Clinical Investigation
Valvular Heart Disease
Deterioration of Myocardial Function in Paradoxical Low-Flow Severe Aortic Stenosis: Two-Dimensional Strain Analysis

https://doi.org/10.1016/j.echo.2011.05.003Get rights and content

Background

The diagnosis and management of paradoxical low-flow (PLF) aortic stenosis (AS) is challenging in clinical practice. In addition, its pathophysiology has not been fully understood. The aim of this study was to test the hypothesis that left ventricular (LV) myocardial function is deteriorated in PLF AS and that it is closely related to global LV afterload.

Methods

Echocardiographic data from 103 patients with severe AS (aortic valve area < 1.0 cm2) with normal LV ejection fractions were prospectively collected. Global longitudinal and circumferential myocardial strain was analyzed using two-dimensional speckle-tracking imaging. PLF AS was defined as a stroke volume index < 35 mL/m2.

Results

Sixteen patients were classified as having PLF AS. Compared with those with normal-flow AS, patients with PLF AS were more likely to have worse functional status (mean New York Heart Association functional class, 2.38 ± 0.70 vs 1.96 ± 0.62; P = .02), worse global longitudinal strain (GLS) (−12.6 ± 4.4% vs −16.4 ± 4.0%, P < .01), lower aortic valve area (0.53 ± 0.15 vs 0.78 ± 0.19 cm2, P < .01), and higher valvuloarterial impedance (5.62 ± 1.33 vs 3.65 ± 0.83 mm Hg · m2/mL, P < .01). GLS showed a significant negative linear relationship with stroke volume index (r = −0.324, P = .001) and a positive relationship with E/E′ ratio (r = 0.367, P < .001). Multivariate analysis showed that age (β = 0.08, P = .07) and valvuloarterial impedance (β = 1.54, P < .01) were significant predictors of GLS.

Conclusions

GLS is depressed in patients with 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. In addition, global LV afterload is an important determinant of myocardial dysfunction in patients with severe AS.

Section snippets

Patient Population

A total of 103 patients with severe AS and preserved LV ejection fractions (LVEFs; >50%) per the definition of AVA < 1.0 cm2 in the American College of Cardiology and American Heart Association guidelines were enrolled in the study irrespective of symptom status. Patients with significant concomitant valvular heart disease of grade ≥3 other than AS (i.e., concomitant aortic regurgitation or mitral, tricuspid, or pulmonic valve disease; significant regional wall motion abnormality; or history of

Results

Among 103 patients, 16 were classified as having PLF AS. Patients with PLF AS tended to have larger body surface areas, were less likely to have hypertension, and were more likely to have atrial fibrillation (Table 1). Interestingly, patients with PLF AS also tended to have worse functional status compared with those with NF AS (mean New York Heart Association functional capacity, 1.96 ± 0.62 for NF AS vs 2.38 ± 0.70 for PLF AS; P = .02).

Compared with the NF AS group, LVEFs were significantly

Discussion

The main findings of this study are that (1) patients with PLF AS showed significantly impaired myocardial function despite preserved LVEFs, as verified by GLS with the use of 2D speckle-tracking imaging; (2) global LV afterload, represented by Zva, may be a significant determinant of subclinical LV dysfunction in severe AS; and (3) GLS might be useful to corroborate the diagnosis PLF AS and also to predict the prognosis of severe AS.

Conclusions

GLS measured by 2D speckle-tracking imaging is depressed in patients with PLF AS. This implies that subclinical myocardial dysfunction is evident in these patients. It also suggests the possible diagnostic value of 2D global strain in PLF AS. In addition, global LV afterload is an important determinant of myocardial dysfunction in patients with severe AS.

Acknowledgments

We thank Seon-Jin Kim, RN, for her assistance in gathering the echocardiographic data and Ha-Young Joo, RN, for her help in management of the database. We are also indebted to the helpful assistance in statistical analysis from the Medical Research Collaborating Center, Seoul National University Hospital.

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    This study was supported by grants A100200 and A090458 from the Korean Health Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea.

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