Uremic cardiomyopathy: An inadequate left ventricular hypertrophy

Abstract

Echocardiographic study of the left ventricle was performed in 57 selected, normotensive hemodialysis patients in comparison to 40 healthy controls matched for sex, age and blood pressure. The statistically significant abnormalities in uremic patients were an enlargement of the left ventricular end-diastolic diameter (LVEDiD) (5.58 ± 0.60 vs. 5.05 ± 0.5 cm; P<0.001) and an increase in the left ventricular radius to posterior wall-thickness ratio (r/Th) 3.65 ± 0.68 vs. 3.27 ± 0.44; P<0.001). Enlargement of the ventricle was related to anemia (P<0.001) and the hemodynamic effect of arteriovenous fistula. Ventricular radius to wall thickness ratio was inversely related to systolic arterial pressure in controls (P<0.001) and patients (P<0.01) with a significant upward shift of the regression in dialysis patients (P<0.001). In dialysis patients, the left ventricular posterior wall thickness (LVPWT) was inversely correlated to serum parathormone (PTH) level ((P<0.001), and r/Th ratio was positively correlated to serum PTH (P<0.001). Bone biopsy was performed in 28 patients. Histomorphometric indexes of osteitis fibrosa were in dialysis patients, correlated to echocardiographic abnormalities; osteoclasts number was inversely correlated to LVPWT (P<0.001) and positively related to r/Th ratio (P<0.001). Osteoclastic resorption surfaces and LVPWT were inversely correlated (P<0.001), while a positive correlation between r/Th ratio and osteoclastic resorption surfaces was observed (P<0.001). Osteoblastic surfaces and tetracycline double-labeled surfaces were also correlated to LVPWT (P<0.001) and r/Th ratio (P<0.001). During longitudinal survey, a decrease in LVPWT with an increase in r/Th ratio was observed only in dialysis patients with bone histologic signs of active secondary hyperparathyroidism. Our findings suggest that inadequate left-ventricular hypertrophy is, in dialysis patients, associated with the severity and progression of secondary hyperparathyroidism. The hemodynamic significance of these abnormalities is not clear, since functional indices of left ventricular function remain within the normal range.