Background: Left ventricular hypertrophy is the main manifestation of uraemic cardiomyopathy and predicts both cardiovascular events and death independently of conventional risk factors. Diastolic dysfunction is often associated with left ventricular hypertrophy, and accounts for up to 30% of heart failure. The aim of this study was to estimate the impact and the prevalence of left ventricular hypertrophy, its geometric models and diastolic dysfunction on haemodialysis patients, as well as the relationship with cardiac troponin, a specific marker for myocardial damage.
Methods: We enrolled in the study 31 patients (26 on haemodialysis, 5 on peritoneal dialysis) and 31 normal healthy subjects as the control group. Echocardiographic measurements were carried out according to the recommendations of the American Society of Echocardiography. Left ventricular mass was calculated according to the Devereux formula and indexed to height 2.7 We carried out Doppler echocardiography to study the diastolic function by measurements of isovolumic relaxation period (IVRT), E-wave deceleration time (DTE) and E/A ratio. We measured cardiac troponin using a third generation electrochemiluminescence immunoassay. We did the statistical analysis with the t test for comparison among groups, and we established correlations using the Pearson and Spearman correlation test. We considered values of p<0.05 to be statistically significant.
Results: Eccentric hypertrophy was the most frequent pattern (n=17; 55%), followed by normal cardiac geometry (n=7; 23%) and concentric hypertrophy (n=5; 16%). Only a minority of patients (n=2; 6%) showed concentric remodelling. Systolic dysfunction was present in 3 patients (EF<50%). Diastolic dysfunction was present in 24 out of 31 HD patients, that had abnormal relaxation pattern, characterised by prolonged IVRT, prolonged DTE and E/A ratio <1. Only one patient had restrictive filling pattern with reduced DTE and E/A ratio >2. Fourteen patients (45%) had E/A ratio < or =0.5, 10 patients (32%) had E/A ratio >0.5<1 and 7 patients (13%) had E/A ratio > or =1. DTE was prolonged in 14 patients (45%) and IVRT was prolonged in 6 patients (19%). The patients with E/A ratio < or =0.5 (n=14; 45%) suffered major hypotensive episodes during dialytic sessions compared to patients with E/A ratio >0.5, we found this difference to be statistically significant (p < 0.01). We observed the E/A ratio to be negatively correlated with age (r = -0.41; p=0.02) whereas DTE was positively correlated with posterior wall thickness (r =0.36; p= 0.05) and interventricular septum thickness (r =0.45; p=0.01). Cardiac troponin was positively correlated with age (r =0.50; p=0.00), left ventricular mass (r =0.41; p=0.02), posterior wall thickness (r =0.41; p=0.02) and interventricular septum thickness (r =0.39; p=0.03) but not with diastolic dysfunction parameters. Serum cardiac troponin was elevated (> or =0.10 micro g/L) in 12 patients (38.7%) and was associated with eccentric hypertrophy in all the cases. We detected no significant differences among groups with normal left ventricular geometry and left ventricular hypertrophy in the duration of the dialytic treatment, but we noted a statistically significant difference in relationship to age (p=0.03).
Conclusions: Left ventricular hypertrophy is associated with diastolic dysfunction, both cause of hypotensive episodes during dialytic treatments and heart failure in patients with normal systolic function. The non invasive assessment of left ventricular diastolic function would represent an important advancement in the diagnosis and prevention of heart failure in haemodialysis patients.