Valvular Heart Disease

Question 1

What changes in heart sounds are associated with

mitral valve stenosis?

Answer 1

Mitral stenosis is associated with an ‘opening snap’ that occurs
in early diastole and a rumbling diastolic murmur heard best at
the axilla or apex.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 35.

Question 2

What is valvular stenosis?

Answer 2

Valvular stenosis is a narrowing of the valvular opening, or
orifice, that results in a restriction of flow when the valve is open.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 496.

Question 3

How do the hemodynamic goals for mitral
regurgitation differ from those of mitral stenosis? In
what ways are they similar?

Answer 3

In mitral regurgitation, your goal is to maintain an increased
heart rate and decreased afterload while the goal in mitral
stenosis is to maintain a normal or decreased heart rate and
normal afterload. In both disorders, you should maintain normal
sinus rhythm, avoid increases in pulmonary vascular resistance,
and maintain preload at normal to increased levels.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 498-500.

Question 4

What therapies have been shown to be effective in
the treatment of symptomatic mitral valve
regurgitation?

Answer 4

Angiotensin-converting enzyme inhibitors, beta-blockers, and
biventricular pacing have been shown to reduce the regurgitant
volume and improve exercise tolerance in patients with
symptomatic mitral valve regurgitation.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 37-38.

Question 5

What changes does mitral regurgitation produce in

the pulmonary artery occlusion waveform?

Answer 5

A V wave appears on the pulmonary artery occlusion
waveform. Although pulmonary artery occlusion pressure can
be an unreliable estimate of LVEDV in patients with chronic
mitral regurgitation, changes in the V wave amplitude can help
estimate changes in the degree of mitral regurgitation.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 37-38.

Question 6

How do heart sounds change with mitral

regurgitation?

Answer 6

There is typically a holosystolic murmur at the apex that
radiates to the axilla.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 37-38.

Question 7

How does the regurgitant fraction correlate with

severity of disease in mitral valve regurgitation?

Answer 7

A regurgitant fraction less than 30% is considered mild, 30-60%
is associated with moderately severe symptoms, and a
regurgitant fraction above 60% is considered severe.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 410-411.

Question 8

What two factors determine the pressure gradient

across the mitral valve in mitral valve regurgitation?

Answer 8

The systemic vascular resistance and the left atrial pressure. A
decrease in SVR or an increase in left atrial pressure will
decrease the regurgitant volume.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 410.

Question 9

What three factors determine the regurgitant volume

in mitral regurgitation?

Answer 9

The size of the mitral valve opening, the heart rate, and the
pressure gradient across the valve.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 37.

Question 10

What is the primary disturbance caused by mitral

valve regurgitation?

Answer 10

Mitral valve regurgitation is associated with a decrease in the
forward flow of blood (stroke volume) due to the backward flow
of blood into the left atrium during systole.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 410.

Question 11

What are the most common causes of acute mitral

valve regurgitation?

Answer 11

Acute mitral regurgitation can occur as a result of myocardial
infarction, papillary muscle dysfunction, chordae tendinae
rupture, trauma to the chest, or infectious endocarditis.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 410.

Question 12

What are the primary anesthetic management

objectives for the patient with mitral valve stenosis?

Answer 12

Avoid hypervolemia which can precipitate pulmonary edema.
Nitrous oxide should be used cautiously as it may increase
pulmonary vascular resistance. Drugs that predispose the
patient to tachycardia such as pancuronium or ketamine should
be used cautiously or avoided altogether. Intraoperative
tachycardia can be controlled with opioids (with the exception of
meperidine which can cause tachycardia), by increasing the
depth of anesthesia or administering a beta-blocker.
Phenylephrine is preferred over ephedrine for decreases in
blood pressure as it doesn’t increase the heart rate. Epidural
anesthesia is generally preferred over spinal anesthesia
because the decrease in sympathetic activity is not as dramatic.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 409-410.

Question 13

What is mitral valve prolapse?

Answer 13

Mitral valve prolapse occurs when one or both mitral valve
leaflets dip into the left atrium during systole. It can occur with
or without mitral regurgitation.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 38.

Question 14

What valvular abnormalities can be caused by mitral

stenosis?

Answer 14

Mitral stenosis results in an increase in right ventricular volume.
Severe right ventricular dilation can cause tricuspid and/or
pulmonary valve insufficiency.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 408.

Question 15

What changes in heart sounds are associated with

mitral valve prolapse?

Answer 15

Mitral valve prolapse is associated with a midsystolic click and a
late systolic murmur.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 39.

Question 16

How can mitral valve stenosis result in pulmonary

edema?

Answer 16

The increase in left atrial pressure associated with mitral
stenosis is transmitted into the pulmonary vasculature. As
pulmonary venous pressure increases above approximately 25
mmHg, fluid can leak into the pulmonary interstitial space
resulting in a decrease in pulmonary compliance and increased
work of breathing. If the change in pulmonary venous pressure
occurs over a long period of time, an increase in pulmonary
lymph flow can partially compensate for the fluid accumulation.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 35.

Question 17

What is the compensatory mechanism that maintains
stroke volume in patients with mild mitral stenosis?
What factors may cause this mechanism to fail?

Answer 17

Left atrial pressure increases, which increases the blood flow
through the mildly narrowed mitral valve opening. The increase
in atrial pressure will fail to maintain stroke volume during
tachycardia or atrial fibrillation.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 34-35.

Question 18

How are the left atrium, pulmonary vasculature, and

right ventricle affected by mitral stenosis?

Answer 18

As flow through the mitral valve opening into the left ventricle is
decreased, left atrial pressure increases, resulting in left atrial
hypertrophy and distention. The increased pressure is
transmitted into the pulmonary vasculature as the volume of
pulmonary blood increases. This increased pulmonary vascular
pressure represents an increase in right ventricular afterload
and will cause right ventricular hypertrophy and failure.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 498.

Question 19

How is left ventricular volume affected by mitral

stenosis and why?

Answer 19

As the mitral valve orifice narrows, a pressure gradient
develops across the valve as a compensatory mechanism to
maintain flow through the valve. As the valve opening
decreases and the pressure gradient increases, the flow of
blood through the opening decreases and left ventricular
volume decreases.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 497.

Question 20

What cardiac conditions may develop from mitral

stenosis?

Answer 20

Congestive heart failure, pulmonary hypertension, and right
ventricular failure
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 34-35.

Question 21

What effect does rheumatic heart disease have on
the mitral valve? What patients does it affect most?
How quickly does it develop?

Answer 21

The incidence of mitral stenosis is higher in females. Over a
period of 20-30 years, rheumatic fever causes the mitral valve
leaflets to become thickened, the commissure may fuse, and
the leaflets and annulus may become calcified.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 34.

Question 22

What is the normal mitral valve area?

Answer 22

The normal mitral valve area is 4-6 cm2.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 497.

Question 23

What is the most common cause of mitral stenosis?

Answer 23

Rheumatic heart disease
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 34.

Question 24

What are the most common symptoms of valvular

disorders in general?

Answer 24

The most common symptoms associated with valvular disorders
as a whole are congestive heart failure, dysrhythmias, syncope,
and angina.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 497.

Question 25

What is a mixed valvular disorder?

Answer 25

It is a combination of stenosis and insufficiency, although one disorder is usually considered dominant. Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis, MO: Elsevier Saunders Company; 2014: 496.

Question 26

What is valvular insufficiency?

Answer 26

Valvular insufficiency is the incomplete closure of a valve which allows blood to regurgitate back into the previous chamber, resulting in inhibited forward flow. Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis, MO: Elsevier Saunders Company; 2014: 496.

Question 27

What range of mitral valve areas are associated with dyspnea at rest? Dyspnea on moderate exertion? Asymptomatic mitral stenosis?

Answer 27

A mitral valve area of 1 cm2 is associated with a transvalvular gradient of 20 mmHg and dyspnea at rest or with minimal exertion. A mitral valve area between 1 and 1.5 cm2 is associated with dyspnea on moderate exertion. A mitral valve area between 1.5 and 2 cm2 is considered mild and patients are typically asymptomatic. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 409.

Question 28

What is the average life span of a patient with aortic | stenosis if valve replacement is not performed?

Answer 28

Approximately 75% of patients with severe aortic stenosis will die within three years if aortic valve replacement surgery is not performed. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 41.

Question 29

What are the main anesthetic goals for a patient with | aortic regurgitation?

Answer 29

The heart rate should be maintained normal to high, the afterload should be decreased, myocardial depression should be avoided, normal sinus rhythm should be maintained, and preload should be normal to high. Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis, MO: Elsevier Saunders Company; 2014: 503.

Question 30

What is the typical medical management for a | patient with aortic regurgitation?

Answer 30

Afterload reduction with ACE inhibitors is often employed to reduce the transvalvular gradient and facilitate forward flow of blood out of the left ventricle. Digitalis and diuretics are often utilized as well. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 417.

Question 31

How does the prognosis of acute aortic regurgitation | differ from chronic aortic regurgitation?

Answer 31

In acute aortic regurgitation, the left ventricle does not have adequate time to compensate for the increased left ventricular volume and left ventricular failure, pulmonary edema, and cardiovascular collapse may ensue. Patients with chronic aortic regurgitation may not exhibit symptoms for a long period of time and during normal activity, the symptoms are not incapacitating. As long as the mitral valve patency does not result from left ventricular hypertrophy, the pulmonary circulation is preserved. End-stage disease is typically characterized by myocardial failure, a decrease in cardiac output, dramatic elevations in LVEDV, and pulmonary edema. Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis, MO: Elsevier Saunders Company; 2014: 502.

Question 32

How does an increase in diastolic blood pressure | affect the severity of aortic regurgitation?

Answer 32

An increase in the diastolic blood pressure increases the backward pressure gradient which results in an increase in the proportion of stroke volume that regurgitates back into the left ventricle. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 416.

Question 33

How does bradycardia affect the severity of aortic | regurgitation?

Answer 33

The decrease in heart rate increases the diastolic time which adversely affects the patient's condition by increasing the proportion of the stroke volume that regurgitates backward through the aortic valve. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 416-417.

Question 34

What are the principal hemodynamic effects of aortic | regurgitation?

Answer 34

Because of the backward flow of blood through the aortic valve during diastole, the left ventricle becomes volume overloaded and distended. The arterial diastolic pressure and systemic vascular resistance are decreased, which helps maintain forward flow of blood into the arterial tree. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 416-417.

Question 35

What are the most common conditions affecting the | aortic valve leaflets that result in aortic regurgitation?

Answer 35

Rheumatic fever, bicuspid aortic valve, infective endocarditis, and the use of anorexigenic (diet) drugs such as fenfluramine or dexfenfluramine. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 42.

Question 36

What is aortic regurgitation?

Answer 36

Aortic regurgitation is the failure of the aortic valve leaflets to close properly due to disease of the aortic root or of the leaflets themselves. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 42.

Question 37

What are the primary anesthetic management goals | for a patient with aortic stenosis?

Answer 37

Because left ventricular filling is so dependent upon an appropriately-timed atrial contraction, maintenance of normal sinus rhythm is very important. The development of a junctional rhythm or atrial fibrillation can result in congestive heart failure and hypotension. Hypotension must be treated aggressively as the corresponding decrease in myocardial perfusion can decrease left ventricular function and result in a decrease in cardiac output which would further worsen hypotension. Sustained increases in heart rate must be avoided as the ventricles need adequate time for ventricular filling. Conversely, severe bradycardia can result in overfilling and ventricular distention. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 41.

Question 38

Why is atrial fibrillation or a junctional rhythm so | detrimental to a patient with aortic stenosis?

Answer 38

The decreased pressure gradient that exists between the left atrium and left ventricle in aortic stenosis limits left ventricular filling dramatically. Because left ventricular filling is so dependent upon atrial contraction, loss of atrial systole can result in congestive heart failure or hypotension. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 415.

Question 39

How is left ventricular compliance affected by aortic | stenosis?

Answer 39

Compliance decreases as the left ventricle hypertrophies, resulting in diastolic dysfunction. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 414-415.

Question 40

What is the anesthetic of choice in patients with | mitral regurgitation?

Answer 40

General anesthesia is the anesthetic of choice. Neuraxial anesthesia is not contraindicated, but the dramatic decreases in sympathetic activity and associated decrease in blood pressure should be strongly considered prior to implementation. Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis, MO: Elsevier Saunders Company; 2014: 500.

Question 41

How are myocardial oxygen supply and demand | affected by aortic stenosis?

Answer 41

The myocardial demand is increased due to ventricular hypertrophy and the supply is decreased as the extraordinary compression of intramyocardial vessels during systole restricts arterial flow to the myocardium. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 414-415.

Question 42

How would the presence of aortic regurgitation affect | your selection of muscle relaxants for a patient?

Answer 42

Tracheal intubation can be accomplished with any of the muscle relaxants, but because you wish to maintain a normal to elevated heart rate, pancuronium might be a good choice for its vagolytic properties while the potential for succinylcholine to cause bradycardia should be considered prior to administration. Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis, MO: Elsevier Saunders Company; 2014: 503.

Question 43

What symptoms are associated with severe aortic | stenosis?

Answer 43

The classic triad of symptoms that accompany severe aortic stenosis are angina, syncope, and congestive heart failure. Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis, MO: Elsevier Saunders Company; 2014: 501.

Question 44

What valve area and transvalvular gradient are | associated with severe aortic stenosis?

Answer 44

A valve area less than 0.8 cm2 and a transvalvular gradient greater than 50 mmHg are considered to be severe aortic stenosis. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 40.

Question 45

What is the initial compensatory mechanism as | aortic stenosis develops?

Answer 45

The initial compensatory mechanism for aortic stenosis is an increase in left ventricular pressure to maintain flow through the narrowed aortic valve. This results in a pressure gradient across the valve. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 40-41.

Question 46

What is the normal aortic valve area?

Answer 46

2.5 - 3.5 cm2 Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 40.

Question 47

What are the risk factors for the development of | aortic stenosis?

Answer 47

The risk factors for aortic stenosis are similar to those for ischemic heart disease (e.g. hypertension and hypercholesterolemia). Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 40.

Question 48

What is aortic stenosis and what are the two factors | that predispose patients to developing this disorder?

Answer 48

Aortic stenosis is the narrowing of the aortic valve which results in obstruction of blood flow into the aorta. It is the result of degeneration and calcification of the leaflets of the aortic valve or the presence of a bicuspid rather than a normal tricuspid valve. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 40.

Question 49

What factors decrease the amount of prolapse in | patients with mitral valve prolapse?

Answer 49

Any factor that maintains a larger ventricular volume will decrease the degree of prolapse. Hypertension, vasoconstriction, drug-induced myocardial depression, and increased preload will decrease the degree of prolapse. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 38-39.

Question 50

What factors increase the degree of prolapse in | patients with mitral valve prolapse?

Answer 50

As a general rule, the larger the ventricle is, the less prolapse the mitral valve will exhibit (the more the ventricle empties, the greater the amount of prolapse). Factors that increase left ventricular contractility or decrease SVR will result in an increased degree of prolapse. Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases. 6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 39.

Question 51

What are the symptoms of mitral valve prolapse?

Answer 51

Although many patients are asymptomatic, patients who do exhibit symptoms may experience chest pain, arrhythmias, mitral regurgitation, infectious endocarditis, embolism, and even sudden cardiac death. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 413.

Question 52

What connective tissue disorder exhibits a | particularly high incidence of mitral valve prolapse?

Answer 52

Although mitral valve prolapse is more common in patients with any connective tissue disorder, it has a particularly high incidence in patients with Marfan syndrome. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 413.

Question 53

What percent of the population has mitral valve | prolapse?

Answer 53

Mitral valve prolapse was previously estimated to occur in about 5% of the general population and 15% of women, but newer data demonstrates that the actual incidence is between 1.6% and 2.4% in the U.S. population. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 413.

Question 54

How is cardiac output affected by aortic stenosis?

Answer 54

The cardiac output is typically normal at rest but the heart cannot increase output appropriately during periods of exertion, resulting in angina and dyspnea, even in the absence of coronary artery disease. Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill; 2013: 414.