Pressure loading of the aneurysm sac under endoleak type III-simulation

Transabdominal aortic aneurysm repair has been shown to reliably prevent fatal aneurysm rupture but is highly traumatic, especially for older patients. On the other hand, the more modern endovascular approach is less invasive, but questions of long term pressure reduction within the aneurysm sac, and possible consequent rupture, remain open. The aim of this in vitro study was to estimate the significance of pressure loading of the aneurysm sac under endoleak type III-simulation. A silicone aneurysm was integrated into a pulsatile in vitro circulation model. Systemic (SP) and aneurysm sac pressure (ASP) were measured under the following conditions: (1) with a Talent®-bifurcation in situ without clotting simulation, (2) with clotting simulation, (3) with a non compliant 'stiff-stent', (4) with a Talent®-stent and concomitant type III-endoleak with no outflow, (5) with free outflow through an inferior mesenteric artery (IMA); and (6) with a 100 mmHg back pressure within the IMA. All aneurysm sac pulse pressures (difference between systolic and diastolic pressure) were smaller than systemic pulse pressures. Mean ASP and SP were similar for the cases in which clotting was not simulated (111 mmHg vs 111 mmHg) and when endoleak occurred into a sealed sac (89 mmHg vs 102 mmHg). With sufficient aneurysm exclusion, a mean ASP reduction to 28.5% of the SP occurred. A further decrease was possible by implantating a custom made 'stiff-stent' (2 mmHg). The same result was achieved with endoleak but open outflow via a patent IMA. However, in the case of 100 mmHg back pressure via the IMA, a substantial ASP increase resulted (95.5 mmHg). Even with sufficient aneurysm exclusion, complete pressure elimination could not be achieved. Type III-endoleak can lead to systemic ASP in vitro. A method to continuously keep ASP under surveillance should be the aim of further investigations. Until then close follow-up is essential.

Subjects

Abdominal aortic aneurysm

Endoleak typ-III

Endovascular aneurysm repair

Pressure measurement

Stent prosthesis

Transabdominal implantation

DDC Class

610: Medicine, Health

620: Engineering

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Pressure loading of the aneurysm sac under endoleak type III-simulation