Unrecognised obstructive sleep apnoea is common in severe peripheral arterial disease

Patients needing surgery for peripheral arterial disease (PAD) represent a severe form of atherosclerosis with an overall 5-yr mortality of 30% after revascularisation. The aetiology for poor post-operative clinical outcome in these high-risk patients is not fully established. Obstructive sleep apnoea (OSA) is associated with atherosclerosis and is an independent risk factor for fatal and nonfatal cardiac events. Here, we determine the prevalence of undiagnosed OSA in a homogenous group of PAD patients undergoing subinguinal surgical revascularisation. 82 consecutive patients (mean age 67 +/- 9 yrs, 52 males) with sinus rhythm and without congestive heart failure or previously diagnosed OSA were enrolled for pre-operative polysomnography and echocardiography. OSA was present in 70 (85%) patients (95% CI 75-93%), of whom 24 (34%) had severe OSA. OSA was mostly asymptomatic, and age- and sex-adjusted multivariate regression analysis showed no relation to obesity, metabolic syndrome or any manifestation of atherosclerosis, other than PAD. Left ventricular ejection fraction (p=0.002) and high-density lipoprotein/total cholesterol ratio (p=0.03) were the only independent predictors for the severity of OSA. Thus, prevalence of OSA is unexpectedly high in patients with PAD and is not related to classical risk factors of sleep apnoea.