IMPORTANCE Achieving complete reperfusion is a key determinant of good outcome in patients treated with mechanical thrombectomy (MT). However, data on treatments geared toward improving reperfusion after incomplete MT are sparse.OBJECTIVE To determine whether administration of intra-arterial urokinase is safe and improves reperfusion after failed or incomplete MT. DESIGN, SETTING, AND PARTICIPANTSThis observational cohort study included a consecutive sample of patients treated with second-generation MT from January 1, 2010, through August 4, 2017. Data were collected from the prospective registry of a tertiary care stroke center. Of 1274 patients screened, 69 refused to participate, and 993 met the observational studies inclusion criteria of a large vessel occlusion in the anterior circulation. Data were analyzed from September 1, 2017, through September 20, 2019.INTERVENTION One hundred patients received intra-arterial urokinase after failed or incomplete MT using manual microcatheter injections. MAIN OUTCOMES AND MEASURESPrimary safety outcome was the occurrence of symptomatic intracranial hemorrhage (sICH) according to the Prolyse in Acute Cerebral Thromboembolism II criteria. Secondary end points included 90-day mortality and 90-day functional independence (defined as modified Rankin Scale score of Յ2). Efficacy was evaluated angiographically, applying the Thrombolysis in Cerebral Infarction (TICI) scale. RESULTSAfter exclusion of patients with posterior circulation strokes and those treated with intra-arterial thrombolytics only, 993 patients were included in the final analyses (median age, 74.6 [interquartile range, 62.6-82.2] years; 505 [50.9%] women). Additional intra-arterial urokinase was administered in 100 patients (10.1%). The most common reason for administering intra-arterial urokinase was incomplete reperfusion (TICI<3) after MT (53 [53.0%]). After adjusting for baseline characteristics underlying case selection, intra-arterial urokinase was not associated with an increased risk of sICH (adjusted odds ratio [aOR], 0.81; 95% CI, 0.31-2.13) or 90-day mortality (aOR, 0.78; 95% CI, 0.43-1.40). Among 53 cases of partial or near-complete reperfusion and treated with intra-arterial urokinase, 32 (60.4%) had early reperfusion improvement, and 18 of 53 (34.0%) had an improvement in TICI grade. Correspondingly, patients treated with intra-arterial urokinase had higher rates of functional independence after adjusting for the selection bias favoring a priori poor TICI grades in the intra-arterial urokinase group (aOR, 1.93; 95% CI, 1.11-3.37). CONCLUSIONS AND RELEVANCEIn selected patients, adjunctive treatment with intra-arterial urokinase during or after MT was safe and improved angiographic reperfusion. Systemic evaluation of this approach in a multicenter prospective registry or a randomized clinical trial seems warranted.

ObjectiveTo test the hypothesis that selection by initial imaging modality (MRI vs CT) is associated with rate of futile recanalizations (FR) after mechanical thrombectomy (MT), we assessed this association in a multicenter, retrospective observational registry (BEYOND-SWIFT, NCT03496064).MethodsIn 2011 patients (49.7% female, median age 73 [61–81]) included between 2009 and 2017, we performed univariate and multivariate analyses regarding the occurrence of FR. FR were defined as 90 days modified Rankin Scale (mRS) 4–6 despite successful recanalization in patients selected by MRI (N = 690) and CT (N = 1,321) with a sensitivity analysis considering only patients with mRS 5–6 as futile.ResultsMRI as compared to CT resulted in similar rates of subsequent MT (aOR 1.048, 95% CI 0.677–1.624). Rates of FR were as follows: 571/1,489 (38%) FR mRS 4–6 including 393/1,489 (26%) FR mRS 5–6. CT based selection was associated with increased rates of futile recanalizations compared to MRI (44% [41%–47%] vs 29% [25%–32%], p < 0.001; aOR 1.77 [95%-CI: 1.25–2.51]). These findings were robust in sensitivity analysis. MRI-selected patients had a delay of approximately 30 minutes in workflow metrics in real-world university comprehensive stroke centers. However, functional outcome and mortality were more favorable in patients selected by MRI compared to patients selected with CT.ConclusionsCT-selection for MT was associated with an increased risk of futile recanalizations as compared to MR-selection. Efforts are still needed to shorten workflow delays in MRI patients. Further research is needed to clarify the role of the initial imaging modality on FR occurrence and to develop a reliable FR prediction algorithm.