The stated aims of treating acute deep vein thrombosis (DVT) are to prevent a pulmonary embolism, stop the clot from spreading, reduce the risk of a recurrence; they are less concerned with the late morbidity associated with post-thrombotic syndrome (PTS). In accordance with the French (Afssaps, 2009) and North American (ACCP, 2008) recommendations, anticoagulants (LMWH, heparin, AVK) form the cornerstone for treating DVT. These treatments appear to be far less effective in preventing post-thrombotic syndrome (PTS), associated with venous hypertension, residual occlusion, and with reflux caused by valve incompetence. Given that, the new aim is to optimise the prevention of PTS, the ACCP guidelines, unlike those of Afssaps, "suggest" for selected patients suffering from acute iliofemoral DVT, the use of both classic anticoagulants, and in situ percutaneous administration of thrombolytic drugs (recommendation grade 2B) and simultaneous correction of any underlying anatomical anomalies using angioplasty and stenting (recommendation 2C). Contemporary endovascular methods, referred to collectively as "facilitated" thrombolysis, combine low doses of rtPa or Urokinase administered locally, and the removal of the clot using various mechanical, rotating, rheolytic systems, or using ultrasound. The results of non-randomised, heterogeneous studies objectivised a lysis rate of 80%, a 50% lower risk of haemorrhage complications compared with systemic thrombolysis (<4%), and a clear reduction in treatment time (one-shot methods possible for procedures lasting less than 2 hours). This data ties in with the modern "open vein" concept which underpins the hope of an improvement in the late prognosis of acute DVT, through the removal of a clot, thereby improving permeability and valve integrity; this hypothesis is supported by the results at 24 months of a randomised CaVent objectifying absolute risk reduction of 15% in the thrombolysis in situ. The current randomised study (ATTRACT trial) comparing the combination of "facilitated thrombolysis" in addition to the usual treatment with the traditional treatment alone for acute iliofemoral DVT, the statistical power of which has been established (600 patients) to authenticate a reduction by a third in the number of PTS (CaVent trial, showing a 15% reduction rate of 24 months PTS in the thrombolysed group results expected in 2016), might, if the results are positive, lead to a profound change in the paradigms for the treatment of acute iliofemoral DVT.