Cardiovascular surgery is performed by a cardiac surgeon on the heart or the heart’s major vessels. This surgery is usually conducted to prevent heart disease or failure, correct cardiac disease, treat the complications related to heart disease, or transplant a heart. A doctor may perform open heart surgery or minimally invasive surgery, and may stop the heart, or leave it pumping.
During open heart surgery, the chest is opened and the heart is operated upon. “Open” describes the chest, not the heart, which may or may not be opened depending on the nature of the surgery. This type of surgery has been practiced since the 19th century, though procedures have changed greatly. Minimally invasive surgery can also be used in many cases.
Traditionally, most cardiovascular surgery would require cardioplegia, or stopping the heart, and connecting the patient to a heart-lung machine. This machine circulates blood and oxygen through the lungs and the rest of the body in the heart’s stead. After the surgery, the heart must be restarted and returned to normal beating. Now it is also possible to conduct an off pump, beating heart cardiovascular surgery, in which the heart does not need to be stopped and a heart-lung machine is not necessary. This often allows doctors to make smaller incisions and minimizes the risk of complications related to stopping the heart.
Coronary artery bypass grafting (CABG), or simply coronary bypass, may use a heart-lung machine or be off-pump. This cardiovascular surgery is usually required when there is a blockage or narrowing of the coronary artery due to coronary artery disease. Doctors must create a new vessel to get oxygen-rich blood to the myocardium, or muscle of the heart. To replace the blocked artery, they graft a section of vein or artery from another part of the patient’s body, usually from the leg or chest.
Angioplasty, or balloon angioplasty, can also treat symptoms of coronary artery disease and patients with atherosclerosis, or blocked arteries. In this minimally invasive cardiovascular surgery, the doctor inserts a guide catheter through an artery, usually the femoral artery in the leg, and guides it through the site of the blocked artery. Then a balloon catheter is then pushed along the guide catheter’s path. When it reaches the site of the blockage, the balloon is inflated, which expands the vessel and compresses the plaque accumulation. The balloon catheter is then removed, sometimes leaving behind a stent to keep the artery open.
Heart valve surgery is necessary when a heart valve needs to be replaced or repaired. This can mean a heart valve has trouble closing fully, called insufficiency or regurgitation, and allows blood to leak back through the valve the wrong way. Insufficiency can be caused by degeneration or tearing of the valve’s supporting structures or of the valve itself. A heart valve may also fail to open fully, called stenosis, and not allow enough blood through to the next chamber. This is usually caused by a hardening of the valve.
Repairing a valve often involves cutting, sewing, and reinforcing different parts of the valve to make it tighter. A valve may also be replaced with a prosthetic valve. A patient may receive a mechanical valve, which is made of man-made materials, or a biological valve, which is donated from another human, a pig, or a cow. Mechanical valves often require lifetime use of anti-coagulants, or blood thinners, while biological valves usually do not require long-term use of these medications. The surgery involves stopping the heart and making an incision through the aorta or heart to access the valve.
Cardiac replacement is a last resort surgery when no other treatments can save the heart. The replacement heart is donated by a cadaveric donor after passing tests for infection and receiving approval from the donor’s family. If the United Network for Organ Sharing (UNOS) accepts the heart, it will be given to the first person on the waiting list. The waiting list is determined by many factors, amongst them blood type, length of wait, and size.