In-vitro particle image velocimetry assessment of the endovascular haemodynamic features distal of stent-grafts that are associated with development of limb occlusion. Issue 2 (3rd April 2021)

• Record Type: Journal Article
• Authors: Yazdi, Sina G.; Docherty, Paul D.; Khanafer, Adib; Jermy, Mark; Kabaliuk, Natalia; Geoghegan, Patrick H.; Williamson, Petra
• Is Part Of: Journal of the Royal Society of New Zealand. Volume 51:Issue 2(2021)
• Page Start: 361
• Page End: 374
• Publication Date: 2021-04-03
• Subjects: Particle image velocimetry -- silicone phantom -- haemodynamics -- compliance -- grafts -- limb occlusion -- recirculation; Science -- Periodicals; 505
• DOI: 10.1080/03036758.2020.1826988
• Languages: English
• ISSNs: 0303-6758

Abstract

ABSTRACT: Aneurysms are common vascular diseases which affect normal haemodynamics in the aorta. Endovascular aortic repair (EVAR) using stent-grafts is a common treatment that excludes the aneurysm from the circulation, preventing further growth and eventual rupture. However, complications such as endoleak, dislocation or limb occlusion have been reported after EVAR. This study hypothesized that the compliance mismatch between the graft and parent artery causes haemodynamic disturbances at the distal edge of the graft. Therefore, the potential for the graft to cause limb occlusion was assessed. A compliant phantom was fabricated. A circulatory loop was developed to run the fluid and generate a physiological flow waveform. Particle Image Velocimetry was utilised to capture fluid dynamics in the replica. The result showed a low velocity region at the graft trailing edge wall. The low velocity boundary layer thickness decreased downstream of the graft. A flow recirculation was initiated and increased in size during the mid-acceleration at the low velocity region. Shear stresses fluctuated at the trailing edge of the graft which is a risk factor for intimal thickening followed by graft or limb occlusion. It was concluded that this haemodynamic behaviour was due to the graft and parent artery compliance mismatch.