"Off-pump bypass surgery has become a viable technique in the past five to six years because of new technology," says senior author Louis P. Perrault, M.D., Ph.D., a cardiovascular and thoracic surgeon at the Montreal Heart Institute (MHI) in Quebec. "However, until now, surgeons have been unable to identify in which patients the technique is most beneficial. This study provides striking evidence that patients over 80 are a subgroup who can benefit greatly from off-pump surgery."
During bypass surgery, surgeons make a detour around the blocked part of a coronary artery using a blood vessel from another part of the body. A key to success of the procedure has been the use of a cardiopulmonary bypass pump oxygenator – or heart–lung machine – that lets surgeons stop the heart during the operation but keep blood flowing to the rest of the body.
In off-pump bypass surgery, surgeons operate on a beating heart rather than shifting the heart's work to a mechanical pump.
Patients over age 80 are at high-risk for complications after bypass surgery. Some physicians have suggested the less invasive off-pump technique may be a better option for these patients. Researchers tested this theory by reviewing bypass surgery records. Between 1995–99, 125 patients over 80 had bypass surgery, 63 on-pump and 62 off-pump. The two groups were very closely matched in preoperative health characteristics, heart pumping strength, number of artery or vein grafts, and age and gender. The operative mortality – death occurring within 30 days of surgery – was 15.9 percent in the on-pump group and 4.8 percent in the off-pump group. Four postoperative strokes occurred in the on-pump group and none in the off-pump group. Another important difference was that the off-pump group needed fewer blood transfusions. A prospective randomized study is under way in their center to confirm these findings.
"Even though the design of this study isn't perfect," Perrault says, "the results are hard to ignore. If some centers are not believers in off-pump bypass surgery, these findings should encourage them to rethink their position in the over-80 group."
Co-authors are R.G. Demaria, M.D.; M. Carrier, M.D.; S. Fortier, M.D.; R. Martineau, M.D.; A. Fortier, M.Sc.; R. Cartier, M.D.; M. Pellerin, M.D.; Y. Hébert, M.D.; D. Bouchard, M.D.; and P. Pagé, M.D.
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