Association of 24-hour blood pressure parameters post-thrombectomy with functional outcomes according to collateral status

Introduction: Elevation of blood pressure (BP) after mechanical thrombectomy (MT) can theoretically restore perfusion to the ischemic brain tissue, but it comes at a risk of causing reperfusion injury. We aim to determine the association of 24-h post-MT BP parameters with clinical outcomes depending on the pre-MT collateral status.

Methods: We performed a retrospective chart review of patients who underwent MT at a comprehensive stroke center from 7/2014 to 12/2020. The patients were divided into good versus poor collateral groups depending on their collateral status. A board-certified neuroradiologist, who was blinded to the clinical outcomes, used collateral grading score of Miteff ≥3 to designate good collaterals on the pre-MT CT Angiogram. A binary logistic regression analysis was performed, controlling for baseline parameters, with the 24-h post-MT BP parameters as predictors. The outcomes were functional dependence [3-month mRS (3-6)] and mortality.

Results: A total of 220 met the inclusion criteria. In the multivariable analysis, for patients with poor collaterals, the parameters of higher mean SBP (131.7 ± 12.7 vs. 122.3 ± 14.2; OR, 1.06; 95% CI, 1.01-1.11; P 0.022), higher mean MAP (91.2 ± 8.2 vs. 86.1 ± 6.3; OR, 1.13; 95% CI, 1.03-1.23; P 0.015) and a higher maximum SBP (156.3 ± 13.7 vs. 145.3 ± 19.1; OR, 1.05; 95% CI, 1.01-1.1; P 0.019) were significantly associated with functional dependence at 3-months. For patients with good collaterals, the parameters of lower 24-h mean DBP (69.1 ± 11.1 vs. 73.8 ± 11 95% CI, OR, 0.96; 95% CI, 0.92-1; P 0.025) was significantly associated with higher mortality at 3-months.

Conclusion: Our study demonstrates that there is a significant difference with respect to certain 24-h post-MT BP parameters in patients on clinical outcomes depending on their collateral status. In our study, some higher BP parameters were associated with worse outcomes in patients with a poor collateral profile, however, this effect was not replicated in patients with a good collateral profile.