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DOREMI RCT – Milrinone vs Dobutamine for Cardiogenic Shock

September 10, 2021

Written by Meghan Breed

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In patients requiring inotropic support for treatment of cardiogenic shock, there was no difference between milrinone and dobutamine with respect to the primary composite outcome.

Why does this matter?
Cardiogenic shock is defined as a state of low cardiac output resulting in clinical and biochemical manifestations of hypoperfusion.  Cardiogenic shock has a high morbidity and mortality; therefore, beginning appropriate medical therapy (in this case inotropic support) in the emergency department is critical to patient care.

It’s a (cardiogenic) shock to the heart…now what?
In this double-blinded, randomized control trial, 192 patients were enrolled at a single center and randomized to receive inotropic support with either a dobutamine or a milrinone infusion.  Patients were eligible for enrollment if they were >18 years of age, admitted to a cardiac ICU and met the Society for Cardiovascular Angiography and Interventions (SCAI) definition for stage B, C, D or E cardiogenic shock.

Authors hypothesized a 20% lower event rate for the composite primary outcome for those receiving milrinone. Patients were well-matched with respect to age, race, sex, left ventricular function, coexisting medical conditions and stage of cardiogenic shock at time of enrollment (most patients were stage C).  A primary outcome event (in-hospital death from any cause, resuscitated cardiac arrest, receipt of a cardiac transplant or mechanical circulatory support, nonfatal myocardial infarction, TIA/CVA or initiation of renal replacement therapy) occurred in 49% of the Milrinone group and 54% of the Dobutamine group, but was not statistically significant.  Secondary outcomes, such as median total time receiving inotropic medications, receipt of non-invasive or invasive mechanical ventilation after randomization, median cardiac ICU length of stay or median hospital length of stay also did not reach statistical significance.  Given the infrequent use of pulmonary artery catheters, this study did not include analyses of changes in cardiac index, pulmonary capillary wedge pressure or systemic vascular resistance and thus relied on clinical assessment for enrollment and dose adjustments.   Because of the large difference in outcomes the authors intended to detect, this study may have been underpowered to see smaller effects.

As a brief review, milrinone and dobutamine are both considered “inodilators:” inotropes that are also vasodilators and therefore can worsen hypotension.  Milrinone is a phosphodiesterase inhibitor and increases cardiac inotropy and lusitropy.  Dobutamine is a synthetic catecholamine and acts on beta-1 and beta-2 receptors which increases cardiac output.  With that being said, in the emergency department, I would still consider starting an epinephrine infusion for inotropic support, particularly in patients with profound hypotension, especially since this is what providers tend to be more comfortable using.

Milrinone as Compared with Dobutamine in the Treatment of Cardiogenic Shock. N Engl J Med. 2021 Aug 5;385(6):516-525. doi: 10.1056/NEJMoa2026845.

What are your thoughts?