Coronary Artery Bypass: A Surgical Treatment for Coronary Artery Disease

Medically reviewed: 15, February 2024

Coronary Artery Bypass surgery: What is it?

Coronary artery disease is a prevalent and serious condition that arises from the narrowing or blockage of the arteries responsible for delivering blood to the heart. This occurs due to the accumulation of cholesterol and various other substances within these crucial passageways.

Consequently, individuals afflicted by this condition often experience discomfort in their chest, commonly referred to as angina, or may even suffer from a heart attack. The impact of coronary artery disease is not limited to a specific region, as it remains a significant contributor to both mortality and disability on a global scale, affecting a substantial number of adults solely within the United States.

Coronary artery bypass (CAB) is a surgical intervention designed to enhance blood circulation to the heart muscle by constructing alternative routes for blood to circumvent the constricted or obstructed coronary arteries. The primary goals of CAB are to alleviate angina symptoms, enhance overall cardiac performance, and decrease the likelihood of mortality resulting from coronary artery disease (CAD).

Undoubtedly, CAB stands as one of the prevailing and highly efficacious approaches to tackle CAD, as evidenced by the staggering number of over 200, 000 procedures carried out each year in the United States alone.

In this article, we will provide a comprehensive overview of CAB, including its indications, contraindications, types, techniques, outcomes, complications, and postoperative care. We will also discuss the current evidence and guidelines for CAB, as well as the future directions and challenges for CAB.

Indications and Contraindications for Coronary Artery Bypass

The indications and contraindications for CAB are based on the severity and extent of coronary artery disease, the symptoms and quality of life of the patient, the left ventricular function and anatomy of the heart, and the potential benefits and risks of CAB compared with other treatment options, such as medical therapy or percutaneous coronary intervention (PCI).

PCI is a minimally invasive procedure that uses a catheter to insert a balloon or a stent to widen the narrowed or blocked coronary artery.

The main indications for CAB are:

• Left main coronary artery disease.

It occurs when the main artery supplying blood to the left side of the heart is blocked, which can be very dangerous and potentially lead to sudden cardiac death or severe heart failure. In most cases, coronary artery bypass surgery is recommended for patients with this condition, unless they have a very low risk for surgery or a high risk for complications. This surgery aims to improve blood flow to the heart, reduce symptoms, and lower the risk of future heart problems.

• Single-vessel coronary artery disease.

This term refers to a blockage in only one coronary artery, while multivessel coronary artery disease involves blockages in two or more arteries. CAB surgery may be considered for patients with these conditions if they have persistent symptoms or a high risk for future cardiac events.

The main contraindications for CAB are:

• Blocked coronary arteries

Patients who do not have significant narrowing or blockage in their coronary arteries. It is a consequence for individuals who do not experience any symptoms or ischemia and do not have significant coronary artery disease do not necessitate the need for coronary artery bypass (CAB) surgery. Opting for CAB surgery in such cases would not yield any benefits and may even subject patients to unwarranted hazards.

• Diffuse coronary artery disease

On the other hand, individuals with diffuse or small-vessel coronary artery disease, where the arteries are very narrowed or even blocked or the arteries themselves are too small or twisted to be bypassed, also do not qualify for CAB. This is because performing CAB in such cases would not be technically feasible or effective and may actually cause more harm than good.

• Severe comorbidities or contraindications to surgery

which means that the patient has other serious medical conditions or factors that increase the risk of complications or death from CAB, or that prevent the patient from undergoing CAB. Examples of such conditions or factors include severe lung disease, liver disease, kidney disease, infection, bleeding disorder, or allergy to anesthesia. CAB is not indicated for patients who have severe comorbidities or contraindications to surgery, as it would be too risky or impossible to perform, and may outweigh the potential benefits.

Types and Techniques of Coronary Artery Bypass

There are different types and techniques of CAB, depending on the number and source of the grafts, the use of the cardiopulmonary bypass machine, and the state of the heart during the surgery. A graft is a blood vessel that is used to bypass a narrowed or completely blocked coronary artery.

The graft can be taken from the patient’s own body, such as the internal mammary artery, the radial artery, or the saphenous vein, or from a donor, such as a synthetic or biological graft. The cardiopulmonary bypass machine is a device that takes over the function of the heart and lungs during the surgery, by pumping and oxygenating the blood. The state of the heart during the surgery can be either arrested, which means that the heart is stopped and protected by a solution called cardioplegia, or beating, which means that the heart is still beating and perfused by the blood.

Conventional Coronary Artery Bypass

Conventional CAB, which is the most common and standard type of CAB, that involves the use of the cardiopulmonary bypass machine and the arrested heart. Such method typically uses two or more grafts, usually one or both internal mammary arteries and one or more saphenous veins, to bypass the diseased coronary arteries. It  has the advantage of providing a stable and bloodless surgical field, and allowing the use of multiple grafts and anastomoses, which are the connections between the grafts and the coronary arteries.

Speaking of disadvantages, conventional CAB has the disadvantage of requiring a longer and more complex surgery, and exposing the patient to the potential complications of the cardiopulmonary bypass machine, such as bleeding, inflammation, infection, stroke, or kidney injury.

Off-pump Coronary Artery Bypass

Off-pump CAB, which is a type of CAB that does not use the cardiopulmonary bypass machine and the arrested heart, but rather the beating heart. Off-pump CAB typically uses one or two grafts, usually one or both internal mammary arteries, to bypass the diseased coronary arteries. This type of surgery has the advantage of avoiding the complications of the cardiopulmonary bypass machine, and reducing the duration and invasiveness of the surgery. Disadvantage is – requiring a more skilled and experienced surgeon, and providing a less stable and more bloody surgical field, which may limit the number and quality of the grafts and anastomoses.

Minimally invasive Coronary Artery Bypass

Minimally invasive CAB, which is a type of CAB that uses smaller incisions and specialized instruments to perform the surgery, rather than the traditional sternotomy, which is the opening of the chest bone.

Surgery can be done either with or without the cardiopulmonary bypass machine and the arrested or beating heart, depending on the technique and the preference of the surgeon. Method typically uses one or two grafts, usually one or both internal mammary arteries, to bypass the diseased coronary arteries. It can reduce the trauma and pain of the surgery, and improve the cosmetic and functional outcomes. But you need to understand, that minimally invasive coronary artery bypass requires a more skilled and experienced professional, and being suitable only for selected patients with limited coronary artery disease.

Outcomes and Complications of Coronary Artery Bypass

The outcomes and complications of CAB depend on various factors, such as the type and technique of CAB, the characteristics and condition of the patient, the quality and patency of the grafts and anastomoses, and the postoperative care and follow-up. The outcomes and complications of CAB can be classified into short-term and long-term, depending on the time frame of their occurrence and impact.

The main short-term outcomes and complications of CAB are:

• Mortality, which is the death of the patient within 30 days of the surgery.

The mortality rate of CAB is about 1-3%, depending on the type and technique of CAB, and the risk factors of the patient. The most common causes of death after CAB are cardiac arrest, myocardial infarction, stroke, bleeding, infection, and organ failure.

• Morbidity

which is the occurrence of any adverse event or complication that affects the health or quality of life of the patient within 30 days of the surgery. The morbidity rate of CAB is about 10-20%, depending on the type and technique of CAB, and the risk factors of the patient.

The most common complications after CAB are arrhythmias, bleeding, infection, wound healing problems, stroke, kidney injury, and cognitive impairment.

Recovery after Coronary Artery Bypass surgery

Recovery, which is the process of healing and rehabilitation of the patient after the surgery. The recovery time of CAB varies depending on the type and technique of CAB, and the condition and compliance of the patient.

The main long-term outcomes and complications of CAB are:

Survival rate after coronary artery bypass

Survival, which is the length of time that the patient lives after the surgery. The survival rate of coronary artery bypass is about 85-90% at 10 years, and 60-70% at 20 years, depending on the type and technique of CAB, and the risk factors of the patient. The most common causes of death after CAB are cardiac causes, such as myocardial infarction, heart failure, or arrhythmias, or non-cardiac causes, such as cancer, stroke, or infection.

Graft failure

Graft patency, which is the openness and function of the grafts that are used to bypass the diseased coronary arteries. The graft patency rate of CAB is about 90-95% at 1 year, and 80-85% at 10 years, depending on the type and source of the grafts, and the condition of the patient. The most common causes of graft failure are graft occlusion, which is the blockage of the graft by atherosclerosis or thrombosis, or graft stenosis, which is the narrowing of the graft by intimal hyperplasia or kinking.

Graft failure can lead to recurrent angina, ischemia, or myocardial infarction.

Patient’s quality of life after coronary artery bypass

Quality of life, which is the physical, mental, and social well-being of the patient after the surgery. The quality of life of CAB is generally improved, as the patient experiences less angina, more exercise capacity, and better emotional and psychological status. However, some patients may experience residual or new symptoms, such as dyspnea, fatigue, depression, anxiety, or sexual dysfunction, which may affect their quality of life.

The quality of life of CAB is influenced by various factors, such as the type and technique of coronary artery bypass, the expectations and satisfaction of the patient, the support and coping of the patient and the family, and the adherence and compliance of the patient to the treatment and follow-up.

Postoperative Care and Follow-up of Coronary Artery Bypass

The average hospital stay after CAB is about 5-7 days, and the average return to normal activities is about 6 weeks. The recovery process of coronary artery bypass involves several aspects, such as wound care, pain management, medication, diet, exercise, and lifestyle modification.

The patient is advised to follow the instructions and recommendations of the surgeon and the health care team, and to report any signs or symptoms of complications or infection, such as fever, chest pain, shortness of breath, swelling, redness, or drainage from the incision site. Health workers also encourage the patient to participate in a cardiac rehabilitation program, which is a supervised and structured program that provides education, counseling, and exercise training to help the patient recover and prevent future cardiac events.

The postoperative care and follow-up of CAB are essential to ensure the safety and success of the surgery, and to optimize the long-term outcomes and quality of life of the patient. The postoperative care and follow-up of CAB involve several components, such as:

Medication after coronary artery bypass

The patient is prescribed and advised to take various medications after CAB, such as antiplatelets, statins, beta-blockers, angiotensin-converting enzyme inhibitors, and anticoagulants, to prevent graft failure, reduce the risk of recurrent cardiac events, and improve the function and structure of the heart. The patient is instructed to take the medications as prescribed, and to report any side effects or interactions to the health care provider.

Diet after coronary artery bypass

The patient is recommended to follow a healthy and balanced diet after CAB, such as the Mediterranean diet, the DASH diet, or the TLC diet, to lower the cholesterol and blood pressure levels, control the weight and blood sugar levels, and prevent the progression of atherosclerosis and CAD.

The patient is advised to limit the intake of saturated fat, trans fat, cholesterol, sodium, and added sugar, and to increase the intake of fruits, vegetables, whole grains, lean protein, and healthy fats, such as omega-3 fatty acids.

Exercises after coronary artery bypass

The patient is encouraged to engage in regular and moderate physical activity after coronary artery bypass, such as walking, cycling, swimming, or jogging, to improve the cardiovascular fitness, muscle strength, and endurance, and to reduce the stress and anxiety levels.

You must start slowly and gradually, and to follow the exercise prescription and guidance of the health care provider and the cardiac rehabilitation team. You can also be instructed to monitor the heart rate, blood pressure, and symptoms, and to avoid strenuous or vigorous exercise, especially in hot or cold weather, or at high altitude.

Lifestyle after coronary artery bypass

The patient is urged to adopt and maintain a healthy and positive lifestyle after CAB, such as quitting smoking, limiting alcohol consumption, managing stress, sleeping well, and adhering to the treatment and follow-up plan. The patient is also encouraged to seek and receive social and emotional support from the family, friends, and peers, and to participate in support groups, counseling, or therapy, if needed. There are courses and educations available for patients that empower them to recognize and cope with the potential challenges and difficulties that may arise after coronary artery bypass.

The postoperative care and follow-up of CAB require the active and collaborative involvement of the patient, the family, and the health care team, to achieve the best possible outcomes and quality of life. The postoperative care and follow-up of CAB are usually individualized and tailored to the specific needs and preferences of the patient, and may vary depending on the type and technique of coronary artery bypass, and the condition and progress of the patient. The postoperative care and follow-up of CAB are usually lifelong, as the patient needs to monitor and manage the health and function of the heart, and to prevent or treat any complications or comorbidities that may occur.

Evidence and Guidelines for Coronary Artery Bypass

The evidence and guidelines for CAB are based on the results and conclusions of various studies and trials that have compared and evaluated the efficacy and safety of CAB with other treatment options, such as medical therapy or PCI, for different types and subsets of patients with coronary artery bypass. The evidence and guidelines for CAB are constantly updated and revised, as new and emerging data and information become available and relevant, can be influenced by various factors, such as the availability and accessibility of the resources and technologies, the expertise and experience of the health care providers, and the values and preferences of the patients.

The main sources and references of the evidence and guidelines for CAB are:

• American College of Cardiology (ACC) and the American Heart Association (AHA) Guidelines for the Management of Patients with Coronary Artery Disease, which provide the recommendations and classifications for the diagnosis and treatment of CAD, including CAB, based on the level of evidence and the strength of recommendation.
• European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS) Guidelines on Myocardial Revascularization, which provide the recommendations and indications for the revascularization of CAD, including CAB, based on the level of evidence and the class of recommendation.
• Society of Thoracic Surgeons (STS) and the Society of Cardiovascular Anesthesiologists (SCA) Clinical Practice Guidelines for CAB, which provide the recommendations and standards for the perioperative management and care of CAB, based on the level of evidence and the grade of recommendation.

The guidelines are intended to assist and guide the health care providers and the patients in making informed and shared decisions about the best treatment option for each individual case of coronary artery bypass.

They are not meant to replace or override the clinical judgment and expertise of the health care providers, or the values and preferences of the patients, but subject to change and modification, as new and emerging evidence and information become available and relevant.

Future Directions and Challenges for Coronary Artery Bypass

CAB is a well-established and effective treatment for CAD, that has improved the survival and quality of life of millions of patients worldwide. However, CAB is also a complex and invasive surgery, that involves various risks and complications, and requires lifelong care and follow-up. Coronary artery bypass is also facing various challenges and limitations, such as the increasing prevalence and complexity of CAD, the rising costs and demands of health care, the variability and disparity of the quality and outcomes of CAB, and the rapid development and innovation of the alternative and competing treatment options, such as medical therapy or PCI.

Therefore, CAB needs to evolve and adapt to the changing and challenging environment and circumstances, and to address the unmet and emerging needs and expectations of the patients and the health care system. Some of the possible future directions and challenges for CAB are:

Improving the patient selection and stratification for coronary artery bypass, by using more accurate and reliable risk scores, biomarkers, imaging modalities, and decision aids, to identify and select the most appropriate and optimal candidates for CAB, and to avoid unnecessary or inappropriate CAB.

Making better the graft selection and optimization for coronary artery bypass, by using more durable and compatible grafts, such as arterial grafts, hybrid grafts, or bioengineered grafts, to improve the patency and function of the grafts, and to reduce the failure and complications of the grafts.

Working on surgical technique and technology for coronary artery bypass, by using more advanced and sophisticated instruments, devices, and systems, such as robotic surgery, endoscopic surgery, or 3D printing, to improve the precision and efficiency of the surgery, and to reduce the trauma and invasiveness of the surgery.

Fixing issues with the perioperative management and care for coronary artery bypass, by using more effective and safe medications, protocols, and strategies, such as enhanced recovery after surgery, fast-track surgery, or blood conservation, to improve the outcomes and quality of care, and to reduce the morbidity and mortality of CAB.

Postoperative follow-up and rehabilitation for coronary artery bypass – making it better by using more comprehensive and personalized programs and services, such as telemedicine, home-based care, or mobile health, to improve the access and adherence of the patient, and to monitor and manage the health and function of the heart, and to prevent or treat any complications or comorbidities that may occur.

Conducting more rigorous and relevant studies and trials, such as randomized controlled trials, comparative effectiveness research, or cost-effectiveness analysis, to compare and evaluate the efficacy and safety of coronary artery bypass with other treatment options, for different types and subsets of patients with CAD, and to update and revise the recommendations and indications for CAB, based on the best available evidence and information.

Better quality and outcomes of coronary artery bypass, by implementing more standardized and quality measures and indicators, such as process, structure, and outcome measures, to assess and monitor the performance and quality of CAB, and to identify and address the gaps and challenges in coronary artery bypass, and to improve the consistency and accountability of CAB.

Education and training: developing and providing more advanced and innovative curricula and programs, such as simulation, virtual reality, or artificial intelligence, to enhance the skills and competencies of the health care providers, and to foster a culture of learning and improvement for CAB.

Improving the patient-centeredness and shared decision-making for CAB, by involving and engaging the patient and the family in the diagnosis and treatment of CAD, and by providing more accurate and reliable information and tools, such as risk calculators, decision aids, or patient-reported outcomes, to help the patient and the health care provider to make informed and shared decisions about the best treatment option for each individual case of CAD.