Classification of Aortic Stenosis by Flow and Gradient Patterns Provides Insights into the Pathophysiology of Disease

Abstract

Different patterns of flow and valve gradients can lead to diagnostic uncertainty about the severity of aortic stenosis (AS). Consecutive patients with severe AS (valve area <1 cm²) underwent echocardiography and computed tomography. Patients were classified into 4 groups (high-gradient/normal flow [HG_NF], high-gradient/low flow [HG_LF], low-gradient/normal flow [LG_NF], and low-gradient/low flow [LG_LF]). Low flow was defined as stroke volume index <35 mL/m² and low gradient as a mean aortic gradient <40 mm Hg. Aortic valve calcification (AVC) was calculated using the Agatston score. Of 181 patients, 56, 30, 46, and 49 had HG_NF, HG_LF, LG_NF and LG_LF with median AVC of 2048, 2015, 1366, and 1178 AU/m² (P < .0001) and valvuloarterial impedance of 4.5, 6.4, 4.2, and 5.9, respectively (P < .0001). Among those with LG_LF, AVC was lower in patients with preserved compared to reduced left ventricular ejection fraction (1018 vs 2550 AU/m²; P < .0001), but valvuloarterial impedance was similar (P = .33). The LG_LF AS with preserved ejection fraction is associated with lower AVC and may identify patients with less severe AS in association with an adaptive ventricular response to high afterload.

Keywords

aortic stenosis valve calcification echocardiography cardiac computed tomography

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References

Nkomo

Gardin

Skelton

Gottdiener

Scott

Enriquez-Sarano

. Burden of valvular heart diseases: a population-based study. Lancet. 2006;368(9540):1005–1011.

Ross

Braunwald

. Aortic stenosis. Circulation 1968;38(1 suppl):61–67.

Vahanian

Alfieri

Andreotti

. Guidelines on the management of valvular heart disease (version 2012): the joint task force on the management of valvular heart disease of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2012;33(19):2451–1496.

Monin

Quéré

Monchi

. Low-gradient aortic stenosis: operative risk stratification and predictors for long-term outcome: a multi-center study using dobutamine stress hemodynamics. Circulation. 2003;108(3):319–324.

Hachicha

Dumesnil

Bogaty

Pibarot

. Paradoxical low-flow, low-gradient severe aortic stenosis despite preserved ejection fraction is associated with higher afterload and reduced survival. Circulation. 2007;115(22):2856–2864.

Clavel

Dumesnil

Capoulade

Mathieu

Sénéchal

Pibarot

. Outcome of patients with aortic stenosis, small valve area, and low-flow, low-gradient despite preserved left ventricular ejection fraction. J Am Coll Cardiol. 2012;60(14):1259–1267.

Mehrotra

Jansen

Flynn

. Differential left ventricular remodelling and longitudinal function distinguishes low flow from normal-flow preserved ejection fraction low-gradient severe aortic stenosis. Eur Heart J. 2013;34(25):1906–1914.

Tribouilloy

Rusinaru

Maréchaux

. Low-gradient, low-flow severe aortic stenosis with preserved left ventricular ejection fraction: characteristics, outcome, and implications for surgery. J Am Coll Cardiol. 2015;65(1):55–66.

Maes

Boulif

Piérard

. Natural history of paradoxical low-gradient severe aortic stenosis. Circ Cardiovasc Imaging. 2014;7(4):714–722.

10.

Jander

Minners

Holme

. Outcome of patients with low-gradient “severe” aortic stenosis and preserved ejection fraction. Circulation. 2011;123(8):887–895.

11.

Lancellotti

Magne

Donal

. Clinical outcome in asymptomatic severe aortic stenosis: insights from the new proposed aortic stenosis grading classification. J Am Coll Cardiol. 2012;59(3):235–243.

12.

Eleid

Sorajja

Michelena

Malouf

Scott

Pellikka

. Flow-gradient patterns in severe aortic stenosis with preserved ejection fraction: clinical characteristics and predictors of survival. Circulation. 2013;128(16):1781–1789.

13.

Freeman

Otto

. Spectrum of calcific aortic valve disease: pathogenesis, disease progression, and treatment strategies. Circulation. 2005;111(24):3316–3326.

14.

Rosenhek

Binder

Porenta

. Predictors of outcome in severe, asymptomatic aortic stenosis. N Engl J Med. 2000;343(9):611–617.

15.

Messika-Zeitoun

Aubry

Detaint

. Evaluation and clinical implications of aortic valve calcification measured by electron-beam computed tomography. Circulation. 2004;110(3):356–362.

16.

Cueff

Serfaty

Cimadevilla

. Measurement of aortic valve calcification using multislice computed tomography: correlation with haemodynamic severity of aortic stenosis and clinical implication for patients with low ejection fraction. Heart. 2011;97(9):721–726.

17.

Clavel

Messika-Zeitoun

Pibarot

. The complex nature of discordant severe calcified aortic valve disease grading: new insights from combined Doppler echocardiographic and computed tomographic study. J Am Coll Cardiol. 2013;62(24):2329–2338.

18.

Lang

Badano

Mor-Avi

. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American society of echocardiography and the European association of cardiovascular imaging. Eur Heart J Cardiovasc Imaging. 2015;16( 3):233–271.

19.

Baumgartner

Hung

Bermejo

. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. Eur J Echocardiogr. 2009;10(1):1–25.

20.

Voelker

Reul

Nienhaus

. Comparison of valvular resistance, stroke work loss, and Gorlin valve area for quantification of aortic stenosis. An in vitro study in a pulsatile aortic flow model. Circulation. 1995;91(4):1196–1204.

21.

deFilippi

Willett

Brickner

. Usefulness of dobutamine echocardiography in distinguishing severe from nonsevere valvular aortic stenosis in patients with depressed left ventricular function and low transvalvular gradients. Am J Cardiol. 1995;75(2):191–194.

22.

Eleid

Nishimura

Borlaug

Sorajja

. Invasive measures of afterload in low gradient severe aortic stenosis with preserved ejection fraction. Circ Heart Fail. 2013;6(4):703–710.

23.

Kamperidis

van Rosendael

Katsanos

. Low gradient severe aortic stenosis with preserved ejection fraction: reclassification of severity by fusion of Doppler and computed tomographic data. Eur Heart J. 2015;36(31):2087–2096.