By Dr Wong Ningyan, Associate Consultant, and Assoc Prof Yeo Khung Keong, Senior Consultant, Department of Cardiology, NHCS
Our heart contains four valves that play a vital role in maintaining blood circulation and keeping blood flowing in the correct direction. When one or more of the heart valves malfunctions, they can cause heart valve disease.
Patients with mild heart valve disease can be monitored without treatment and continue to lead a long and healthy lives. For patients with severe heart valve disease, they are at risk of developing infections and complications such as heart failure and stroke. Heart valve problems are mainly categorised into three types, namely leaky valve or regurgitation where valve does not close properly; stenosis where valve’s leaflets thicken, stiffen or fuse; and atresia where valve does not open at all.
Normal heart (left) versus a heart with mitral regurgitation (right)
Mitral Regurgitation – What is it?
The mitral valve, one of the four valves, is located between the left heart chambers (left atrium and left ventricle). Mitral regurgitation is a condition in which the mitral valve
leaflets do not close tightly. When this happens, blood flows backward from the left ventricle into the left atrium. The heart must then work harder to push blood through
the body, which can cause fatigue, shortness of breath and heart failure. There are several causes of mitral regurgitation and these include deterioration of valve tissue, conditions
that weaken the heart muscle and congenital valve abnormalities.
For mild cases, treatment may not be necessary but the severity of leakage needs to be monitored with ultrasound scans of the heart (echocardiograms). For more severe cases, treatment is required. In the past, we only had surgery or medications to treat mitral regurgitation. Surgical treatment involves either repairing or replacing the mitral valve. Mitral valve repair preserves the patient’s own valve, while replacement (performed when repair is not possible) replaces the damaged valve with an artificial one. Both methods require open-heart surgery and a heart-lung bypass machine is used to take over the function of the heart while it is being worked on. Medications can be used to help make symptoms more manageable but they do not treat the defect in the mitral valve itself.
For some patients who have many other medical problems or are very ill, open-heart surgery may be considered as high risk. A minimally invasive procedure called the MitraClip procedure is the alternative option.
The MitraClip device is attached directly to the mitral valve, without opening the chest. To access the mitral valve, a catheter (a long, flexible tube) is guided through a large vein from the leg to reach the heart. The MitraClip device is then passed through the catheter and clipped to the mitral valve, allowing the valves to close more completely and therefore helps to restore normal blood flow through the heart.
Patients will be admitted one day before the procedure, and stay for another two to three days. The procedure is performed in the cardiac catheterisation laboratory with echocardiographic and x-ray guidance while the patient is under general anaesthesia. The whole procedure takes approximately three to four hours. Complex cases may require a longer procedure time and hospital stay.
The MitraClip device is then passed through the catheter and clipped to the mitral valve to properly close the valve.
Thus far, the MitraClip has been used in over 50,000 patients worldwide. It has an excellent safety profile and demonstrates consistent results in terms of symptoms relief, reduction in mitral regurgitation as well as hospitalisation for heart failure.
At the NHCS, more than 90 patients have undergone the MitraClip therapy since it was made available in Singapore in 2011.
The MitraClip procedure has its risks but the advantage is that it is less invasive than an open-heart surgery and requires a shorter recovery time. It gives hope to patients who are at high or prohibitive surgical risk, such as those who are elderly and frail, with multiple comorbidities (e.g. lung or kidney conditions) or have previous open-heart surgery.
Who Is Suitable for MitraClip Therapy?
Patients with moderate to severe mitral regurgitation and require mitral valve intervention will be referred initially to a cardiac surgeon. If they are deemed unsuitable for surgery, referral will be made to a MitraClip physician. Further clinical examination and investigations will be performed. With this information, the MitraClip team comprising a cardiologist experienced in the MitraClip procedure, an echo cardiologist, a heart failure specialist and a cardiac surgeon, will meet and discuss if patient is suitable for this procedure.
All illustrations in this article are courtesy of Abbott Structural Heart.
This article is from Murmurs Issue 32 (Sep – Dec 2018). Click here to read the full issue.