Low ABI as an independent risk factor for stroke recurrence and further vascular events

Hong JB, Leonards CO, Endres M, et al.
Stroke. 2016;47:317-322

Background

The risk of stroke recurrence is high, especially within the first few months after the index event [1]. Patients with transient ischemic attack (TIA) are at high risk of stroke as well, particularly in the first 48 hours after the initial event [2].
Several management strategies are available to reduce the risk of stroke recurrence in high-risk patients, like for example, aggressive treatment of concurrent vascular risk factors or encouragement of patient adherence. Yet, it seems that there is room for improvement regarding secondary prevention strategies, given that stroke patients with peripheral artery disease (PAD) are treated less frequently with statins and antiplatelet therapy, than coronary artery disease patients with PAD [3].
To reduce the risk of recurrent stroke in high-risk patients, efficient risk prediction models are necessary. The ankle-brachial index (ABI) might be a useful tool to this direction.
ABI reflects the ratio between systolic blood pressures measured at the ankle and arm of a patient in the supine position, thus detecting arterial stenosis in the lower extremities, and is widely used for the diagnosis of PAD [4].
The present systematic review and meta-analysis evaluates the relationship between decreased ankle-brachial index (ABI) and increased recurrent stroke risk or vascular risk, in 11 studies including 5374 patients. Vascular risk assessment was based on recurrent vascular events or vascular death.

Main results

• The risks of combined vascular events and stroke recurrence per year of follow-up ranged from

• 7.1% to 33.3% and 3.1% to 21.4% for the low-ABI group
• 3.8% to 14.1% and 3.1% to 9.7% for the normal ABI group

• Pooling of relative risks

• for recurrent stroke resulted in an overall RR of 1.55 (95% CI: 1.28–1.88)
• for the combined vascular end point yielded an overall RR of 1.91 (95% CI: 1.65–2.22)

• Low ABI was associated with

• an increased hazard of recurrent stroke (HR: 1.70; 95% CI: 1.10–2.64)
• an increased risk of vascular events or vascular death (HR: 2.22; 95% CI: 1.67–2.97)

Conclusion

These data support the hypothesis according to which low ABI measurements indicate a high risk for recurrent stroke or vascular events, although the risk estimates are more conservative than previous reports. Further studies are needed to examine whether the inclusion of ABI in existing risk prediction models improves their predictive accuracy.

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References

1. Mohan KM, Wolfe CD, Rudd AG, et al. Risk and cumulative risk of stroke recurrence: a systematic review and meta-analysis. Stroke. 2011;42:1489–1494
2. Wu CM, McLaughlin K, Lorenzetti DL, et al. Early risk of stroke after transient ischemic attack: a systematic review and meta-analysis. Arch Intern Med. 2007;167:2417–2422
3. Banerjee A, Fowkes FG, Rothwell PM. Associations between peripheral artery disease and ischemic stroke: implications for primary and secondary prevention. Stroke. 2010;41:2102–2107
4. Dachun Xu, Jue Li, Liling Zou, et al. Sensitivity and specificity of the ankle–brachial index to diagnose peripheral artery disease: a structured review. Vasc Med. 2010;15:361–369