The prognostic capacity of Sleep apnea-specific hypoxic burden on the incidence of cardiovascular events: A comparative study with tradicional polygraphic parameters in patients with Obstructive Sleep Apnea.

<bold>INTRODUCTION:</bold> Several retrospective studies, most population-based cohorts suggest that hypoxic burden (HB) presents a prognostic value for cardiovascular events (CVE) better than the classic apnea-hypopnea index (AHI) or oxygen desaturation index (ODI) in patients with obstructive sleep apnea (OSA). This study aims to compare, in the first real-life prospective study, the prognostic value of HB compared to clasic polygraphic parameters on the incidence CVE. <bold>METHODS:</bold> Prospective study of consecutive OSA patients. Sleep study was conducted by respiratory polygraphy with added HB measurement software, defining HB as the area under the desaturation curve (number, length, depth) related to respiratory events. Parameters (HB, AHI, ODI3%, Tsat90%) were divided into tertiles. The primary outcome was a composite of ischemic heart disease, stroke, pulmonary embolism, heart failure, AF, and hypertensive crisis (fatal/non-fatal). The prognostic capacity was assessed by Cox survival analysis. (HR, 95% CI). The minimum sample size for CVE was 80. Patients were followed until reaching required CVE sample size. <bold>RESULTS:</bold> From 825 initial patients, 533 were included. Over 15 months (IQR: 12-17), 84 CVE occurred (37 hypertensive crises, 15 heart failures, 12 ischemic heart diseases, 14 AF, 2 pulmonary embolisms, and 4 strokes). Prognostic capacity of polygraphic variables and corresponding Kaplan-Meier curves for HB and Tsat90% are shown in figures 1,2. <bold>Conclusion:</bold> Hypoxic burden and Tsat90% are better predictors than AHI and ODI3% for incident cardiovascular events in OSA patients.