Should We Perform Serial Ultrasonography to Tailor Anticoagulation Therapy for Patients with DVT?
Should We Perform Serial Ultrasonography to Tailor Anticoagulation Therapy for Patients with DVT?
Abstract & Commentary
By Joseph Varon, MD, FACP, FCCP, FCCM, Clinical Professor of Medicine and Professor of Acute and Continuing Care, University of Texas Health Science Center, Houston; Clinical Professor of Medicine, University of Texas Medical Branch, Galveston. Dr. Varon receives grant/research support from and serves on the speakers bureaus for The Medicines Company and EKR Pharma.
Synopsis: In patients with proximal deep vein thrombosis (DVT), tailoring the duration of oral anticoagulation based on serial ultrasonography reduces the rate of recurrent DVT. Prolongation of chronic anticoagulation may accelerate vein recanalization. Residual DVT on ultrasonography is a marker of hypercoagulability.
Source: Prandoni P, et al. Residual thrombosis on ultrasonography to guide the duration of anticoagulation in patients with deep venous thrombosis: A randomized trial. Ann Intern Med 2009;150:577-585.
This study was aimed at evaluating the optimal duration of oral anticoagulant therapy after an episode of lower extremity deep vein thrombosis (DVT) based on serial ultrasonography. This study was a randomized, multicenter, open-label trial that had independent and blinded assessment of the study outcomes. The study was designed to tailor the duration of anticoagulation. Patients were recruited between January 1999 and July 2003. Consecutive patients with DVT who had completed 3 months of oral anticoagulation therapy were eligible for inclusion. Patients with prior DVT or pulmonary embolism, immobility, need for chronic anticoagulation for some other reason, genetic coagulation deficiencies, or pre-existing malignancy were not eligible for inclusion. Once included in the study, patients were randomly assigned to fixed-duration or flexible-duration anticoagulation therapy with warfarin. The fixed group received 3 additional months of anticoagulation. The flexible group received anticoagulation based on ultrasonographic findings. If the vein had not recanalized, anticoagulation was continued and the ultrasono-graphy repeated at 3, 9, 15, and 21 months. If the vein had recanalized, anticoagulation was discontinued.
A total of 1020 patients were evaluated, of which 554 were eligible for inclusion in this study. Of them, 538 patients were randomized; 268 patients received fixed oral anticoagulant therapy and 270 received the flexible anticoagulation scheme. During follow-up, 78 patients (14.5% of the 538 patients) developed recurrent DVT. Of them, 46 occurred in the fixed-duration group and 32 in the flexible-duration group. Persistent residual thrombosis on the last ultrasound was seen in 29.5% of patients in the fixed-duration group as compared to 20% of the flexible-duration group (P = 0.02).
Commentary
Risk stratification of patients with DVT for recurrence of illness has been quite difficult for decades.1 The optimal duration of oral anticoagulation therapy has remained controversial at best.2 Primary care providers frequently wonder what the best duration of oral anticoagulant therapy should be. The study by Prandoni and coworkers reveals that anticoagulation can be tailored in patients with DVT based on serial ultrasonography. This study is interesting because it provides a simple and rational approach to the patient with DVT, in which simple ultrasonography helps determine duration of anticoagulation. In addition, this study affirms the fact that the presence of residual thrombus on follow-up ultrasono-graphy indicates hypercoagulability and a potential for further thrombosis, embolism, and even death.
References
1. Ost D, et al. Duration of anticoagulation following venous thromboembolism: A meta-analysis. JAMA 2005;294:706-715.
2. Siragusa S, et al. Residual vein thrombosis to establish duration of anticoagulation after a first episode of deep vein thrombosis: The Duration of Anticoagulation based on Compression UltraSonography (DACUS) study. Blood 2008;112:511-515.
In patients with proximal deep vein thrombosis (DVT), tailoring the duration of oral anticoagulation based on serial ultrasonography reduces the rate of recurrent DVT. Prolongation of chronic anticoagulation may accelerate vein recanalization. Residual DVT on ultrasonography is a marker of hypercoagulability.Subscribe Now for Access
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