Inflammatory markers (IM) have been associated with the risk of development of coronary artery disease (CAD) in nondiabetic patients (1). So far, no data are available concerning the relationship between angiographically documented CAD and inflammation in the diabetic population. Moreover, recently it has been suggested that in patients with silent myocardial ischemia (SMI), a condition frequently observed in diabetic populations (2), there is a higher production of anti-inflammatory cytokines (3), which suggests that the commonly described association between IM and CAD might not be found in patients with SMI. Therefore, we investigated these markers in diabetic patients who screened positive for SMI and who underwent coronary angiography.
All asymptomatic diabetic patients admitted to our department between January 1999 and April 2001 were considered for SMI screening using exercise-stress and/or dipyridamol 99Tcm-MIBI scintigraphy if they had at least two other major cardiovascular risk factors. A total of 422 patients were screened; 174 had a positive test, and 85 (83% with type 2 diabetes) had a coronary angiography performed by the same angiographer in our hospital. High-sensitivity C-reactive protein, fibrinogen, and leukocyte counts were measured in these 85 patients. Of the 85, 20 patients had no coronary stenoses, 19 had moderate stenosis (<70%), and 46 had severe stenosis (≥70%). The 46 patients with severe stenosis in at least one vessel showed higher levels of fibrinogen than the 20 patients without coronary stenosis and the 19 patients with moderate stenosis (4.10 ± 0.14, 3.40 ± 0.21, 3.49 ± 0.23 g/l; P = 0.004 and P = 0.03, respectively). A greater proportion of patients with severe stenosis were in the third tertile of CRP levels (i.e., >4.9 mg/l) in comparison with patients with moderate or no stenoses (42.9, 26.3, and 10.5%, respectively, P = 0.036). The same trend was noted for leukocyte counts. Among potential confounders (age, sex, smoking, type of diabetes, diabetes duration, HbA1c, hypertension, retinopathy, nephropathy, calculated creatinine clearance, and dyslipidemia), hypertension and albuminuria were the only ones to be significantly associated with CAD (P = 0.002 and P = 0.056, respectively). However, the associations between IM and severity of CAD remained significant when taking into account these variables.
These data provide evidence that severe epicardial stenosis is associated with a systemic inflammatory profile, even in diabetic patients with SMI (in the absence of unstable coronary syndrome). Further investigations are required to verify these observations and to subsequently determine whether these markers can be a useful tool to select a high-risk subgroup of asymptomatic diabetic patients with SMI who are likely to benefit from coronary angiography and subsequent revascularization.
References
Address correspondence to Antoine Avignon, Metabolic Diseases Department, Lapeyronie Hospital, 371 Av Doyen G Giraud, 34295 Montpellier Cedex 5. E-mail: [email protected].
