Obstructive sleep apnoea in patients with abdominal aortic aneurysms: highly prevalent and associated with aneurysm expansion

Abstract

RATIONALE: Abdominal aortic aneurysms (AAA) are associated with life-threatening complications. The likelihood that an AAA will rupture is influenced by the aneurysm diameter and its expansion rate; reasons for rapid expansion are largely unknown. OBJECTIVES: To determine the prevalence of obstructive sleep apnea (OSA) in patients with AAA, and investigate a possible association between OSA and rate of AAA expansion. METHODS: 127 patients (11 females), included in an AAA surveillance program, agreed to participate and underwent a sleep study. Annual AAA expansion was determined retrospectively from available ultrasound measurements. OSA was characterised using both oxygen desaturation index (ODI) and apnea-hypopnea index (AHI). Univariate and multivariate analysis was performed to assess the effect of OSA severity on AAA expansion. MEASUREMENTS AND MAIN RESULTS: Mean age, 67.9 (SD 6.0) years. Median interval between the first and last AAA measurements, 18.0 (range 2-113) months. An ODI or AHI of >10 was found in 40.5% and 41.5% of the patients respectively. Patients with an ODI>30 (n=12) had a significantly faster median yearly AAA expansion rate (2.9, quartiles 2.0/5.7 mm/y) than patients with an ODI 0-5 (n=47, 1.2, quartiles 0/3.1 mm/y) or 6-15 (n=43, 1.3, quartiles 0/2.7 mm/y) (p<0.05). In multivariate regression analysis, controlling for cardiovascular risk factors and medications, ODI >30 remained an independent risk factor for AAA expansion. CONCLUSIONS: In patients with AAA, OSA is highly prevalent. Severe OSA may be a causal factor for faster AAA expansion, but this needs to be proven in a randomized controlled intervention trial.