Abstract
BACKGROUND: Effective collateral circulation significantly influences clinical outcomes in patients with acute ischemic stroke due to large vessel occlusion. We developed and evaluated a composite Perfusion Collateral Impairment Score (PCIS), combining the unfavorable dichotomizations of computed tomography perfusion-derived parameters (hypoperfusion intensity ratio, cerebral blood volume index, and prolonged venous transit), hypothesizing that higher scores, representing worse collateral status, are associated with poor functional outcomes at 90 days.
METHODS: In this multicenter retrospective study, we analyzed 224 patients with acute ischemic stroke due to large vessel occlusion presenting within 24 hours of symptom onset who underwent diagnostic computed tomography perfusion imaging. PCIS was calculated (range 0-3) based on unfavorable values of hypoperfusion intensity ratio (≥0.4), cerebral blood volume index (<0.8), and presence of prolonged venous transit, where each unfavorable parameter is allotted 1 point when present. The primary outcome was 90-day modified Rankin Scale score, categorized as favorable (0-2) and unfavorable (3-6).
RESULTS: Higher PCIS was associated with significantly worse outcomes. The proportion of patients with favorable 90-day outcomes (modified Rankin Scale 0-2) declined from 62% with PCIS 0 to 23% with PCIS 3 (P = 0.001). Multivariable analysis demonstrated that each 1-point increase in PCIS was independently associated with reduced odds of functional independence (adjusted odds ratio [OR], 0.60; 95% CI, 0.39-0.90; P = 0.015). Predicted probabilities of unfavorable outcome (modified Rankin Scale score 3-6) ranged from 38.2% (95% CI, 26.7-49.8) in PCIS 0 to 77.3% (95% CI, 59.8-94.8) in PCIS 3. The association between PCIS and outcomes persisted across treatment groups.
CONCLUSIONS: The PCIS, integrating 3 perfusion-based collateral parameters, is associated with 90-day functional outcomes in patients with acute ischemic stroke due to large vessel occlusion. This scoring system offers a prognostic tool to identify patients at higher risk for poor outcomes and may be useful for optimizing resource allocation. Prospective validation is warranted.