Pittsburgh response to endovascular therapy score as a pre-treatment prognostic tool: External validation in Trevo2

Background Optimal patient selection is needed to maximize the therapeutic benefit of endovascular therapy for large vessel occlusion stroke. Aims To validate the Pittsburgh response to endovascular therapy (PRE) score in a randomized controlled trial (Trevo2) comparing stent retriever (Trevo) to the Merci device. Methods Trevo2 participants with internal carotid, M1 and M2 middle cerebral artery occlusions with prospectively collected baseline stroke severity (NIHSS), degree of hypodensity (CT ASPECTS), and three-month modified Rankin Scale (mRS) were included. Multivariable regression was used to confirm association between PRE score variables (age, NIHSS, and ASPECTS), medical comorbidities, randomization arm, and reperfusion status (mTICI2B/3) with good outcome (three-month modified Rankin Scale 0-2). Predictive power (area under the receiver operating characteristic curve) for good outcome of pre-treatment prognostic scores (PRE, THRIVE, HIAT2) was compared. Rates of good outcome were compared between successfully reperfused (mTICI2B/3) and non-reperfused (mTICI0-2A) patients across previously identified PRE score risk groups. Results Age, NIHSS, ASPECTS, reperfusion status, and randomization arm were independent predictors of good outcome. PRE score had moderate predictive power (AUC = 0.75) for good outcome and was comparable to other pre-treatment scores. Reperfusion resulted in maximal treatment benefit in patients with PRE score 0-24 (60% vs. 12.5%, p = 0.002) but not in those with PRE ≥50 (11.8% vs. 0.0%, p = 0.49). Conclusion The PRE score is a validated predictor of functional outcome and a tool for patient selection for endovascular therapy in anterior large vessel occlusion stroke. Our finding of limited benefit of reperfusion in patients with PRE score ≥50 needs to be prospectively validated.