Are day-to-day blood pressure swings after an ischemic stroke linked to recurrence?

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The study asked whether day-to-day blood pressure variability during the subacute stage of acute ischemic stroke predicts long-term stroke recurrence. Researchers analyzed 7,665 patients hospitalized for a first-ever ischemic stroke at seven stroke centers in Fukuoka, Japan, from June 2007 to November 2018; their mean age was 72.9±13.1 years, and 42.4% were women.

Blood pressure was measured daily during the subacute stage, 4–10 days after onset. The researchers calculated mean blood pressure and its coefficient of variation (CV), dividing patients into four groups according to quartiles of these measures. Patients were followed prospectively for recurrent stroke or death from any cause. Cumulative event rates were calculated using the Kaplan–Meier method. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals after adjustment for potential confounders and mean blood pressure. A Fine–Gray model also accounted for death as a competing risk.

Over a mean follow-up of 3.9±3.2 years, recurrent stroke and all-cause death occurred at rates of 3.9 and 9.9 per 100 patient-years, respectively. Cumulative rates of both recurrent stroke and all-cause death increased as the CVs of systolic and diastolic blood pressure increased. After adjustment for multiple confounders and mean blood pressure, the highest versus lowest quartile of systolic blood pressure CV was associated with a higher risk of recurrent stroke: hazard ratio 1.26 (95% CI 1.05–1.50). The association also held for nonfatal recurrent strokes (1.26, 95% CI 1.05–1.51) and when death was treated as a competing risk (1.21, 95% CI 1.02–1.45). Similar associations were observed for diastolic blood pressure CV. The researchers concluded that day-to-day blood pressure variability in the subacute stage of acute ischemic stroke was associated with increased long-term stroke recurrence risk.