Screening for obstructive sleep apnea in veterans with ischemic heart disease using a computer-based clinical decision-support system.

OBJECTIVES: To assess the validity of a handheld clinical decision-support system (CDSS) in detecting obstructive sleep apnea (OSA) in veterans with ischemic heart disease against polysomnography (PSG) and to compare the diagnostic accuracy of the CDSS versus the Berlin questionnaire. METHODS: We enrolled prospectively 143 patients with underlying ischemic heart disease. Veterans with history of neurologic disease, systolic congestive heart failure, or receiving opiates were excluded from participation. Participants were asked to complete the Berlin Questionnaire and to answer all eight questions of CDSS-software. At the end of the interview, veterans were scheduled for an in-laboratory polysomnogram. RESULTS: Ninety one patients completed the study. The prevalence of OSA (AHI ≥5/h) was 74.7 % with a median AHI of 11.5/h (range 0-90). When compared to PSG, the CDSS and the Berlin questionnaire achieved a sensitivity of 98.5 % [95 % confidence interval (CI) 92.1-100] and 80.9 % (95 % CI 69.5-89.4) and a specificity of 86.9 % (95 % CI 66.4-97.2) and 39.1 % (95 % CI 19.7-61.5) at a threshold value of AHI ≥5 with a corresponding area under the curve of 0.93 (95 % CI 0.85-0.97) and 0.60 (95 % CI 0.49-0.70); respectively. CONCLUSIONS: CDSS is a superior screening tool for identifying cardiac veterans with undiagnosed OSA than the BQ.

Lectin-like oxidized low-density lipoprotein receptor-1 modulates endothelial apoptosis in obstructive sleep apnea.

BACKGROUND: Lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) is the major receptor for oxidized low-density lipoprotein in endothelial cells, and its expression is enhanced in proatherogenic settings. The objective of this study was to investigate the association between LOX-1 in freshly harvested human venous endothelial cells and apoptotic circulating endothelial cells in patients with obstructive sleep apnea (OSA). METHODS: We conducted a prospective, interventional study of 38 patients with newly diagnosed OSA free of disease and 12 healthy control subjects. Plasma LOX-1 (pLOX-1) levels were measured using a commercially available enzyme-linked immunosorbent assay. Protein expression of LOX-1 was quantified by immunofluorescence in freshly harvested venous endothelial cells before and after 8 weeks of continuous positive airway pressure (CPAP) therapy. Circulating apoptotic endothelial cells (CD146(+), CD45(-), and CD31(1)) were assessed concomitantly by flow cytometry. RESULTS: pLOX-1 levels were higher in subjects with OSA than in control subjects (326.9 ± 267.1 pg/mL and 141.1 ± 138.6 g/mL, respectively; P = .004). Patients with OSA showed a threefold increase in baseline endothelial expression of LOX-1 relative to control subjects. CPAP therapy resulted in a significant decrease in endothelial LOX-1 expression only in CPAP-adherent patients. Circulating apoptotic endothelial cells correlated directly with baseline expression of LOX-1 (R(2) = 0.32, P = .01) after adjustment for age, BMI, and waist to hip ratio. CONCLUSIONS: Increased expression of LOX-1 in vivo is associated with endothelial apoptosis. Adherence to CPAP therapy may reverse these derangements.