P002 Relationship between OSA and Thoracic Aortic Dimensions

Abstract Introduction Obstructive sleep apnoea (OSA) is highly prevalent and is associated with a range of cardiovascular diseases. An association between OSA and aortic aneurysms has been reported. This is thought to be a multifactorial association, but exaggerated intrathoracic pressure swings occurring during obstructed breathing events in OSA have been implicated. This study aimed to assess the association of the presence and severity of OSA and thoracic aortic dimensions. Methods This is a retrospective observational study utilising a clinical database. Patients were included if they had undergone transthoracic echocardiography in the six months prior to a diagnostic sleep study. They were divided into two groups: either no or mild OSA (apnoea-hypopnoea index (AHI) ≤15/hr), and moderate-to-severe OSA (AHI>15/hr). Echocardiography measures included aortic root diameter in millimetres and indexed to body surface area (mm/m2). Results The study included 1470 patients (56% male, mean±SD age 63±14 years, body mass index 30±6kg/m2). Compared to patients with no or mild OSA (n=558, 38%), patients with moderate-to-severe OSA (n=1545, 62%) had larger absolute aortic root dimensions (35.0±4.1 versus 33.0±4.2mm, p<0.0001), after correction for body surface area aortic root dimensions were similar between groups (1.7±0.2 versus 1.7±0.2mm, p=0.6122). Among patients with any OSA (AHI>5/hr, n=1329, 90%) there was a weak correlation between aortic diameter and AHI (r=0.23, p<0.0001). Conclusions More severe OSA is associated with increased absolute thoracic aorta dimensions. The clinical relevance of these findings remains to be determined.