Background: Endovascular reperfusion therapy (ERT) for acute large vessel occlusion limits infarct expansion and improves clinical outcomes but successful reperfusion may also increase risk of reperfusion injury and parenchymal hemorrhage (PH). We explored the association between levels of reperfusion and risk of PH.
Methods: In a post-hoc analysis of the endovascular arm of the Interventional Management of Stroke-III randomized clinical trial, we assessed the association between levels of reperfusion (TICI0-1, 2A and 2B/3) and hemorrhage risk (PH1/2) in unadjusted and adjusted models controlling for stroke severity, final infarct volume (FIV) and level of occlusion.
Results: Out of 434 participants who received ERT, 311 had documented TICI reperfusion grades (TICI 0-1: 84 [27%], TICI 2A: 108 [34.7%], TICI 2B/3: 119 [38.3%]). PH occurred in 42 (13.5%) patients. Patient characteristics are shown in Figure A. Higher reperfusion scores were associated with lower FIV (N=264, Mann-Whitney p<0.001 Figure B). Univariable predictors (p<0.10) of PH included FIV (p<0.0001), 24-hour NIHSS (p<0.0001) and TICI reperfusion grade (p=0.08). Compared to the TICI 0-1 group, TICI 2A was associated with higher odds of PH (OR=3.9, 1.26-12.1, p=0.014) while odds of PH in TICI 2B/3 reperfusion was similar to the TICI 0-1 category (OR=1.76, 0.73-4.26, p=0.2) after controlling for FIV or 24-hour NIHSS (Fig. C).
Conclusions: Risk of PH appears to be highest in patients with intermediate levels of reperfusion even after adjusting for infarct size. While the reasons for this need investigating, we propose that the infarct size-mitigating effect of intermediate reperfusion may be partially offset by increased risk of PH. Our exploratory results emphasize the importance of achieving complete reperfusion during the treatment of acute LVO stroke patients.