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

Background Elevated interleukin-6 (IL-6) levels ore present in patients wit h New York Heart Association (NYHA) class III and IV congestive heart failu re (CHF) and are associated with a poor prognosis. We sought to determine w hether elevated IL-6 levels are also present in patients with left ventricu lar (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 v ein, the left main coronary artery, and the coronary sinus. Patients with p rior coronary artery bypass surgery, recent acute coronary syn drome, or st eroid therapy were excluded. All samples were obtained before heparin or co ntrast administration. IL-6 was measured by enzyme-linked immunosorbent ass ay and values are expressed in picograms per milliliter. Results Three groups of patients were identified: controls, no CHF, LV ejec tion fraction greater than or equal to0.55 (n = 32); asymptomatic LV systol ic dysfunction, no CHF, IV ejection Fraction <0.55 (n = 14), and CHF, pulmo nary edema (n = 12). IL-6 levels were higher at all sampling sites in both the asymptomatic LV systolic dysfunction and CHF groups compared with contr ols with the IL-6 levels inversely related to LV ejection fraction. Conclusions Elevated IL-6 levels are present in patients with LV dysfunctio n even in the absence of the clinical syndrome of CHF. These data suggest t hat IL-6 may be involved in the progression of subclinical LV dysfunction t o clinical CHF. IL-6 may be a marker of patients at risk For progression to clinical CHF or a novel target for therapeutic intervention.