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320-Slice Cardiac CT Assessment of LA Volume: Influence of Acquisition Timing and Comparison with Echocardiography
S12
Heart, Lung and Circulation 2009;18S:S1–S286
Abstracts
ABSTRACTS
Cardiac Imaging 21 EVALUATION OF A NOVEL TWO-DIMENSIONAL ECHOCARDIOGRAPHIC METHOD TO MEASURE MITRAL VALVE AREA IN RHEUMATIC MITRAL STENOSIS USING A SIMPLE ELLIPSE CALCULATION D. Schlosshan, G. Aggarwal, G. Mathur, C. Alexopoulos, R. Allan, G. Cranney Prince of Wales Hospital, Sydney, Australia Background: In clinical practice the use of conventional 2D echocardiography to measure mitral valve area (MVA) is associated with inaccuracies. Based on the assumption that the mitral valve orifice geometry is similar to an ellipse we evaluated a novel method of measuring MVA based on a simple ellipse area calculation. Methods: Nineteen consecutive patients with moderate to severe rheumatic mitral stenosis (female 71%, AF 55%) referred for echocardiographic assessment were retrospectively evaluated. All patients underwent standard 2D transthoracic (TTE) and 3D transoesophageal echocardiogram (3D TOE). Diameters required for the ellipse MVA calculation (MVAellipse ) were measured by simultaneously imaging two orthogonal planes showing the greatest separation of scallops in diastole: the bi-commissural view and a view orthogonal to this using a 2D matrix array probe. Comparisons were made with MVA measured by 2D planimetry (MVA2D ), 3D planimetry (MVA3D ) and pressure half time (MVAPHT ). Results: MVA assessed by MVAellipse , MVA3D , MVA2D , MVAPHT (mean ± SD [cm2 ]) was 0.86 ± 0.31, 1.08 ± 0.4, 1.18 ± 0.33 and 1.23 ± 0.32, respectively. Correlation between MVAellipse and MVA3D (r = 0.93; P < 0.0001), MVA2D (r = 0.89, P = 0.002) and MVAPHT (r = 0.80, P < 0.0001) was excellent. MVAellipse was significantly smaller than MVA3D (P < 0.0001), MVAPHT (P < 0.0001) and MVA2D (P < 0.005) but of little clinical significance. Intra- and inter-observer measurement differences were 0.04 ± 0.06 cm2 and 0.01 ± 0.06 cm2 , respectively (P = NS). Conclusion: Ellipse area calculation may complement conventional 2D measurements and offer a simple and reproducible tool in echocardiographic assessment of MVA in patients with mitral stenosis. doi:10.1016/j.hlc.2009.05.023 22 320-SLICE CARDIAC CT ASSESSMENT OF LA VOLUME: INFLUENCE OF ACQUISITION TIMING AND COMPARISON WITH ECHOCARDIOGRAPHY S.M. Lockwood, S. Moir, M. Seneviratne, P.M. Mottram
Crossett, W.
Thai, S.K.
Monash Cardiovascular Research Centre, MonashHEART and Monash University Department of Medicine (MMC), Melbourne, Australia Background: Increased left atrial volume index (LAVI) is independently predictive of adverse cardiovascular
outcomes; accurate measurement is clinically important. Due to asymmetric LA geometry, currently recommended transthoracic echocardiographic (TTE) techniques may underestimate true LAVI; however current clinically applicable cutoffs are based on TTE data. We therefore compared LAVI analysis using a guideline recommended TTE technique against 320 slice cardiac computed tomography (CT) as the gold standard. In addition, the effect of timing within the cardiac cycle on CT-derived volume was examined. Methods: 29 patients (16 male, 62 ± 15 years) presenting with chest pain who underwent both 320 slice cardiac CT and TTE were studied. As per current guidelines, TTE LA volume was measured at end-ventricular systole (EVS) using the biplane area-length method. Cardiac CT was performed with prospective gating and LA contrast opacification; LA volumes were analysed at both EVS and end-ventricular diastole (EVD) using commercial software (Vitrea2, Toshiba). Both volume analysis strategies excluded LA-appendage and pulmonary veins; all volumes were indexed to body surface area. Results: As expected, LAVI by CT was significantly influenced by timing within the cardiac cycle: EVS 53.9 ± 18.2 ml/m2 vs. EVD 46.3 ± 15.2 ml/m2 (p < 0.0001). TTE LAVI at EVS (48.1 ± 16.3 ml/m2 ) was significantly lower than CT LAVI at EVS (p = 0.007), but similar to CT LAVI at EDS (p = 0.41). Time between CT and TTE was 20 ± 22 days. Conclusion: Measurement of LA volume with TTE as per current guidelines significantly underestimates true LA volume. Timing of acquisition significantly influences CT-derived LA volume and should be specified in clinical validation studies. doi:10.1016/j.hlc.2009.05.024 23 3D TOE ASSESSMENT OF PFO ANATOMY: SURPRISING RESULTS WITH IMPLICATIONS FOR PERCUTANEOUS CLOSURE S.M. Lockwood, W. Thai, S. Moir, I.T. Meredith, R.W. Harper, P.M. Mottram Monash Cardiovascular Research Centre, MonashHEART and Monash University Department of Medicine (MMC), Melbourne, Australia Background: Detailed understanding of patent foramen ovale (PFO) anatomy is crucial to the design of percutaneous closure devices. PFO geometry is commonly believed to be characterised by an elliptic cylinder. However, whilst two-dimensional (2D) trans-oesophageal echo (TOE) measurements of PFO length and height have been reported, in vivo assessment of PFO width requires 3D techniques, and has not been fully studied. Methods: 3D TOE imaging (Philips IE33 3D probe) was performed in 17 patients (10 females, age 63 ± 15 years) in whom PFO had previously been identified with 2D TOE imaging. Optimised 3D zoom images were obtained from a single cardiac cycle and analysed offline using commercial
Heart, Lung and Circulation 2009;18S:S1–S286
Abstracts
ABSTRACTS
Cardiac Imaging 21 EVALUATION OF A NOVEL TWO-DIMENSIONAL ECHOCARDIOGRAPHIC METHOD TO MEASURE MITRAL VALVE AREA IN RHEUMATIC MITRAL STENOSIS USING A SIMPLE ELLIPSE CALCULATION D. Schlosshan, G. Aggarwal, G. Mathur, C. Alexopoulos, R. Allan, G. Cranney Prince of Wales Hospital, Sydney, Australia Background: In clinical practice the use of conventional 2D echocardiography to measure mitral valve area (MVA) is associated with inaccuracies. Based on the assumption that the mitral valve orifice geometry is similar to an ellipse we evaluated a novel method of measuring MVA based on a simple ellipse area calculation. Methods: Nineteen consecutive patients with moderate to severe rheumatic mitral stenosis (female 71%, AF 55%) referred for echocardiographic assessment were retrospectively evaluated. All patients underwent standard 2D transthoracic (TTE) and 3D transoesophageal echocardiogram (3D TOE). Diameters required for the ellipse MVA calculation (MVAellipse ) were measured by simultaneously imaging two orthogonal planes showing the greatest separation of scallops in diastole: the bi-commissural view and a view orthogonal to this using a 2D matrix array probe. Comparisons were made with MVA measured by 2D planimetry (MVA2D ), 3D planimetry (MVA3D ) and pressure half time (MVAPHT ). Results: MVA assessed by MVAellipse , MVA3D , MVA2D , MVAPHT (mean ± SD [cm2 ]) was 0.86 ± 0.31, 1.08 ± 0.4, 1.18 ± 0.33 and 1.23 ± 0.32, respectively. Correlation between MVAellipse and MVA3D (r = 0.93; P < 0.0001), MVA2D (r = 0.89, P = 0.002) and MVAPHT (r = 0.80, P < 0.0001) was excellent. MVAellipse was significantly smaller than MVA3D (P < 0.0001), MVAPHT (P < 0.0001) and MVA2D (P < 0.005) but of little clinical significance. Intra- and inter-observer measurement differences were 0.04 ± 0.06 cm2 and 0.01 ± 0.06 cm2 , respectively (P = NS). Conclusion: Ellipse area calculation may complement conventional 2D measurements and offer a simple and reproducible tool in echocardiographic assessment of MVA in patients with mitral stenosis. doi:10.1016/j.hlc.2009.05.023 22 320-SLICE CARDIAC CT ASSESSMENT OF LA VOLUME: INFLUENCE OF ACQUISITION TIMING AND COMPARISON WITH ECHOCARDIOGRAPHY S.M. Lockwood, S. Moir, M. Seneviratne, P.M. Mottram
Crossett, W.
Thai, S.K.
Monash Cardiovascular Research Centre, MonashHEART and Monash University Department of Medicine (MMC), Melbourne, Australia Background: Increased left atrial volume index (LAVI) is independently predictive of adverse cardiovascular
outcomes; accurate measurement is clinically important. Due to asymmetric LA geometry, currently recommended transthoracic echocardiographic (TTE) techniques may underestimate true LAVI; however current clinically applicable cutoffs are based on TTE data. We therefore compared LAVI analysis using a guideline recommended TTE technique against 320 slice cardiac computed tomography (CT) as the gold standard. In addition, the effect of timing within the cardiac cycle on CT-derived volume was examined. Methods: 29 patients (16 male, 62 ± 15 years) presenting with chest pain who underwent both 320 slice cardiac CT and TTE were studied. As per current guidelines, TTE LA volume was measured at end-ventricular systole (EVS) using the biplane area-length method. Cardiac CT was performed with prospective gating and LA contrast opacification; LA volumes were analysed at both EVS and end-ventricular diastole (EVD) using commercial software (Vitrea2, Toshiba). Both volume analysis strategies excluded LA-appendage and pulmonary veins; all volumes were indexed to body surface area. Results: As expected, LAVI by CT was significantly influenced by timing within the cardiac cycle: EVS 53.9 ± 18.2 ml/m2 vs. EVD 46.3 ± 15.2 ml/m2 (p < 0.0001). TTE LAVI at EVS (48.1 ± 16.3 ml/m2 ) was significantly lower than CT LAVI at EVS (p = 0.007), but similar to CT LAVI at EDS (p = 0.41). Time between CT and TTE was 20 ± 22 days. Conclusion: Measurement of LA volume with TTE as per current guidelines significantly underestimates true LA volume. Timing of acquisition significantly influences CT-derived LA volume and should be specified in clinical validation studies. doi:10.1016/j.hlc.2009.05.024 23 3D TOE ASSESSMENT OF PFO ANATOMY: SURPRISING RESULTS WITH IMPLICATIONS FOR PERCUTANEOUS CLOSURE S.M. Lockwood, W. Thai, S. Moir, I.T. Meredith, R.W. Harper, P.M. Mottram Monash Cardiovascular Research Centre, MonashHEART and Monash University Department of Medicine (MMC), Melbourne, Australia Background: Detailed understanding of patent foramen ovale (PFO) anatomy is crucial to the design of percutaneous closure devices. PFO geometry is commonly believed to be characterised by an elliptic cylinder. However, whilst two-dimensional (2D) trans-oesophageal echo (TOE) measurements of PFO length and height have been reported, in vivo assessment of PFO width requires 3D techniques, and has not been fully studied. Methods: 3D TOE imaging (Philips IE33 3D probe) was performed in 17 patients (10 females, age 63 ± 15 years) in whom PFO had previously been identified with 2D TOE imaging. Optimised 3D zoom images were obtained from a single cardiac cycle and analysed offline using commercial