Cardiovascular emergencies

Aortic dissection — condition overview

Overview and approach

Aortic dissection is an acute aortic syndrome caused by separation of wall layers; proximal involvement may need emergency surgery.

  • A tear in the inner layer of the aorta lets blood split the inner and middle layers. If blood goes through the outer wall it is often fatal.
  • Relatively uncommon; usually men in their 60s and 70s. Symptoms mimic other conditions, so diagnosis is often delayed, but early detection and treatment greatly improve survival.
  • Acute aortic syndromes include dissection (up to 80%), intramural haematoma and penetrating aortic ulcer, which sit on a continuum (1).
  • Type A (ascending aorta involved; more common and more dangerous; mortality rises about 1-2% per hour in the first 48 hours) versus Type B (descending aorta only) (1). Location, not injury type, drives treatment (1).
  • Cause: a weakened area of the aortic wall.
Assessment and clinical features

Abrupt severe chest/back pain, pulse/BP difference, neurological signs, aortic regurgitation and malperfusion; features may be incomplete.

  • Sudden severe chest or upper back pain, tearing or ripping, spreading to the neck or down the back; sudden severe abdominal pain; loss of consciousness; shortness of breath; stroke-like symptoms (vision change, speech difficulty, one-sided weakness); weak pulse in one arm or thigh; leg pain; difficulty walking.
  • Pain site follows the dissection: anterior chest, neck or jaw suggests ascending aorta; back or abdomen suggests descending (1).
  • Ascending dissection may cause MI, aortic regurgitation (diastolic murmur), pericardial effusion or shock (1).
  • Painless presentations: cardiac ischaemia, syncope (9%), heart failure (7%), stroke (6%) (1).
  • Chest pain plus neurology, or symptoms above and below the diaphragm, is dissection until proven otherwise (1).
  • Useful signs: focal neurology, diastolic murmur, pulse deficit (up to 30%, can be fleeting); arm BP difference above 20 mmHg is significant (1).
  • Risk factors: uncontrolled hypertension, atherosclerosis, aortic aneurysm, bicuspid aortic valve, coarctation, Turner, Marfan, Ehlers-Danlos, Loeys-Dietz, giant cell arteritis, male sex, age 60+, cocaine, pregnancy, high-intensity weightlifting (1). Also iatrogenic or traumatic (catheters, valve or aortic surgery) (1).
Differentials and investigations

Urgent senior assessment and definitive imaging selected by stability; ECG/troponin cannot safely exclude dissection.

  • Differentials: ACS, stroke, PE, pericarditis, aneurysm rupture, and other causes of acute chest or abdominal pain.
  • ECG is often normal (about 30% in Type A) and may show ischaemia; chest X-ray is insensitive (sensitivity 65%, specificity 86%) (1).
  • CT angiography is the gold standard (sensitivity above 95%). TOE is good for proximal dissection and is operator dependent; MRI is accurate but slow (1).
  • Bloods: FBC, UEC, LFT, troponin and cross-match (1).
  • D-dimer: ADD-RS of 0 with D-dimer below 500 ng/mL ruled out dissection with a miss rate of about 1 in 1000 in a meta-analysis. Apply only to a low-risk population (1).
Management and follow-up

Immediate cardiothoracic/vascular involvement, monitored analgesia and specialist-led haemodynamic control; treatment depends on anatomy and complications.

  • All dissections are surgical emergencies: discuss with cardiothoracic/vascular early (1).
  • Lower shear force: SBP below 120 mmHg and heart rate 60-80, with an arterial line. If arm pressures differ, use the higher one. Labetalol or another beta-blocker (e.g. esmolol) is usually first; a calcium channel blocker is an alternative if beta-blockers are contraindicated; give vasodilators like GTN only after beta-blockade (1).
  • Type A is managed surgically (mortality about 20% at 14 days with surgery versus about 50% without) (1).
  • Uncomplicated Type B is managed medically. Complicated Type B (about 25%: progression, malperfusion, uncontrolled hypertension) may need endovascular stenting (1).
  • Prevention: control BP (home monitoring), stop smoking, maintain healthy weight with a low-salt diet and exercise, wear a seatbelt, and tell your doctor about family history, connective tissue disorder or bicuspid valve. If you have an aneurysm, ask how often monitoring and surgery are needed. People with genetic risk may need medicines even if BP is normal.
Red flags and clinical pearls

Dissection can mimic ACS or stroke. Avoid reflex antithrombotic/thrombolytic treatment when the history raises concern for dissection.

  • Complications: death from severe bleeding, organ damage (kidney failure, bowel ischaemia), stroke, aortic regurgitation, and rupture into the pericardium (tamponade).
  • Think of dissection in syncope or malperfusion syndromes (1).
  • Rapid recognition matters because mortality climbs hourly in Type A (1).
References
  1. Acute Aortic Syndrome, Emergency Medical Education (resus.com.au)

Last updated from Sen’s notes on 9 October 2026.