Abstract W P55: The Degree of Cerebral Blood Flow Augmentation by External Counterpulsation Correlates With Clinical Outcome After Acute Ischemic Stroke

Background and Purpose: External counterpulsation (ECP) is a novel noninvasive method used to augment cerebral blood flow which may benefit ischemic stroke patients. We aimed to explore the association between the degree of cerebral blood flow augmentation by ECP and clinical outcome after acute ischemic stroke. Methods: Acute ischemic stroke patients within 7 days of symptom onset were recruited into this study. On admission, bilateral middle cerebral arteries of subjects were monitored using transcranial Doppler (TCD). Flow velocity changes before, during, and after ECP were, respectively, recorded for 3 minutes. Cerebral augmentation index (CAI) was the increase in percentage of middle cerebral artery mean flow velocity during ECP compared with baseline. TCD data were analyzed based on ipsilateral or contralateral to the infarct side. Modified Rankin Scale (mRS) was evaluated 3 months, 6 months and 1 year after ischemic stroke onset. We stratified the patients into two groups (good outcome: mRS 0~2; poor outcome: mRS 3~6) at each measurement time point. Results: 72 patients were recruited (mean age, 63.8±10.7 years; 87.5% males). At month 6 and year 1 after stroke onset, univariate analysis showed that admission National Institutes of Health Stroke Scale (NIHSS) was significantly lower and ECP therapy duration was longer in good outcome group; while the ipsilateral CAI was significantly lower in good outcome group than those in poor outcome group (3.71±4.94 versus 7.73±7.66, P=0.044; 3.50±4.73 versus 8.58±7.72, P=0.015 respectively). Multivariate logistic regression showed that ipsilateral CAI and baseline NIHSS were independent predictors for a favourable outcome at these two measurement points. Conclusions: The degree of cerebral augmentation on ipsilateral to the infarct side by ECP is found to be an important predictor for long-term good outcome in acute ischemic stroke patients, in addition to the well-known prognostic factors such as NIHSS.