Surgery for Mitral Valve Disease
Videos of Mitral Valve Repair |
Surgical Video of Mitral Valve Repair |
Echocardiogram of Posterior Leaflet Prolapse |
Echocardiogram of Anterior Leaflet Prolapse |
Mitral valve surgery involves going on the heart-lung machine (cardiopulmonary bypass) and stopping the heart. The heart is then opened and the mitral valve repaired or replaced. The heart is closed and allowed to resume beating. After heart function returns, the patient is removed from the heart-lung machine.
Mitral Valve Repair: Why We Do It
There are many reasons why a mitral valve repair is superior to a mitral valve replacement. All artificial heart valves used for replacement have disadvantages.
Tissue valves
Tissue valves (usually made from cow or pig tissue) will wear out over time. This may not be important for an older person who will die before the valve wears out, but it is a problem for a younger person because they will have to have another heart operation to replace the worn out tissue valve, usually in about ten years.
Mechanical heart valves will last indefinitely
Mechanical heart valves will last indefinitely, meaning that no further surgery will be required. There are two major problems with mechanical valves.
Blood clots can form that can break off
Blood clots can form that can break off and go to the brain (causing a stroke) or to other organs or limbs. In some cases, the blood can clot on the valve itself, causing it to malfunction. Blood thinners such as warfarin must be taken to prevent the blood clots from forming. This causes quite a change in lifestyle. The patient must have blood tested regularly to make sure the blood is not too thick or too thin, and the medicine must be taken every day and in just the right dose.
Bleeding complications
People on warfarin can develop bleeding problems, and as patients get older, this becomes a significant risk, such as if they fall or have an ulcer. If some other surgery or procedure is required, the warfarin must be stopped to prevent bleeding during the operation, and this puts the patient at risk.
The risk of a blood clot problem with a mechanical valve is 1-2% per year, and the risk of a bleeding problem is 1-2% per year. For a younger person who is 40 who lives to be 80, that means there is a 40-80% chance of a bleeding problem and a 40-80% chance of a blood clot problem over their lifetime. People who have physically demanding jobs with an increased risk of injury, such as construction workers, may be at increased risk for bleeding while on warfarin.
Finally, warfarin causes birth defects when it is taken during pregnancy, so this is a problem for young women who wish to have children.
Deterioration of heart function
When the mitral valve is replaced, the normal function of the valve is eliminated. The mitral valve does more than just keep blood flowing in one direction. It is part of the entire structure of the heart and left ventricle, and when the valve is replaced, it is not uncommon for the left ventricle function to deteriorate over time. Long-term results in terms of quality of life and life expectancy are better if a valve replacement can be avoided.
Primary Factors Determining the Likelihood of a Successful Repair
There are two primary factors determining the likelihood of a successful repair:
- The condition of the valve and heart at the time of the surgery. If the valve or the heart is in very poor condition, there is a lower likelihood of a repair. This is why surgery is sometimes recommended earlier, before deterioration begins. Rheumatic mitral valve disease can be difficult to repair due to scarring and calcification. The vast majority of degenerative mitral valve disease and ischemic mitral valve disease can be repaired although some surgeons feel that the Barlow's form of degenerative disease is harder to repair.
- The experience and skill of the surgeon.
The following quotes are taken from the ACC/AHA 2006 Guidelines for the Management of Patients with Valvular Heart Disease:
- "…cardiologists are strongly encouraged to refer patients who are candidates for complex MV repair to surgical centers experienced in performing MV repair."
- "MV repair should be able to be achieved by experienced surgeons for the majority of patients with degenerative disease and ischemic valve disease, and patients should be referred to surgeons expert in repair.
Generally speaking, experienced surgeons should be able to repair 90% of the mitral valves with degenerative or ischemic disease.
Results
Because the results of mitral valve repair have improved over the last several decades in terms of durability of repair, quality of life, and life-expectancy, and because the risks of surgery have diminished, repair is being offered much earlier than before. Mitral valve surgery for regurgitation can be offered to patients with no symptoms who have the following conditions:
- Evidence of heart dysfunction or dilatation or abnormally high pressures in the arteries to the lungs. Normally, the heart can pump out around 60% of the blood within it. This is called the ejection fraction. When the heart deteriorates, the pumping ability decreases and the ejection fraction falls. Mitral valve repair may be indicated in the patient with no symptoms who develops a decline in ejection fraction.
- When the heart contracts this is known as systole. Echocardiography can measure the diameter of the left ventricle in systole, and if it is greater than 40mm, this represents dilatation and surgery may be indicated, even if there are no symptoms.
- If the blood pressure in the arteries to the lungs exceeds 40mmHg, this may be an indication for surgery in an asymptomatic patient. If a patient with severe mitral regurgitation and no symptoms develops atrial fibrillation, surgery can be considered because fixing the mitral valve may cause the atrial fibrillation to go away.
- There is a high likelihood that the valve can be repaired Finally, even if the patient has no symptoms, normal heart function, no heart dilatation, normal blood pressure in the arteries to the lungs, and no atrial fibrillation, surgery may still be considered if they have severe mitral regurgitation if it looks like the valve can probably be repaired rather than replaced. This is why it is so important to have your case evaluated by a surgeon who is experienced and skilled in mitral valve repair.