Clinical Perspective of Aortic Disease

Question 1

4 Main Pathological Processes leading to Disease of the Aorta

Answer 1

• Cystic Medial Degeneration
• Atherosclerosis
• Inflammatory Disorders
• Trauma

Question 2

Cystic Medial Degeneration

Answer 2

• Very Important predisposing factor to disease of aorta
• Can be genetically determined
• Most important in ascending aortic disease
• Characterized by:

*smooth muscle cell necrosis

*smooth muscle cell apoptosis

*degeneration of elastic fibers within the media

*cystic spaces develop

*extends to the elastic components of the adventitia

• Weakens the aortic wall
• Prone to aneurysm/dissection

Question 3

Genetic Diseases Predisposing to Cystic Medial Degeneration

Answer 3

• Marfan syndrome
• Ehlers-Danlos syndrome
• Loeys-Dietz syndrome
• Familial aoritc aneurysm and/or dissection syndromes
• Bicuspid aortic valve
• Autosomal dominant polycystic kidney disease
• Neurofibromatosis
• Turners syndrome

Question 4

Marfan Syndrome

Answer 4

• Mutation in fibrillin 1 gene (FBN1)
• Dilation and aneurysm of the aortic root, dilation of the pulmonary artery, and dilation or dissection of the descending throacic or abdominal aorta
• Autosomal dominant disorder of the connective tissue
• 2-3 in 10,000
• Also seen in musculoskeletal and ocular systems, much less frequent in pulmonary, nervous, and integumentary fibrils
• 80% morbidity linked to aortic aneurysm and dissection
• Ghent criteria, Z-scores, genetic testing

Question 5

Ehlers-Danlos Syndrome

Answer 5

• Mutations in COL5A1, COL5A2 and COL3A1 genes
• Arterial mid-sized rupture, specially involving thoracic or abdominal vessels. Frequently descending and abdominal aorta
• Autosomal dominant, recessive autosomal, or x-linked patterns
• Prevalence 1 in 10,000 depending on type
• Characterized by articular hypermobility, skin extensibility, tissue fragility
• Classification: 6 types

Question 6

Loeys-Dietz Syndrome

Answer 6

• Mutation in TGFBR1 and TGFBR2 genes
• Premature and aggressive aneurysms and dissections. Aneurysms distal to the aortic root
• Dominant autosomal
• No clinical diagnostic criteria
• Genetic testing is helpful
• Mean survival is 37yrs/first vascular procedure age 20

Question 7

Bicuspid Aortic Valve

Answer 7

• Most common congenital heart malformation, 1-2% in gen pop.
• Unknown aortic dilation typically involves the aortic root and ascending aorta whereas it is not present in the descending and abdominal aorta

Question 8

Autosomal Dominant Polycystic Kidney Disease

Answer 8

• Mutation in PKD1 and PKD2 genes

Question 9

Neurofibromatosis

Answer 9

• Aneurismal arterial disease affecting the renal arteries and abdominal aorta

Question 10

Turners Syndrome

Answer 10

• Dilation of the aortic root and dissection of the thoracic aorta

Question 11

Aortic Dissection Process

Answer 11

• Splitting of aortic wall in the media
• Formation of false lumen that courses along w/ true lumen
• Intimal tear starts the dissection, allows pulsatile high pressure flow into the media
• Also there can be primary rupture of the vaso vasorum and resultant intramural hematoma

Question 12

Aortic Dissection Classifications

Answer 12

• DeBakey
• Stanford

Question 13

Aortic Dissection Treatments

Answer 13

• Acute type A dissections are surgical emergencies

*very high mortality rates up to 1-2% per hr.

• Beta Blockade +/- sodium nitroprusside for both types
• Type B dissections are treated medically unless complications; assoc. w/ high mortality rates

Question 14

Intramural Hematoma

Answer 14

• Non-communicating blood collection in the aortic wall/media
• May be related to rupture of vaso vasorum
• Can communicate w/ adventitial space and lead to rupture or dissection w/ intimal tear
• If small, benign and resolve

Question 15

Penetrating Aortic Ulcer

Answer 15

• Develops when aortic atheromatous plaque erodes into the aortic media
• Disruption of internal elastic lamina -> extension into media
• Can form intramural hematoma, saccular aneurysm, pseudoaneurysm, or rupture
• Elderly, hypertensive (>90%) pts
• Depeding on location, observation and resolution

Question 16

Aortic Aneurysm

Answer 16

• Complications of aortic aneurysm are a leading cause of death in the US in the 55+ age
• 1/3 thoracic, 2/3 abdominal
• Asymptomatic, incidental finding
• Defined when dilation of aorta is 1.5 times the reference diameter
• Include all 3 layers of the aortic wall
• Changes in the collagen and elastin in the media as we age contribute to weakening of the wall structure and aneurysm formation
• Genetic disorders

Question 17

Aortic Aneurysm Locations

Answer 17

• Ascending aortic aneurysm- AV to innominate artery (60%)
• Aortic arch- involves brachiocephalic vessels (10%)
• Descending aortic aneurysms- distal to subclavian artery (40%)
• Thoracoabdominal aneurysm (10%)

*Crawford classification

Question 18

Crawford Aortic Aneurysm Classification Illustration

Answer 18

Question 19

Thoracic Aortic Aneurysm

Answer 19

• Often asymptomatic and found incidental or w/ CXR, TTE or CT scan
• Identify subgroups at risk for genetically assoc. syndromes
• Medical therapy to slow progression

*beta blockers and ACE-I have been shown to slow progression

Symptomatic

• Due to rapid expansion, compression, dissection, rupture
• Pain is most common symptom
• Hemodynamic compromise

Question 20

Aortic Aneurysm Indications for Surgery

Answer 20

• Size is risk factor for dissection and rupture
• Degenerative ascending TAA- 5.5cm
• Degenerative descending TAA- 6.0cm
• Genetic syndrome ascending TAA- 4.5-5.0cm
• Genetic Syndrome descending TAA- 5.5-6.0cm
• Rapid enlargement of aneurysm >0.5-1.0cm/year

Question 21

Abdominal Aortic Aneurysm

Answer 21

• Most common form of arterial aneurysm
• Risk factors include age, male, smoking, hypertension
• Familial predisposition- relatives may have up to 30% increased risk
• Symptoms- pain, sudden onset chest, back, flank pain
• 75% are infrarenal

*atherosclerotic process- most common in infrarenal AAA

*lack of vaso vasorum in infrarenal aorta