Dilative characteristics of Microvel and Vasculour-II aortic bifurcation grafts

Dilation is inherent to all knitted Dacron arterial prostheses. Insufficient clinical data regarding the usual dilative characteristics of specific grafts confound its significance and management. Alterations in size of all parts of knitted aortic bifurcation grafts (43 Microvel and 37 Vasculour-II) were evaluated by CT scanning in 80 patients; 76 scans were obtained in those with Microvel and 69 in those with Vasculour-II grafts. The mean dilation values were Microvel 54% +/- 16% SD at a mean follow-up of 21 months and Vasculour-II 48% +/- 21% SD with a mean follow-up of 73 months. Serial scans and a linear correlation study indicated that the rate of progressive dilation for both grafts was relatively low. The wide range of dilation values among patients with the same graft type, and even the same implantation time, operated upon by the same surgeon, suggests that multiple etiologic mechanisms are involved. Consequently, all patients must be evaluated individually, preferably with serial scans that evaluate all parts of the graft.