Importance of Cerebral Artery Recanalization in Patients With Stroke With and Without Neurological Improvement After Intravenous Thrombolysis

Abstract

Recanalization status after intravenous thrombolysis (IVT) in patients with ischemic stroke is a reference point to proceed with a rescue reperfusion intervention, although early neurological improvement (NI) may preclude endovascular procedures. We aimed to evaluate the importance of restoration of blood flow at the arterial occlusion site in subgroups of patients with stroke stratified by early NI after IVT. The following patients were recruited from the Safe Implementation of Treatment in Stroke-International Stroke Thrombolysis Register: (1) with baseline vessel occlusion documented by computed tomographic (CT) or magnetic resonance (MR) angiography and follow-up angioimaging between 22 and 36 hours after IVT available; and (2) with dense cerebral artery sign on admission CT scan and results of follow-up CT reported. Recanalization at 24 hours was defined as absence of vessel occlusion or as resolution of dense cerebral artery sign on follow-up 22- to 36-hour imaging. NI was assessed at 2 hours and 24 hours after IVT and was defined as improvement by 20% from baseline National Institute of Health Stroke scale score. Primary outcome measure was independence, defined as modified Rankin scale score 0 to 2 after 3 months. Of 28136 cases registered between December 2003 and November 2009, 5324 cases (19%) met the inclusion criteria. Patients with both NI at 2 hours post-treatment and vessel recanalization had the best chances to achieve independence at 3 months (adjusted odds ratio, 15.8; 95% confidence interval, 12.5-20.0), followed by those who had NI despite persistent occlusion (adjusted odds ratio, 4.7; 95% confidence interval, 3.6-6.1); and those without NI despite recanalization (adjusted odds ratio, 2.7; 95% confidence interval, 2.2-3.3). Recanalization of an occluded artery in acute stroke is associated with favorable functional outcome both in patients with and without NI after IVT. In future evaluations of mechanical thrombectomy and other additional strategies, recanalization should be considered in patients with persisting occlusion after IVT even after significant NI.