Researchers at National, Heart, Lung, and Blood Institute (NHLBI), Maryland, have developed a novel technique that prevents the obstruction of blood flow, a common fatal complication of transcatheter mitral valve replacement (TMVR).
The new method, called LAMPOON, may increase treatment options for high-risk patients previously ineligible for heart valve procedures. The study has been published online in the Journal of the American College of Cardiology.
TMVR is used to treat mitral valve stenosis, a narrowing of the valve that restricts blood flow into the main pumping chamber of the heart. It also treats regurgitation, which occurs when the valve leaks and causes blood to flow back through the valve. If left untreated, these conditions can cause pulmonary hypertension, heart enlargement, atrial fibrillation, blood clots, and heart failure.
For elderly or weak patients, TMVR offers a less invasive alternative to open heart surgery.
During TMVR, doctors replace the mitral valve by delivering an artificial valve through a long, thin, flexible, catheter, through blood vessels and into the heart.
However, in more than 50 percent of patients the heart’s anatomy may lead to complications. The heart valve leaflet may be pushed back blocking the blood flow. This is known as left ventricular outflow tract (LVOT) obstruction, a common and the most life-threatening complication of TMVR.
“These patients have a failing mitral valve, are not able to undergo open heart surgery, and are now rejected as candidates for TMVR because of the very high risk of the left ventricular outflow tract obstruction,” said study author Jaffar M. Khan, M.D., clinician at NHLBI in a press release.
To increase the availability of TMVR for this subset of patients, the researchers at NHLBI and Emory University developed the LAMPOON procedure that makes an intentional incision at the anterior mitral leaflet to prevent left ventricular outflow tract obstruction.
In the LAMPOON procedure, the operator inserts two catheters through the patient’s groin, and then through the blood vessels until it reaches the heart. The doctor then uses an electrified wire the size of a sewing thread woven through the catheter to split open the leaflet. At that point, the patient is ready to undergo TMVR.
“Surgeons cut out the leaflets when they replace valves. They can do it, because they have cut open the chest and the heart and can clearly see the problem. LAMPOON is designed for patients who need a new mitral valve, but can’t, or may not want to undergo open heart surgery,” said Khan.
The study conducted between June 2017 and June 2018 enrolled 30 patients considered at high risk for surgical valve replacement and at prohibitive risk of LVOT obstruction during TMVR.
All patients survived the procedure and 93 percent reached the 30-day survival mark, which compares favorably to a 38 percent reported with other methods, reported the National Institute of Health.