Improving outcomes for coronary artery bypass surgery
If you have coronary artery disease (CAD), in which one or more of the main blood vessels feeding your heart is blocked, you may be facing coronary artery bypass surgery. A desire to improve outcomes after surgery and advances in technology have led surgeons to perform coronary artery bypass surgery without cardiopulmonary bypass, called off-pump bypass (also called "beating heart") surgery.
Traditionally, coronary artery bypass surgery is performed with the assistance of cardiopulmonary bypass. The heart-lung machine allows the heart’s beating to be stopped, so that the surgeon can operate on a surface which is blood-free and still. The heart-lung machine maintains life despite the lack of a heartbeat, removing carbon dioxide from the blood and replacing it with oxygen before pumping it around the body. The heart-lung machine has saved countless lives.
Off-pump coronary artery bypass surgery differs from traditional coronary artery bypass surgery, because the heart-lung machine is not used. Rather than stopping the heart, technological advances and new kinds of operating equipment now allow the surgeon to hold stabilize portions of the heart during surgery. With a particular area of the heart stabilized, the surgeon can go ahead and bypass the blocked artery in a highly controlled operative environment. Meanwhile, the rest of the heart keeps pumping and circulating blood to the body.
Off-pump coronary artery bypass surgery may be performed in certain patients with coronary artery disease. With present technology, all arteries on the heart can be bypassed off-pump. It may be ideal for certain patients who are at increased risk for complications from cardiopulmonary bypass, such as those who have heavy aortic calcification, liver cirrhosis, or compromised pulmonary or renal function. Not all patients are a candidate. The selection of patients who undergo off-pump surgery is made at the time of surgery when the patient's heart and arteries are evaluated more closely.
Off-pump coronary artery bypass surgery is now possible, but is it better?
The aims of off-pump bypass surgery is to decrease the morbidity of coronary artery bypass surgery, such as stroke, renal failure and need for blood transfusion. Also of great interest is the possibility that the off-pump approach may lessen the risk of what are called cognitive changes that have been seen in many patients who underwent CABG with cardiopulmonary bypass.
Surgeons at The Cleveland Clinic completed a study comparing the results of on- and off-pump coronary artery bypass surgery. The researchers matched 406 off -pump and 406 on-pump patients for comparison.
They found that the results of both on- and off-pump surgeries were excellent. The risk of stroke, heart attack during surgery, and death were similar and low in patients undergoing both on- and off-pump CABG. One concern that emerged from recent multi-center studies is that off-pump patients had more incomplete revascularization, meaning that less patients had blood flow fully restored than on-pump patients. In fact, a review of the national trends in bypass surgery demonstrated that fewer surgeons are now performing off-pump CABG. However, note that surgeons should be able to completely revascularize almost all patients.
Theresults of both on- and off-pump coronary bypass operations are excellent. Both have a very low risk of death, stroke, and myocardial infarction (heart attack). The advantage of off-pump surgery is that we can significantly reduce the morbidity of coronary artery bypass in appropriately selected patients. We tailor the operation to the patient’s specific needs and circumstances. The end result equals better outcomes for patients.
Are there patients who might benefit from off-pump surgery?
Patients at high risk for complications from cardiopulmonary bypass, such as people with vascular (blood-vessel) disease, previous strokes or liver disease may benefit from off-pump revascularization.
Surgeons are continually looking at ways to improve the outcomes in both kinds of surgery. For example, in on-pump surgery, improvements are being made to the heart-lung machine, and a filtration device that can capture tiny emboli before they do any damage has been designed and is being tested. In off-pump surgery, different ways of stabilizing small portions of the heart are being researched.