Use of the augmentation index to predict short-term outcome after acute ischemic stroke

BACKGROUND: Simple, noninvasive measures of arterial disease may help to predict outcome after stroke. This observational study examined the relationship between measures of arterial function obtained from pulse wave analysis (PWA), stroke type, and in-hospital outcome after ischemic stroke.

METHODS: The admission augmentation index (AIx) and computed central pulse pressure (CPP) in 60 volunteers admitted with acute ischemic stroke were assessed for associations with length of stay in hospital and with Barthel index at admission, 1 week poststroke, and at discharge. Stroke types were classified by the Bamford and trial of ORG 10172 in acute stroke treatment (TOAST) criteria.

RESULTS: Spearman rank correlation (r) between AIx at admission and length of stay was 0.40 (P = 0.006). AIx was significantly correlated with Barthel index at 1 week (r = -0.30, P = 0.03) and at discharge (r = -0.35, P = 0.009) but not at admission (r = -0.02, P = 0.88). AIx remained an independent predictor of both Barthel index at discharge and length of stay on multivariate regression analysis. There were no statistically significant correlations between CPP and any outcome measure. No significant differences in AIx were found between stroke subtypes using analysis of variance, although post hoc subset analysis showed strokes due to large-artery disease had higher AIx.

CONCLUSIONS: AIx was correlated with increased length of stay and Barthel index a week after stroke and at discharge. Its clinical utility as a predictor of outcome after stroke merits further investigation.