Recanalization after thrombolysis in stroke patients Predictors and prognostic implications A. Zangerle, MD; S. Kiechl, MD; M. Spiegel, MD; M. Furtner, MD; M. Knoflach, MD; P. Werner, MD; A. Mair, MD; G. Wille, MD; C. Schmidauer, MD; K. Gautsch, MD; T. Gotwald, MD; S. Felber, MD; W. Poewe, MD; and J. Willeit, MD Abstract—Objective: To estimate rates, predictors, and prognostic importance of recanalization in an unselected series of patients with stroke treated with IV thrombolysis. Methods: We performed a CT angiography or transcranial Doppler (TCD) follow-up examination 24 hours after IV thrombolysis in 64 patients with documented occlusion of the intracranial internal carotid or middle cerebral artery (MCA). Complete recanalization was defined by a rating of 3 on the Thrombol- ysis in Myocardial Infarction or 4/5 on the Thrombolysis in Brain Ischemia grading scales. Information about risk factors, clinical features, and outcome was prospectively collected by standardized procedures. Results: Complete recanalization was achieved in 36 of the 64 patients (56.3%). There was a nonsignificant trend of recanalization rates to decline with a more proximal site of occlusion: 68.4% (M2 segment of MCA), 53.1% (M1 segment), and 46.2% (carotid T) (p for trend  0.28). Frequencies of vessel reopening were markedly reduced in subjects with diabetes (9.1% vs 66.0% in nondiabetics, p  0.001) and less so in subjects with additional extracranial carotid occlusion (p  0.03). Finally, complete recanaliza- tion predicted a favorable stroke outcome at day 90 independently of the information provided by age, NIH Stroke Scale, and onset-to-needle time. Conclusions: We found a high rate of vessel recanalization after IV thrombolysis occlusion. However, recanalization was infrequent in patients with diabetes and extracranial carotid occlusion. Information on recanalization was a powerful, early predictor for clinical outcome. NEUROLOGY 2007;68:39–44 IV thrombolysis with tissue plasminogen activator (tPA) is the first-choice therapy for ischemic stroke if applicable within 3 hours. 1,2 There is broad consen- sus that thrombolysis improves clinical outcome by resolving the occlusive clot and restoring adequate blood flow. 2 The rate of successful recanalization af- ter IV tPA, however, is not well established because the large intervention trials have not systematically assessed vessel status before and after therapy. The few data available are from a limited set of stroke databases and case series, 3-20 most of which were comparatively small and from secondary referral centers. Moreover, these studies were partly retro- spective in design, and some applied continuous TCD monitoring, 3-6,12,13,15 which, by itself, may affect recanalization. The current prospective study aims at assessing the frequency of recanalization after IV thrombolysis in a series of 64 consecutive and unselected patients with documented occlusion of the intracranial inter- nal carotid artery (ICA) or middle cerebral artery (MCA). An additional focus will be on the identifica- tion of predictors of vessel recanalization and on its prognostic potential. Methods. Study subjects. Between 2002 and 2004, 100 pa- tients with anterior circulation stroke were treated with tPA at the stroke unit of the Innsbruck University Hospital (Depart- ment of Neurology). During the study period, the Innsbruck University Hospital was the only thrombolysis facility in North- ern Tyrol—a survey area of 500,000 inhabitants—and all pa- tients with suspected acute stroke potentially eligible for thrombolysis were referred to the hospital. Accordingly, the study cohort represents an unselected series of thrombolysis patients. tPA was given at the usual dose of 0.9 mg/kg. 2 Stan- dard inclusion and exclusion criteria were applied. 2 As a single exception, patients older than 80 years were treated if other- wise healthy and eligible. As a hospital standard and as part of the protocol, each patient underwent cranial CT, CT angiogra- phy (CTA), and CT perfusion scan before and 24 (4) hours after treatment. If the CT protocol was not feasible or if reser- vations about application of contrast agents existed (allergy, renal insufficiency, or hyperthyreosis), noncontrasted CT plus transcranial Doppler (TCD) was performed. In 26 subjects, oc- clusions of the ICA or MCA (M1/M2 segments) could not be detected. Most of these patients either had occlusions of periph- Additional material related to this article can be found on the Neurology Web site. Go to www.neurology.org and scroll down the Table of Con- tents for the January 2 issue to find the title link for this article. From the Departments of Neurology (A.Z., S.K., M.S., M.F., M.K., P.W., A.M., G.W., C.S., W.P., J.W.) and Diagnostic Radiology (K.G., T.G., S.F.), Innsbruck Medical University, Innsbruck, Austria. Disclosure: The authors report no conflicts of interest. Received June 14, 2006. Accepted in final form September 27, 2006. Address correspondence and reprint requests to Johann Willeit, Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria; e-mail: Johann.willeit@uibk.ac.at Copyright © 2007 by AAN Enterprises, Inc. 39