Significance of endotension, endoleak, and aneurysm pulsatility after endovascular repair.
OBJECTIVE
The lack of aneurysm pulsatility after endovascular aneurysm repair (EVAR) is deemed by some an important guide to the effectiveness of exclusion. However, factors that contribute to aneurysm pulsatility after EVAR have not been elucidated. This study quantitatively analyzed the effects of systemic pressure, aneurysm sac pressure, endoleak, branch outflow from aneurysm sac, and intra-sac thrombus on aneurysm pulsatility after EVAR.


METHODS
In an ex vivo model, an artificial aneurysm sac was incorporated within a mock circulation comprised of rubber tubing and a pulsatile pump. The aneurysm sac was then completely excluded from the circulatory circuit with two types of stent-grafts, ie, supported and unsupported, and heparinized canine blood was circulated. Systemic circulation and aneurysm sac pressure was recorded in the absence and presence of endoleaks, and simulated open and closed lumbar branch outflow from the aneurysm sac. The aneurysm sac was then filled with organized human thrombus, and all pressure measurements were repeated. Two observers blinded to the above-mentioned variables independently evaluated aneurysm sac pulsatility with palpation in five separate experiments. Analysis of variance was performed, with significance accepted at P =.05.


RESULTS
Systemic pressure was simulated in the artificial circulation to range from 100/60 to 180/60 mm Hg. Regardless of the simulated lumbar branch outflow from the aneurysm, sac pressure was directly related to the presence of endoleak (P <.001). Aneurysm sac pulsatility was present only when the lumbar branch outflow was patent and not dependent on sac pressures. Aneurysm sac thrombosis or type of stent-graft did not influence sac pressure and pulsatility.


CONCLUSIONS
In this model, after EVAR pulsatility depends on aneurysm sac outflow, regardless of endoleak, sac thrombosis, sac pressure, or stent-graft. Furthermore, persistent pulsatility does not predict systemic intra-sac pressure, nor does lack of pulsatility reflect freedom of the aneurysm sac from systemic pressurization. This ex vivo model suggests that aneurysm pulsatility is an unreliable guide for predicting aneurysm sac pressurization after EVAR. Other diagnostic methods must be used to assess successful aneurysm exclusion.
Mehta
Manish
M
Division of Vascular Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, New York, NY, USA. MehtaM@mail.amc.edu
Veith
Frank J
FJ
Ohki
Takao
T
Lipsitz
Evan C
EC
Cayne
Neal S
NS
Darling
R Clement
RC
D000714:Anastomosis, Surgical / Q000009:adverse effects; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D001696:Biomechanical Phenomena; D001775:Blood Circulation / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000379:methods; D006801:Humans; D008955:Models, Cardiovascular; D011673:Pulsatile Flow / Q000502:physiology*; D015607:Stents; D013927:Thrombosis / Q000503:physiopathology