Effect of aspirin and ticlopidine on plasma tissue factor levels in stableand unstable angina pectoris

Patients with unstable angina have an increased activation of the coagulati on system. Aspirin and ticlopidine given in combination may potentiate each other by the combination of different action mechanisms and may reduce the risk of coronary occlusion and clinical instability. Plasma tissue factor (TF) levels collected into the stenotic coronary artery may be on index of TF expression within the vasculature. In 160 patients undergoing angioplast y for a 81 +/- 5% coronary lesion, we measured TF in blood samples collecte d from a vein and from the coronary ostium. Immediately after and 10 minute s after the dilation procedures the samples were withdrawn also beyond the lesion. Heparin 150 U/kg was given as an anticoagulant. All patients were p retreated with 250 mg/day of aspirin. One hundred twenty patients were rand omly assigned ta receive 24, 48, or 72 hours of ticlopidine treatment (250 mg/twice daily). TF levels did not increase during angioplasty but there wa s a significantly higher TF expression in unstable than in stable patients, irrespective of the invasiveness of debulking procedures. When ticlopidine was given for 72 hours, TF levels were similar to normal laboratory valves both in stable and unstable patients. This combined antiplatelet pretreatm ent may be of benefit in unstable angina patients, with a favorable cost/be nefit ratio. (C)2000 by Excerpta Medica, Inc.