Acute Intraoperative Bioprosthetic Valve Thrombosis Immediately After Protamine Administration

Acute bioprosthetic valve thrombosis (BPVT) is considered a rare complication and has seldom been described. Moreover, acute intraoperative BPVT is exceedingly rare, and its management remains a major clinical challenge. Here, we report a case of acute intraoperative BPVT that occurred immediately after protamine administration. Major resolution of the thrombus and significant improvement of bioprosthetic function were observed after the resumption of cardiopulmonary bypass support for approximately 1 hour. Intraoperative transesophageal echocardiography is important for a prompt diagnosis. Our case describes the spontaneous resolution of BPVT after reheparinization, which might assist in the management of acute intraoperative BPVT.