Abstract WP172: Using a Novel and Noninvasive Cerebral Augmentation Index as Evaluated by External Counterpulsation to Predict Long-term Clinical Outcome After Acute Ischemic Stroke

Abstract

Background and Objectives: External counterpulsation (ECP) is a non-invasive method used to augment cerebral blood flow of patients with ischaemic stroke via induced hypertension. We aimed to investigate whether the cerebral augmentation index (CAI) evaluated by ECP can predict clinical outcomes after acute ischemic stroke. Methods: We enrolled acute ischemic stroke patients within 7 days after stroke onset. Bilateral middle cerebral arteries of patients were monitored using transcranial Doppler (TCD). Flow velocity changes before, during and after ECP were, respectively, recorded for 3 mins. The cerebral augmentation index (CAI) was the increase in percentage of the middle cerebral artery mean flow velocity during ECP compared with baseline. TCD data were analysed based on the side ipsilateral or contralateral to the infarct. The modified Rankin Scale (mRS) (good outcome: mRS 0∼2; poor outcome: mRS 3∼6) was evaluated 3 months after the index stroke. Results: 200 patients were included (mean age, 64.5±8.9 years; 86.5% males). At month 3 after stroke onset, univariate analysis showed that the National Institutes of Health Stroke Scale at recruitment was significantly higher in the poor outcome group, while the bilateral CAIs were significantly lower in the good outcome group than those in the poor outcome group (ipsilateral 3.72±2.94 vs 7.92±6.25, p=0.032; contralateral 4.04±3.82 vs 6.98±6.05, p=0.048). Multivariate logistic regression showed that bilateral CAIs were independently correlated with an unfavorable functional outcome after adjusting for confounding factors. Conclusions: The higher degree of cerebral blood flow velocity augmentation on the both sides ipsilateral and contralateral to the infarct induced by ECP is independently correlated with an unfavorable functional outcome after acute ischemic stroke.