Intra-Arterial Thrombolysis after Unsuccessful Mechanical Thrombectomy in the STRATIS Registry

BACKGROUND AND PURPOSE:Recent data suggest that intra-arterial thrombolytics may be a safe rescue therapy for patients with acute ischemic stroke after unsuccessful mechanical thrombectomy; however, safety and efficacy remain unclear. Here, we evaluate the use of intra-arterial rtPA as a rescue therapy in the Systematic Evaluation of Patients Treated with Neurothrombectomy Devices for Acute Ischemic Stroke (STRATIS) registry.MATERIALS AND METHODS:STRATIS was a prospective, multicenter, observational study of patients with acute ischemic stroke with large-vessel occlusions treated with the Solitaire stent retriever as the first-line therapy within 8 hours from symptom onset. Clinical and angiographic outcomes were compared in patients having rescue therapy treated with and without intra-arterial rtPA. Unsuccessful mechanical thrombectomy was defined as any use of rescue therapy.RESULTS:A total of 212/984 (21.5%) patients received rescue therapy, of which 83 (39.2%) and 129 (60.8%) were in the no intra-arterial rtPA and intra-arterial rtPA groups, respectively. Most occlusions were M1, with 43.4% in the no intra-arterial rtPA group and 55.0% in the intra-arterial rtPA group (P = .12). The median intra-arterial rtPA dose was 4 mg (interquartile range = 2–12 mg). A trend toward higher rates of substantial reperfusion (modified TICI  ≥ 2b) (84.7% versus 73.0%, P = .08), good functional outcome (59.2% versus 46.6%, P = .10), and lower rates of mortality (13.3% versus 23.3%, P = .08) was seen in the intra-arterial rtPA cohort. Rates of symptomatic intracranial hemorrhage did not differ (0% versus 1.6%, P = .54).CONCLUSIONS:Use of intra-arterial rtPA as a rescue therapy after unsuccessful mechanical thrombectomy was not associated with an increased risk of symptomatic intracranial hemorrhage or mortality. Randomized clinical trials are needed to understand the safety and efficacy of intra-arterial thrombolysis as a rescue therapy after mechanical thrombectomy.

Mechanical thrombectomy (MT) is a powerful therapy for patients with acute ischemic stroke with large-vessel occlusions. However, despite its proved success,^1-5 most patients do not achieve complete reperfusion^6-9 and only about half of all patients treated with MT achieve a good clinical outcome at 3 months.⁶ Because patients with complete reperfusion are 2 times more likely to have favorable outcomes than those with near-complete reperfusion,¹⁰ exploration of adjunctive or rescue therapies (RTs) to augment MT complete reperfusion is warranted.The role of intra-arterial (IA) thrombolysis has evolved from a primary therapy^11-17 to an adjunctive or RT to MT. Recently, a US survey indicated that 60.6% of neurointerventionalists use IA lytics in their practice, with the most common approach as an RT after MT.¹⁸ Previous studies on the use of IA rtPA in the context of MT either as an RT or adjunctive therapy have yielded promising data, but these studies are limited by their small sample sizes and retrospective design.^19-21 Here, in this subanalysis, we retrospectively evaluate the use of IA rtPA as an RT after unsuccessful MT in the multicenter, prospective, Systematic Evaluation of Patients Treated with Neurothrombectomy Devices for Acute Ischemic Stroke (STRATIS) registry (https://www.clinicaltrials.gov/ct2/show/{"type":"clinical-trial","attrs":{"text":"NCT02239640","term_id":"NCT02239640"}}NCT02239640?term=STRATIS&draw=2&rank=7).