Harnessing haemodynamic forces for the suppression of anastomotic intimal hyperplasia: the rationale for precuffed grafts

Objectives: standardisation of cuff geometry by manufacturing prosthetic pr ecuffed grafts (PCG) theoretically optimises haemodynamic forces. This stud y was designed in order to determine whether these beneficial flow patterns are replicated in vivo in PCG. Patients and Methods: flow visualisation and Doppler studies performed on a natomically accurate PCG models characterised in vitro anastomotic flow pat terns. Thirty-two patients (median age 68 years) in whom autologous vein wa s unavailable, underwent bypass using PCG. Post-operative analysis included qualitative assessment of flow within the distal anastomosis using Doppler colour flow mapping. Cardiac gating techniques and assessment of velocity distribution were performed to gain additional information. These in vivo r esults were validated against the bench studies. Results: a cohesive vortex was identified within the distal anastomosis of in vitro models and had an integral relationship with the cardiac cycle. Th is flow structure was also characterised using Doppler colour flow mapping in both longitudinal and transverse planes, confirming the location of the vortex within the body and proximal part of the anastomosis. Twenty-two pat ients (69%) undergoing bypass with a PCG underwent successful Doppler asses sment one week postoperatively, of whom 17 (77%) had a vortical flow struct ure identified at the distal anastomosis, similar to that characterised in vitro. Cardiac gating verified the same integral relationship of the vortex with the cardiac cycle as that described in vitro. Conclusion: the geometric configuration of precuffed grafts induced vortice s within the distal anastomoses in 17 out of 22 patients undergoing arteria l reconstruction, thereby harnessing the haemodynamic forces that may suppr ess anastomotic hyperplasia and improve patency rates.