Introduction: Recent trial data demonstrating the benefit of endovascular therapy (EVT) in conjunction with chemical thrombectomy for acute ischemic stroke (AIS) patients has led to increased referrals to comprehensive stroke centers for consideration of EVT. We aimed to characterize the baseline predictors and patterns of transfer for patients undergoing EVT.
Methods: Baseline demographics, vascular risk factors (age, diabetes, hypertension, history of coronary or carotid disease, atrial fibrillation, anticoagulation use, prior history of stroke/TIA), NIHSS scores, ASPECTS, time from symptom onset to CT and to tPA infusion, transfer time and presence of large vessel occlusion between patients who underwent EVT versus those who did not upon transfer, were recorded from Feb - July 2015 for AIS patients at a single institution.
Results: Forty-three AIS patients were transferred to our institution within 6h of stroke onset and after treatment with IV tPA at outside hospitals for potential EVT; (age: 30-101, 42% women, 44% underwent EVT). In comparison to patients treated medically, those who underwent EVT had a greater frequency of proximal arterial occlusion (95% vs. 38%, p<0.001) and higher baseline NIHSS scores (mean: 17 vs. 9, p<0.001). Although not statistically significant, the EVT group was younger (62 vs. 71 years) and had shorter transfer times (161 vs. 135 min). NIHSS (OR 1.2, 95% CI 1.0-1.5), but not proximal vessel occlusion (OR 6.5, 95% CI 0.5-81.9), independently predicted those who underwent EVT in a multivariable regression analysis. NIHSS was highly discriminatory for individuals undergoing EVT (area under the receiver operating characteristic curve: 0.9, p<0.001), with a NIHSS threshold of 9 having a negative predictive value of 100% and positive predictive value of 66%.
Conclusions: In this single center study; NIHSS was the only independent predictor of EVT in patients transferred within 6 hours of symptom onset presenting with acute ischemic stroke.
Patient Care: A number of studies have indicated that time from symptom onset to recanalization is directly correlated with improved functional outcomes in patients presenting with acute ischemic stroke. However, significant time delays still exist within this framework. Understanding the factors which can be used to discriminate between patients eligible for endovascular therapy and those who are not, is essential to enabling the efficient and rapid transport of these patients to stroke centers capable of performing mechanical thrombectomy.
Learning Objectives: By the conclusion of this session, participants should be able to (1) recognize that NIHSS scores can serve as predictors for transfer for mechanical thrombectomy for patients presenting with acute ischemic stroke and (2) discuss ways by which transfer times for these patients can be reduced, thereby enabling rapid transport to comprehensive stroke centers following symptom onset.