SM 137 Peripheral Vascular Disease Flashcards
What is Peripheral Arterial Disease?
PAD is stenotic or occlusive arterial disease caused by atherosclerosis outside the heart
How can PAD present?
PAD may be asymptomatic, but can also present as intermittent claudication and critical limb ischemia
What is intermittent claudication?
Claudication is pain caused by a lack of blood flow and can be intermittent with worsening during exercise
What is critical limb ischemia?
Severe lack of blood flow to the limbs that results in severe pain and/or gangrene in the limb
How does age affect PAD?
PAD worsens with age
How does the extent of symptoms felt in PAD effect survival?
Severe symptomatic PAD has worse survival than asymptomatic PAD
How is PAD affected by cadiovascular mortality?
PAD in the setting of MI results in greater long term risks of overall cardiovascular mortality
What is the Rutherford Class system?
System used to describe Limb Threatening Ischemia, on a scale of 0 - 6
How does asymptomatic PAD compare to CLTI?
Asymptomatic PAD tends to result in stable claudication while CLTI tends to result mortality or amputation
What can improve CLTI prognonsis?
CLTI tends to progress to amputation and death, with outcomes being improved by revascularization
What are the risk factors for PAD?
Atherosclerosis, cigarette smoking, diabetes, hypertension, hyperlipidemia, and family history
Why does CLTI lead to pain at rest in the setting of PAD?
A mismatch between arterial supply and demand leads to ischemia, pain, and tissue loss
How does CLTI alter vessels?
CLTI can lead to development of collateral flow, but the collateral flow is insufficient; also leads to turbulent flow
How does CLTI compare to intermittent claudication?
Both cause pain, intermittent claudication resolves with rest while CLTI does not; CLTI = tissue loss
What options exist for PAD treatment?
Medical treatment and Surgical + Medical combination
What does medical treatment for PAD entail?
Walking therapy and CV risk factor modification
Who receives medical treatment for PAD?
Asymptomatic patients only
What are the surgical treatments for PAD?
Endartectomy, bypass graft, and endovascular patients; all in conjunction with medical therapy
Who receives surgical therapy for PAD?
Surgical therapy is pursued in PAD patients with symptoms such as CLTI, claudication, etc.
How does CV risk factor modification work?
Use CV Risk assessment to treat risk factors such as diabetes, hypertension, smoking, starting statins and antiplatelet therapy
How does walking therapy improve intermittent claudication?
Increases pain free walking distance
What is endartectomy?
Surgical removal of a plaque from an artery wall, used in symptomatic PAD
What are emerging treatments for PAD?
Gene therapy with VEGF and Stem cell therapy with bone marrow; aims to grow blood vessels and improve blood flow
What is Aortic Dissection?
Dissection of blood between and along the laminar planes of the media, leading to the formation of a blodo-filled false-lumen
Where is the false lumen in Aortic Dissection found?
The false-lumen is found in the aortic wall, between the Intima and Media
How does the false lumen in Aortic Dissection affect perfusion?
Blood flow can be seriously occluded during systole as the flap of the false lumen expands and shunts blood into the anuerysmal area
What are the typical traits of someone affected by Aortic Dissection?
More common in males, higher in African Americans, predisposed by connective tissue disorders
What are the risk factors for Aortic Dissection?
Hypertension, connective tissue disorders, cocaine use
What are the possible causes of Aortic Dissection?
Medial degeneration and intimal thickening
What can cause medial degeneration, and what does this precipitate?
Deterioration of medial collagen and elastin as well as loss of smooth muscle cells can lead to Aortic Dissection
What can cause intimal thickening, and what does this precipitate?
Intimal thickening is caused by fibrosis, calcifications, and fatty acid depositions, which can lead to Aortic Dissection
How does Aortic Dissection present?
Severe pain + “ripping” sensation + malperfusion syndrome - leads to death if untreated
What are the signs of Malperfusion Syndrome?
Stroke, ischemia, hypotension
Which type of Aortic Dissection precipitates Cardiac Tamponade?
Type A Aortic Dissection leads to Cardiac Tamponade
What causes Type A Aortic Dissection?
Aortic Valve insufficiency, occlusion of coronary vessels, and rupture into the pericardium = surgical emergency
Which type of Aortic Dissection is a surgical emergency?
Type A, though complicated Type B is also treated with surgery
Which of of Aortic Dissection is treated medically?
Type B, but only if it’s uncomplicated
How does Type B Aortic Dissection present?
Occluded branches of the Aorta = Intestinal ischemia, renal failure, leg ischemia
How can Type B Aortic Dissection obstruct branch vessels?
The neo-intimal flap can obstruct other vessels when the heart contracts
How can Aortic Dissection be visualized?
Intravascular Ultrasound
What can make Type B Aortic Dissection complicated?
Malperfusion, rupture, pseudoaneurysm
What are the surgical options for treatment of Type B Aortic Dissection?
Open thoracoabdomnial aortic replacment and TEVAR
How does TEVAR treat Aortic Dissection?
Thoracic Endovascular Aortic Repair uses a stent to cover the intimal tear and re-expand true lumen, pushing the flap out of the true lumen
What is an Aneurysm?
An aneurysm is a widening of the diameter of a vessel by at least 50%
What are the risk factors for Abdominal Aortic Aneurysm?
Genetics, Hypertension, Age, Gender, Atherosclerosis
What underlies the pathophysiology of Abdominal Aortic Aneurysm?
Inflammation caused by inflammatory cells result in the release of Matrix metalloproteinases that degrade Collagen and Elastin, leading to thinning of the Media
What cells produce MMP’s and where are they found?
In the setting of AAA, MMP’s are made by smooth muscle cells, fibroblasts, and inflammatory cells in the wall of the Aorta
Which MMP correlates with aneurysm size?
MMP-9, underlies pathophysiology of AAA
How are Aneurysm’s described?
By location, size, shape, and etiology
What are possible shapes of aneurysms?
Fusiform or saccular
How does LaPlace’s Law dictate aneurysm rupture?
LaPlace Law: T = P * R; As diameter and pressure rise, wall tension rises, increasing risk of rupture
Where can aortic aneurysms be found?
Infrarenal, Juxtarenal, Pararenal, Suprarenal
What is Marfan syndrome and how does it relate to AAA?
Marfan is a congenital Fibrillin-1 defect, predisposes AAA since there is less functional elastic tissue in the Media at birth
What is Ehlers-Danlos syndrome and how does it relate to AAA?
Ehlers-Danlos is a congenital procollagen defect, predisposes AAA since there is less elastic tissue in the media at birth
How can AAA be diagnosed?
Abdominal Aortic Aneurysm can be detected and diagnosed with CT scan and Ultrasonography
What is the most common form of AAA?
Degenerative Abdominal Aortic Aneurysm is the most common form
What are Mycotic aneurysms?
Aneurysms caused by primary or secondary infection with bacteria or fungi, such as Staph, Salmonella, or Strep
Which microorganisms cause Mycotic aneurysms?
Staph, Salmonella, Strep
What are inflammatory aneurysms?
Dense periaortic fibrosis due to inflammation from inflammatory cells
What cells cause inflammatory aneurysms?
Immune cells = lymphocytes, plasma cells, macrophages, giant cells
What arteries does an Infrarenal AAA obstruct?
None - the Infrarenal AAA is below the level of the renal arteries
What arteries does a Juxtarenal AAA obstruct?
None - the Juxtarenal AAA is directly underneath the renal arteries
What arteries does a Pararenal AAA obstruct?
Both renal arteries, but no arteries above the renal arteries
What arteries does a Suprarenal AAA obstruct?
Both renal arteries as well as arteries above them, such as the mesenteric artery
How does an AAA present?
May be asymptomatic, but can also include abdominal or back pain with Aortic rupture causing pain and hypotension
What size does an Aortic Abdominal Aorta need to be for repair?
Must be greater than 5.5cm in diameter
What are the treatment options for AAA?
Open repair and endovascular repair
How does open repair treat AAA?
The patient is surgically operated on to remove the portion of the Aorta with the aneurysm and replace that portion with a graft
How does endovascular repair treat AAA?
A variety of stents can be inserted via the saphenous vein customized to the patient’s anatomy, with the only restriction being calcified arteries and concomitant aneurysms
