Experimental Study of Methods for Treatment of Aortic Arch Aneurysm

Aortic arch aneurysm is a complex aortic pathology which requires coverage of one or more aortic arch vessels. This study presents an in-vitro investigation of the hemodynamic behavior, under stress heart rate (HR) conditions, of the aneurysmatic aortic arch and of the currently three common options for repair available for this pathology: i) open-chest surgical repair, ii) hybrid procedure which considered being a less-invasive than the surgical method, and iii) the chimney procedure which is a minimal invasive endovascular treatment. The experiments were carried out by particle image velocimetry (PIV) technique and a mock circulatory loop (MCL) system to enable testing the different approaches under systemic circulations of a normal human. The results from these experiments are compared to numerical results previously obtained by our group. Together, an assessment of both resting and stress HR conditions yield a complete picture of how the four cases influence the hemodynamic and potential complications.

According to the findings, in terms of blood supply (i.e., perfusion) to the brain and upper body, the surgery model has the highest perfusion. It also shows the strongest decrease in perfusion with elevated HR levels. Unlike the other models, the hybrid model exhibits moderate increases in perfusion with HR. It seems that the changes in perfusion with HR is affected mainly by the innominate artery arises from the aortic arch.

With respect to flow patterns, the flow patterns in the surgery model were smoothers with less distribution. The chimney model presented the most disturbed flow, with higher shear stress along the chimney graft during peak systole. The chimney procedure also may induce a "gutters" which, according to the relatively low calculated level of platelet activation, may allow blood leakage from the endograft sealed zone into the aneurysm.

The results of this study agree with clinical avoidances and may shade light on the hemodynamic factors and risk for complications, and provide important insights into ways to improve the endografts design and their placement technics.