**9. Strain imaging in low gradient severe aortic stenosis**

Several studies have characterized the LV deformation indices in patients with low gradient aortic stenosis:


**49**

*Clinical Applications of Strain Imaging in Aortic Valve Disease*

enhance risk stratification in this high-risk population.

of clinical and demographic characteristics [32].

attenuated by both hypertension and AS severity [33].

**11. Strain imaging and aortic valve surgery/intervention**

**10. Strain imaging in aortic stenosis—effects of hypertension**

incremental prognostic value beyond that obtained from rest RVLS. Thus, RVLS measurement at rest and with dobutamine stress may be helpful to

The added effect of hypertension in deformation indices abnormalities has been

• Hypertension has significant negative effect on LV mechanics in patients with aortic stenosis. Blood pressure is associated with deterioration of LV global longitudinal and circumferential strains in aortic stenosis patients independently

• In AS, both the AS severity and concomitant hypertension attenuate radial tissue Doppler imaging strain in the inferior LV wall. The subendocardial radial strain is mainly influenced by AS severity, while midmyocardial radial strain is

The contributions of LV strain analysis in the surgical or interventional manage-

• LV longitudinal systolic strain is depressed despite preserved LV ejection fraction and fractional shortening in AS. A significant association exists among natriuretic peptides, myocardial longitudinal contractility, and the degree of symptoms. Reverse LV remodeling after aortic valve replacement with regression of myocardial hypertrophy results in improvement of LV longitudinal myocardial strain and decrease of Nt-pro-BNP plasma levels. LV strain analysis has the potential to identify patients with asymptomatic AS who might benefit

from earlier surgical intervention to preserve overall LV function [34].

• Shortly after balloon valvuloplasty for severe congenital AS, there is an

attributed to residual stenosis or aortic regurgitation [36].

improvement in systolic myocardial deformation. However, two-dimensional speckle-tracking echocardiographic parameters do not return to normal at 3-year follow-up. These abnormalities in systolic deformation cannot be fully

• Marcus et al. [36] showed in 37 children that shortly after balloon valvuloplasty for severe congenital AS, there is an improvement in systolic myocardial deformation. However, two-dimensional speckle tracking echocardiography parameters do not return to normal at 3-year follow-up. These abnormalities in systolic deformation cannot be fully attributed to residual stenosis or aortic regurgitation.

• In patients with symptomatic severe aortic stenosis undergoing aortic valve replacement, reduced GLS (Particularly in the setting of normal LVEF) provides important prognostic information beyond standard risk factors [35].

ment of patients with aortic stenosis has been extensively documented. The following statements summarize the conclusions of several studies addressing the use of strain imaging as it relates to valve replacement or intervention in patients with

*DOI: http://dx.doi.org/10.5772/intechopen.93341*

defined in the following studies:

aortic stenosis.

*Advances in Complex Valvular Disease*

low gradient aortic stenosis:

fraction [27].

future adverse outcomes.

fundamental to its pathophysiology.

low LV ejection fraction, low-gradient aortic stenosis.

AS severity than subepicardial longitudinal strain while correlations between

• Compared with normal controls, severe aortic stenosis patients have impaired

Several studies have characterized the LV deformation indices in patients with

• GLS is depressed in patients with paradoxic low flow (PLF) AS. This implies that subclinical myocardial dysfunction may be more prominent in PLF AS compared with normal-flow AS and suggests the possible diagnostic and prognostic value of two-dimensional global strain in identifying PLF AS [26].

• In patients with low flow-low gradient aortic stenosis, 2-dimensional strain parameters are strong predictors of outcome. Peak longitudinal strain rate may add incremental prognostic value beyond what is obtained from N-terminal pro-B-type natriuretic peptide and peak stress left ventricular ejection

• Sato et al. [28] demonstrated in 204 patients that longitudinal LV function is severely impaired in patients with paradoxical low-flow, low-gradient (LFLPG) AS and they have a poor prognosis. GLS could stratify the high-risk group for

• Patients with paradoxical low-flow severe aortic stenosis (PLF-AS) reportedly have higher left ventricular hydraulic load and more systolic strain dysfunction than patients with normal-flow aortic stenosis. Holmes et al. [29] investigated the relationship of systolic loading and strain to PLF-AS in 120 patients. Patients with PLF-AS were found to have more valvular load, lower energy loss coefficient, more arterial load and increased systemic vascular resistance and more total hydraulic load. They concluded that Increased hydraulic load, from more severe valvular stenosis and increased vascular resistance, and longitudinal strain impairment are associated with PLF-AS and their interplay is likely

• Dahou et al. [30] examined the impact of left ventricular (LV) global longitudinal strain (GLS) measured at rest and at dobutamine stress echocardiography on the outcome of 202 patients with low LV ejection fraction and low-gradient aortic stenosis. GLS was found to be independently associated with mortality in patients with low LV ejection fraction, low-gradient aortic stenosis. Stress GLS measured during dobutamine stress echocardiography provided incremental prognostic value beyond GLS measured at rest in these patients. Hence, these authors concluded that measurement of GLS at rest and during dobutamine stress echocardiography may be helpful to enhance risk stratification in

• In patients with LF-LG AS and low LVEF, reduced right ventricular longitudinal strain (RVLS) was found by Dahou et al. [31] to be independently associated with increased risk of mortality. Furthermore, stress RVLS provided

circumferential and radial strain and AS severity are weak [24].

strain in all three layers of the LV myocardium [25].

**9. Strain imaging in low gradient severe aortic stenosis**

**48**

incremental prognostic value beyond that obtained from rest RVLS. Thus, RVLS measurement at rest and with dobutamine stress may be helpful to enhance risk stratification in this high-risk population.
