Thrombogenic potential of human coronary atherosclerotic plaques

Higher levels of tissue factor (the initiator of blood coagulation) have be en found in coronary atherosclerotic plaques of patients with unstable coro nary artery disease, but it is not established whether they are associated with a different thrombotic response to in vivo plaque rupture. In 40 patie nts undergoing directional coronary atherectomy, prothrombin fragment 1 + 2 , a marker of thrombin generation, was measured in intracoronary blood samp les obtained proximally and distally to the coronary atherosclerotic plaque before and after the procedure. Before the procedure, plasma prothrombin f ragment 1 + 2 levels were significantly Increased across the lesion In pati ents with unstable, but not in those with stable, coronary disease (unstabl e, median Increase, 0.37 nM; range, -0.35-1.16 nM) (stable, median increase , -0.065 nM; range, -0.58-1.06 nM) (P = .0021). After plaque removal, an in crease in prothrombin fragment 1 + 2 across the lesion was observed only in patients with unstable coronary disease (unstable, median Increase, 0.25 n M; range, -1.04-4.9 nM) (stable, 0.01 nM; range, -0.48-3.59 nM) (P = .036)] . There was a correlation between the tissue factor content of the plaque a nd the increase in thrombin generation across the lesion (p = 0.33; P = .03 8). The higher tissue factor content found In plaques obtained from patient s with unstable coronary disease was associated with a local increase In th rombin generation, thus suggesting a link with the in vivo thrombogenicity of the plaque. (C) 2001 by The American Society of Hematology.