Abstract

Introduction: Obstructive sleep apnea (OSA) is a known risk factor for cardiovascular mortality and morbidity. Patients with OSA can present with clinical syndromes of heart failure, but most of them have preserved left ventricular ejection fraction (HFpEF). In Malaysia, data regarding left ventricular (LV) diastolic dysfunction among OSA patients is limited. 

Objective: To determine the prevalence of LV diastolic dysfunction and factors associated with LV diastolic dysfunction among OSA patients on positive airway pressure (PAP) treatment.

Method:  Cross-sectional study analyzing 47 patients with OSA on PAP treatment at Sarawak General Hospital. All patients underwent transthoracic echocardiography (TTE) and serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) level was measured. 

Results: The mean age was 52.2±14.24 years, mean body mass index (BMI) 39.80±89.7 kg/m2, and mean apnea hypopnea index (AHI) 60.7±29.1. The mean LVEF was 66.2±8.0% and 15.6% had LV diastolic dysfunction. Most patients (14.9%) had grade II and 2.1% with grade III LV diastolic dysfunction. Among the patients with LV diastolic dysfunction, NT-proBNP was significantly elevated (>125pg/ml) in 87.5% of patients (p<0.001). Elevated NT-proBNP level of >125pg/ml had positive predictive value, negative predictive value, sensitivity and specificity of 70%, 97.3%, 87.5% and 92.3% respectively to diagnose LV diastolic dysfunction.

Conclusion: The prevalence of LV diastolic dysnfunction in OSA patients was 15.6%. Elevated NT-proBNP level (>125 pg/ml) was a useful biomarker in the diagnosis of LV diastolic dysfunction among OSA patients.