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 postoperative 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 bifurcation grafting were randomized to receive a collagen-sealed warp-knitted polyester graft (n = 16 patients) or a gelatin-sealed Köper-knitted polyester graft (n = 18 patients). Alterations in size of all parts of the grafts were evaluated by helical computed tomographic scanning at postoperative day 8, at 3 months, and at 6 months. Results: On postoperative day 8, the mean dilation of the Köper-knitted grafts 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% for the stem and 33% ± 18% for the limbs. No increase in graft dilation was observed at 3 and 6 months. Despite the wide range of values among patients with the same graft type, at each time interval, the Köper-knitted grafts dilated 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-month follow-up interval, the Köper-knitted polyester structure dilated less than the warp-knitted structure. Longer-term serial scans should allow a better understanding of the clinical significance of graft dilation. (J Vasc Surg 2000;31:157-63.)