Severity of obstructive sleep apnea and extension of coronary artery disease

Obstructive sleep apnea (OSA) is highly prevalent among patients with coronary artery disease (CAD). The relationship between the severity of OSA and the severity of CAD has not been entirely established. The objective was to explore the type of correlation existent between the apnea-hypopnea index and the Gensini score, which provides granularity in terms of CAD extension and severity, in search of a dose-response relationship.

A cross-sectional study was conducted among patients that underwent cardiac catheterization due to the suspicion of CAD. Coronary lesions were classified according to one's Gensini score. The severity of OSA was determined by the apnea-hypopnea index (AHI), obtainable through a respiratory polysomnography.

Eighty patients were eligible for the study. The mean age was 55 years, and 37% had AHI ≥ 15. Forty-four subjects (55%) had a Gensini score of 0, and five had a score < 2, indicating a 25% obstruction in a non-proximal artery; these individuals were considered non-CAD controls; and clinical characteristics were similar between them and CAD cases. Attempts to correlate the AHI with the Gensini score either converting both variables to square root (r = 0.08) or using Spearman's rho (rho = 0.13) obtained small, non-significant coefficients. AHI ≥ 15 was a predictor of a Gensini score ≥ 2 with a large effect size (OR 4.46) when adjusted for age ≥ 55 years, BMI ≥ 25 kg/m², uric acid, and hypertension.

In patients undergoing coronary angiography due to suspected CAD, moderate-severe OSA was associated with the presence of CAD but no significant correlation was found between the lesion severity and the AHI. Our results suggest that OSA influences CAD pathogenesis but a dose-response relationship is unlikely.