Notten P, ten Cate-Hoek AJ, Arnoldussen CWKP, et al. - Considering that postthrombotic syndrome could be prevented with early thrombus removal by preserving venous function and restoring flow, researchers compared the benefit of additional ultrasound-accelerated catheter-directed thrombolysis for the prevention of postthrombotic syndrome vs standard therapy in patients with iliofemoral deep-vein thrombosis. This multicentre, randomized, single-blind, allocation-concealed, parallel-group, superiority trial was conducted in 15 hospitals in the Netherlands. They randomly assigned (1:1) either standard treatment with additional ultrasound-accelerated catheter-directed thrombolysis or standard treatment alone to 184 patients (aged 18–85 years) with a first-time acute iliofemoral deep-vein thrombosis and symptoms for no more than 14 days. Anticoagulant therapy, compression therapy (knee-high elastic compression stockings; 30–40 mmHg), and early ambulation comprised the standard treatment. They performed additional ultrasound-accelerated catheter-directed thrombolysis with urokinase with a starting bolus of 250,000 international units (IU) in 10 mL NaCl followed by a continuous dose of 100,000 IU/h for a maximum of 96 h through the Ekos Endowave-system. Outcomes revealed that the risk of postthrombotic syndrome 1 year after acute iliofemoral deep-vein thrombosis did not change in correlation to providing additional ultrasound-accelerated catheter-directed thrombolysis vs standard therapy alone. Although this trial is inconclusive, additional ultrasound-accelerated catheter-directed thrombolysis might have a moderate beneficial effect.