Blood pressure reduction in acute ischemic stroke according to time to treatment: a subgroup analysis of the China Antihypertensive Trial in Acute Ischemic Stroke trial

Objective: The optimal time to initiate antihypertensive therapy among patients with acute ischemic stroke remains uncertain. We tested the effects of blood pressure reduction among patients with acute ischemic stroke according to time from onset to initiation of antihypertensive treatment. Methods: We randomly assigned 4071 acute ischemic stroke patients with elevated SBP to receive antihypertensive treatment or to discontinue all antihypertensive medications during hospitalization. The primary outcome was a combination of death and major disability, and secondary outcomes included the modified Rankin score, recurrent stroke, vascular disease events, and all-cause mortality. Results: At 24 h after randomization, the differences in SBP reductions were 8.7, 9.5, and 9.6 mmHg between the antihypertensive treatment and control groups among patients receiving treatment within less than 12, 12-23, and 24-48 h after stroke onset, respectively (P< 0.001 in all subgroups). At day 14 or hospital discharge, the primary and secondary outcomes were not significantly different between the treatment and control groups in all subgroups. At the 3-month follow-up, death or major disability [odds ratio (OR) 0.73; 95% confidence interval (CI) 0.55-0.96; P = 0.03], recurrent stroke (OR 0.25; 95% CI 0.08-0.74; P = 0.01), and vascular events (OR 0.41; 95% CI 0.18-0.95; P = 0.04) were significantly reduced in the antihypertensive treatment group only among participants who received treatment between 24 and 48 h. Conclusion: Blood pressure reduction might reduce 3-month death and major disability and recurrent stroke among patients with acute ischemic stroke who receive antihypertensive treatment between 24 and 48 h after stroke onset.