Quantification of visceral perfusion and impact of femoral cannulation: in vitro model of aortic dissection

Abstract

Objectives: We aimed to simulate blood flow at an aortic dissection in an in vitro vascular model and assess the impact of the cannulation method on visceral perfusion.

Methods: An aortic-dissection model with an acrylic aortic wall and silicone intimal flap was developed to study visceral perfusion under various cannulation conditions. The primary tear was placed in the proximal descending aorta and the re-entry site in the left common iliac artery. A cardiovascular pump was used to reproduce a normal pulsatile aortic flow and a steady cannulation flow. Axillary and axillary plus femoral cannulation were compared at flow rates of 3-7 l/min. Haemodynamics were analysed by using four-dimensional flow magnetic resonance imaging.

Results: Axillary cannulation (AC) was found to collapse the true lumen at the coeliac and superior mesentery arteries, while combined axillary and femoral cannulation did not change the size of the true lumen. Combined axillary and femoral cannulation resulted in a larger visceral flow than did AC alone. When axillary plus femoral cannulation was used, the visceral flow increased by 125% at 3 l/min, by 89% at 4 l/min, by 67% at 5 L/min, by 98% at 6 l/min and by 101% at 7 l/min, respectively, compared to those with the AC only.

Conclusions: Our model was useful to understanding the haemodynamics in aortic dissection. In this specific condition, we confirmed that the intimal flap motion can partially block blood flow to the coeliac and superior mesenteric arteries and that additional femoral cannulation can increase visceral perfusion.

Keywords: Aortic dissection; Cardiovascular models; Haemodynamics; Perfusion.