Thrombus in the distal aortic arch after apicoaortic conduit for severe aortic stenosis

We report an uncommon case of thrombogenesis in the distal aortic arch after apicoaortic conduit (AAC) for severe aortic stenosis (AS). A 71-year-old woman underwent AAC with a bioprosthetic valve for severe AS because of heavy calcification of the ascending aorta. Although anticoagulant therapy with warfarin was performed, a postoperative computed tomographic (CT) scan revealed a thrombus in the distal aortic arch. Cine magnetic resonance imaging (MRI) revealed stagnation of the blood flow at that site. Administration of warfarin was continued. A follow-up CT-scan showed a marked reduction of the thrombus at six months after the surgery. A follow-up MRI revealed that the antegrade flow through the native aortic valve was decreased at one year after the surgery. We suggest that thrombogenesis may occur after AAC because of stagnation of the blood flow and that the distribution of the blood flow may change during the follow-up period. Therefore, we recommend that postoperative anticoagulant therapy should be initiated immediately, even when a bioprosthetic valve is used.