Two cases of acute bioprosthetic mitral valve thrombosis immediately after mitral valve replacement.

Prosthetic valve thrombosis (PVT) is a rare complication, and most of PVT occurs in patients with mechanical valves. We present 2 extremely rare cases of acute bioprosthetic mitral valve thrombosis immediately after mitral valve replacement under veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and anticoagulant therapy. In Case 1, a 75-year-old woman underwent aortic valve replacement and mitral valve replacement with 23- and 29-mm bioprosthetic valves, respectively. On postoperative day 2, VA-ECMO was started because of hemodynamic compromise. At the initiation of VA-ECMO, transthoracic echocardiography indicated normal bioprosthesis function (Figure 1; see Movie I in the online-only Data Supplement). On postoperative day 9, transesophageal echocardiography revealed severely stenotic bioprosthetic mitral valve, but the bioprosthetic aortic valve was normal (Figure 2; see Movies II and III in the online-only Data Supplement). Emergent percutaneous mitral valvuloplasty was performed, resulting in partial improvement of hemodynamic state. On postoperative day 17, re-mitral valve replacement was performed. The left atrial side of the retrieved bioprosthetic valve leaflet was covered with thrombus, …