BEST-II Throws Cold Water on Already-Tepid BP Lowering After Stroke Thrombectomy

DALLAS -- There's no practical way forward for the strategy of moderate blood pressure (BP) control immediately after endovascular stroke treatment, following results from the BEST-II trial.

Targeting systolic BP (SBP) to <160 mm Hg or <140 mm Hg following endovascular therapy (EVT) was associated with a trend in the direction of benefit in terms of infarct volume at 36 hours (on MRI or CT, adjusted for baseline Alberta Stroke Program Early CT Score). However, the confidence interval also covered potential harm, reported Eva Mistry, MBBS, MSCI, of the University of Cincinnati, during the American Stroke Association's International Stroke Conference.

As for the other primary endpoint, 90-day utility-weighted modified Rankin score (adjusted for baseline), tighter SBP control trended slightly in the direction of harm, though the confidence interval did not rule out a marginal benefit.

Altogether, the results do not meet criteria that would suggest that subjecting moderate BP control to a larger pivotal trial would be totally futile, Mistry said.

However, given that the trends are in the direction of harm and only marginal benefit -- though the study was not statistically designed to detect benefit -- her group believes that continuing pivotal inquiry of lower post-EVT SBP targets may not be the best use of resources, she added.

These results were consistent with those of two older trials: BP-TARGET, which produced a neutral result for a low BP target (100-129 mm Hg vs 130-185 mm Hg), and ENCHANTED2/MT, which was stopped early due to worse outcomes in the group targeting SBP <120 mm Hg (vs 140-180 mm Hg).

The hope was that moderate SBP targets of <140 mm Hg or <160 mm Hg would show more promise in improving outcomes for stroke patients undergoing EVT in BEST-II.

Instead, the predictive probability of success for BP control was just 28% in a hypothetical trial with 2,400 people, Mistry's group found.

"Although these results have dampened the enthusiasm of pursuing a much larger pivotal trial of intensive BP lowering, I hope that more evidence testing moderate BP lowering ranges becomes available moving forward," said Anthony Kim, MD, a stroke neurologist at the University of California San Francisco, who was not involved in the study.

"Until then, I think it is reasonable to continue to avoid very low SBP 120-130 targets and to avoid excursions into this range even if higher BPs are targeted, though this is largely based on the pre-existing pre-BEST-II RCT data," he told MedPage Today.

American and European guidelines currently recommend maintaining post-EVT BP at <180/105 mm Hg. However, real-world practice is heterogeneous, as previously noted in a 2018 survey.

"Individual patients might require lowering of blood pressure due to medical and neurological reasons; however, it should not be done as blanket practice with all patients," Mistry said in a press release.

"There is always the concern if blood pressure is lowered too much in patients who are having an acute ischemic stroke that it could make the size of their stroke worse by reducing already compromised blood flow in that area," she explained.

The BEST II investigators enrolled 151 EVT recipients across three centers from 2020 to 2022. After exclusions for unsuccessful EVT or medical concerns, they were left with 120 patients randomized to one of the three SBP targets (using nicardipine in the first line) for 24 hours immediately after EVT.

Mean patient age was 69.6 years, 57.5% were women, and 87.5% were white. The lowest SBP target group (<140 mm Hg) tended to be older and comprised more women compared with the others.

Mistry noted the good separation in BP achieved between the highest and lowest target groups, but only moderate separation between the 180 and 160 groups. This was supported by mean post-EVT hourly BPs:

• Target ≤180 mm Hg: mean post-EVT hourly BP 129 mm Hg (90th percentile 157 mm Hg; antihypertensives used in 25%)
• Target <160 mm Hg: 130.3 mm Hg (90th percentile 153 mm Hg; antihypertensives used in 55%)
• Target <140 mm Hg: 121.8 mm Hg (90th percentile 139 mm Hg; antihypertensives used in 72.5%)

Secondary safety outcomes did not favor tighter SBP control. The incidence of any intracerebral hemorrhage (ICH) at 36 hours was 30% for the two highest targets and 35% for the strictest 140 mm Hg target. For symptomatic ICH, the rates were 5%, 2.5%, and 5%, respectively.

Seven out of the eight patients experiencing serious adverse events were in the <160 and <140 mm Hg groups.

OPTIMAL-BP, CRISIS I, and other ongoing trials are expected to provide additional insights on BP control after stroke thrombectomy.

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