The conventional treatment of acute deep vein thrombosis (DVT) is anticoagulation and compression therapy, as recommended in the international guidelines. Anticoagulation prevents recurrent venous thrombosis, pulmonary embolism, and death. Compression therapy reduces the risk of developing long-term sequelae, that is, postthrombotic syndrome (PTS). Evaluation of systemic thrombolysis has shown effective thrombolysis and a likely reduction in PTS but at the cost of increased risk of bleeding complications. Catheter-directed thrombolysis (CDT) was introduced for rapid removal of thrombi and salvage of venous valves with less systemic thrombolytic effect, and is being offered to selected patients with iliofemoral DVT to prevent development of PTS. Case series have shown technical and thrombolytic success; however, no randomized studies have evaluated the long-term clinical effects of venous CDT. The aim of the CaVenT study is to investigate the role of adjunctive CDT by evaluating its clinical efficacy and safety compared with conventional treatment alone in patients with acute iliofemoral DVT.

The CaVenT study is an open, randomized, controlled, clinical trial. We plan to include 200 patients who will receive either CDT, in addition to conventional treatment, or conventional treatment alone. The primary outcome measures are patency at 6 months and prevalence of PTS at 2 years.

Implementation of the CaVenT study will be a contribution toward evidence-based medicine in the treatment of acute proximal DVT of the leg. Any documentation of improved functional outcome will have a significant impact on clinical practice for this patient group and may lead to a modification of existing international guidelines.