Thrombin activity induced by balloon angioplasty of the coronary artery in Macaca fascicularis (cynomolgus monkey).

In this paper we address the question of whether balloon angioplasty induces thrombin action. In the studies reported here we measured fibrinopeptide A levels in a group of atherosclerotic monkeys undergoing coronary angioplasty. A blood collection catheter was introduced into the inferior vena cava through a femoral vein, and the angioplasty catheter introduced via the femoral artery. Heparin was administered immediately after insertion of the arterial catheter. Serial blood samples were collected for 20 min before angioplasty and for 10 min after angioplasty. Baseline levels of FpA were high, presumably in response to the trauma of introducing the catheters. After heparin administration the FpA concentration declined with a half-time of 1.1 min. In response to balloon inflation there was a clear increase in the concentration of FpA, despite the presence of a therapeutic concentration of heparin. The magnitude of the FpA rise was markedly different between animals, but was evident in the aggregate data after subtraction of background levels of FpA. By integration of the plasma FpA concentration curve, the amount of fibrinogen converted to fibrin in response to angioplasty was calculated to be approximately 0.4 mg/animal. We conclude that angioplasty induces significant activation of the coagulation system.