Background:Lack of fluoroscopic landmarks can make valve deployment more difficult in patients with absent aortic valve (AV)calcification.The goal of this article was to evaluate the feasibility and effectiveness oftranscatheter implantation of a valved stent into the AV position of a goat,assisted with a microcatheter which provides accurate positioning of coronary artery ostia to help valved stent deployment.Methods:The subjects were 10 healthy goats in this study.A microcatheter was introduced into the distal site of right coronary artery (RCA)through femoral artery sheath.A minimal thoracic surgery approach was used to access the apex of the heart.The apex of the left ventricle was punctured; a delivery catheter equipped with the valved stent was introduced over a stiffguidewire into the aorta arch.We could accurately locate the RCA ostia through the microcatheter placed in the RCA under fluoroscopy.After correct valve position was confirmed,the valved stent was implanted after rapid inflation of the balloon.The immediate outcome of the function of the valved stents was evaluated after implantation.Results:All ten devices were successfully implanted into the AV position of the goats.Immediate observation after the procedure showed that the valved stents were in the desired position after implantation by angiography,echocardiogram.No obstruction of coronary artery ostia occurred,and no moderate to severe aortic regurgitation was observed.Conclusions:When the procedure of transcatheter implantation of a balloon-expandable valved stent into the AV position of goats is assisted with microcatheter positioning coronary artery ostia,the success rate of operation can be increased in those with noncalcified AV.