Assessment of heparin anticoagulation during peripheral angioplasty.

The amount of heparin administered during peripheral angioplasty procedures is controversial and varies greatly among angiographers. Complications may result from both excessive and insufficient anticoagulation. The authors characterized the anticoagulant response to heparin in patients undergoing angioplasty by means of the activated clotting time (ACT). The ACT was measured in 64 patients who underwent lower extremity angioplasty. There was a linear relationship between heparin dose and ACT (P = .0001), but the slope of this relationship varied from patient to patient (R2 = .232). The response to heparin was blunted in one patient with thrombosis, but it was not exaggerated in patients with hematomas. Heparin anticoagulant response is highly variable, and heparin administration should be individualized according to ACT to produce a desired level of anticoagulation. Use of the ACT is a convenient and reproducible means of monitoring heparin administration and may increase safety and efficacy during peripheral angioplasty.