Evolution and Predictive Factors of Improvement of Obstructive Sleep Apnea in an Obese Population After Bariatric Surgery.

STUDY OBJECTIVES: Our objectives were to determine in an obese population (body mass index > 35 kg/m²) the number of patients, after gastric bypass (GBP), who no longer met French Ministry of Health criteria for utilizing positive airway pressure (PAP), and the predictive factors of obstructive sleep apnea (OSA) improvement. METHODS: Between June 2012 and August 2014 we diagnosed OSA in 129 incident patients requiring PAP therapy before GBP. A postoperative sleep recording was undertaken for 44 of these patients after a weight loss of at least 10%. RESULTS: Most of the patients showed severe OSA with a mean [standard deviation] apnea-hypopnea index (AHI) of 52.8 [23.8] events/h. The body mass index was 46.1 [5.1] kg/m². All the patients were treated via PAP and most of them via auto-titrating PAP with a range of 4-16 cmH2O. Following the GBP, in 31 patients (70.5%) OSA was improved, allowing PAP to be stopped (AHI < 15 events/h). The Epworth Sleepiness Scale score, the modified Medical Research Council dyspnea scale, the loudness of snoring, and sleep structure were improved. AHI was decreased by a mean of 40.9 [22.4] events/h (P < .001). In a multivariate logistic regression model, age (P = .018) and sleep oxygen desaturation index (P = .049) appeared to predict improvement of OSA. CONCLUSIONS: After GBP, 70.5% of the patients no longer met French Ministry of Health criteria for utilizing PAP, allowing discontinuation of this treatment. At diagnosis, a younger age and a less severe sleep oxygen desaturation were predictive factors of this improvement.

Prognostic value of exercise pulmonary haemodynamics in pulmonary arterial hypertension.

The aim of the study was to investigate the prognostic value of right heart catheterisation variables measured during exercise. 55 incident patients with idiopathic, familial or anorexigen-associated pulmonary arterial hypertension (PAH) underwent right heart catheterisation at rest and during exercise and 6-min walk testing before PAH treatment initiation. Patients were treated according to recommendations within the next 2 weeks. Right heart catheterisation was repeated 3-5 months into the PAH treatment in 20 patients. Exercise cardiac index decreased gradually as New York Heart Association (NYHA) functional class increased whereas cardiac index at rest was not significantly different across NYHA groups. Baseline 6-min walk distance correlated significantly with exercise and change in cardiac index from rest to exercise (r=0.414 and r=0.481, respectively; p<0.01). Change in 6-min walk distance from baseline to 3-5 months under PAH treatment was highly correlated with change in exercise cardiac index (r=0.746, p<0.001). The most significant baseline covariates associated with survival were change in systolic pulmonary artery pressure from rest to exercise and exercise cardiac index (hazard ratio 0.56 (95% CI 0.37-0.86) and 0.14 (95% CI 0.05-0.43), respectively). Change in pulmonary haemodynamics during exercise is an important tool for assessing disease severity and may help devise optimal treat-to-target strategies.