Aortic Dissection

Question 1

What is an aortic dissection?

Answer 1

A tear in the tunica intima of the aortic wall.

This leads to blood flowing between the tunica intima and media splitting them apart

Question 2

What is acute AD?

Answer 2

Diagnosed within 14 days

Question 3

What is chronic AD?

Answer 3

Diagnosed after 14 days

Question 4

Who gets ADs?

Answer 4

More common in men

Connective tissue disorders

Peak onset between 50-70 years

Question 5

AD can progress anatomically either backwards or forwards.

Explain

Answer 5

The initial intimal tear can progress proximally or distally or in both directions.

Anterograde dissections propagate towards the iliac arteries

Retrograde dissections propagate towards the aortic valve at the root of the aorta. This can also cause prolapse of aortic valve, bleeding into pericardium and cardiac tamponade.

Question 6

Two systems classifying AD

Answer 6

Stanford Classification

DeBakey Classification

Question 7

Explain Stanford classification

Answer 7

Group A - Involves the ascending aorta and can propagate to the aortic arch and the descending aorta.

Group B - Dissections do not involve the ascending aorta and include DeBakey Type III

Question 8

Explain DeBakey Classification

Answer 8

Type I - Originiates in the ascending aorta and propagates at least to the aortic arch

Type II - Confined to the ascending aorta (classically in elderly patients with atherosclerotic disease and HTN)

Type III - Originates distal to the subclavian artery in the descending aorta

Question 9

Risk factors

Answer 9

HTN

Atherosclerosis

Male

Marfan’s and EDS

Bicuspid aortic valve

Question 10

Clinical features

Answer 10

Tearing chest pain radiating to the back

Tachycardia

Hypotension

New aortic regurgitation murmur

SIgns of end-organ hypoperfusion like reduced urine output, paraplegia, lower limb ischaemia, abdo pain.

Question 11

Dx

Answer 11

MI

PE

Pericarditis

MSK back pain

Question 12

Investigations

Answer 12

Routine bloods like FBC, U&Es, LFTs, troponin, coagulation

Crossmatch of at least 4 units

ABG

ECG should also be done

Question 13

Imaging

Answer 13

CT angiogram is first line imaging for diagnosis

This allows for classification, establish anatomy of dissection and planning.

Transoesophageal ECHO can also be done but is user dependent

Question 14

Initial management

Answer 14

High flow O2 + IV access 2x large bore cannulae

Fluid resus should be done cautiously and kept under 110mmHg systolic

Question 15

General idea of management of Type A vs Type B stanford dissections

Answer 15

Type A = Managed surgically as it involves ascending aorta

Uncomplicated Type B = Managed medically

Question 16

Post initial management therapy

Answer 16

Antihypertensive therapy lifelong

Surveillance imaging 1, 3 and 12 months post-discharge

Further scans at 6-12 months intervals depending on size of aorta

Question 17

Type A dissections management

Answer 17

Transfer to a cardiothoracic centre + surgery

Removal of the ascending aorta with or without the arch and replace with a synthetic graft

If dissection damaged the suspensory apparatus of the aortic valve this also needs repair.

Additional branches of the aortic arch require reimplantation into the graft.

Long type A that involve descending and possible even AA require staged procedures.

Question 18

Management of Type B dissections

Answer 18

Managed medically

First line = Management of hypertension with IV labetalol or CCB 2nd line.

Rapidly lower the systolic pressure, pulse pressure and pulse rate to minimise stress.

Question 19

Why are type B dissections not treated surgically?

Answer 19

Due to the risk of retrograde dissection

Question 20

When is surgical intervention indicated in Type B dissection?

Answer 20

Complicated disease

Rupture

Renal involvement

Visceral or limb ischaemia

Uncontrollable hypertension

Refractory to medical management

Question 21

Complications

Answer 21

Type B dissections can go on to be chronic and form an aneurysm, even if a stent is placed.

Aortic rupture

Aortic regurgitation

MI

Cardiac tamponade

Stroke or paraplegia

Death (20%)