Comprehensive Approach to Aortic Valve Disease Flashcards
What is the primary etiology of aortic stenosis (AS) in developed countries?
Atherosclerosis-like disease
Previously thought to be degenerative, AS is now recognized as an active inflammatory process similar to coronary artery disease (CAD)
What is the similarity between the plaques found in aortic stenosis and coronary artery disease?
Initial plaque of AS resembles coronary plaque
Both conditions exhibit inflammatory features and lipid-laden cores
What role do statins play in the treatment of aortic stenosis?
Tested to retard disease progression
Trials failed due to differences in plaque mechanisms between AS and CAD
What are the histopathologic features of the aortic stenosis valve?
Inflamed with hotter areas infiltrated by lymphocytes
These features are consistent with an inflammatory process
What is a potential future pharmacologic target for aortic stenosis?
Proprotein convertase subtilisin/kexin type 9 (PCSK9)
PCSK9 is involved in the removal of LDL receptors, impacting LDL and LP(a) levels
What percentage of the US population is born with a bicuspid aortic valve?
1–2%
Bicuspid valves may lead to stenosis earlier in life due to increased shear stress
Name at least three causes of aortic stenosis.
- Calcific atherosclerotic disease
- Rheumatic heart disease
- Post radiation
Other causes include carcinoid syndrome, serotonergic drugs, and Paget’s disease
How is bicuspid aortic valve related to aortopathy?
Associated with aortic root or ascending aorta dilatation
More common with joined right and left cusps
What are the two major theories explaining aortic root dilatation in patients with bicuspid aortic valves?
- Genetic predisposition to aortic root dilatation
- Abnormal flow exiting the misshapen aortic valve
Both mechanisms may contribute to the phenomenon
What is the significance of symptoms in patients with aortic stenosis?
Presence of symptoms indicates worse prognosis
Symptomatic patients have a significantly poorer outcome compared to asymptomatic patients
What is the mean pressure gradient between the left ventricle and aorta at an aortic valve area of 1.0 cm²?
25 mmHg
This gradient increases with further stenosis
What is left ventricular hypertrophy (LVH) and how is it triggered in aortic stenosis?
Development of concentric hypertrophy due to pressure overload
This involves the addition of sarcomeres in parallel, leading to increased wall thickness
What are the potential consequences of left ventricular hypertrophy in patients with aortic stenosis?
- Angina
- Heart failure
- Syncope
LVH contributes to impaired coronary blood flow reserve and diastolic filling
What factors contribute to the impaired coronary blood flow reserve in LVH?
- Diminished capillary ingrowth
- Increased LV filling pressure
These factors reduce the pressure gradient for coronary flow
What are the stages of aortic stenosis according to the ACC/AHA Guidelines?
- 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
What defines ‘severe’ aortic stenosis according to current guidelines?
- 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
What is the impact of earlier detection and treatment of aortic stenosis?
Patients are older and more prone to hypertension
This shift affects the treatment approach, focusing on both the stenotic valve and systemic hypertension
What is aortic stenosis (AS)?
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.
What does the Gorlin formula predict in patients with aortic stenosis?
The Gorlin formula predicts the expected valve area based on the pressure gradient and flow across the valve.
In what percentage of patients is there a discordance between valve area and gradient predictions?
30% of patients.
What should be done for asymptomatic patients with severe AS and LV dysfunction?
They require aortic valve replacement (AVR) even though they are asymptomatic.
What defines LV dysfunction in aortic stenosis?
LV dysfunction may be defined by an ejection fraction (EF) falling below 60%.
What is the prognosis for symptomatic patients with severe AS without AVR?
The prognosis is dire.
What is the average increase in jet velocity for aortic stenosis patients per year?
0.2–0.4 m/s/year.
What does a murmur of aortic stenosis sound like?
A raspy systolic ejection murmur that radiates to the neck.
What phenomenon may mislead an examiner during a physical exam of AS?
Gallavardin’s phenomenon.
What imaging method is the mainstay for diagnosing aortic stenosis?
Echocardiography.
True or False: The intensity of the murmur in aortic stenosis is directly related to disease severity.
False.
How is the pressure gradient across the aortic valve calculated?
Using the modified Bernoulli equation: g = 4V².
What is the significance of measuring the aortic outflow tract (LVOT) diameter accurately?
Accurate measurement is crucial for deriving the aortic valve area and assessing the severity of aortic stenosis.
What are the challenges when using the continuity equation for assessment of aortic stenosis?
Underestimating or overestimating the severity of aortic stenosis due to inaccurate LVOT measurements.
Fill in the blank: The maximum aortic velocity can be grossly underestimated if the continuous Doppler beam is not aligned _______.
[parallel or near parallel to the stenotic jet].
What does the presence of LVH on an EKG indicate?
It may indicate left ventricular hypertrophy due to aortic stenosis.
What is the recommended frequency of echocardiographic observation for patients with jet velocity >3.0 m/s?
Yearly.
What is the expected decrease in aortic valve area (AVA) per year in patients with aortic stenosis?
0.1–0.2 cm²/year.
What is the typical carotid pulse tracing in patients with aortic stenosis?
Reduced volume and delayed timing (parvus et tardus).
What is the impact of body habitus on echocardiographic imaging?
Poor acoustic windows may hinder accurate imaging.
What imaging modality can be used for estimating the LVOT diameter when echocardiography is challenging?
Transesophageal echocardiography (TEE).
What does the presence of calcification in the aortic valve correlate with?
The severity of aortic stenosis.
How should LVOT diameter be measured to ensure accuracy?
Using the ‘ZOOM’ view and measuring at the hinge points in mid-systole.
What happens to the aortic valve in severe aortic stenosis?
It becomes heavily calcified and nearly immobile.
What can cause acoustic shadowing during imaging of the aortic valve?
Calcified aortic valve and aortic root.
What is a potential pitfall when assessing aortic stenosis severity?
Inaccurate alignment of the Doppler beam to the stenotic jet.
What imaging method can be used for estimation of the LVOT diameter?
Transesophageal echocardiography (TEE)
TEE is a valuable tool for assessing cardiac structures and function.
What can cause inaccurate measurement of the LVOT?
Acoustic shadowing from calcified aortic valve and aortic root
This phenomenon occurs when sound waves are blocked by dense structures, leading to measurement errors.
What is the correlation between aortic valve calcification and aortic stenosis (AS) severity?
The degree of calcification correlates with AS severity
Multidetector CT scanning can be used to measure valve calcification.
What is the formula used to define valve area (A) in both noninvasive and invasive techniques?
A = F/V where F = flow and V = flow velocity
This principle is fundamental to assessing valve function.
How is velocity measured in echocardiography?
Velocity is measured directly
This allows for real-time assessment of blood flow across heart valves.
What is Torricelli’s equation used for in invasive hemodynamic evaluation?
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.
What is the Gorlin formula used for?
AVA = F/2√gh where AVA is aortic valve area
It utilizes flow measurement and pressure gradients to determine valve area.
What is the significance of pulse delay in recording from the femoral artery?
It makes recording inaccurate and should not be used
Accurate pressure recording is crucial for determining hemodynamics.
What is the primary treatment for aortic stenosis (AS)?
Aortic valve replacement (AVR)
No medical therapy has shown to alter the natural history of AS.
What should be the approach for antihypertensive agents in AS patients?
Start low and go slow
This is to prevent hypotension due to fixed valve obstruction.
What is the mortality rate for untreated symptomatic AS?
About 2% per month or 75% at 3 years
This highlights the urgency for surgical intervention in symptomatic patients.
What is the prognosis for patients with symptomatic AS after AVR?
Restores life expectancy to or toward that of an unaffected population
AVR significantly improves survival compared to no therapy.
What is the risk of sudden death in truly asymptomatic patients with severe AS?
About 1% per year
This risk is similar to the operative mortality rate in experienced centers.
What role does exercise testing play in managing asymptomatic severe AS?
Establishes objective evidence of dyspnea on exertion and hemodynamic response
Exercise testing can help identify patients who may need early AVR.
What is the impact of transaortic jet velocity on patients with AS?
Higher jet velocity increases the likelihood of symptoms or death
Jet velocity exceeding 5 m/s indicates a particularly ominous prognosis.
What biomarkers are important in assessing asymptomatic AS patients?
Increased levels of brain natriuretic hormone (BNP) and troponin
Elevated BNP may help in timing AVR.
What is the consequence of bypass surgery leaving moderate AS untreated?
Symptomatic AS may develop in 2–3 years, necessitating AVR during a second operation
Early intervention is often recommended to avoid complications.
What are the two definitive therapies for AS?
- Surgical Aortic Valve Replacement (SAVR)
- Transcatheter Aortic Valve Replacement (TAVR)
The choice of procedure depends on various patient factors.
What factors influence the decision-making process for valve replacement?
- 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.
