Oral anticoagulation in peripheral vascular surgery: how intense, for how long, or at all?

To evaluate the influence of postoperative pharmacotherapy (antiplatelet therapy with acetylsalicylic acid (ASA) or oral anticoagulation) following various peripheral vascular surgical interventions (femoro-popliteal reconstruction, femoro-popliteotibial venous bypass;) two clinical series of patients were analysed (A1-2) and we made the hypothesis that adjuvant therapy may be beneficial. Thereafter two clinical trials were carried out (B1-2), to assess the value of postoperative antiaggregant and anticoagulant treatment. It was not possible to demonstrate any influence of ASA on improving patency at the iliaco-popliteal level or on patient survival. It was concluded that the ASA dosage of 1500 mg daily was too high, and produced severe side-effects, probably leading to insufficient patient compliance to therapy. In the B2 trial 130 patients received a femoro-popliteal above- or below-knee vein bypass, and were assigned to the therapy group (n = 66) and treated with anticoagulants or to the control group (n = 64) which received no therapy. During the follow-up, for a maximum of 10 years, the probability of bypass function, limb salvage and patient survival were significantly in favour of the treatment. The described single centre clinical trial B-2 produced in accordance with other trials a level II evidence in favour of postoperative pharmacotherapy. Level 1 trials assessing the direct comparison of antiaggregant versus anticoagulant therapy are underway, but results are unavailable yet, similarly the results of the Antithrombotic Trialist's Collaboration (ATT) are currently unknown.