THE ROLE OF PLATELET-DERIVED GROWTH-FACTOR IN INTRALUMINAL STENTED GRAFT HEALING

BACKGROUND: Intraluminally placed polytetrafluoroethylene grafts are a ssociated with enhanced graft endothelialization and diminished intima l hyperplasia when compared with interposition grafts. This study dete rmined the role of platelet-derived growth factor in intraluminal graf t healing. STUDY DESIGN: Thirty dogs underwent infrarenal abdominal ao rta polytetrafluoroethylene interposition (control, n=15) or intralumi nal stented (n=15) grafting. Grafts were explanted at 1, 3, and 6 week s. The percent of graft area endothelialization and intima to media he ight ratios were calculated. By using protein electrophoresis and the Western blot technique, platelet-derived growth factor, identified by immunolabeling with anti-platelet-derived growth factor antibody, was isolated from proximal, mid-, and distal graft regions and was quantif ied using densitometry. RESULTS: Graft area endothelialization was 0+/ -3.3 percent, 2.3+/-3.3 percent, and 19.0+/-3.3 percent for 1-, 3-, an d 6-week controls; and 4.7+/-3.7 percent, 30.5+/-3.3 percent, and 86.8 +/-3.3 percent for 1-, 3-, and 6-week stented grafts. Endothelializati on was greater in stented grafts at 3 and 6 weeks (p<.01). Proximal an astomosis intima to media height ratios were 1.61+/-0.15, 1.54+/-0.14, and 1.48+/-0.15 for 1-, 3-, and 6-week control grafts, and 0.42+/-0.1 8, 0.41+/-0.15, and 0.47+/-0.14 for 1-, 3-, and 6-week stented grafts. Similar intima to media height ratio values present at the distal ana stomosis. Lower intima to media height ratios were observed in all ste nted grafts (p<.01). The platelet-derived growth factor content at 1-, 3-, and 6-weeks was lower in all stented grafts when compared with co ntrols. The content of platelet-derived growth factor was greatest in 3-week controls, with a significant difference noted in the mid-graft region (p<.05). The content of platelet-derived growth factor remained stable in all stented graft regions over 6 weeks. An inverse correlat ion between stented graft platelet-derived growth factor content and e ndothelialization (r=-0.43) and a positive correlation with proximal a nastomotic intimal hyperplasia (r=0.73) were identified. CONCLUSIONS: Lower platelet-derived growth factor content is associated with decrea sed intimal hyperplasia and improved healing in intra-arterial polytet rafluoroethylene grafts.