Comparative Study of Cardiac Structure and Function in Obstructive Sleep Apnea Patients Based on the Classification of Hypopnea/Apnea Ratio postprint

Abstract: Background  Obstructive sleep apnea (OSA) is associated with cardiac structural remodeling and functional impairment. Most studies have focused on the overall OSA population, with limited attention given to the impact of different distributions of hypopnea and apnea events on cardiac structure and function. Objective  To compare the impact of different hypopnea/ apnea ratio (HAR) classifications on cardiac structure and function in patients with OSA. Methods  A retrospective analysis was conducted on 193 hospitalized patients with OSA and 44 control subjects at the Department of General Practice, Daping Hospital, Army Medical University from January 2023 to February 2025. All participants underwent comprehensive echocardiography during the same period. Based on the HAR, OSA patients were classified into apnea-dominant (n=66) and hypopnea-dominant (n=127) groups. They were also divided into mild (n=68), moderate (n=73), and severe (n=52) OSA groups according to the apnea hypopnea index (AHI). General demographics, comorbidities, biochemical indicators, sleep monitor parameters, and echocardiography data were collected to analyze the impact of different HAR classifications on cardiac structure and function in patients with OSA. Results  Left atrial systolic diameter (LADs), left ventricular diastolic diameter (LVDd), right atrial systolic diameter (RADs), aortic sinus diameter (AOAs), main pulmonary artery systolic diameter (MPAs), interventricular septum diastolic thickness (IVSTd), and left ventricular posterior wall diastolic thickness (LVPWd) were significantly higher in apneadominant OSA patients than those in hypopnea-dominant patients(P<0.05). Spearman correlation analysis revealed that in patients with OSA, LADs, LVDd, RADs, AOAs, MPAs, IVSTd, and LVPWd were positively correlated with AHI, obstructive apnea index (OAI), and oxygen desaturation index (ODI), while negatively correlated with HAR. The hypopnea index (HI) was positively correlated with MPAs, and the lowest SpO2 (LSpO2) was negatively correlated with MPAs. The percentage of total sleep time with SpO2 <90% (T90) was positively correlated with LADs, LVDd, RADs, AOAs, and MPAs (P<0.05). Multiple linear regression analysis revealed that after adjusting for the effects of gender, age, BMI, and AHI, there were no significant differences in cardiac structural indicators between the two types of OSA. Gender, age, and BMI were significant predictors of multiple cardiac structural parameters (P < 0.05), while AHI was identified as an independent predictor of MPAs (P<0.05). Conclusion  The distribution patterns of hypopnea and apnea events show no difference in their impact on cardiac structure and function in OSA patients. Gender, age, BMI, and AHI may have more significant impacts on cardiac remodeling.