Mitral Valve Regurgitation and Prolapse
The mitral valves help regulate the forward blood flow from the lungs and out of the heart’s left sided chamber. The mitral valve has two leaflets that open and close to allow normal blood flow in the left sided pumping chambers.
Causes of Mitral Valve Regurgitation and Prolapse
Mitral valve regurgitation occurs when part of one or both of the mitral valve leaflets do not come together properly, causing blood to leak backwards from the lower pumping chamber of the heart (the ventricle) into the upper chamber of the heart (the atrium). The blood normally flows from the lungs into the upper chamber, passes through the mitral valve, and then flows into the lower chamber (the main pump of the heart) and through the aortic valve and to the rest of the body.
Regurgitation or leakage occurs when the valve leaflets or doors of the valve do not come together or close properly. This allows these leaflet segments or doors to go backwards into the upper heart chamber (left atrium) instead of closing all the way, similar to a saloon door. The chordae which are similar to parachute strings support the leaflets or doors. These can elongate or rupture and cause the leaflets or doors to not coapt or close properly and also cause the leak of the valve. Some patients have a prolapsed valve which may or may not be leaking. The prolapse refers to a floppy valve.
When mitral valve regurgitation is severe, it can cause heart enlargement and heart failure. The backward flow of blood can cause the left atrium or upper heart chamber to enlarge in time and subsequently result in an abnormal heart rhythm (atrial fibrillation). If untreated, atrial fibrillation can result in the development of clots in the atrium that can lead to stroke. The treatment begins with treating severe mitral regurgitation with surgery as previously described. Once atrial fibrillation develops, multiple options are available including surgery, medications, electrical cardioversion and catheter-based or surgical ablation. Medical therapy also consists of placing patients on blood thinners or anticoagulation. Monitoring of blood levels of the blood thinner is extremely important to avoid the blood from becoming thick and clotting.
Surgical Procedure for Mitral Valve Regurgitation
Open heart surgery for mitral valve regurgitation usually requires opening your chest through the sternum (breast bone). At Baylor St. Luke’s Medical Center, our surgeons specialize in minimally invasive techniques to repair mitral valve regurgitation. A minimally invasive approach is done through small incisions between the ribs (sometimes called “keyhole” or “port access” surgery).
Mitral valve repair techniques include trimming loose tissue from the leaflets, re-suspension of the leaflets with new artificial chords or parachute strings, and an annuloplasty ring. This consists of inserting a ring around the valve to bring both of the leaflets or entire valve back to its normal position or size.
During most heart surgeries, including minimally invasive heart valve surgery, it is necessary to put the patient on heart and lung bypass. During heart and lung bypass, the bypass machine will take over the heart and lungs function by helping circulate and the blood as well as provide oxygen to the blood. Your heart will begin beating again once it begins to receive its own blood at the end of the procedure. Once your heart is weaned from bypass, your surgeon will check your repaired or replaced mitral valve to ensure that the leaflets are closing properly. Mitral valve repairs are checked for function by performing an intraoperative trans-esophageal echocardiogram (TEE) similar to that obtained prior to surgery. A normal appearing echocardiogram is highly predictive of a durable or lasting repair.
If necessary, a mitral valve replacement can also be performed with a minimally invasive approach. A mechanical or biological valve would be used. Mechanical heart valves are made from metal or carbon, and last longer than biological valves; however you will need to take blood-thinning medication for life. Biological heart valves are made from animal tissue (cow or pig). These valves last 15 to 20 years, but you may not need to take blood-thinning medication if you do not have atrial fibrillation. It is important to note that if your valve cannot be repaired, a mitral valve replacement will be performed at the time of the surgery. It is crucial that you leave the operating room with a normally functioning mitral valve.
Mitral Valve Leaflet Repair
There are essentially two well know approaches to mitral valve repair. One consists of trimming or resecting the mitral valve leaflets (RESECT) and the other preserving the mitral valve leaflets (RESPECT) and using artificial chordae. Both are equally effective and at times both are used concomitantly in the same patient. The cardiac surgeon uses a variety of techniques to repair the mitral valve. The “toolbox technique“ is usually applied. In other words, using multiple approaches, instruments and sutures to repair the valve depending on the location and the amount of damage the mitral valve may have suffered.
Surgeons may be able to repair and reconstruct your heart valve so that it does not need to be replaced with an artificial valve. As shown in Figures A and B, the loose prolapsed section of leaflet will be cut away (a “triangular” or quadrangular resection). In C and D, the edges of the leaflet next to this cut away section are joined and sewn together. In D, a special cloth covered metal ring is then sutured around the repaired valve to compress the leaflets together, adding support and stability to the repair. This is called a ring annuloplasty.
Tricuspid Valve Surgery
Some patients with mitral valve regurgitation who undergo mitral valve repair or mitral valve replacement may also need a tricuspid valve repair. The main indication would be if there is a significant leak in the tricuspid valve as well. There are times when the tricuspid valve does not have a significant leak but the valve itself is very dilated or enlarged and your surgeon may choose to repair it. This is a controversial subject in the field of cardiac surgery, but the surgeons at Baylor St. Luke’s Medical Center strongly believe that it should be repaired in order to improve your heart function and avoid a future tricuspid valve repair.
Some patients may present with isolated tricuspid valve regurgitation or leakage that may be severe. These patients may have symptoms of right heart failure which include shortness of breath, enlarged liver, ascites (fluid in the abdomen) and/or swelling of the legs. These patients may be candidates for a minimally invasive tricuspid valve repair.
Tricuspid valve surgery is performed with the heart lung machine although it can be performed with the heart beating.
Outlook after Mitral Valve Surgery
When waking up from the anesthesia in the recovery room, most patients will still have the breathing tube in place. We usually allow you to slowly wake up from the anesthesia in order to closely monitor your vital signs and response to the surgery. You will have in place two drainage tubes, a pacemaker wire and a pain pump. These will be removed within the first three days of surgery. The bladder catheter, which was inserted under anesthesia, will be left in place for 24 hours. Most patients are discharged from Baylor St. Luke’s Medical Center within three to five days after surgery.
Patients usually stay in the intensive care unit for the first day or two and then moved to the hospital telemetry unit for additional monitoring. You should be walking a day after surgery. Our rehabilitation team is also involved in your care. Most patients are discharged from Baylor St. Luke’s Medical Center within three to five days after surgery. The majority are discharged home although depending on their circumstances, some will require additional care and will be transferred to a specialty nursing facility or rehabilitation facility.
With minimally invasive heart valve surgery, patients generally experience less blood loss, less post-operative pain, and fewer infections than open sternotomy based procedures. All aspects of the recovery are faster. Your ability to perform the breathing exercises and ambulate (walk) will be easier and safer since the breastbone is not split. We will provide multiple measures for pain relief but keep in mind that pain is very subjective and individual. Our goal is to provide you and your family with the best experience under these stressful times.