12 Aortic Dissection and Related Aortic Syndromes

Question 1

examples of acute aortic syndromes

Answer 1

aortic dissection
penetrating atherosclerotic ulcer
intramural hematoma
aortic aneurysmal leakage
ruptured abdominal aortic aneurysm

Question 2

the most common cardiovascular complication of Marfan’s syndrome

Answer 2

aortic root disease and type A dissection (ascending aorta)

Question 3

remarks on acute aortic syndromes

Answer 3

acute aortic syndromes occur in the setting of chronic hypertension and other factors that lead to degeneration of the media of the aortic wall

chronic cocaine or amphetamine use accelerates atherosclerosis and increase the risk for dissection

Question 4

remarks on aortic dissection

Answer 4

aortic dissection occurs after a violation of the intima allows blood to ender the media and dissect between the intimal and adventitial layers

Question 5

the 2 most common intimal tear sites in aortic dissection

Answer 5

1. sinotubular juction at the start of the ascending aorta (50-65%)
2. just beyond the left subclavian artery at the junction between the ascending and descending aorta (20-30%)

Question 6

2 systems of classifying aortic dissections

Answer 6

1. Standford classification
2. DeBakey classification

Question 7

Describe Standford classification

Answer 7

Type A: any involvement of the ascending aorta
- more commonly presents with anterior chest pain

Type B: restricted to only the descending aorta
- more commonly presents with abdominal pain

Question 8

Describe DeBakey classification

Answer 8

Type 1: simultaneously involves the ascending aorta, the arch, and the descending aorta
Type 2: involves only the ascending aorta
Type 3: involves only the descending aorta

Question 9

remarks on aortic intramural hematoma

Answer 9

1. it results from infarction of the aortic media, usually from injury to the vasa vasorum
2. this often appears as a crescent on CT
3. an intramural hematoma may resolve spontaneously or may lead to dissection

Question 10

classic presentation of aortic dissection

Answer 10

abrupt and severe pain in the chest that radiates to an area between the scapulae and may be accompanied by a feeling of impending doom

Question 11

dissection that may present as a classic stroke

Answer 11

dissection in or near a carotid artery

Question 12

dissection that may lead to cardiac tamponade

Answer 12

a proximal dissection to the aortic root may lead to cardiac tamponade
and is generally fatal

Question 13

remarks on blood pressure difference in aortic dissectio

Answer 13

a blood pressure difference >20 mm Hg between arms is independently associated with aortic dissection
however, 19% of ED patients without dissection also have this clinical finding

Question 14

Category 1 features of aortic dissection as per the Aortic Dissection Detection Risk Score (ADDRS)

Answer 14

“Underlying Condition”
Marfan’s syndrome
Family history of aortic disease
Aortic valvular disease
Recent aortic manipulation
Thoracic aortic aneurysm

Question 15

Category 2 features of aortic dissection as per the Aortic Dissection Detection Risk Score (ADDRS)

Answer 15

Chest/back/abdominal Pain”
Abrupt onset
Severe in intesneity
Ripping or tearing

Question 16

Category 3 features of aortic dissection as per the Aortic Dissection Detection Risk Score (ADDRS)

Answer 16

“Abnormal Physical Examination”
1. Pulse amplitude difference or systolic BP differential in extremities
2. Focal neurologic deficit and chest, back, or abdominal pain
3. New murmur of aortic insufficiency and chest, back, or abdominal pain
4. Shock or hypotension

Question 17

remarks on aortic dissection and ACS

Answer 17

It may be difficult to differentiate aortic dissection from ACS on ECG, because both condition are associated with ECG changes and dissection may limit or obstruct coronary artery blood flow

Question 18

the marker most thoroughly investigated for aortic dissection

Answer 18

D-Dimer
- a metaanalysis found a
98% sensitivity and negative likelihood ratio of 0.05 using a D-dimer cut point of 500 ng/mL
- specificity was low at 41%
- Guidelines do not endorse the use of D-dimer as the sole means of excluding aortic dissection, and several authors have cautioned against this practice
- the false-negative rate using D-dimer is as high as 18%

One study found that ADDRS of 0 or 1 plus negative D-dimer (<500 ng/mL) had a low rate of aortic dissection (0.3%) (the study needs to be externally validated

Question 19

most common radiographic abnormality in aortic dissection

Answer 19

widened mediastinum or abnormal aortic contour

other possible findings:
- pleural effusion
- displacement of aortic intimal calcification
- deviation of the trachea, mainstem bronchi, or esophagus
12-37% of patients have no abnormality, and this study should not be used to exclude dissection

Question 20

imaging modality of choice for diagnosis of dissection

Answer 20

CT, with and without IV contrast
- can reliably identify a false lumen
- can provide additional details such as:
— anatomy of the dissection
— location of the dissection flap
— extension of the flap into great vessels
— signs of aortic rupture
– signs of end-organ damage

Question 21

this often appears as a crescent on CT

Answer 21

intramural hematomas
- often identified by a high-signal mass in the aorta
- often appears as a crescent
- best seen on noncontrasted images

Question 22

On CT, these often have overhanging edges and focal outpouchings of the aorta itself

Answer 22

penetrating atherosclerotic ulcers
- CT diagnosis of penetrating atherosclerotic ulcer depends on extension of the ulcer past the intima

Question 23

remarks on the “triple rule-out”

Answer 23

Coronary/pulmonary/aortic CT angiography
- used to differentiate acute coronary artery disease, pulmonary embolism, and acute aortic dissection
- has not been shown to improve diagnostic yield, reduce clinical events, or diminish downstream resource use
- therefore, in its current form, it cannot be recommended

Question 24

Management of aortic dissection

Answer 24

1. Goal: SBP 100-120 mm Hg and HR <60 (2022: 60-80)
2. Initial treatment should be a negative inotropic agent in order to lower BP without increasing the shear force on the intimal flap of the aorta
   - B-blockade is ideal (short-acting are preferred, such as esmolol, labetalol)
   - B-blockers are associated with improved survivial
3. Vasodilators may be added for further antihypertensive treatment after successful administration of esmolol or labetalol. (nicardipine, clevidipine, nitroglycerine, or nitroprusside)

Question 25

How to administer esmolol in aortic dissection?

Answer 25

ESMOLOL
Initial bolus of 0.1 to 0.5 mg/kg IV over 1 minute
followed by infusion of 0.025 to 0.2 mg/kg/min

Question 26

How to administer labetalol in aortic dissection

Answer 26

LABETALOL
initial dose of 10-20 mg IV
with repeat doses of 20-40 mg every 10 minutes
max dose of 300 mg
(Labetalol is a B-blocker with limited a-blocking characteristics in a 7:1 ratio)

Question 27

Disposition in aortic dissection

Answer 27

Rapid referral to a vascular surgeon is mandatory
- Emergency open repair remains the treatment of choice for most patients; however endovascular repair is being used more frequently

Patients with acute aortic syndromes are likely to require admission to an ICU for hemodynamic therapy and careful monitoring.
- clearly, no patient with an acute aortic syndrome should be discharged without specialty consultation ‼️

Question 28

remarks on aortic dissection complicating pregnancy

Answer 28

aortic dissection in pregnancy is rare and usually occurs in the third trimester and postpartum period