients and the control group (> 100-fold, > 350-fold respectively, p = 0.001).

CONCLUSIONS

Altered expression of miR-122 and -192 may contribute in pathogenesis of ESRD. MiR-192 and -499 may serve as potential biomarkers for AMI in ESRD. Further studies are needed to correlate these miRNAs with disease progression and outcome.

Prognostic value of high-sensitive cardiac troponin I in asymptomatic chronic hemodialysis patients

INTRODUCTION

Increased levels of cardiac troponins (cTn) are a hallmark of acute myocardial infarction (AMI), along with symptoms and electrocardiographic (ECG) changes. Stably elevated cTn concentrations are frequently observed in asymptomatic patients with chronic kidney disease (CKD) and/or on hemodialysis (HD); the meaning of this elevation, as assessed by conventional techniques, remains unclear. Aim of our study was to evaluate the clinical significance of cTnI levels in asymptomatic HD patients by employing a newer high-sensitive cTnI (hs-cTnI) assay.

METHODS

We enrolled 49 patients undergoing regular HD treatment for more than 3 months; all patients were asymptomatic for chest pain and had no history of acute coronary syndrome in the past 2 months. For every patient we measured hs-cTnI, cTnI and brain natriuretic peptide (BNP) before initiation of one HD session at baseline (T0), after 3 (T1) and 9 months (T2). Demographic, anamnestic, dialytic and echocardiographic characteristics of the examined population were evaluated. We also recorded the number of cardiovascular events from T0 to 12 months after T2.

RESULTS

Fifteen patients were lost to follow-up: 6 died, 2 underwent kidney transplantation, 7 did not match the inclusion criteria later during observation. At T0 (49 patients) we observed 14 hs-cTnI positive patients vs. 4 standard c-TnI positive patients (28,5% vs 8,1%); at T1 (40 patients) 16 vs 3 (26.4% vs 7.5%); at T2 (34 pz) 9 vs 0 (26.4% vs 0%). During the study we recorded 10 cardiovascular events, 8 of which in patients that were hs-cTNI positive, leading to death in 3. Hs-cTnI levels were predictive of cardiovascular events at all times and predictive of cardiovascular mortality at T0 and T1 (p < 0.001). In a multivariate analysis, a history of coronary artery disease (CAD) was an independent variable of high hs-cTnI levels at T0 (p < 0.04) and T1 (p < 0.03).

CONCLUSIONS

Our study shows that a novel sensitive assay detects more asymptomatic HD patients compared to previously used methods, being at the same time predictive of cardiovascular mortality and morbidity. The only independent variable of high hs-cTnI concentrations was a positive history of cardiovascular disease, suggesting a possible role of hs-cTnI in identifying a high-risk subset of patients.

Left Atrial Remodeling Assessed by Cardiac MRI after Conversion from Conventional Hemodialysis to In-Centre Nocturnal Hemodialysis

BACKGROUND

Left atrial (LA) volume is a well-established cardiovascular prognosticator in patients with end-stage renal disease. Although dialysis intensification is associated with left ventricular mass regression, there are limited data regarding LA remodeling. Using cardiac magnetic resonance imaging (CMR), we examined changes in LA size and function relative to ventricular remodeling and cardiac biomarkers after dialysis intensification.

METHODS

In this prospective 2-centre cohort study, 37 patients receiving conventional hemodialysis (CHD, 4 h/session, 3×/week) were converted to in-centre nocturnal hemodialysis (INHD 7-8 h/session, 3×/week); 30 patients remained on CHD. CMR and biomarkers were performed at baseline and repeated at 52 weeks.

RESULTS

After 52 weeks, there were no significant changes in the LA volumes or LA ejection fraction (EF) within either the CHD or INHD group, and no significant differences between the two groups. Correlations existed between changes in LA and LV end-diastolic volume index (EDVi, Spearman's r = 0.69, p < 0.001), LA and LV end-systolic volume index (ESVi, r = 0.44, p = 0.001), LAEF and LVEF (r = 0.28, p = 0.04), LA and RV EDVi (r = 0.51, p < 0.001), LA and RV ESVi (r = 0.29, p = 0.039), and LA ESVi and LV mass index (r = 0.31, p = 0.02). At baseline, indexed LA volumes positively correlated with NT-proBNP, whereas LAEF negatively correlated with NT-proBNP and Troponin I. After 52 weeks, changes in biomarker levels did not correlate with changes in LA volume or EF.

CONCLUSION

There was no significant change in LA size or systolic function after conversion to INHD. The significant correlations between LA and ventricular remodeling and cardiac biomarkers suggest common underlying pathophysiologic mechanisms.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00718848.

Characterizing Cardiac Involvement in Chronic Kidney Disease Using CMR-a Systematic Review

PURPOSE OF REVIEW

The aim of the review was to identify and describe recent advances (over the last 3 years) in cardiac magnetic resonance (CMR) imaging in patients with chronic kidney disease (CKD). We conducted a literature review in line with current guidelines.

RECENT FINDINGS

The authors identified 22 studies. Patients with CKD had left ventricular global and regional dysfunction and adverse remodeling. Stress testing with CMR revealed a reduced stress-response in CKD patients. Native T1 relaxation times (as a surrogate markers of fibrosis) are elevated in CKD patients, proportional to disease duration. Patients with CKD have reduced strain magnitudes and reduced aortic distensibility.

SUMMARY

CMR has diagnostic utility to identify and characterize cardiac involvement in this patient group. A number of papers have described novel findings over the last 3 years, suggesting that CMR has potential to become more widely used in studies in this patient group.

Modern peptide biomarkers and echocardiography in cardiac healthy haemodialysis patients

BACKGROUND

In this prospective study, we aimed to assess the haemodynamic changes before and after haemodialysis (HD) in cardiac healthy subjects on chronic HD by imaging methods and endocrine markers of fluid balance.

METHODS

Mid-regional pro-atrial natriuretic peptide (MR-proANP), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), vasopressin (AVP) and copeptin (CT-proAVP), metanephrines and normetanephrines, renin and aldosterone, standard transthoracic echocardiography and diameter of vena cava inferior (VCID) were performed in 20 patients with end stage renal disease (CKD5D) before and after HD and were stratified in residual excretion (RE, less or more 0.5 l) and ultrafiltration rate (UF, less or more 2 l).

RESULTS

Copeptin was significantly higher in patients before HD. Copeptin was inversely correlated with haemodialysis treatment adequacy (KT/v), RE and UF, but was not significantly influenced by age, gender and body mass index (BMI). MR-proANP was significantly reduced by haemodialysis by 27% and was inversely correlated with KT/v, but there was a significant influence by UF, RE, age, gender and BMI. NT-proBNP was significantly higher in patients before HD and was not influenced by RE and UF. Renin, aldosterone, metanephrines and normetanephrines did not demonstrate significant differences. Echocardiographic parameters and VCID were significantly correlated with RE, UF and copeptin.

CONCLUSION

Modern biomarkers will provide cardiovascular risk assessment, but elimination (UF), RE and other factors may influence the serum concentrations, e.g. in patients with renal impairment. The interpretation will be limited by altered reference ranges, and will be restricted to individual courses combined with clinical and echocardiographic data.