Long Term Efficacy and Fate of a Right Ventricular Outflow Tract Replacement Using a Novel Developed Material with Optimized Biodegradation and Elasticity

For decades, researchers have investigated the ideal material for clinical use in the cardiovascular field. Several substitute materials are used clinically, but each has drawbacks. Recently we developed poly(e-caprolactone-co-D,L-lactide) (P(CL-DLLA)) polymers with optimized biodegradation and elasticity by adjusting the CL/DLLA composition, and used these polymers in right ventricular outflow tract (RVOT) replacement to evaluate long-term efficacy and outcomes. This P(CL-DLLA) material was processed into a circular patch and used to replace a surgical defect in the RVOT of adult rats. Control rats were implanted with expanded polytetrafluoroethylene (ePTFE). Histologic evaluation was performed at 8, 24, and 48 weeks post-surgery. All animals survived the surgery with no aneurysm formation or thrombus. In all periods, ePTFE demonstrated fibrous tissue. In contrast, at 8 weeks P(CL-DLLA) showed infiltration of macrophages and fibroblast-like cells into the remaining material. At 24 weeks, P(CL-DLLA) was absorbed completely, and muscle-like tissue was present with positive staining for α-sarcomeric actinin and cTnT. At 48 weeks, the cTnT-positive area had increased. The P(CL-DLLA) with optimized elasticity and biodegradation induced cardiac regeneration throughout the 48-week study period. Future application of this material as a cardiovascular scaffold seems promising.