Preprocedural anticoagulation does not reduce angioplasty heparin requirements

To determine whether continuous preprocedural heparin influences the need for anticoagulation during percutaneous transluminal coronary angioplasty (PTCA), we compared heparin requirements in patients therapeutically anticoagulated after continuous heparinization for ≥12 hours with patients not pretreated with heparin (controls). A Hemochron device was used to monitor the activated clotting time (ACT) values during the procedure. An ACT ≥300 seconds was used as a measure of optimal anticoagulation. Patients pretreated with heparin had significantly higher preprocedural ACT measurements (163 ± 31.5 vs 126 ± 13 seconds, p < 0.001) and partial thromboplastin time (PTT) measurements (46 ± 15 vs 25 ± 3 seconds, p < 0.001) than controls. While the amount of heparin needed to achieve an initial ACT >300 seconds was slightly greater in control patients (10,682 ± 1,852 vs 9,269 ± 2,993 units, p < 0.001), the total heparin required to maintain an ACT >300 seconds throughout the procedure was similar between the two groups (11,551 ± 3,181 units vs 12,136 ± 2,575 units, p = NS). Thus preprocedural anticoagulation does not significantly reduce total heparin requirements, and these patients should receive the same initial heparin regimen as patients not pretreated with intravenous heparin.