Vascular 10

Abstract

Aims: Abnormal haemodynamic conditions are implicated in the development of anastomotic myointimal hyperplasia (MIH). We have investigated in vivo inter-patient variation in the geometry of distal graft anastomoses, which may strongly influence local flow conditions, MIH formation and clinical outcome. Methods: The distal anastomotic geometry was acquired in vivo by 2-D or 3-D time of flight MR angiography from 10 patients undergoing infrageniculate autologous venous bypass at a median 2 weeks postoperatively. Four patients underwent repeat examinations 13–49 days later. Computer generated 3-D lumen surface reconstructions of the anastomosis were produced and lumen centrelines were extracted. Geometric features including angles between graft and proximal host (α), graft and distal host (β), and proximal and distal host (γ) were calculated. Diameter ratios between the graft and host vessels were calculated from the cross-sectional areas of the three vessels at the reconstructed anastomosis boundaries. A preliminary distal anastomotic planarity index (API) is introduced (for planar anastomoses API = 0) and was evaluated for the patient population studied. Results: Good agreement was found between the distal anastomotic angles in the initial and follow-up examinations. The differences in the angles varied between 1 and 10 degrees with a mean of 4.3 degrees. Conclusions: In the early postoperative period distal graft anastomoses exhibit wide variations in angles α, β, and γ, diameter ratios, and planarity. The reported relationship between local haemodynamics and MIH suggests that these geometric features may play a role in MIH development.