What is the management of aortic dissection causing inferior myocardial infarction (MI)?

Management of Aortic Dissection Causing Inferior Myocardial Infarction

Immediate surgical intervention is the definitive management for aortic dissection causing inferior myocardial infarction, as this represents a Type A dissection with coronary involvement requiring emergent aortic repair and coronary revascularization. 1, 2

Initial Stabilization and Diagnosis

Hemodynamic Control

• First step: Administer IV beta-blockers (labetalol preferred) to achieve:
  • Heart rate ≤60 beats per minute
  • Systolic blood pressure between 100-120 mmHg 1, 2
• Add vasodilators only after heart rate control is achieved
• Provide pain control with morphine sulfate
• Establish invasive arterial pressure monitoring in both arms

Diagnostic Approach

• Obtain ECG immediately - will show inferior ST-segment elevation 1, 3
• Critical warning signs that distinguish from primary MI:
  • Severe chest pain radiating to the back
  • Pulse deficits or blood pressure differences between arms
  • Diastolic murmur of aortic regurgitation
  • Difficulty engaging coronary ostia during attempted catheterization 4

Imaging

• Do not delay for definitive imaging if high clinical suspicion exists 1
• Preferred imaging modalities:
  • Transesophageal echocardiography (TEE) - can be performed bedside in unstable patients
  • CT angiography - if patient is stable enough for transport
  • Point-of-care ultrasound (POCUS) - may show pericardial effusion/tamponade and intimal flap 5

Critical Pitfalls to Avoid

1. Never administer thrombolytics - catastrophic in aortic dissection 3, 4
2. Avoid anticoagulation - can worsen bleeding and dissection 2
3. Do not delay surgical consultation - mortality increases ~1% per hour without intervention
4. Do not prioritize cardiac catheterization over surgical repair - catheterization may worsen dissection 4, 5
5. Do not miss signs of tamponade - may require emergent pericardiocentesis as a temporizing measure 1

Definitive Management

Surgical Approach

• Immediate surgical repair of the ascending aorta 1, 2
• Additional procedures based on findings:
  • Aortic valve resuspension or replacement if aortic root is involved
  • Coronary artery bypass grafting for the occluded right coronary artery 6
  • Complete replacement of dissected aorta if DeBakey Type II 1

Intraoperative Considerations

• Transesophageal echocardiography to guide repair
• Assessment of coronary ostia involvement
• Evaluation of aortic valve function

Postoperative Management

• Continue strict blood pressure control with IV medications initially, transitioning to oral agents
• Beta-blockers remain first-line therapy for long-term management
• Add ACE inhibitors or ARBs for blood pressure optimization 2
• Surveillance imaging at 1,3,6, and 12 months, then annually if stable 2

Special Considerations

• For patients with hemodynamic collapse before surgery, emergency pericardiocentesis may be needed, withdrawing just enough fluid to restore perfusion 1
• Temporary pacing may be required for bradyarrhythmias or heart blocks 6
• Defibrillation should be readily available for ventricular arrhythmias 6

The combination of aortic dissection with inferior MI represents one of the most lethal cardiovascular emergencies, with mortality rates that approach 100% without prompt surgical intervention. Early recognition and immediate transfer to a center with cardiac surgery capability is essential for survival.