What vasopressor would you recommend first for a patient with ST-Elevation Myocardial Infarction (STEMI) if hypotension warranted its use?

Vasopressor Recommendation for STEMI with Hypotension

For STEMI patients requiring vasopressor support due to hypotension that does not resolve after volume loading, norepinephrine should be used as the first-line vasopressor agent.

Initial Management Algorithm

Before initiating any vasopressor in STEMI with hypotension, the following sequence must be followed:

• Rapid volume loading with IV infusion should be administered first to patients without clinical evidence of volume overload 1
• Correct any rhythm disturbances or conduction abnormalities that may be causing the hypotension 1
• Only after these interventions should vasopressor support be initiated if hypotension persists 1

Why Norepinephrine is First-Line

While the ACC/AHA STEMI guidelines do not specify a particular vasopressor by name, they clearly recommend "vasopressor support" for hypotension unresponsive to volume loading 1. Norepinephrine is the logical first choice based on the following evidence:

• Norepinephrine is recommended as the first-choice vasopressor in the 2017 Surviving Sepsis Campaign guidelines with strong recommendation and moderate quality evidence 1
• The FDA-approved indication for norepinephrine (LEVOPHED) specifically includes acute hypotensive states and explicitly mentions its use "as an emergency measure when intraaortic pressures must be maintained to prevent cerebral or coronary artery ischemia" 2
• Norepinephrine can be administered before and concurrently with blood volume replacement when emergency maintenance of intraaortic pressure is needed to prevent coronary ischemia 2

Dosing and Administration

Initial dosing of norepinephrine:

• Start with 8-12 mcg/min (2-3 mL/min of standard 4 mcg/mL dilution) 2
• Target mean arterial pressure of 65 mmHg or a systolic blood pressure of 80-100 mmHg 1, 2
• In previously hypertensive patients, raise blood pressure no higher than 40 mmHg below the preexisting systolic pressure 2
• Average maintenance dose ranges from 2-4 mcg/min (0.5-1 mL/min) 2

Critical Considerations for STEMI Patients

The STEMI context requires special attention:

• Patients with pulmonary congestion and marginal or low blood pressure often need circulatory support with inotropic and vasopressor agents and/or intra-aortic balloon counterpulsation 1
• If low cardiac output is the primary problem (manifested by cold extremities, cyanosis, oliguria, or decreased mentation), dobutamine infusion is often the initial pharmacological intervention 1
• Intra-aortic balloon counterpulsation should be performed in patients who do not respond to other interventions, unless further support is futile 1

Common Pitfalls to Avoid

Do not delay vasopressor initiation excessively:

• Profound and durable hypotension is an independent factor of increased mortality 3, 4
• Early administration of norepinephrine increases cardiac output and improves microcirculation while avoiding fluid overload 3, 4
• Consider early norepinephrine when diastolic blood pressure is ≤40 mmHg or when the diastolic shock index (heart rate/diastolic BP) is ≥3 4

Distinguish between vasodilatory shock and cardiogenic shock:

• If the primary problem is pump failure (evidenced by pulmonary congestion or signs of low output), inotropic support with dobutamine may be more appropriate than pure vasopressor therapy 1, 5
• Beta-blockers or calcium channel blockers should not be administered to patients in a low-output state due to pump failure 1

Second-Line Options

If hypotension persists despite adequate norepinephrine:

• Add vasopressin (0.03 units/min) to raise MAP or decrease norepinephrine dosage 1
• Add epinephrine when an additional agent is needed to maintain adequate blood pressure 1
• Dopamine should only be used in highly selected patients with low risk of tachyarrhythmias and absolute or relative bradycardia 1