Refining Angiographic Biomarkers of Revascularization

See related article, p 2650 Early revascularization is associated with improved outcomes after acute ischemic stroke. For this reason, the rate of device-specific revascularization has been used as a surrogate end point for US Food and Drug Administration clearance. However, a major problem is the lack of a standardized approach to cerebral angiographic revascularization grading. The 2 most commonly used cerebral angiographic revascularization grading systems are the Thrombolysis in Myocardial Infarction (TIMI) and Modified Thrombolysis in Cerebral Infarction (mTICI) scales. Moreover, these scales have been used in different studies to grade either recanalization of the primary arterial occlusive lesion or reperfusion of the distal tissue bed. This heterogeneous approach may explain, in part, why devices that have shown high revascularization rates in previous studies have failed to produce clinical benefits in recent trials. To address this issue, an expert panel drafted a consensus recommendation statement to standardize various aspects of angiographic revascularization grading. Among these recommendations, reperfusion scales were supported for the primary measurement of procedural success. Using the operational definition of reperfusion that was adopted by the panel, the aims of this study were to compare the TIMI and mTICI scales to determine whether one is superior for predicting clinical outcome after intra-arterial therapy Background and Purpose—Angiographic revascularization grading after intra-arterial stroke therapy is limited by poor standardization, making it unclear which scale is optimal for predicting outcome. Using recently standardized criteria, we sought to compare the prognostic performance of 2 commonly used reperfusion scales. Methods—Inclusion criteria for this multicenter retrospective study were acute ischemic stroke attributable to middle cerebral artery M1 occlusion, intra-arterial therapy, and 90-day modified Rankin scale score. Post–intra-arterial therapy reperfusion was graded using the Thrombolysis in Myocardial Infarction (TIMI) and Modified Thrombolysis in Cerebral Infarction (mTICI) scales. The scales were compared for prediction of clinical outcome using receiver-operating characteristic analysis. Results—Of 308 patients, mean age was 65 years, and median National Institutes of Health Stroke Scale score was 17. The mean time from stroke onset to groin puncture was 305 minutes. There was no difference in the time to treatment between patients grouped by final TIMI (ie, 0 versus 1 versus 2 versus 3) or mTICI grades (ie, 0 versus 1 versus 2a versus 2b versus 3). Good outcome (modified Rankin scale, 0–2) was achieved in 32.5% of patients, and mortality rate was 25.3% at 90 days. There was a 6.3% rate of parenchymal hematoma type 2. In receiver-operating characteristic analysis, mTICI was superior to TIMI for predicting 90-day modified Rankin scale 0 to 2 (c-statistic: 0.74 versus 0.68; P<0.0001). The optimal threshold for identifying a good outcome was mTICI 2b to 3 (sensitivity 78.0%; specificity 66.1%). Conclusions—mTICI is superior to TIMI for predicting clinical outcome after intra-arterial therapy. mTICI 2b to 3 is the optimal biomarker for procedural success. (Stroke. 2013;44:2509-2512.)