A native
arteriovenous fistula is the first choice for
hemodialysis access. Despite improved
catheter designs and the use of internal jugular veins, thrombotic complications still occur when tunneled
central venous catheters are used as an alternative. Although right atrial
thrombus (RAT) is a well-characterized complication of long-term central venous cannulation, particularly when used for
parenteral nutrition and
chemotherapy in pediatric practice, only 9 reported cases previously have been associated with the long-term use of
central venous catheters for
hemodialysis. We report five cases of RAT seen at our unit between 1994 and 1998 in patients who had been dialyzed using tunneled
catheters. In four of five cases, the diagnosis was made during the investigation of
hemoptysis or
dyspnea. In the fifth case, a screening transthoracic echocardiogram revealed the
thrombus. Three of five of the patients suffered pulmonary emboli, and a fourth patient had an unexplained electromechanical dissociation
cardiac arrest without definite evidence of pulmonary
embolus. Our experience suggests that anticoagulated patients with RAT remain at risk of
pulmonary embolism. One of our patients successfully underwent atrial
thrombectomy. In four of five of our cases and four of nine cases in the literature, the
central venous catheter tip was within the right atrium. Positioning of the
central venous catheter tip low down in the superior vena cava or in the right atrium has been advocated to improve dialysis adequacy and to reduce the incidence of
catheter thrombosis. However, placement of the
catheter tip within the right atrium may be associated with an increased risk of RAT.