Mitral Valve Replacement
Your mitral valve is two little flaps of tissue that control the flow of blood from the upper chamber to the lower chamber on your heart's left side. If it's damaged and repair is an option, it is nearly always preferable to have the valve repaired rather than replaced. But if it's too badly damaged to be repairable, then it will be advisable to give serious consideration to having the valve replaced. Replacement is much more likely in cases when the valve is blocked (stenotic) rather than leaky (regurgitant) or when the damage was caused by rheumatic fever.
If you are diagnosed with a mitral valve too badly damaged to be repairable, your surgeon will evaluate the specifics of your situation and weigh the risks of surgery against the risks of managing the disorder with medication and other nonsurgical treatments. Sometimes, it may be possible to manage your symptoms with lifestyle changes and/or medication. And sometimes it may be preferable to wait a while and have your valve replaced at the same time that another cardiac procedure is undertaken. But often it will be advisable, for a valve badly enough damaged not to be repairable, to replace the defective valve before symptoms of congestive heart failure begin to occur.
Should you and your surgeon decide the time is right for surgery, keep in mind that the cardiac surgeons at Dartmouth-Hitchcock (D-H) have considerable expertise in all the proven options for replacing (as well as repairing) damaged mitral valves. Surgical replacement of the mitral valve is fairly common.
There are several ways to replace a damaged mitral valve. If your valve is judged to require replacement, the two primary matters your surgeon will consider are what kind of replacement valve to use and which surgical approach will work best.
There are two primary kinds of replacement valves. Factors such as your age and the overall state of your health will affect which kind is most appropriate:
- Mechanical valves are made of very durable artificial materials, such as titanium, carbon, polyester, Dacron or Teflon. They are typically very long-lasting; however, use of a mechanical valve requires patients to take blood-thinning medication (often referred to by the brand name of Coumadin) for the rest of their lives.
- Biological valves, also known as tissue valves or bioprosthetic valves, are made of animal tissue, often from a pig or a cow. They do not usually necessitate the use of blood-thinning medication; however, biological valves typically last only 10 to 20 years, so a second valve replacement operation may be required in the future.
The appropriate surgical approach will depend on such factors as how damaged your valve is and the overall state of your health. Though open surgery is the most common option for replacing mitral valves, your surgeon will determine which of the following procedures is most appropriate in your particular situation:
- Open-heart surgery to replace a defective mitral valve involves making a 7" to 9" incision over the middle of the sternum, or breastbone, then dividing the sternum to allow access to the heart. In some cases a less invasive option, involving a slightly smaller sternal incision, is possible. Then the damaged valve is removed and the replacement valve is sutured, or sewn, into place. It will be necessary to stop your heart from beating during the procedure, so the operation can be performed on a motionless and bloodless field; while your heart is stopped, a device known as a heart-lung bypass machine will take over your heart's function and maintain your circulation.
- Minimally invasive surgery involves making one or two much smaller incisions (typically 2" to 4") in the side of your chest, between your ribs. Then the procedure is performed by inserting a tiny camera and long, thin surgical instruments through your tissues to your mitral valve. Minimally invasive surgery typically requires the use of a heart-lung bypass machine. Although it is typically not the preferable option for replacing mitral valves, in circumstances when it is appropriate this approach avoids the need to split the sternum and open the entire chest, so recovery may be faster.
It is important to keep in mind that every medical choice involves a trade-off between risks and benefits—whether it is to undergo surgery, take medication, or even just carefully monitor a condition (an option known as "watchful waiting").
In the case of a damaged mitral valve, deciding whether to have it replaced involves balancing the risks involved in any heart surgery against the risk of continuing to manage the disorder with medication and other nonsurgical treatments, which may result in the development of congestive heart failure. There is a very high likelihood that patients who don't have surgery to fix a severely damaged mitral valve will within 10 years experience serious adverse effects (such as congestive heart failure, an abnormal heart rhythm, or a stroke), and some will die.
The risks involved in mitral valve replacement surgery are usually much lower than those involved in medical therapy. A given patient's risk will vary—depending on such factors as age, overall health status, and how well their heart is functioning—but the average mortality, or risk of death, from mitral valve replacement surgery is from 3% to 5%. Such surgery is also associated with a 2% to 4% risk of a blood clot that causes a serious stroke. In addition, about 2% of patients may later require an artificial pacemaker. And any surgical procedure involves a very small risk of other complications, such as infection. Patients who smoke can reduce their risk of complications if they stop smoking at least two to four weeks before their surgery (it is best not to quit immediately before having heart surgery, however, because when people stop smoking they often have short-term bronchorrhea, or excess secretions in their respiratory tract, which makes them cough a lot—and coughing a lot when you have just had heart surgery is not a good idea).
The benefits of successful surgery are significant. The overwhelming majority of patients, once they recover, feel better than they did before the operation and are able to resume any activities they wish to engage in.
A typical open-heart procedure takes from four to six hours, in some cases up to eight hours; patients are then maintained under general anesthesia for an additional four to six hours. If their heart is performing well and there is no excess bleeding, they can emerge from anesthesia and have their breathing tube removed. Most patients stay in the ICU until midday of the day after their procedure; if they continue to do well, the drainage tubes in their chest can then be removed and they can be moved to a regular hospital bed later that day. The typical hospital stay ranges from four to seven days. At that point, the vast majority of patients are able to go home, with support from the visiting nurse service, though about 15% to 30% may need to spend some time in a rehab facility for more extensive rehabilitation. After discharge, patients are advised not to drive for about three weeks and not to lift anything heavier than 5 lbs. for about six weeks. Beyond that point, they can resume whatever activities they wish to.
Patients tend to be surprised at how easy it is to control their pain. By the second day after their operation, most patients are comfortable without intravenous pain medication, taking only oral painkillers, and the overwhelming majority are discharged home on just Tylenol or Motrin.
In cases when minimally invasive surgery is appropriate, both the length of the operation and the recovery period are typically shorter.
Page reviewed on: Jun 26, 2015
Page reviewed by: Jock McCullough, MD
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