Definition and Overview
Mitral valve repair or replacement surgery is a medical procedure performed for the treatment of a leaking mitral valve, a heart valve with dual flaps located between the left atrium and left ventricle. Also known as the bicuspid or left atrioventricular valve, it plays an important role in controlling the flow of blood.
A normal mitral valve opens up during diastole (a brief period during which the ventricles are relaxing and filling) due to the increased blood pressure from the left atrium. As it opens, the blood flows into the left ventricle, after which the valve closes again. When a mitral valve malfunctions, it causes blood to leak backwards through it. Thus, during the contraction of the left ventricle, blood flows abnormally in two directions. Any disruption in the mechanism of the mitral valve can result in this problem. Thus, a damaged mitral valve has to be repaired. If it is beyond repair, it has to be replaced.
Who Should Undergo and Expected Results
Mitral heart valve repair or replacement surgery is beneficial for patients who are suffering from damaged or malfunctioning mitral valves. These include those who suffer from mitral insufficiency and mitral valve regurgitation. It is also an ideal treatment for patients whose mitral valves are narrowed; a medical condition called mitral stenosis.
Problems with the mitral valve may be caused by several factors. The following are possible causes of mitral insufficiency or mitral valve damage:
Myxomatous degeneration, which is a genetic weakness of the mitral valve tissue
Mitral valve prolapse, in which the cords supporting the mitral valve stretch, causing the valve’s leaflets to bulge into the left atrium every time the left ventricle contracts. It is a common heart defect that should be treated with a mitral valve prolapse repair.
Trauma to the chest
A previous heart attack
Cardiomyopathy, or abnormality in the heart muscle
Congenital heart defects, or heart valves that are already damaged at birth
Prolonged use of certain medications, such as ergotamine
Radiation therapy focused on the chest area
Mitral regurgitation may cause the following symptoms:
Dyspnea or shortness of breath
Not all patients with weak or damaged mitral valves experience symptoms since the condition progresses slowly. Thus, many patients remain undiagnosed for several years. Nevertheless, it is still strongly recommended that they undergo the procedure regardless of whether they experience symptoms or not. The earlier mitral valve repair surgery is performed, the lower the patient’s risk for complications. On the other hand, if the condition is left untreated, patients may be at risk of heart failure, pulmonary hypertension, and atrial fibrillation.
Once the mitral valve is repaired or replaced, normal blood flow through the heart is restored. This resolves all symptoms and significantly reduces the patient's risk of serious heart problems.
How is the Procedure Performed?
Nowadays, minimally invasive mitral valve repair/replacement is more commonly performed as an alternative to open-heart surgery. This type of procedure is safer, has a reduced risk of complications, and ensures the patient’s faster recovery. Patients also experience less bleeding and less pain.
Depending on the cause of the problem and its severity, damaged mitral valves are either repaired or replaced. The best mitral valve repair surgeons agree that repairing the valve, instead of replacing it, provides better outcomes for patients, especially in terms of preserving heart function and ensuring patient’s long-term survival. Between the two, the repair procedure has a lower risk of complications. Also, while patients who undergo mitral valve replacement require blood thinners after the procedure, those who have had their mitral valves repaired do not. Both procedures, however, can be done in a minimally invasive manner.
Minimally invasive mitral valve repair surgery can be performed using different methods, including percutaneous mitral valve repair (also known as transcatheter mitral valve repair) and robotic mitral valve repair.
For a minimally invasive mitral valve repair procedure, the patient is placed under general anaesthesia. The surgeon then makes up to 4 small cuts in the chest or groin area, instead of one large incision in the chest. These small incisions are used to insert special surgical instruments that are used to perform the procedure, including a thin catheter that is inserted percutaneously. If the cut is made in the groin area, the catheter is inserted through the groin artery.
In a robot-assisted procedure, the surgeon makes 2 to 4 cuts in the chest, each one around 1-2 centimetres in size. The procedure is then performed using a clinical robotic surgical system such as the da Vinci Surgical System. During both types of procedure, imaging technology is used, which provides surgeons with a magnified, high-definition 3D view of the surgical site.
A mitral valve repair is performed by:
Trimming, shaping, and rebuilding the flaps that close and open the mitral valve
Tightening the valve by sewing a ring made of metal, cloth, or tissue around it
A mitral valve replacement, on the other hand, is performed by removing the old valve and replacing it with an artificial one. Artificial valves are either made of:
Biological materials, such as human or animal tissue – Biological valves last for 10-15 years or even longer and do not require patients to take blood thinners
Man-made materials, such as carbon or titanium – Man-made valves last longer, but patients need to take blood-thinning medications for the rest of their lives
Mitral valve repair/replacement surgery may take two to four hours.
Possible Risks and Complications
The risks of a mitral valve repair procedure are significantly fewer if performed using minimally invasive methods. These include:
Adverse reactions to medications or anaesthesia used
Infection that may affect other organs, such as the lungs, kidneys, or the bladder
Infection due to the new valve (if the valve is replaced)
Poor wound healing
Mitral valve repair recovery is also shorter for those who undergo a transcatheter or percutaneous procedure instead of an open-heart procedure.
Armstrong GP. “Mitral regurgitation.” Merck Manual. http://www.merckmanuals.com/home/heart-and-blood-vessel-disorders/heart-valve-disorders/mitral-regurgitation
Acker MA, Parides MK, Perrault LP, et al. “Mitral valve repair versus replacement for severe ischemic mitral regurgitation.” N Eng J Med. 2014; 370: 23-32. http://www.nejm.org/doi/full/10.1056/NEJMoa1312808#t=article
Verma S, Mesana TG. “Mitral-valve repair for mitral-valve prolapse.” N Engl J Med 2009; 361:2261-2269. http://www.nejm.org/doi/full/10.1056/NEJMct0806111
Silaschi M, Chaubey S, Aldalati O, et al. “Is mitral valve repair superior to mitral valve replacement in elderly patients? Comparison of short- and long-term outcomes in propensity-matched cohort.” Journal of the American Heart Association. 2016;5:e003605. http://jaha.ahajournals.org/content/5/8/e003605