Prognostic Impact of the Ratio of Acceleration Time to Ejection Time in Patients With Low Gradient Severe Aortic Stenosis and Preserved Ejection Fraction.

The clinical management of patients with low gradient severe aortic stenosis (LG-SAS) and preserved left ventricular ejection fraction (LVEF) remains challenging owing to their heterogeneity. The aim to this study was to evaluate the relation between an ejection dynamic parameter linked to AS severity and outcome, the ratio of acceleration time (AT) to ejection time (ET), in a cohort of patients with LG-SAS and preserved LVEF. Three hundred and fifty-six patients with LG-AS (defined by AVA ≤1 cm² and/or AVAi ≤0.6 cm²/m² and mean aortic pressure gradient <40 mm Hg) and preserved LVEF ≥50% were studied. The relation between AT/ET and all-cause and cardiac mortality during follow-up was studied. Median follow-up was 41 months (interquartile range, 35 to 47 months). Median AT/ET was 0.32 (interquartile range, 0.29 to 0.36). The 5-year estimates of all-cause and cardiac mortality were respectively 57 ± 7%, 36 ± 7% for patients with AT/ET >0.36 versus 43 ± 4%, 16 ± 3% for patients with AT/ET ≤0.36 (p = 0.024 and p <0.001, respectively). After adjustment on known predictors of outcome including aortic valve replacement used as a time-dependent covariate, there was a significant increase in all-cause mortality risk for patients with AT/ET >0.36 (adjusted hazard ratio 2.04 [95% confidence interval, 1.32 to 3.13]; p = 0.001) and cardiac mortality risk (adjusted hazard ratio 2.89 [95% confidence interval, 1.54 to 5.43]; p<0.001) compared with patients with AT/ET ≤0.36. The association of AT/ET >0.36 and all-cause or cardiac mortality risk was consistent in subgroups of patients with LG-SAS and preserved EF. In conclusion, an AT/ET ratio of more than 0.36 is an independent predictor of mortality in patients with LG-SAS and preserved EF.

Assessment of left ventricular size and function by 3-dimensional transthoracic echocardiography: Impact of the echocardiography platform and analysis software.

BACKGROUND: Whether echocardiography platform and analysis software impact left ventricular (LV) volumes, ejection fraction (EF), and stroke volume (SV) by transthoracic tridimensional echocardiography (3DE) has not yet been assessed. Hence, our aim was to compare 3DE LV end-diastolic and end-systolic volumes (EDV and ESV), LVEF, and SV obtained with echocardiography platform from 2 different manufacturers. METHODS: 3DE was performed in 84 patients (65% of screened consecutive patients), with equipment from 2 different manufacturers, with subsequent off-line postprocessing to obtain parameters of LV function and size (Philips QLAB 3DQ and General Electric EchoPAC 4D autoLVQ). Twenty-five patients with clinical indication for cardiac magnetic resonance imaging served as a validation subgroup. RESULTS: LVEDV and LVESV from 2 vendors were highly correlated (r = 0.93), but compared with 4D autoLVQ, the use of Qlab 3DQ resulted in lower LVEDV and LVESV (bias: 11 mL, limits of agreement: -25 to +47 and bias: 6 mL, limits of agreement: -22 to +34, respectively). The agreement between LVEF values of each software was poor (intraclass correlation coefficient 0.62) despite no or minimal bias. SVs were also lower with Qlab 3DQ advanced compared with 4D autoLVQ, and both were poorly correlated (r = 0.66). Consistently, the underestimation of LVEDV, LVESV, and SV by 3DE compared with cardiac magnetic resonance imaging was more pronounced with Philips QLAB 3DQ advanced than with 4D autoLVQ. CONCLUSIONS: The echocardiography platform and analysis software significantly affect the values of LV parameters obtained by 3DE. Intervendor standardization and improvements in 3DE modalities are needed to broaden the use of LV parameters obtained by 3DE in clinical practice.

Prospective comparison of speckle tracking longitudinal bidimensional strain between two vendors.

BACKGROUND: Speckle tracking is a relatively new, largely angle-independent technique used for the evaluation of myocardial longitudinal strain (LS). However, significant differences have been reported between LS values obtained by speckle tracking with the first generation of software products. AIMS: To compare LS values obtained with the most recently released equipment from two manufacturers. METHODS: Systematic scanning with head-to-head acquisition with no modification of the patient's position was performed in 64 patients with equipment from two different manufacturers, with subsequent off-line post-processing for speckle tracking LS assessment (Philips QLAB 9.0 and General Electric [GE] EchoPAC BT12). The interobserver variability of each software product was tested on a randomly selected set of 20 echocardiograms from the study population. RESULTS: GE and Philips interobserver coefficients of variation (CVs) for global LS (GLS) were 6.63% and 5.87%, respectively, indicating good reproducibility. Reproducibility was very variable for regional and segmental LS values, with CVs ranging from 7.58% to 49.21% with both software products. The concordance correlation coefficient (CCC) between GLS values was high at 0.95, indicating substantial agreement between the two methods. While good agreement was observed between midwall and apical regional strains with the two software products, basal regional strains were poorly correlated. The agreement between the two software products at a segmental level was very variable; the highest correlation was obtained for the apical cap (CCC 0.90) and the poorest for basal segments (CCC range 0.31-0.56). CONCLUSIONS: A high level of agreement and reproducibility for global but not for basal regional or segmental LS was found with two vendor-dependent software products. This finding may help to reinforce clinical acceptance of GLS in everyday clinical practice.