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Diagnostic accuracy of continuous wave Doppler echocardiography in severe aortic stenosis in the elderly
M Nitta1, T Takamoto, K Taniguchi
1Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
Insights
Continuous wave Doppler echocardiography accurately assesses aortic stenosis (AS) severity. However, low Doppler gradients may underestimate severe AS in patients with poor left ventricular function.
Area of Science:
- Cardiovascular Medicine
- Echocardiography
- Hemodynamics
Background:
- Aortic stenosis (AS) is a significant valvular heart disease.
- Accurate assessment of AS severity is crucial for patient management.
- Continuous wave (CW) Doppler echocardiography is a primary tool for evaluating AS hemodynamics.
Purpose of the Study:
- To evaluate the relationship between Doppler-derived and directly measured pressure gradients in aortic stenosis.
- To determine the accuracy of CW Doppler echocardiography in detecting severe AS.
- To identify factors contributing to underestimation of AS severity by Doppler methods.
Main Methods:
- Forty-four male patients with aortic stenosis were studied.
- Conventional hemodynamic measurements and CW Doppler echocardiography were performed.
- Analysis included correlation of Doppler mean gradients with direct mean pressure gradients and assessment of sensitivity and specificity for severe AS detection.
Main Results:
- A strong correlation (r=0.88) was found between Doppler and direct mean pressure gradients.
- A Doppler gradient ≥ 40 mmHg showed 67% sensitivity and 95% specificity for severe AS (Aortic Valve Area ≤ 1.0 cm²).
- Severe AS with low Doppler gradients (< 40 mmHg) was associated with impaired left ventricular function (low cardiac output, abnormal PEP/LVET ratio).
Conclusions:
- CW Doppler echocardiography is reliable for assessing AS severity in most patients.
- In patients with severe AS and low Doppler gradients, impaired left ventricular function may lead to underestimation of stenosis severity.
- Low stroke volume (≤ 60 ml/beat) and elevated PEP/LVET x HR (> 26) can identify patients where Doppler may significantly underestimate aortic stenosis severity.
Abstract:
Forty-four male patients (mean age 63.6 years) with aortic stenosis (AS) were evaluated by conventional hemodynamic methods and continuous wave (CW) Doppler echocardiography. The relationship between Doppler mean gradients and direct mean pressure gradients in all patients was significant, with an r value of 0.88. Sixteen of 17 patients with a mean Doppler gradient greater than or equal to 40 mmHg had severe AS (AVA less than or equal to 1.0 cm2). Twenty-seven patients had a Doppler gradient less than 40 mmHg, and 8 of these patients had severe AS (AVA less than or equal to 1.0 cm2). The sensitivity and specificity of a Doppler gradient greater than or equal to 40 mmHg in detecting severe AS were, therefore, 67% and 95%, respectively. Thirty-three percent (8/24) of patients with severe AS and low Doppler gradients (less than 40 mmHg) had evidence of poor left ventricular function, evidenced by a lower cardiac output, a higher heart rate and an abnormal PEP/LVET ratio compared to the other patients. Thus, the presence of a low stroke volume less than or equal to 60 ml/beat and PEP/LVET x HR greater than 26 is of value in identifying patients where the Doppler is likely to significantly underestimate the degree of aortic stenosis.