Association of C1q/TNF-Related Protein-9 (CTRP9) Level with Obstructive Sleep Apnea in Patients with Coronary Artery Disease

Background. Obstructive sleep apnea (OSA) is closely related to the incidence and progression of coronary artery disease (CAD), and the mechanisms linking OSA and CAD are multifactorial. C1q/TNF-related protein-9 (CTRP9) is a novel adipokine that protects the heart against ischemic injury and ameliorates cardiac remodeling. We aimed to ascertain the clinical relevance of CTRP9 with OSA prevalence in patients with CAD. Methods. From August 2016 to March 2019, consecutive eligible patients with CAD (n=154; angina pectoris, n=88; acute myocardial infarction [AMI], n=66) underwent cardiorespiratory polygraphy. OSA was defined as an apnea-hypopnea index (AHI) ≥15 events·h⁻¹. Plasma CTRP9 concentrations were measured by ELISA method. Results. Moderate/severe OSA was present in 89 patients (57.8%). CTRP9 levels were significantly decreased in the moderate/severe OSA group than in the no/mild OSA group (4.7 [4.1-5.2] ng/mL vs. 4.9 [4.4-6.0] ng/mL, P=0.003). The difference between groups was only observed in patients with AMI (3.0 [2.3-4.9] vs. 4.5 [3.2-7.9], P=0.009). Correlation analysis showed that CTRP9 levels were negatively correlated with AHI (r=−0.238, P=0.003) and oxygen desaturation index (r=−0.234, P=0.004) and positively correlated with left ventricular ejection fraction (r=0.251, P=0.004) in all subjects. Multivariate analysis showed that male gender (OR 3.099, 95% CI 1.029-9.330, P=0.044), BMI (OR 1.148, 95% CI 1.040-1.268, P=0.006), and CTRP9 levels (OR 0.726, 95% CI 0.592-0.890, P=0.002) were independently associated with the prevalence of moderate/severe OSA. Conclusions. Plasma CTRP9 levels were independently related to the prevalence of moderate/severe OSA in patients with CAD, suggesting that CTRP9 might play a role in the pathogenesis of CAD exacerbated by OSA.