Worsened Functional Outcome in Stroke Linked to Maximum Systolic Blood Pressure Post-EVT

None of the associations between blood pressure and outcomes were modified by successful reperfusion at the end of the endovascular treatment procedure.

Worsened functional outcome, greater risk of symptomatic intracranial hemorrhage (sICH), and more severe early neurological deficits were all found to be associated with maximum systolic blood pressure (SBP) in the 6 hours following endovascular treatment (EVT) for stroke due to large artery occlusion in the anterior circulation.

Lead author Noor Samuels, PhD candidate, Erasmus Medical Center, and colleagues evaluated maximum, minimum, and mean SBP in patients of 8 MR CLEAN Registry centers. SBP values were collected and recorded between the end of the EVT procedure and 24 hours after EVT or until discharge from the intervention center. The primary outcome measure was functional outcome according to the modified Rankin Scale (mRS).

A total of 1161 patients treated with EVT were included in the analysis, with a median of 7 (interquartile range [IQR], 4-11) available number of SBP measurements in the first 6 hours. Those who demonstrated higher maximum SBP within that time period were found to be more likely to have worse functional outcomes than patients with lower maximum SBP (adjusted common OR, 0.93 per 10 mm Hg [95% CI, 0.88-0.98]).

Secondary outcomes included National Institutes of Health Stroke Scale (NIHSS) score, which indicated neurological deficit at 24 to 48 hours after EVT. At the conclusion of the study, patients with higher maximum SBP not only showed larger neurological deficit (Aß, 0.31 [95% CI, 0.14-0.49), but an increased risk of sICH (adjusted OR, 1.17 [95% CI, 1.02-1.36]). Notably, these patients were not associated with an increased risk of death (adjusted OR, 1.02 [95% CI, 0.95-1.08]). Similarly, the association between higher maximum SBP and worse functional outcome was also observed in the sensitivity analysis during the first 24 hours (adjusted common OR, 0.90 per 10 mm Hg [95% CI, 0.85-0.94]).

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Using a multivariate model that compared a linear SBP term to a model allowing 3 knots for SBP, investigators found the association between minimum SBP and functional outcome to be nonlinear (likelihood ratio test, P <.001). They then obtained effective effect estimates for lower minimum and higher minimum SBP separately, with infection point at around 124 mm Hg. Minimum SBP below that point and minimum SBP above that point were both associated with worse functional outcome (SBP <124 mm Hg: adjusted common OR per 10 mm Hg decrement, 0.85 [95% CI, 0.76-0.95]; SBP >124 mm Hg: 0.81 per 10 mm Hg increment [95% CI, 0.71-0.92]).

A separate analysis evaluated low and higher mean SBP with an infection point at around 138 mm Hg. Mean SBP below that point were associated with higher likelihood of extracranial hemorrhage (adjusted OR, 1.66 per 10 mm Hg decrement [95% CI, 1.07-2.51]). Mean SBP higher than 138 mm Hg did not show any association with any of the other outcomes.

Investigators found no interaction between extend of reperfusion and the relation of SBP with functional outcome (P values for interaction: maximum SBP, P = 0.84; minimum SBP, P = 0.49; and mean SBP, P = 0.99). Additionally, there was no interaction for any of the other secondary outcomes such as mRS score of at least less than 2 at 90 days, NIHSS scores between 24-48 hours, mortality at 90 days, sICH, extracranial hemorrhage, and new ischemic stroke.

During the 6 hours following EVT, there was a decline in maximum SBP from baseline for both reperfusion categories, with higher maximum SBPs among patients with unsuccessful reperfusion at the end of EVT procedure compared with patients with successful reperfusion.

REFERENCE
Samuels N, van de Graaf R, van den Berg CAL, et al. Blood pressure in the first 6 hours following endovascular treatment for ischemic stroke is associated with outcome. Stroke. Published online September 20, 2021. doi:10.1161/STROKEAHA.120.033657