Can knitting structure affect dilation of polyester bifurcated prostheses?A randomized study with the use of helical computed tomography scanning

Purpose: The aim of this study was to prospectively evaluate the postoperat ive dilation of two types of knitted polyester arterial prostheses with the use, of helical computed tomographic scanning. Methods: Thirty-four patients who underwent aortoiliac or aortofemoral bifu rcation grafting were randomized to receive a collagen-sealed warp-knitted polyester graft (n = 16 patients) or a gelatin-sealed Koper-knitted polyest er graft (n = 18 patients). Alterations in size of all parts of the grafts were evaluated by helical computed tomographic scanning at postoperative da y 8, at 3 months, and at 6 months. Results: On postoperative day 8, the mean dilation of the Koper-knitted gra fts was 18% +/- 8% for the stem and 15% +/- 12% for the limbs. At the same time period, the mean dilation of warp-knitted grafts was 27% +/- 13% far t he stem and 33% +/- 18% for the limbs. No increase in graft dilation was ob served at 3 and 6 months. Despite the wide range of values among patients w ith the same graft type, at each time interval, the Koper-knitted grafts di lated significantly less than the warp-knitted grafts (P < .05). Conclusion: In this randomized study, helical computed tomographic scanning was an accurate technique with which to assess graft dilation. For a 6-mon th follow-up interval, the Koper-knitted polyester structure dilated less t han the warp-knitted structure. Longer-term serial scans should allow a bet ter understanding of the clinical significance of graft dilation.