Vascular Disease, Disease of the Aorta, and Peripheral Vascular Disease Flashcards
Blood vessel diseases are common and important. What medical consequences do they have?
High morbidity and mortality
—more morbidity and mortality than any other
High cost
Often preventable w/ life style modifications
Often treatable if IDed early
Which vessels are most affected by vascular disease?
Arteries»_space;> Veins
Smaller arteries»_space;> bigger arteries
–smaller artery disease is often not recognized until later, where as bigger artery disease is more dramatic
What is the composition of a normal artery from inside to outside?
Single layer of endothelial cells in sub endothelial connective tissue
Internal elastic lamina - a dense elastic membrane that separates the ECs from the media
Smooth mm cells in layers of the media lamina
Surrounded by its lamina adventitia
What is the intima?
thin columnar ring of active endothelial cells on a dense and “pliable” basement membrane (the internal elastic lamina)
What is the media?
Layers of smooth mm in a metabolically active ECM composed of elastin, collagen, and glycosaminoglycans (where the action happens)
What is the adventitia?
Supportive fibrous tissue with nerves and blood vessels (vasoasorum)
What are the three types of arteries?
Large or elastic
Medium (or muscular or distributive)
Small arteries or arterioles
What are the characteristic features of large and medium arteries?
Vasa vasorum (vessels of the vessels) coring into the outer 1/2 - 2/3 of the media
A well defined external elastic lamina
Adventia (external to media) consisting of connective tissue with nerve fibers and the vasa vasorum
Describe the characteristics of the different types of veins
Veins are low pressure system conduits with thin walls
Large veins - intima, media, adventitia
Medium - have less adventitia
Venules - progressively less adventitia
Post cap venules - still less adventitia
Important structural features and functions of capillaries
Endothelial cells
Encircling pericytes
Thin walled
Function in gas exchange and nutrient exchange
Collective total CSA is massive
Arteries function as conduits. What are they conduits for?
Supply
- nutrients
- oxygen
- immuno-chemicals and cells for healing and growth
- pharmacologic agents
Bring
- infection
- inflammation
- cancer
- toxins
Arterial disease results in altered …
architecture
function
Atherosclerosis affects which vessels?
elastic and muscular arteries (large and medium vessels) like the aorta
Hypertension affects which vessels?
small muscular arteries and arterioles (capacitance vessels)
Aortic dissection
- what changes are seen in the aorta?
- what happens?
- Structural weakness of the vessel wall
- Loss of smooth mm cell or insufficient ECM
- Blood enters the wall and separates the various layers
- Causes rupture and/or obstruction of vessels branching off the aorta
Aortic aneurysm
- which layers are involved?
- result from?
- cause?
AN ABNORMAL BULGE IN THE VESSEL
Involve the entire thickness of the wall
- Result from the same structural weakness as dissections: loss of smooth mm cells or insufficient ECM
- Can be caused by: ischemia, genetic defects, defective matrix remodeling, trauma
- Cause rupture, thrombosis, and embolization
- Can predispose to dissection
Most pathology of the aorta will fit in one of the the following categories:
aneurysm
dissection
obstruction
aortitis (inflammation)
LaPlace’s Law
- what does it say
- what does this imply
A principle of physic that the tension on the wall of sphere is the:
- product of the pressure times the radius of the chamber
- is inversely related to thickness of the wall
The bigger the balloon’s radius gets as the pressure increases within, the greater the wall tension and the thinner the wall gets This increases the likelihood of rupture
Common causes of aortic aneurysms are factors that …
Examples
WEAKEN the aortic walls
Atherosclerosis HTN Infections such as TB, syphilis, strep, staph Trauma Congenital defects Marfans Ehlers-Danlos ETC
Aneurysms can be classified in various ways. What are these different ways?
Mechanism of dilation
Gross appearance
Location
What are the different classes of aneurysms according to the schema that classifies them according to mechanism of dilation?
True aneurysm - all three layers are involved
Pseudo-aneurysm - localized dissection - adventitia is not included in plaque formation
–BULDGE DUE TO CLOT FORMATION WITHIN THE INTACT ADVENTITIA
What are the different classes of aneurysms according to the schema that classifies them according to gross appearance?
Fusiform (like crescent shaped) - entire circumference of segment of vessel is enlarged
Saccular - side bulge (a cup-de-sac)
What are the different classes of aneurysms according to the schema that classifies them according to location?
Ascending aortic (thoracic) atherosclerotic Arch (thoracic) Descending (often continuous w/ infra diaphragmatic aneurysm and are called thoracoabdominal aortic aneurysms)
Atherosclerotic aneurysms
- where?
- risk factors?
Arch and the abdominal aorta
Risk factors
- cigarettes (smoking is strongest risk factors for abd aortic aneurysm)
- aging
- diabetes
- HTN
- dyslipidemia
What would you expect to see on radiography of someone that has an aneurysm?
Widened mediastinum
Shift of midline structures (e.g. trachea)
Aneurysms are defined by their size (depending on location). What are the sizes?
> 3.1 cm at aortic annulus
> 4.5 cm at aortic root
> 3.6 cm at ascending aorta
What is a typical presentation of an ascending thoracic aortic aneurysm?
Usually asymptomatic and discovered incidentally
Occasionally chest pain
Compression of local structures
Aortic regurgitation
What are the complications of an ascending thoracic aortic aneurysm?
Chronic aortic regurgitation
- LVH
- CHF
Dissection
Rupture (size dependent)
Tx of an ascending thoracic aortic aneurysm?
Control HTN
B-blockers
Serial imaging to assess progression
Surgery (> 5.5, > 4.5 Marfans, bicuspid aortic valve)
Descending thoracic aortic aneurysm
- usually associated with …
- chronic what?
- surgery when diameter > ?
- usually associated with atherosclerosis
- chronic aortic dissection
- surgery when diameter > 6.0 cm
Clinical manifestations of abdominal aortic aneurysm
Often asymptomatic
Back/flank or abd pain (expanding, inflamed, leaking)
Lower extremity claudication
Distal embolization
Abd aortic aneurysm complications
- peripheral embolization of adherent thrombus
- rupture risk strongly related to size and rate of expansion
- treat vascular risk factors and assess for underlying CAD
