Comprehensive Approach to Aortic Valve Disease Flashcards

1
Q

What is the primary etiology of aortic stenosis (AS) in developed countries?

A

Atherosclerosis-like disease

Previously thought to be degenerative, AS is now recognized as an active inflammatory process similar to coronary artery disease (CAD)

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2
Q

What is the similarity between the plaques found in aortic stenosis and coronary artery disease?

A

Initial plaque of AS resembles coronary plaque

Both conditions exhibit inflammatory features and lipid-laden cores

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3
Q

What role do statins play in the treatment of aortic stenosis?

A

Tested to retard disease progression

Trials failed due to differences in plaque mechanisms between AS and CAD

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4
Q

What are the histopathologic features of the aortic stenosis valve?

A

Inflamed with hotter areas infiltrated by lymphocytes

These features are consistent with an inflammatory process

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5
Q

What is a potential future pharmacologic target for aortic stenosis?

A

Proprotein convertase subtilisin/kexin type 9 (PCSK9)

PCSK9 is involved in the removal of LDL receptors, impacting LDL and LP(a) levels

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6
Q

What percentage of the US population is born with a bicuspid aortic valve?

A

1–2%

Bicuspid valves may lead to stenosis earlier in life due to increased shear stress

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7
Q

Name at least three causes of aortic stenosis.

A
  • Calcific atherosclerotic disease
  • Rheumatic heart disease
  • Post radiation

Other causes include carcinoid syndrome, serotonergic drugs, and Paget’s disease

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8
Q

How is bicuspid aortic valve related to aortopathy?

A

Associated with aortic root or ascending aorta dilatation

More common with joined right and left cusps

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9
Q

What are the two major theories explaining aortic root dilatation in patients with bicuspid aortic valves?

A
  • Genetic predisposition to aortic root dilatation
  • Abnormal flow exiting the misshapen aortic valve

Both mechanisms may contribute to the phenomenon

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10
Q

What is the significance of symptoms in patients with aortic stenosis?

A

Presence of symptoms indicates worse prognosis

Symptomatic patients have a significantly poorer outcome compared to asymptomatic patients

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11
Q

What is the mean pressure gradient between the left ventricle and aorta at an aortic valve area of 1.0 cm²?

A

25 mmHg

This gradient increases with further stenosis

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12
Q

What is left ventricular hypertrophy (LVH) and how is it triggered in aortic stenosis?

A

Development of concentric hypertrophy due to pressure overload

This involves the addition of sarcomeres in parallel, leading to increased wall thickness

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13
Q

What are the potential consequences of left ventricular hypertrophy in patients with aortic stenosis?

A
  • Angina
  • Heart failure
  • Syncope

LVH contributes to impaired coronary blood flow reserve and diastolic filling

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14
Q

What factors contribute to the impaired coronary blood flow reserve in LVH?

A
  • Diminished capillary ingrowth
  • Increased LV filling pressure

These factors reduce the pressure gradient for coronary flow

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15
Q

What are the stages of aortic stenosis according to the ACC/AHA Guidelines?

A
  • Stage A: At risk for AS
  • Stage B: Progressive AS
  • Stage C: Asymptomatic severe AS
  • Stage D: Symptomatic severe AS

Each stage reflects different clinical presentations and severity

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16
Q

What defines ‘severe’ aortic stenosis according to current guidelines?

A
  • Aortic valve area of ≤1.0 cm²
  • Peak transaortic jet velocity of ≥4.0 m/s
  • Mean aortic gradient of ≥40 mmHg

Definitions may show internal inconsistencies among patients

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17
Q

What is the impact of earlier detection and treatment of aortic stenosis?

A

Patients are older and more prone to hypertension

This shift affects the treatment approach, focusing on both the stenotic valve and systemic hypertension

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18
Q

What is aortic stenosis (AS)?

A

Aortic stenosis is a condition characterized by the narrowing of the aortic valve opening, leading to reduced blood flow from the heart to the aorta.

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19
Q

What does the Gorlin formula predict in patients with aortic stenosis?

A

The Gorlin formula predicts the expected valve area based on the pressure gradient and flow across the valve.

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20
Q

In what percentage of patients is there a discordance between valve area and gradient predictions?

A

30% of patients.

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21
Q

What should be done for asymptomatic patients with severe AS and LV dysfunction?

A

They require aortic valve replacement (AVR) even though they are asymptomatic.

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22
Q

What defines LV dysfunction in aortic stenosis?

A

LV dysfunction may be defined by an ejection fraction (EF) falling below 60%.

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23
Q

What is the prognosis for symptomatic patients with severe AS without AVR?

A

The prognosis is dire.

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24
Q

What is the average increase in jet velocity for aortic stenosis patients per year?

A

0.2–0.4 m/s/year.

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25
Q

What does a murmur of aortic stenosis sound like?

A

A raspy systolic ejection murmur that radiates to the neck.

26
Q

What phenomenon may mislead an examiner during a physical exam of AS?

A

Gallavardin’s phenomenon.

27
Q

What imaging method is the mainstay for diagnosing aortic stenosis?

A

Echocardiography.

28
Q

True or False: The intensity of the murmur in aortic stenosis is directly related to disease severity.

A

False.

29
Q

How is the pressure gradient across the aortic valve calculated?

A

Using the modified Bernoulli equation: g = 4V².

30
Q

What is the significance of measuring the aortic outflow tract (LVOT) diameter accurately?

A

Accurate measurement is crucial for deriving the aortic valve area and assessing the severity of aortic stenosis.

31
Q

What are the challenges when using the continuity equation for assessment of aortic stenosis?

A

Underestimating or overestimating the severity of aortic stenosis due to inaccurate LVOT measurements.

32
Q

Fill in the blank: The maximum aortic velocity can be grossly underestimated if the continuous Doppler beam is not aligned _______.

A

[parallel or near parallel to the stenotic jet].

33
Q

What does the presence of LVH on an EKG indicate?

A

It may indicate left ventricular hypertrophy due to aortic stenosis.

34
Q

What is the recommended frequency of echocardiographic observation for patients with jet velocity >3.0 m/s?

A

Yearly.

35
Q

What is the expected decrease in aortic valve area (AVA) per year in patients with aortic stenosis?

A

0.1–0.2 cm²/year.

36
Q

What is the typical carotid pulse tracing in patients with aortic stenosis?

A

Reduced volume and delayed timing (parvus et tardus).

37
Q

What is the impact of body habitus on echocardiographic imaging?

A

Poor acoustic windows may hinder accurate imaging.

38
Q

What imaging modality can be used for estimating the LVOT diameter when echocardiography is challenging?

A

Transesophageal echocardiography (TEE).

39
Q

What does the presence of calcification in the aortic valve correlate with?

A

The severity of aortic stenosis.

40
Q

How should LVOT diameter be measured to ensure accuracy?

A

Using the ‘ZOOM’ view and measuring at the hinge points in mid-systole.

41
Q

What happens to the aortic valve in severe aortic stenosis?

A

It becomes heavily calcified and nearly immobile.

42
Q

What can cause acoustic shadowing during imaging of the aortic valve?

A

Calcified aortic valve and aortic root.

43
Q

What is a potential pitfall when assessing aortic stenosis severity?

A

Inaccurate alignment of the Doppler beam to the stenotic jet.

44
Q

What imaging method can be used for estimation of the LVOT diameter?

A

Transesophageal echocardiography (TEE)

TEE is a valuable tool for assessing cardiac structures and function.

45
Q

What can cause inaccurate measurement of the LVOT?

A

Acoustic shadowing from calcified aortic valve and aortic root

This phenomenon occurs when sound waves are blocked by dense structures, leading to measurement errors.

46
Q

What is the correlation between aortic valve calcification and aortic stenosis (AS) severity?

A

The degree of calcification correlates with AS severity

Multidetector CT scanning can be used to measure valve calcification.

47
Q

What is the formula used to define valve area (A) in both noninvasive and invasive techniques?

A

A = F/V where F = flow and V = flow velocity

This principle is fundamental to assessing valve function.

48
Q

How is velocity measured in echocardiography?

A

Velocity is measured directly

This allows for real-time assessment of blood flow across heart valves.

49
Q

What is Torricelli’s equation used for in invasive hemodynamic evaluation?

A

v = 2√gh where g is the velocity due to gravity and h is the mean pressure gradient

This equation helps calculate flow velocity based on pressure differences.

50
Q

What is the Gorlin formula used for?

A

AVA = F/2√gh where AVA is aortic valve area

It utilizes flow measurement and pressure gradients to determine valve area.

51
Q

What is the significance of pulse delay in recording from the femoral artery?

A

It makes recording inaccurate and should not be used

Accurate pressure recording is crucial for determining hemodynamics.

52
Q

What is the primary treatment for aortic stenosis (AS)?

A

Aortic valve replacement (AVR)

No medical therapy has shown to alter the natural history of AS.

53
Q

What should be the approach for antihypertensive agents in AS patients?

A

Start low and go slow

This is to prevent hypotension due to fixed valve obstruction.

54
Q

What is the mortality rate for untreated symptomatic AS?

A

About 2% per month or 75% at 3 years

This highlights the urgency for surgical intervention in symptomatic patients.

55
Q

What is the prognosis for patients with symptomatic AS after AVR?

A

Restores life expectancy to or toward that of an unaffected population

AVR significantly improves survival compared to no therapy.

56
Q

What is the risk of sudden death in truly asymptomatic patients with severe AS?

A

About 1% per year

This risk is similar to the operative mortality rate in experienced centers.

57
Q

What role does exercise testing play in managing asymptomatic severe AS?

A

Establishes objective evidence of dyspnea on exertion and hemodynamic response

Exercise testing can help identify patients who may need early AVR.

58
Q

What is the impact of transaortic jet velocity on patients with AS?

A

Higher jet velocity increases the likelihood of symptoms or death

Jet velocity exceeding 5 m/s indicates a particularly ominous prognosis.

59
Q

What biomarkers are important in assessing asymptomatic AS patients?

A

Increased levels of brain natriuretic hormone (BNP) and troponin

Elevated BNP may help in timing AVR.

60
Q

What is the consequence of bypass surgery leaving moderate AS untreated?

A

Symptomatic AS may develop in 2–3 years, necessitating AVR during a second operation

Early intervention is often recommended to avoid complications.

61
Q

What are the two definitive therapies for AS?

A
  • Surgical Aortic Valve Replacement (SAVR)
  • Transcatheter Aortic Valve Replacement (TAVR)

The choice of procedure depends on various patient factors.

62
Q

What factors influence the decision-making process for valve replacement?

A
  • LV function
  • Need for other cardiac procedures
  • Comorbidities
  • Surgical history
  • Age
  • Patient preference
  • Social considerations
  • Risk calculated from the STS database

The Heart Team assesses these variables to determine the best approach.