Benefits of the angiotensin II receptor antagonist olmesartan in controlling hypertension and cerebral hemodynamics after stroke

Abstract

The purpose of this study was to assess the relative benefits of angiotensin II receptor blockers (ARBs) and calcium channel blockers (CCBs) on cerebral hemodynamics and rehabilitation outcome in hypertensive stroke patients. We randomly assigned 35 patients to either the olmesartan (n=18) or amlodipine (n=17) treatment groups for 8 weeks. Changes in cerebral blood flow (CBF) and cerebrovascular reserve capacity (CRC) were quantified using xenon-CT and rehabilitation parameters were also measured. Over 24 h, olmesartan and amlodipine both reduced blood pressure (BP) to similar levels (systolic BP, -16.1+/-2.7 mm Hg vs. -15.7+/-3.1; diastolic BP, -9.2+/-2.9 vs. -8.6+/-3.3 mm Hg, respectively). In olmesartan-treated patients, CBF significantly increased in the affected and unaffected hemispheres, and CRC increased significantly in the affected hemisphere. No increases in CBF and CRC were observed in amlodipine-treated patients. Patients treated with olmesartan showed effective rates of improvement in hand (30.0%), upper extremities (40.0%) and lower extremities (100.0%), measured by Brunnstrom stage; these improvements were significantly different from those in amlodipine-treated patients for the total (P<0.02) and lower extremity (P<0.05) scores. There were no significant differences in Barthel indices and Mini-Mental State Examination (MMSE) scores. Olmesartan, but not amlodipine, had beneficial effects on CBF, CRC and rehabilitation outcomes in hypertensive stroke patients, by a mechanism independent of BP reduction and possibly by normalizing CBF autoregulation. Our results suggest that olmesartan may improve cerebral circulation and rehabilitation in hypertensive stroke patients in whom CBF autoregulation is impaired.