Harnessing haemodynamic forces for the suppression of anastomotic intimal hyperplasia: the rationale for precuffed grafts.
OBJECTIVE
Standardisation of cuff geometry by manufacturing prosthetic precuffed grafts (PCG) theoretically optimises haemodynamic forces. This study was designed in order to determine whether these beneficial flow patterns are replicated in vivo in PCG.


METHODS
Flow visualisation and Doppler studies performed on anatomically accurate PCG models characterised in vitro anastomotic flow patterns. Thirty-two patients (median age 68 years) in whom autologous vein was 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 results 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. This 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 patients (69%) undergoing bypass with a PCG underwent successful Doppler assessment one week post-operatively, of whom 17 (77%) had a vortical flow structure 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.


CONCLUSIONS
The geometric configuration of precuffed grafts induced vortices within the distal anastomoses in 17 out of 22 patients undergoing arterial reconstruction, thereby harnessing the haemodynamic forces that may suppress anastomotic hyperplasia and improve patency rates.
Fisher
R K
RK
Department of Clinical Engineering, The Royal Liverpool University Hospital, UK.
How
T V
TV
Toonder
I M
IM
Hoedt
M T
MT
Brennan
J A
JA
Gilling-Smith
G L
GL
Harris
P L
PL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000714:Anastomosis, Surgical / Q000379:methods; D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods; D004867:Equipment Design; D005260:Female; D006083:Graft Occlusion, Vascular / Q000473:pathology / Q000517:prevention & control*; D006439:Hemodynamics; D006801:Humans; D006965:Hyperplasia / Q000517:prevention & control; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011138:Polytetrafluoroethylene; D017539:Tunica Intima / Q000473:pathology*; D018615:Ultrasonography, Doppler, Color
D011138:Polytetrafluoroethylene