What is the recommended dose of epinephrine (adrenaline) for intracoronary administration to manage no-reflow phenomenon during coronary angioplasty?

Intracoronary Epinephrine Dosing for No-Reflow Phenomenon

For no-reflow phenomenon during coronary angioplasty, intracoronary epinephrine should be administered at a dose of 50-100 μg, which can be repeated if necessary based on the clinical response.

Understanding No-Reflow Phenomenon

No-reflow is characterized by inadequate myocardial perfusion despite successful reopening of an epicardial coronary artery. It occurs in 10-40% of patients undergoing reperfusion therapy for STEMI 1 and is associated with:

• Microvascular embolization of thrombotic or atheromatous debris
• Reperfusion injury
• Microvascular disruption
• Endothelial dysfunction
• Inflammation and myocardial edema

The diagnosis is typically made when:

• Post-procedural TIMI flow is <3, or
• TIMI flow is 3 but myocardial blush grade (MBG) is 0 or 1, or
• ST resolution within 4 hours of the procedure is <70% 1

Pharmacological Management Algorithm

First-Line Agents (Class IIa Recommendation)

1. Intracoronary vasodilators 1:
   • Adenosine: 30-60 μg bolus
   • Calcium channel blockers (verapamil): 0.5-1 mg bolus
   • Nitroprusside: 50-100 μg bolus

When First-Line Agents Fail (Refractory No-Reflow)

1. Intracoronary epinephrine:
   • Initial dose: 50-100 μg 2, 3
   • Can be repeated if necessary
   • Total dose may range from 100-700 μg based on clinical response

Administration Technique

• Inject through a well-cannulated guiding catheter or preferably through a microcatheter into the distal coronary bed 4
• Local delivery in the distal coronary bed is more effective than guide-catheter delivery (63% vs 27.8% success rate) 4

Evidence for Efficacy

Recent evidence strongly supports the use of intracoronary epinephrine for no-reflow:

• Epinephrine achieves successful reperfusion in over 90% of patients with refractory no-reflow 3
• Epinephrine is superior to adenosine in achieving TIMI III flow (69.1% vs 52.7%, p=0.04) 3
• One-year MACE outcomes are significantly better with epinephrine compared to adenosine (11.3% vs 26.7%, p<0.01) 3
• No reported cases of malignant ventricular arrhythmias with intracoronary epinephrine 2

Safety Considerations

• Monitor for potential hemodynamic effects including tachycardia and hypertension
• Use with caution in patients with:
  • Underlying cardiac disease
  • Hyperthyroidism
  • Diabetes
  • Patients taking sympathomimetic agents, cardiac glycosides, or tricyclic antidepressants

Clinical Pearls

• The no-reflow phenomenon is associated with prolonged myocardial ischemia, severe arrhythmias, hemodynamic deterioration, and increased risk of clinical complications 1
• Reversing no-reflow is associated with favorable effects on left ventricular remodeling even without significant improvement in regional contractile function 1
• Consider using an intra-aortic balloon pump for hemodynamic support in cases of persistent no-reflow 1
• For severe cases, combination therapy (e.g., adenosine plus nitroprusside) may provide better improvement in coronary flow than either agent alone 1