Blood pressure variability at rest and during pressor challenges in patients with acute ischemic stroke.

Abstract

Patients with acute ischemic stroke (AIS) have elevated blood pressure (BP) variability (BPV) and reduced baroreflex sensitivity (BRS) at rest for several days after initial stroke symptoms. We aimed to assess BPV and BRS in AIS patients during pressor challenge maneuvers in the acute and subacute phases of stroke. Pressor challenge maneuvers simulate day-to-day activities and can predict the quality of life. Continuous beat-to-beat BP and ECG in 15 AIS patients (mean age 69 ± 7.5 years) and 15 healthy controls (57 ± 16 years) were recorded at rest and during a 5-min rapid head positioning (RHP) paradigm. Patients were assessed within 24 h (acute phase) and 7 days (subacute phase) of stroke onset. Low frequency (LF) SBP power (measure of BPV), LF-α, and combined α-index (measure of BRS) were calculated from the recordings. In the acute phase, at rest, LF-SBP power was higher ( P = 0.024) and α-index was lower ( P = 0.006) in AIS patients than in healthy controls. There was no change in LF-SBP during RHP in the patients but in healthy controls, it increased significantly ( P = 0.018). In the subacute phase, at rest, the alpha-index increased ( P = 0.037) and LF-SBP decreased ( P = 0.029) significantly in the AIS patients, however, there was still no rise in the LF-SBP power during RHP ( P = 0.240). AIS patients have a high resting BPV. High resting BPV may be responsible for blunted BPV responses during pressor challenge maneuvers such as RHP, suggesting ongoing autonomic dysfunction and compromised quality of life.