What is normal pressure gradient across mitral valve?
| Normal | Aortic Valve |
|---|---|
| Mitral Valve | Aortic Valve Mean Gradient |
| Normal Area 4.0-6.0 cm2 Mild Stenosis 1.5-2.5 cm2 Moderate Stenosis 1.5-1.5 cm2 Severe Stenosis < 1.0 cm2 | Normal Gradient < 5 mmHg Mild Stenosis 5-25 mmHg Moderate Stenosis 25-50 mmHg Severe Stenosis >50 mmHg |
| Mitral Valve Mean Gradient | Aortic Valve Peak Gradient |
How do you quantify mitral valve stenosis?
Two major factors determine the severity of mitral stenosis:the size of the mitral orifice during diastole (mitral valve area) and the magnitude of the gradients across the valve. The mitral vale area (MVA) can be determined with 2D echo (planimetry and by Doppler techniques – the pressure half time method).
How is PHT measured?
The time from the Vmax to the velocity equal to Vmax divided by 1.4 is the pressure half time. (Vmax / 1.4 is equivalent to the half pressure). 220 divided by the PHT is the mitral valve area.
What is pressure gradient echo?
The mean pressure gradient is the average instantaneous gradient across the valve during the entire systolic ejection period. The peak velocity and mean pressure gradient are strong predictors of clinical outcome.
What is Ava on Echo?
Echocardiographic assessment of the severity of aortic valve stenosis (AS) usually relies on peak velocity, mean pressure gradient (MPG) and aortic valve area (AVA), which should ideally be concordant. In 20%-30% of patients, these parameters are discordant (usually AVA <1 cm² and MPG <40 mmHg).
What is the mitral valve gradient?
Mitral valve areas less than 2 square centimeters causes an impediment to the blood flow from the left atrium into the left ventricle. This creates a pressure gradient across the mitral valve. As the gradient across the mitral valve increases, the left ventricle requires the atrial kick to fill with blood.
What is MVA PHT?
Pressure half-time (PHT) is defined as the time interval in milliseconds between the maximum mitral gradient in early diastole and the time point where the gradient is half the maximum initial value.
How is the valve area of a mitral valve measured?
The valve area is calculated using the equation, MVA = 220/P1/2 where MVA = MV area and P1/2 = pressure half-time (Figs. 9 and 10). This method correlates well with the invasive measurement of MVA. The concept behind the P1/2 method is as follows: the LV fills when blood from the LA crosses the MV during diastole.
What is the pressure half time for mitral stenosis?
According to this principle, Fig. 10. Pressure half-time (PHT). Mitral stenosis can then be categorized as mild, moderate, or severe as shown. The PHT in this patient measured 187 ms—indicating moderate mitral stenosis. Pressure Half-Time Method: Pitfalls and Caveats
How to calculate valve area by pressure half time?
Pressure Half-Time (P1/2) The P1/2 is the time it takes for the pressure gradient across the MV to decrease by half (Fig. 8). The valve area is calculated using the equation, MVA = 220/P1/2 where MVA = MV area and P1/2 = pressure half-time (Figs.
What are the gradients in mitral valve stenosis?
Continuous-wave Doppler patterns in a patient with severe mitral stenosis. Atrial fibrillation is present and is reflected in marked variation in the tracings as shown in A and B (mean gradient approx 12 mmHg). In such patients, gradients should be averaged over 5-10 cardiac cycles.