Short- and Medium-Term Surgical Outcomes of Tissue-Engineered Pulmonary Valve Replacement in Sheep.

Background: Tissue-engineered pulmonary valves (TEPVs) hold considerable potential for improving outcomes in valve replacement surgeries. We investigated the surgical outcomes of TEPVs replacement in sheep, specifically examining the effects of valve type (decellularized versus adipose-derived stem cell-seeded valve [ADSC]) and the animal's age at the surgery. The primary goals were to assess survival rates, postoperative complications, and the effects of cardiopulmonary bypass (CPB) on homeostasis.

Methods: Nineteen juvenile and adult sheep were randomly assigned to orthotopic pulmonary valve replacement using either decellularized (DECELL, n = 10) or ADSC-seeded valves (CELL, n = 9). Blood gas analysis was conducted intraoperatively and postoperatively to assess CPB-related metabolic changes. The follow-up period after surgery was 6 months. Key demographic and operative parameters were recorded, and early and late postoperative complications were monitored.

Results: No significant differences were observed in operative parameters or postoperative complications between the DECELL and CELL groups. Adult sheep exhibited longer anesthesia, CPB, and operative times due to tissue fragility but demonstrated better long-term survival than juveniles, who experienced more late-stage complications, including endocarditis. CPB exposure increased lactate and reduced hemoglobin levels, particularly in adult sheep, affecting homeostasis. The overall mortality rate was 42.1%, with deaths primarily attributed to congestive heart failure and endocarditis.

Conclusion: Valve type did not significantly affect short-term outcomes and ADSC-seeding had no significant impact on operative parameters, postoperative complications, or survival rate. However, age remained a crucial factor influencing both surgical complexity and survival, highlighting the need for age-specific strategies in tissue-engineered valve applications.