The heart functions to pump blood to and from the lungs to receive oxygen and then pump the oxygenated blood through the body. Blood flows through the four chambers of the heart through heart valves that open and close as the chambers contract and relax. The aortic valve separates the left ventricle and the aorta--the artery that sends blood through the body. Damage to the aortic valve can cause it to become narrow or leaky, leading to life-threatening conditions. Aortic valve replacement surgery, an open-heart surgical procedure, treats these problems by replacing the damaged valve, as described by the Society of Thoracic Surgeons.
Stroke
Surgeons and patients can choose between two types of valves to replace the aortic valve: biological heart valves made from animal tissue and mechanical valves made of synthetic materials. Mechanical valves provide the advantage of durability whereas biological valves need replacement approximately every 10 years, according to the Texas Heart Institute.
Blood tends to stick to the mechanical valves, promoting the formation of blood clots. These blood clots can dislodge from the valve and travel through the blood vessels resulting in a stroke. Patients receiving mechanical valves must therefore take blood thinning medications for the rest of their lives to help prevent stroke.
In addition, because doctors stop the heart during the aortic valve replacement procedure, they utilize a heart-lung machine to keep oxygenated blood flowing through the body. The machine promotes blood clotting that can lead to a stroke; therefore blood thinning medications are given during surgery.
Bleeding
Aortic valve replacement surgery requires taking blood thinning medications, such as warfarin, to prevent blood clots from forming. When used during the surgical procedure it increases the risk of an increased loss of blood. Long-term use of blood thinners increases the risk of bleeding complications following surgery. The University of Maryland Medical Center reports a 1 percent risk of bleeding per year.
Infection
Any surgical procedure that requires opening the body carries a risk for infection. Aortic valve replacement surgery requires the heart to be exposed by opening the chest cavity. This can introduce infectious bacteria into the heart. An infection within the lining of the heart, a condition known as endocarditis, can occur. A study published in October 2004 by J.P.A. Puvimanasinghe and associates in "Heart and Education in Heart" reveals the incidence of endocarditis as 3.9 percent for patients receiving mechanical valves and 3.2 percent for patients receiving biological valves.
Arrhythmia
Properly functioning heart valves help the heart to beat rhythmically. Arrhythmia, the occurrence of an abnormal heartbeat, can result due to aortic valve replacement surgery. A study published by M. Banach and associates in the December 2007 "Journal of Thoracic Cardiovascular Surgery" indicates atrial fibrillation as the most common complication following cardiac surgery. Atrial fibrillation occurs when the upper chambers of the heart quiver instead of beating effectively. This prevents the atria from completely emptying which promotes the formation of blood clots that can lead to a stroke.
Death
As with any major surgery, especially open heart surgery, death can occur. "Scientific American" reports the mortality due to an aortic valve replacement surgery as approximately 2 percent.
References
- The Society of Thoracic Surgeons: Aortic Valve
- University of Maryland Medical Center: Aortic Valve Replacement Surgery
- "Heart and Education in Heart"; Comparisons of Outcome after Aortic Valve Replacement; J.P.A. Puvimanasinghe et al; October 2004
- "Journal of Thoracic Cardiovascular Surgery": Predictors of Atrial Fibrillation; M. Banach et al; December 2007
- Scientific American: What is Aortic Valve Replacement Surgery?
