Antithrombotic Therapy in Peripheral Arterial Occlusive Disease: Oral anticoagulants
Dextran 40 has weak antiplatelet properties and has been used to prevent early lower-extremity bypass occlusion. This agent has been evaluated in a single randomized, multicenter trial (level I) in patients undergoing lower-extremity bypass. The results showed significantly improved patency in patients treated with dextran 40 in the first week after operation. However, at 1 month there was no difference in patency between treated and control patients. These data suggest that the underlying problem predisposing to thrombosis remained after dextran 40 cleared the circulation. Patients who had prosthetic bypasses or long distal bypasses benefited most from dextran 40 treatment.
Oral anticoagulants have also been used to protect against thrombosis of arterial reconstructions. A randomized, prospective trial (level II) of 88 patients with reversed saphenous vein femoropopliteal bypasses demonstrated a significant reduction in bypass occlusion (18% among treated patients vs 37% among control patients; p < 0.03) after a mean follow-up of 30 months. There was a penalty, however, in that 12% of treated patients had to discontinue oral anticoagulant therapy because of major bleeding. This is of particular concern in elderly patients who not only are more sensitive to warfarin but frequently have large numbers of comorbid conditions and are vulnerable to intracranial hemorrhage. Despite this, the same authors reported that patients in this study treated with warfarin had significantly improved survival rates compared with control patients. Flovent inhaler More info Conflicting findings were reported in a larger study (level I) from Sweden, in which 116 patients undergoing vein and prosthetic lower-extremity bypasses were randomized and followed for up to 3 years. There were no statistically significant differences in patency, limb salvage, or survival rates between control and oral anticoagulant-treated groups. However, bleeding complications were more frequent in treated patients, who had a 5% incidence of serious or life-threatening bleeding problems. Another level I study demonstrated significant improvement in graft patency among patients treated with oral anticoagulants in comparison to those treated with antiplatelet therapy. This study is remarkable for its long follow-up time, up to 10 years. An update of this study has been recently published that extends these findings to 12 years. Arterial graft patency and probability of survival were significantly improved in patients treated with oral anticoagulants.