Abstract 17602: Impaired Global Load-independent Left Ventricular Contractility Index Across Different Severity Of Aortic Stenosis With Preserved Left Ventricle Ejection Fraction
Introduction: Management of aortic stenosis (AS) requires a comprehensive assessment of the intrinsic cardiac contractility. Measurement of left ventricle ejection fraction (LVEF) can be misleading in AS because it is dependent on alteration in left ventricle (LV) loading condition and may not necessarily reflects the intrinsic contractile state of LV . A novel global LV contractility index, (dσ*/dt)max, measures the maximal rate of change of pressure-normalized wall stress. We sought to assess the utility of (dσ*/dt)max across different severity of AS with preserved LV ejection fraction (LVEF).
Hypothesis: Global LV contractility index declines with increasing severity of AS.
Methods: We studied 1355 consecutive patients diagnosed with isolated AS and preserved LVEF ≥ 50% (413 mild AS, 595 moderate AS, 347 severe AS) from January 2000 to December 2011. Global LV contractility index, (dσ*/dt)max is determined by [3(dV/dt)max]/2Vm, where [(dV/dt)max = LV outflow tract (LVOT) peak velocity x LVOT area, Vm = myocardial volume]. Other indices included were LV dimensions, LV structures and diastolic function.
Results: Univariate analysis is presented in Table 1. There was a decline in the global LV contractility index, (dσ*/dt)max with increasing severity of AS (mild AS: 3.57±1.21s-1, moderate AS: 3.11±1.06s-1, severe AS: 2.57±0.85s-1, p<0.001). The (dσ*/dt)max was significantly different between various groups of AS [mild AS vs. moderate AS (p<0.001), mild AS vs. severe AS (p<0.001) and moderate AS vs. severe AS (p<0.001)]. On multivariate analysis, (dσ*/dt)max and LV mass index remained statistically significant across different severity of AS (p<0.001).
Conclusions: The global LV contractility index, (dσ*/dt)max deteriorates with increasing severity of AS despite preserved LVEF. This indicates myocardial dysfunction as AS worsens. Further studies are needed to evaluate the prognostic value of this index.
Author Disclosures: H.W. Sim: None. E.Z. Boey: None. B.Q. Tan: None. N.J. Ngiam: None. W. Lin: None. W.K. Kong: None. L. Zhong: None. R.S. Tan: None. K.K. Poh: None.
- © 2016 by American Heart Association, Inc.