Treatment of acute iliofemoral deep venous thrombosis (DVT) with catheter-directed thrombolysis (CDT) has been performed in Denmark since 1999. The purpose of CDT is to dissolve thrombus and to restore the venous lumen as fast as possible and thereby save venous valve function and prevent postthrombotic syndrome. Danish studies have shown that treatment of acute iliofemoral DVT using CDT results in good patency, preserves venous valve function, reduces the frequency of PTS, and is associated with a higher quality of life.