Epinephrine vs. Norepinephrine for Cardiogenic Shock

Study Questions:

What is the efficacy and safety of epinephrine and norepinephrine in patients with cardiogenic shock (CS) after acute myocardial infarction (AMI)?

Methods:

The investigators conducted a prospective, double-blind, multicenter, randomized study to assess the efficacy and safety of epinephrine and norepinephrine in patients with CS after AMI. The primary efficacy outcome was cardiac index evolution, and the primary safety outcome was the occurrence of refractory CS. Refractory CS was defined as CS with sustained hypotension, end-organ hypoperfusion and hyperlactatemia, and high inotrope and vasopressor doses. Associations between treatment group and adverse events were assessed by using logistic regression model. Odds ratios are presented with their 95% confidence intervals using the norepinephrine group as reference.

Results:

Fifty-seven patients were randomized into two study arms, epinephrine and norepinephrine. For the primary efficacy endpoint, cardiac index evolution was similar between the two groups (p = 0.43) from baseline (H0) to H72. For the main safety endpoint, the observed higher incidence of refractory shock in the epinephrine group (10 of 27 [37%] vs. norepinephrine 2 of 30 [7%]; p = 0.008) led to early termination of the study. Heart rate increased significantly with epinephrine from H2 to H24, while remaining unchanged with norepinephrine (p < 0.0001). Several metabolic changes were unfavorable to epinephrine compared with norepinephrine, including an increase in cardiac double product (p = 0.0002) and lactic acidosis from H2 to H24 (p < 0.0001).

Conclusions:

The authors concluded that in patients with CS secondary to AMI, the use of epinephrine compared with norepinephrine was associated with similar effects on arterial pressure and cardiac index and a higher incidence of refractory shock.

Perspective:

This randomized study comparing epinephrine and norepinephrine in patients with CS complicating AMI reports that epinephrine use was associated with very transient improvement in cardiac index, but with marked safety concerns including refractory shock. Furthermore, compared with norepinephrine, epinephrine administration also was associated with an increase in heart rate, prolonged acidosis, and lactatemia. At this time, norepinephrine appears to be the preferred vasopressor in patients with CS secondary to AMI. Additional studies are indicated to compare the myocardial energetic effects of various catecholamines and their impact on clinical outcomes in patients with CS in clinical settings other than AMI.

Clinical Topics: Acute Coronary Syndromes, Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: Acidosis, Lactic, Acute Coronary Syndrome, Arterial Pressure, Epinephrine, Heart Failure, Heart Rate, Hypotension, Myocardial Infarction, Myocardium, Norepinephrine, Shock, Cardiogenic, Vasoconstrictor Agents


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