CONDUCTING AN AUTOPSY OF THE CARDIOVASCULAR SYSTEM
The heart is
a vital organ and the cardiovascular system is an important part of any autopsy. Statistically, the heart is the most common cause of sudden and unexpected death. Heart disease is also the leading overall cause of death in the United States.
What is included in an autopsy of the cardiovascular system? |
The cardiovascular system technically includes the heart
and all of the blood vessels in the body.
Typically, at autopsy the heart and major blood vessels (aorta and
vena cava) are examined as part of a standard autopsy. It is impossible to examine fully the miles
of blood vessels that course through the body. But it is important to keep in mind that
heart disease may be a contributing factor in other diseases that occur
throughout the body (e.g., hypertension is a contributing factor in kidney
disease).
Examination of the heart includes removing the chest plate
then taking the heart out of the pericardial sac (the protective sac around
the heart). The outside surfaces are
examined first and the blood vessels (coronary arteries) are dissected. The heart is opened to reveal the internal
surfaces and structures, including the valves and heart muscle
(myocardium). The muscle is then cut
to reveal the surface color, textures and other features. Finally, tissue sections are prepared to
examine under the microscope. |
What should I look for when conducting an autopsy of the cardiovascular system? |
The simplest answer is EVERYTHING. Since heart failure is the most common
cause of sudden death it is important to be aware of any abnormalities. There are a few heart-related problems that
are more common than others when determining cause of death. The blood vessels can have changes of
atherosclerosis (hardening and narrowing) that restrict blood flow and cause
a heart attack. Structural problems
with the heart valves (such as congenital bicuspid aortic valve, where the
aortic valve is formed by two leaflets rather than the normal three) can lead
to back up of blood flow and heart failure.
Structural heart valve problems usually can be seen when the heart
valve doesn't form normally (2 instead of 3 leaflets in aortic valve), or the
valve is abnormally thickened, such as in mitral valve prolapse. Heart valve leaflets should normally be
thin and semi-transparent.
Abnormalities in the heart wall, such as thickening from
hypertension and hypertrophic cardiomyopathy, can lead to abnormal electrical
impulses and sudden death. Infections
in the heart such as myocarditis can lead to heart failure. Chronic drug abuse can lead to many
alterations in the heart muscle and valves.
While there are many other kinds of heart abnormalities, medical
examiners try to confirm or disconfirm the most likely and/or common
explanations when determining cause of death.
As part of a typical autopsy, it is important to examine
all areas of the heart for abnormalities in the surfaces, the internal
structures such as heart valves and arteries, and changes in the coloration
of structure of the heart wall. And
remember that the heart is the center of the cardiovascular system (which
includes all of the blood vessels, so anytime there is bleeding in the body,
it may be related to the heart in some way.
Gross Images
Photograph of a normal heart (front)
Photograph of a normal heart (back)
Photograph 1 of a healthy aortic valve in a normal heart.
Photograph 2 of a healthy aortic valve
Photograph 1 of a healthy tricuspid valve in a normal heart.
Photograph 2 of a healthy tricuspid valve.
Photograph of cross-sections of a normal heart
Photograph of a healthy pulmonic valve in a normal heart.
Photograph of a healthy mitral valve in a normal heart.
Microscopic Images
Image of normal heart tissue (2x magnification)
Image of normal heart tissue (4x magnification)
Image of normal heart tissue (10x magnification)
Image of normal heart tissue (20x magnification)
|
What should I look for when trying to dis/confirm heart arrhythmia? |
It can be difficult to detect a cardiac arrhythmia, or an
abnormal electrical impulse conduction, at the autopsy stage, because it is
only possible to "see" a heart arrhythmia while a person is alive and the
heart is beating. Detecting
arrhythmias at autopsy depends on identifying structural or developmental
changes in the heart that can lead to an arrhythmia. Such abnormalities can include things
like heart muscle thickening (due to hypertension or hypertrophic
cardiomyopathy) or abnormal thickening or formation of heart valves.
Microscopic examination of tissue slides is an important
part of the autopsy examination when looking for arrhythmias. It is important to examine the cellular
structure of the tissue under the microscope, looking for things such as
thickening of heart muscle due to hypertension and hypertrophic
cardiomyopathy, two common causes of cardiac arrhythmia.
Even if your autopsy examination of the heart is normal,
that still doesn’t entirely exclude an arrhythmia as a possibility, since the
arrhythmic changes occur at the cellular, electrical and chemical level (areas that can’t be seen at autopsy). Even if there is no physical evidence of an
arrhythmia at the cellular level, arrhythmia may stay in the list of
potential diagnoses until it can be ruled out by process of elimination
(e.g., another cause can be confirmed). |
What should I look for when trying to dis/confirm heart attack due to atherosclerosis? |
Death to atherosclerosis is one of the easier things to
diagnose at autopsy because the symptoms are usually quite evident. The coronary arteries (vessels that supply
blood to the heart muscle) are typically hardened and narrowed, making it
difficult for blood to course through them and supply the heart muscle with
oxygen. At autopsy you would see the
cross sections of the arteries have yellow to yellow-white material building
up on the inside of the vessel, narrowing the lumen. This material is made of cholesterol, fat
and inflammatory cells. Calcium will
often be present making the arteries hard and inflexible.
In the heart muscle you would look for anything from
slight softening and light red pale discoloration, to a full-blown "heart
attack" with areas of heart muscle death and scarring (white firm
discoloration and hardening of the heart muscle wall).
Under the microscope you would look for narrowing of the
blood vessels with fat and cholesterol tissue in the blood vessel wall. Sometimes calcium will also be present in
the microscopic sections. If there are no signs of atherosclerosis when
initially examining the heart (with the naked eye), then there is no need to
pursue the microscopic exam.
Gross Images
Photograph 1 of coronary arteries with atherosclerosis
Photograph 2 of coronary arteries with atherosclerosis
Photograph 3 of coronary arteries with atherosclerosis
Photograph 4 of coronary arteries with atherosclerosis
Photograph of cross-sections of a coronary artery with atherosclerosis
Photograph of normal coronary arteries
|
<What should I look for when trying to dis/confirm congenital heart disease? |
Congenital heart disease is a broad topic, but in general
terms it involves the development of the heart. So at autopsy you would look for any
abnormal development or placement of the normal heart components (valves,
muscle, arteries, etc). An example
might be abnormal formation of the aortic valve so it only has two cusps
(bicuspid aortic valve); the aortic valve normally has three cusps. Abnormal thickening of the heart muscle can
also be considered a congenital heart disease as in hypertrophic
cardiomyopathy (see below).
Microscopic examination of the heart is not as important
in congenital heart disease since most of these abnormalities can be seen
grossly (with the naked eye) as abnormal structure development.
Gross Images
Photograph of a healthy aortic valve.
Photograph of a healthy tricuspid valve.
Photograph of cross-sections of a normal heart
Photograph of a healthy pulmonic valve in a normal heart.
Photograph of a healthy mitral valve in a normal heart
|
What should I look for when trying to dis/confirm hypertrophic cardiomyopathy? |
In hypertrophic cardiomyopathy the heart is enlarged and
thickened, often up to 2 or 3 times the normal heart size. This disease is primarily a problem with
over-development of the heart muscle cells, where they become enlarged and
"swollen" to many times the normal size.
When examining the heart with the naked eye, you would see an enlarged
and thickened heart with abnormal muscle tissue that often looks pale and
scarred (because the blood vessels cannot keep up with the oxygen demands of
the enlarged cells). The rest of the
heart structures are typically normal.
Under the microscope you would see abnormally large muscle
fibers without any inflammation or other defects. The fibers are many times the normal
size. Also you may see fibrosis
(scarring) of the heart muscle wall, again due to the increased oxygen demand
of the enlarged heart.
Gross Images
Photograph of a heart with hypertrophic cardiomyopathy
Photograph of a heart with hypertrophic cardiomyopathy compared with a normal heart
Photograph of cross-sections of a heart with hypertrophic cardiomyopathy
Microscopic Images
Image of HCM heart tissue (2x magnification)
Image of HCM heart tissue (4x magnification)
Image of HCM heart tissue (10x magnification)
Image of HCM heart tissue (20x magnification)
|
What should I look for when trying to dis/confirm myocarditis? |
Myocarditis (inflammation of the heart) is typically due
to a viral infection, such as that from Coxsackie B virus. At gross examination (examining the heart
without the aid of a microscope), the heart can range from being totally
normal, to having a diffuse tan pale discoloration and softening. A yellowy
film (like an egg yolk) may coat the surface of the heart. The other heart structures are typically
normal.
Microscopically the hallmark of viral myocarditis is
individual heart muscle fiber death (myocyte necrosis) with associated
inflammation (usually due to lymphocytes).
Gross Images
Photograph of cross sections of a heart with myocarditis
Photograph of exterior of a heart with myocarditis
Microscopic Images
Image of heart tissue with myocarditis (2x magnification)
Image of heart tissue with myocarditis (4x magnification)
Image of heart tissue with myocarditis (10x magnification)
Image of heart tissue with myocarditis (20x magnification)
|
What should I look for when trying to dis/confirm drug use? |
Complications of drug use seen in the heart typically center on two areas. The first is infections of the heart valves (endocarditis) where bacteria from the blood stream get stuck on the valve surfaces as red-tan growths that can eat away the valve. This type of heart disease is only seen in chronic intravenous drug users (heroin, cocaine).
The other type of heart change is seen in chronic use of stimulant medications or drugs. This is typically associated with “hard” drugs like methamphetamine or cocaine, but can also be seen in chronic use of other stimulants like caffeine or ephedrine (found in a lot of “herbal” teas, sports drinks or “stay awake” pills). With these heart changes you will see thickening and enlargement of the heart like that seen in hypertrophic cardiomyopathy. The heart may be 1 ½ to 2 times the normal size with thickened walls.
Microscopically you will see changes similar to hypertrophic cardiomyopathy with thickened heart muscle cells. The changes in chronic drug use are often similar but less severe than those seen in hypertrophic cardiomyopathy, but not always. |
When writing an autopsy report, what should I include in a thorough description of the cardiovascular system? |
When writing an autopsy report of the heart it is important to examine and record the following areas:
- Overall appearance, coloration and size of the heart (including weight) is important.
- The presence or absence of abnormal structures visible on the outside of the heart.
- The cut sections of the coronary arteries must be examined for atherosclerosis (narrowing) noting the approximate percentage and areas. Typically the narrowing can be described as 25%, 50%, 75%, 90% or occluded (100%).
-
Slicing of the heart is done to describe the color and consistency of the muscle walls, looking for areas of scarring or other discoloration. You should also note the thickness of the left ventricle in cases of heart enlargement. The left ventricle thickness is measured on the "septum" and on the "free wall". It is a measurement taken of the muscle wall thickness on of the cross sections of the heart examination. The measurement should not include the muscle bulges on the inside of the heart chamber (papillary muscles), but only the wall muscle itself.
- Opening of the heart reveals the heart valves and inside surfaces of the great vessels. You should note the appearance of the heart valves (normally thin and pliable), the number of valve leaflets and any other abnormalities seen.
|
|
|
|