Early recurrent ischemic events after mechanical thrombectomy: effect of post-treatment intracranial hemorrhage

Objective: Patients with intracranial hemorrhages (ICH) after mechanical thrombectomy (MT) may have a higher risk of early recurrent embolism (ERE) because of delayed initiation of anticoagulants. We assessed the rate of ischemic events in the early period after MT and the association with post-MT ICH. Methods: Patients who underwent MT in our institute were retrospectively reviewed. ERE was defined as recurrent ischemic stroke and systemic embolism within 14 days after MT. The association between ERE and parenchymal hematoma (PH) was assessed. Multivariable regression analysis and inverse probability of treatment weighting was used to adjust for differences in baseline characteristics between patients with and without PH. Results: A total of 307 patients (median age, 78 years; female, 47%; median baseline National Institutes of Health Stroke Scale score, 19) were included. ERE was observed in 12 of 307 patients (8 strokes, 4 systemic embolisms; 3.9%). Median time from MT to ERE was 6.5 days (IQR, 3–8 days). PH occurred in 21 patients (6.8%). Median time from MT to initiating oral anticoagulants was longer in patients with PH (8 days) than in those without (3 days) (p < 0.01). In both unweighted and weighted multivariable analysis, PH was significantly associated with an increased risk of ERE (unweighted odds ratio, 10.60; 95% CI, 2.66–42.23; weighted odds ratio, 12.34; 95% CI, 2.49–61.07). Conclusions: ERE occurred in about 4% of patients after MT. PH after MT was associated with delayed initiation of oral anticoagulants and an increased risk of recurrent ischemic events. Clinical trial registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02251665.