Confusable diagnoses · PANCE / PANRE

Acute Coronary Syndrome vs Aortic Dissection

Written & clinically reviewed by Ryan Busch, PA-C · Updated August 2026 · Report an error

Acute Coronary Syndrome and Aortic Dissection are easy to mix up on the boards. Here's a side-by-side comparison — presentation, workup, imaging, and first-line treatment — drawn from our full outlines.

Acute Coronary Syndrome vs Aortic Dissection at a glance

  • Acute Coronary Syndrome: Spectrum of acute myocardial ischemia: unstable angina → NSTEMI → STEMI.
  • Aortic Dissection: Intimal tear with blood propagating in the aortic media — Stanford A surgery, Stanford B medical unless complicated.

Try two board-style questions on Acute Coronary Syndrome vs Aortic Dissection

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Question 1CardiovascularMedium
A 72-year-old male with diabetes mellitus (DM) and chronic kidney disease (CKD) (eGFR 35) has an non-ST-elevation myocardial infarction (NSTEMI). Troponin peaks at 4.2 ng/mL. He is stabilized on heparin, aspirin, and ticagrelor. Which of the following is the most appropriate timing of coronary intervention?
  • ACoronary angiography within 72 hours
  • BCoronary angiography within 2 hours
  • CCoronary angiography after stress testing
  • DCoronary angiography within 24 hours
Reveal answer & full explanation
Correct answer: D — Coronary angiography within 24 hours
  • ACoronary angiography within 72 hours
  • BCoronary angiography within 2 hours
  • CCoronary angiography after stress testing
  • DCoronary angiography within 24 hours✓

Why coronary angiography within 24 hours is correct

  • This patient has high-risk non-ST-elevation myocardial infarction (NSTEMI): elevated troponin (4.2 ng/mL), diabetes mellitus (DM), chronic kidney disease (CKD) with eGFR 35, and age over 70.
  • He is initially stabilized, so immediate angiography is not required; for stabilized high-risk NSTEMI (e.g., GRACE score >140), ACC/AHA guidelines rate an early invasive strategy with angiography within 24 hours as reasonable (Class 2a).

Why the others are wrong

  • Coronary angiography within 2 hours — immediate percutaneous coronary intervention (PCI) within 2 hours is reserved for very high-risk features: refractory ischemia, hemodynamic instability, severe arrhythmia, or acute heart failure (HF); this patient has none of those.
  • Coronary angiography within 72 hours — a delayed invasive strategy is for lower-risk NSTEMI; this patient's risk profile favors the earlier 24-hour window.
  • Coronary angiography after stress testing — stress testing is not appropriate in the setting of active NSTEMI with elevated troponin.

Additional high-yield points

  • CKD management perioperatively: IV isotonic saline hydration before and after contrast, minimize contrast volume, avoid nephrotoxins, hold metformin 48 hours post-contrast (risk of lactic acidosis if acute kidney injury (AKI) develops).
  • Thrombolytics are not used for NSTEMI — there is no ST elevation to treat.
Question 2CardiovascularEasy
A 68-year-old female with known coronary artery disease (CAD) presents with sudden onset tearing chest pain that is maximal at onset and radiates to the back. BP is 178/95 in the right arm and 142/88 in the left arm. CXR shows a widened mediastinum. CT angiography confirms a Stanford Type B aortic dissection. Which of the following is the most appropriate immediate management?
  • AEmergent thoracic endovascular aortic repair
  • BOpen surgical replacement of the descending aorta
  • CIV esmolol
  • DIntravenous nitroprusside as initial agent
Reveal answer & full explanation
Correct answer: C — IV esmolol
  • AEmergent thoracic endovascular aortic repair
  • BOpen surgical replacement of the descending aorta
  • CIV esmolol✓
  • DIntravenous nitroprusside as initial agent

Why IV esmolol is correct

  • This is a Stanford Type B aortic dissection (descending aorta only, no ascending involvement), confirmed by CT angiography.
  • Uncomplicated Type B is managed medically (unlike Type A, which requires emergency surgery).
  • Immediate medical management is an IV beta-blocker — esmolol (titratable) or labetalol — targeting heart rate below 60 bpm AND systolic blood pressure (SBP) 100-120 mmHg, which reduces aortic wall shear stress and prevents propagation.
  • If blood pressure remains elevated after heart rate is controlled, add a vasodilator (nicardipine or nitroprusside).

Why the others are wrong

  • Emergent thoracic endovascular aortic repair — Reserved for complicated Type B dissection (malperfusion, rupture or impending rupture, refractory pain or hypertension, rapid expansion); none of those features is described, so medical therapy comes first (right-procedure-wrong-indication).
  • Open surgical replacement of the descending aorta — Not first-line for uncomplicated Type B; thoracic endovascular aortic repair (TEVAR) is preferred over open surgery even when complicated (premature escalation).
  • Intravenous nitroprusside as initial agent — Vasodilating before rate control provokes reflex tachycardia that raises aortic wall shear stress (dP/dt); a vasodilator is added only after adequate beta-blockade (right-drug-wrong-sequence).

Additional high-yield points

  • Complicated Type B (indications for TEVAR): malperfusion (visceral, spinal cord, or limb ischemia), rupture or impending rupture, refractory pain or hypertension, and rapid aortic expansion.
  • ICU monitoring with serial CT imaging is required.
  • 5-year survival for uncomplicated Type B with medical management: approximately 80-90%.
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Side-by-side comparison

FeatureAcute Coronary SyndromeAortic Dissection
At a glanceSpectrum of acute myocardial ischemia: unstable angina → NSTEMI → STEMI.Intimal tear with blood propagating in the aortic media — Stanford A surgery, Stanford B medical unless complicated.
Classic presentationLevine's sign (clenched fist over sternum); cool/clammy skin; bradycardia in inferior MI.; Substernal chest pressure, tightness, or 'heaviness' (classic), often radiating to left arm, jaw, or back; Dyspnea, diaphoresis, nausea/vomiting; Atypical in women, elderly, diabetics: fatigue, epigastric pain, syncope, dyspnea without pain;…Sudden, severe, tearing or ripping chest pain that radiates to the back/interscapular region (anterior chest for type A, between scapulae for type B); Maximum severity at onset (unlike crescendo MI pain); Migratory pain following dissection propagation; Syncope (especially type A — tamponade, severe AR); Focal neurologic deficit…
Workup / key labsSTEMI: new J-point ST elevation in ≥2 contiguous leads, ≥1 mm in all leads other than V2-V3; in V2-V3 ≥2 mm in men ≥40, ≥2.5 mm in men <40, and ≥1.5 mm in women. With LBBB or a paced rhythm, apply Sgarbossa criteria; LBBB alone is not diagnostic. NSTEMI: rise and/or fall of troponin with ≥1 value above the sex-specific 99th percentile…Stanford A: involves ascending aorta (regardless of distal extent) — surgical emergency. Stanford B: confined to descending aorta distal to the left subclavian — generally medical management. DeBakey I: ascending and descending; II: ascending only; III: descending only.; CBC, BMP, type and crossmatch (massive transfusion likely);…
Imaging12-lead ECG within 10 minutes of arrival — repeat every 15-30 min if initial nondiagnostic; Portable CXR (look for pulmonary edema, widened mediastinum to exclude aortic dissection); Bedside echo if hemodynamic instability or mechanical complication suspectedCT angiography of chest/abdomen/pelvis — first-line in hemodynamically stable patients (defines extent, identifies branch involvement, planning); Transesophageal echocardiography — bedside option for unstable patients or those who cannot undergo CT; MR angiography — alternative when iodinated contrast contraindicated; Transthoracic…
First-line treatmentAspirin 325 mg chewed immediately (irreversible COX-1 inhibition blocks platelet thromboxane A2); P2Y12 inhibitor (blocks the platelet ADP receptor; clopidogrel and prasugrel are irreversible prodrugs, ticagrelor is reversible) loading dose: ticagrelor 180 mg, clopidogrel 600 mg, or prasugrel 60 mg (prasugrel only if known anatomy…ABCs, 2 large-bore IVs, type and crossmatch, ICU admission; AGGRESSIVE blood pressure and heart rate control FIRST — target SBP <120 mmHg (or the lowest BP that maintains end-organ perfusion) and HR 60-80 bpm per 2022 ACC/AHA (ESC guidance uses HR ≤60); IV beta-blocker FIRST to blunt reflex tachycardia: esmolol load 0.5 mg/kg then…

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Full outlines

Acute Coronary Syndrome (ACS) Aortic Dissection All 514 diagnoses

Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.