Diseases of the Thoracic Aorta Flashcards Preview

Cardiovascular System > Diseases of the Thoracic Aorta > Flashcards

Flashcards in Diseases of the Thoracic Aorta Deck (37):
1

Features of Tunica Intima

- Layer of endothelial cells
- Subendothelial layer: collagen and elastic fibres
- Separated from tunica media internal elastic membrane

2

Features of Tunica media

- Smooth muscle cells
- Secrete elastin in the form of sheets, or lamellae

3

Features of Tunica adventitia

- Thin connective tissue layer
- Collagen fibres and elastic fibres (not lamellae)
- The collagen in the adventitia prevents elastic arteries from stretching beyond their physiological limits during systole

4

What are risk factors of atherosclerosis?

- Hypertension
- Hypercholesterolaemia
- Smoking
- Diabetes
- Family history
- Male > Female (relative protection in females until menopause)

5

Atherosclerosis timeline

Foam cells > Fatty streak > Intermediate lesion > Atheroma > Fibrous plaque > Complicated lesion/Rupture

6

What can atherosclerosis lead to?

- Stroke
- Myocardial infarction
- Aneurysm

7

What is an Aneurysm?

A localised enlargement of an artery caused by a weakening of the vessel wall

8

Classification of aneurysms by type

- Saccular aneurysm
- Fusiform aneurysm
- False aneurysm
- Dissecting aneurysm

Saccular and Fusiform are true aneurysms

9

What are features of a True aneurysm?

- Weakness & dilation of wall
- Involves all 3 layers

10

What are true aneurysms associated with?

- Hypertension
- Atherosclerosis
- Smoking
- Collagen abnormalities (Marfans's, cystic medial necrosis)
- Trauma
- Infection (mycotic/syphillis)

11

What is a False Aneurysm?

Rupture of wall of aorta with the haemotoma either contained by the thin adventitial layer or by the surrounding soft tissue

12

What does a False aneurysm cause?

- Inflammation (e.g. endocarditis with septic emboli)
- Trauma
- Iatrogenic
- Thrills
- Bruit
- Pulsatile mass
- Ischaemia
- Rupture

13

Classification of aortic aneurysm by site

- Normal
- Ascending aorta aneurysm
- Aortic arch aneurysm
- Descending aorta aneurysm
- Abdominal aorta aneurysm

14

Signs and symptoms of Thoracic aneurysms

Asymptomatic

Based on the location of the aneurysm:
- Shortness of breath or even heart failure (AR)
- Dysphagia and hoarseness (ascending aorta, chronic)
- Sharp chest pain radiating to back - between shoulder blades, possible dissection
- Pulsatile mass
- Hypotension

15

Features of aortic dissection

- Tear in the inner wall of aorta
- Blood forces walls apart
- Acute - medical/surgical emergency
- Chronic

16

Classification systems of thoracic aortic dissection

DeBakey
- Type I
- Type II
- Type III

Stanford
- Type A: all dissections involving the ascending aorta, regardless of the site of origin.
- Type B: All dissections not involving the ascending aorta.

17

Features of Dissection

- False lumen can progress in an antegrade or retrograde direction
- May occlude branches (e.g. mesenteric, carotid, renal, spinal)
- Rupture: back into the lumen or externally in to pericardium (tamponade) or mediastinum
- Dilation of ascending aorta may cause acute aortic regurgutation.

18

Aetiological factors of dissection

- Hypertension
- Atherosclerosis
- Trauma
- Marfan's syndrome

19

Histology of dissection

Cystic medial necrosis

20

Symptoms of aortic dissection

- Tearing, severe chest pain (radiating to back)
- Collapse (tamponade, acute AR, external rupture)
- Beware inferior ST elevation

21

Examination signs of aortic dissection

- Reduced or absent peripheral pulses (BP mismatch between sides)
- Hypotension/hypertension
- Soft early diastolic mumur (AR)
- Pulmonary oedema
- Chest X-ray usually shows a widened mediastinum
- Diagnosis can be confirmed by echocardiogram or CT scanning

22

What is the treatment for Type A aortic dissection?

Surgery: prophylactic aortic root surgery

23

What is the treatment for Type B aortic dissection?

- Meticulous blood pressure control
- Sodium nitroprusside plus beta blocker

24

Infection and Inflammation affecting the aorta

Infection: Syphyllis

Inflammation: Takayasu's Arteritis

25

Features of Takayasu's Arteritis

- Granulomatous vasculitis
- Females > Males
- Aorta & main branches
- Stenosis, thrombosis, aneurysms, renal artery stenosis, neurological sx
- Steroids
- Surgery

26

Features of Syphilis

- STD
- Treponema pallidum
- Antibiotics prevent late stages

27

Signs of Primary and Secondary syphillis

Primary - Chancre

Secondary - Rashes (mainly back rashes)

28

Tertiary Syphilis without treatment

- Late neuro-syphillis
- Gummatous syphillis
- Cardiac syphillis

29

Features of congenital aortic aneurysm

- Bicuspid aortic valve
- Marfan's syndrome
- Coarctation

30

Features of Bicuspid aortic valve

- Most common congenital abnormality
- 1-2% prevalence
- Prone to stenosis +/- regurgitation
- Associated with coarctation
- Abnormal aorta (reduced tensile strength)
- Prone to aneurysm/dissection
- Monitor with echo/MRI

31

What occurs during Aortic Coarctation?

Narrowing below the left subclavian artery

32

What are the 3 shunts in coarctation?

- Ductus arteriosus
- Foramen ovale
- Ductus venosus

33

Features of Coarctation

- Aortic narrowing close to where Ductus arteriosus inserts (ligamentum arteriosum)

3 Types:
- Pre-ductal: (5% turner's) can be life-threatening if severe narrowing
- Ductal
- Post-ductal: most common in adults, hypertension in upper extremities, weak pulses in lower limbs

34

Signs of Coarctation

- Cold legs
- Poor leg pulses
- If before left subclavian artery: Radial, Radial and Right radial-femoral delay
- If after left subclavian artery: no radial-radial delay, right and left radio-femoral delay

35

Symptoms of coarctation

Infancy (severe)
- Heart failure
- Failure to thrive

Later life
- Hypertension

36

Imaging for coarctation

- Chest Xray
- CMRI: narrowing distal to the subclvian artery

37

Features of Marfan's Syndrome

- Fibrillin 1 gene
- Connective tissue weakness
- Aortic/Mitral valve prolapse - regurgitation
- Skeletal system
- Eyes (cataract, lens dislocation)
- Vascular: aneurysm, dissection
- Lungs (pneumothorax)
- Aneurysm
- Dissection