ScholarRX: Aortic Disease Flashcards
what is aortic stenosis?
a condition in which there is a narrow left ventricular outflow tract caused by failure of the aortic valve to open up completely
aortic stenosis occurs when the aortic valve leaflets become stiff and unable to fully open, making it difficult for the heart to pump blood out to the rest of the body.
the heart has to work harder to pump blood through this tight opening to deliver blood to the rest of the body
if the restriction of blood from the LV becomes severe enough, it can lead to heart failure because there will be a lack of oxygen and nutrients to the body
what causes aortic stenosis?
the stiffening of the aortic valve leaflets, which is triggered by inflammation, has three
main causes:
- degenerative calcification, seen with aging;
- congenital bicuspid valve (born with two leaflets instead of three)
- rheumatic heart disease.
what’s the difference between aortic sclerosis and aortic stenosis?
over time, inflammation causes the aortic valve to scar, thicken, and eventually calcify and stiffen
aortic sclerosis results when calcification and thickening of the aortic valve happens without any restriction of blood flow from the left ventricle
in contrast, aortic stenosis is characterized by obstructed blood flow
aortic sclerosis eventually leads to aortic stenosis
what are the risk factors for aortic stenosis?
- old age
- male sex
- smoking
- HTN
- high LDL levels
- DM
these risk factors are the same as those for coronary artery disease
what is coronary artery disease?
CAD occurs when plaque builds up in the arteries that feed the heart muscle, narrowing the arteries and eventually cutting off blood flow to the heart muscle
what is a congenital biscupid aortic valve?
bicuspid aortic valve is the most common congenital malformation of the aortic valve and is present in 1%‐2% of the population
the two leaflets of the bicuspid valve are not able to hold up as well to the normal wear and tear on the aortic valve and tend to calcify more easily than a normal, tricuspid valve
aortic stenosis due to a bicuspid valve develops at an earlier age, in the 40s or 50s, rather than the older age (>70‐80 years) associated with degenerative aortic stenosis
what is an aortic aneurysm?
dilation of the aortic root which is associated with a biscupid aortic valve
this is like the stretching of a balloon and puts the aorta at risk of dissection or rupture
when a bicuspid valve is identified, the patient should also be screened for aortic root aneurysm
what is rheumatic heart disease?
the result of an autoimmune disease called rheumatic fever, which is caused by an infection with the bacteria Streptococcus pyogenes
if the strep infection is left untreated, it allows the body to create antibodies to a surface protein on the bacteria (M protein) that mimics a protein present on the lining of the heart
this in turn directs the body’s immune system to attack the lining of the heart, causing inflammation and scarring of the valves of the heart, most commonly the mitral and aortic valves
what are the symptoms of aortic stenosis?
- angina
- syncope
- dyspnea
- heart failure
survival starts to decrease with the onset of symptoms ):
what causes angina in aortic stenosis? what is the prognosis?
it is caused by decreased blood flow through the coronary arteries to the myocardium
angina occurs because the coronary arteries open from the aorta directly after the aortic valve
decreased flow from the left ventricle through the stenotic valve leads to decreased coronary blood flow and angina
patients with angina have an average 5‐year survival
what causes syncope in aortic stenosis? what is the prognosis?
it’s due to transient decrease of blood flow to the brain, again because of the tight stenotic valve
these patients have an average 3‐year survival
what causes dyspnea in aortic stenosis? what is the prognosis?
this is a symptom of heart failure!!
it occurs because the pressure load on the ventricle eventually causes it to hypertrophy and then causes the muscle to weaken
this leads to backup of fluid into the lungs, dyspnea, and even pulmonary edema
these patients have an average 2‐year survival
what is the main sign associated with aortic stenosis?
because patients are often asymptomatic, it’s likely that AS will be discovered on a routine exam or during a check for another condition
the main sign associated with AS is a systolic crescendo‐decrescendo murmur
the intensity of the murmur changes with how much blood flow is going through the aortic valve –> ↓ aortic blood flow = quieter murmur, ↑ aortic blood flow = louder murmur
how does the murmur heard with aortic stenosis change?
the intensity of the murmur changes with how much blood flow is going through the aortic valve:
amount of blood flowing through the aortic valve depends on the position of the patient
the murmur will become quieter when the patient bears down (Valsalva) or stands because both lead to less blood flow through the aortic valve
the murmur will become louder when the patient squats because this leads to more blood flow through the aortic valve
what is pulses parvus et trades?
delayed and dulled pulse felt in the carotid arteries of the neck
what are some signs of heart failure that can be see during a PE in a patient with aortic stenosis?
- S3 or S4 gallop (an extra heart sound heard on heart exam)
- atrial fibrillation (an irregular heart rhythm)
- a larger and more lateral point of maximal impulse, or PMI (the point where the
heart hits the chest wall) - crackles heard on lung exam
- jugular venous distention, or JVD (bulging of the jugular veins in the neck)
- peripheral edema (fluid buildup in the extremities)
what is the effect of aortic stenosis on blood flow and the left ventricle?
instead of pumping blood through a wide‐open valve, the LV has to pump through a tight, narrowed valve
this pressure load on the LV causes left ventricular hypertrophy over time and eventually may lead to weakening of the heart muscle due to fatigue
damage to the heart muscle can be irreversible, which is one of the reasons patients with AS should be treated before the LV is affected
what does it mean that patients with severe aortic stenosis are preload dependent?
the LV is trying to pump blood through the pinhole‐sized opening of the stenotic aortic valve and to do so the LV needs enough pressure, but it also needs enough fluid, like a full tank
the pressure and volume flowing through the right side of the heart are controlled by the tone of the venous blood vessels and if these veins dilate, they can hold a lot of fluid but it will also decrease the forward pressure into the LV
so anything that drops the preload by dilating the veins can be potentially dangerous for patients with severe AS
so do NOT give nitroglycerin because it dilates blood vessels –> this is tricky because it’s usually given to patients in the ER who present with chest pain…
how do you diagnose aortic stenosis?
- echocardiogram
this is the preferred test and will usually show
thickening and calcification of the aortic valve along with any malformation of the valve
- doppler echocardiography
used to determine the amount of flow through the aortic valve and the pressure
gradient between the left ventricle and the aorta caused by the narrowed
valve
- left and right heart catheterization
this is the confirmatory gold standard test if the Doppler
echocardiogram is indeterminate, but the patient is having symptoms of AS.
how do we treat aortic stenosis?
if a patient with severe AS is asymptomatic, watchful waiting with repeat echocardiograms is recommended
however, once patients develop symptoms, their survival decreases
therefore, the ideal moment for surgical intervention is the day before the patient develops symptoms –> of course, that’s
impossible in practice, but it illustrates the point that finding the right timing for surgery is a delicate balance
aortic stenosis is not conventionally treatable with medications, although blood pressure control is recommended.
what is the only definite treatment for patients with symptomatic aortic stenosis?
valve replacement
A 45‐year‐old man from the United States presents to clinic with shortness of breath
and a feeling like he’s going to pass out when he runs. Listening to his heart reveals a
crescendo‐decrescendo systolic murmur radiating to the carotids, and
echocardiogram finds thickening and calcification (sclerosis) of the aortic valve.
What else is most likely be found on echocardiogram?
A. Aortic valve with one leaflet
B. Aortic valve with three leaflets
C. Aortic valve with three leaflets and mitral valve sclerosis
D. Aortic valve with two leaflets
E. Vegetations on the aortic leaflets
D. Aortic valve with two leaflets
AS is not a very common diagnosis in middle‐aged patients, and there is most likely some kind of malformation of his aortic valve to allow this sclerosis to happen at such an early age
If our patient were found to have three aortic valve leaflets and sclerosis of the mitral valve this would suggest a history of rheumatic heart disease
You are listening to the heart sounds of a patient with severe AS. As you listen, you
feel the carotid arteries in the neck of the patient. What do you most likely feel?
A. Carotid pulses that happen after the heartbeat and feel weak
B. Carotid pulses that happen before the heartbeat
C. Carotid pulses that happen with the heartbeat
D. Carotid pulses that happen with the heartbeat and also have a humming feeling
to them
E. Carotid pulses that happen with the heartbeat and are very strong
A. Carotid pulses that happen after the heartbeat and feel weak
this is pulsus parvus et tardus
A 78‐year‐old man with severe aortic stenosis presents to the emergency room
complaining of chest pain. Which of the following medications should not be
prescribed?
A. Nitroglycerin
B. Diuretic
C. β‐Blocker
D. Calcium channel blocker
A. Nitroglycerin
it decreases preload by causing vasodilation
in severe AS, patients are preload dependent, and dropping the preload with nitroglycerin (even though chest pain is typically treated with this medicine) could cause cardiovascular collapse
What findings indicate a patient needs aortic valve replacement?
A. Mild AS on echocardiogram and swelling of the legs
B. Moderate AS on echocardiogram, no symptoms, and no other heart problems
C. Severe AS on echocardiogram and no symptoms at rest or on exercise stress
testing
D. Severe AS on echocardiogram and shortness of breath at rest
E. Severe AS on echocardiogram, no symptoms, and a fever of 103.0°F
D. Severe AS on echocardiogram and shortness of breath at rest
