A prospective cohort study of catheter-related thrombosis in cancer patients treated with 1 month of anticoagulation after catheter removal.

The duration of anticoagulation in patients with catheter- related thrombosis (CRT) is not standardized. This is a multiinstitutional prospective pilot study in patients with cancer and upper extremity CRT. Patients received therapeutic enoxaparin for 1 month after catheter removal. Incidence of recurrent thrombosis, hemorrhage, and postthrombotic syndrome (PTS) using the modified Villalta scale, and functional limitation using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire were assessed at months 1, 3, and 6 after catheter removal. Clopper-Pearson exact 95% confidence intervals (CI), Pearson correlations, and Skillings-Mack, and Wilcoxon signed ranks tests were done. Twenty-seven patients from three institutions were enrolled. Feasibility outcomes were not met. Seventy percent (n = 19) of the cohort had hematologic malignancies. Excluding two patients who were still on enoxaparin at study withdrawal, the median total duration of therapeutic enoxaparin was 32 [interquartile range (IQR) 30-52] days in the remaining 25 patients. During the 6 months after catheter removal, the incidence of recurrent thrombosis was 0% (n = 0/20, 95% CI 0-17%) and major hemorrhage was 5% (n = 1/20, 95% CI 0.13-25%). One patient (5%, 95% CI 0.13-25%) had PTS in the affected arm at any visit, and none had severe PTS. Higher PTS scores were associated with higher DASH scores. DASH scores at month 6 were significantly lower compared with month 1 (P = 0.0066). No deaths occurred. A multicenter pilot study of treatment with anticoagulation for 1 month after catheter removal did not meet feasibility outcomes but we found no recurrent thrombosis and a low incidence of PTS.