Aortic dissection

Question 1

Definition

Answer 1

separation has occurred in aortic wall intima, causing blood flow into a new false channel composed of the inner and outer layers of the media.

Question 2

Classification

Answer 2

Stanford

Type A: Dissection involves the ascending aorta with or without involvement of the arch and descending aorta. View image

Type B: Dissection does not involve the ascending aorta. Predominantly involves only the descending thoracic (distal to the left subclavian artery) and/or abdominal aorta. View image

DeBakey

Type 1: Tear originates in the ascending aorta and involves the ascending and arch aorta, and variable amounts of the descending thoracic aorta.

Type 2: Dissection is confined to the ascending aorta. View image

Type 3: Tear originates distal to the left subclavian artery and extends through the thoracic aorta (3A) or extends beyond the visceral segment (3B).

Question 3

Risk factors

Answer 3

Strong
HTN
atherosclerotic aneurysmal disease
Marfan's syndrome
Ehlers-Danlos syndrome
bicuspid aortic valve
annulo-aortic ectasia
coarctation
smoking
FHx of aortic aneurysm or dissection

Question 4

Diagnostic factors

Answer 4

Key diagnostic factors
features of Marfan's/Ehlers-Danlos syndromes (common)
acute severe chest pain (common)
interscapular pain (common)
left/right BP differential (common)
pulse differential/deficit (common)
diastolic murmur (common)->crescendo, aortic incompetence
syncope (uncommon)
hypotension (uncommon)

hypertension (common)
dyspnoea (uncommon)
altered mental status (uncommon)
paraplegia (uncommon)
hemiparesis/paraesthesia (uncommon)
abdominal pain (uncommon)
limb pain/pallor (uncommon)
left-sided decreased breath sounds/dullness (uncommon)

Question 5

Investigations

Answer 5

ECG
ST segment depression may occur with acute dissection, but ST elevation occurs rarely

CXR
may show widened mediastinum

cardiac enzymes
cardiac enzymes usually negative

CT scan
intimal flap

renal function tests
elevated creatinine and BUN

FBC
reduced or normal

type and cross
preparation for surgery

Question 6

Acute management

Answer 6

Call for help->CT surgeons
ABC, O2, IV access, Fluids, Investigations, Group and hold
Keep NBM
Morphine + metoclopramide
Metoprolol
Nitroprusside if beta blocker not sufficient

Open surgery or endovascular stenting