Doppler Stress Echo Protocols
When conducting a stress test that was ordered to evaluate mild aortic stenosis in a symptomatic patient, what should you evaluate at peak stress?
It is important to evaluate the aortic valve at peak stress and the function images after.
There will be an increase in ____________ in patients that have mild mitral stenosis with exercise.
Mean gradient
Low dobutamine Doppler stress test echo is recommended for patients with an AVA that is _________ cm^2.
1 cm^2 and are asymptomatic
When evaluating for viability, we are assessing for what two types of myocardium?
Hibernating and stunned myocardium
What is the prognosis of surgery for patients that get placed in category 3 of aortic stenosis?
Poor prognosis due to ischemic cardiomyopathy (not viable)
When evaluating mitral stenosis you should do what to the VTI, PHT, and TR measurements?
Average 3-5 beats
When is dobutamine not recommended to be used with mitral stenosis patients?
If an elevated PASP could be the reason for symptoms. Dobutamine will reduce the pulmonary vascular resistance and give an inaccurate PASP value.
A drop in systolic pressure of _______ mmHg is an indication to end a Doppler stress test?
A drop in blood pressure of greater than or equal to 20 mmHg
What is considered a biphasic response?
Improvement at low dose and decreased function at peak and post stress.
What will we see in a patient that gets placed in category 2 of aortic stenosis?
Category 2: Dilated cardiomyopathy
left ventricular function increase, increase stroke volume that leads to an increase in true valve area
When evaluating for aortic stenosis, which LVOT diameter will be used to calculate peak calculations, and what are we calculating for?
Resting LVOT diameter to calculate the AVA, SV and CO
An increase of _________ mmHg in systolic pulmonary artery pressure is considered significant for mitral stenosis.
> 60 mmHg
What are the characteristics of a low flow, low gradient aortic stenosis?
The valve seems severely calcified, valve area is reduced, left ventricular ejection fraction is reduced, mean gradient is lower than expected (<40 mmHg) for severe AS and low stroke volume (<35 mL/m2)
Hibernating myocardium is indicative of which type of viability response?
Biphasic
What will we see in a patient that gets placed in category 3 of severe aortic stenosis?
Category 3:
No change in valve area, no change in left ventricule ejection fraction, stroke volume does not increase.
What are some contraindications to conducting a Doppler stress echo for aortic stenosis?
1. Mean gradient greater or equal to 40 mmHg
2. Ascending aorta > 4.5 cm
3. Patient has AAA
An increase of ________ mmHg in mean pressure gradient is considered significant for mitral stenosis.
> 15 mmHg
What are the characteristics for normal flow, low gradient aortic stenosis?
Reduced aortic valve area, mean gradient < 30 mmHg, normal left ventricular ejection fraction, normal stroke volume
Why is a viability test conducted and what effect does Dobutamine have on myocardium?
To assess if patients will benefit from revascularization. Dobutamine will increase inotropic function of the heart with little increase in oxygen demand therefore increasing function.
True or false; a hypertrophied left ventricle could cause a normal flow, low gradient aortic stenosis?
True, this is due to a small left ventricle with decreased volume and normal ejection fraction.
What is considered a significant obstruction with HOCM patients, what can the obstruction cause?
greater than or equal to 50 mmHg and it can cause a drop of blood pressure and sudden death.
What will we see in a positive Doppler stress test with mitral stenosis?
Patient may develop dyspnea, have an increase in PASP, decrease in MVA with exercise
What will we see in a patient that gets placed in category 1 of aortic stenosis that indicates patient should benefit from surgical repair?
Category 1: Severe aortic stenosis with viability
Valve area does not change, improved left ventricular function, increase in stroke volume.
True or false
Initial stunned myocardium will likely be due to severe CAD.
False, stunned myocardium usually presents with acute coronary syndrome. The coronary arteries will appear clear. While in hibernating myocardium, patient will present with chronic CAD.
What are the parameters that will indicate diastolic dysfunction with Doppler stress test?
E/e' >14
Septal <7 cm/s
Lateral <10 cm/sec
Tricuspid regurgitation > 2.8 m/s