Can Aortic Stenosis Severity Assessment be Improved by Direct Measurement of Left Ventricular Outflow Tract Area by Computed Tomography?

S166

Heart, Lung and Circulation 2013;22:S126–S266

CSANZ 2013 Abstracts

ABSTRACTS

two-, three-, and four-chamber views. TDI (expressed as average of septal and lateral values) and GLS were analysed using EchoPac. Results: Mean BP of the study group was 136 ± 20/78 ± 10 mmHg, 35 (70%) had hypertension, 21 (42%) had diabetes. As mandated, average e velocity was low (4.6 ± 0.9 cm/s) however mean GLS was relatively preserved at −17.8 ± 2.7%. Ten patients (20%) had GLS > −16%, and three patients (6%) had GLS > −14%. There was no significant correlation between GLS and either septal or lateral e . GLS was weakly correlated to both s’ (r = 0.36, p = 0.01) and s’ integral (r = 0.42, p < 0.01). Conclusion: In a population with a high prevalence of cardiovascular risk factors and markedly abnormal e velocities (but preserved LVEF) the majority of patients had normal 2D strain values and the two parameters were unrelated. GLS and e are not equivalent methods for the identification of subclinical myocardial dysfunction. This may have important practical significance. http://dx.doi.org/10.1016/j.hlc.2013.05.395 394 Assessment of Inter-observer Reproducibility of Left Ventricular Global Longitudinal Strain between an Expert and Novice Observer V. Speranza 1,∗ , A. Yamada 2 , J. Cafaro 1 , M. Ischenko 1 , A. Benjamin 1 , M. Harten 1 , B. Anderson 1 , D. Platts 1 , C. Hamilton-Craig 1 , D. Burstow 1 , J. Chan 1,2 1 The Prince Charles Hospital, Department of Cardiology, Heart

Lung Institute, University of Queensland, Brisbane, Australia Foundation Research Centre, Griffith University, Queensland, Australia

2 Heart

Background: Two-dimensional left ventricular strain analysis by automated function imaging (AFI) software measures left ventricular global longitudinal strain (GLS). Reproducibility of strain analysis using this technique between expert and novice observers remains unclear. In this study, LV strain analysis and time required to complete analysis by an expert observer was compared with a novice observer. Methods: Thirty patients (age 42 ± 20 years, EF 62 ± 9%) underwent transthoracic echocardiography imaging. Images were acquired using a GE Vivid E9 system. Focused apical long axis, four-chamber and two-chamber views of three beats at a frame rate of 40–70 frames/s were obtained. Offline analysis was performed using EchoPAC. LV GLS was measured by an independent, blinded expert observer, compared to an independent, blinded novice observer. Observers recorded the time taken to perform analysis. Statistical analysis was performed using Bland Altman analysis (mean differences ±2 SD) and Pearson’s correlation (r). Results: There was excellent reproducibility of LV GLS between the expert and novice observer (r = 0.96, p < 0.0001, mean difference = 0.2 ± 2). There was no significant difference in mean GLS between the two observers (−20 ± 3.9% vs. −21 ± 3.7%, p = 0.2). However, the average time taken

for strain analysis was significantly different (expert 1.6 ± 0.3 min vs. novice 2.3 ± 0.8 min, p < 0.0001). Conclusion: Excellent reproducibility of GLS measurements between expert and novice observer using automated AFI software suggests potential for widespread application. http://dx.doi.org/10.1016/j.hlc.2013.05.396 395 Can Aortic Stenosis Severity Assessment be Improved by Direct Measurement of Left Ventricular Outflow Tract Area by Computed Tomography? S. Lockwood ∗ , P. Mottram, I. Meredith, J. Cameron, S. Moir MonashHeart and Monash Cardiovascular Research Centre, Southern Clinical School, Monash University, Melbourne, Australia Background: Estimation of aortic valve area (AVA) using the continuity equation is vulnerable to measurement error. Left ventricular outflow tract dimension (LVOTd) is often underestimated by echocardiography (TTE) and when squared in the continuity equation, may lead to an underestimation of AVA. Computed tomography (CT) is often used for the delineation of aortic anatomy prior to therapeutic intervention and thus offers the opportunity for direct measurement of LVOT area (LVOTa), potentially providing a more accurate assessment of AVA. Method: We assessed patients with symptomatic aortic stenosis referred for therapeutic intervention. All patients underwent resting TTE and CT. Echocardiography studies were performed according to established guidelines. CT LVOT area (CTLVOTa) was determined by direct short axis planimetry (using a double-oblique method). AVA was calculated using the continuity equation using either TTELVOTd or CTLVOTa in addition to TTE Doppler data. Results: Sixty-four patients (mean age 83 ± 5 years, 41% female) were analysed. The majority of patients had preserved LV ejection fraction (77%, LVEF >50%) and the mean aortic valve gradient (MAVG) was 46 ± 17 mmHg. CTLVOTa AVA was larger than the TTELVOTd AVA (0.85 ± 0.26 cm2 vs. 0.65 ± 0.23 cm2 , p < 0.005). CTLVOTa AVA demonstrated a stronger correlation with MAVG (r = −0.44, p < 0.05) than TTELVOTd AVA (r = −0.39, p < 0.05). Conclusion: Aortic valve area is larger when calculated using CT derived LVOT area and correlates better with mean AV gradient than TTE derived AVA. A combined multi-modality approach using CT and TTE may provide a more accurate assessment of AS severity. Further studies with comparison to invasive data are required. http://dx.doi.org/10.1016/j.hlc.2013.05.397