Maintenance of blood pressure (BP) significantly reduces adverse clinical outcomes after stroke, according to study findings published in the journal BMC Neurology.
Currently, there is no recommended BP level range in patients who have experienced an acute ischemic stroke. Although elevations of BP in the acute phase post stroke is common as a compensatory mechanism to increase blood flow to the ischemic areas, BP management continues to be an unsettled matter.
For the study, researchers sought to investigate admission BP levels in those with acute ischemic stroke to assess optimal BP values for best clinical outcomes.
The researchers conducted a retrospective observational study using data from the stroke center of Jiangsu Province Hospital of Chinese Medicine from December 2020 to July 2021. Inclusion criteria consisted of those who experienced an acute ischemic stroke and seen within 72 hours of symptom onset, ischemic lesions on imaging, and have had serial BP measurements every 4 hours during the first 24 hours and every 8 hours thereafter.
Individuals who have had terminal diseases, or treated with reperfusion therapy were excluded from the study. Potential risk factors for stroke, such as age, hypertension, diabetes mellitus, dyslipidemia, coronary artery disease, and smoking were included as covariates.
Primary outcome was severity of neurologic deficit, measured 3 months after onset of symptoms by using the modified Rankin Scale (mRS) (0-2 considered favorable; ≥3 considered poor outcome).
A total of 649 patients were include in the study. Out of 649 patients, 92 (14.18%) were considered to have poor outcomes and 557 (85.82%) had favorable outcomes.
A “U-curve pattern” was found in relationship to systolic BP (SBP) and functional prognosis, with extremes of BP associated with poorer outcomes. Diastolic blood pressure was not statistically significant for prognosis. Patients with mean SBP that was above 150 mmHg and below 135 mmHg had a higher mRS score and morality rate when compared with those with mean SBP between 135 mmHg and 150 mmHg.
Threshold analysis using linear regression found that when BP was <138 mmHg, odds of outcomes negatively correlated with BP (Odds ratio [OR], 0.936; 95% CI, 0.882-0.992; P = .0258). Conversely, when BP >135 mmHg, incidence of poor outcomes increased with increasing SBP (OR, 1.036; 95% CI, 1.008-1.066; P = .0125).
Piecewise linear regression according to best range of fitting results found optimal BP range to be 135-150 mmHg. Lower and higher pressures were associated with functional outcomes (BP <135 mmHg; OR, 1.9; 95% Cl, 1.11-3.36; P =.021; BP >150 mmHg; OR, 1.95; 95% CI, 1.12-3.37; P =.017).
Likewise, adjusted regression models for use of antihypertensive therapy found a significant increase of probability of poor functional outcomes in patients with SBP <135 mmHg or >145 mmHg, confirming the U-shaped pattern.
A study limitation included sampling error, as this was a single study conducted on a relatively small cohort.
The researchers concluded, “The result of the present study indicates that maintenance of mean BP between 135 mmHg and 150 mmHg in AIS [acute ischemic stroke] patients during hospitalization is associated with promising short- or long-term clinical outcomes.”
Hu M, Zhu Y, Chen Z, et al. Relationship between mean blood pressure during hospitalization and clinical outcome after acute ischemic stroke. BMC Neurol. 2023;23(1):156. Published online April 20, 2023. doi:10.1186/s12883-023-03209-3