Abstract WMP74: Perfusion Delay Volume Predicts 90-day Recurrence In Symptomatic Anterior Circulation Intracranial Stenosis: A Two-center Study

Abstract

Background: Intracranial arterial stenosis (ICAS) can cause stroke by different mechanisms: perforator disease, artery to artery embolism, and impaired flow. There is limited data exists on the utility of perfusion imaging in patients with ICAS. We aim to determine associations between perfusion delay volume and 90-day recurrence in patients with anterior circulation ICAS. Methods: This is a two-center study of symptomatic anterior circulation ICAS involving the left M1 or ICA who underwent perfusion imaging (MRP or CTP). The primary predictor was hypoperfusion mismatch volume HPV (T max delay volume - core volume) using Tmax>4 sec or Tmax>6 sec thresholds. The outcome was recurrent cerebrovascular events (RCVE) defined as new or worsening neurological symptoms due to confirmed or suspected new infarct or infarct extension. We used Youden’s index to define the optimal cut-point of Tmax4 and Tmax6 mismatch for predicting recurrent stroke. We fit time-to-event models for RCVE with HPV at dichotomized cut-points, both as a univariate analysis and after adjusting for co-variates. Results: 50 patients met the inclusion criteria and 30% had RCVE. The median T max 4 HPV in mL was higher in patients with vs. without RCVE (121 vs. 19, p < 0.001) and the median T max 6 HPV in mL was higher in patients with vs. without RCVE (33 vs. 0, p = 0.004). We found an association between Tmax> 4 sec hypoperfusion volume (AUC 0.79, p =0.012) and max>6 sec hypoperfusion volume (AUC 0.75, p = 0.008) with RCVE. For Tmax 4 the cut-point was at 94 mL and for Tmax6 the cut-point was at 10 mL. Recurrent stroke was higher in those with vs. without Tmax>4 sec ≥94 mL delay (66.7% vs. 14.3%, (p<0.001) and with vs. without Tmax>6 sec≥10 mL delay (68.8% vs. 11.8%, p<0.001). In separate adjusted Cox regression analyses, the adjusted hazard of Tmax>4 sec HPV ≥ 94 mL was 5.0 (95% CI 1.5-16.4) and that of Tmax>6 sec HPV > 8 ml was 11.3 (95% CI 3.7-116.8). Conclusion: In this two-center study, hypoperfusion delay volume is associated with early recurrence in patients with symptomatic ICAS. Studies are needed to validate our findings and to test endovascular reperfusion in the subset of patients with symptomatic ICAS and perfusion delay.