Simonsen, Claus Z.

Background: Tissue reperfusion is a critical determinant of outcomes after intra-arterial therapy (IAT). However, there is no standardized method for grading angiographic reperfusion. We sought to compare the two most commonly used reperfusion scales, TIMI and modified TICI (m-TICI), for predicting good long-term outcome following IAT. Methods: From a multicenter database, we evaluated acute stroke patients presenting with middle cerebral artery (MCA) M1 occlusions who underwent IAT. Clinical and angiographic data were collected. Reperfusion for each case was graded using the TIMI and m-TICI scales. The primary distinction between these scales is that partial reperfusion (TIMI 2) is sub-divided into minor (m-TICI 2A: <50%) and major (m-TICI 2B: 50-99%) grades in the m-TICI system. The performance of these scales for predicting a good 90-day outcome (mRS 0-2) was evaluated using the c-statistic. Results: There were 313 acute stroke patients with MCA M1 segment occlusions who underwent IAT at 6 academic centers; 171 (54.6%) were female. Mean age was 65.3±16.5 years. There were 157 (50.2%) right-sided strokes. Median baseline NIHSS score was 17 (IQR 15-20). Good outcome at 90 days was achieved in 32.5%. For predicting good outcome, the c-statistic was significantly higher for m-TICI (0.74 vs. 0.68; p<0.0001). The threshold that maximized predictive accuracy was m-TICI ≥2B (sensitivity 78%, specificity 65%; figure). Conclusions: The modified TICI scale is superior to the TIMI scale for predicting clinical outcome after IAT, and should be the standard tool for grading angiographic reperfusion. An m-TICI score ≥2B (≥50% reperfusion) is the optimal biomarker for successful reperfusion.

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.