Nov. 23, 2024
Mayo Clinic cardiovascular surgeons perform low-risk coronary artery bypass grafting (CABG) while providing durable outcomes for coronary artery disease. The surgery can reduce a patient's chest pain, difficulty breathing and risk of heart disease-related death. Here, John M. Stulak, M.D., a cardiovascular surgeon at Mayo Clinic in Rochester, Minnesota, answers questions about CABG options that can offer patients a longer and better quality of life.
Why is coronary artery bypass grafting (CABG) important to the field and to patients?
Heart disease remains the leading cause of death in both men and women, with coronary artery disease and heart attack topping those causes. Patients may need CABG if they have blockages in the coronary arteries due to coronary artery disease. The blockages obstruct blood flow to the heart muscle. If stenting is not an option, CABG is the preferred approach to address the disease completely and create a new path for blood to flow around a blocked or partially blocked artery in the heart. The surgery involves taking a healthy blood vessel from the chest or leg area. The vessel is connected below the blocked heart artery.
Advances in medications have helped improve the longevity of CABG. Surgeons perform CABG either using the heart-lung bypass machine or without it. Improvements in perioperative care, operative technique and postoperative management have resulted in a low risk for CABG while providing a durable and long-lasting option for the patient.
How do you choose conduits, and which vessels are associated with longevity?
We consider the risks, benefits and expected longevity of the patient when we evaluate for graft use. We look at patient-related factors, including diabetes, chronic lung disease, obesity and bone quality, that could affect wound healing.
Possible CABG vessel choices:
- Left internal mammary artery from under the left chest wall to revascularize the left anterior descending coronary artery provide a significantly longer survival compared with when it's not used in bypass surgery.
For blocked coronary arteries in the right coronary artery and left circumflex coronary artery territories:
- Saphenous vein from the legs has been the most used vessel historically for the other coronary territories. The saphenous vein is predictable and easy to work with. However, veins were not created to withstand the higher pressure of the arterial side of the circulation for long periods of time. They don't last indefinitely. They can dilate over time, resulting in clogging. For older patients who are not expected to live more than 15 years, this is the standard choice.
- Radial artery in the forearm is a thicker vessel and designed to handle the arterial pressure. The conduit lasts longer than saphenous veins and is considered in younger patients who have a longer time to live.
- Right internal mammary artery is an excellent choice for young patients since the internal mammary arteries secrete their own dilating substance called nitric oxide, which keeps the vessels patent and resists further coronary artery disease. This vessel is thought to last as long as the left internal mammary artery. For young patients, this also is considered part of a multiple arterial grafting approach.
Are there special patient populations that benefit most from CABG, and for which patients would CABG be cautioned?
Patients with multiple coronary artery vessels affected by disease and concomitant comorbidities such as diabetes, either in isolation or together, are better served with CABG than stenting or medical therapy. Multiple arterial grafting often confers far longer duration of revascularization for the younger patient compared with stenting. The patient's entire health status is considered when deciding if surgery is more advisable. Significantly older patients and those with a high burden of additional disease may not represent safe surgical candidates. This is a discussion between the surgeon, cardiologist and patient.
What is the long-term maintenance for patients following CABG?
Coronary artery bypass grafting is not a cure. It is simply the resetting of a clock. That clock represents the progressive nature of coronary artery disease.
Saphenous vein grafts and radial artery grafts are at risk of the same impact of coronary artery disease as native coronary arteries are. That is also why these grafts do not last indefinitely. Because of this, maintenance therapy with medications as well as optimizing patients' behaviors are critical. Patients are encouraged to regularly meet with their primary care physician or cardiologist for ongoing medical maintenance and prevention.
What will physicians need to focus on moving forward with CABG advancements and innovation?
The increasing use of arterial grafts for bypass selection is crucial. Yet, a minority of patients who are candidates for multiple arterial grafting receive these conduits. That's likely due to challenges of multiple arterial grafting being a newer or unconventional approach. The surgery takes longer due to the time needed to harvest bilateral internal mammary conduits and because mammary arteries are more technically challenging to work with. More stress should be put on the long-term aspects of coronary artery bypass grafting.
There are numerous innovations that are ongoing in the field of coronary artery bypass grafting. Minimally invasive options for left internal mammary artery (LIMA) to left anterior descending (LAD) coronary artery bypass may usher in an era of hybrid revascularization. The patient will have the long-term survival benefit of the LIMA to LAD graft in a minimally invasive fashion and then stenting to the other vessels to minimize the invasiveness and recovery from surgery. This would open the doors to many patients who ordinarily are undergoing stenting to the LAD now, especially patients with diabetes who receive an enhanced survival advantage from the LIMA to the LAD.
For more information
Refer a patient to Mayo Clinic.