Sapien a ‘Viable and Durable’ Option in Transcatheter Pulmonary Valve Replacement

Off-label use of the Sapien and Sapien XT valves represents a “viable and durable option” for restoring pulmonary valve function in patients with right-ventricular outflow tract (RVOT) disorders, according to the results from a single Canadian center.

In 25 patients who received the percutaneously implanted valve, including 4 given the newest Sapien XT device, the technical success rate was 96%, with 1 patient requiring elective surgical pulmonary valve replacement for a high residual gradient. After a median follow-up of 3.5 years, there were no reported deaths, episodes of endocarditis, or stent fractures.

In the December 21, 2015, issue of JACC: Cardiovascular Interventions, William Wilson, MBBS, of University Health Network (Toronto, ON), and colleagues say that the use of the Sapien system (Edwards Lifesciences), which was developed and approved for aortic-valve replacement, allows physicians to treat RVOTs with larger diameters than they are able to do with the currently approved Melody transcatheter pulmonary valve system (Medtronic).

The largest Sapien valve has a diameter of 29 mm—the maximum diameter is 24-mm with the Melody valve—and this “affords treatment of patients with larger homografts, biological valves, and selected native outflow tracts,” report investigators.

Among the patients treated, the implantation site included a biological valve in 16 patients and a homograft conduit in 9. Upon implantation of the valve—pre-stenting was performed in all patients, including the use of a covered stent in 52% of cases—there were significant reductions in the mean RV-to-systemic pressure ratio (from 0.64 to 0.36) and RV-pulmonary artery outflow gradient (39 to 9; P < .001 for both), and there was no significant pulmonary regurgitation.

During follow-up, there was 1 reintervention in a 24-year-old patient who received the Sapien valve after he returned at 1 year with recurrent symptoms and severe valvular regurgitation. The exact reason for the valve failure was unknown, the researchers report.

Lacking Options in Congenital Heart Interventions

In an editorial, Dennis Kim, MD, Children’s Healthcare (Atlanta, GA), writes that the off-label use of medical technology in pediatric and adult congenital interventional cardiology is not unusual. “When one considers the typical inventory present in congenital interventional catheterization laboratories, it is sobering to realize how little has been developed for specific application in congenital cardiac interventions,” states Kim.

The Melody system, Kim says, is largely unchanged from when it was first designed. In contrast, US physicians have access to 5 transcatheter aortic-valve systems, 2 more are available in Canada and Europe, and others are in development. Although the Sapien and Sapien XT were implanted successfully, the systems are designed for aortic-valve replacement where the catheter course is more straightforward than in the right heart, adds Kim. 

Despite the off-label use, the high procedural success rate in the single-center series “speaks to the relative reliability of the transcatheter technique for percutaneous pulmonary valve replacement and to the reproducibility of successful valve implantation in the hands of experienced operators,” according to Kim.

The data suggest the Sapien and Sapien XT valves continued to perform well over the 3.5-year follow-up period, just like the Melody valve does. Kim notes that endocarditis after transcatheter pulmonary-valve implantation is a “vexing” problem, particularly with Melody, and while it was not identified in the present series, the numbers are too small to make comparisons between the Sapien and Melody valve systems.

During follow-up, there were no reported cases of stent fracture, but these events were not systematically searched for, according to the researchers. They point out there are no reports to date of fractures with the Sapien valve in the aortic or pulmonic position but add that a more systematic follow-up protocol will be needed to keep tabs on functional status and valve function in the pulmonic position.

Sources: 
1. Wilson WM, Benson LN, Osten MD, et al. Transcatheter pulmonary valve replacement with the Edwards Sapien system. J Am Coll Cardiol Intv. 2015;8:1819-1827.
2. Kim DW. Off-label, on-target [editorial]. J Am Coll Cardiol Intv. 2015;8:1828-1830.

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