Aorta + PAD Lectures Flashcards
How does aortic diameter normally vary between ascending, descending thoracic, and abdominal?
- Ascending 3 cm
- Descending thoracic 2.5 cm
- Abdominal 1.8 to 2.0 cm
Why is the aorta prone to injury and disease?
Constant exposure to high pulsatile pressure and shear stress
Which vessel is more prone to rupture than any other?
Aorta
How is the wall of the aorta divided?
- Intima (thin inner layer)
- Media (thick middle; gives aorta strength, elasticity and distensibility)
- Adventitia (thin outer)
What is the aortic root and its purpose?
- Lower segment of ascending aorta
- Supports valve leaflets
- Extends into sinotubular junction (area where R/L coronaries arise)
What is the sinotubular junction?
Area where right and left main coronaries arise
What is the aortic isthmus?
- Point where aortic arch joins descending aorta
- Vulnerable to trauma
Which features of the aorta decrease with age?
- Elasticity
- Distensibility
Loss of aortic elasticity is accelerated in patients with:
- HTN
- Hypercholesterolemia
- CAD
Diseases of the aorta are:
- Aneurysms
2. Dissections
Define aortic aneurysm
- Pathologic dilation anywhere along the course of the aorta
- Involves ALL layers
2 types of aortic aneurysm
- Fusiform (entire circumference of a segment affected)
2. Saccular (outpouching, only involves a portion of circumference)
What are the complications of aortic aneurysms?
- Dissection
- Acute rupture (greatest fear)
What is the MC common etiology of ascending aortic aneurysms?
Cystic medial necrosis
What is the MC common etiology of aortic arch and descending thoracic aneurysms?
Athero
Risk factors for thoracic aortic aneurysms
- Athero
- CT disorders like Marfan’s
- HTN
- Familial
- Infections (syphilis, TB)
- Vasculitis
- Trauma
What is the diagnostic test of choice for thoracic aortic aneurysms?
CT
What is the treatment for thoracic aortic aneurysms (ascending, descending)?
- Arch/ascending = open surgery
- Descending = endovascular stent grafting
What are the indications for surgical repair of thoracic aortic aneurysms?
- Symptomatic
- Ascending 5.5-6.0+ cm
- Descending 6.5-7.0+ cm
- Grown 1.0+ cm in a year
- Marfan’s ascending 5.0+ cm
What are the surgical complications of thoracic aortic aneurysms?
- Higher morbidity and mortality than AAA
- Paraplegia
- Stroke
How do beta blockers help with thoracic aortic aneurysms?
Decrease mortality and slow the rate of dilation
What is the role of medical management in thoracic aortic aneurysms?
Used in asymp pts with aneurysms too small to justify surgery
How are ACE-I/ARBs used in thoracic aortic aneurysms?
May reduce rate of expansion in Marfan’s patients
Describe abdominal aortic aneurysm (AAA)
- 3.0+ cm
- Males 4:1
- 90% related to athero
- 90% are infrarenal
- Risk of rupture increases as size increases
What is the biggest risk factor for AAA?
Athero
What is the gold standard for diagnosing AAA?
Abdominal U/S
What is the definitive treatment of AAA?
Surgery
What are the indications for surgery in AAA?
- Any size that is symptomatic
- Rapidly expanding aneurysm (0.5+ cm/year)
- Diameter 5.5+ cm
What is the medical management of AAA?
- BBs reduce expansion and rupture
- Serial imaging q6 months
- Smoking cessation
- Aggressive control of HTN and HLD
When is screening for AAA recommended?
- All men 65-75 yo who have ever smoked
- Siblings or offspring of people with aortic aneurysms
Define aortic dissection
Tear of the intima that results in formation of a false channel within the media layer
What are the MC sites for aortic dissection?
- R lateral wall of ascending aorta (shear stress is highest)
- Descending thoracic just below ligamentum arteriosum
What populations are affected by aortic dissection?
- 70s-80s
- Males 2:1
What are the greatest risk factors for aortic dissection?
HTN (70% of pts)
Pregnancy (3rd trimester)
BLUNT trauma to aorta
How are aortic dissections classified?
DeBakey
Stanford
Explain DeBakey classifications
- For aortic dissections
- Type I: ascending, continues to aortic arch and many times beyond arch
- Type II: confined to ascending
- Type III: originates in descending aorta
Explain Stanford classifications
- For aortic dissections
- Type A: ascending aorta involved
- Type B: ascending aorta NOT involved
How are aortic dissections classified when they originate from ascending aorta?
Stanford A (Debakey I and II)
How does AAA present vs. aortic dissection?
- AAA is usually asymptomatic and a pulsatile mass may be felt
- Dissection is severe sudden onset of chest pain that radiates
What is the diagnostic test of choice for aortic dissections?
CT chest AND abdomen
What is the medical management of aortic dissections?
- BB for BP control
- Pain management (morphine)
When is surgery the better treatment of aortic dissections?
In acute proximal dissections
What is the MC cause of PAD?
Athero
What is the most modifiable risk factor of PAD?
Smoking
What are the MC sites of involvement of PAD?
Femoral and popliteal
What is the MC symptom of PAD?
Claudication
*However, less than 50% are symptomatic
Site of claudication is always:
Distal to the site of occlusion
What is a major risk factor for lower leg/foot PAD?
DM
What is the diagnostic test of PAD?
ABI
What is the treatment of PAD?
- Conservative
- Smoking cessation
- Risk factor reduction
- Platelet inhibitors
- Avoid compression stockings! Reduces blood flow to skin
What are examples of non-athero vascular disease?
- Fibromuscular dysplasia
- Thromboangiitis obliterans
- Vasculitis (Takayasu’s arteritis)
Describe fibromuscular dysplasia
- Hyperplastic disorder
- Stenosis and aneurysms of medium and small sized vessels
- MC involves renal and carotid arteries
- Females 30s-40s
How is fibromuscular dysplasia diagnosed?
“String of beads” appearance on renal angiography
Describe thromboangiitis obliterans
- Aka Buerger’s disease
- Inflamm occlusive disease involving small and medium vessels
- Distal upper and lower extremities only
- Asian/E. European men 40+ yo
What is the triad of S/S in thromboangiitis obliterans?
- Claudication of affected extremity
- Raynaud’s phenom
- Migratory superficial vein thrombophlebitis
What is the treatment of thromboangiitis obliterans?
No specific tx except smoking cessation
Describe Takayasu’s arteritis
- Inflamm and stenotic disease of medium and large sized arteries
- MC aortic arch and subclavian
- RARE
- Women less than 40 yo
- MC in Asia
How is Takayasu’s arteritis diagnosed?
Arteriography
What is the treatment of Takayasu’s arteritis?
Glucocorticoids may relieve general symptoms
Describe acute arterial occlusion of a limb
- Sudden loss of BF to an extremity
- Caused by embolism or thrombosis of an athero segment
What are the S/S of acute arterial occlusion of a limb?
6 P’s
- Pain
- Pallor
- Pulselessness
- Paresthesias
- Poikilothermia (coolness)
- Paralysis
Describe thoracic outlet syndrome
Compression of the neurovasc bundle (artery, vein or nerves) at thoracic outlet
What is Wright’s Maneuver?
- Hyperabduction test
- To diagnose thoracic outlet syndrome
- Radial pulse weakens or disappears when arm is abducted and ER on affected side
What is Adson’s test?
- To diagnose thoracic outlet syndrome
- Radial pulse weakens or disappears when pt rotates their head to affected side with extended neck following deep inspiration
What is the treatment of thoracic outlet syndrome?
- Conservative
- PT and avoid aggravating positions and activities
What is the MC type of peripheral artery aneurysm?
Popliteal (50% are bilateral)
What is the gold standard for diagnosing peripheral artery aneurysm?
U/S
Describe Raynaud’s phenomenon
- Paroxysmal digital ischemia
- Initial (excessive vasoconstriction) and recovery (vasodilation) phases
- Primarily fingers but can affect toes
What is the MC cause of Raynaud’s phenomenon?
Exaggerated vasoconstriction of distal arteries in response to cold or emotional stress
Types of Raynaud’s phenom and how they present?
- Primary (idiopathic): MC young women, symmetric involvement
- Secondary (a/w rheumatic dz): rare, digital pitting, ulceration, gangrene
Treatment of Raynaud’s phenom?
- Avoid cold weather
- Smoking cessation! (primary)
- CCB for severe cases of primary
Describe acrocyanosis
Arterial vasoconstriction and secondary dilation of capillaries and venules resulting in persistent (not episodic) cyanosis of the hands (and occasionally feet)
How does acrocyanosis present?
- Women, 30 yo or less
- Asymp
- Pain, ulcers, gangrene do NOT occur
Describe pernio (Chilbains)
- Vasculitis a/w exposure to cold
- MC in young women
- Raised erythematous lesions on distal lower extremities in cold weather
- Usually self limiting
