Older Adults With Higher Blood Pressure Variability Exhibit Cerebrovascular Reactivity Deficits

BACKGROUND Elevated blood pressure (BP) variability is predictive of increased risk for stroke, cerebrovascular disease, and other vascular brain injuries, independent of traditionally studied average BP levels. However, no studies to date have evaluated whether BP variability is related to diminished cerebrovascular reactivity, which may represent an early marker of cerebrovascular dysfunction presaging vascular brain injury. METHODS The present study investigated BP variability and cerebrovascular reactivity in a sample of 41 community-dwelling older adults (mean age 69.6 [SD 8.7] years) without a history of dementia or stroke. Short-term BP variability was determined from BP measurements collected continuously during a 5-minute resting period followed by cerebrovascular reactivity during 5-minute hypocapnia and hypercapnia challenge induced by visually guided breathing conditions. Cerebrovascular reactivity was quantified as percent change in cerebral perfusion by pseudo-continuous arterial spin labeling (pCASL)-MRI per unit change in end-tidal CO2. RESULTS Elevated systolic BP variability was related to lower whole brain cerebrovascular reactivity during hypocapnia (ss = -0.43 [95% CI -0.73, -0.12]; P = 0.008; adjusted R-2 =.11) and hypercapnia (ss = -0.42 [95% CI -0.77, -0.06]; P = 0.02; adjusted R-2 = 0.19). CONCLUSIONS Findings add to prior work linking BP variability and cerebrovascular disease burden and suggest BP variability may also be related to prodromal markers of cerebrovascular dysfunction and disease, with potential therapeutic implications.

Automated summary

Elevated blood pressure variability is associated with decreased cerebrovascular reactivity, indicating potential early markers of cerebrovascular dysfunction and disease.