Interleukin-6 correlates with hemodynamic impairment during dobutamine administration in chronic heart failure

Proinflammatory cytokines have been implicated in the pathophysiology of chronic heart failure. We determined mixed venous levels of interleukin-6 (IL6) in 18 heart transplant candidates before, 1, 4, and 24 h after initiation of dobutamine infusion (3 μg/kg/min) during hemodynamic evaluation. During the first 4 h of dobutamine, systemic vascular resistance decreased (1358 to 1024 dyn × s × cm−5, P = 0.01) while cardiac index (2.3 to 2.9 l/min/m2, P = 0.008) increased. Both returned to baseline after 24 h. IL6 was elevated at baseline compared to age-matched controls (1.5 (0/4.3) vs. 0 (0/0.5), P = 0.003). There was an increase in IL6 from 1.5 (0/4.3) to 3.6 (0.3/5.3) pg/ml after 24 h (P = 0.04). We found higher IL6 levels in the sicker half of patients as defined by pulmonary capillary wedge pressure >24 mmHg (P = 0.005), mean pulmonary arterial pressure ≥35 mmHg (P = 0.01), right atrial pressure >13 mmHg (P = 0.02), and heart rate ≥87/min (P = 0.02) as well as mean arterial pressure <82 mmHg (P = 0.005). In conclusion, in this pilot study IL6 correlates with the severity of chronic heart failure during low dose dobutamine infusion.