Revascularization end points in stroke interventional trials - Recanalization versus reperfusion in IMS-I

Background and Purpose - The acute stroke literature lacks a standard convention regarding the critical end point of revascularization. Two distinct parameters may be clinically important: (1) recanalization of the primary arterial occlusive lesion (AOL) and (2) global reperfusion of the distal vascular bed. We sought to determine their relationship in the Interventional Management of Stroke (IMS) Phase I trial of combined intravenous (IV) and intraarterial (IA) recombinant tissue plasminogen activator. Methods - Sixty-one angiograms were reanalyzed using recanalization and reperfusion scores. The AOL Score was defined as: 0 = no recanalization of the primary occlusion, I = incomplete or partial recanalization of the primary occlusion with no distal flow, II = incomplete or partial recanalization of the primary occlusion with distal flow, or III = complete recanalization of the primary occlusion with distal flow. The Thrombolysis in Myocardial Infarction (TIMI) Score was defined as: 0 = no perfusion, 1 = perfusion past the initial occlusion but no distal branch filling, 2 = perfusion and incomplete or slow distal branch filling, or 3 = full perfusion with filling of all distal branches. We compared the 2 scores with one another and with good clinical outcome (modified Rankin Score zero to 2). Results - AOL and TIMI scores showed modest agreement (kappa, 0.30; confidence interval, 0.16 to 0.44). Good clinical outcome was seen in 49% of patients with AOL II/III scores (P = 0.055) and 54% with TIMI 2/3 scores (P = 0.019). The 2 methods did not significantly differ in predicting outcome (P = 0.13). Conclusions - AOL recanalization and TIMI reperfusion scores comparably predict clinical outcome in this treatment paradigm. Other modalities may show different relationships between these 2 revascularization end points. Future studies should distinguish between these parameters semantically and methodologically.