Effects of milrinone on renal perfusion, filtration and oxygenation in patients with acute heart failure and low cardiac output early after cardiac surgery

Purpose: Early postoperative heart failure is common after cardiac surgery, and inotrope treatment may impact renal perfusion and oxygenation. We aimed to study the renal effects of the inodilator milrinone when used for the treatment of heart failure after weaning from cardiopulmonary bypass (CPB). Material and methods: In 26 patients undergoing cardiac surgery with CPB, we used renal vein catheterization to prospectively measure renal blood flow (RBF), glomerular filtration rate (GFR), and renal oxygenation. Patients who developed acute heart failure and lowcardiac output (cardiac index b2.1 L/min/m2) at 30min afterweaning fromCPB (n= 7) were given milrinone, and the remaining patients (n= 19) served as controls. Additionalmeasurements were made at 60 min after CPB. Results: In patientswith acute postoperative heart failure, before receiving milrinone, renal blood flow was lower (-33%, p b.05) while renal oxygen extraction was higher (41%, p b.05) compared to the control group. Milrinone increased cardiac index (21%, p b.001), RBF (36%, p b.01) and renal oxygen delivery (35%, p b.01), with no significant change in GFR and oxygen consumption compared to the control group. Conclusions: In patients with acute heart failure after weaning from CPB, the milrinone-induced increase in cardiac output was accompanied by improved renal oxygenation. Trial registration: ClinicalTrials.gov; identifier NCT02405195, date of registration; March 27, 2015, and NCT02549066, date of registration; 9 September 2015. (c) 2020 Elsevier Inc. All rights reserved.