Updated: Oct 2
Hemorrhagic transformation after successful endovascular therapy (EVT) in acute ischemic stroke due to large vessel occlusion has been shown to be associated with worsened clinical outcomes. Therefore, opportunities to further optimize clinical outcomes may include a lower blood pressure target. Some observational and retrospective studies found that lower systolic BP in the hours after thrombectomy is associated with better clinical outcomes 
After a stroke, the brain's natural ability to regulate blood flow (autoregulation) is compromised. This means that cerebral blood flow becomes pressure dependent and may decrease with lowering BP, leading to infarct expansion and worse outcomes. Both hypotensive and hypertensive episodes can lead to worse clinical outcomes. Therefore, major health organizations like the American Heart Association and the European Stroke Organization advise keeping BP below 180/105 mm Hg and not letting the systolic BP drop below 130 mm Hg.
Does early intensive blood pressure management (SBP 120-139 mmHg) improve outcomes after successful endovascular thrombectomy in acute ischemic stroke?
Two previous studies, BP-TARGET and ENCHANTED2/MT, aimed to see if strictly controlling blood pressure (BP) after stroke treatments could improve patient outcomes. Both studies set aggressive targets for lowering systolic BP: below 130 mm Hg for 24 hours in BP-TARGET and below 120 mm Hg for 72 hours in ENCHANTED2/MT. However, neither study found a reduction in hemorrhagic transformation. In the ENCHANTED2/MT study, patients with stricter BP control experienced more low BP episodes (46% vs. 12% in the standard treatment group). This study was even stopped early because the stricter BP control group had worse recovery outcomes [1-2].
The OPTIMAL-BP study, conducted at 19 centers in South Korea, aimed to determine the benefits of strict blood pressure (BP) control after stroke treatments. Though it intended to enroll 668 participants, it was halted early with 306 enrollments due to concerns about the strict BP control's risks. Patients were categorized shortly after successful stroke treatment into two groups: one with intensive control targeting a systolic BP (SBP) below 140 mm Hg and the other with conventional control aiming for an SBP between 140-180 mm Hg. The objective was to achieve these BP levels within an hour and sustain them for 24 hours. In the intensive group, 83% reached their BP target. Interestingly, many in the conventional group also had BPs below 140 mm Hg, with only 42% maintaining their 140-180 mm Hg target, possibly because BP tends to decrease after successful stroke treatment.
The results indicated that 39% of the intensive control group achieved functional independence recovered compared to 54% in the conventional group. Episodes of low BP were more frequent in the intensive group (30% vs. 17%). Despite the intensive group having lower BPs, both groups experienced similar rates of intracerebral hemorrhage (9.0% in the intensive group and 8.1% in the conventional group, P = .82) .
The BEST-II trial, conducted at three US centers with 120 patients, aimed to see if reducing blood pressure post-stroke could lessen brain damage and aid recovery after 90 days. Patients were grouped based on target blood pressures: below 140 mm Hg, below 160 mm Hg, or up to 180 mm Hg, maintained for 24 hours. The study suggested a low likelihood of success for stricter blood pressure controls in a larger trial. Specifically, there was a 25% chance for the below 140 mm Hg group and 14% for the below 160 mm Hg group. BEST-II showcased the efficiency of such preliminary studies in gauging potential benefits with fewer participants than larger studies .
A cautious strategy for blood pressure management post-stroke involves permitting cerebral autoregulation, to be established. This means allowing the body to naturally adjust blood flow in response to the stroke and subsequent treatment. Active intervention to control blood pressure should only be considered when there is a substantial risk that very high blood pressure levels could significantly increase the likelihood of intracerebral hemorrhage. We follow the American Heart Association and the European Stroke Organization guidelines and maintain systolic blood pressure <180 mm Hg and diastolic blood pressure below 105 mm Hg. We try to avoid drops in the systolic blood pressure below 130-140 mm Hg.
de Havenon A, Petersen N, Sultan-Qurraie A, et al. Blood pressure management before, during, and after endovascular thrombectomy for acute ischemic stroke. Semin Neurol. 2021;41(1):46-53. [PubMed]
Mazighi M, Richard S, Lapergue B, et al; BP-TARGET investigators. Safety and efficacy of intensive blood pressure lowering after successful endovascular therapy in acute ischaemic stroke (BP-TARGET): a multicentre, open-label, randomised controlled trial. Lancet Neurol. 2021;20(4):265-274.[PubMed}
Yang P, Song L, Zhang Y, et al. ENCHANTED2/MT Investigators. Intensive blood pressure control after endovascular thrombectomy for acute ischaemic stroke (ENCHANTED2/MT): a multicentre, open-label, blinded-endpoint, randomised controlled trial. Lancet. 2022;400(10363):1585-1596. [PubMed]
Nam HS, Kim YD, Heo JN, et al; OPTIMAL-BP Trial Investigators. Intensive vs conventional blood pressure lowering after endovascular thrombectomy in acute ischemic stroke: the OPTIMAL-BP randomized clinical trial. JAMA. Published September 5, 2023. doi:10.1001/jama.2023.14590
Mistry EA, Hart KW, Davis LT, et al. Blood pressure management after endovascular therapy for acute ischemic stroke: the BEST-II randomized clinical trial. JAMA. Published September 5, 2023. doi:10.1001/jama.2023.14330