Cardiovascular · Topic 38 of 48

Aortic Dissection

Cardiovascular · acute aortic syndrome

Aortic Dissection

A tear that splits the aortic wall. Beta-block first to SBP under 120 and HR 60–80; type A goes to emergency surgery.

Key numbers

IV beta-blocker to SBP under 120SBP < 120 mmHg

Type A: emergency surgical repair1–2% mortality/hour

01 · Defined byStanford A involves the ascending aorta

Stanford classification: type A involves the ascending aorta wherever the tear began; type B is confined to the descending aorta distal to the left subclavian artery. The type decides surgery versus medical therapy.

02 · DoIV beta-blocker to SBP under 120

Start IV beta-blockade immediately for impulse control: target systolic BP < 120 mmHg (or the lowest pressure that keeps brain, heart and kidneys perfused) and heart rate 60–80/min.

03 · DoType A: emergency surgical repair

Acute type A dissection needs emergency open repair with an early cardiothoracic surgery consult: untreated mortality is about 1–2% per hour from symptom onset and over 50% at 1 month.

Causes & risk factors

Why it happens

Hypertension and connective tissue diseaseHypertension contributes in more than two-thirds of cases; other risks are Marfan, Ehlers-Danlos and Loeys-Dietz syndromes, bicuspid aortic valve, coarctation, Turner syndrome, cocaine, and aortic catheterization or valve surgery.

Presentation

What you'll see

Abrupt tearing chest or interscapular pain must knowClassic dissection pain is abrupt, excruciating, tearing or ripping chest or interscapular pain that may migrate as the tear extends; 20–30% have pulse deficits, and limb blood pressures may differ (sometimes by > 30 mmHg).

Chest x-ray: widened mediastinum, left effusionThe chest radiograph often shows a widened mediastinum, sometimes with a localized bulge at the origin, and a left pleural effusion is common; a suggestive film prompts immediate CTA or TEE.

Diagnosis & monitoring

Work-up

Lifelong beta-blocker and serial CTAfter any acute aortic syndrome, continue a beta-blocker long term and image with CT (or MRI) at 1, 6 and 12 months, then yearly if stable — the aorta is followed for life.

Do right now

In this order

First moves

IV beta-blocker to SBP under 120SBP < 120 mmHg

→

Never give a vasodilator before beta-blockade

→

CT angiography first; TEE if unstable

→

Type A: emergency surgical repair1–2% mortality/hour

Why each step

IV beta-blocker to SBP under 120Start IV beta-blockade immediately for impulse control: target systolic BP < 120 mmHg (or the lowest pressure that keeps brain, heart and kidneys perfused) and heart rate 60–80/min.

Never give a vasodilator before beta-blockadeAdd a vasodilator such as nitroprusside only after beta-blockade (or a nondihydropyridine calcium channel blocker): a vasodilator alone causes reflex sympathetic activation that raises contractility and aortic shear stress, extending the dissection.

CT angiography first; TEE if unstableCT angiography is the usual first imaging test (intimal flap with two lumens confirms it); bedside TEE (97–99% sensitive, no contrast) suits the unstable patient; MRA is reserved for stable, subacute presentations.

Type A: emergency surgical repairAcute type A dissection needs emergency open repair with an early cardiothoracic surgery consult: untreated mortality is about 1–2% per hour from symptom onset and over 50% at 1 month.

Management

Orders

Uncomplicated type B: medical therapyUncomplicated, stable type B dissection is treated medically; endovascular stent grafting (TEVAR) is indicated for complications — malperfusion, rupture, extension, rapid aortic enlargement, or refractory pain or hypertension.

Esmolol, labetalol or metoprolol IVFirst-line IV agents are esmolol, labetalol or metoprolol; use IV diltiazem or verapamil if beta-blockers are not tolerated, and add nitroprusside only if SBP stays above about 110 mmHg.

ICU, arterial line, crossmatch 4–6 unitsAdmit to the ICU with an arterial line and urinary catheter, treat pain, type and crossmatch 4–6 units of packed red cells when surgery is likely, and intubate the hemodynamically unstable patient.

Red flags & don'ts

Avoid harm

Malperfusion: stroke, MI, gut, kidney, cord complicationBranch-vessel malperfusion can cause stroke, MI, mesenteric ischemia, renal failure, limb ischemia or paraplegia — usually from the false lumen obstructing a branch; malperfusion defines a complicated type B dissection.

Hypotension: tamponade, rupture or acute AR complicationIn type A, retrograde extension causes acute aortic regurgitation, coronary occlusion and hemopericardium with tamponade; hypotension with tachycardia suggests active bleeding or rupture into the pericardium or left pleural space.

The rules

Know these

Low ADD-RS plus negative D-dimerIn lower-risk patients, an Aortic Dissection Detection Risk Score of 0–1 with D-dimer < 500 ng/mL makes acute aortic syndrome very unlikely; an ADD-RS above 1 needs imaging even if D-dimer is negative.

Stanford type A or type B?

Commonly confused

Where	Involves the ascending aorta
Typical complications	Aortic regurgitation, tamponade, coronary occlusion
Definitive treatment	Emergency open surgical repair
Endovascular repair	Only when open surgery is not an option
In-hospital mortality (treated)	About 20%

Commonly confused

Tell apart

Inferior STEMI with new AR murmurChest pain with inferior ST elevation and a new aortic regurgitation murmur suggests a type A dissection into the right coronary artery; image the aorta first — suspected dissection is an absolute contraindication to fibrinolysis.

More detail

Reference

Show 6 reference facts

Up to 20% of patients present with syncope (pain, baroreceptor activation, cerebral vessel obstruction or tamponade); consider dissection in unexplained syncope, stroke or acute heart failure with chest or back pain.

About 20% die before reaching the hospital; treated in-hospital mortality is about 20% for type A and 10% for type B.

DeBakey classification: type I starts in the ascending aorta and extends at least to the arch, type II is confined to the ascending aorta, and type III starts beyond the left subclavian artery.

Intramural hematoma and penetrating aortic ulcer are acute aortic syndromes managed like dissection: prompt surgery for acute type A intramural hematoma, initial medical therapy for uncomplicated type B.

For long-term blood pressure control almost any combination works, but avoid pure vasodilators (hydralazine, minoxidil) and beta-blockers with intrinsic sympathomimetic activity (acebutolol, pindolol).

Late complications include redissection, aneurysm of the weakened aorta and progressive aortic regurgitation; repair can be complicated by stroke, paraplegia from spinal cord ischemia, renal failure and endoleak.

Pearl

Impulse control before anything else: rate down with a beta-blocker first, then pressure — a vasodilator alone whips the heart and tears the aorta further.

Sources · Merck Manual Professional — Aortic Dissection · ACC — 2022 ACC/AHA Aortic Disease Guideline Key Perspectives (Part 2 of 2) · Isselbacher EM et al. 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease. Circulation 2022;146:e334–e482 · A Narrative Review of Biomarkers and Imaging in the Diagnosis of Acute Aortic Syndrome. Diagnostics (Basel) 2025 (PMC11765216) · Rao SV et al. 2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes. Circulation 2025;151:e771–e862 · ACC — Review on Acute Aortic Dissection: Key Points (2023) · Merck Manual Professional — Table: Contraindications to Fibrinolytic Therapy for STEMI · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).