Preventing increased fibrin formation during percutaneous transluminal coronary angioplasty through activated clotting time-controlled heparin treatment

Abstract

Background: A combination of heparin and aspirin is currently used to prevent coronary thrombosis in patients undergoing percutaneous transluminal coronary angioplasty (PTCA). However, the ideal heparin dosage for this use has not been established. In this study we examined a biochemical method for evaluating heparin regimens used during interventional procedures.

Methods: We measured the levels of fibrinopeptide A (FPA) in plasma and in 24-hour urine samples to examine the effects of heparin on fibrin formation in 37 patients undergoing PTCA and receiving two different dose regimens of heparin. A total of 18 patients received a standard dose of heparin (10,000 IU) immediately before the PTCA procedure (group 1); in another 19 patients the dosage was adjusted so that an activated clotting time (ACT) of greater than 300 seconds (20,500 ± 6600 IU) was established before the PTCA procedure began (group 2).

Results: In group 1 the plasma FPA level increased from 1.9 ± 1.0 ng/mL before to 4.2 ± 1.2 ng/mL after PTCA (P< 0.01) and levels in urine increased from 3.9 ± 1.6 ng before to 9.9±2.8 μg after PTCA (P< 0.01). In group 2 there was no significant change in the FPA level in plasma or urine with PTCA. Although no major bleeding complications occurred in either group, the hematocrit nadir after PTCA was lower in group 2 (P< 0.05).

Conclusions: Percutaneous transuminal coronary angioplasty may be associated with an increase in fibrin formation as measured by FPA levels in plasma or in 24-hour urine samples. Adjusting heparin dose with respect to ACT may prevent this increase in fibrin formation.