Week Five - Case Two

Question 1

what sort of pain is associated with aortic dissection

Answer 1

central pain radiating to the back. not affected by exertion, movement or position and is not pleuritic

Question 2

what the CXR findings for aortic dissection

Answer 2

mediastinal widening
widened aortic knob
trachea can be deviated also

Question 3

what are significant consequences of aortic dissection

Answer 3

MI and pericardial effusion with tamponade

Question 4

when can you only assess cardiomegaly on CXR

Answer 4

on a PA film

Question 5

what are the most common signs of aortic dissection

Answer 5

pulsus paradoxus
pulse deficits
distended neck veins
muffled heart sounds

Question 6

what is the definition of pulse deficits

Answer 6

a difference of 20mmHg or more in blood pressure between left and right arms

Question 7

what are the risk factors for aortic dissection

Answer 7

hypertension which is poorly controlled (70% of patients)

atherosclerosis (30%)

aortopathy such as bicuspid aortic valve disease (16%)

connective tissue disorders such as Marfan’s (5%)

Question 8

what should be arranged if an aortic dissection is suspected

Answer 8

an urgent contract thoracic aortogram should be arranged

Question 9

what is the mortality risk associated with aortic dissection

Answer 9

untreated it is very high - 50% within the first 48 hours.

Question 10

what is Type A aortic dissection

Answer 10

aortic dissection involving the ascending aorta

Question 11

what classification is used for aortic dissection

Answer 11

Stanford Classification

Question 12

what is Type B aortic dissection

Answer 12

aortic dissection not involving the ascending aorta

Question 13

what should be sought for a Type A

Answer 13

urgent cardiothoaric surgical advice should be sought for immediate surgery

Question 14

what should be sought for Type B

Answer 14

urgent vascular surgical referral should be made and patient should be admitted for BP control and monitoring in a cardiac care of high dependency unit

Question 15

what is recommended to reduce the risk

Answer 15

lifestyle modification is recommended to reduce the risk and includes smoking cessation

Question 16

what are the 5 steps in the pathophysiology of aortic dissection

Answer 16

1. patients usually have an underlying aortic pathology, predisposing to dissection
2. an intimal tear of the lining of the aortic causes sudden onset chest pain. this is called an aortic dissection
3. subsequently there is movement of blood through the tear between the intima and medial layers of the aorta. this gives rise to a true and false lumen
4. the false lumen enlarges and can occlude the true lumen potentially compromising the blood supply of organs distal to the original dissection tear. the original dissection can also extend. these can give rise to ongoing chest pain
5. type A dissection is a cardiothoracic surgical emergency. type B is a vascular surgery emergency

Question 17

what is the link between Marfan’s and aortic dissection

Answer 17

Aortic dissection / dilatiation – particularly at the aortic root. The arotic media is less resistant to stretching, particularly in areas of high pressure – hence the involvement of the aortic root. In severe cases, dissection can occur before the age of 10! Aortic regurg and endocarditis are also common

Question 18

what are the three layers of the aortic wall

Answer 18

intima, media, and adventitia

Question 19

what happens when there is constant exposure to high pulsatile pressure and shear stress

Answer 19

leads to a weakening of the aortic wall in susceptible patents resulting in an intimal tear

following this, blood flows into the intimal-media space, creating a false lumen

Question 20

where do most of the tears take place and why

Answer 20

most take place in the ascending aorta, usually in the right lateral wall where the greatest shear force on the aorta occurs

Question 21

what can ADD propagate

Answer 21

anterograde and/or retrograde and depending on the direction the dissection travels, cause branch obstruction that produces ischemia of affected territory

Question 22

what can proximal type A AADs instigate

Answer 22

acute tamponade, aortic regurgitation or aortic rupture

Question 23

what are both the true and false lumen lined with

Answer 23

in an ADD, the true lumen is lined by the intima whereas the false lumen is within the media

in most cases, the true lumen is smaller than the false lumen

Question 24

what are the three common sites for ADD

Answer 24

nearly 2-2.5cm above the aortic root

just distal to the origin of the left subclavian artery

in the aortic arch

Question 25

what are the there syndromes associated with an altered aortic wall

Answer 25

Ehlers-Danlos
Loeys-Dietz
Turner syndrome

Question 26

ADD is painless in which patients?

Answer 26

Marfan’s patients

Question 27

what is Horner syndrome - a presentation of ADD

Answer 27

Horner syndrome is a rare condition classically presenting with partial ptosis (drooping or falling of the upper eyelid), miosis (constricted pupil), and facial anhidrosis (absence of sweating) due to a disruption in the sympathetic nerve supply

Question 28

what are the X ray features that suggest ADD

Answer 28

Left apical cap
Pleural effusion
Deviation of the esophagus
Deviation of the trachea to the right
Depression of the left mainstem bronchus
Loss of the paratracheal stripe

Question 29

what is a 12 lead mandatory for

Answer 29

to rule out an MI

Question 30

what is the preferred analgesic

Answer 30

morphine as it decreases synthetic output swell

Question 31

what is given to reduce the heart and blood pressures

Answer 31

a short acting IV beta blocker aiming for a HR of 60bpm

Question 32

what else can be used for rate control

Answer 32

calcium channel blockers if contraindications for beta blockers

Question 33

why should beta blockers be used with caution in the settings of acute aorta regurgitation

Answer 33

because they block compensatory tachycardia