Effects of different classes of antihypertensive drugs on cerebral hemodynamics in elderly hypertensive patients

Background: This study was designed to estimate the effect of different classes of antihypertensive drugs on cerebral hemodynamics in elderly stroke-free, nondiabetic hypertensive patients by applying frequency-domain techniques. Methods: A total of 60 hypertensive patients divided into treatment groups of 15 unmedicated (HT), 15 nifedepine sustained release form (CCB), 15 atenolol (BB), and 15 valsartan (AIIA), and 15 age-matched healthy volunteers (CON) were studied prospectively. Variability of arterial blood pressure (ABP) and middle cerebral artery flow velocity (MCAFV) detected by transcranial Doppler sonography were diffracted into very-low frequency (VLF, 0.016 to 0.04 Hz), low frequency (LF, 0.04 to 0.15 Hz), and high frequency (HF, 0.15 to 0.4 Hz). Cerebral hemodynamics was quantified by the ABP-MCAFV transfer function. Results: The ABP and MCAFV were statistically different between CON and HT groups, but not significantly different among CON, CCB, BB, and AIIA groups. The LF phase and HF magnitude in the HT, CCB, and BB groups were significantly attenuated than in those of the CON group, but not statistically different between the AIIA and CON groups. There was no statistical difference in VLF and LF transfer magnitude among the five groups. Conclusions: Although cerebral vasomotor reserve and cerebral blood flow are impaired in unmedicated hypertensive patients, the cerebral autoregulatory response was preserved both in controlled and uncontrolled hypertension. Nifedipine, atenolol, and valsartan are all effective as monotherapy to control ABP and restore cerebral blood flow. Valsartan has the effect to normalize the changes in cerebral vasomotor reserve to a level similar as in age-matched healthy subjects.