What is the inotrope of choice in myocardial infarction (MI) or recent myocardial infarction with hypotension?

From the Guidelines

Dobutamine is the inotrope of choice in myocardial infarction (MI) or recent MI with low blood pressure. It should be started at 2.5 mcg/kg/min and titrated up to 20 mcg/kg/min based on hemodynamic response, as recommended by recent guidelines 1. Dobutamine works primarily through beta-1 adrenergic stimulation, increasing cardiac contractility and cardiac output without significantly increasing heart rate or myocardial oxygen demand at lower doses. This makes it particularly suitable for patients with MI as it improves cardiac function while minimizing additional strain on the damaged heart.

Key Considerations

• In cases where dobutamine alone is insufficient, norepinephrine (starting at 0.01-0.03 mcg/kg/min) may be added to maintain adequate perfusion pressure, as suggested by studies 1.
• Continuous hemodynamic monitoring is essential during administration, watching for tachycardia, arrhythmias, or worsening ischemia.
• The goal is to use the lowest effective dose for the shortest duration necessary to maintain adequate tissue perfusion (mean arterial pressure >65 mmHg) while addressing the underlying cause of the MI and implementing definitive treatments such as revascularization.

Additional Options

• Other inotropes like milrinone and levosimendan may be considered in specific situations, but their use should be guided by the latest evidence and clinical judgment 1.
• The choice of inotrope and vasopressor should be individualized based on the patient's hemodynamic profile and underlying condition, as outlined in recent reviews 1.

From the Research

Inotrope of Choice in MI or Recent MI with Low BP

The choice of inotrope in patients with myocardial infarction (MI) or recent MI with low blood pressure (BP) is crucial for managing cardiogenic shock.

• Studies have compared the efficacy of milrinone and dobutamine in this setting 2, 3, 4, 5, 6.
• A study published in 1996 found that milrinone improved hemodynamic parameters, including cardiac index and pulmonary capillary wedge pressure, more effectively than dobutamine in patients with congestive heart failure following acute MI 3.
• However, a more recent study published in 2021 found no significant difference between milrinone and dobutamine in terms of primary composite outcome, which included in-hospital death, resuscitated cardiac arrest, and initiation of renal replacement therapy, in patients with cardiogenic shock 4.
• Another study published in 2021 found that acute MI was associated with increased rates of adverse clinical outcomes in cardiogenic shock, including mortality and initiation of mechanical circulatory support and renal replacement therapy 5.
• A retrospective review published in 2019 found that milrinone and dobutamine had similar effectiveness and safety profiles, but with differences in adverse events, such as arrhythmias and hypotension 6.

Comparison of Milrinone and Dobutamine

• Both milrinone and dobutamine are effective in improving hemodynamic parameters in patients with cardiogenic shock 3, 4, 6.
• However, milrinone may be more effective in reducing pulmonary congestion and improving cardiac index 3.
• Dobutamine may be associated with a higher risk of arrhythmias, while milrinone may be associated with a higher risk of hypotension 6.
• The choice of inotrope may depend on the individual patient's clinical profile and the presence of comorbidities 6.