Peripheral Arterial Disease, Stroke, and Mortality in Patients with Atrial Fibrillation

Abstract

I read the paper by Vitalis et al1Vitalis A Shantsila A Proietti M et al.Peripheral arterial disease in patients with atrial fibrillation: the AFFIRM Study.Am J Med. 2021; 134: 514-518Abstract Full Text Full Text PDF Scopus (8) Google Scholar with great interest. The authors assessed the impact of peripheral arterial disease on mortality and stroke in patients with atrial fibrillation. The adjusted hazard ratio (HR) (95% confidence interval [CI]) of peripheral arterial disease in patients with atrial fibrillation for all-cause mortality was 1.34 (1.06-1.70). In addition, the adjusted HR (95% CI) of peripheral arterial disease in patients with nonanticoagulated atrial fibrillation for ischemic stroke was 3.37 (1.25-9.09). Peripheral arterial disease and atrial fibrillation share common risk factors. I have 2 comments about their study with causal directions. First, Vrsalović et al2Vrsalović M Presečki AV. Atrial fibrillation and risk of cardiovascular events and mortality in patients with symptomatic peripheral artery disease: a meta-analysis of prospective studies.Clin Cardiol. 2017; 40: 1231-1235Crossref PubMed Scopus (16) Google Scholar conducted a meta-analysis to evaluate the association of atrial fibrillation with major adverse cardiac events (MACE) and mortality in patients with peripheral arterial disease. The pooled odds ratios (95% CIs) of atrial fibrillation for mortality and MACE were 2.52 (1.91-3.34) and 2.54 (1.78-3.63), respectively. I suppose that synergic effects with peripheral arterial disease and atrial fibrillation for MACE and mortality might have existed, and selecting appropriate statistical model is important for the analysis. In any case, atrial fibrillation and peripheral arterial disease are significant contributors for vascular events. Second, Tseng et al3Tseng AS Girardo M Firth C et al.Lower extremity arterial disease as a predictor of incident atrial fibrillation and cardiovascular events.Mayo Clin Proc. 2021; 96: 1175-1183Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar evaluated the relationship between peripheral arterial disease and incident atrial fibrillation with special reference to ischemic stroke and all-cause mortality. The adjusted HR (95% CI) of low ankle-brachial index (ABI) (<1.0) and elevated ABI (≥1.4) for incident atrial fibrillation were 1.14 (1.06-1.22) and 1.18 (1.06-1.31), respectively. In addition, there was a dose-dependent relationship between severity of peripheral arterial disease and incident atrial fibrillation. They concluded that patients with peripheral arterial disease had an increased risk of ischemic stroke and all-cause mortality, which was consistent with data by Vitalis et al. As they pointed out, monitoring ABI may be useful to prevent clinical events. From the viewpoint of prevention, tobacco smoking is a major risk factor for atrial fibrillation, peripheral arterial disease, and cardiovascular disease events.4Klein A Shenasa M Baranchuk A. Social risk factors and atrial fibrillation.Card Electrophysiol Clin. 2021; 13: 165-172Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar I think that interaction analysis with causal direction may be important for the risk assessment.