Author + information
- aDivision of Cardiovascular Medicine, University of Virginia Health System, Charlottesville, Virginia
- bDivision of Pediatric Cardiology, University of Virginia Health System, Charlottesville, Virginia
- ↵∗Address for correspondence:
Dr. D. Scott Lim, University of Virginia, Medicine, 1215 Lee Street, Hospital Expansion Room 4033, Charlottesville, Virginia 22908.
Since the introduction of transcatheter pulmonary valve replacement by Bonhoeffer et al. (1) in 2000, there has been a veritable rush in the pediatric and congenital cardiology community to switch from surgical pulmonary valved conduit replacement to the transcatheter approach, but without the benefit of a randomized clinical trial comparing transcatheter approaches with the surgical standard of care. Therefore, we are left to infer comparisons using data from case series on procedural outcomes and complications, which generally have been favorable for the transcatheter approaches (2–5).
Based on the nonrandomized data available, in the United States, 2 transcatheter pulmonary valves are approved for clinical care: the Melody valve (Medtronic, Minneapolis, Minnesota) and the Sapien XT valve (Edwards Lifesciences, Irvine, California) (6,7). Previous publications have demonstrated, albeit in the short term, relatively low rates of endocarditis of the Melody valve (3.2% at a median follow-up of 5 months) with common culprit organisms, such as Staphylococcus aureus and Streptococcus species (3). The Sapien and Sapien XT valves have not been in use for pulmonic applications long enough to previously understand the risks of endocarditis until this present publication, although applications in the aortic position have shown an even lower incidence than expected (8).
The article by Hascoet et al. (9) this issue of JACC: Cardiovascular Interventions looks specifically at the risk of infective endocarditis following transcatheter pulmonary valve implantation with either the Melody or Sapien valves, evaluating 79 patients having undergone transcatheter pulmonary valve replacement at their center between 2008 and the present. It is notable that their follow-up period is longer than previous publications, in the intermediate range (median follow-up, 1.8 years), but that with that time frame there already is an incidence of 10.1% of endocarditis using the established diagnostic criteria.
It is even more striking that although the mix of implanted valves was nearly evenly split, the endocarditis events occurred exclusively in those patients treated with the Melody valves. The cumulative incidence of endocarditis was 24% at 4 years for Melody valves versus 0% for Sapien valves. This is the highest incidence noted for Melody valves yet published, and immediately brings us to the next question, which is why that incidence is so high.
The authors looked for aggravating factors for endocarditis using a case-control analysis, yet found that other than the occurrence of noncardiac surgery, any risk factors related to implantation of the Melody instead of a Sapien valve. The authors speculated that the use of bovine jugular vein tissue in the Melody valve may be related to the increased occurrence of endocarditis, because that has also been seen following surgical usage of bovine jugular valve implantation in the pulmonic position (10). It is probable that there are some tissue factors related to bovine jugular tissue that would predispose to tissue seeing of infectious organisms from transient bacteremia.
Additionally, a potential difference between the 2 transcatheter pulmonary valves is that the stent frame of the Melody valve is less robust, and therefore requires pre-stenting with a rigid bare metal stent first, to resist the external compressive forces from the beating aorta posteriorly. Significant degrees of deformation of the bioprosthetic pulmonary valve may lead to turbulent flow, which in turn increases the risk for bacterial seeding during bacteremia. The Sapien valve stent frame is more robust, and therefore possibly more likely to be able to withstand the external compressive forces without deformation. This in turn means the Sapien valve may be more likely to retain its optimal configuration with laminar blood flow, reducing the risk of endocarditis.
However, it is important to note, that any bioprosthetic valve is subject to a lifetime risk of endocarditis. Although the present study by Hascoet et al. (9) ought to give clinicians a thoughtful pause in their selection of which pulmonary valve to implant, it still is a call for longer-term and rigorously adjudicated clinical trial data to more adequately assess the risk/benefit ratio to our patients in terms of valve choice. More than that, it also is a good reminder for the inexpensive, low-intensity, and common-sense recommendations to reduce the risk of endocarditis: regular dental hygiene, appropriate antiplatelet therapies, and reminders for vigilance for the subtle signs of endocarditis.
↵∗ Editorials published in JACC: Cardiovascular Interventions reflect the views of the authors and do not necessarily represent the views of JACC: Cardiovascular Interventions or the American College of Cardiology.
Dr. Lim is the national primary investigator of the COMPASSION-S3 Trial, sponsored by Edwards Lifesciences, and his institution, the University of Virginia, receives funding to support that trial, although there is no direct payment to him; and has received a research grant from Edwards Lifesciences and Medtronic.
- American College of Cardiology Foundation
- Bonhoeffer P.,
- Boudjemline Y.,
- Qureshi S.A.,
- et al.
- Lurz P.,
- Coats L.,
- Khambadkone S.,
- et al.
- Kenny D.,
- Hijazi Z.M.,
- Kar S.,
- et al.
- ↵US Food and Drug Administration, Products & Medical Procedures. Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf14/p140017a.pdf. Accessed January 3, 2017.
- ↵US Food and Drug Administration, Products & Medical Procedures. Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf13/p130009s037a.pdf. Accessed January 3, 2017.
- Hascoet S.,
- Mauri L.,
- Claude C.,
- et al.