Forensic Pathology for Police - Brainshare Public Online Library

Cardiovascular System 219
Valve Disorders
Recall that there are four valves within the heart. The tricuspid valve separates the
right atrium and ventricle; the pulmonic valve separates the right ventricle from the
pulmonary artery; the mitral valve separates the left atrium and ventricle; and the
aortic valve separates the left ventricle from the aorta. Proper functioning valves
are necessary for normal heart function. Normal valves are relatively thin, and very
flexible. Properly functioning valves open fully to allow blood flow through the
valve when the cavity “in front of” the valve contracts, and close afterwards, thus
preventing “back-flow.” If a valve is firm (sometimes calcified), it cannot fully open,
and it is referred to as being “stenotic” or narrowed. If a valve does not fully close,
or if it is damaged so that when closed, it allows back-flow, then the valve is referred
to as being “regurgitant.”
Degenerative aortic stenosis occurs as a disorder of aging and is characterized by
rock-hard calcification with associated stenosis (Disc Image 10.24). For this reason,
it is sometimes referred to as “senile calcific aortic stenosis.” It is best thought of as
a “wear and tear” valve disorder. Patients with congenitally bicuspid (or unicuspid)
valves are prone to develop this disorder much earlier in life. With severe disease,
there is marked cardiomegaly, owing to the fact that the heart muscle must work
extra hard to push blood through the narrow valve opening. In addition, in severe
cases, the valve is not only stenotic, but also regurgitant, thus making the heart work
even harder.
Mitral valve prolapse (“myxomatous degeneration of the mitral valve” or “floppy
mitral valve syndrome”) is a disorder characterized by a floppy, rubbery mitral valve,
with redundant (excess) tissue, such that, on gross exam, the valve leaflets appear
ballooned or prolapsed (into the left atrium) (Fig. 10.11). The disorder is actually
fairly common and is typically an incidental autopsy finding; however, sudden death
Fig. 10.11 A case of mitral valve prolapse (MVP) characterized by a mitral valve that is redundant
and “billowing”