Marathe SP, Bell D, Betts K, Sayed S, Dunne B, Ward C, Whight C, Jalali H, Venugopal P, Andrews D, Alphonso N.
Eur J Cardiothorac Surg. 2019 Feb 7. doi: 10.1093/ejcts/ezz021. [Epub ahead of print]
Select Item 30729809
- In this retrospective study of right ventricular outflow tract reconstruction, Freestyle valves and pulmonary homograft exhibited similar freedom from reintervention and structural valve degeneration up to 10 years after placement. Beyond 10 years, the pulmonary homografts exhibited better performance in these categories.
- However, it is difficult to compare results from this and other small studies that utilize a limited number of available conduits with varying techniques.
Commentary from Dr. Jeremy Herrmann (Indianapolis), section editor of Congenital Heart Surgery Journal Watch: The discussion about which conduit for right ventricular outflow tract reconstruction remains undecided. Evidence continues to slowly grow, but long-term data for the Freestyle porcine aortic valve use for pulmonary valve position are limited. In this study, the group from University of Queensland in Brisbane, Australia, provides a comparison of longer term outcomes of patients <20 years who underwent pulmonary valve replacement (PVR) with either a pulmonary homograft or Freestyle valve.
The authors primarily analyzed freedom from reintervention (surgical and/or catheter-based) and structural valve degeneration (peak gradient greater than 50 mm Hg and/or more that moderate pulmonary regurgitation). A total of 215 patients were included, 163 in the homograft group and 52 in the Freestyle group. The median follow-up was similar for both groups at approximately 8 years. Tetralogy of Fallot was the most common underlying diagnosis in both categories.
Compared to the Freestyle group, patients in the homograft group were younger (14.1 versus 10.2 years) and received conduits with a lower z-score (0.4 versus 1.5). Freedom from reintervention at 5, 10, and 15 years for the homograft group was 96%, 88%, and 81% and for the Freestyle group, 98%, 89%, and 31%. Freedom from structural valve degeneration at 5, 10, and 15 years for the homograft group was 92%, 87%, and 77% and for the Freestyle group, 96%, 80%, and 14%.
The two conduits exhibited overall similar performance up to 10 years after placement then appeared to diverge with more structural valve degeneration and reinterventions in the Freestyle group. A similar pattern was seen when propensity matching was used for 27 pairs of patients. The authors also observed that homografts fared better in an orthotopic position versus heterotopic position and that oversizing Freestyle valves did not affect later performance.
This retrospective, single-center study with mid-term follow-up offers additional insight into how well different conduits perform over time. There are several unanswered questions that could help to understand other implications of these findings:
- How did the conduits fail (e.g., due to distal anastomotic stenosis)?
- How were conduits selected, and was there any change in conduit preference over time?
- When the conduits did fail, were patients more likely to be able to undergo transcatheter PVR with either conduit type?
As with most other studies of this topic, the present study is not comprehensive. Importantly, no bovine jugular venous conduits were used. At our center, we prefer to use bovine jugular venous conduits in patients less than 18 years of age and Freestyle valves in adult patients undergoing PVR. We agree with the authors in that stentless valves generally outperform stented valves in the pulmonary position. Additionally, when it is necessary to use a pulmonary homograft, we prefer those that have been decellularized. In our experience, these have demonstrated improved durability possibly due to a reduced recipient immune response.
This study further demonstrates the considerable inter-institutional practice variation with conduit selection. The debate of the optimal conduit for right ventricular outflow tract remains undecided. Given the nuances of conduit characteristics and implant techniques, it may be difficult to absolutely compare results between institutions. Combining the experience of multiple centers may be necessary to capture a broader estimation of the long-term performance of the available conduits for right ventricular outflow tract reconstruction, however.