Aortic dissection Flashcards
Definition
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.
Classification
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).
Risk factors
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
Diagnostic factors
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)
Investigations
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
Acute management
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