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Encyclopedia > Aortic valve replacement

Aortic valve replacement is a cardiac surgery 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; the valve can either become leaky (aortic insufficiency / regurgitation) or partially blocked (aortic stenosis). 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. Cardiac surgery is surgery on the heart, typically to treat complications of ischemic heart disease (e. ... The aortic valve is one of the valves of the heart. ... Aortic insufficiency (AI), also known as aortic regurgitation (AR), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. ... Aortic valve stenosis (AS) is a heart condition caused by the incomplete opening of the aortic valve. ... In percutaneous aortic valve replacement (PAVR), a synthetic valve is transported to the heart through a small hole made in groin. ... Catheter disassembled In medicine, a catheter is a tube that can be inserted into a body cavity, duct or vessel. ... Cardiac surgery is surgery on the heart, typically to correct congenital heart disease or the complications of ischaemic heart disease or valve problems caused by endocarditis. ...

Contents

Types of Heart Valves

There are two basic types of artificial heart valve, mechanical valves and tissue valves.


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 homograft - a human aortic valve -- can be implanted. Homograft valves are donated by patients and harvested after the patient dies. 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 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 and is used primarily in children. The Ross procedure (or pulmonary autograft) is a cardiac surgery operation where a diseased aortic valve is replaced with the persons own pulmonary valve. ... An allograft is a transplanted organ or tissue from a genetically non-identical member of the same species. ... The pulmonary valve (or pulmonic valve) is the semilunar valve of the heart that lies between the right ventricle and the pulmonary artery and has three cusps. ...


Mechanical valves

Mechanical valves are designed to outlast the patient, and have typically been stress-tested to last several hundred years. 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. Warfarin (also known under the brand names of Coumadin, Jantoven, Marevan, and Waran) is an anticoagulant medication that is administered orally or, very rarely, by injection. ...


Valve selection

Tissue valves tend to wear out faster with increased flow demands - such as with a more active (typically younger person). Tissue valves typically last 10-15 years in less active (typically elderly) patients, but wear out faster in younger patients. When a tissue valve wears out and needs replacement, the person must undergo another valve replacement surgery. For this reason, younger patients are often recommended mechanical valves to prevent the increased risk (and inconvenience) of another valve replacement.


Surgical Procedure

Aortic valve replacement is most frequently done through a median sternotomy, meaning the chestbone is sawed in half. 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. Median sternotomy is a surgical procedure in which a vertical inline incision is made along the sternum, after which the sternum itself is divided, or cracked. This procedure provides access to the heart and lungs for surgical procedures such as heart transplant, corrective surgery for congenital heart defects (CHDs... The pericardium is a double-walled sac that contains the heart and the roots of the great vessels. ... A Heart-Lung Machine (upper right) in a Coronary Artery Bypass surgery (CABG) Cardiopulmonary bypass (CPB) is a technique that temporarily takes over the function of the heart and lungs during surgery. ...


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 (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. The transesophageal echocardiogram (TEE) is used over the transthoracic echocardiogram (TTE) whenever better, more detailed images of the heart are needed by the cardiologist. ...


Hospital Stay and Recovery Time

Immediately after aortic valve replacement, the patient will frequently stay in a cardiac surgery 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 is a surgical procedure used to correct some aortic valve disorders. ... It has been suggested that this article or section be merged with Heart valve prosthesis. ... Wikipedia does not yet have an article with this exact name. ...

External links

  • ValveReplacement.com - Forum for valve replacement patients and their relatives
  • Mitral Valve Repair at The Mount Sinai Hospital

  Results from FactBites:
 
Aortic Stenosis (2208 words)
Aortic stenosis becomes hemodynamically significant when the area is about 1cm2 to 0.8cm2 (as noted above in the above discussion of the area of the valve orifice which can be classified as to severity of stenosis), as the systolic flow is impeded across the valve.
In the aortic position, a bioprosthetic valve is the valve of choice in most elderly patients because the rate of valve tissue degeneration is considerably lower than in younger age groups and the probability of valve tissue failure in patients over 70 is 20% at 10 years.
In the younger age group, mechanical prosthetic valves tend to be used because most patients wish to minimize the probability of reoperation due to valve dysfunction and because of the accelerated fibrosis-calcification in biologic prosthetic valves in children and young adults.
  More results at FactBites »

 
 

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