Disease of the Aorta

Question 1

Why is the aorta prone to injury and disease?

Answer 1

due to it’s constant exposure to high pulsatile pressure and shear stress

Question 2

What are the 3 layers of the aorta?

Answer 2

1. Intima- the thin inner layer
   
   2. Media- the thick middle layer that gives the aorta strength, elasticity and distensibility
   3. Adventitia- the thin outer layer

Question 3

What are the two anatomical divisions of the aorta?

Answer 3

1. The thoracic aorta- within the thoracic cavity.

2. The Abdominal aorta- the section below the diaphragm.

Question 4

what are the 3 distinct segments of the thoracic aorta?

Answer 4

ascending aorta
aortic arch
descending aorta

Question 5

what are the two distinct segments of the ascending aorta?

Answer 5

aortic root

ascending aorta

Question 6

Ascending aorta begins where?

what else is found here?

Answer 6

Begins at the level of the aortic valve

• Supports the aortic valve leaflets
• Extends into the sinotubular junction
• Area where right and left main coronaries arise

Question 7

Where does the descending thoracic travel too?

Answer 7

runs distally to the diaphragm

Question 8

What is the aortic isthmus and why is it important?

Answer 8

The point at which the aortic arch joins the descending aorta
This is the point at which the aorta is vulnerable to trauma due to its fixation to other structures within the chest cavity

Question 9

Where does the Abdominal aorta start and what are their 2 segments

Answer 9

Extends from the thoracic aorta at the level of the diaphragm to the bifurcation of the right and left common iliac arteries
Consists of two segments:
Suprarenal- the segment above the renal arteries
Infrarenal- the segment below the renal arteries

Question 10

What happens to the aorta as we age?

Answer 10

Elasticity and distensibility decreases with age
These changes occur earlier and more rapidly in men than in women
Loss of elasticity is accelerated in patients with HTN, Hypercholesterolemia and coronary artery disease

Question 11

what is the definition of aortic aneurysms?

Answer 11

Pathologic dilation of the aorta that can occur anywhere along the course of the aorta

Question 12

What are the two types of aneurysms?

Answer 12

Fusiform

Saccular

Question 13

what is the definition of a sccular aneurysm?

Answer 13

involves only a portion of the circumference (outpouching of a vessel)

Question 14

what is the definition of a fusiform aneurysm?

Answer 14

Fusiform- affects the entire circumference of a segment of a vessel

Question 15

how are aneurysms classified?

Answer 15

by location
Abdominal- below diaphragm
Thoracic- above diaphragm
Thoracolumbar- involves the descending thoracic aorta and abdominal aorta

Question 16

what are the complications with aneurysms?

Answer 16

dissection

acute rupture

Question 17

what is the average growth of thoracic aneurysms?

Answer 17

0.1-0.2cm/year

Those with marfans syndrome expand at a greater rate

Question 18

The risk of aneurysm is related to what?

Answer 18

size and presence of symptoms

Question 19

what is the most common cause of ascending aortic aneurysms?

Answer 19

Cystic medial necrosis is most common cause

Question 20

What is the most common cause of aortic arch and descending thoracic aneurysms?

Answer 20

Aortic arch and descending thoracic aneurysms

Atherosclerosis is the most common cause

Question 21

what are the risk factors for thoracic aneurysms?

Answer 21

Atherosclerosis
Connective tissue disorders such as Marfan’s and Ehlers-Danlos syndrome
Hypertension
Familial thoracic aortic aneurysm syndromes
Infections: Syphilis (rare), tuberculosis
Vasculitis (ex. Takayasu’s arteritis, giant cell arteritis)
Trauma (penetrating or non-penetrating)

Question 22

What are the signs and symptoms of thoracic aortic aneurysms

Answer 22

most are asymptomatic and found on routine physical exam or chest X-ray
If symptoms are present they coincide with the size and loctation of aneurysms
Aortic root: CHF, aortic regurgitation
Aortic arch: may compress the trachea (deviation, cough) or hoarness
Descending aortic: dysphagia
chest and back pain which is steady and deep

Question 23

Thoracic aortic aneurysms imaging diagnosis

Answer 23

Imaging/Diagnosis:
-CT scan: Modality of choice
-CXR:
Widening of mediastinum, displacement or compression of the trachea, calcifications of the outline of the aorta, large aortic knob
-Transesophageal echocardiogram (TEE):
can assess the proximal ascending aorta and descending thoracic aorta

MRI and Aortography
Both sensitive and specific test

Question 24

what is the Tx for aortic aneurysms?

Answer 24

Surgery
Aortic arch/ascending aorta: open surgery required
Descending: endovascular stent grafting
Medical Management

Question 25

``` what are the surgery indications for: thoracic Ascending aortic aneurysms? thoracic Descending aortic aneurysms? Aneurysms that have increased? Marfan’s syndrome patients and patients with bicuspid aortic valve: ```

Answer 25

Symptomatic patients Ascending aortic aneurysms >5.5-6.0cm Descending aortic aneurysms >6.5-7.0cm Aneurysms that have increased >1.0cm/year Marfan’s syndrome patients and patients with bicuspid aortic valve: ascending aortic aneurysm >5.0cm

Question 26

what are surgical complications with thoracic aortic aneurysms?

Answer 26

Higher morbidity and mortality than AAA Paraplegia (4-10% rate following endovascular repair) Stroke

Question 27

what are the medical management options for thoracic aneurysms?

Answer 27

Indications: Asymptomatic patients with aneurysms too small to justify surgery Beta Blockers: decrease mortality and slow the rate of dilation ACE-I/ARB’s: Studies are showing these reduce the rate of expansion in patients with Marfan’s syndrome

Question 28

what is the prognosis for thoracic aneurysms?

Answer 28

Survival rate of those not undergoing repair is 20% at 5 years Less than ½ of the patients with an acute rupture arrive to the hospital alive

Question 29

what is the definition of a AAA

Answer 29

Defined as an aneurysm measuring ≥3.0cm

Question 30

who is most at risk of AAA

Answer 30

Male to female ratio is 4:1

Question 31

AAA are commonly caused by?

Answer 31

90% of AAA >4.0cm are related to atherosclerosis

Question 32

where are most AAA located?

Answer 32

90% are infrarenal in location

Question 33

what is the risk of rupture for AAA

Answer 33

5.0cm: 5 year risk if 20-40%

Question 34

what is the mortality rate if AAA rupture

Answer 34

80% Approximately 60% of patients with acute rupture die before receiving medical attention Operative mortality for those reaching hospital is 50%

Question 35

AAA risk factors

Answer 35

``` Atherosclerosis- most common HTN Smoking Hypercholesterolemia Peripheral vascular disease Age (incidence increases rapidly at 55 yr in men and 70 yr in women) Male gender Genetics (1st degree relatives) ```

Question 36

AAA signs and symptoms?

Answer 36

mostly asymptomatic usually detected on exam as a palpable, pulsatile, non-tender mass or seen incidentally on imaging studies ordered for an unrelated symptoms As aneurysms expands, patients may feel abdominal or lower back pain pain is usually sign of impending rupture

Question 37

what is the gold standard for AAA diagnosis

Answer 37

abdominal ultrasound

Question 38

AAA diagnosis/imaging

Answer 38

Pulsatile mass noted from the xiphoid process to the umbilicus - X-ray- may show the calcified outline of the aneurysm (25% are not calcified) - Computed Tomography-Can diagnose and size aneurysm, though w/ contrast it is more expensive and a risk of allergic reaction - Contrast Aortography- Invasive and requires contrast - MR angiography-uses contrast, extremely accurate, used to plan for surgical repair.

Question 39

AAA treatment

Answer 39

Surgery | The definitive treatment!

Question 40

AAA medical management

Answer 40

Smoking Cessation Aggressive control of HTN and hyperlipidemia Beta blockers: reduce expansion and rupture Serial imaging q6months to monitor size and rate of expansion for aneurysms >4.0cm or greater

Question 41

AAA prognosis

Answer 41

``` If treated surgically 5 year survival after tx: 60% MI is leading cause of death If no surgery 12% annual risk of rupture if >6.0cm 25% annual risk of rupture if >7.0cm ```

Question 42

AAA prevention/screening

Answer 42

Treat risk factors (HTN, hyperlipidemia) Smoking Cessation Screening indications: All men age 65-75 years who have ever smoked Siblings or offspring of people w/ thoracic aortic or peripheral arterial aneurysms

Question 43

aortic dissection definition

Answer 43

Tear of the intima that results in the formation of a false channel w/in the media layer

Question 44

what are the common sites of aortic dissection

Answer 44

Right lateral wall of the ascending aorta (shear stress is highest) Descending thoracic aorta just below the ligamentum arteriosum

Question 45

When are aortic dissections most common and in who?

Answer 45

Peak incidence in the 6th and 7th decades of life | Men are at twice the risk as women

Question 46

Aortic Dissection RF

Answer 46

HTN (present in 70% of pts w/ dissection) Age (50-60’s) Bicuspid aortic valve Marfan’s syndrome and Ehlers Danlos syndrome Inflammatory aortitis (Takayasu’s arteritis, giant cell arteritis) Pregnancy (normal women in 3rd trimester 1/2 of all aortic dissections in females occur in women <40 years of age) Blunt trauma to aorta

Question 47

what is the debakey classification type I type II type III

Answer 47

Type I- Originates in ascending aorta, continues to the aortic arch and many times beyond the arch distally Type II- Originates and is confined to the ascending aorta Type III- Originates in the descending aorta with extension distally

Question 48

Stanford Classification: type A type B

Answer 48

Type A- all dissections involving the ascending aorta | Type B- all dissections not involving the ascending aorta

Question 49

aortic dissection symptoms

Answer 49

Severe pain most common initial symptom Pain described as “tearing”, “ripping” and “sharp” May be localized to the front or back of chest, lower back Migrates as it progresses Ascending dissection: neck, throat, jaw pain Descending dissection: interscapular pain Less common symptoms: Dyspnea, syncope, weakness, CHF, CVA, paraplegia, cardiac arrest

Question 50

aortic dissection signs

Answer 50

``` Hypertension or Hypotension Aortic regurgitation murmur Asymmetric or loss of pulses Pulmonary edema Neuro findings d/t carotid artery obstruction (hemiplegia, hemianesthesia) Paraplegia (spinal cord ischemia) ```

Question 51

aortic dissection imaging/diagnosis

Answer 51

CT, echocardiogram and MRI are diagnostic CXR: may show widened mediastinum and pulmonary edema EKG: will be normal

Question 52

What is the medical therapy for aortic dissection?

Answer 52

Medical therapy: Blood pressure control is essential Beta blocker unless contraindicated to get HR down to 60bpm Sodium nitruprusside to lower SBP <120 mmHg CCC if BB and nitroprusside is contraindicated Pain management (morphine) Used alone for uncomplicated and stable distal dissections w/ follow up imaging q 6-12 months

Question 53

what are surgical Tx for aortic dissection?

Answer 53

Superior to medical tx in acute proximal dissections Involves incising the intimal flap, obliterating the false lumen and placing a graft

Question 54

what are the indications for surgery for aortic dissection

Answer 54

Indications: Acute distal dissections w/ vital organ compromise, rupture or impending rupture Dissections in Marfan’s syndrome or Continued pain

Question 55

what are the indications for AAA surgery

Answer 55

Indications Any size that is symptomatic Any aneurysm that is rapidly expanding (≥ 0.5cm/yr) Diameter >5.5cm

Question 56

what are the surgical procedures done to fix a AAA?

Answer 56

``` Procedures Insertion of a prosthetic graft (open procedure) Mortality rate 1-5% Endovascular stent graft Mortality rate 0.5-2% ```