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[Doppler echocardiographic evaluation of left ventricular wall stress in aortic stenosis]
D Raguin1, C Tribouilloy, A Py
1Service de cardiologie, CHU Amiens Sud.
Insights
This study validates a non-invasive method to measure left ventricular wall stress in aortic stenosis patients. Symptomatic patients showed significantly elevated wall stress, unlike asymptomatic ones, aiding in assessing cardiac adaptation.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Imaging
Background:
- Left ventricular wall stress measurement is crucial for understanding cardiac adaptation in conditions like hypertension and aortic stenosis.
- Calculating wall stress in aortic stenosis is challenging due to the ventriculo-aortic pressure gradient, limiting its use in clinical practice.
- Previous methods for assessing left ventricular pressure in aortic stenosis required invasive catheterization.
Purpose of the Study:
- To validate a non-invasive method for calculating peak systolic left ventricular pressure in aortic stenosis.
- To prospectively measure meridian and circumferential wall stress in patients with aortic stenosis.
- To compare wall stress values between normal subjects, asymptomatic aortic stenosis patients, and symptomatic aortic stenosis patients.
Main Methods:
- A preliminary study validated peak systolic left ventricular pressure by comparing non-invasive calculations with invasive catheterization data in 21 aortic stenosis patients.
- Prospective measurement of meridian and circumferential wall stress using Doppler echocardiography in 35 aortic stenosis patients (29 symptomatic, 6 asymptomatic).
- Comparison of wall stress values with those from 21 normal subjects.
Main Results:
- The non-invasive method for calculating left ventricular pressure was validated against invasive measurements.
- Asymptomatic aortic stenosis patients exhibited normal wall stress values (136 ± 28 and 303 ± 41 x 10^3 dynes/cm²), comparable to normal subjects (151 ± 22 and 311 ± 37 x 10^3 dynes/cm²).
- Symptomatic aortic stenosis patients demonstrated significantly elevated wall stress (210 ± 55 and 437 ± 94 x 10^3 dynes/cm², p < 0.0001), with only 6 patients having normal stress levels.
Conclusions:
- Non-invasive measurement of left ventricular wall stress using Doppler echocardiography is feasible and comparable to invasive methods.
- This technique can effectively evaluate left ventricular adaptation in aortic stenosis, particularly in severe cases.
- It is valuable for identifying patients with abnormal geometric remodeling, such as dilatation or inadequate hypertrophy, in the presence of aortic stenosis.
Abstract:
The measurement of wall stress allows study of morphological adaptation of the left ventricle, especially in conditions associated with symmetric hypertrophy (hypertension, aortic stenosis). The calculation is performed in hypertensive heart disease but not in aortic stenosis because of the ventriculo-aortic pressure gradient. In a preliminary study, the authors validated the peak systolic left ventricular pressure calculated by adding the systolic brachial artery pressure to the maximal transvalvular pressure gradient by comparing the value with that obtained by catheterization in 21 patients with aortic stenosis. The second phase of the study was to measure meridian and circumferential wall stress prospectively in 35 patients with aortic stenosis (29 symptomatic, 6 asymptomatic) and to compare the results with those observed in 21 normal subjects. In the latter group, the values were 151 +/- 22 and 311 +/- 37 10(3) dynes/cm2 respectively, whereas in asymptomatic aortic stenosis the stresses were 136 +/- 28 and 303 +/- 41 10(3) dynes/cm2 respectively (NS) and in symptomatic aortic stenosis 210 +/- 55 and 437 +/- 94 10(3) dynes/cm2 respectively (p < 0.0001). None of the cases of asymptomatic aortic stenosis had raised wall stress values whereas only 6 symptomatic aortic stenosis patients had normal wall stress. The values of wall stress obtained using the method proposed were comparable to those reported by other authors with invasive investigations. Non-invasive measurement of wall stress by Doppler echocardiography may be proposed as a method of evaluation of left ventricular adaptation, especially in severe stenosis and in patients with a patent geometric abnormality (abnormal dilatation or even an inadequately hypertrophied wall).