The problem with heart-valve disease

PHOTO: The problem with heart-valve disease

Patients with increasing shortness of breath and palpitations may not necessarily be harbouring significant narrowing of their heart arteries. The problem with such patients could lie with their heart valves, as was the case in three patients discussed here.

Valve disease is less commonly recognised, given that the symptoms are more subtle and usually develop gradually. However, recognising valve disease is important if sudden death is to be prevented.

Mitral valve prolapse

Mr A, in his 40s, had chest pain, increasing shortness of breath on exertion and frequent irregular and fast heart beat.

He was found to have a tear in his left heart valve (the mitral valve or MV), which is located between the left upper and lower heart chambers. A segment of the supporting bands of tissue that anchor the edges of the valve to the heart muscle wall had been torn, resulting in it failing to close properly; the result was that blood was "leaking" back into the left upper chamber when the left lower chamber pumps blood out of the heart through the aortic valve (AV) into the aorta, the main artery supplying blood to the body.

Fortunately for Mr A, the damaged MV could be repaired by surgery. He did not need his heart valve replaced. After surgery, his left heart chambers, previously swollen, returned to normal size.

He had had a mitral valve prolapse (MVP), not uncommonly seen in younger individuals. In patients with this condition, excessive physical exertion can tear the mitral valve structure if it already has an inherited abnormality, which weakens the valve structure and makes it more susceptible to tearing.

MVP is the one of the commonest valve conditions with about 7 per cent prevalence in autopsy studies in the USA. Early detection can mean avoiding complications through the adoption of preventive measures.

Age-related valve disease

Mr B and Mr C, both in their 60s, had abnormalities in their AV, although each was of a different nature.

The AV is a one-way valve that prevents blood from flowing back into the heart once it is pumped into the aorta. The incidence of AV disease is rising, given the rise in life expectancy. In affluent societies and modern cities, AV disease is mainly the result of age-related degeneration.

Mr B was a fitness enthusiast who noticed a decrease in his exercise tolerance; his heart rate would rapidly rise whenever he started exercising.

A check showed his AV to be encrusted with calcium deposits accumulated over the years, and contributed partially by his long-standing consumption of calcium-fortified foods and calcium supplements.

His valve leaflets were extremely stiff, resulting in less blood being pumped through the severely narrowed opening of the AV, a condition called aortic stenosis; it is like having a pinhole at the opening of a tap.

Once the patient with significant AV disease has shortness of breath, chest pain or fainting spells, the risk of death within a few years is high if surgery is not done.

Mr B had his AV replaced with a bioprosthetic valve and will be able to resume regular exercise after a few months of recovery.

Mr C complained of breathlessness and chest pain over the last year. These episodes had become increasingly frequent in the last few weeks, and he was also near fainting occasionally.

His AV was found to be damaged, resulting in a failure of the aortic heart valve leaflets to close properly. In this condition called aortic regurgitation, there is a hole in the AV even when the valve is closed, causing blood to leak continuously from the aorta to the left lower heart chamber.

As a result, the volume of blood being pumped to the body decreases significantly, giving him breathlessness and near-fainting spells. The drop in blood volume being pumped to the body was so significant that it occasionally resulted in chest pain.

Based on the current American Heart Association guidelines, he was advised to undergo surgical valve replacement as there was a risk of sudden death.

Recognising heart-valve disease

Patients with heart-valve disease may have absolutely no symptoms until the condition becomes severe. As the symptoms tend to be subtle and progress gradually, patients may attribute their state to age-related changes rather than underlying disease. Adults with chest pain, dizzy spells with a sensation of feeling faint, increasing shortness of breath on exertion or palpitations (high heart rate or abnormal heart rhythms) should consider getting a heart assessment.

Those with heart-valve disease will have abnormal heart sounds (heart murmurs), which are detectable with a stethoscope. Those with a heart murmur should thus consider going for an ultrasound scan of the heart called an echocardiogram or ECG. This is easily available, cost-effective and safe.

While surgery has remained the choice of treatment for those with severe valve disease, newer and less invasive techniques have been developed in the last few years. Less invasive catheter-based procedures for severe MV leakage and severe aortic stenosis have been carried out on suitable patients who are either high-risk candidates for surgery or who refuse surgery.

Recent data from published studies shows that less invasive, catheter-based techniques (Transcatheter Aortic Valve Replacement or TAVR) are comparable to or may even be better than surgery for those with severe aortic stenosis. The CoreValveUS Pivotal trial had a one-year mortality of about 14 per cent for TAVR, compared to about 19 per cent for surgery.

However, one must be cognizant that TAVR may be more expensive than conventional valve replacement surgery. It also requires an experienced team, which is not always available, as the volume and experience are low in most centres.

Also, long-term data is largely unknown. Recent publications have shown that more than half of those who underwent TAVR had silent strokes; clinically recognisable strokes were seen in about 2 per cent of patients.

Nevertheless, less invasive techniques for valve treatment are a promising alternative, which may give better results as technology advances and doctors' level of experience increases.

Dr Lim is medical director at the Singapore Heart, Stroke & Cancer Centre. He is also editor-in-chief, Heart Asia (a journal of the British Medical Journal Publishing Group); chairman, scientific advisory board, Asia Pacific Heart Association; and honorary professor and senior medical adviser, Peking University Heart Centre.

This series is brought to you by Heart, Stroke and Cancer Centre.

It is produced on alternate Saturdays.

This article was published on May 17 in The Business Times.

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