Effect of bariatric surgery on obstructive sleep apnea and hypopnea syndrome, electrocardiogram, and pulmonary arterial pressure

Background: We evaluated the impact of surgically-induced weight loss on Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS), electrocardiographic changes, pulmonary arterial pressure and daytime sleepiness in morbidly obese patients. Methods: 16 women and 13 men (n = 29) underwent bariatric surgery in a 3-year period. The following tests were performed before and 1 year after surgery; nocturnal polysomnography, daytime Multiple Sleep Latency Test (MSLT), and echocardiogram. Results: Mean age was 37.9 +/- 11 years (range 20-56). Preoperative body mass index was 56.5 +/- 12.3 kg/m(2) and it was 39.2 +/- 8.5 kg/m(2) at 13.7 +/- 6.6 months follow-up. Performed surgical procedures included: vertical banded gastroplasty in 6, Roux-en-Y gastric bypass in 12, and Distal Roux-en-Y gastric bypass in 11. Weight loss induced by surgery eliminated OSAHS in 46% of obese patients with an important improvement in oxygen saturation. Neck, thorax, waist and hip circumferences decreased significantly after surgical intervention but only neck circumference correlated significantly with the apnea/hypopnea index (Spearman rho = 0.63, P < 0.0001). Electrocardiographic abnormalities were present in 9 patients (31%) before surgery (sinus arrhythmia, ventricular arrhythmias, and sinus arrest). The number of electrocardiographic abnormalities decreased after surgery but new abnormalities appeared in some patients. Systolic pulmonary arterial pressure significantly decreased in the group of patients in whom OSAHS disappeared after surgery. Daytime sleepiness persisted after surgery in most patients. Conclusion: Bariatric surgery effectively reduces respiratory disturbances during sleep and improves pulmonary hypertension. Electrocardiographic abnormalities change after surgery. Daytime sleepiness appeared not to be related to respiratory disturbances during sleep.