Giant Right Atrial Thrombi Formation Associated with Hemodialysis Catheter Placement in a Dog

A Cocker spaniel (7-year-old, female) was presented with one week of anorexia, halitosis, oral ulcer, intermittent vomiting, acute weight loss and 3-day history of oliguria. The patient was diagnosed with acute on chronic kidney disease and pancreatitis. Hemodialysis was continued three times a week (total 7 sessions) with improved clinical signs and kidney panel, but presented with another episode of abdominal distention, respiratory distress, and large bowel diarrhea. Echocardiography revealed nearly totally occlusive thrombus in the cranial vena cava, as well as a right atrial mass of approximately $2cm{\times}1cm$. The patient was treated with catheter removal, thrombolysis and anticoagulation therapy with recombinant tissue plasminogen activator. During anticoagulation therapy, size of atrial thrombus was not changed and heart function was not improved after treatment. Since clinical signs were deteriorated, the patient was euthanized by owner's request. Catheter-related giant thrombus in right atrium is a rare complication and treatment guideline for atrial thrombus does not exist. This case is first report of hemodialysis catheter-induced thrombus in Korea.