Effects of continuous positive airway pressure treatment on coronary vasoreactivity measured by (82)Rb cardiac PET/CT in obstructive sleep apnea patients.

PURPOSE: Obstructive sleep apnea syndrome (OSA) increases the risk of cardiovascular disease. We aimed at evaluating the effect of continuous positive airway pressure (CPAP) treatment on coronary endothelium-dependent vasoreactivity in OSA patients by quantifying myocardial blood flow (MBF) response to cold pressure testing (CPT). METHODS: In the morning after polysomnography (PSG), all participants underwent a dynamic (82)Rb cardiac positron emitting tomography/computed tomography (PET/CT) scan at rest, during CPT and adenosine stress. PSG and PET/CT were repeated at least 6 weeks after initiating CPAP treatment. OSA patients were compared to controls and according to response to CPAP. Patients' characteristics and PSG parameters were used to determine predictors of CPT-MBF. RESULTS: Thirty-two untreated OSA patients (age 58201;±201;13 years, 27 men) and 9 controls (age 62201;±201;5 years, 4 men) were enrolled. At baseline, compared to controls (apnea-hypopnea index (AHI)201;=201;5.3201;±201;2.6/h), untreated OSA patients (AHI201;=201;48.6201;±201;19.7/h) tend to have a lower CPT-MBF (1.1201;±201;0.2 mL/min/g vs. 1.3201;±201;0.4 mL/min/g, p201;=201;0.09). After initiating CPAP, CPT-MBF was not different between well-treated patients (AHI <10/h) and controls (1.3201;±201;0.3 mL/min/g vs. 1.3201;±201;0.4 mL/min/g, p201;=201;0.83), but it was lower for insufficiently treated patients (AHI ≥10/h) (0.9201;±201;0.2 mL/min/g vs. 1.3201;±201;0.4 mL/min/g, p201;=201;0.0045). CPT-MBF was also higher in well-treated than in insufficiently treated patients (1.3201;±201;0.3 mL/min/g vs. 0.9201;±201;0.2 mL/min/g, p201;=201;0.001). Mean nocturnal oxygen saturation (β201;=201;-0.55, p201;=201;0.02) and BMI (β201;=201;-0.58, p201;=201;0.02) were independent predictors of CPT-MBF in OSA patients. CONCLUSIONS: Coronary endothelial vasoreactivity is impaired in insufficiently treated OSA patients compared to well-treated patients and controls, confirming the need for CPAP optimization.