Elevated interleukin-6 levels in patients with asymptomatic left ventricular systolic dysfunction

Background Elevated interleukin-6 (IL-6) levels are present in patients with New York Heart Association (NYHA) class III and IV congestive heart failure (CHF) and are associated with a poor prognosis. We sought to determine whether elevated IL-6 levels are also present in patients with left ventricular (LV) dysfunction but without clinical symptoms. Methods Blood samples were obtained from the femoral artery of 58 patients who underwent cardiac catheterization for recognized clinical indications. In a subgroup of 44 patients, samples were also obtained from the femoral vein, the left main coronary artery, and the coronary sinus. Patients with prior coronary artery bypass surgery, recent acute coronary syndrome, or steroid therapy were excluded. All samples were obtained before heparin or contrast administration. IL-6 was measured by enzyme-linked immunosorbent assay and values are expressed in picograms per milliliter. Results Three groups of patients were identified: controls, no CHF, LV ejection fraction ≥0.55 (n = 32); asymptomatic LV systolic dysfunction, no CHF, LV ejection fraction