Mitral Valve Repair: Types and Surgical Risks

The mitral valve is the heart valve which is present on the left side of the heart separating and regulating the blood flow between the left atrium and ventricle. Blood which gets oxygenated in the lungs enters the left atrium and flows to the ventricle through the mitral valve. After this, the valve closes when the left ventricle contracts to prevent backflow into the atrium, allowing blood to enter the aorta (the large artery leaving the left ventricle) and supply the rest of the body.

Structural changes in the mitral valve can result in mitral stenosis or narrowing with inadequate blood flow across the valve, or to mitral regurgitation with loose valves that do not close properly, allowing backflow of blood from the ventricle to the atrium. Both conditions require correction depending on the severity of the problem.

Mitral valve repair is a surgical procedure done to correct the structural defect to restore normal blood flow in the heart. An alternate procedure, mitral valve replacement can also be performed where the entire valve is replaces with prosthetic material.

Mitral Valve Repair Procedures

There are several types of procedures which can be performed:

• Annuloplasty: This is done for patients with a leaking heart valve (mitral regurgitation) where the individual valve leaflets do not oppose and close appropriately. This involves surgically tightening the ring around the valve.
• Valvuloplasty: This is done for patients with a narrowed valve (mitral stenosis). This involves passing a balloon through the valve leaflets and inflating the balloon to allow more room for blood to flow through.
• Cord Repair: The valve is held securely through strings or cords of heart tissue which reach the valve from the walls of the ventricle. Occasionally, these cords are lose causing mitral regurgitation and need to be replaced or repaired to hold the valve in place.

Surgical Approach

The procedure can be done through multiple surgical approaches:

• Open heart surgery: This involves the traditional surgery where the individual is placed under anesthesia and the chest is opened by a sternotomy, an incision through the sternum (breastbone). The patient is places on a heart-lung machine while the beating of the heart is stopped to facilitate handling the heart for the procedure. Recovery takes longer and a large scar is visible on the front of the chest.
• Minimally invasive heart surgery: In this, the heart is accessed by making several incisions on the side of the chest to allow entry of surgical instruments. The patient is then placed on a heart lung machine for the duration of the procedure. Recovery takes a shorter time, there is less pain and better cosmesis is achieved
• Catheter based procedure: This involves inserting a thin wire (catheter) through a peripheral artery to reach the heart valve. Another wire bearing an instrument at the tip, like a balloon or a clip (mitral clip) is threaded to reach the valve to carry out valvuloplasty or reshape the valve. This has the advantage of not requiring general anesthesia, takes a shorter time to conduct with rapid recovery.

Robot assisted heart surgery is a novel type of surgery where the surgeon takes the help of robotic arms to carry out surgery. This improves precision. Robotic surgery is available in certain advanced centres.

The choice of surgical approach is made based on the type of procedure planned and the surgeon’s expertise with it. It is definitely better to undergo open heart surgery from an experienced surgeon than to demand minimally invasive surgery from someone inexperienced.

Risks and Side Effects of Surgery

• Bleeding
• Blood clot formation and risk of dislocation to rest of the body
• Stroke arising from a dislodged blood clot or from poor blood supply to the brain during surgery
• Arrhythmiasor abnormal heart rhythm
• Heart attack from reduced blood supply to the heart tissue during surgery
• Inadequate correction or further damage to the heart valves
• Infection of the valves and blood stream
• Death

Prognosis and Post-Surgical Care

The prognosis depends on the initial condition and success of surgery. Following mitral valve repair, routine activities can be resumed in a graded fashion. Periodic follow up is required to monitor the condition of the heart and some medications may need to be continued. Healthy food, moderate exercise and smoking cessation are beneficial to promote heart health.

References:

1. What is heart valve disease? National Heart, Lung, and Blood Institute
2. What is heart surgery? National Heart, Lung, and Blood Institute