Usefulness of the Valvuloarterial Impedance to Predict Adverse

8/8/2019 Usefulness of the Valvuloarterial Impedance to Predict Adverse

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Usefulness of the Valvuloarterial Impedanceto Predict Adverse Outcome inAsymptomatic Aortic Stenosis

Zeineb Hachicha, Jean G. Dumesnil,

and Philippe PibarotJ. Am. Coll.

Cardiol. 2009;54;1003-1011


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O bjectives : This study was designed to examine theprognostic value of valvuloarterial impedance (Zva) inpatients with aortic stenosis (AS).

Background : We previously showed that the Zva issuperior to standard indexes of AS severity in estimatingthe global hemodynamic load faced by the left ventricle(LV) and predicting the occurrence of LV dysfunction.This index is calculated by dividing the estimated LVsystolic pressure (systolic arterial pressure meantransvalvular gradient) by the stroke volume indexed for the body surface area.


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Reduced arterial compliance is a frequent occurrence inpatients with degenerative aortic stenosis (AS), where itindependently contributes to increase afterload anddecrease left ventricular (LV) function .

Congenital bicuspid AS is also associated with impairedaortic elasticity, independent of stenosis severity or aortic size .Hence, the LV of AS patients often faces a double load:valvular plus arterial, and in these patients, the presenceof symptoms and occurrence of adverse events shouldlogically better correlate with the global burden faced bythe ventricle than with the transvalvular gradient and/or aortic valve area (AVA).


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To this effect, we recently proposed a new indexof global LV hemodynamic load, that is, thevalvuloarterial impedance (Zva), which iscalculated by dividing the estimated LV systolicpressure (systolic arterial pressure meantransvalvular gradient) by the stroke volumeindex (SVI) .This index, in fact, represents the cost in mm Hgfor each systemic milliliter of blood indexed for the body size pumped by the LV during systole


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M ethods

Patient population.retrospectively reviewed the clinical andechocardiographic data that were prospectively collectedin 544 asymptomatic patients ( 320 men and 224 women ; mean age 7 0 14 years ; range 21 to 98 years) with atleast a moderate AS, defined as peak aortic jet velocity

2 .5 ms 1 .The exclusion criteria were

concomitant moderate or severe aortic insufficiency or mitral valve disease, left ventricular ejection fraction(LVEF)< 50% , and the presence of symptoms atbaseline.


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C linical data. includedage, sex, history of smoking,

documented diagnosis of hypertension,hypercholesterolemia,diabetes, obesity (body mass index 30

kg/m 2 ), andcoronary heart disease ( 5 )


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Systemic arterial hemodynamics

Systemic arterial pressure was measured with the use of an arm cuff sphygmomanometer at the same time as theDoppler measurement of stroke volume (SV) wasmeasured in the left ventricular outflow tract.The ratio of SVI to brachial pulse pressure (PP) wasused as an indirect measure of total systemic arterialcompliance: SA C= SVI/PP .The systemic vascular resistance was estimated by theformula: SV R = (80 x M AP)/ CO , where M AP is the meanarterial pressure defined as diastolic pressure plus one -third of PP and CO is the cardiac output.


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Usefulness of the Valvuloarterial Impedance to Predict Adverse