Experimental Study of Materials for Patch Graft on Right Ventricular Outflow Tract under Extracorporeal Circulation in Dogs. Comparison between Denacol EX-313-Treated Bovine Jugular Vein Graft and Expanded Polytetrafluoroethylene(EPTFE) Graft.

Abstract

ABSTRACT. A comparison between a bovine jugular vein treated with a hydrophilic polyepoxy compound cross-linker (Denacol), and expanded polytetrafluoroethylene (EPTFE), an artificial material, as a patch graft for the reconstruction of the right ventricular outflow tract under extracorporeal circulation in dogs, as if they had pulmonic stenosis, was made. Hemodynamic and histological examinations were conducted two weeks after the transplantation. Hemodynamic problems were not observed in either the Denacol or EPTFE groups. Macroscopically, organization of new tissue on the graft surface was more marked in the EPTFE group than in the Denacol group, and newly-formed tissue was seen surrounding the border of the graft and burying it in the EPTFE group. In the Denacol group, microscopic findings revealed the presence of inflammatory cells and fibroblasts, and an invasion of the graft by collagen fibers and elastic fibers. In the EPTFE group, there was minimal cellular infiltration of the graft and a thick layer consisting of collagen fibers and fibroblasts was observed around the graft. These results indicated that two weeks after transplantation the graft was better assimilated and organized with blood vasculature in the patch graft in the Denacol group than in the EPTFE group. KEY WORDS: canine, Denacol EX-313, EPTFE, patch graft, pulmonic stenosis.The occurrence of right ventricular outflow tract stenosis, one of the congenital cardiovascular abnormalities seen in dogs, is generally accompanied by various disorders such as pulmonic stenosis and tetralogy of Fallot. Correction of the condition commonly involves reconstruction of the narrow segment using various materials [3,13,14,18,19,22]. However, only limited studies have been conducted regarding the use of these materials for transplantation [7,9].The present study investigated the hemodynamic and histological effects of using the hydrophilic polyepoxy compound cross-linker (Denacol)-treated graft and the expanded polytetrafluoroethylene (EPTFE) graft as transplantation materials for the reconstruction of right ventricular outflow tract stenosis with pulmonic stenosis under extracorporeal circulation in dogs. The evaluations were conducted two weeks postoperatively. MATERIALS AND METHODS Animals:Ten clinically healthy beagle dogs were examined physiologically and randomly distributed into two groups: An EPTFE group, (average weight 10.86 ± 0.55 kg, n=5) and a Denacol group, (average weight 10.69 ± 0.53 kg, n=5) with two males and three females in each group. The dogs were vaccinated with a mixed vaccine and were negative for microfilaria and Brucella organisms. General hematological examination, blood chemical examination, plain thoracic radiography, electrocardiography, and phonocardiography revealed no abnormal findings. Preparation of the Denacol graft:The jugular veins of apparently healthy cattle were collected from a slaughter house. After trimming, they were placed in 1% protamine solution and cross-linked with 4% Denacol (Denacol R EX-313, Nagase Chem...

Right Ventricle to Pulmonary Artery Reconstruction Using a Valved Homograft

“…Among the patients who received an implant made of ePTFE, none developed severe stenosis, but mild to moderate stenosis of 24-50 mmHg-was observed in some cases. Although several comparative studies on the use of ePTFE have emphasized its advantages, 28 animal experiments have reported disadvantages of ePTFE for use in the RVOT (eg, thickening of the ePTFE consisting of collagen fibers and fibroblasts 29 and focal calcification 30 ). Iemura et al emphasized the advantages of ePTFE for RVOT reconstruction; on the other hand, they also reported a case of deterioration of ePTFE applied on the RVOT, which resulted in RV failure and ultimately death.…”

A Long Term Comparison between Denacol EX-313-Treated Bovine Jugular Vein Graft and Ultrafine Polyester Fiber Graft for Reconstruction of Right Ventricular Outflow Tract in Dogs.

“…Preparation of the Denacol graft: The methods used to prepare the Denacol graft were previously described in detail [4,6].…”

“…Polyepoxy compounds (Denacol ® EX-313) is less toxic than the cross-linker glutaraldehyde that has been used in the past, and because it is hydrophilic, it is characterized by strong affinity for cells and has been used for treating natural graft material, such as bovine vein [4,7,14]. We transplanted Denacol ® EX-313-treated bovine vein patch grafts into the pulmonary arteries of dogs, and observations over a short period of time revealed that they possessed properties superior to those of artificial material [6]. In the present experiment we observed hemodynamics and tissue findings over a period of one year after graft transplantation and made comparisons with artificial material.…”

Comparison of Extracapillary and Endocapillary Blood Flow Oxygenators for Open Heart Surgery in Dogs: Efficiency of Gas Exchange and Platelet Conservation.

“…The myocardium was protected by antegrade injection of cold cardioplegia solution, and the surface of the heart was cooled regionally using ice slush. Dilation and remodeling of the right ventricular outflow tract in all dogs was performed using a patch graft technique to simulate pulmonary stenosis [10,17]. After completing the necessary procedures, switching back to partial extracorporeal circulation, the heart was massaged manually, and cardiac activity was reinitiated using a defibrillator.…”