Sites of interleukin-16 release in patients with acute coronary syndromes and in patients with congestive heart failure

This study examines the source of elevated interleukin-6 (IL-6) levels in p atients with acute coronary syndrome (ACS) and congestive heart failure (CH F). IL-6 is elevated in the peripheral blood of patients with ACS and CHF, but it is not known if this proinflammatory cytokine is from a cardiac or e xtracardiac source. Blood samples were obtained from the femoral artery, fe moral vein, left main coronary artery, and coronary sinus in 57 patients du ring cardiac catheterization. IL-6 levels from 12 patients with ACS and 12 patients with CHF were compared with the IL-6 levels in 33 patients who had neither of these clinical conditions. Median IL-6 levels in the peripheral and coronary circulation were a minimum fivefold higher in patients with A CS or CHF relative to control patients. An elevated transcardiac IL-6 gradi ent (coronary sinus-left main level) was present in patients with ACS (medi an 5.2; 25th and 75th percentiles 3.9 and 29.3 pg/ml, respectively) compare d with control patients (median 0, -0.7 and 0.5 pg/ml; p <0.001), but not i n patients with CHF (median 0.4, -0.7 and 3.5 pg/ml; p = NS). Elevated IL-6 levels in patients with ACS derive from a cardiac source, presumably from "inflamed" coronary plaques and areas of myocardial necrosis, whereas eleva ted levels in patients with CHF are most likely the result of extracardiac production. (C)2000 by Excerpta Medica, Inc.