To determine the optimal cut-off time to intraarterial therapy (IAT) when considering outcomes.

IAT is standard of care for acute ischemic stroke management. All patients with suspected stroke receive imaging to assess IAT needs. Only patients with neuroimaging suggesting large vessel occlusion (LVO) are considered for treatment. Previous studies have examined IAT outcomes within 24 hours of symptom onset; at our center all LVOs are considered regardless of time.

This retrospective study included patients (age ≥ 18) admitted from 10/18-03/19 with an ischemic stroke treated by IAT. The primary outcome was discharge modified Rankin scale (mRS); secondary outcomes were IAT procedural complications, recanalization, and reperfusion injury. Time to IAT was defined as symptom onset to groin puncture. The receiver operating characteristic area under the curve (AUC) was used to determine the optimal cut-off times. Alpha=0.05.

There were 88 patients. The mean age was 67 years, 53% were male, and the median NIHSS was 14. Thirty percent (27) of patients received tPA. A majority of patients, 86% (62), went to IAT within 12 hours of symptom onset. Fifty-eight percent (50) had a discharge mRS of 3-6 and 28% (25) had a reperfusion injury. The models identifying a cut-off time to IAT for procedural complications and recanalization showed poor goodness of fit. The cut-off time to IAT for predicting a favorable discharge mRS was 6.8 hours and was strongly associated after adjustment, p<0.0001. There was moderate goodness of fit for reperfusion injury, with an associated cut-off time to IAT of 8.2 hours, p=0.01.

Reaching IAT within 6.8 hours of symptom onset may increase the probability of a favorable discharge mRS. In our population, reaching IAT within 8.2 hours was moderately associated with decreased probability of reperfusion injury.