Abstract 11870: Noninvasive Evaluation of Impact of Pressure Overload on Left Ventricular Relaxation and Stiffness in Patients With Normal Ejection Fraction by Speckle Tracking Echocardiography: Validation and Clinical Study.

Introduction: We reported that pulmonary capillary wedge pressure (ePCWP) and time constant of left ventricular (LV) pressure decline (eTau) are noninvasively estimated by speckle tracking echocardiography (STE). LV camber stiffness (e-c stiffness) may be estimated with the use of 2 diastolic pressure-volume coordinates: the end-diastolic pressure (EDP) and volume and the pressure and volume at the time of minimum diastolic pressure (mP). Myocardial stiffness (e-m stiffness) may be assessed using stress and strain by STE. We sought to validate e-c stiffness and e-m stiffness by STE against those by catheterization and to evaluate the clinical utility in patients with normal LVEF. Methods: Validation was performed in 126 patients and LV chamber stiffness was obtained as LV pressure change (EDP minus mP) by catheterization divided by LV volume change that equals to stroke volume by echocardiography. STE was performed in 58 controls, 110 hypertension (HTN), 155 HTN with hemodialysis (HD), 48 HTN heart failure with preserved EF (HFpEF) and 34 aortic stenosis (AS). The ePCWP was noninvasively calculated as 10.8 - 12.4 x Log (left atrial active emptying function / minimum volume) (KT index). LVEDP (e-EDP) was estimated as 12.3 - 10.1 x KT index. The eTau is obtained as isovolumic relaxation time / (ln 0.9 x systolic blood pressure - ln ePCWP). The e-c stiffness was noninvasively obtained using e-EDP and 5 mmHg as mP because mP by catheterization was 5.0±2.9mmHg. LVED stress (e-stress) was estimated as e-EDP x LV dimension / thickness. Results: The eTau and e-EDP by STE had a good correlation with Tau and EDP by catheterization (r=0.75 and 0.63, p<0.001). The e-c stiffness and e-stress had a good correlation with stiffness and stress by catheterization (r=0.69 and 0.77, p<0.001). LV stiffness was most increased in HFpEF. Conclusions: LV relaxation and LV stiffness may be noninvasively assessed by STE with reasonable accuracy and may have a utility and value in the routine clinical practice. [ABSTRACT FROM AUTHOR]