Q: Is it true that there is a surgical procedure to lower cholesterol?
A: A surgical procedure, partial ileal bypass, does reduce cholesterol, and has been used on a small number of people with an elevated cholesterol for more than 25 years.
In this operation the continuity of the final part of the small intestine (ileum) is interrupted by cutting it and attaching it to the large intestine (colon). As a result, intestinal contents bypass the last third of the ileum, the site of most of the absorption of cholesterol and bile acids. Thus, the operation leads to a reduction in serum cholesterol levels.
What is new is a report in an early October issue of the New England Journal of Medicine comparing the outcomes of a control group of 417 patients and a surgically treated group of 421 patients over an average of almost 10 years.
The bypass patients had, on average, a 23 percent lower cholesterol level and a 35 percent lower incidence of fatal and non-fatal heart attacks compared with the control group, and these differences were statistically valid. The surgically treated group also needed far few coronary bypass operations and angioplasties.
X-ray examinations of the coronary arteries further showed that the ileal bypass patients had a slower progression of the atherosclerotic narrowings in their coronaries. The importance of this study rests mainly with the further evidence it provides for the benefits of lowering cholesterol levels since diet and drugs are more commonly used in that effort.
Diarrhea, kidney stones and gallstones are the most common complications of ileal bypass. These side effects led to operations to reverse the bypass procedure in about 6 percent of the patients.
The ileal bypass operation still has only a limited place in the treatment of people with a high blood cholesterol, especially now that safe new drugs are even more effective than bypass in lowering cholesterol levels. The bypass procedure may be worth considering in individuals who fail to respond or are unable to tolerate the side effects of medications.
Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine and associate dean for academic affairs at the school.