Coronary Bypass Surgery
Coronary artery bypass grafting (CABG) is used to treat blocked coronary arteries. When there is a narrowing or blockage in the coronary arteries the heart is starved of oxygen and this can result in chest tightness (angina), shortness of breath or a heart attack. Coronary artery bypass surgery involves bypassing these blockages with other veins or arteries from the chest, arm or leg to give the heart a new blood supply.
In triple bypass surgery the blockages in the coronary arteries are bypassed using arteries and veins from the chest wall and legs to provide a completely new blood supply.
Symptoms
Coronary artery disease occurs when there are obstructions in the coronary arteries.
This is caused by numerous factors including genetics, lifestyle, diabetes, smoking, high blood pressure and high cholesterol. As the arteries become narrowed and the heart is starved of oxygen, symptoms can occur that include chest tightness, shortness of breath or even a heart attack where a portion of the heart muscle dies from lack of oxygen.
Angina is classically described as chest pain, but it is actually usually not painful. Most patients describe it as a heaviness in the chest or a tightness and there can also be pain in the left arm, the shoulder, the jaw or the abdomen.
Some people do not experience any pain or tightness with coronary artery disease and can even suffer a so-called silent heart attack. This is more common in women and diabetics.
Diagnosis
The typical path towards surgery would often start with the general practitioner where a patient presents with chest tightness after they walk up a hill, which settles when they stop walking. The GP may arrange a stress test where the patient exercises on a treadmill while the heart is monitored either with ultrasound (echocardiography) or an ECG to look for signs of oxygen starvation (ischaemia). If the stress test is positive, and there are signs of oxygen starvation, then the patient will be referred to a cardiologist, who will perform a coronary angiogram.
This is a test where the cardiologist threads a needle through the wrist (radial artery) or the leg (femoral artery) and inserts a small tube into the arteries of the heart. Contrast dye is injected into the coronary arteries and an x-ray picture is taken. This picture provides a very clear description of any narrowings (stenoses) or blockages in the coronary arteries.
The angiogram will determine the severity of the coronary disease and if the patient needs surgery or alternative medical therapies.
Who needs this procedure?
Treatment options for patients with coronary artery disease can include non invasive medical therapy such as perscription medication, or percutaneous treatment called coronary artery stenting performed by an interventional cardiologist. Alternatively patients can be referred for coronary artery bypass surgery with a specialist cardiothoracic surgeon.
The decision between these three treatment options depends on the severity of the coronary artery disease, the patient factors and the age of the patient. Typically, patients with one or two discrete blockages can be effectively treated with either medical therapy or with stenting.
Patients with three-vessel disease, diabetes, very complex diffuse coronary artery disease and those who present with an impaired heart function are usually referred to the surgeon for coronary artery bypass surgery.
It has been shown in multiple large, randomised trials over the last 40 years that there is an improvement in survival after surgery in these subsets of patients.
What is involved?
Coronary bypass surgery is performed under general anaesthetic through a vertical incision down the middle of the breastbone (sternum) to expose the heart; this is also known as a sternotomy. The patient is connected to a heart-lung machine which pumps blood through the body whilst the heart is stopped to perform the bypasses.
Dr Bassin may perform this operation ‘off pump’ with the heart still beating in certain cases. This is technically more challenging, but can reduce the chance of a stroke during surgery for high-risk patients.
The bypasses are formed from veins and arteries in the body where removing them does not impair the blood supply to that area. The most common bypass grafts are taken from behind the chest wall from the same incision used to expose the heart – these are the left and right internal mammary arteries (LIMA and RIMA). The other common bypass grafts are taken from the legs – the long saphenous vein, and an artery in the arm – the radial artery.
The bypasses are generally 15-20 cm long and completely bypass any obstructions in the coronary arteries by providing a completely new blood supply, rather than just addressing the blocked area. This means that if any further disease occurs in the first section of the coronary artery, it will not cause any issues because there is a new blood supply from the bypass downstream. This is one of the key differences between bypass surgery and coronary stents – stents only open an individual blockage and don’t treat any future disease that might occur.
What is the recovery like?
The operation takes approximately 3-4 hours and you will wake up in intensive care later that day or the next morning. Small tubes to drain any residual fluid from around the heart will be placed in your neck, as well as intravenous lines, to sample blood and administer medications. These tubes and lines will be removed after 1-2 days and then you will be transferred to the ward to continue your recovery.
Once on the ward, the goal is to monitor your blood pressure and heart rate and ensure adequate mobilisation. We work very closely with our nurses, physiotherapists and occupational therapists to work on breathing exercises and functional mobilisation. Every patient is different and the assistance is tailored to your needs. Many patients are discharged home after a week but there is a significant number of patients, particularly the elderly who find it easier to transition home after a short stay in a rehabilitation hospital.
Once at home, patients are encouraged to take plenty of walks and to generally take it easy. Your body will let you know what it is capable of and there is no need to push it during this recovery period.
For the first 6 weeks there are precautions to be taken whilst the bone is healing. Lifting should be limited to 3 kg and patients are encouraged to sleep on their back. Any activity that requires heavy use of the arms is generally discouraged.
You will probably feel ready to go back to work after 4-6 weeks and a complete recovery is achieved by 3 months.
What are the benefits and risks of this procedure?
Coronary Bypass Surgery improves the blood supply to the heart using natural veins and arteries from the body. This reduces the symptoms of angina and chest pain, reduces the chance of a heart attack and improves survival.
Coronary bypass surgery is one of the most common and studied operations in the history of medicine. In its current form it has been performed since the 1970s with excellent results. We have continued to improve the safety of surgery but there are still risks. For patients who are otherwise well the risks of surgery include: death (1%), stroke (1%), significant wound infection (1%), kidney injury (2%) and blood transfusion (25%). The risk can be higher if patients have other co-morbidities including advanced age, previous heart disease or stroke, lung disease or having undergone cardiac surgery previously.
Dr Bassin will explain these risks to each patient in person and how they pertain to their specific condition.
When can I drive?
You may drive 4 weeks following surgery, according to the national guidelines.