Open heart surgery is an incision that is made through the sternum, otherwise known as the breastbone, which is then spread apart. This form of opening is called a full or median sternotomy. Following the operation, the breastbone is closed with stainless steel wires, and the skin is sutured shut.
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Due to the stretching of muscles, bone, and ligaments that occurs during surgery, pain is usually felt following the operation; however, the breast bone heals over time. The term open heart surgery is also referred to as traditional heart surgery. However, due to the advent of new, more efficient, and safer procedures, open-heart surgery can be performed with only small incisions that do not require wide openings.
What types of open-heart surgery exist?
According to the National Heart, Lung, and Blood Institute (NHLBI), coronary artery bypass grafting (CABG) is the most common type of open-heart surgery done in adults. This procedure involves a healthy artery or vein Bing grafted, or attached, to a blocked coronary artery. This grafted artery can bypass the blocked artery and supply blood to the heart. CABG is used to treat people who have severe coronary heart disease (CHD). Other forms of open-heart surgery include:
- Transmyocardial laser revascularization (TMR), which is used to treat angina. If TMR is done alone, the procedure may be performed through a small opening. The surgeon uses lasers to form small channels through the heart muscle and into the left ventricle.
- Heart valve repair or replacement, which is used to fix a set of leaflets that control the opening of valves. If they become stuck or fused this can impede blood flow through the valve. In the absence of a correctly functioning leaflet blood can leak back into the heart chambers, rather than flowing in the intended direction toward the arteries. Valves are replaced with synthesized or biological alternatives. Biological alternatives are formed from pig, cow, or human heart tissue and may also incorporate some synthetic material.
- Arrhythmia treatment; in the failure of therapeutic relief offered by medicine, open heart surgery of this form may be used to implant a pacemaker or an implantable cardioverter-defibrillator (ICD). The device generates low-energy electrical pulses that control the heart rhythm. An ICD is a small device that is connected to the heart and monitors the heartbeats for dangerous arrhythmias. If an arrhythmia is sensed, a small electrical impulse is generated to restore a normal heart rhythm.
- Aneurysm repair: aneurysms are generated in the walls of arteries causing them to bulge. This bulge can occur if the artery wall weakens; the pressure generated from blood moving through the artery or heart causes the weekend area to bulge. Over time, an aneurysm can rupture, causing fatal bleeding inside the body – they may also split into one or more layers of the artery wall which can cause bleeding along them. Repairing an aneurysm involves the placement of a patch or graft to replace the weakened section of the artery or heart wall.
- Heart transplant, which is performed in patients who have end-stage heart failure. Heart failure occurs when the heart is damaged or weakened. The term end-stage denotes the severity of the condition, indicating all other treatments have failed to restore heart function.
- Ventricular assist devices and total artificial hearts: a ventricular assist device is a mechanical pump that supports heart function in patients with weakened hearts. This is usually implanted in cases where heart failure that is not responsive to treatment is present, or the patient is on a waiting list for a heart transplant. A total artificial heart replaces the two ventricles of the heart
On-pump and off-pump open heart surgery
There are typically two different methods of performing open-heart surgery; on-pump and off-pump. On-pump open heart surgery is a time restrictive procedure that is performed while the heart has been completely stopped. The blood supply must be provided to the body when the heart is stopped and therefore surgeons will use a cardiopulmonary bypass machine, which is also referred to as the heart-lung machine or the pump. It functions as an artificial circulation system that performs a function of the heart and lungs.
Cannulas are placed into the heart to drain blood to the pump where it is purified and put back into the patient; this allows temporary immobilization of the heart. At the end of the procedure, the heart is restarted and once it reaches a threshold for satisfactory function, the cardiopulmonary bypass machine is disconnected after the cannulas are removed.
On-pump open heart surgery has a small risk of death and other complications. These complications may include kidney or liver failure, cognitive dysfunction, stroke, and bleeding. Despite the risk combat the development of new technology continues to increase the efficacy and safety of cardiopulmonary bypass machines.
Off-pump open heart surgery is a relatively newer method of performing open-heart surgery. As the name suggests, the open-heart surgery procedure is performed while the heart is still beating, and in the absence of the cardiopulmonary bypass machine.
Despite the absence of cannulas and pipes for the machine, use of an artificial circulatory fluid, unexcepted manipulation of the aorta, this technique involves complex attachment of grafts to the heart while it moves and is filled with blood. This lack of stabilization can increase the risk of error; however, specialized devices can mechanically stabilize the targeted area of the heart, enabling suturing to occur on a much more immobile surface.
Despite the constant motion which introduces the likelihood of error in the procedure, the risk of complications from off-pump open heart surgery is also low in a low-risk patient. However, this technique requires high levels of experience. The benefits of off-pump open heart surgery mitigate against the same complications seen in on-pump open-heart surgery, with overall lower complication rates. These include decreased risk of stroke and cognitive dysfunction, alongside the decreased risk of atrial fibrillation and organ dysfunction.
What are the risks associated with open-heart surgery?
All forms of surgery on the heart including open heart surgery have risks. These include:
- Bleeding
- Reaction to the anesthetic
- Infection, fever, swelling, and other associated signs of inflammation
- Damaged to heart, lungs, kidney, and liver tissue
- Arrhythmia
- Stroke, which can cause long term as well as short term damage
- Death
Other side effects may include memory loss or other forms of neurocognitive dysfunction such as difficulty concentrating or thinking clearly. These neurological problems are more likely to affect older patients and women and often improve within 6 to 12 months of surgery.
In general, the risk of complications is increased if heart surgery is performed in an emergency context. This includes for example, during a heart attack. The risk of complications is also increased in cases where other comorbidities are present such as kidney and lung disease, or peripheral artery disease.
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