Aortic Stenosis Flashcards
Characteristic of aortic pressure tracing in AS
1.
2.
3.
Gradients:
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2.
3.
- Presence of anacrotic notch - the aortic valve starts to open in systole but stops “short,” which impedes aortic flow
The early opening of the aortic valve corresponds to the early upstroke, whereas the early cessation of aortic opening and the slowing of flow correspond to the anacrotic notch - Slow upstroke after the anacrotic notch and peaks late (pulsus parvus and tardus)
- Reduced pulse pressure because of reduced in SV
Gradients
1. Peak to peak gradient
2. Peak instantaneous gradient
3. Mean gradient
Sudden increase in aortic systolic pressure upon removal of the LV catheter, signifying such a critical AS obstruction that a catheter placed across the valve further impedes flow (seen in case of a valve area <0.6 cm2)
Carabello’s sign
The pullback method is not reliable in case of AF, where significant beat-to-beat variability in pressure mandates simultaneous recordings.
In case of AF with AS, transaortic gradient is reduced in case of
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2.
Gradient is increased:
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2.
Transaortic pressure gradient is reduced in case of
1. inappropriate tachycardia
2. short R-R interval
Gradient is increased:
1. After a premature ventricular complex (PVC)
2. long R-R interval
Opposit occurs in MS
In LFLG AS, what principles take place in calculation of AVA
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2.
First, AVA is flow dependent (ie, reduced flow reduces the opening of a moderately stenotic valve), and second, Gorlin’s equation may be inaccurate at low flow states (ie, Gorlin’s equation is flow dependent).
3 responses in Dobutamine study in case of LFLG AS:
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2.
3.
- Truly severe AS - Stroke volume increases by >/= 20%, gradient increases to >30 mmHg, and AVA remains unchanged or increases but remains </= 1.2 cm2
- Pseudosevere AS - Stroke volume increases by >/= 20%, gradient remains </= 30 mmHg, and AVA increases to >1.2 cm2
- Poor contractile reserve (AS + LVD or AS + CMP) - Stroke volume does not significantly increase (<20%), and gradient and AVA do not significantly change
Make sure patients is not hypovolemic, hypertensive with inc SVR/afterload
Cases where Low gradient Severe AS but Normal EF is seen:
1. ____________ reduction
2. Associated ___________ valve disease that reduces the flow across the aortic valve
3. Severe _________________
- Severe preload reduction (eg, hypovolemia)
- Associated mitral valve disease that reduces the flow across the aortic valve
- Most importantly, this situation is commonly seen in case of severe systemic hypertension (HTN). Hypertensive patients may have severe AS with a paradoxically low flow and low gradient
_______________ or _________________ global LV afterload is the sum of AS and HTN
Double Load or Valvuloarterial Impedance - global LV afterload is the sum of AS and HTN
Hypertension leads to an increased total afterload, which leads to a reduced stroke volume and cardiac output even if EF is normal. Subsequently, the transvalvular gradient but also the systemic pressure are reduced and “pseudonormalization” of HTN may be seen in up to 30% of cases of high double load.
Thus, both HTN and AS appear less severe in patients with a high total afterload and a low stroke volume
Calsulcate SV and Valvuloimpedance
Systolic blood pressure + mean gradient / stroke volume index. An elevated valvuloarterial impedance (>3.5-4.5 mmHg ml/2
Patients with HTN may have significant _________________________ with reduced LV cavity size. Thus, even if EF is normal, the stroke volume may be reduced
Concentric LV hypertrophy
Hypertensive patients have increased pressure downstream of the valve, explaining the __________________ in LV-aortic gradient when aortic pressure is measured downstream of the valve rather than at the valve
Reduction in LV-aortic gradient
The true pressure gradient is the gradient between the LV and the vena contracta (echo)
Catheterization further underestimates the gradient in this case because it assesses the gradient between the LV and the aortic root beyond the vena contracta, unless the aortic catheter is placed at the coronary level.
__________________ reincrease in pressure a few centimeters downstream of the valve, at the sinotubular level
Seen in ____________ patients with _______________ aortic root
Pressure recovery
Female, narrow aortic root (<2.6-3cm)
In patients with AS, pressure (potential energy) is generated by the LV. A significant portion of this energy is lost across the narrow aortic valve orifice and becomes kinetic energy. Downstream from the valve, the flow becomes laminar again, and there may be a reincrease in pressure and in potential energy, particularly in female patients with a narrow aortic root
The true gradient is the gradient between the LV pressure and the pressure downstream of the valve
This explains why catheter-calculated orifice area tends to be higher than Doppler-calculated orifice area in individuals with valve area of 1 to 1.5 cm2
Causes of low gradient AS with normal EF
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2.
3.
4.
- Hypertension
- Hypovolemia
- Mitral regurgitation or stenosis
- Pressure recovery
Effect of pressure recovery on gradient taken by echo: ____________
Effect of hypertension on gradient taken by catheterization: ____________
- Overestimation
- Underestimation
Echo much more often __________________ AS gradient
Underestimate
10% to 15% of patients develop Doppler flow acceleration across the mid-LV and/or LVOT following AVR, along with hypotension and clinical deterioration
Caused by?
Predictors?
Prior to AVR, the high LV end-systolic pressure holds the LV and LVOT walls apart. Following relief of the aortic obstruction, the fall in end-systolic pressure narrows the mid-LV and the LVOT, unmasking a dynamic obstruction
A small LV cavity, good LV contractility, and asymmetric septal hypertrophy
Tx: Bblockers, Alpha agonist if hypotensive
Avoid inotropes, IABP
How to obtain transaortic gradient?
Simultaneous LV - aorta pressures
