Evaluation of D-Dimer and CRP in cases of Atherosclerosis (CAD)

Fibrin D-dimer, a marker of cross-linked fibrin turnover, has also been shown in recent studies to be associated with the risk of future IHD in persons with and without baseline evidence of vascular disease. Local fibrin formation and lysis are part of the inflammatory response, and fibrin degradation products, including D-dimer, have been shown to have diverse effects on inflammatory processes and acute-phase responses, including neutrophil and monocyte activation; secretion of cytokines, including interleukin-6 and interleukin-1; and hepatic synthesis of acute-phase proteins, including fibrinogen and CRP. Interpreting D-dimer results Abstract— Elevated levels of C-reactive protein (CRP) and D-dimer (DD) have been associated with the presence and progression of various forms of atherosclerotic disease, particularly coronary heart disease. It is hypothesized that there is a relationship between elevated levels of baseline CRP and DD and progression of coronary arterial disease (CAD) in patients with symptomatic CAD. C-reactive protein (CRP), a marker of the reactant plasma protein component of the inflammatory response, has been associated with the risk of future ischemic heart disease (IHD), not only among patients with stable and unstable angina and high-risk subjects The current study is a prospective evaluation of this hypothesis. Plasma levels of C-reactive protein (CRP, a marker of the reactant plasma protein component of the inflammatory response) and of fibrin D-dimer (a marker of cross-linked fibrin turnover) has each been associated in recent studies with the risk of future ischemic heart disease (IHD). Previous experimental studies have shown that fibrin degradation products, including Ddimer, have effects on inflammatory processes and acute-phase protein responses. We therefore measured CRP and D-dimer levels in stored plasma samples from 100 men aged 49 to 77 years who were followed-up for incident IHD for an average of 45±4 months (mean±SD) and studied their associations with each other, with baseline and incident IHD, and with IHD risk factors. CRP and D-dimer levels were each associated with age, plasma fibrinogen, smoking habit, and baseline evidence of IHD. CRP was associated with D-dimer (r=0.21, P<0.00001). On univariate analyses, both CRP and D-dimer were associated with incident IHD. The incidence of IHD increased with CRP independently of the level of D-dimer (P=0.0002) and also increased with D-dimer independently of the level of CRP (P=0.048). In multivariate analyses, inclusion of D-dimer and conventional risk factors reduced the strength of the association between CRP and incident IHD; likewise, inclusion of CRP and conventional risk factors reduced the strength of the association between D-dimer and incident IHD.It is concluded that although these respective markers of inflammation and fibrin turnover show modest association with each other in middle-aged men, they may have additive associations with risk of incident IHD. Further larger studies are required to test this hypothesis