REENDOTHELIALIZATION AND PLATELET-DERIVED GROWTH-FACTOR ACTIVITY ASSOCIATED WITH INTRAARTERIAL STENTED GRAFTS

The purpose of this study was to determine whether intraluminal placem ent affects reendothelialization rate and platelet-derived growth fact or (PDGF) secretion in polytetrafluoroethylene (PTFE) grafts. Thirty d ogs underwent infrarenal abdominal aorta PTFE interposition (12) or in traluminal stented (18) grafting. Grafts were explanted at four and ei ght weeks and rates of endothelial ingrowth calculated. Cell-specific immunohistochemical stains were used to quantitate perianastomotic end othelial (CD 31+), proliferating (PCNA+), and PDGF-secreting cell cont ent. Mean endothelial cell resurfacing rates were 1.1 +/-0.2, 3.9 +/-0 .2, 1.4 +/-0.2, and 2.4 +/-0.2 mm/week for the four-week control (6), stented (7), eight-week control (6), and eight-week stented (8) grafts at the proximal anastomosis, and 1.2 +/-0.2, 3.8 +/-0.2, 1.2 +/-0.2, and 2.6 +/-0.2 mm/week, respectively, at the distal anastomosis. Reend othelialization was greatest with intra-arterial stented grafts at bot h four and eight weeks (P<0.01). Between four and eight weeks, the dec line in resurfacing rates among stented grafts was attributed to the c omplete reendothelialization observed in eight-week specimens. PDGF+ c ell content was similar among four-week control and stented grafts, an d greatest in eight-week controls (P<0.05). An inverse correlation was noted between PDGF+ and endothelial (CD 31+) cell content at both ana stomotic sites (r=-0.34, P<0.01). Trends between increasing reendothel ialization rates with decreasing PDGF+ cell content did not achieve st atistical significance (P=0.08). Intra-arterial graft placement accele rates reendothelialization of PTFE grafts. PDGF secretion decreases wi th progressive endothelial cell coverage.