12 Aortic Dissection and Related Aortic Syndromes Flashcards
examples of acute aortic syndromes
aortic dissection
penetrating atherosclerotic ulcer
intramural hematoma
aortic aneurysmal leakage
ruptured abdominal aortic aneurysm
the most common cardiovascular complication of Marfan’s syndrome
aortic root disease and type A dissection (ascending aorta)
remarks on acute aortic syndromes
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
remarks on aortic dissection
aortic dissection occurs after a violation of the intima allows blood to ender the media and dissect between the intimal and adventitial layers
the 2 most common intimal tear sites in aortic dissection
- sinotubular juction at the start of the ascending aorta (50-65%)
- just beyond the left subclavian artery at the junction between the ascending and descending aorta (20-30%)
2 systems of classifying aortic dissections
- Standford classification
- DeBakey classification
Describe Standford classification
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
Describe DeBakey classification
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
remarks on aortic intramural hematoma
- it results from infarction of the aortic media, usually from injury to the vasa vasorum
- this often appears as a crescent on CT
- an intramural hematoma may resolve spontaneously or may lead to dissection
classic presentation of aortic dissection
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
dissection that may present as a classic stroke
dissection in or near a carotid artery
dissection that may lead to cardiac tamponade
a proximal dissection to the aortic root may lead to cardiac tamponade
and is generally fatal
remarks on blood pressure difference in aortic dissectio
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
Category 1 features of aortic dissection as per the Aortic Dissection Detection Risk Score (ADDRS)
“Underlying Condition”
Marfan’s syndrome
Family history of aortic disease
Aortic valvular disease
Recent aortic manipulation
Thoracic aortic aneurysm
Category 2 features of aortic dissection as per the Aortic Dissection Detection Risk Score (ADDRS)
Chest/back/abdominal Pain”
Abrupt onset
Severe in intesneity
Ripping or tearing
Category 3 features of aortic dissection as per the Aortic Dissection Detection Risk Score (ADDRS)
“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
remarks on aortic dissection and ACS
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
the marker most thoroughly investigated for aortic dissection
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
most common radiographic abnormality in aortic dissection
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
imaging modality of choice for diagnosis of dissection
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
this often appears as a crescent on CT
intramural hematomas
- often identified by a high-signal mass in the aorta
- often appears as a crescent
- best seen on noncontrasted images
On CT, these often have overhanging edges and focal outpouchings of the aorta itself
penetrating atherosclerotic ulcers
- CT diagnosis of penetrating atherosclerotic ulcer depends on extension of the ulcer past the intima
remarks on the “triple rule-out”
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
Management of aortic dissection
- Goal: SBP 100-120 mm Hg and HR <60 (2022: 60-80)
- 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 - Vasodilators may be added for further antihypertensive treatment after successful administration of esmolol or labetalol. (nicardipine, clevidipine, nitroglycerine, or nitroprusside)
How to administer esmolol in aortic dissection?
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
How to administer labetalol in aortic dissection
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)
Disposition in aortic dissection
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 ‼️
remarks on aortic dissection complicating pregnancy
aortic dissection in pregnancy is rare and usually occurs in the third trimester and postpartum period
