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Weight loss prior to gastric bypass surgery improves outcomes in very obese patients, data indicate

Thursday, October 16 2008 | Comments

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What's This? By Courtneay Parsons

In very obese patients scheduled to undergo gastric bypass surgery, preoperative weight loss with a very-low-calorie diet (VLCD) may improve postoperative outcomes, according to findings from a prospective study.

Dr. George Eid, section chief of surgery at the Veterans Affairs Pittsburgh Healthcare System, noted that morbidity and mortality after gastric bypass surgery are elevated in patients with certain risk factors, which include male sex, a body mass index (BMI) >50 kg/m2, older age, and lower socioeconomic status. In addition, he added, a BMI >50 kg/m2 can pose technical challenges for a bariatric surgeon due to factors such as excess visceral fat, an enlarged liver, and a thick abdominal wall.

As a result, Dr. Eid and colleagues evaluated the effects of a high-protein, liquid VLCD (approximately 800 calories/day) on preoperative body weight, obesity-related comorbidities, and computed tomography (CT) measurements of liver size and visceral and subcutaneous adipose tissue volumes. The research group also explored the relationship between changes in these parameters and postoperative outcomes.

The study included consecutive patients with a BMI >50 kg/m2 (n=30; 27 men; mean age, 53 yrs) who underwent Roux-en-Y gastric bypass surgery using the University of Pittsburgh technique. Prior to surgery, patients received the VLCD for an average of 9 weeks (range, 4-13 wks).

Subjects had >=3 comorbidities, including sleep apnea, poorly controlled diabetes or hypertension, congestive heart failure, degenerative joint disease with limited mobility, and chronic obstructive pulmonary disease. For individuals with a BMI between 50 and 55 kg/m2, the weight loss target was 10% of their total body weight; among those with a BMI >60 kg/m2, the target was a BMI <55 kg/m2.

From baseline to the end of treatment with the VLCD, 62.5% of patients showed improvement or resolution of diabetes, 40% showed improvements in blood pressure, and 57% showed improved mobility.

Total body weight declined a median of 12% with the VLCD, BMI declined from 56 kg/m2 to 49 kg/m2, liver volume declined 20%, and visceral fat declined 8%. Excluding 3 patients whose CT scans recorded a potentially erroneous increase in visceral fat, the remaining patients demonstrated a decline of as much as 20%.

In terms of postoperative outcomes, there were no mortalities and there were 2 postoperative complications, including 1 patient with tachycardia (suggesting possible pulmonary embolism) and 1 patient with minor bleeding.

Thus, the rates of mortality and morbidity were 0% and 6.7%, respectively. These estimates, Dr Eid noted, compare favorably with data from a high-risk subset of VA patients included in a previous trial; in that group, mortality rates were as high as 2.3% and morbidity rates were as high as 29%. (Part of: General Surgery 1 Paper Session GS58.)

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