P87 Cerebrovascular Reactivity During Cognitive Activation in Adults with Controlled Hypertension

Abstract

Hypertension, even when pharmaceutically controlled, may accelerate arterial stiffening and impair changes in blood flow necessary to support neural activity (neurovascular coupling [NVC]). Optimal NVC requires continuous, non-pulsatile flow, which is partially determined by extra- and intra-cranial vessel function.

Purpose

Examine extra- and intra-cranial hemodynamics during cognitive activity in adults with well-controlled hypertension and without hypertension.

Methods

30 middle-aged, medicated hypertensive and 30 age-, sex-, and Body Mass Index (BMI)-matched non-hypertensive adults (56 ± 6 yrs, BMI 28.2 ± 2.9 kg/m²; 32 men) underwent cerebrovascular measures at rest and during a Stroop task. Applanation tonometry and ultrasound were used to assess aortic and carotid (single-point) Pulse Wave Velocity (PWV), respectively. Ultrasound and Doppler were used to measure carotid and Middle Cerebral Artery (MCA) blood velocity pulsatility. Near-infrared spectroscopy was used to measure prefrontal oxygenation (tissue saturation index; TSI). Accuracy and reaction times were computed to assess cognitive performance.

Results

Stroop performance was similar between groups (p > 0.01). Aortic and carotid PWV increased, carotid pulsatility decreased (p0.01; Table 1). Reductions in CCA pulsatility during the Stroop were associated with increases in cortical TSI in the combined sample (r = 0.27), suggesting extracranial hemodynamics may play a role in optimizing intracranial NVC.

Conclusions

Our findings indicate that middle-age adults with medically-controlled hypertension display similar intra- and extra-cranial cerebrovascular reactivity to adults without hypertension. Additionally, adults with and without hypertension may utilize reductions in extracranial pulsatility during NVC to minimize intracranial pulsatility and improve downstream cerebral oxygenation.