LOS ANGELES—Decreases in blood pressure during endovascular therapy are common and associated with worse functional outcomes, according to research presented at the 70th Annual Meeting of the American Academy of Neurology.
Patients with acute ischemic stroke have impaired cerebral autoregulation, which raises the need for blood pressure management to avoid secondary neurologic injury. Neurologists have not reached a consensus on the optimal management of blood pressure during endovascular therapy, however.
Anson Wang, a postgraduate research associate at the Yale School of Medicine in New Haven, Connecticut, and colleagues prospectively enrolled into their study patients with acute ischemic stroke due to large-vessel occlusion who were scheduled to undergo endovascular therapy between 2014 and 2018 at Yale-New Haven Hospital. Nils Petersen, MD, MSc, Assistant Professor of Neurology at Yale School of Medicine, led the study. The researchers monitored admission mean arterial pressure (MAP) and intraprocedural MAP using a noninvasive blood pressure cuff or an intra-arterial catheter. They calculated change in MAP as the difference between admission MAP and lowest MAP during endovascular therapy. Sustained hypotension was measured as the area between admission MAP and continuous measurements of intraprocedural MAP (aMAP).
Mr. Wang and colleagues examined associations between blood pressure and functional outcome at discharge and 90 days, as measured using the modified Rankin Scale (mRS), using ordinal logistic regression. They defined an unfavorable outcome as an mRS score of 3 or more.
Most Patients Had Reductions in Blood Pressure
The investigators included 115 patients in the study. Participants’ mean age was 72, and mean NIH Stroke Scale (NIHSS) score was 18. Ninety-day outcomes were available for 78 patients. Admission MAP was 107 mm Hg. Approximately 89% of patients had MAP reductions during endovascular therapy (mean, 26 ± 21 mm Hg). Median reduction in MAP among patients with favorable outcomes was 18 mm Hg, compared with 34 mm Hg among patients with unfavorable outcomes.
After Mr. Wang and colleagues adjusted the data for age, gender, and admission NIHSS, change in MAP was independently associated with higher mRS scores at discharge and at 90 days. Every 10-mm Hg reduction in MAP from admission during endovascular therapy was associated with a 26% increase in the likelihood of an unfavorable functional outcome at discharge and a 32% increase in the likelihood of an unfavorable functional outcome at 90 days. The association between aMAP and outcome was highly significant at discharge and 90 days.
Blood Pressure Change May Affect Infarct Volume
To investigate how decreases in blood pressure could cause worse functional outcomes, Mr. Wang and colleagues measured MRI scans of 57 patients with a Thrombolysis in Cerebral Infarction (TICI) scale score of 2b or 3. The mean time between scans was 28 hours. They observed an association between larger final infarct volumes and higher drops in blood pressure. The median infarct volume in patients with a good outcome was approximately 12 cm3.
The limitations of the study include the retrospective data analysis and the lack of continuous blood pressure measurements during the period between arrival at the emergency department and presentation for surgery. Nevertheless, “these results underline the importance of blood pressure management during endovascular therapy and highlight the need for further investigation of active blood pressure management strategies to optimize clinical outcomes,” said Mr. Wang.