We appreciate the comments of Boos and Lip regarding the role of other hemostatic factors in predicting arterial thrombotic events. Because of limitations in the length of our article,1 we had to be selective in the topics that we covered and chose not to focus on markers of coagulation activation or endothelial cell damage. The former include prothrombin fragment F1+2, thrombin–antithrombin complex, as well as D-dimer, while the latter include plasma von Willebrand factor (vWF) levels and soluble E-selectin. We agree that there are considerable data supporting vWF as a marker of endothelial injury as well as prospective data demonstrating that elevated vWF is associated with an increased risk for myocardial infarction after adjustment for inflammatory effects.2
In our review of hemostatic risk factors in predicting arterial thrombotic events, we primarily selected hemostatic factors that were measured in subjects at baseline rather than during an acute ischemic event. With respect to CD146-bearing circulating endothelial cells (CECs), the observations of Lee et al3 that concentrations of these cells rise in the setting of an acute coronary syndrome (ACS) and correlate with vWF are intriguing. Although statistically significant, we note that the adjusted odds ratios for elevated CECs 48 hours after clinical presentation with an ACS and major adverse cardiac outcomes at 30 days and 1 year are modest at 1.04 and 1.06, respectively.
Feinbloom D, Bauer K. Assessment of hemostatic risk factors in predicting arterial thrombotic events. Arterioscler Thromb Vasc Biol. 2005; 25: 2043–2053.
Morange PE, Simon C, Alessi MC, Luc G, Arveiler D, Ferrieres J, Amouyel P, Evans A, Ducimetiere P, Juhan-Vague I, on behalf of the PRIME Study Group. Endothelial cell markers and the risk of coronary heart disease: The prospective epidemiological study of myocardial infarction (PRIME) study. Circulation. 2004; 109: 1343–1348.
Lee KW, Lip GYH, Tayebjee M, Foster W, Blann AD. Circulating endothelial cells, von Willebrand factor, interleukin (IL)-6, and prognosis in patients with acute coronary syndromes. Blood. 2005; 105: 526–532.