Plasma fibrin D-dimer levels and risk of stable coronary artery disease: results of a large case-control study.

Increased levels of fibrin D-dimer are indicative of a hypercoagulable state, as found in acute coronary syndromes. Few well-controlled studies have assessed D-dimers in patients with stable coronary artery disease (CAD). We measured levels of D-dimers (in ng/mL by enzyme-linked immunosorbent assay) in 312 patients with angiographically proved CAD and stable angina pectoris and in 477 age- and sex-matched healthy blood donors. Demographic characteristics were assessed by a standardized questionnaire, and a complete lipid profile was performed for all subjects. In addition, a variety of other markers of hemostasis and inflammation were measured. The distribution of D-dimer levels was skewed to the right, and plasma median levels were higher in cases than in controls (median: 11.2 vs 2.8 ng/mL; P<0.001). In controls, correlations of D-dimer were found with fibrinogen, plasma viscosity, and interleukin-6. In logistic regression analysis, the age- and sex-adjusted odds ratio (OR) for the presence of CAD was 2.6 (95% confidence interval [CI], 1.9 to 3.5) when the highest quartile of the D-dimer distribution was compared with the combined lower 3 quartiles. The OR did not change appreciably after controlling for nonlipid risk factors (OR, 2.7; 95% CI, 1.9 to 3.9) and remained significant after further adjustment for other hemostatic parameters (OR, 2.4; 95% CI, 1.7 to 3.3) and markers of inflammation (OR, 2.1; 95% CI, 1.5 to 2.9). Plasma D-dimer levels are strongly and independently associated with the presence of CAD in patients with stable angina pectoris. These results support the concept of a contribution of intravascular fibrin to atherothrombogenesis.