Blunted nocturnal blood pressure decrease and left-ventricular mass in hypertensive hemodialysis patients

Left-ventricular hypertrophy (LVH) represents a frequent complication in hemodialysis (HD) patients. Hypertension is a well-known risk factor of cardiac morbidity which is present in 2 of 3 patients: among them about 60% have a blunted nocturnal decrease of blood pressure (BP). Although some large studies on essential hypertensives have documented that non-dipper patients have a higher number of cardiac events and a higher left ventricle (LV) mass than dipper ones, conflicting results have been reported for dialysis patients. Therefore, the aim of our study was to assess differences in LV mass between dipper and non-dipper hypertensive HD patients. We studied 66 patients with 24-hour ambulatory BP monitoring performed on HD and on inter-HD day. They were classified as dipper when a decrease of at least 10% of nocturnal systolic blood pressure on the inter-HD day was present. Echocardiography and bioimpedance were performed. 29% of the patients were classified as dippers and 71% as non-dippers. The 48-hour systolic and diastolic BP were not significantly different between the two groups (SBP: dipper = 144 +/- 12.9 mm Hg, non-dipper = 149 +/- 17.8 mm Hg; DBP: dipper = 80 +/- 9.9 mm Hg, non-dipper = 81 +/- 10.6 mm Hg). LV mass index (LVMi) did not differ between the two groups (dipper = 143.1 +/- 40.7 g/m(2); non-dipper = 159.4 +/- 46.3 g/m(2)). No differences were reported between dipper and non-dipper patients regarding extracellular water distribution (ECW: 48.1 +/- 7.7 vs. 49.8 +/- 10.8%). SBP night/day ratio and 48-hour SBP were not correlated to LVMi. A strong correlation was reported between ECW% and LVMi (r = 0.53, p < 0.001). In conclusion, 2 of 3 hypertensive HD patients are non-dipper, and this condition does not seem to be associated with significant differences in 48-hour blood pressure and LV mass. Volume overload appears to be the main independent determinant of LVH in these patients.