Aortic dissection: recognising the tear that kills — the AU GP framework

What aortic dissection is

Aortic dissection is the most time-critical cardiovascular emergency most GPs will ever encounter — and one of the most commonly misdiagnosed. A tear in the inner lining (intima) of the aorta allows blood to track between the wall layers, creating a false lumen that can propagate rapidly in either direction from the tear. Type A dissection, involving the ascending aorta, kills at approximately 1–2% per hour without emergency surgery. Without treatment, half of all patients with Type A dissection are dead within 48 hours.

Australia diagnoses approximately 3–5 aortic dissections per 100,000 people per year, though the true incidence is higher because many patients die before reaching hospital. Males aged 60–70 are most commonly affected. Younger patients with Marfan syndrome, Loeys-Dietz syndrome, bicuspid aortic valve, or a family history of thoracic aortic aneurysm form a distinct, often under-recognised group.

The GP’s contribution is recognition before the patient reaches hospital — and avoiding the error of treating a dissection as an acute coronary syndrome.

A. Core clinical — the AU general-practice framework

Risk factors

Per the European Society of Cardiology 2024 Aortic Diseases Guideline, hypertension is present in approximately 70% of aortic dissections and is the dominant modifiable risk factor. Additional risk factors include:

• Pre-existing aortic aneurysm — an aortic root or ascending aorta diameter ≥5.0 cm significantly increases dissection risk
• Bicuspid aortic valve — associated aortopathy occurs independently of valve function
• Connective-tissue disorders — Marfan syndrome (FBN1 mutation), Loeys-Dietz syndrome (TGFBR1/2), vascular Ehlers-Danlos syndrome (COL3A1), and familial thoracic aortic aneurysm (TGFB2, ACTA2 gene mutations)
• Stimulant drug use — cocaine and methamphetamine produce acute hypertensive surges that can precipitate dissection
• Prior cardiac surgery or aortic instrumentation
• Pregnancy and postpartum, particularly in the third trimester in people with underlying aortopathy
• Family history of dissection — a strong independent risk factor even without identifiable genetic syndrome
• Turner syndrome — associated with aortic coarctation and aortopathy

The clinical presentation

The hallmark of aortic dissection is sudden, severe pain that is maximal at its very first moment — a tearing, ripping, or knife-like quality, often described as the worst pain the person has ever experienced. This temporal pattern distinguishes it from myocardial infarction, where pain typically builds over minutes.

Per CSANZ and Heart Foundation Australia guidance, additional examination findings include:

• Pain location and migration: anterior chest pain (Type A); interscapular or back pain (Type B or descending propagation); abdominal pain when dissection reaches the abdominal aorta; migrating pain as it propagates
• Blood-pressure differential ≥20 mmHg between arms — indicates subclavian artery involvement
• Pulse deficit between limbs — limb malperfusion
• New diastolic murmur of aortic regurgitation — present in approximately 50% of Type A
• Syncope — from cardiac tamponade, hypovolaemia, or cerebrovascular involvement
• Neurological deficit — stroke (carotid involvement), paraplegia (artery of Adamkiewicz), Horner’s syndrome (sympathetic chain)
• Hypotension — indicates rupture, tamponade, or severe aortic regurgitation; carries the worst short-term prognosis

Approximately 60% of patients are hypertensive at presentation; 10–15% are hypotensive. About 5% present without pain (more common in older patients with prior aortic disease).

Stanford classification

Type	Location	Frequency	Initial management
Type A	Involves ascending aorta	~60%	Emergency cardiothoracic surgery
Type B	Descending aorta only	~40%	Medical management; TEVAR if complicated

Immediate GP management

Per Therapeutic Guidelines (eTG) and RACGP:

1. Call 000 immediately — request Category 1 transfer to the nearest tertiary centre with cardiothoracic surgery capability
2. Insert two large-bore IV cannulae; obtain ECG and portable chest X-ray without delaying transfer
3. Never give thrombolytics — even if ECG suggests inferior myocardial infarction (Type A can mimic right coronary artery occlusion); CT aortogram must precede any thrombolytic decision
4. Heart rate and blood-pressure control: target heart rate ≤60 bpm and systolic blood pressure 100–120 mmHg using IV beta-blocker first — esmolol infusion or labetalol boluses — before adding any vasodilator (giving a vasodilator first triggers a reflex tachycardia that worsens aortic wall stress)
5. IV morphine 2–4 mg for analgesia; repeat as needed
6. Position the patient with the head 30° elevated to reduce intracranial pressure if encephalopathy is present
7. Nil oral intake; position for transfer

B. Diagnosis — the traps and the tools

Why dissection is missed

Aortic dissection is misdiagnosed in 30–40% of cases on initial presentation, most often as acute coronary syndrome or pulmonary embolism. The International Registry of Acute Aortic Dissection (IRAD) documents that diagnostic delay is an independent predictor of mortality.

Clinical features that should raise suspicion even without classic tearing pain:

• Severe pain that was instantaneous (not building) at onset
• A hypertensive crisis with any new focal neurological, vascular, or cardiac findings
• Unexplained syncope or collapse in a patient with hypertension or known aortopathy
• New aortic regurgitation murmur without prior valvular disease history
• Limb ischaemia in the absence of peripheral arterial disease history

Investigations

Chest X-ray: may show a widened mediastinum, blurred aortic knob, or displaced aortic calcification. However, 10–15% of chest X-rays are normal — a normal result does not exclude dissection.

CT aortogram: the gold-standard investigation, with sensitivity and specificity exceeding 95%. It characterises the full aortic anatomy — location and extent of dissection, true versus false lumen, branch-vessel involvement, pericardial effusion, and aortic diameter — and directly informs the decision between surgery and endovascular repair.

D-dimer: extremely elevated in dissection. A very low D-dimer in a genuinely low pre-test probability clinical scenario has approximately 95% sensitivity as a rule-out adjunct, but it is a supplementary tool only — CT aortogram is required when clinical suspicion is present.

Bedside echocardiography: useful to identify proximal dissection flap, pericardial effusion, aortic regurgitation, and tamponade if CT is briefly delayed.

C. Treatment by type

Type A — surgical emergency

Without emergency surgery, in-hospital mortality for Type A dissection approaches 50% at 48 hours and 80% at one month. With surgery at a high-volume Australian cardiothoracic centre, in-hospital mortality is approximately 10–25%.

The standard operation replaces the ascending aorta with a synthetic graft. If the aortic root is involved, the valve is repaired or replaced (Bentall procedure). Coronary ostia may need reimplantation. Aortic arch repair adds complexity and risk.

Australian quaternary thoracic-aortic programmes — including Royal Prince Alfred Hospital (Sydney), Royal Melbourne Hospital, Princess Alexandra Hospital (Brisbane), Royal Adelaide Hospital, and Sir Charles Gairdner Hospital (Perth) — provide these services. Rural and remote transfer is coordinated through state retrieval services and the Royal Flying Doctor Service.

Type B — medical and endovascular management

Uncomplicated Type B is managed with strict haemodynamic control in a high-dependency or intensive-care setting, with close monitoring for complications.

Complicated Type B — defined by any of: persistent or recurrent pain, refractory hypertension, rupture, expanding false lumen, or end-organ malperfusion (visceral ischaemia, acute kidney injury, or limb ischaemia) — is treated with thoracic endovascular aortic repair (TEVAR). TEVAR deploys a stent-graft to cover the entry tear and redirect flow into the true lumen. Per the INSTEAD-XL trial, TEVAR improves five-year survival in appropriately selected Type B dissection.

Long-term management

All dissection survivors require lifelong specialist-coordinated management:

• Blood-pressure control: target systolic blood pressure <130 mmHg per ESC 2024; typical regimen combines a beta-blocker with an ACE inhibitor or angiotensin receptor blocker and a calcium channel blocker
• Surveillance imaging: CT or MR aortogram every 6 months in the first year, then annually — indefinitely
• Exercise modification: moderate aerobic exercise is encouraged; extreme isometric exercise, maximal-effort weightlifting, and activities involving prolonged Valsalva are avoided
• Cessation of stimulants: cocaine, methamphetamine, ephedrine, and stimulant-containing decongestants are absolutely contraindicated
• Smoking cessation: smoking accelerates aortic degeneration and progression

D. Australian operations

ACC/AHA 2022 and ESC 2024 guidelines are the primary evidence base. Australian specialist management follows CSANZ position statements and eTG clinical guidance.

Medications and PBS: long-term antihypertensives — beta-blockers, ACE inhibitors, angiotensin receptor blockers, and calcium channel blockers — are PBS-listed general-schedule items. Per Australian Medicines Handbook, drug selection is guided by comorbidities, tolerability, and the importance of sustained heart-rate control.

GP Chronic Disease Management Plan (GPCCMP): items 965 (preparation) and 967 (review) support coordinated long-term care, including allied-health referrals for cardiac rehabilitation, dietitian support, and psychological care if needed.

Genetic testing and familial cascade: in patients with syndromic features, age under 50 at dissection, or a family history of thoracic aortic disease, referral to clinical genetics is appropriate. RACGP guidelines support this pathway. MBS items 73297 and related codes provide rebated access to specific gene panels (FBN1 for Marfan, COL3A1 for vascular Ehlers-Danlos, TGFBR1/2 for Loeys-Dietz) via clinical genetics services. First-degree relatives of a confirmed heritable aortopathy should be offered echocardiographic screening.

Driving and fitness for work: Austroads Assessing Fitness to Drive standards require cessation of driving during the acute recovery phase. Return to driving requires cardiovascular stabilisation and specialist clearance. Commercial vehicle standards are stricter and require formal occupational health assessment.

E. Special populations

Pregnancy and aortopathy

Pregnant people with Marfan syndrome or other heritable aortopathies require multidisciplinary cardio-obstetric care from conception. An aortic root diameter exceeding 40 mm in Marfan syndrome substantially increases the risk of dissection during pregnancy; a diameter exceeding 45 mm is generally considered grounds for surgical repair before contemplating pregnancy. Beta-blockers — labetalol or metoprolol — are continued throughout pregnancy. The mode and timing of delivery are planned collaboratively with obstetrics, cardiology, and cardiothoracic surgery.

Young patients with syndromic features

Marfan syndrome is managed with annual echocardiographic monitoring from childhood. Beta-blocker therapy — atenolol or metoprolol — slows the rate of aortic root dilatation. Where beta-blockers are not tolerated, losartan is used. Prophylactic aortic root repair is considered at a root diameter of approximately 50 mm (lower thresholds apply with a family history of dissection at smaller diameters, or with rapid progression).

Older patients and frailty

In very elderly or frail patients with Type A dissection, the surgical risk may exceed the expected benefit. A multidisciplinary discussion — with the patient, family, and advance care planning — is appropriate in this context.

When to escalate

Any patient with clinical features consistent with aortic dissection should be transferred by ambulance to the nearest tertiary emergency department without delay — there is no appropriate GP-level management pathway, and no investigation available in-clinic that excludes the diagnosis.

After discharge from specialist management, contact the managing cardiologist or vascular surgeon urgently if:

• New or recurrent severe chest, back, or abdominal pain develops
• A limb becomes cold, pale, or pulseless
• A new neurological deficit appears
• Blood pressure cannot be controlled with current medications
• Syncope or presyncope occurs

What this article is and is not

This is general health information drawn from current guidelines — the ESC 2024 Aortic Diseases Guideline, ACC/AHA 2022 Aortic Disease Guideline, CSANZ, Therapeutic Guidelines (eTG), and Heart Foundation Australia. It is not personal medical advice and does not create a doctor–patient relationship. Decisions about specific investigations, medications, surgical timing, and surveillance intervals are made with the patient’s own cardiologist, cardiothoracic surgeon, and GP.

For Australian consumer-friendly information: HealthDirect — Aortic dissection, Better Health Channel, Heart Foundation Australia.

For acute emergency: call 000.

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Sources cited

1. ESC 2024 Aortic Diseases Guideline — Czerny et al. Eur Heart J 2024
2. ACC/AHA 2022 Aortic Disease Guideline — Isselbacher et al. Circulation 2022
3. CSANZ — Cardiovascular guidelines
4. Heart Foundation Australia
5. Therapeutic Guidelines (eTG)
6. RACGP
7. INSTEAD-XL — Nienaber CA et al. Circulation 2013
8. Australian Medicines Handbook
9. Austroads — Assessing Fitness to Drive
10. HealthDirect — Aortic dissection
11. Better Health Channel