Lanxin Feng,1 Xin Zhao,1 Jianqiao Song,2 Shuwen Yang,1 Jianping Xiang,3 Min Zhang,1 Chenchen Tu,1 Xiantao Song1 

1Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, People’s Republic of China; 2Sun Yat Sen University, Zhongshan School of Medicine, Guangzhou, People’s Republic of China; 3ArteryFlow Technology Co., Ltd., Hangzhou, People’s Republic of China

Correspondence: Chenchen Tu, Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, People’s Republic of China, Email tcc2033@163.com

Objective: There is a connection between obstructive sleep apnea (OSA) and coronary microvascular dysfunction (CMD), but the underlying mechanisms remain unclear. This study aims to evaluate the correlation between OSA-related nocturnal hypoxemia parameters and CMD.
Methods: This is an observational, single-center study that included patients who underwent polysomnography and coronary angiography during hospitalization. The presence of CMD was determined by angio-based index of microcirculatory resistance (AccuIMR). Categorical variables were compared using chi-square test or Fisher exact test. The t-test and Mann–Whitney U-test were used to compare normally and non-normally distributed continuous variables, respectively. Univariate and multivariable logistic regression analyses were performed to evaluate the relationship between nocturnal hypoxemia parameters and CMD.
Results: A total of 133 patients were included in this study, of whom 72 (54.14%) had evidence of CMD. Patients with CMD exhibited a higher prevalence of OSA and experienced more severe nocturnal hypoxia. After adjusting for potential confounding factors, minimum oxygen saturation (minSpO2) ≤ 90% (OR 5.89; 95% CI 1.73– 19.99; P=0.004) and the percentage of time spent with oxygen saturation below 90% (T90) ≥ 5% (OR 3.13; 95% CI 1.05– 9.38; P=0.041) were independently associated with CMD. However, no significant association was observed between apnea-hypopnea index (AHI) and CMD.
Conclusion: Parameters of nocturnal hypoxemia are associated with CMD. Hypoxemia parameters may more sensitively reflect the correlation between OSA and CMD than AHI.

Keywords: obstructive sleep apnea, coronary microvascular dysfunction, nocturnal hypoxemia, cardiology, dentistry