Abstract
The purpose of this study was to determine whether intraluminal placement affects reen dothelialization rate and platelet-derived growth factor (PDGF) secretion in polytetra fluoroethylene (PTFE) grafts.
Thirty dogs underwent infrarenal abdominal aorta PTFE interposition (12) or intra luminal stented (18) grafting. Grafts were explanted at four and eight weeks and rates of endothelial ingrowth calculated. Cell-specific immunohistochemical stains were used to quantitate perianastomotic endothelial (CD 31 +), proliferating (PCNA+), and PDGF secreting cell content.
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. Reendothel ialization was greatest with intra-arterial stented grafts at both four and eight weeks (P<0.01). Between four and eight weeks, the decline in resurfacing rates among stented grafts was attributed to the complete reendothelialization observed in eight-week specimens. PDGF+ cell content was similar among four-week control and stented grafts, and greatest in eight-week controls (P<0.05). An inverse correlation was noted between PDGF+ and endothelial (CD 31 +) cell content at both anastomotic sites (r=-0.34, P<0.01). Trends between increasing reendothelialization rates with decreasing PDGF+ cell content did not achieve statistical significance (P=0.08).
Intra-arterial graft placement accelerates reendothelialization of PTFE grafts. PDGF secretion decreases with progressive endothelial cell coverage.
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