Aortic valve replacement

Aortic valve replacement is a surgical procedure in which a patient's aortic valve is replaced by a different valve. The aortic valve can be affected by a range of diseases and require aortic valve replacement. The valve can either become leaky (regurgitant or insufficient) or stuck partially shut (stenotic). Aortic valve replacement currently requires open heart surgery. As of 2006, percutaneous aortic valve replacement is being researched, which allows the implantion of valves using a catheter without open heart surgery.
Contents

• 1 Types of Heart Valves
o 1.1 Mechanical, Tissue and Homograft Valves
o 1.2 Durability
• 2 Surgical Procedure
• 3 Hospital Stay and Recovery Time
• 4 Surgical Outcome and Risk of Procedure
• 5 See also

Types of Heart Valves
Mechanical, Tissue and Homograft Valves
There are two basic types of artificial heart valve, mechanical valves and tissue valves. Tissue heart valves are usually made from animal tissues, either animal heart valve tissue or animal pericardial tissue. The tissue is treated to prevent rejection and to prevent calcification.
There are alternatives to animal tissue valves. In some cases a human aortic valve can be implanted. These are called homografts. Homograft valves are donated by patients and harvested after the patient expires. The durability of homograft valves is probably the same for porcine tissue valves. Another procedure for aortic valve replacement is the Ross procedure or pulmonary autograft. The Ross procedure, named after Dr. Donald Ross - one of the pioneers in cardiac surgery in the U.K., is surgery where the aortic valve is removed and replaced with the patient's own pulmonary valve. A pulmonary homograft (pulmonary valve taken from a cadaver) is then used to replace the patients own pulmonary valve. This procedure was first used in 1967.
Although mechanical valves are long-lasting and generally only one surgery is needed, there is an increased risk of blood clots forming with mechanical valves. As a result, mechanical valve recipients must generally take anti-coagulant drugs such as warfarin for the rest of their lives, which effectively makes them borderline hemophiliacs.
Durability
Mechanical valves are designed to outlast the patient, and have typically been stress-tested to last several hundred years. Tissue valves will typically last between 10-15 years. In younger patients, tissue valves will wear out faster. For this reason, older patients are often recommended tissue valves.
Surgical Procedure
Aortic valve replacement is most frequently done through a median sternotomy, meaning the chestbone is sawed through. Once the pericardium has been opened, the patient is placed on cardiopulmonary bypass machine, also referred to as the heart-lung machine. This machine takes over the task of breathing for the patient and pumping his blood around while the surgeon replaces the heart valve.
Once the patient is on bypass, an incision is made in the aorta. The surgeon then removes the patient's diseased aortic valve and a mechanical or tissue valve is put in its place. Once the valve is in place and the aorta has been closed, the patient is taken off the heart-lung machine. Transesophageal echocardiogram (or TEE, an ultra-sound of the heart done through the esophagus) can be used to verify that the new valve is functioning properly. Pacing wires are usually put in place, so that the heart can be manually paced should any complications arise after surgery. Drainage tubes are also inserted to drain fluids from the chest and pericardium following surgery. These are usually removed within 36 hours while the pacing wires are generally left in place until right before the patient is discharged from the hospital.
Hospital Stay and Recovery Time
Immediately after aortic valve replacement, the patient will frequently stay in a Cardiothoracic Intensive Care Unit for 12-36 hours. After this, the patient is often moved to a lower-dependency unit and then to a cardiac surgery ward. Total time spent in hospital following surgery is usually between 4 and 10 days, unless complications arise.
Recovery from aortic valve replacement will take 1-3 months if the patient is in good health. Patients are advised not to do any heavy lifting for 6-8 weeks following surgery to avoid damaging the sternum (breast bone) while it heals.
Surgical Outcome and Risk of Procedure
The risk of death or serious complications from aortic valve replacement is typically quoted as being between 1-5%, depending on the health and age of the patient, as well as the skill of the surgeon. Older patients, as well as more fragile ones, are sometimes inelegible for surgery because of elevated risks.
See also
• Aortic valve repair
• Mitral valve repair
Mitral valve repair
From Wikipedia, the free encyclopedia
Mitral valve repair is an open heart procedure performed by cardiothoracic surgeons to treat stenosis (narrowing) or regurgitation (leakage) of the mitral valve. The mitral valve is the "inflow valve" for the left side of the heart. Blood flows from the lungs, where it picks up oxygen, and into the heart through the mitral valve. When it opens, the mitral valve allows blood to flow into the heart's main pumping chamber called the left ventricle. It then closes to keep blood from leaking back into the lungs when the ventricle contracts (squeezes) to push blood out to the body. It has two flaps, or leaflets.
The techniques of mitral valve repair include inserting a cloth-covered ring around the valve to bring the leaflets into contact with each other (annuloplasty), removal of redundant/loose segments of the leaflets (quadrangular resection), re-suspension of the leaflets with artificial (Gore-Tex) cords, and more recently the "bow-tie" procedure where a single stitch allows to repair the valve non-surgically.
Occasionally, the mitral valve is abnormal from birth (congenital). More often the mitral valve becomes abnormal with age (degenerative) or as a result of rheumatic fever. In rare instances the mitral valve can be destroyed by infection or a bacterial endocarditis. Mitral regurgitation may also occur as a result of ischemic heart disease (coronary artery disease).
A history of mitral valve repair
The development of the heart-lung machine in the 1950s paved the way for replacement of the mitral valve with an artificial valve in the 1960s. For decades, mitral valve replacement was the standard operation for a patient with a diseased mitral valve.
There are significant downsides to an artificial mitral valve. Infection of the prosthetic valve can occur, which is very dangerous. Patients with mechanical heart valves are required to take blood thinners for the rest of their lives and are at risk for bleeding complications. Artificial tissue valves will last between 10 and 15 years, placing the patient at risk of a second operation to replace the valve. The risk of stroke with an artificial mitral valve is significant (approximately 1 % per year).
In the last two decades, some surgeons have embraced surgical techniques to repair, rather than replace, the mitral valve. These techniques were pioneered by a French heart surgeon, Dr. Alain F. Carpentier, who published a landmark paper in the mid 1980s entitled The French Correction.
See also
• Aortic valve repair
• Cardiac surgery