Prophylaxis of central venous catheter-related thrombosis with minidose warfarin in patients treated with high-dose chemotherapy and peripheral-blood stem-cell transplantation: retrospective analysis of 228 cancer patients.

Patients with a central venous catheter (CVC) undergoing high-dose chemotherapy (HDC) followed by peripheral-blood stem-cell transplantation (PBSCT) for malignancies are at high risk of thrombosis, but the use of anti-coagulant prophylaxis remains debatable in this setting of patients. We analyzed the efficacy and the safety of minidose warfarin in 228 patients in whom CVCs had been placed and who had received 292 HDC courses of therapy. The catheters remained in place for a mean of 173 (range 40-298) days. All patients received prophylactic oral warfarin in the fixed dose of 1 mg/day starting on the day of CVC insertion. Prophylaxis was interrupted during aplasia when platelet counts fell below 50,000/dL. There were no toxic deaths related to the prophylaxis. Overall there were 4 thrombotic events. Three occurrences were directly related to the catheter, while the remaining event was a deep saphenous-vein thrombosis. A number of potential predictive factors were analyzed for their impact on thrombotic events without finding any significant correlation. Four episodes of bleeding occurred, with each of these individuals having a normal INR but a platelet count below 50,000/dL. Minidose warfarin is effective and safe to use for preventing thrombotic events in this setting of patients.