Abstract 3445: Predictors and Outcomes of Merci Device Fracture during Mechanical Thrombectomy for Acute Ischemic Stroke

Abstract

Background and Purpose: Merci device fracture is an adverse event during mechanical thrombectomy for acute ischemic stroke. The purpose of this study was to describe the frequency and predictors of this complication in acute stroke patients after thrombectomy and its impact on clinical outcome. Methods: We retrospectively analyzed acute ischemic stroke patients treated by mechanical thrombectomy with the Merci Retriever and identified the presence of device fracture. The predictors of device fracture were assessed. We evaluated the impact of device fracture on potential hemorrhage and clinical outcome. Results: Of 136 patients treated by thrombectomy, 6 (4.4%) experienced intra-procedural device fracture. Internal carotid artery occlusion was associated with device fracture (OR 13.06; 95% CI 1.47 to 115.62, P =0.01). The fractured X and L series devices were successfully ensnared by a Merci device or a microsnare in 4 patients. Compared with patients with non-fractured devices, those with fractured devices had similar rates of Thrombolysis and Myocardial Infarction (TIMI) grade II and III revascularization (66.7% versus 72.3%; p =0.67), decreased rates of arterial occlusive lesion (AOL) grade III recanalization (0% versus 48.5%; p =0.03) and longer mean procedure time (2.5 hours versus 1.8 hours; p =0.03). In patients with fractured devices, no parenchymal hematomas were found, while hemorrhagic infarction and subarachnoid hemorrhage were found in 3 and 2 patients, respectively. Decompressive craniectomy following thrombectomy for malignant edema was associated with device fracture ( P =0.02). Patients with fractured devices had similar rates of independence at discharge (modified Rankin Scale≤2, 0% versus 25%; P =0.34) and in-hospital mortality (16.7% versus 23.4%; P >0.99). Conclusions: Device fracture is relatively infrequent in acute ischemic stroke patients treated by Merci thrombectomy. Target occlusion in the internal carotid artery is an independent predictor of intra-procedural device fracture. This complication is not associated with parenchymal hematomas or poor clinical outcomes after thrombectomy.