Effect of stent-graft compliance on endotension after EVAR.
OBJECTIVE
To investigate whether, and to which extent, the type of graft has influence on the pressure in the aneurysm sac.


METHODS
The study consisted of a dynamic and a static experiment. In the dynamic experiment, a latex aneurysm was inserted into an in-vitro circulation model, with variable (80-180 mmHg) systemic systolic pressure and a pulse pressure of 40 mmHg. Seven types of devices were used to exclude the aneurysm: a latex reference graft, 3 stentless grafts made of different fabrics, and 3 different types of commercially produced stented grafts used for endovascular aneurysm repair (EVAR). The systolic and diastolic intra-aneurysm pressures (IAP) were measured, along with the pulse pressure. The mean IAP and pulse pressures were compared for each category of graft (stented/stentless) and for each graft. In the static experiments, the compliance of each graft and the latex aneurysm were determined by measuring the change in volume necessary to obtain a change in pressure. Furthermore, the IAP with each graft was measured in a nonpulsatile situation under systolic pressures varying between 60 and 140 mmHg.


RESULTS
The experiments showed that, with increasing systemic pressures, there was a small pressure (<5 mmHg) increase in the aneurysm, but there was no significant difference among grafts in the dynamic or the static experiments (p = 0.12 and p = 0.17, respectively). With the 3 stented EVAR grafts, there was less pressure transmission than with the 3 stentless grafts, but this difference was not significant (p>0.05).


CONCLUSIONS
This in-vitro study demonstrated that there is a clinically irrelevant pressure transmission through the graft wall and no significant difference in the pressure transmission between stented and stentless grafts.
Bosman
Willem-Maarten P F
WM
Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands. W.M.P.F.Bosman@lumc.nl
Hinnen
Jan-Willem
JW
Rixen
Daniel J
DJ
Hamming
Jaap F
JF
D000783:Aneurysm / Q000503:physiopathology / Q000601:surgery*; D001794:Blood Pressure; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D003187:Compliance; D019544:Equipment Failure Analysis; D007840:Latex / Q000737:chemistry; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011673:Pulsatile Flow; D015607:Stents; D013314:Stress, Mechanical
D007840:Latex