Abstract 2422: Short Term Effects of Milrinone on Biomarkers in Severe Heart Failure
Introduction: Inotrope use is associated with adverse outcomes in heart failure (HF), raising concern that it may cause or accelerate myocardial injury/damage. Whether biomarkers of myocardial necrosis, stretch, inflammation and apoptosis change in response to inotrope initiation is not known.
Methods: Ten patients with severe HF and cardiac index < 2.0 L/m/M2 who were planned to receive intravenous milrinone were studied. All patients were at bed rest in cardiac intensive care unit. Blood was drawn immediately before initiation of milrinone and after 24 hours of continuous infusion. Milrinone dosing was at the discretion of the patient’s attending physician (0.375 –0.5 mcg/kg/min were used). Blood samples were immediately centrifuged, plasma aliquoted, and frozen at -70°C. Troponin I (TnI), Myoglobin, N-terminal pro-BNP (NTproBNP), interleukin 6 (IL6), Tumor Necrosis Factor α (TNF α), soluble Fas (sFas), and Fas ligand (FasL) levels were measured. TnI levels were replicated to assess precision of measurement, yielding a correlation coefficient > 0.995 and power > 90% to detect a mean difference as small as 0.02 ng/ml. Statistical comparisons were made between baseline levels and 24 hour levels using the paired t-test. P values < 0.05 were considered significant.
Results: Baseline mean biomarker levels, 24 hour levels, absolute change, percent change, and associated p-values are shown in the Table⇓. Troponin I was elevated at baseline in all patients (range 0.0205– 0.56 ng/ml). There was no significant change in TnI after 24 hours of milrinone compared to baseline. There were significant improvements in NTproBNP, IL6, TNF α, sFas, and FasL.
Conclusions: In this sample of patients with severe HF and reduced cardiac output, all had elevated troponin at baseline, consistent with ongoing myocardial damage. Initiation of milrinone therapy did not result in changes indicative of accelerated myocardial injury, and was associated with salutary effects on other markers.
This research has received full or partial funding support from the American Heart Association, Midwest Affiliate (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, South Dakota & Wisconsin).