Orthostatic stress echocardiography as a useful test to measure variability of transvalvular pressure gradients in aortic stenosis

Pawel Petkow Dimitrow,Danuta Sorysz

doi:10.1186/1476-7120-11-15

Pawel Petkow Dimitrow, Danuta Sorysz

Open Access

https://doi.org/10.1186/1476-7120-11-15

Copy DOI

Abstract

The aim of the study was to assess the influence of the orthostatic stress test on changes in aortic pressure gradients in patients with aortic stenosis (AS).MethodsThe orthostatic stress test was performed in 56 AS patients. The maximum aortic gradient was compared between the supine and the upright position (using Doppler echocardiography from the apical window). The left hand of each patient was kept on top of their head for both readings. 21 patients were excluded from the study for three reasons: 1) atrial fibrillation (significant beat-to-beat variability of measured gradient), 2) suboptimal Doppler signal during the orthostatic test, and 3) aortic gradient significantly higher in suprasternal or right parasternal windows than in apical window (different direction of stenosed blood jets) in the supine examination. The last limitation (#3) is methodologically important because during the orthostatic examination, only the transapical measurement was used. We were able to analyze 35 AS patients (20 males, 15 females, mean age 74.8 ± 9.2 years).ResultsThe wide range of severity of AS was examined (maximal aortic gradient in the supine position from 30 to 146 mmHg). With regard to statistical trends, the mean value of the maximum aortic gradient significantly decreased after orthostatic stress (from 87.5 ± 28.6 to 75.8 ± 23.7 mmHg), p > 0.01). In 7 patients (increasing responders) the peak aortic gradient slightly increased during the stress test. Five of the seven only increased by a few percent. The other two patients increased by nearly 10%. In contrast, the remaining 28 AS patients’ gradient decreased by as much as 40% (decreasing responders).ConclusionsThe orthostatic position test frequently generated a decrease of “theoretically fixed at rest” valvular gradient in AS. The combination of the stiffened stenotic valve apparatus and a reduced LV preload may be responsible for this decreasing response.

Highlights

Several studies have reported the importance of upright posture during exercise in the detection of provocable or labile left ventricular outflow tract gradients (LVOTG) in hypertrophic cardiomyopathy or other obstructing conditions [1,2,3,4,5,6,7,8,9]
With regard to statistical trends, the mean value of the maximum aortic gradient significantly decreased after orthostatic stress, p > 0.01)
In 7 patients the peak aortic gradient slightly increased during the stress test

Summary

Introduction

Several studies have reported the importance of upright posture during exercise in the detection of provocable (latent) or labile left ventricular outflow tract gradients (LVOTG) in hypertrophic cardiomyopathy or other obstructing conditions [1,2,3,4,5,6,7,8,9]. Verification of LVOTG in the upright position prior to exercise is essential. As far as we are aware, the orthostatic response of valvular gradients in aortic stenosis (AS) has not been performed yet. Low-exercise (i.e. low-stress test) was proposed apart from aggressive dobutamine stimulation [11]. This examination was performed in the supine position [11]. Exercise testing should be considered only in patients with severe AS with equivocal or no symptoms and who are eligible for aortic valve replacement [12]

Objectives

Methods

Results

Discussion

Conclusion