Coronary angioplasty in patients with unstable angina, with special reference to preceding treatment with antithrombin III and heparin

Seventy-nine patients undergoing percutaneous transluminal coronary angioplasty (PTCA) for unstable angina were analyzed with respect to preceding antithrombin treatment; group I comprised patients (n = 26) without antecedent antithrombin therapy; group II, patients (n = 30) with heparin infusion for greater than or equal to 24 h, and group III patients (n = 23) with ongoing heparin infusion and given antithrombin III concentrate immediately before the procedure because of plasma antithrombin III <85%. Immediate results were 89% (70 of 79) angiographic success, five (6%) subacute occlusions (two subsequent non-Q wave infarctions), no emergency coronary artery bypass grafting (CABG), and no immediate mortality. There were no differences between the groups. From discharge to 4 months, one patient died, one had a nonfatal infarction, and 24 (30%) had repeated PTCA or CABG. The cumulative 4-month event rate was 11 of 26 (42%) in group I, 10 of 30 (33%) in group II, and 7 of 23 (30%) in group III (NS). During PTCA, heparin bolus administration was guided by activated clotting time (ACT), aiming at>300 s. Baseline ACT was significantly less in patients not treated with heparin (129 +/- 34 s in group I vs. 179 +/- 38 and 162 +/- 29 s in groups II and III, respectively; p < 0.05), but during the procedure, patients from all groups required the same amount of heparin (13,900 +/- 4,800, 13,000 +/- 6,800, and 13,000 +/- 5,700 IU, respectively; NS) to reach similar maximum ACT levels (334 +/- 36, 312 +/- 32, and 319 +/- 44 s, respectively; NS). Patients receiving warfarin (n = 8) responded with a higher ACT (456 +/- 110 s; p < 0.05) on lower doses of heparin (10,000 +/- 3,800 IU). In conclusion, patients with unstable angina receiving individualized antithrombotic therapy can be successfully treated with PTCA, with an acute complication rate and long-term results comparable with those expected in patients undergoing elective procedures. The value of antithrombin III substitution must be evaluated in randomized trials. Preprocedural heparin infusion does not reduce the need of extra heparin during the procedure.