Background:
Increased blood pressure variability (BPV) is detrimental in the weeks to months after ischemic stroke, but it has not been adequately studied in the acute phase. We hypothesized that increased BPV in acute ischemic stroke (AIS) patients would be associated with worse outcome.
Methods:
We retrospectively reviewed inpatients at our hospital between 2010-2014 with an ICD-9 code of AIS; 213 were confirmed to have AIS by a vascular neurologist. A modified Rankin Score (mRS) after discharge was available in 148/213, at a mean of 86 ± 60 days. In 45/213 the discharge mRS was either 0 or 6, in which case they were included in the final analysis. BPV was measured as the standard deviation (SD) of each patient’s systolic blood pressure readings during the first 24 hours and 5 days of hospitalization (9,844 total readings), or until discharge if discharged in <5 days (Figure 1). The SBP SD was further divided in quartiles. A multivariate ordinal logistic regression with the outcome of mRS, the primary predictor of quartiles of SBP SD, and baseline NIH stroke scale (NIHSS) to control for initial stroke severity.
Results:
Mean±SD age was 64.2 ± 16.3 years, NIHSS was 12.6 ± 7.9, and mRS was 2.7 ± 2.1. The mean SBP SDs for the first 24 hours and 5 days were 12.1 ± 6.2 mm Hg and 14.1 ± 4.9 mm Hg. In the ordinal logistic regression model, the quartiles of SBP SD for the first 24 hours and 5 days were positively associated with higher mRS (OR = 1.37, 95% CI 1.01 - 1.74, p = 0.009; OR = 1.30, 95% CI 1.03 - 1.63, p = 0.028). This effect became even more pronounced in patients with the highest quartile of variability (OR = 2.76, 95% CI 1.29 - 5.88, p = 0.009; OR = 2.10, 95% CI 1.01 - 4.36, p = 0.046).
Conclusion:
In our cohort of 193 patients with AIS, there was a significant association between increased systolic BPV and worse functional outcome, after controlling for initial stroke severity. This data suggests that increased BPV may have a harmful effect for AIS patients, which warrants a prospective observational study.
Association between Blood Pressure Variability and Functional Outcomes after Successful Mechanical Thrombectomy in Acute Ischemic Stroke
