Echocardiography in patients with chronic kidney diseases

The significance of volume overload in the development of pulmonary arterial hypertension in continuous ambulatory peritoneal dialysis patients

INTRODUCTION

The underlying pathophysiology of pulmonary arterial hypertension (PAH) is multifactorial; however, the significance of chronic volume overload and its subsequent effects on cardiac function must be studied thoroughly. The main objective of this study was to determine the predictive parameters of PAH in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) using transthoracic echocardiography (TTE) and bioimpedance analysis (BIA).

METHODS

In this cross-sectional study, 43 eligible CAPD patients were chosen. The patients were examined by TTE and BIA before the morning dialysis session, and baseline patient characteristics, echocardiography, and BIA parameters were recorded.

RESULTS

Sixteen (37.2%) patients were diagnosed with PAH. Patients with PAH had significantly greater left atrial diameter (LAD), left ventricular mass index (LVMI), and higher grades of diastolic dysfunction (DDF). Systolic pulmonary artery pressure (sPAP) correlated with LAD (p < 0.001, r = 0.566), interventricular septal diameter (IVSD) (p = 0.004, r = 0.425), LVMI (p = 0.030, r = 0.323), and extracellular water/total body water (ECW/TBW) ratio (p = 0.002, r = 0.458).

CONCLUSION

Two volume status-related parameters including ECW/TBW ratio and inferior vena cava (IVC) expiratory diameter, and cardiac-related TTE findings such as LAD and DDF were predictors of sPAP in CAPD patients.

3D Echocardiography - A Useful Method for Cardiovascular Risk Assessment in End-Stage Renal Disease Patients

Patients with chronic kidney disease (CKD) have an increased risk of premature mortality, mainly due to cardiovascular causes. The association between hemodialysis and accelerated atherosclerosis has long been described. The ankle-brachial index (ABI) is a surrogate marker of atherosclerosis and recent studies indicate its utility as a predictor of future cardiovascular disease and all-cause mortality. The clinical implications of ABI cut-points are not well defined in patients with CKD. Echocardiography is the most widely used imaging method for cardiac evaluation. Structural and functional myocardial abnormalities are common in patients with CKD due to pressure and volume overload as well as non-hemodynamic factors associated with CKD. Our study aimed to identify markers of subclinical cardiovascular risk assessed using ABI and 2D and 3D echocardiographic parameters evaluating left ventricular (LV) structure and function in patients with end-stage renal disease (ESRD) (patients undergoing dialysis), patients after kidney transplantation and non-ESRD patients (control). In ESRD, particularly in hemodialysis patients, changes in cardiac structure, rather than function, seems to be more pronounced. 3D echocardiography appears to be more sensitive than 2D echocardiography in the assessment of myocardial structure and function in CKD patients. Particularly 3D derived end-diastolic volume and 3D derived LV mass indexed for body surface appears to deteriorate in dialyzed and transplanted patients. In 2D echocardiography, myocardial mass represented by left ventricular mass/body surface area index (LVMI) appears to be a more sensitive marker of cardiac structural changes, compared to relative wall thickness (RWT), left ventricle and diastolic diameter index (LVEDDI) and left atrial volume index (LAVI). We observed a generally favorable impact of kidney transplantation on cardiac structure and function; however, the differences were non-significant. The improvement seems to be more pronounced in cardiac function parameters, peak early diastolic velocity/average peak early diastolic velocity of mitral valve annulus (E/e´), 3D left ventricle ejection fraction (LV EF) and global longitudinal strain (GLS). We conclude that ABI is not an appropriate screening test to determine the cardiovascular risk in patients with ESRD.

Coronary microvascular dysfunction is associated with degree of anaemia in end-stage renal disease

BACKGROUND

Coronary microvascular dysfunction (CMD) is common in end-stage renal disease (ESRD) and is an adverse prognostic marker. Coronary flow velocity reserve (CFVR) is a measure of coronary microvascular function and can be assessed using Doppler echocardiography. Reduced CFVR in ESRD has been attributed to factors such as diabetes, hypertension and left ventricular hypertrophy. The contributory role of other mediators important in the development of cardiovascular disease in ESRD has not been studied. The aim of this study was to examine the prevalence of CMD in a cohort of kidney transplant candidates and to look for associations of CMD with markers of anaemia, bone mineral metabolism and chronic inflammation.

METHODS

Twenty-two kidney transplant candidates with ESRD were studied with myocardial contrast echocardiography, Doppler CFVR assessment and serum multiplex immunoassay analysis. Individuals with diabetes, uncontrolled hypertension or ischaemic heart disease were excluded.

RESULTS

7/22 subjects had CMD (defined as CFVR < 2). Demographic, laboratory and echocardiographic parameters and serum biomarkers were similar between subjects with and without CMD. Subjects with CMD had significantly lower haemoglobin than subjects without CMD (102 g/L ± 12 vs. 117 g/L ± 11, p = 0.008). There was a positive correlation between haemoglobin and CFVR (r = 0.7, p = 0.001). Similar results were seen for haematocrit. In regression analyses, haemoglobin was an independent predictor of CFVR (β = 0.041 95% confidence interval 0.012-0.071, p = 0.009) and of CFVR < 2 (odds ratio 0.85 95% confidence interval 0.74-0.98, p = 0.022).

CONCLUSIONS

Among kidney transplant candidates with ESRD, there is a high prevalence of CMD, despite the absence of traditional risk factors. Anaemia may be a potential driver of microvascular dysfunction in this population and requires further investigation.

Hemodialysis vascular access affects heart function and outcomes: Tips for choosing the right access for the individual patient

Chronic kidney disease is associated with increased cardiovascular morbidity and mortality. A well-functioning vascular access is associated with improved survival and among the available types of vascular access the arterio-venous (AV) fistula is the one associated with the best outcomes. However, AV access may affect heart function and, in some patients, could worsen the clinical status. This review article focuses on the specific cardiovascular hemodynamics of dialysis patients and how it is affected by the AV access; the effects of an excessive increase in AV access flow, leading to high-output heart failure; congestive heart failure in CKD patients and the contraindications to AV access; pulmonary hypertension. In severe heart failure, peritoneal dialysis (PD) might be the better choice for cardiac health, but if contraindicated suggestions for vascular access selection are provided based on the individual clinical presentation. Management of the AV access after kidney transplantation is also addressed, considering the cardiovascular benefit of AV access ligation compared to the advantage of having a functioning AVF as backup in case of allograft failure. In PD patients, who need to switch to hemodialysis, vascular access should be created timely. The influence of AV access in patients undergoing cardiac surgery for valvular or ischemic heart disease is also addressed. Cardiovascular implantable electronic devices are increasingly implanted in dialysis patients, but when doing so, the type and location of vascular access should be considered.