Differential Effects of Aliskiren/Amlodipine Combination and High-Dose Amlodipine Monotherapy on Endothelial Function in Elderly Hypertensive Patients

BACKGROUND: The aim of this study was to compare the effects of direct renin inhibitor, aliskiren, and amlodipine combination therapy with those of high-dose amlodipine monotherapy on endothelial function in elderly hypertensive patients. METHODS: Participants included 105 patients (mean age 77 years) who had receive 5mg amlodipine for 4 weeks. Patients were allocated to the aliskiren/amlodipine group (AL/AM) or the high-dose amlodipine (AM) group. The AL/AM group received 150mg aliskiren in addition to 5mg amlodipine for 8 weeks; then the dose of aliskiren was doubled to 300mg for another 8 weeks. The AM group received 10mg amlodipine for 16 weeks. Of the 105 patients, 87 who underwent measurements of brachial flow-mediated vasodilation (FMD) and nitroglycerin-mediated vasodilation (NMD) before and after the study were included in the analysis. RESULTS: Blood pressure-lowering effects were similar in the 2 groups. Plasma renin activity significantly decreased in the AL/AM group (P < 0.001) but increased in the AM group (P < 0.001). Improvement of FMD was found in the AL/AM group (2.6% to 3.7%, P = 0.001) but not in the AM group, while NMD did not change in either group. The changes in 24-hour systolic blood pressure (r = -0.60, P < 0.001) and diastolic blood pressure (r = -0.46, P = 0.004) were significantly correlated with improvement of FMD in the AL/AM group but not in the AM group. CONCLUSION: Addition of aliskiren improved endothelial function in elderly hypertensive patients treated with amlodipine. CLINICAL TRIAL REGISTRY NUMBER: UMIN000010163.