EXPERIMENTAL INVESTIGATION OF HYPERCOAGULANT CONDITIONS ASSOCIATED WITH ANGIOGRAPHY

PURPOSE: To evaluate changes in blood coagulability after high-velocit y intravascular fluid injections under conditions relevant to angiogra phy. MATERIALS AND METHODS: In 101 rabbits, fluids were injected at 1, 000 psi (6,890 kPa) via a multiple-side-hole catheter in the abdominal aorta, while blood was simultaneously aspirated via a second downstre am catheter, The fluids injected included saline, contrast media, bloo d, tissue plasminogen activator, and heparin, The aspirate was evaluat ed for clotting time with an activated clotting time (ACT) device, for elevated levels of plasma hemoglobin to confirm capture of at least p art of the injection bolus in the sample, and sometimes for hematocrit or fibrin degradation products (FDP). RESULTS: A single high-pressure injection of 2 mL of saline briefly accelerated the ACT of a blood-sa line bolus (mean, 38% +/- 4), The mean volume of the hypercoagulable b olus was 15 mL. Systemic FDP levels became elevated within a few minut es after initial injection, suggesting activation of the fibrinolytic system by intravascular clot formation, Subsequent injections produced less hypercoagulability, probably reflecting the anticoagulant effect s of FDP, Pressure-injected contrast agents had anticoagulant effects, The ACT was accelerated by up to 80% after injection of blood that ha d remained within the catheter for 3-10 minutes, Glove powder or gauze lint from wiping the guide wire markedly accelerated intracatheter cl otting, Hypercoagulability after injection of clotting blood was parti ally prevented by injections with contrast agent and was completely in hibited by low-dose systemic heparinization. CONCLUSION: A hypercoagul able bolus may occur after angiographically relevant high-pressure flu id injections, The major contributing factors appear to be high jet ve locities and injection of small amounts of clotting blood, Heparinizat ion provides a simple and effective means of prevention.