Can Bariatric Surgery Cure Sleep Apnea?

The symptoms of obstructive sleep apnea, OSA, include sleepiness during the day (hypersomnia); snoring; episodes of choking, or breathing cessation, during sleep; awakening with a dry mouth or sore throat; and morning headaches. Sleep apnea is one of the risk factors for cardiovascular disease and also causes snoring.

The incidence of OSA has been shown to be almost 90% in severely obese patients. In fact, being overweight has been regarded as the most important cofactor contributing to the severity of OSA. For this reason, the treatment of OSA includes means to achieve substantial weight loss.

A logical question thus is: Can Bariatric Surgery cure Sleep Apnea?

In general, reliable and substantial weight loss, usually not achieved by dietary means, can be accomplished by bariatric surgery with accompanying major reductions in associated co-morbidities. Two operative approaches are commonly performed: vertical-banded gastroplasty (VBG) and Roux-en-Y gastric bypass. The loss of weight may be as much as 100 to 150 pounds within a year. The mechanism of this weight loss is twofold: decreased food intake, coupled with its malabsorption. This is because of the reduction in the size of the stomach as well as the rerouting of food to the small intestine which reduces the calories and nutrients absorbed by the body. In general, mean weight loss is greater after gastric bypass than after VBG.

Weight loss achieved by bariatric surgery has been reported to be associated with significant long-term improvements in obstructive respiratory events, oxygenation and resolution of daytime somnolence. Bariatric surgery may significantly reduce breathing interruptions during sleep, and reduce snoring. A possible mechanism for amelioration of symptoms is that weight loss is associated with a reduction in upper airway collapsibility and that resolution of sleep apnea depends on the absolute value to which the upper airway critical pressure falls.

The AASM recommends bariatric surgery as an optional treatment for severe obesity and sleep apnea. It is, however, mandatory that the surgical modalities be used only in association with a first-line treatment such as CPAP.

To clinically diagnose OSA and define its severity, though, sleep medicine doctors use the "apnea-hypoxia index" and those with mild OSA have 5-14 episodes of apnea-hypoxia an hour, while OSA is said to be severe if the number of apnea-hypoxic episodes per hour exceeds 30. There are no clear cut guidelines for determining which patients of OSA are ideal candidates for bariatric surgery.

Sleep apnea is one of the criteria used to support the 'medical necessity' of bariatric surgeries, even those with moderate obesity (BMI≥35) could be a candidate if their surgeon is convinced that they have a "serious obesity-related morbidity, such as obstructive sleep apnea." Therefore, if surgery is considered, the patient should be evaluated by a multidisciplinary team that incorporates medical, nutritional, and psychological care and proper counseling regarding its risk benefit ratio.

A systematic review and meta-analysis of a total of 22,094 patients revealed that obstructive sleep apnea was resolved in 85.7% of patients, and was partially resolved or improved in 83.6% of patients undergoing bariatric surgery.

No long-term outcome data exist to clearly demarcate how much of a reduction in the AHI or CPAP pressures is required to result in meaningful reductions in symptoms and co-morbidities related to OSA. As per researchers, a very small minority of patients actually experience resolution of obstructive events even after sustained weight loss and many continue to require CPAP therapy. In fact many patients reported no amelioration of symptoms like somnolence and snoring. It also has to be mentioned that in the long run, there are cases of recurrence of sleep apnea without concomitant weight increase.

Until the impact of surgical weight loss is better defined, patients should understand that they are likely to continue to require treatment for OSA. Patients and healthcare practitioners alike should recognize that reliance on bariatric surgery as a 'cure' for OSA may lead to an inappropriate cessation of CPAP therapy.

It is strongly recommended that CPAP be administered to these patients before surgery. Empiric CPAP at 10 cm H2O can be considered for those patients who cannot complete polysomnography, and the patient should continue to receive CPAP until broad weight reduction has been achieved. Especially during the immediate postoperative period, CPAP may be needed to protect the upper airway until sedative and muscle-relaxing drugs have been metabolized. The importance of a long term, meticulous follow up of these patients cannot be over emphasized.

It is essential to keep in mind that surgical weight loss alone cannot cure OSA, although it does tend to reduce the severity of disease and may lower CPAP pressures required to prevent apneic events.

Until randomized controlled trials prove its efficacy irrevocably, and more definitive guidelines for suitability of candidates are laid down, the use of bariatric surgery to cure sleep apnea remains largely empirical.


Copyright (c) 2009 Alma Orozco