Recently published data from the ENCHANTED2/MT study have shed new light on the safety and efficacy of more intensive versus less intensive blood pressure lowering after mechanical thrombectomy procedures in large vessel occlusion (LVO) stroke patients.
The key finding from this trial, which is now published in The Lancet, is that “intensive control of systolic blood pressure to lower than 120mmHg should be avoided to prevent compromising the functional recovery of patients who have received endovascular thrombectomy for acute ischaemic stroke due to intracranial LVO”. Despite the fresh evidence on post-thrombectomy blood pressure lowering that these data provide, the optimal level of control here is “yet to be defined”, however.
Craig Anderson (University of New South Wales, Sydney, Australia), Jianmin Liu (Naval Medical University, Shanghai, China) and the rest of the ENCHANTED/MT investigators begin their report by asserting that the optimum systolic blood pressure after an endovascular thrombectomy procedure for acute ischaemic stroke is currently “uncertain”. As such, they aimed to compare the safety and efficacy of blood pressure lowering treatments—according to more intensive versus less intensive treatment targets—in patients with elevated blood pressure after reperfusion with a thrombectomy.
“We conducted an open-label, blinded-endpoint, randomised controlled trial [RCT] at 44 tertiary-level hospitals in China,” Anderson, Liu and colleagues detail. “Eligible patients (aged ≥18 years) had persistently elevated systolic blood pressure (≥140mmHg for >10 minutes) following successful reperfusion with endovascular thrombectomy for acute ischaemic stroke from any intracranial LVO.”
In the ENCHANTED2/MT RCT, patients were randomly assigned on a 1:1 basis—via a central, web-based programme with a minimisation algorithm—to more intensive treatments (systolic blood pressure target of <120mmHg) or less intensive treatments (target of 140–180mmHg), which were to be achieved within one hour and sustained for 72 hours.
The study’s primary efficacy outcome was functional recovery, assessed according to the distribution in scores on the modified Rankin Scale (mRS) at 90 days. Analyses were done according to the modified intention-to-treat principle, the authors note. Efficacy analyses included all randomly assigned patients who provided consent and had available data for the primary outcome, while the safety analysis included all randomly assigned patients. The investigators further note that treatment effects were expressed as odds ratios (ORs).
“Between 20 July 2020 and 7 March 2022, 821 patients were randomly assigned,” Anderson, Liu and colleagues write. “The trial was stopped after review of the outcome data on 22 June 2022 due to persistent efficacy and safety concerns.”
A total of 407 participants were assigned to the trial’s more intensive treatment group and 409 to the less intensive treatment group—of whom 404 and 406 patients, respectively, had primary outcome data available.
According to the ENCHANTED2/MT investigators, the likelihood of poor functional outcome was greater in the more intensive treatment group as compared to the less intensive treatment group (common OR 1.37 [95% confidence interval (CI) 1.07–1.76]). In contrast with the less intensive treatment group, the more intensive treatment group had more early neurological deterioration (common OR 1.53 [95% CI 1.18–1.97]) and major disability at 90 days (OR 2.07 [95% CI 1.47–2.93]), but there were no significant differences in symptomatic intracerebral haemorrhage, nor significant differences in serious adverse events or mortality, between the two groups.
These results—which were also presented at last year’s World Stroke Congress (WSC; 26–29 October, Singapore)—lead the authors to conclude their report in The Lancet by stating that such intensive blood pressure lowering should be avoided.
However, speaking at WSC 2022 following his presentation of these data, Anderson said: “While our study has now shown intensive blood pressure control to a systolic target of less than 120mmHg to be harmful, the optimal level of control is yet to be defined.”