Time-dependent shift of the relationship between systolic blood pressure and clinical outcome in acute lacunar stroke

Background and aims This study explores the relationship between systolic blood pressure during the acute period of stroke and poor functional outcome in patients with lacunar stroke, emphasizing a possible time-dependent nature of the relationship. Methods Based on multicenter stroke registry data, patients with acute lacunar stroke were identified, and systolic blood pressure levels at eight time points (1, 2, 4, 8, 16, 24, 48, and 72 h) after stroke onset were extracted at the 15 participating centers in South Korea. Poor functional outcome was defined as a three-month modified Rankin Scale score of 2-6. Non-linear restricted cubic spline and linear models were used for assessing the relationship at each time point. Results A total of 97,349 systolic blood pressure measurements of 3,042 patients were analyzed. At 1 h and 4 h after stroke onset, the relationship between systolic blood pressure and poor outcome showed a non-linear association. The nadir was 155 mmHg at 1 h and 124 mmHg at 4 h. After this time period, a higher systolic blood pressure was associated with a poorer outcome. This linear relationship weakened over time after 12 h (coefficient values of the adjusted linear models: 0.0081 at 8 h, 0.0105 at 12 h, 0.0102 at 24 h, 0.0082 at 48 h, 0.0054 at 72 h). Conclusions Based on our cohort of large number of lacunar stroke patients, our findings suggest that systolic blood pressure levels may follow a time-dependent course in relation to prediction of outcome at three months. The findings may be valuable for hypothesis generation in association with clinical trial development for blood pressure control in acute stroke patients.