Mathematical model of apico aortic conduit in presence of steno-insufficiency

The revival of the apico aortic conduit has attracted new interest towards this alternative treatment for severe aortic stenosis not suitable to conventional valve replacement. The new automated coring and apical connector insertion kit released by Correx (Waltham, MA) made the procedure feasible on beating heart without cardiopulmonary bypass. However, little is known about the changes in the per- fusion of the epiaortic vessels after apico aortic conduit im- plantation, especially when severe aortic stenosis is associated with aortic valve insufficiency. We constructed a computational model to investigate the perfusion of the epiaortic vessels before and after apico aortic conduit implantation in the particular scenario of a patient with severe aortic valve stenosis associated each time with different grades of aortic insufficiency (mild, medium, moderate and severe). There were a total of eight combinations analyzed. In all simulations, there was a diminished flow through the epiaortic vessels the more severe the concomitant aortic insufficiency was. After apico aortic conduit implantation, there was an absolute augmentation of the median output in each epiaortic vessels compared with the same combination of mixed aortic valve disease before its implantation. Interestingly, retrograde flow from the descending aorta was trivial and did not contri- bute to the output improvement of the epiaortic vessels. The computational analysis suggested a protective effect, rather than a stealing phenomenon, by the apico aortic conduit to the cerebral perfusion.