Hypoperfusion Intensity Ratio is Correlated With the Risk of Futile Reperfusion After Endovascular Treatment

Half of ischemic stroke patients are subject to futile reperfusion (FR) after endovascular treatment (EVT). The hypoperfusion intensity ratio (HIR) represents tissue-level collaterals (TLC). We aimed to evaluate the predictive performance of HIR in the assessment of FR.

Retrospective data were derived from a multicenter cohort study of patients with large vessel occlusion in the anterior circulation who underwent EVT in China. HIR was automatically calculated on baseline perfusion imaging as the ratio of brain volume with Tmax >10 s over volume with Tmax >6 s. Poor TLC was regarded as HIR >0.4. The primary outcome was FR, defined as modified Rankin Scale score of 4-6 at 90 days despite successful recanalization. Safety outcomes were symptomatic intracranial hemorrhage (sICH) within 36 h and all-cause mortality at 90 days.

A total of 910 patients were included, and we observed FR in 325 (35.7%) patients after EVT. More frequent FR at 90 days was seen in patients with poor TLC (50.2% vs. 30.1%; odds ratio [OR], 2.34; 95% confidential interval [CI], 1.74-3.25; P<0.001). In multivariable regression, the higher HIR was independently associated with higher odds of FR (adjusted OR, 1.88; 95% CI, 1.31-2.68; P=0.001). The rates of sICH were not significantly different between the two groups. HIR>0.4 was correlated with higher rates of 90-day mortality even after adjusting covariates.

Poorer HIR on admission perfusion imaging was strongly associated with FR occurrence after EVT. This automated and rapidly available perfusion parameter might help the identification of stroke patients at risk of FR.