Progressnotes - October/November 2012
- About MUSC Health
The mitral valve allows passage in a one-way direction from the upper left chamber of the heart (left atrium) to the lower left chamber of the heart (left ventricle). Two crescent-shaped flaps of tissue called leaflets open to allow blood to pass from the left atrium into the left ventricle during a contraction and then close between contractions to prevent blood in the left ventricle from flowing back into the left atrium. The chordae tendineae are fibrous strings that attach the leaflets to the ventricle and control its opening and closing, ensuring a tight fit. According to Mario A. Castillo-Sang, M.D., Assistant Professor in the Division of Cardiothoracic Surgery at MUSC, who specializes in minimally invasive cardiac surgeries, the cords and leaflets act like “a parachute with the cords (parachute strings) holding the leaflets (canopy)—if you break one or more cords, then there is regurgitation of blood or leakage.” The main symptoms of mitral regurgitation (ie, the flow of blood back into the left atrium) are fatigue and shortness of breath upon exertion and, in severe cases, even at rest.
Not everyone who has mitral regurgitation requires an operation as the severity of the regurgitation can be mild, moderate, or severe. Candidates for surgery include patients with severe mitral regurgitation who are manifesting symptoms, who have no symptoms but who are showing silent damage to the heart on echocardiography, and who are without symptoms and without silent damage to the heart but who are deemed to have over a 90% chance of having a successful mitral repair (as opposed to replacement).
Many surgical techniques can be used for mitral valve repair, a procedure that has as much art as it has science. At MUSC, mitral valve repairs are performed in a standard approach via median sternotomy and via right minithoracotomy, all dictated by the adequacy of the approach for each individual patient. According to Dr. Castillo-Sang, what is new about right minithoracotomy is “not the access through the right chest but the much smaller incision.” The smaller incision reduces the likelihood of infection, speeds recovery, and causes less scar tissue around the heart. Because it does not require the lower sternum to be separated, right minithoracotomy does not disrupt the breathing mechanism, as can happen after the lower sternum has been split in two.
A preferred technique at MUSC for minimally invasive mitral valve surgery via right minithoracotomy is the “Leipzig Loop” technique. Originated in Leipzig, Germany, by Professor Frederick Mohr, one of the pioneers in mitral valve repair, this technique conserves the original tissue of the mitral valve leaflets and seeks to replace the ruptured cords that caused the regurgitation using Gore-tex® loops. “You leave everything the patient has, but you are reinforcing and putting the Gore-tex loops into sites where the cords were ruptured to make them competent again,” explains Dr. Castillo-Sang. In essence, the Gore-tex loops are used to restring and reinforce the chordae tendineae to improve closure of the mitral valve, preventing regurgitation.
This article originally appeared in the November 2013 issue of Progressnotes.
Minimally Invasive Repair of Degenerative Mitral Valve Regurgitation (surgery video):