Key result
Noninvasive LV elastance estimation strongly correlates with invasive calculations and detects increases in hypertension.
Why the study?
Does a noninvasive ejection P-V curve method using 3D echocardiography and carotid tonometry accurately estimate left ventricular elastance in hypertensive and normotensive subjects?
Observational (n=65)
Does a noninvasive ejection P-V curve method using 3D echocardiography and carotid tonometry accurately estimate left ventricular elastance in hypertensive and normotensive subjects?
Effect estimate: r2 = 0.92
p-value: p=<0.005
A novel noninvasive method using 3D echocardiography and carotid tonometry accurately estimates left ventricular elastance and can detect expected increases in contractility in hypertensive patients.
Supports noninvasive LV elastance estimation in hypertension; hypothesis-generating and leaves open prospective validation before clinical use.
End-systolic left ventricular (LV) elastance ( E es ) has been previously calculated and validated invasively using LV pressure-volume (P-V) loops. Noninvasive methods have been proposed, but clinical application remains complex. The aims of the present study were to 1) estimate E es according to modeling of the LV P-V curve during ejection (“ejection P-V curve” method) and validate our method with existing published LV P-V loop data and 2) test the clinical applicability of noninvasively detecting a difference in E es between normotensive and hypertensive subjects. On the basis of the ejection P-V curve and a linear relationship between elastance and time during ejection, we used a nonlinear least-squares method to fit the pressure waveform. We then computed the slope and intercept of time-varying elastance as well as the volume intercept (V 0 ). As a validation, 22 P-V loops obtained from previous invasive studies were digitized and analyzed using the ejection P-V curve method. To test clinical applicability, ejection P-V curves were obtained from 33 hypertensive subjects and 32 normotensive subjects with carotid tonometry and real-time three-dimensional echocardiography during the same procedure. A good univariate relationship ( r 2 = 0.92, P < 0.005) and good limits of agreement were found between the invasive calculation of E es and our new proposed ejection P-V curve method. In hypertensive patients, an increase in arterial elastance ( E a ) was compensated by a parallel increase in E es without change in E a / E es . In addition, the clinical reproducibility of our method was similar to that of another noninvasive method. In conclusion, E es and V 0 can be estimated noninvasively from modeling of the P-V curve during ejection. This approach was found to be reproducible and sensitive enough to detect an expected increase in LV contractility in hypertensive patients. Because of its noninvasive nature, this methodology may have clinical implications in various disease states. NEW & NOTEWORTHY The use of real-time three-dimensional echocardiography-derived left ventricular volumes in conjunction with carotid tonometry was found to be reproducible and sensitive enough to detect expected differences in left ventricular elastance in arterial hypertension. Because of its noninvasive nature, this methodology may have clinical implications in various disease states.
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Bonnet et al. (2017) conducted an observational in Arterial hypertension (n=65). Ejection P-V curve method (carotid tonometry and real-time 3D echocardiography) vs. Invasive calculation (validation) and normotensive subjects (clinical) was evaluated on Correlation between invasive calculation of Ees and the new ejection P-V curve method (r2 = 0.92, p=<0.005). Noninvasive estimation of left ventricular elastance using the ejection P-V curve method correlated strongly with invasive calculations (r2=0.92, P<0.005) and detected increases in hypertension.
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