P4334Characterization of relative pressure profiles in the inflow tract of the normal and ischemic left ventricle. a study by new ultrasonic relative pressure imaging

Abstract

speckle tracking echocardiography (STE) in various cardiac diseases including reduced LV ejection fraction (EF) and validate eTau by invasive Tau measured by catheterization. Methods: Isovolumic relaxation time (IVRT) was reported to be measured by Doppler echo. Pulmonary capillary wedge pressure (PCWP) was reported to be accurately estimated by STE as 10.8 -12.4 x Log (left atrial active emptying function / minimum left atrial volume index). Tau was reported to be calculated as IVRT / (ln LV end-systolic pressure -ln LA pressure or PCWP). Thus, eTau by echo is noninvasively obtained using the formula: eTau = IVRT / (ln 0.9 x systolic blood pressure -ln ePCWP). Echo parameters including eTau, e', E/e' and LV strain were measured just before catheterization in 115 patients (age 72±8) with various cardiac diseases including coronary artery disease, hypertensive heart disease, congestive heart disease, valvular heart disease and atrial fibrillation. Moreover, the accuracy of this eTau was examined in patients with reduced EF <50% versus those with preserved EF. Results: The ePCWP had a good correlation with LV end diastolic pressure (r=0.66, p<0.001). There was a good correlation between eTau estimated by STE and Tau obtained by cardiac catheterization (r=0.75, n=115, p<0.001) and good correlations were noted in both subgroups (reduced EF, n=15, r=0.77 and preserved EF, n=100, r=0.75, both P<0.001), whereas IVRT, e', E/e' and LV peak longitudinal strain had a poor correlation with Tau (r=0.44, 0.37 and 0.47, respectively, all p<0.01). Using eTau cutoff of 45ms, the sensitivity and specificity to predict prolonged Tau (>47ms) was 76 and 83%, respectively and positive and negative predictive value was 71 and 87% with AUC of 0.86. Multiple regression analysis revealed that eTau was the best independent predictor of Tau measured by catheterization among echo parameters. Bland-Altman analysis revealed a good agreement between eTau and Tau without fixed and proportional bias. Conclusions: This study demonstrated that eTau estimated by our noninvasive method using STE has a good correlation with Tau obtained by cardiac catheterization in various cardiac diseases in both patients with preserved and reduced EF. The eTau as an index of LV relaxation can be noninvasively assessed by echocardiography and may have utility and value in routine clinical practice for diagnosis and treatment in diastolic dysfunction. Background: The existence of diastolic intraventricular pressure gradients was first described by high fidelity catheters. Later, also systolic gradients have been shown invasively. We have developed a new method, Ultrasonic Relative Pressure Imaging (RPI), based on the Navier-Stokes equation applied to velocity fields. RPI visualizes and calculates pressure difference (PD) noninvasively. Purpose: Our purpose was to noninvasively characterize normal and ischemic PD waveforms in the left ventricular (LV) inflow tract by RPI. P4334 | BENCH Methods:In an open-chest dog model (n=7), a Millar catheter was introduced into t...