For > 20 years, being overweight has been regarded as the most important cofactor contributing to the severity of obstructive sleep apnea (OSA). (1) For this reason, the treatment of OSA includes means to achieve substantial weight loss. In this issue of CHEST (see page 618), Busetto et al introduce intragastric balloons into the field of bariatric surgery for OSA.
Weight loss associated with almost complete resolution of sleep apnea was observed by Schwartz et al (2) in patients with OSA in whom the upper airway critical pressure fell below < 4 cm [H.sub.2]O. They concluded that weight loss was 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. Unfortunately, only a few patients with sleep-related breathing disorders succeed in maintaining their dietary-achieved weight reduction. Guilleminault (3) reports that only 3% of patients with OSA who had a significant improvement in their sleep apnea symptoms as a result of dietary weight loss maintained their weight after 5 years; many patients, in fact, regained their weight and even exceeded their baseline weights.
In a series (4) of 216 overweight patients with OSA, resolution of OSA by means of dietary weight loss alone was successful in 11.1% of patients (n = 24). Patients were reexamined after an average of 94.3 [+ or -] 27.4 months in this study; while 13 patients had maintained their weight, 11 had regained lost weight. Furthermore, 6 of the 13 patients (46%) who had maintained their weight had clinical OSA redevelop (apnea-hypopnea index [AHI], 40.5 [+ or -] 24.1). However, 9 of 11 patients (82%) who had regained lost weight manifested OSA. Thus, after 3 years, only 3% of patients showed long-term relief of OSA.
Much more promising 5-year results were reported by Guilleminault (3) in morbidly obese women who had undergone gastric surgery. Prior to 1999, the performance of bariatric surgery was largely done using an open technique. The number of procedures done in the United States was relatively stable, with between 10,000 and 15,000 per year. The numbers increased to 75,000 in 2002. Much of the increase in the number of procedures performed reflects the sudden explosion during this time of the use of a laparoscopic approach for the performance of bariatric surgery. (5) Two operative approaches are commonly performed: vertical-banded gastroplasty (VBG) and Roux-en-Y gastric bypass. (6,7) By limiting the storage capacity of the stomach to 30 to 50 [micro]L and reducing the pouch-emptying rate by creating a 10-mm in diameter anastomotic GI stoma, these two gastric-restrictive surgeries significantly reduce the total volume and rate at which food can be consumed. The gastric bypass further limits caloric intake by inducing a dumping syndrome whenever sugar is consumed. (8) In general, mean weight loss is greater after gastric bypass than after VBG.
In general, reliable and substantial weight loss can be accomplished by gastric bypass surgery with accompanying major reductions in associated comorbidities. (9) The currently still-limited polysomnographic data on the effect of gastric surgery for OSA are listed in Table 1. In addition to the data presented in Table 1, we found a case report of successful normalization of severe OSA and morbid obesity after vertical silastic ring gastroplasty. (15) Three months after surgery, the patient stopped nasal continuous positive airway pressure (CPAP) ventilation during his 2-week holiday without reoccurrence of daytime fatigue.
It has to be mentioned, however, that in the long run there are cases of recurrence of sleep apnea without concomitant weight increase, as described in 14 cases 7.5 years after successful weight reduction surgery. (16) Nevertheless, weight loss after bariatric surgery seems to remain much more stable than after dietary weight reduction.
The incidence of OSA has been shown to be almost 90% in severely obese patients. (17) Therefore, it is strongly recommend to administer CPAP to these patients before surgery. Empiric CPAP at 10 cm [H.sub.2]O can be considered for those patients who cannot complete polysomnography. 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. (18)
As mentioned, many surgeons now perform these procedures using a laparoscopic approach, thus minimizing hospital stay and time of recovery. Complications after bariatric surgery can be classified into intraoperative, perioperative, and late complications. As intraoperative complications, iatrogenic splenectomics are reported after open gastric bypass operations. Podnos and colleagues (19) analyzed the complications after 3,464 gastric bypass operations, published in 17 articles, for morbid obesity. Within the perioperative period, the following incidences of complications in open gastric bypass vs laparoscopic gastric bypass were calculated: anastomotic leaks (1.7% vs 2.1%, p = 0.31), bowel obstruction (not reported vs 1.7%), GI tract hemorrhage (0.6% vs 1.9%, p = 0.008), pulmonary embolus (0.8% vs 0.4%, p = 0.09), wound infection (6.6% vs 3.0%, p < 0.001), pneumonia (0.3% vs 0.1%, p = 0.24), and death (0.9% vs 0.2%, p = 0.001). As late complications, bowel obstruction (2.1% vs 3.2%, p = 0.02), incisional hernia (8.6% vs 0.5%, p <0.001), and stomal stenosis (0.7% vs 4.7%, p < 0.001) were identified. In other words, endoscopic procedures reduce the risk of morbidity (especially hernias and wound infections) and mortality as compared to the open approach. Nevertheless, severe complications still occur. A detailed report on potential complications of surgery for obesity is given by Byrne. (20) If surgery is considered, the patient should be evaluated by a multidisciplinary team that incorporates medical, nutritional, and psychological care. (21) Some preoperative factors predicting complicated postoperative management after endosopic Roux-en-Y gastric bypass operations have been identified: body mass index (BMI) > 50 kg/[m.sup.2], FE[V.sub.1] < 80%, previous abdominal surgeries, and abnormal ECG. (22)
Busetto and colleagues present very beneficial results after the use of intragastric balloons with regard to the severity of OSA. Intragastric balloons can be regarded as standard procedure for weight reduction; for the first time, their effects on the severity of OSA are described. As compared to endoscopic bariatric surgery, intragastric balloons seem to cause fewer deaths and complications (not one significant complication in the series of Busetto et al), and to show comparable efficacy. Based on these facts, Busetto and colleagues add important new knowledge about modern sleep medicine, although its study design (case series) does not allow a high grade of recommendation according to evidence-based medicine to date.
Thomas Verse, MD
Dr. Verse is Assistant Professor and Provisional Head of the Department of Otolaryngology, Head and Neck Surgery of the University of Saarland, Homburg, Germany.
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).
Correspondence to: Thomas Verse, MD, Department of Otolaryngology, Head and Neck Surgery, University of Saarland, Kirrberger Strasse, D-66421 Homburg, Germany; e-mail: firstname.lastname@example.org
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