A transcatheter pulmonary valve can be successfully and safely implanted within a failed bioprosthetic pulmonary valve, yielding good short-term hemodynamic results. The findings, from the largest study of the strategy to date, were published online December 4, 2012, ahead of print in Circulation: Cardiovascular Interventions.

Investigators led by Matthew J. Gillespie, MD, of Children’s Hospital of Philadelphia (Philadelphia, PA), looked at 104 patients scheduled for implantation of a Melody valve (Medtronic, Minneapolis, MN) in a failed surgical bioprosthesis in the pulmonary position at 8 centers between April 2007 and January 2012.

Implantation 100% Successful

Melody valve implantation was successful in all cases attempted (n = 100), with no procedure-related serious adverse events or deaths. After implantation, right heart hemodynamics improved significantly from baseline, with postimplant gradients less than 25 mm Hg in all but 2 patients (table 1).

Table 1. Effect of Treatment on Hemodynamics

Abbreviations: RV, right ventricle; PA, pulmonary artery.

Follow-up information was available for 95 patients (91%) at a median of 12 months. There were 2 deaths, both unrelated to Melody implantation. Two patients experienced endocarditis at 13 and 18 months after the procedure. In addition, stent fractures were identified by fluoroscopy in 2 patients at 13 months, translating to an estimated 95% rate of freedom from fracture at 2 years. Neither fracture resulted in significant hemodynamic dysfunction or required reintervention.

The authors acknowledge that due to the relatively short follow-up, the functional longevity of the Melody valve remains to be seen. “[M]ore data will be necessary to assess the risks and benefits of [transcatheter implantation] in the management of patients with postoperative [right ventricular outflow tract] dysfunction, but the findings of this preliminary multicenter experience . . . are encouraging,” they conclude.

Almost half of the patients had combined regurgitation and stenosis as the presenting mechanism for bioprosthetic valve failure, with more than three-quarters exhibiting moderate-to-severe regurgitation.

Melody valves were implanted in 10 different types of surgical valves, with the Perimount device (Carpentier-Edwards, Irvine, CA) and Hancock valved conduit (Medtronic) accounting for the majority (74%). The median nominal bioprosthetic valve size was 23 mm (range, 16-29 mm), and the median duration from surgical implantation to percutaneous replacement was 9.1 years (range, 0.6-33.0 years).

Technical Considerations Key

In a telephone interview with TCTMD, Ziyad M. Hijazi, MD, MPH, of Rush University Medical Center (Chicago, IL), said the valve-in-valve technique “looks like it works for most or all available bioprosthetic valves. [But] operators need to know the details of the surgical valve so that they can place the Melody valve appropriately.”

The key to relieving valvular obstruction is implanting the Melody valve in the narrowest point of the bioprosthetic valve, Dr. Hijazi commented. Reassuringly, he said, the incidence of Melody valve fracture was low despite relatively little prestenting, which suggests that the bioprosthetic valve serves as a kind of stent.

Proper sizing is another important consideration, Dr. Hijazi indicated. While the Melody valve is available up to a nominal diameter of 22 mm, bioprosthetic valves range up to 29 or even 31 mm in diameter. “The Melody valve will work in larger bioprosthetic valves as long the dominant issue is stenosis,” he said. But if the main problem is regurgitation, with little stenosis, then use of the larger 26-mm or soon-to-be-available 29-mm Edwards Sapien valves (Edwards Lifesciences, Irvine, CA) would be warranted, he added.

Dr. Hijazi observed that endocarditis—although uncommon—has plagued the Melody valve. Operators should be aware of this potential complication in case patients later present with suggestive symptoms.

In a telephone interview with TCTMD, Robert J. Sommer, MD, of Columbia University Medical Center (New York, NY) agreed, noting that because cardiologists do not expect endocarditis in the right side of the heart, they do not employ prophylactic medications. Together with earlier reports, the current finding “raises the question of whether there is something about the Melody valve that predisposes it to this risk,” he added.

Overall, Dr. Sommer called the valve-in-valve option “clearly a lot better than subjecting patients to recurrent surgery” and the results very good “as long as you pick your patients properly.” He emphasized the need for careful anatomical evaluation to avoid compressing the coronary arteries and caution when positioning the Melody valve directly behind the sternum to reduce the risk of fracture.

In addition, the size of the existing bioprosthetic valves must fall within certain parameters in order to accommodate the functional range of the Melody valve, which is an internal diameter between about 16 mm and 25 mm, Dr. Sommer said.

Implications for Lifetime Management

Like the authors, Drs. Sommer and Hijazi both pointed out that the viability of the valve-in-valve strategy underlines the need for collaboration between interventional cardiologists and cardiac surgeons in planning the long-term management of young patients.

“The whole paradigm of how we treat congenital heart disease has changed in light of these recent innovations,” Dr. Sommer said. Now when children with small bioprosthetic valves or deteriorating conduits return for surgery as teenagers, the surgeon needs to be aware that the next intervention will be catheter based rather than surgical, so the conduit and valve need to be a size and in a position that will accommodate the transcatheter approach, he explained.

After that, “there is almost unlimited potential for continuing to put [transcatheter] valves inside of valves,” Dr. Sommer concluded.

Study Details

 Median patient age was 26 years (range, 3-63 years). Most (71%) had tetralogy of Fallot as the underlying diagnosis.

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