A Release Valve

Nonsurgical options for patients with pulmonary valve conditions

BY CARIN MOONIN

Patients with congenital heart disease—such as tetralogy of Fallot, pulmonary atresia or pulmonary valve stenosis—often undergo several surgeries over the course of their lives to implant and/or replace a conduit or heart valve. Yet transcatheter pulmonary valve replacement (TPVR) is minimally invasive, safe and has been shown to be a viable, longer-lasting alternative to open surgery—and possibly even multiple procedures.

After TPVR, most patients are able to resume their normal daily activities within the week. This is quite a difference from the four to six weeks of aftercare and activity restrictions generally required to recover from open heart surgery.

Since December 2017, John F. Rhodes, M.D., a pediatric and adult congenital interventional cardiologist, has been performing TPVR—along with other interventional cardiology measures—to revise right ventricular outflow tracts. Rhodes has recently returned to MUSC as the operations director for the MUSC Children’s Health Congenital Heart Center and as an interventional specialist for children and adults with congenital heart disease.

A brief overview of TPVR

Although transcatheter aortic valve replacement (TAVR) has been performed since the early 1990s, it has only been since about 2000 that transcatheter procedures have been used for pulmonary valve concerns. The lag is largely a numbers issue: aortic valve disease (often age-related) is simply more common than pulmonary valve disease (often congenital).

In 2000, Philipp Bonhoeffer applied the TAVR model toward treating congenital heart disease. This led to what became Medtronic’s Melody transcatheter pulmonary valve, which treats narrowed or leaking pulmonary valve conduits between the heart’s right chamber and the lungs. It consists of a bovine jugular vein valve sutured within a platinum iridium frame. Currently, the Melody Valve (Medtronic; Minneapolis, MN), along with the Edwards SAPIEN XT transcatheter heart valve (Edwards Lifesciences; Irvine, CA), made from cobalt-chromium and bovine pericardial tissue, are both used for TPVR. In both devices, the valve is sewn onto the stent apparatus and crimped onto a balloon.

The minimally invasive procedure can be performed on adults and pediatric patients. Contraindications are rare and include inadequate vascular access, pulmonary tract outflow not large enough to sustain a strong cardiac output, metal allergies or vascular structures that may interfere with placement.

The TPVR process

TPVR is a nonsurgical, endovascular procedure, typically done in MUSC’s cardiac catheterization laboratory. Usually the catheter is started through the patient’s femoral vein, but occasionally the jugular vein is used if there are concerns with venous access or the size and shape of the femoral vein. The catheter goes through the right ventricle and into the lungs; a support wire is used to move the valve over the wire into the right ventricular outflow tract and deploy the valve using the balloon.

After the procedure, patients are typically kept overnight for evaluation and an echocardiogram to assess placement. Healing time is approximately two to three days; as it is not a surgical procedure, there is little that needs to heal aside from the small access point of the femoral vein.

“The rate of any complications is very low—less than three percent,” says Rhodes. “The main risk is bleeding, infection or calcification to the existing graft.”

Outcomes appear positive

Follow-up data for patients who have had TPVR compare favorably with those for patients who have undergone surgical valve replacement. Rhodes believes much of that is due to less of the body’s inflammatory response with transcatheter procedures versus open surgery.

He also feels encouraged that the data suggest TPVR will further improve on outcomes. “Surgical valve replacement [in patients who have had prior valve replacement surgeries] has been shown to last about seven to ten years at most,” says Rhodes. “We’re hoping TPVR will be more like ten to twenty years.” Rhodes would like to see TPVR used for patients who have not had previous surgeries—the “native outflow” tract; he believes response will be even better for that patient subset.

Going forward

“This is profound for the patient,” adds Rhodes. “When you do an operation and fix the pulmonary valve, it usually doesn’t last a lifetime. Many patients have about two or three operations before they even turn 18. But what if we could prevent major surgeries, and the patient could improve both physical and psychological recovery? This is revolutionizing medicine. It’s amazing technology, and I can’t wait to see where we go next.”