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In Vivo Evaluation of a Porous, Elastic, Biodegradable Patch for Reconstructive Cardiac ProceduresDisclaimer

https://doi.org/10.1016/j.athoracsur.2006.06.085Get rights and content

Purpose

Several synthetic materials have been used for cardiac reconstruction in patients with complex congenital heart defects. These materials are not viable, do not grow with children, and may necessitate reoperation. We report here on the cardiac implantation of a recently developed, degradable porous material designed to facilitate cellular ingrowth during the healing process.

Description

An elastomeric, biodegradable polyester urethane urea (PEUU) was processed into circular scaffolds and used to replace a surgical defect in the right ventricular outflow tract of adult rats. Control rats were implanted with expanded polytetrafluoroethylene. Histologic evaluation was performed at 4, 8, and 12 weeks postsurgery.

Evaluation

All animals survived the surgery. Both PEUU and expanded polytetrafluoroethylene were encapsulated with fibrous tissue and had complete endothelialization on the endocardial surface with no aneurysm formation or thrombus noted. With PEUU patching, fibroblast ingrowth occurred at 4 weeks, increasing with time. In contrast, expanded polytetrafluoroethylene patches exhibited no ingrowth and elicited local inflammation that moderated with time.

Conclusions

The PEUU patch demonstrated suitable mechanical properties and biocompatible characteristics in the right ventricular outflow tract replacement model, permitting cellular integration and endocardial endothelialization with minimal inflammation. Future application of this material as a cardiovascular scaffold seems promising.

Section snippets

Experimental Animals

Adult male syngeneic Lewis rats (Harlan Sprague Dawley Inc, Indianapolis, IN) weighing 300 g to 350 g were used for the RVOT replacement procedure. The research protocol followed the National Institutes of Health guidelines for animal care and was approved by the Institutional Animal Care and Use Committee of the University of Pittsburgh.

Material Synthesis and Preparation

The PEUU was synthesized from butyl diisocyanate, polycaprolactone (2,000 MW), and putrescine [3] and processed according to the methods of previous reports in

Postoperative Course and Gross Observations

No deaths occurred during the postoperative course in either group and no gross evidence of thrombosis was present in any of the animal explants. At the time of explantation, all rat hearts exhibited minimal thoracic adhesions with no recognizable pattern of adhesive tissue present in ePTFE or PEUU implanted animals. Neither group showed any dehiscence or aneurysm formation at the site of the implanted patch in the RVOT at each time point. Looking at macroscopic images of the RVOT 12 weeks

Comment

The results with the PEUU patch represent the first report on the implantation of this material as a step toward more extensive in vivo studies in the cardiovascular system. This material has theoretical advantages over nondegradable materials used in reconstructive cardiovascular procedures in that it seems capable of mechanically performing early in the implant period while allowing tissue ingrowth that takes over this mechanical role by 3 months in this model. As with other

Disclosures and Freedom of Investigation

This work was supported by the National Institutes of Health (HL #069368). The polyester urethane urea material was synthesized and processed by the authors, who also had full control of the study design, methods used, outcome measurements, data analysis, and production of the written report.

References (8)

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Disclaimer

The Society of Thoracic Surgeons, the Southern Thoracic Surgical Association, and The Annals of Thoracic Surgery neither endorse nor discourage use of the new technology described in this article.

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