Pulmonary valve replacement (PVR) is the most frequent surgery in adults with congenital heart disease. The most common indication is pulmonary regurgitation after right ventricular outflow tract reconstruction. A competent pulmonary valve alleviates symptoms and preserves cardiac function.
There is significant controversy regarding the best bioprosthesis for the pulmonary position. The most common biological grafts are porcine and bovine valves. Evidence suggests that bovine bioprostheses are more durable in the aortic position; however, this difference has not yet been demonstrated in the pulmonary position.
In today’s study, Said SM et al. report their experience with the Inspiris Resilia bioprosthesis (Edwards). They reviewed all PVR cases with the Inspiris Resilia bioprosthesis from August 2019 to October 2021. During this period, they operated on 27 patients (56% female) with a mean age of 22 ± 15 years. The majority had tetralogy of Fallot (48%) as their primary diagnosis. Five patients had been previously treated via catheterization. The indexed right ventricular end-diastolic volume was 164 mL/m², and the mean prosthesis size was 25 mm. Most patients (78%) had undergone at least one prior sternotomy.
In 22 patients, the procedure was performed using the standard technique, consisting of a longitudinal incision over the pulmonary artery or a patch in the right ventricular outflow tract. The remnants of the native pulmonary valve and muscular bands causing right ventricular outflow tract obstruction were removed. The bioprosthesis was implanted using a running suture, and a roof over the right ventricle and pulmonary artery was created with a patch of either pericardium or Contegra. In the remaining five patients, the prosthesis was implanted within a conduit.
As a result, six patients presented with trivial or mild pulmonary regurgitation at discharge. No in-hospital mortality was reported. After a mean follow-up of 16 months, there were no deaths or surgical reinterventions. However, half of the patients operated with the standard technique (13 patients) developed prosthetic regurgitation, which was moderate in six cases and severe in three. These three patients required a transcatheter valve-in-valve procedure. Interestingly, none of the five conduit-supported cases showed regurgitation during follow-up.
The authors expressed concern regarding the use of the Inspiris Resilia bioprosthesis in the pulmonary position. They proposed several theories about this early regurgitation: distortion of the prosthesis due to patch roofing techniques, changes in right ventricular geometry from reverse remodeling, or inadequate coaptation of the prosthetic leaflets in a low-pressure chamber.
COMMENTARY:
The Inspiris Resilia prosthesis is a next-generation biological prosthesis made from bovine pericardium modified through stable blocking and glycerolization. This process permanently blocks free aldehyde groups in the tissue, preventing calcification and structural degeneration. It also eliminates the need for glutaraldehyde preservation, allowing dry storage without requiring rinsing before use. Furthermore, it is mounted on an expandable stent, enabling transcatheter valve-in-valve treatment in the case of structural degeneration. Various publications support its good short-term performance, with only two cases of early degeneration reported at 12 and 24 months, respectively.
PVR with a bioprosthesis is an off-label indication. Few studies report long-term outcomes. When interpreting these results, the diverse patient ages, procedural eras, and prosthesis sizes must be considered. Additionally, immunological factors and surgical complexity further complicate comparisons.
Hemodynamics differ between the heart’s two sides in terms of pressure and rheology. Data from the aortic position should not be extrapolated to the pulmonary position. All bioprostheses are designed for the left heart. In vitro studies show varying behavior depending on the pressures they encounter. In low-pressure settings, such as the pulmonary position, prostheses exhibit slower leaflet coaptation, reduced insufficiency duration and volume, lower pressure gradients, and a decreased effective orifice area.
Broadly, the reported freedom from reintervention at five years is 95% (range 50–98%), and at 10 years, 81% (range 66–85%). At La Paz and Ramón y Cajal Hospitals, we compared porcine and bovine bioprostheses using propensity score analysis. The freedom from prosthetic degeneration at 3, 5, and 10 years was 97%, 93%, and 89% for porcine valves and 100%, 98%, and 79% for bovine valves. We found no differences between the two within the first five years; however, bovine prostheses showed greater structural degeneration afterward (HR = 6.99, p = .03).
The Minnesota group’s study has multiple limitations: its retrospective nature, the small patient number (n = 27), and the absence of more precise complementary tests, such as 4-dimensional CT scans, to detect leaflet thrombosis. These shortcomings require cautious interpretation of the results and prevent drawing premature conclusions. Nonetheless, it is worth emphasizing that despite the limited number of patients, this represents the largest reported experience with the Inspiris Resilia bioprosthesis in the pulmonary position in the literature.
In conclusion, articles like the one analyzed today compel us to adopt a scientific mindset. With results challenging the status quo, they urge us to scrutinize innovations critically. In this case, the new Inspiris Resilia bioprosthesis (Edwards) does not offer reliable outcomes in the pulmonary position. As St. Augustine once said, “The appetite for novelty leads man to extreme anguish.”
REFERENCE:
Said SM, Hiremath G, Aggarwal V, Bass J, Sainathan S, et al. Concerning Outcomes for the Edwards Inspiris Resilia Bioprosthesis in the Pulmonary Position. Ann Thorac Surg. 2023 Apr;115(4):1000-1007. doi: 10.1016/j.athoracsur.2022.09.026.
