Acute Aortic Dissection

Question 1

Aetiology and pathophysiology of AAD

Answer 1

-Represents a tear in inner (intima) and middle layers of aorta so blood into media (mechanical components)= false lumen, can propagate different vessels
-Occurs when force on aortic wall exceeds strength

-Aortic wall weakness
=Marfan/ connective tissue disorder
=Aneurysm (family history)
-Abnormal haemodynamics
=Hypertension
=Bicuspid aortic valve (one sided aneurysm)

Question 2

Prevalence of AAD

Answer 2

-35 in 100,00
=30-40s connective tissue disorder
=60-70s degenerative
-Can occur anywhere in thoracic aorta

Question 3

Symptoms of AAD

Answer 3

-Sudden onset severe chest pain (90%) radiating to back (64%) or abdomen (43%)

-Other symptoms depend on dissection location
=Type A (ascending, most commonly above the sino-tubular junction above the root, can affect coronary arteries): syncope, focal neurological symptoms
=Type B (descending): flank/ abdominal pain

Question 4

AAD clinical findings based on artery/ structure involved

Answer 4

-Aortic insufficiency or HF= aortic valve
-MI= coronary artery (often right)
-Cardiac tamponade= pericardium
-Haemothorax= thorax
-Horner syndrome= superior cervical sympathetic ganglion
-Stroke/ syncope= brachiocephalic, common carotid or left subclavian arteries
-Upper extremity pulselessness, hypotension pain= subclavian artery
-Paraplegia= intercostal arteries
-Back or flank pain, renal failure= renal artery
-Abdominal pain, mesenteric ischaemia= celiac or mesenteric arteries
-Lower extremity pain, pulselessness, weakness= common iliac artery

Question 5

AAD investigations

Answer 5

-ECG= helpful in excluding STEMI
-CXR= wide mediastinum
-D-Dimer= useful for excluding dissection (low= unlikely)
-Definitive imaging= CT angiography of aorta

Question 6

AAD treatment

Answer 6

-Type A= emergency urgent surgery, blood pressure control
-Type B= with high-risk factor: endovascular or open repair, IV beta blockers/ stable: conservative management

Question 7

Prognosis Type A AAD

Answer 7

-91% alive at 3 years if they made it to repair
-37-50% who did not receive surgery did not survive to discharge
-Longer term survival less good (5 year 68%)

Question 8

Prognosis Type B AAD

Answer 8

-Medical therapy- 10% in hospital mortality, 78% at 3 years
-Open surgery- 32% in hospital mortality, 83% at 3 years
-EVAR- 7% in hospital mortality, 76% at 3 years