Computed Tomography Perfusion After Thrombectomy

Abstract

Background and Purpose— Despite recanalization, almost 50% of patients undergoing endovascular treatment (EVT) experience poor outcome. We aim to evaluate the value of computed tomography perfusion as immediate outcome predictor postendovascular treatment. Methods— Consecutive patients receiving endovascular treatment who achieved recanalization (modified Thrombolysis in Cerebral Ischemia [mTICI] 2a-3) underwent computed tomography perfusion within 30 minutes from recanalization (CTPpost). Hypoperfusion was defined as the Tmax>6 second volume; hyperperfusion as visually increased cerebral blood flow/cerebral blood volume with reduced Tmax compared with unaffected hemisphere. Dramatic clinical recovery (DCR) was defined as 24-hour National Institutes of Health Stroke Scale score ≤2 or ≥8 points drop. Delayed recovery was defined as no-DCR with favorable outcome (modified Rankin Scale score 0–2) at 3 months. Results— We included 151 patients: median National Institutes of Health Stroke Scale score 16 (interquartile range, 10–21), median admission ASPECTS 9 (interquartile range, 8–10). Final recanalization was the following: mTICI2a 11 (7.3%), mTICI2b 46 (30.5%), and mTICI3 94 (62.3%). On CTPpost, 80 (52.9%) patients showed hypoperfusion (median Tmax>6 seconds: 4 cc [0–25]) and 32 (21.2%) hyperperfusion. There was an association between final TICI and CTPpost hypoperfusion(median Tmax>6: 91 [56–117], 15 [0–37.5], and 0 [0–7] cc, for mTICI 2a, 2b, and 3, respectively, P <0.01). Smaller hypoperfusion volumes on CTPpost were observed in patients with DCR (0 cc [0–13] versus non-DCR 8 cc [0–56]; P <0.01) or favorable outcome (modified Rankin Scale score 0–2: 0 cc [0–13] versus 7 [0–56] cc; P <0.01). No associations were detected with hyperperfusion pattern. An hypoperfusion volume <3.5 cc emerged as independent predictor of DCR (OR, 4.1 [95% CI, 2.0–8.3]; P <0.01) and 3 months favorable outcome (OR, 3.5 [95% CI, 1.6–7.8]; P <0.01). Conclusions— Hypoperfusion on CTPpost constitutes an immediate accurate surrogate marker of success after endovascular treatment and identifies those patients with delayed recovery and favorable outcome.