Aneurysm And Dissection Flashcards
Aneurysm
Most common in the aorta and heart
True aneurysm
Arterial or ventricular wall is thinned but intact
Blood remains within the confines of the circulatory system
False aneurysm
An extra vascular hematoma
Defect in vascular wall
Pulsating hematoma
Communicates with intravascular space
Saccular aneurysm
5-20 cm in diameter
Spherical
Fusiform aneurysm
< 20 cm in diameter
Matrix metalloproteinases
Degrades all components of ECM
Leads to inflammation causing a true aneurysm
Cystic medial degeneration
Of inner media due to thickening of wall (atherosclerosis)
Of outer media due to narrowing of vasa Vado rum (damage from htn)
Results in loss of SMCs, scarring and loss of elasticity, and inadequate ECM synthesis
Abdominal Aortic Aneurysm
Atherosclerosis is most frequent cause of aneurysms
Atherosclerotic plaque compresses-media
Compromises nutrient and waste diffusion
Results in media degeneration and necrosis
MMP from inflammation degrades ECM
Location of abdominal aortic aneurysm
Usually below the renal arteries and above the bifurcation
Rupture of abdominal aortic aneurysm
May cause massive often fatal hemorrhage
Larger the aneurysm- greater the risk of rupture
Aortic Dissection
Formation of a blood-filled channel within the aortic wall
Often ruptures
Patients that get aortic dissection
Hypertensive men 40-60 , > 90% of cases
Younger patients with systemic or localized abnormality of CT (Morgan syndrome)
Pregnancy, postpartum
Morphology of aortic dissection
Most of the time an intimal tear
Extends between the middle and outer third of the media
Often ruptures causing massive hemorrhage into pericardial cavity or pleural cavity or peritoneal cavity
Type A aortic dissection
Proximal lesions (ascending aorta or ascending and descending aorta)
More common
More dangerous
Type B Aortic Dissection
Distal lesions
Do NOT involve ascending aorta
Begin DISTAL to subclavian artery
