Repairing those heart valves

By Smriti Daniel

Despite dazzling breakthroughs in medical technology, it can still be difficult to improve on nature. Consultant cardiac surgeon, Dr. K. Kesava Dev knows this to be true, which is why he is an advocate of repairing heart valves instead of replacing them. Of course it’s not always possible – for instance, if the damage to your valves is too severe you might not qualify. If you do, however, valve repair will allow a patient a significantly higher quality of life, says Dr. Dev.

While mechanical and tissue substitutes do exist, they have their own limitations such as a shorter lifetime or require that patients take anticoagulants every day. “Ultimately, what it means is that valve substitutes are not perfect,” says Dr. Dev. “You can get rid of your symptoms but you have to deal with other issues and this is why valve repair has come up.”

Understanding the human heart

The heart is often compared to a pump that drives circulation. The right side receives the exhausted blood that has already delivered its nutrients and oxygen to the rest of the body, and then pumps it through the lungs where the blood is revitalised. Here, CO2 is removed and oxygen added to the blood. The blood is then drawn through the left side of the heart, which pumps this enriched blood out into the body.

Each half is composed of an atrium that receives the blood and a ventricle that pumps the blood back out. There are also four valves, with two on each side – the pulmonary and mitral valves on the left and the tricuspid and aortic on the right. The valves are made up of ‘leaflets’ and are anchored by elastic chords known as chordae tendinae; the chordae help open and close the valves. When functioning properly, the valves allow blood to flow in only one direction.

Disease can affect valves in two basic ways, explains Dr. Dev: regurgitation and stenosis . The first occurs when a valve doesn’t close tightly enough, allowing blood to leak backwards into the heart chamber rather than flowing forward into the heart or the relevant artery. In stenosis, valves thicken, stiffen or simple fuse together, thereby preventing the smooth flow of blood.

Heart valve disease is either congenital (a child is born with it) or rheumatic (following rheumatic fever in childhood) or degenerative (it can develop later in life). However, whatever the damage is attributed to, leakage and backflow can result in unpleasant consequences for patient. “All four valves can be affected by various diseases,” explains Dr. Dev, adding that in the case of the mitral valve in particular, repair is often a better option than replacement. Located in the left atrium, the mitral valve receives newly oxygenated blood from the lungs.

Repair vs. replacement

When the valve leakage becomes significant, it can cause shortness of breath, breathlessness during exercise, or congestive heart failure, says Dr. Dev, adding that timely treatment is essential to prevent permanent heart and lung damage. He and his team rely on several manoeuvres to repair damaged valves. If they are floppy or flailing, the surgeon might remove a particular segment or re-suture it. He might also need to work with the chordae that anchor the valves if these are stretched or broken. They can be shortened to hold the valve down more firmly or replaced with substitute chordae. “There are other ways in which we can augment the leaflet,” says Dr. Dev, explaining that they can use a patch of the patient's own tissue, or snip away a distended part of the valve. “At the end of it we put a fabric ring that will be seated there [at the base of the valve] that will make sure that the valve repair will last for a long time,” he says.

In contrast to a direct replacement, this process requires more skill and patience on the part of the surgeon. As Dr. Dev explains, “it’s not 100% science, it’s a little bit of an art as well.” So why attempt a repair when a replacement is possible? It boils down to giving the patient a chance to live a healthier life. When patients are given a prosthetic mitral valve, their treatment must extend well into their life post-surgery. Anti-coagulants are prescribed to ensure the blood stays thin and travels easily through the new valve.

These must be taken every day without fail, emphasises Dr. Dev. Infection of the valve can occur, which is dangerous and difficult to treat, and there is an elevated risk of stroke. In addition, monthly blood checks are a must, to see if the consistency of the blood is in the right range. If it is too thin, you can start to bleed from your gums; if it is too thick the valve can get jammed or blocked, leading to serious complications. Finally, artificial tissue valves will wear out - on average they last between 10 to 15 years – and will then need to be replaced in another surgery.

Repair on the other hand, plays to the natural strengths of the body. Not only is there no daily regimen of anti-coagulants but the long term prognosis is better. “It has been shown in several studies that patients with valve repair live longer than those with valve replacements,” reveals Dr. Dev. The surgery is possible in patients of any age and gender, but not all damaged valves are suitable for repair. “It’s good for everybody. The only danger is if you come late in the disease...if you wait too long, the damage is too severe and it becomes too difficult to repair it,” he says.

Post surgery: Protecting your valve

Surprisingly, one of the biggest dangers to your new valves can come in the dental chair. A heart infection called infective endocarditis (IE) is “life threatening and dangerous,” says Dr. Dev, adding that even the treatment is painful. You must tell your dentist if you have had IE before or have a prosthetic valve, so that you can be given antibiotics to cope with any bacteria that enter your bloodstream via your gums.

Another common cause of IE is simply poor dental hygiene. To prevent this serious infection, you need to take good care of your teeth, brushing regularly and visiting a dentist to deal with any gum infections or tooth decay that may develop.

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