Citing a need for improved recurrent stroke risk prediction, the authors of this systematic review and meta-analysis explore the association between low ankle-brachial index (ABI) and recurrent stroke risk.

The meta-analysis included only prospective trials that collected at least 12 months of follow-up data regarding recurrent stroke, vascular events and/or vascular death. In pooling the data, their primary endpoints were recurrent stroke and combined vascular events (recurrent vascular event and vascular death). Ischemic stroke and TIA were variably included as outcomes. 

Ultimately, 11 studies with 5,374 participants were included in the meta-analysis. Pooled analysis of relative risks of recurrent stroke and combined vascular endpoint in patients with low ABI were 1.55 (95% CI, 1.28-1.88) and 1.91 (95% CI, 1.65-2.22), respectively.

There was heterogeneity among the studies in terms of covariates entered into individual multivariate models; this limits precise estimation of the association between ABI and recurrent stroke risk. Publication bias was also present, which also limits our ability to draw confident conclusions.

The authors conclude that there is a robust association between low ABI and recurrent stroke and vascular outcome risk.

The bottom line
Even if ABI indeed predicts recurrent stroke independent of traditional vascular risk factors, existing data do not allow us to conclude that ABI measurement provides recurrent stroke predictive value in excess of that provided by advanced standard-of-care stroke diagnostics. Ideal recurrent stroke risk prediction models will incorporate data collected for standard stroke evaluation and will therefore be parsimonious and cost-effective.