Porcine Xenograft as an Alternative to Homografts in the Ross Procedure: The Colombian Solution

This article is part of CTSNet’s Guest Editor Series, “Mastering Aortic Root Surgery—Learning From Top Surgeons”. Dr. Lorena Montes invited top cardiac surgeons from around the world to contribute clinical videos on various aortic root surgery techniques. 

As described in the late 1960s, the Ross procedure entails aortic valve replacement with a pulmonary valve autograft and reconstruction of the right ventricular outflow tract with a pulmonary homograft. Among surgical approaches for aortic valve pathology, it is the sole method for demonstrating survival rates compared to those expected in the general population. Additionally, perioperative morbidity and mortality outcomes have been notably favorable in high-volume centers for this procedure. However, its utilization is less widespread due to its technical intricacy compared to conventional aortic valve replacement, as it requires intervention on two valves and the limited or nonexistent availability of pulmonary homografts in many settings. 

The Ross procedure treats the right ventricular outflow tract using cryopreserved pulmonary homografts. Despite potential structural degeneration, these homografts have shown favorable long-term outcomes, including freedom from reintervention. However, the availability of cryopreserved homografts poses limitations in many scenarios. Porcine xenografts are a feasible and more accessible alternative, but entail a higher risk of calcification and stenosis, particularly at the proximal anastomosis. The use of porcine xenografts for reconstructing the right ventricular outflow tract in the Ross procedure has been accepted as a reasonable alternative for cases where pulmonary homografts are unavailable. However, there have been cases of first-year failure due to infundibular stenosis with subsequent stabilization over time. The first-year failure rate substantially impacts the long-term reintervention rate. Theoretically, interposing a pericardial patch at the level of the pulmonary artery or in the right ventricular outflow tract anastomosis could substantially reduce this risk, however, currently, there is insufficient evidence to support this theory. 

The authors propose a technical modification of the Ross surgery by employing the Freestyle porcine root and enlarging the right ventricular outflow tract with a heterologous pericardial scarf. This approach aims to mitigate the risk of infundibular stenosis and enhance the long-term durability of the bioprosthesis. 

Surgical Technique

The procedure was performed through a median sternotomy, with cardiopulmonary bypass established using cannulation of the ascending aorta and cavo-atrial with assisted venous drainage. Myocardial protection was achieved using antegrade and retrograde cardioplegia with del Nido solution. The Ross procedure was performed with the pulmonary autograft implanted as a total root replacement. Separate 4/0 Prolene sutures were used for the annular suture, continuous 6/0 Prolene sutures for the reimplantation of the coronary ostia, and continuous 5/0 Prolene sutures for the autograft anastomosis with the native aorta. 

Xenograft size selection was based on the distal diameter of the pulmonary trunk. Once the size was determined, the distal anastomosis of the xenograft was performed prior to the autograft pulmonary anastomosis to the aorta. After completing the autograft anastomosis to the aorta, the aortic clamp was removed, and the reconstruction of the outflow tract continued with the aorta unclamped to avoid prolonging the myocardial ischemia period. 

An 8 x 14 cm bovine pericardial patch was used to enlarge the right ventricular outflow tract. The patch was initially anastomosed to the xenograft using a continuous 4/0 Prolene suture, starting at the most posterior aspect of the xenograft and matching it with the midpoint of the pericardial patch. This ensures that the suture line is completed, and equal patch length is preserved on each side of the end of the anastomosis. At this point, the authors trimmed the excess on both sides of the pericardial patch at an approximate 30-degree angle perpendicular to the porcine root suture ring.  Subsequently, the authors define the patch length at the infundibular septum level, ensuring that the suture at this level remains free from any tension. To allow an oblique edge of the patch with the anterior edge longer than the posterior, the anterior aspect of the enlargement patch was approximately twice as long as the posterior. Once the patch was trimmed, the enlargement patch was closed with double sutures—first forward, then backward—completing the pericardial scarf construction. 

The enlargement patch anastomosis was performed with continuous 4/0 Prolene suture, starting on the left side of the infundibular septum and taking great care on the first septal branch of the anterior descending artery. Once the septal margin of the anastomosis was completed, the most anterior point of the suture was defined, aiming to avoid any torsion and excessive tension. Finally, the patch anastomosis was completed to the free wall of the right ventricular outflow tract. This pericardial scarf allowed for the proximal diameter of the porcine root to expand to approximately 45 mm, which allowed for a wide anastomosis to the right ventricular infundibulum. This technique also maintained free cardiac muscle mobility, avoided wall stress and excessive tension, which are considered to induce the inflammatory phenomenon leading to infundibular stenosis in a percentage of these biological substitutes. 

Final Comment

At the time of this video publication, the follow-up for these patients shows great results at more than one year. These findings will be published in an additional article. 

References

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9. Miskovic A, Monsefi N, Doss M, Ozaslan F, Karimian A, Moritz A. Comparison between homografts and Freestyle(R) bioprosthesis for right ventricular outflow tract replacement in Ross procedures. Eur J Cardiothorac Surg. 2012;42(6):927-933. doi:10.1093/ejcts/ezs185
10. Hechadi J, Gerber BL, Coche E, et al. Stentless xenografts as an alternative to pulmonary homografts in the Ross operation†. Eur J Cardiothorac Surg. 2013;44(1):e32-e39. doi:10.1093/ejcts/ezt147
11. Tsukube T, Kawanishi Y, Murakami H, et al. Reconstruction of Right Ventricular Outflow Tract with Stentless Xenografts in Ross Procedure. Artif Organs. 2002;26(12):1055-1059. doi:10.1046/j.1525-1594.2002.07005_3.x

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