Does Hypertension Affect Cerebral Blood-Flow Autoregulation?

Cerebral autoregulation, the intrinsic ability of the cerebral circulation to maintain a constant blood flow in the face of blood pressure changes, is a fast-acting mechanism. In hypertension, both lower and upper limits of cerebral blood-flow autoregulation are shifted toward higher pressures, predisposing patients with hypertension to cerebral hypoperfusion and, possibly, ischemia. Whether hypertension also affects the rate of the autoregulatory response is unknown. Understanding the dynamic response time of cerebral autoregulation not only is important for its clinical and therapeutic implications, but also is of interest from a physiologic perspective.

These authors compared rates of cerebral autoregulation in 21 patients treated for hyp…