MUNICH, GERMANY – suggests results from the OPTIMAL-BP trial.
The research, presented at the annual European Stroke Organisation Conference, supports the latest U.S. and European guidelines, which recommend a relatively high upper SBP limit.
For the trial, which was halted early, more than 300 patients who successfully underwent IAT for acute ischemic stroke were randomly assigned to intensive or conventional BP management within 2 hours of recanalization.
Patients in the intensive group were 44% less likely than those assigned to conventional management to have a favorable outcome of a modified Rankin Scale (mRS) score of 0-2 at 3 months, while having similar rates of adverse outcomes.
The results suggest that intensive BP lowering in the 24 hours after recanalization leads to an increased risk of disability without decreasing the risk of intracerebral hemorrhage (ICH) or death, said study presenter Hyo Suk Nam, MD, PhD, department of neurology, Yonsei (South Korea) University.
Consequently, the trial “does not support intensive blood pressure management” in that early post-IAT period, although the “optimal blood pressure range remains unclear and requires more investigation,” he said.
Dr. Nam added that the results suggest, “despite recanalization, some areas in the ischemic brain may have already been damaged,” or that surrounding areas continue to have reduced blood circulation.
He believes that these areas may have reduced capacity for autoregulation and so “may not effectively counteract sudden drops in blood pressure.
“Thus, intensive blood pressure lowering may further reduce blood flow ... and exacerbate ischemic injury.”
On the other hand, the conventional group confirmed prior studies indicating that high SBP is associated with poor outcomes.
Dr. Nam suggested that increased BP “may be a physiological response to the acute stress of stroke,” but that the adverse outcomes in some patients “might reflect stroke severity rather than being a direct effect of raised blood pressure.”
Session cochair Carlos Molina, MD, director of the stroke unit and brain hemodynamics at Vall d’Hebron Hospital, Barcelona, commented that “it’s very important to remember that the guidances are endorsed by the results of this study.
He said in an interview that “intensive blood pressure lowering harms the brain, especially just after reperfusion.
“So, the results are in line with the previous concept that we need to be careful, as intensive blood pressure lowering is associated with clinical deterioration and poor outcomes.”
He agreed with Dr. Nam that, with high BP also being harmful, the optimal range is currently unclear.
Dr. Molina underlined, however, that, in the absence of further studies, “we have to stick to the guidelines.”
Dr. Nam pointed out that, while high BP can result in reperfusion injury or ICH, “too low blood pressure can worsen cerebral ischemia.”
Yet the management of BP after successful recanalization with IAT is “largely unknown.”
He noted that, while both the European Stroke Organisation and American Heart Association/American Stroke Association guidelines recommend that BP should be kept below 180/105 mm Hg in patients who have undergone successful recanalization, the evidence class for this recommendation is “weak.”
Furthermore, observational studies have indicated that higher maximum or average SBP is associated with poor outcomes, but two multicenter clinical trials of intensive BP lowering after IAT, BP-TARGET and ENCHANTED2/MT, had conflicting results.
The researchers therefore investigated whether intensive BP management would result in better clinical outcomes in the 24 hours after successful recanalization with IAT.
They conducted a multicenter, open-label trial in which patients aged 20 years and older who underwent IAT for acute ischemic stroke with large cerebrovascular occlusion and had an SBP of at least 140 mm Hg were recruited from 19 centers in South Korea between June 2020 and November 2022.
The patients were randomly assigned within 2 hours of successful recanalization to intensive BP management, targeting an SBP less than 140 mm Hg, or conventional management, targeting an SBP of 140-180 mm Hg.
Clinicians could use local treatment protocols based on available intravenous BP-lowering drugs. BP was measured every 15 minutes for the first hour after randomization and then hourly for 24 hours.
The trial was terminated early because of safety concerns after the ENCHANTED2/MT trial revealed a negative impact on mRS scores at 3 months with intensive BP management.
Of 1,606 potentially eligible patients with acute ischemic stroke treated with IAT, 306 were randomly assigned, with 155 in the intensive group and 150 in the conventional group included in the primary analysis.
The mean age was 73.1 years, and 40.3% were women. The average National Institutes of Health Stroke Scale (NIHSS) score prior to IAT was 13. The mean time from stroke onset to randomization was 480 minutes (interquartile range, 320-820 minutes).
At 24 hours, the mean SBP in the intensive group was 129.2 mm Hg versus 138.0 mm Hg in the conventional group, for a between-group difference of 9.6 mm Hg (95% confidence interval, –12.2 to –6.9, P < .001).
Patients in the intensive group spent 80.3% of the first 24 hours with SBP less than 140 mm Hg versus 54.2% in the conventional group (P < .001). In contrast, conventional group patients spent 42.1% of the first 24 hours with SBP 140-180 mm Hg versus 14.2% in the intensive group.
Crucially, Dr. Nam showed that patients in the intensive BP-lowering group were significantly less likely than those in the conventional group to have a favorable outcome, defined as an mRS score of 0-2, at 3 months, at 39.4% versus 54.4%, or an adjusted odds ratio of 0.56 (95% CI, 0.33-0.96, P = .034).
Moreover, a poor outcome was 1.84 (95% CI, 1.17-2.91) times more common in the intervention group than the conventional group, Dr. Nam reported, with a number needed to harm of 6.6.