Vascular Pathology-Fung Flashcards
WHat is an aneurysm?
localized abnormal dilation of the blood vessel or the heart
What are the different types of aneurysms?
Congenital or acquired
True aneurysm or false aneurysm
Saccular or fusiform
What is a true aneurysm?
Involves an intact attenuated arterial wall or thinned ventricular wall
could be saccular or fusiform
What are some examples of true aneurysm?
Atherosclerotic
Syphilitic
Congenital
Ventricular following transmural infarction
What’s the deal with atherosclerotic true aneurysms?
atheromas increase distance of diffusion of nutrients to the media of the bv.
necrosis of the media leaves it vulnerable to rupture–aneurysm.
What is a false aneurysm?
Also called pseudo-aneurysm
Defect in the vascular wall leading to an extravascular hematoma that freely communicates with the intravascular space
What is an example of a false aneurysm?
Ventricular rupture with pericardial adhesion
what is a saccular true aneurysm?
Spherical outpouchings involving only a portion of the vessel
5-20 cm in diameter
What is a fusiform true aneurysm?
Diffuse, circumferential dilation of a long vascular segment
Up to 20 cm in diameter
Involve extensive portions of the aortic arch, abdominal aorta, iliac arteries
WHat is the function of endothelial cells in the vascular structure?
Maintain non-thrombogenic blood-tissue interface Modulate vascular resistance Metabolize hormones Regulate inflammation Regulate cell growth
What is the function of smooth muscle cells in the vascular structure?
Proliferate when stimulated Synthesize: ECM--> Collagen Elastin Proteoglycans Growth factors Cytokines
What is the ECM of the vascular structure composed of?
Elastin
Collagen
Glycosoaminoglycans
What is the order of the layers of a muscular artery?
endothelium internal elastic lamina tunica media external elastic lamina adventitia
What is a developmental berry aneurysm?
Occur in cerebral vessels
Majority occur sporadically
Some are genetic
Referred as congenital but not present at birth; develop over time
What are some genetic disease that can lead to the development of berry aneurysms?
AD polycystic kidney disease, Ehler-Danlos syndrome, NF1, Marfan syndrome
What are some risk factors for the development of berry aneurysms?
cigarettes
HTN
What are atriovenous fistulas?
Small direct connections between arteries and veins that bypass capillaries
AV fistulas occur due to….?
Developmental defects
Rupture of arterial aneurysm into an adjacent vein
Penetrating injuries that pierce arteries and veins
Inflammatory necrosis of adjacent vessels
Iatrogenic
What is fibromuscular dysplasia?
Focal irregular thickening of the walls of medium and large muscular arteries
Results in luminal stenosis
Fibromuscular dysplasia is most frequently found in which demographic?
young women
Can CT diseases cause aneurysms?
yes, anything that weakens the vascular wall can cause an aneurysm
Marfan syndrome: defect of fibrillin
Ehlers-Danlos syndrome: defect in the synthesis or structure of fibrillar collagen
Vitamin C deficiency: altered collagen cross-linking
Loeys-Dietz syndrome: defect in elastin, collagen I and III
Why is inflammation extra bad with aneurysms?
Inflammation that alters the balance of synthesis and destruction of collagen
Increased matrix metalloproteases (MMP) that degrade the extracellular matrix
What are the 2 most important predisposing risk factors for aneurysms?
HTN–Ascending Aortic Aneurysm
Atherosclerosis–AAA
What’s the deal with the abdominal aortic aneurysm?
Remember-the most common location for an atherosclerotic aneurysm
caused by cystic medial degeneration & MMP
There are the inflammatory & mycotic types.
Can be saccular or fusiform.