Adjunctive Intracoronary Infusion of Antithrombin III During Percutaneous Transluminal Coronary Angioplast Results of a Prospective, Randomized Trial

Background Heparin needs the plasma protein antithrombin III to function as an inhibitor of thrombin, and local antithrombin III deficiency might therefore limit the antithrombotic effectiveness of heparin during percutaneous transluminal coronary angioplasty. Methods and Results In the present double-blind study, 615 consecutive patients undergoing percutaneous transluminal coronary angioplasty (PTCA), of a total of 713 stenoses, were prospectively randomized to receive a bolus injection of 15 000 U heparin followed by a continuous intracoronary infusion via the guiding catheter of either 250 U heparin per minute or 250 U heparin plus 25 U antithrombin III per minute during the procedure. Four clinical variables, 19 lesion-specific characteristics, and 16 procedure-related variables were evaluated. Procedural success was assessed by quantitative angiography; procedure-related ischemic complications were analyzed during in-hospital follow-up. Procedural success rates (<50% final diameter stenosis and no major ischemic complication) were similar, with 85% in the heparin group (n=324 patients) and 83% in the heparin+antithrombin III group (n=291 patients). Percent diameter stenosis after PTCA was 39±18% in the heparin group and 40±20% in the heparin+antithrombin III