[Sleep-related breathing disorders in patients with coronary heart disease]

Abstract

Introduction and aim of study: Obstructive sleep apnoea (OSA) favours the development of arterial hypertension independently of body-weight and may thus have an effect on coronary heart disease (CHD). This study was undertaken to determine the prevalence of OSA in patients with CHD.

Patients and methods: From among all patients in whom left heart catheterization with coronary angiography had provided the diagnosis of coronary heart disease 50 were randomly chosen (47 men, 3 women; mean age 61 +/- 6 years) for further investigations. During the night airway flow, heart rate, body position and arterial oxygen saturation were recorded. The patients also had to fill in a questionnaire concerning tiredness during the day and any snoring. Polysomnography was performed in all those whose apnoea index (AI) was > 10/h.

Results: 25 patients had an apnoea index of > 10/h. Eight of them also had increased tiredness during the day. The patients with an AI > 10/h were significantly older than those in whom it was < or = 10/h (63.1 +/- 3.5 vs 58.4 +/- 7.2 years; P < 0.002) and also had a higher body-mass index (27.8 +/- 4.2 vs 25.7 +/- 3.0 kg/m2; P < 0.05). Polysomnography, done in the sleep laboratory, in 19 of the 25 patients with an AI > 10/h registered an average AI of 17.0 +/- 10.9 per hour sleep; in seven patients it was > 20/h.

Conclusions: The prevalence of obstructive sleep apnoea (OSA) is higher in patients with coronary heart disease (CHD) than in the healthy population. As OSA associated with a marked fall in nocturnal blood oxygen saturation and a rise in blood pressure may cause myocardial ischaemia, OSA should also always be considered when CHD is diagnosed.