Aortic dissection vs Acute MI
How to tell Aortic dissection and Acute MI apart when a board question makes them look alike.
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Pulse or blood pressure differential between arms is a rapid clue for dissection.
Side by side
Abrupt tearing chest pain radiating to the back with pulse or blood pressure asymmetry strongly favors aortic dissection.
Pressure-like chest pain with ischemic ECG changes and dynamic troponin rise favors acute MI.
An intimal tear creates a false lumen that can obstruct branch vessels or rupture.
Coronary plaque rupture with acute thrombosis causes myocardial ischemic necrosis.
CT angiography shows an intimal flap separating true and false lumens, and chest radiograph may show widened mediastinum above 8 cm.
ST elevation at least 1 mm in 2 contiguous leads or rising troponin above the 99th percentile supports acute MI and reperfusion pathway activation.
The trap
Giving heparin and antiplatelets before excluding dissection can precipitate fatal bleeding into the mediastinum or pericardium. When pain is maximal at onset with back radiation and mediastinal widening, obtain urgent aortic imaging first.
The repair move
Next best step: start IV esmolol infusion to target heart rate below 60/min, add IV nicardipine if systolic blood pressure remains above 120 mm Hg, and obtain emergent CT angiography of the chest before anticoagulation. Consult cardiothoracic surgery immediately for type A dissection.
Try a free question
CoreA 58-year-old man has abrupt tearing chest pain to the back and unequal radial pulses. ECG shows nonspecific ST changes and troponin is minimally elevated. What is the next best step in management?
Show answer and explanation
Answer: A. Immediate CT angiography of the aorta with IV beta-blockade. Clinical suspicion for dissection requires urgent anti-impulse therapy and confirmatory aortic imaging before antithrombotics.
Why the other choices are tempting
- B. Wrong. Fibrinolysis can be catastrophic in dissection.
- C. Wrong. Antiplatelets do not address aortic rupture risk and may worsen bleeding.
- D. Wrong. Stress testing is contraindicated in acute high-risk chest pain.
- E. Wrong. High-risk vascular features mandate emergent evaluation.
Flashcards
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Which bedside sign most quickly separates aortic dissection from acute MI in chest pain?
Interarm pulse or blood pressure asymmetry strongly supports dissection.
What test confirms suspected aortic dissection in a hemodynamically stable patient?
CT angiography showing an intimal flap and false lumen.
Quick answers
What is the fastest way to tell Aortic dissection from Acute MI?
Pulse or blood pressure differential between arms is a rapid clue for dissection.
What is the key clue for Aortic dissection?
Abrupt tearing chest pain radiating to the back with pulse or blood pressure asymmetry strongly favors aortic dissection.
What is the key clue for Acute MI?
Pressure-like chest pain with ischemic ECG changes and dynamic troponin rise favors acute MI.
What is the common trap with Aortic dissection vs Acute MI?
Giving heparin and antiplatelets before excluding dissection can precipitate fatal bleeding into the mediastinum or pericardium. When pain is maximal at onset with back radiation and mediastinal widening, obtain urgent aortic imaging first.