Aortic valve replacement is an open-heart surgical procedure for treating a diseased aortic valve. Wearing out due to age is the most common cause of aortic valve disease, according to Thoralf M. Sundt, M.D., member of The Society of Thoracic Surgeons. The options for replacing the aortic valve include using a human or animal donor valve, a mechanical valve or the patient's own pulmonary valve. The type of valve replacement received depends on patient lifestyle, preference, age and other medical conditions.
Pulmonary Valve Transplantation
Pulmonary valve transplantation, also referred to as the Ross procedure, involves removal of the patient's own pulmonic valve. This valve is sewn into the position of the aortic valve. The next step requires a donor pulmonic or prosthetic valve be put in place of the original pulmonic valve. According to Michael H. Crawford, M.D., author of Current Diagnosis and Treatment in Cardiology, the patient's pulmonic valve is used to replace the aortic valve because it can handle the high pressure and stress associated with blood flow coming from the heart's left side. The major drawback to pulmonic valve transplantation is the amount of surgery involved. Although it is a very technical procedure with successful results, not every hospital has the resources to facilitate it, according to Crawford.
Bioprosthetic Valve Replacement
Bioprosthetic valve replacement involves using a heterograft or homograft to replace the aortic valve. A heterograft is made from the aortic valve or pericardium of a cow or pig. The major advantage of a heterograft is the minimized risk of blood clot formation after the procedure. However, a big drawback to the heterograft procedure is that the valve will fail in 50 percent of patients after 15 years, explains Tirone E. David, M.D., author of "Aortic Valve Replacement with Stentless Porcine Bioprostheses," published in the Journal of Cardiac Surgery. Candidates for a bioprosthetic heterograft valve replacement are more elderly people in which the valve life expectancy is greater than that of the patient.
Bioprosthetic homograft valves are taken from human donors and considered more durable than heterografts. However, the availability of these valves is low due to most organ donors having their entire heart used for heart transplants as opposed to it being pieced out.
Mechanical Valve Replacement
Mechanical valve replacement offers increased durability compared to bioprosthetic transplantation. However, lifelong anticoagulation drug therapy is needed to prevent blood clots from forming in the heart after the procedure. If the medication is not taken, clots will form around the mechanical valve and eventually lead to stroke. Furthermore, the valve may become stuck open or closed shut, causing reduced blood flow from the heart. Physician-author Michael H. Crawford explains that mechanical valves are usually used in younger patients who require the long-term durability offered by these implants.
References
- The Society of Thoracic Surgeons: Aortic Valve
- "Aortic Stenosis"; Current Diagnosis and Treatment in Cardiology; Michael H. Crawford, M.D., 2009
- "Journal of Cardiac Surgery"; Aortic Valve Replacement with Stentless Porcine Bioprostheses; Tirone E. David, M.D.; July 2007
