Updated March 26, 2015.
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.
In recent years, surgery for obesity (bariatric surgery) is being used more commonly as a method to achieve weight loss. Weight loss surgery reduces the effective size of the stomach, usually either by gastric banding (placing an adjustable band around the stomach) or by gastric bypass (surgically isolating a large portion of the stomach), and thus greatly limits the volume of food that can be ingested at any one time.
Either type of bariatric surgery can produce significant weight loss. However, this surgery carries significant risk, so it is usually reserved for individuals who are so obese (that is, whose body mass index, BMI, is 40 or higher) that the obesity itself produces significant risk. You can read more about bariatric surgery at About.com's Weight Loss site.
Because obesity is a significant risk factor for cardiovascular disease, it has generally been assumed that bariatric surgery would reduce cardiac risk. However, solid evidence has been lacking that weight loss surgery actually accomplishes this risk reduction.
To examine this question, investigators from the Mayo Clinic recently conducted a retrospective study of patients who have had bariatric surgery for extreme obesity. First, they conducted a thorough review of all reported medical studies on bariatric surgery, and found that patients who had this surgery had significant reductions in cardiac risk factors including weight, blood sugar, cholesterol and blood pressure.
They then computed Framingham risk scores for obese patients who had bariatric surgery, and compared them to obese patients (control patients) who did not have the surgery. They found that obese patients who had weight loss surgery had a significant improvement in predicted cardiovascular risk compared to patients not having surgery. The estimated 10-year reduction in cardiovascular events (such as heart attack and stroke) among the surgery patients was between 20% and 80%. (You can compute your own 10-year Framingham risk score here.)
This study does not prove that weight loss surgery reduces cardiovascular events. Only a large, randomized clinical trial looking at actual long-term clinical outcomes could do that. However, it does provide strong suggestive evidence that, in extremely obese individuals, bariatric surgery can significantly reduce long-term cardiovascular risk.
Recommended reading:
Weight Loss Surgery from About.com's Surgery Site
About.com's Weight Loss Site
Sources:
Batsis JA, Sarr MG, Collazo-Clavell ML, et al. Cardiovascular risk after bariatric surgery for obesity. Am J Cardiol 2008; DOI:10.1016/j.amjcard.2008.05.040.
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