Introduction

Coronary Artery Bypass Grafting (CABG) is a surgical procedure designed to restore blood flow to the heart muscle by bypassing blocked or narrowed coronary arteries. The primary goal is to alleviate the symptoms of coronary artery disease to improve the patient's quality of life and prevent further complications such as heart attacks.

CABG is a crucial surgical procedure designed to address the impact of coronary artery disease (CAD) on the heart. Cardiovascular disease is the leading cause of death worldwide, accounting for 31% of all registered deaths, and is expected to continue in this position until 2030. Whereas CAD is the leading cardiovascular cause of death in developed countries.¹ CABG is, currently, the most commonly performed cardiac surgery procedure worldwide with a history that can be traced back more than 100 years.² 

Anatomy of the coronary arteries

To comprehend the significance of CABG, it's essential to understand the intricate network of blood vessels that supply the heart – the coronary arteries. These arteries are vital in delivering oxygen and nutrients to the heart muscle. The coronary arteries can become narrowed over time, leading to a decrease in the heart's blood supply. 

When these arteries become narrowed or blocked due to the buildup of plaque, it results in coronary artery disease. This process is known as atherosclerosis. 

A decrease in blood supply to the heart can lead to chest pain (angina), shortness of breath, and, in severe cases, heart attacks. Some cases of angina may require a CABG to improve the blood supply to the heart. Despite the introduction of other treatment methods, CABG remains the “gold standard” treatment for multivessel coronary artery disease, particularly for three-vessel or left main coronary artery disease.² Another risk associated with coronary artery disease is the possibility of rupture in the plaques creating a blood clot that can block the artery.

Indications for CABG

• Left main coronary artery block
• Three-vessel coronary artery block of greater than 70% 
• When angioplasty or stenting is not feasible

Procedure of CABG

CABG is defined as open-heart surgery in which a section of a blood vessel is grafted from the aorta to the coronary artery to bypass the blocked section of the coronary artery and improve the blood supply to the heart.⁴ The CABG procedure involves creating alternative pathways for blood to reach the heart muscle. This is achieved by using grafts, typically harvested from other blood vessels in the body, to bypass the blocked or narrowed segments of the coronary arteries.

Multiple vessels may be used to re-establish cardiac revascularization. The saphenous vein in the leg is the most commonly used vessel in patients undergoing CABG. Other vessel options that have been used in CABG include the radial artery, internal mammary artery, gastroepiploic artery, and inferior epigastric arteries.^4,5 The severity of CAD and the amount of narrowing of the coronary arteries will determine how many grafts are required. 

Before undergoing CABG, patients undergo a thorough evaluation, including imaging tests and assessments of overall health. The CABG procedure typically involves several key steps. This procedure is done under general anaesthesia and usually takes three to six hours.

Once the patient is placed under anaesthesia, a chest incision is made to access the heart. The surgeon then identifies suitable grafts and attaches them to the coronary arteries, creating detours around the blocked segments. Once the grafts are in place, blood flow to the heart is restored, and the chest incision is closed.

Complications of CABG

CABG is generally a safe and effective procedure, but like any surgery, it carries the risk of complications. It's crucial to note that while these complications are possible, many patients undergo CABG without encountering serious issues. The risk of complications can be influenced by factors such as the patient's overall health, the presence of other medical conditions, and the skill of the surgical team. 

Possible complications associated with CABG include:

• Infection: The incision made in the chest during CABG can become infected. In severe cases, this can lead to mediastinitis, an infection of the tissues around the heart
• Bleeding: Bleeding can occur at the surgical site or within the chest. In some cases, this might require a return to the operating room to address the bleeding source
• Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE): Blood clots can form in the legs (DVT) and travel to the lungs (PE), posing a risk of serious complications
• Stroke: A stroke can occur if blood flow to the brain is disrupted during the surgery or due to the formation of blood clots
• Heart rhythm disturbances known as Arrhythmias: Irregular heart rhythms, such as atrial fibrillation, can occur after CABG. While often temporary, they may require medication or other interventions
• Graft failure: Graft Blockage or Narrowing can occur over time. Grafts used in the procedure may develop blockages or narrowing, requiring further interventions. Infections can also affect the grafts used in the procedure
• Allergic reactions: Some patients may experience allergic reactions to anaesthesia or medications used during or after the surgery

Like any surgical procedure, CABG comes with inherent risks. However, the potential benefits are substantial, ranging from symptom relief and improved heart function to an increased lifespan for individuals with severe CAD.

Recovery and rehabilitation

The post-operative period after CABG is crucial and patients are closely monitored in the intensive care unit (ICU) initially before being transferred to a regular hospital room. Pain management, medications to prevent infection, and encouragement of early mobilisation are essential components of the recovery process.

Patients usually stay in the hospital for about 6 to 8 days after a CABG procedure. Patients have a follow-up appointment typically 6 to 8 weeks after the procedure. Cardiac rehabilitation programs, including supervised exercise and education, are often recommended to promote long-term heart health. Most people make a full recovery within 12 weeks of the procedure.

Medication that patients are discharged with include: 

• Antiplatelet and anticoagulant medications: Medications such as aspirin and blood thinners are often prescribed to prevent blood clots and complications
• Cholesterol-lowering drugs: Statins may be prescribed to manage cholesterol levels and prevent further plaque buildup in the arteries
• Pain relief medications: Pain management is crucial during the recovery period. Medications will be prescribed to alleviate discomfort while ensuring that patients can participate in rehabilitation exercises

Long-term outcomes and follow-up

While CABG can provide significant relief and improve overall heart function, it is not a cure for CAD. Lifestyle changes, such as smoking cessation and dietary modifications, are often recommended to optimise the chances of a successful outcome. Long-term success depends on the patient's commitment to lifestyle changes, medication adherence, and regular follow-up with healthcare providers. Monitoring for potential complications and addressing any emerging issues promptly is crucial for maintaining optimal heart health.

Follow-up care after Coronary Artery Bypass Grafting (CABG) is crucial for ensuring a successful recovery and maintaining optimal heart health. Long-term management includes follow-up:

• Rehabilitation and exercise: Patients are encouraged to engage in gradual physical activity as they recover, starting with light walking and progressing to more vigorous exercises under the guidance of healthcare professionals. Participating in a cardiac rehabilitation program is also highly recommended. These programs typically include supervised exercise, education on heart-healthy lifestyle changes, and emotional support
• Dietary changes: A diet low in saturated fats, cholesterol, and sodium is essential for maintaining cardiovascular health. Dietary recommendations may be provided by a nutritionist or healthcare provider
• Lifestyle changes:
  • Smoking cessation: If applicable, quitting smoking is critical for improving long-term outcomes
  • Weight management: Maintaining a healthy weight through diet and exercise is important for heart health
  • Stress management: Strategies for managing stress, such as relaxation techniques or counselling, may be recommended
• Regular follow-up appointments: Patients should attend scheduled follow-up appointments with their cardiac surgeon and other healthcare providers to monitor overall health and address any concerns
• Preventive care: Preventive measures, such as influenza and pneumonia vaccinations, may be recommended to reduce the risk

By actively participating in post-CABG follow-up care, individuals can optimise their recovery and reduce the risk of future cardiovascular events. Open communication with healthcare providers and a commitment to heart-healthy living are key elements in the long-term success of CABG.

Summary

Coronary Artery Bypass Grafting stands as a cornerstone in the treatment of coronary artery disease, offering a lifeline to individuals grappling with compromised heart function. By understanding the anatomy of the coronary arteries, the development of coronary artery disease, and the purpose and process of CABG, individuals can make informed decisions about their heart health.

With ongoing advancements in medical technology and a holistic approach to postoperative care, CABG continues to be a vital tool in the fight against CAD, providing hope and improved quality of life for those in need.