0071643192.pdf

SYMPTOMS/EXAM

■ Vary with location and rapidity of valve failure
■ Findings of severe anemia (due to hemolysis)
■ Findings consistent with aortic/mitral regurgitation (acute or chronic)
■ Muted mechanical valve sounds, if mechanical valve failure

TREATMENT

■ Standard treatment for aortic/mitral regurgitation
■ Valve replacement

VALVETHROMBOSIS

Thrombus is more likely to form on a mechanical valve and can cause sys-
temic embolization or valve thrombosis.

SYMPTOMS/EXAM

■ If sudden, acute onset of hypotension, CHF
■ Muted mechanical valve sounds
■ May have a more gradual course

TREATMENT

■ Anticoagulation
■ Valve replacement

ARTERIAL CIRCULATORY DISORDERS

Arterial Aneurysms

Aneurysms can occur anywhere in the arterial system but are most common
in the abdominal aorta. Of those occurring in the peripheral arteries,
popliteal artery aneurysm is the most common (bilateral in >50%).

Arteries are composed of three layers: Tunica intima (inner layer), tunica me-
dia, and tunica adventitia (outer layer).

■ Atrue aneurysminvolves all three layers of vessel wall.
■ Afalse aneurysm orpseudoaneurysmcommunicates with the vessel lumen,
but is contained only by adventitia or surrounding soft tissues.

PATHOPHYSIOLOGY

■ Weakening of the media (cystic medial degeneration) →dilatation of the
vessel wall →true aneurysm.
■ Trauma to vessel wall →leakage of blood contained by adventitia or sur-
rounding soft tissue →pseudoaneurysm.
■ Aneurysms naturally enlarge over time.

Symptoms are caused by rupture (unlikely with peripheral artery aneurysms),
impingement of adjacent structures, thrombosis, or embolism.

ABDOMINALAORTICANEURYSM

Abdominal aortic aneurysms (AAAs) are most commonly trueaneurysms and
involve the infrarenalaorta. At this level an aortic diameter >3 cm =AAA.

CARDIOVASCULAR EMERGENCIES

Mechanical valve failure →

CHF, muted valve sounds

withpresence of regurgitation

murmur.

Valve thrombosis →CHF,

muted mechanical valve

soundswithoutregurgitation

murmur.