Successful Medical Management of Obstructive Mechanical Mitral Valve Thrombosis Using Low‐Dose, Ultraslow Infusion Thrombolytic Therapy: A Case Report

Obstructive mechanical valve thrombosis is a life-threatening complication that requires emergent diagnosis and intervention. We report the case of a 61-year-old man who presented with dyspnea. He had undergone mechanical aortic and mitral valve replacement in 2010. Admission laboratory results revealed subtherapeutic anticoagulation with an international normalized ratio of 1.09. Transthoracic and transesophageal echocardiography confirmed obstructive mechanical mitral valve thrombosis, with a 17 × 25 mm mass showing imaging features consistent with subacute thrombus and suggestive of concomitant pannus, which restricted the motion of one leaflet and increased the mean transmitral pressure gradient to 23 mmHg. Because of the patient's substantial surgical risk and the family's refusal of surgical intervention, the patient received low-dose, ultraslow thrombolytic therapy with alteplase administered as a continuous intravenous infusion of 25 mg over 25 h. The patient tolerated the regimen well, with no hemorrhagic or systemic embolic complications. Postintervention echocardiographic evaluation showed hemodynamic recovery (mean pressure gradient decreased to 3 mmHg). The patient was discharged on vitamin K antagonist therapy with planned close international normalized ratio monitoring. This case demonstrates that low-dose, ultraslow alteplase infusion may be a feasible treatment option for carefully selected patients with obstructive mechanical prosthetic valve thrombosis when surgery is considered high risk or declined.