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Can Cardiac CT be Used to Assess LA Size?
S188
Abstracts CSANZ 2012 Abstracts
ABSTRACTS
455 Can Cardiac CT be Used to Assess LA Size? M. Truong 1,2,3 , D. Moses 1 , L. Thomas 1,2,∗ , S. Eshoo 3 1 Liverpool
Hospital, Sydney, NSW, Australia University of New South Wales 3 Campbelltown Hospital and University of Western Sydney, Sydney, NSW, Australia 2 The
Objective: Left atrial (LA) size is a prognostic marker for adverse cardiovascular events. We compared LA volume measured by multi detector computed tomography (MDCT) and transthoracic echocardiography (TTE) in patients undergoing cardiac CT evaluation of coronary artery disease. Methods: Fifty-one patients were examined with a 64 slice MDCT (dual source) and TTE. The following parameters were measured: antero-posterior LA length from the parasternal long axis view (PLAX), maximum length and width and maximum and minimum LA areas from the apical 4-chamber view. LA volume was calculated by the area-length and prolate ellipse methods and indexed to body surface area. MDCT and TTE measurements were compared using Pearson’s correlation. Bland–Altman analysis was used to compare differences between the two modalities. Results: MDCT and TTE measurements correlated well: PLAX (r = 0.56), maximum area (r = 0.54), minimum area (r = 0.53), indexed area-length (r = 0.55) and indexed prolate ellipse (r = 0.53), (all p < 0.001). TTE underestimated indexed LA volume by the area-length method; TTE vs. CT (29 ± 10 mL/m2 vs. 40 ± 14 mL/m2 , p < 0.001) as well as the prolate ellipse method; TTE vs. CT (21 ± 6 mL/m2 vs. 27 ± 9 mL/m2 , p < 0.001). Bland–Altman plots for all parameters except maximum length demonstrated an underestimation on TTE compared with MDCT with less agreement at larger LA sizes. Conclusion: Cardiac MDCT can be used to evaluate LA size but cannot be used interchangeably with TTE measurements. Correlation is lower between the techniques with greater LA enlargement. http://dx.doi.org/10.1016/j.hlc.2012.05.466 456 Cardiac Magnetic Resonance Derived Relative Atrial Index Accurately Identifies Secundum Atrial Septal Defects V. Cox 1,2,∗ , J. Richardson 1,2 , A. Nelson 1,2 , M. Cunnington 1 , D. Wong 1,2 , A. Bertaso 1 , K. Teo 1,2 , M. Worthley 1,2 , S. Worthley 1,2 1 Cardiovascular Research Centre, Royal Adelaide Hospital, Australia 2 Department of Medicine, University of Adelaide, South Australia, Australia
Background: Atrial septal defects (ASDs) can be challenging to diagnose and surrogate markers have been proposed to facilitate this task. The relative atrial index
Heart, Lung and Circulation 2012;21:S143–S316
(RAI), the ratio of right to left atrial area, has been advocated to be sensitive and specific for ASDs when RAI > 1.0 in the absence of other identifiable causes. To date, studies have used transthoracic echocardiography to measure RAI. Cardiac magnetic resonance (CMR) offers greater endocardial definition and precise imaging planes. Therefore, we evaluated this index in an ASD cohort utilising CMR. Methods: Fifty-five patients with isolated secundum ASD underwent CMR (Siemens Avanto 1.5T), inclusive of steady state free precession cine imaging. Contourderived atrial area was calculated from the horizontal long axis (4-chamber) image at end-systole. RAI was defined as right atrial area/left atrial area. In those who subsequently had percutaneous ASD closure, repeat CMR assessment was performed. Data presented as mean ± SEM. Results: In the ASD cohort, right atrial area was 29.6 ± 1.4 cm2 and left atrial area was 24.1 ± 0.8 cm2 . Mean RAI was 1.23 ± 0.04. Fifty patients (91.9%) were noted to have an RAI > 1.0, but five patients (9.1%) with confirmed ASD had an RAI < 1.0. Of these false negatives, a conservative approach was followed in four, with one proceeding to closure. In the sub-group who underwent closure (n = 18), right atrial area reduced by 9.0 ± 4 cm2 (p < 0.05) whereas there was a trend to a small reduction in left atrial area (2.0 ± 2.1 cm2 (p = ns). Accordingly, RAI reduced from 1.44 ± 0.1 to 1.18 ± 0.1 (p < 0.05). Conclusion: CMR-derived RAI has high sensitivity for identifying significant secundum ASDs and may provide a useful measure of atrial remodeling following closure. http://dx.doi.org/10.1016/j.hlc.2012.05.467 457 Cardiac Magnetic Resonance Imaging After Transcatheter Aortic Valve Implantation J. Richardson 1,2,∗ , M. Cunnington 1 , D. Wong 1,2 , A. Bertaso 1 , A. Nelson 1,2 , S. Azarisman 1,2 , H. Chua 1 , K. Williams 1 , B. Koschade 1 , M. Worthely 1,2 , K. Teo 1,2 , S. Worthley 1,2 1 Cardiovascular Research Centre, Royal Adelaide Hospital, Australia 2 University of Adelaide, Adelaide, SA, Australia
Background: Transcatheter aortic valve implantation (TAVI) is increasingly used for the management of severe aortic stenosis. Understanding the impact of TAVI on cardiac volumes, function and mass may improve the mechanistic understanding of its utility. Cardiac magnetic resonance (CMR) provides the gold standard assessment of these parameters, but CMR data post TAVI is lacking. We assessed the impact of TAVI on CMR parameters at a large Australian centre. Methods: Cine structure/function images and velocity encoded flow acquisitions were performed pre and post TAVI using a 1.5T Siemens Avanto MR scanner. End-diastolic volume (EDV), end-systolic volume (ESV),
Abstracts CSANZ 2012 Abstracts
ABSTRACTS
455 Can Cardiac CT be Used to Assess LA Size? M. Truong 1,2,3 , D. Moses 1 , L. Thomas 1,2,∗ , S. Eshoo 3 1 Liverpool
Hospital, Sydney, NSW, Australia University of New South Wales 3 Campbelltown Hospital and University of Western Sydney, Sydney, NSW, Australia 2 The
Objective: Left atrial (LA) size is a prognostic marker for adverse cardiovascular events. We compared LA volume measured by multi detector computed tomography (MDCT) and transthoracic echocardiography (TTE) in patients undergoing cardiac CT evaluation of coronary artery disease. Methods: Fifty-one patients were examined with a 64 slice MDCT (dual source) and TTE. The following parameters were measured: antero-posterior LA length from the parasternal long axis view (PLAX), maximum length and width and maximum and minimum LA areas from the apical 4-chamber view. LA volume was calculated by the area-length and prolate ellipse methods and indexed to body surface area. MDCT and TTE measurements were compared using Pearson’s correlation. Bland–Altman analysis was used to compare differences between the two modalities. Results: MDCT and TTE measurements correlated well: PLAX (r = 0.56), maximum area (r = 0.54), minimum area (r = 0.53), indexed area-length (r = 0.55) and indexed prolate ellipse (r = 0.53), (all p < 0.001). TTE underestimated indexed LA volume by the area-length method; TTE vs. CT (29 ± 10 mL/m2 vs. 40 ± 14 mL/m2 , p < 0.001) as well as the prolate ellipse method; TTE vs. CT (21 ± 6 mL/m2 vs. 27 ± 9 mL/m2 , p < 0.001). Bland–Altman plots for all parameters except maximum length demonstrated an underestimation on TTE compared with MDCT with less agreement at larger LA sizes. Conclusion: Cardiac MDCT can be used to evaluate LA size but cannot be used interchangeably with TTE measurements. Correlation is lower between the techniques with greater LA enlargement. http://dx.doi.org/10.1016/j.hlc.2012.05.466 456 Cardiac Magnetic Resonance Derived Relative Atrial Index Accurately Identifies Secundum Atrial Septal Defects V. Cox 1,2,∗ , J. Richardson 1,2 , A. Nelson 1,2 , M. Cunnington 1 , D. Wong 1,2 , A. Bertaso 1 , K. Teo 1,2 , M. Worthley 1,2 , S. Worthley 1,2 1 Cardiovascular Research Centre, Royal Adelaide Hospital, Australia 2 Department of Medicine, University of Adelaide, South Australia, Australia
Background: Atrial septal defects (ASDs) can be challenging to diagnose and surrogate markers have been proposed to facilitate this task. The relative atrial index
Heart, Lung and Circulation 2012;21:S143–S316
(RAI), the ratio of right to left atrial area, has been advocated to be sensitive and specific for ASDs when RAI > 1.0 in the absence of other identifiable causes. To date, studies have used transthoracic echocardiography to measure RAI. Cardiac magnetic resonance (CMR) offers greater endocardial definition and precise imaging planes. Therefore, we evaluated this index in an ASD cohort utilising CMR. Methods: Fifty-five patients with isolated secundum ASD underwent CMR (Siemens Avanto 1.5T), inclusive of steady state free precession cine imaging. Contourderived atrial area was calculated from the horizontal long axis (4-chamber) image at end-systole. RAI was defined as right atrial area/left atrial area. In those who subsequently had percutaneous ASD closure, repeat CMR assessment was performed. Data presented as mean ± SEM. Results: In the ASD cohort, right atrial area was 29.6 ± 1.4 cm2 and left atrial area was 24.1 ± 0.8 cm2 . Mean RAI was 1.23 ± 0.04. Fifty patients (91.9%) were noted to have an RAI > 1.0, but five patients (9.1%) with confirmed ASD had an RAI < 1.0. Of these false negatives, a conservative approach was followed in four, with one proceeding to closure. In the sub-group who underwent closure (n = 18), right atrial area reduced by 9.0 ± 4 cm2 (p < 0.05) whereas there was a trend to a small reduction in left atrial area (2.0 ± 2.1 cm2 (p = ns). Accordingly, RAI reduced from 1.44 ± 0.1 to 1.18 ± 0.1 (p < 0.05). Conclusion: CMR-derived RAI has high sensitivity for identifying significant secundum ASDs and may provide a useful measure of atrial remodeling following closure. http://dx.doi.org/10.1016/j.hlc.2012.05.467 457 Cardiac Magnetic Resonance Imaging After Transcatheter Aortic Valve Implantation J. Richardson 1,2,∗ , M. Cunnington 1 , D. Wong 1,2 , A. Bertaso 1 , A. Nelson 1,2 , S. Azarisman 1,2 , H. Chua 1 , K. Williams 1 , B. Koschade 1 , M. Worthely 1,2 , K. Teo 1,2 , S. Worthley 1,2 1 Cardiovascular Research Centre, Royal Adelaide Hospital, Australia 2 University of Adelaide, Adelaide, SA, Australia
Background: Transcatheter aortic valve implantation (TAVI) is increasingly used for the management of severe aortic stenosis. Understanding the impact of TAVI on cardiac volumes, function and mass may improve the mechanistic understanding of its utility. Cardiac magnetic resonance (CMR) provides the gold standard assessment of these parameters, but CMR data post TAVI is lacking. We assessed the impact of TAVI on CMR parameters at a large Australian centre. Methods: Cine structure/function images and velocity encoded flow acquisitions were performed pre and post TAVI using a 1.5T Siemens Avanto MR scanner. End-diastolic volume (EDV), end-systolic volume (ESV),