BASEL, SWITZERLAND — New findings challenge the practice of rapidly lowering blood pressure (BP) in acute ischemic stroke to allow for speedy thrombolysis.
The observational cluster study showed that , even though this meant fewer patient received thrombolysis.
“We found insufficient evidence to recommend active blood pressure lowering in patients with ischemic stroke who have blood pressure levels exceeding the guidelines but are otherwise eligible for thrombolytic therapy,” said senior study author Nyika D. Kruyt, MD, PhD, Leiden University Medical Center, the Netherlands.
“Our results suggest that if the blood pressure is too high for thrombolysis, then it is best to wait and only treat with thrombolysis if the blood pressure drops spontaneously,” Dr. Kruyt said.
The findings were presented at the European Stroke Organisation Conference (ESOC) annual meeting and published online in The Lancet Neurology.
Guidelines Without Evidence?
Owing to concerns about high BP increasing the risk for intracerebral hemorrhage after thrombolysis, the original trials evaluating thrombolysis in stroke set an arbitrary threshold of 185/110 mm Hg, which has been incorporated into stroke guidelines. These trials cautioned against lowering BP rapidly, which is not included in guidelines.
Most stroke centers therefore tend to rapidly lower BP in patients who have values greater than 185/110 mm Hg and who are otherwise eligible for thrombolysis, investigators noted. Because thrombolysis is more effective the earlier it is administered, there is some urgency to reduce the BP quickly when patients first arrive at the hospital.
“But there has never been any evidence for the lowering of blood pressure with IV [intravenous] antihypertensives before thrombolysis, and some centers have never adopted this approach because of concerns that a rapid decline in blood pressure may reduce perfusion of the brain at a time when there is already ischemia present,” Dr. Kruyt noted.
However, if BP is lowered quickly, there is a greater chance that patients will not be able to receive thrombolysis because the 4.5-hour time limit could be exceeded.
For the prospective, observational TRUTH study, researchers compared outcomes in 853 patients treated at 27 stroke centers in the Netherlands with an active BP-lowering strategy vs 199 patients treated at 10 hospitals with no such strategy.
Baseline characteristics of participants in the two groups were similar.
Results showed a strong trend toward worse outcomes in participants whose BP was lowered, with an adjusted odds ratio (aOR) for a shift toward a worse 90-day functional outcome on the modified Rankin Scale of 1.27 (95% CI, 0.96-1.68).
This was despite the fact that many more patients whose BP was reduced received thrombolysis (94% vs 52% of those with no BP lowering) and had shorter times to treatment, with average door-to-needle times of 35 minutes (vs 47 minutes among those with no BP lowering).
Symptomatic intracranial hemorrhage occurred in 5% of the active BP-lowering group versus 3% of those who did not have their BP lowered (aOR, 1.28; 95% CI, 0.62-2.62).