Abstract WMP3: Predictors And Outcomes Associated With Rescue Therapy In SWIFT

Abstract

Introduction: In the Solitaire With the Intention For Thrombectomy (SWIFT) trial, rescue therapy was used when the Solitaire or Merci device was unable to restore vessel patency. Markers for non-recanalization in acute stroke have been reported for IV tPA, however similar predictors are not known for endovascular therapy. We sought to identify predictors and outcomes associated with rescue therapy in the SWIFT trial. Methods: Rescue therapy was defined per SWIFT study protocol, and included the use of an alternative device, agent, or maneuver following failure to recanalize with 3 retrieval attempts using the initial device. Clinical, angiographic, and demographic data was reviewed. Statistical analysis was performed using t-test or Wilcoxon methods and multivariate logistic regression analyses. Results: Among a total of 144 patients enrolled (31 roll-in phase Solitaire patients, and 113 randomized patients, 58 Solitaire, 55 Merci), 43 (29.9%) required rescue therapy. Baseline demographics for patients with and without rescue therapy were no different. Rescue therapy was used in a higher percentage of patients randomized to Merci than Solitaire (43% vs 21%, p = 0.009). Patients with rescue therapy experienced longer time to recanalization (p < 0.001), a lower percentage of successful recanalization (p < 0.001), and a lower percentage of good outcome (p = 0.009). In multivariate analysis, predictors of rescue therapy were those patients randomized to the Merci group (OR 3.99, 95% CI 1.58, 10.10) and patients over age 80 years (OR 3.51, 95% CI 1.06, 11.64). Non-significant trends toward an increased need for rescue therapy were observed in patients with hypertension (p = 0.09), and occlusions of the carotid terminus and M1 MCA compared with other locations (p = 0.10). No association was observed with rescue therapy and afib (p = 0.47) or IV tPA failure (p = 0.49), and rescue therapy was not associated with symptomatic ICH (p = 0.43). Conclusions: Predictors of rescue therapy included Merci treatment group and age, while trend toward an increased need of rescue therapy was observed with hypertension and proximal clot location. Rescue therapy was associated with fewer good outcomes. These findings may reflect targets for improvement in endovascular therapy.