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This article is part of the supplement: Abstracts of the 15th Annual SCMR Scientific Sessions: 2012

Open Access Poster presentation

CMR validation of fractional changes in annulo-apical angles and TAPSE for rapid assessment of right ventricular systolic function

Simon A Zakeri13*, Alexander Borg2 and Matthias Schmitt12

  • * Corresponding author: Simon A Zakeri

Author Affiliations

1 University of Manchester, Manchester, UK

2 Cardiology, Cardiovascular Division, University Hospital of South Manchester, Manchester, UK

3 Manchester Medical School, Manchester, UK

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Journal of Cardiovascular Magnetic Resonance 2012, 14(Suppl 1):P284  doi:10.1186/1532-429X-14-S1-P284

The electronic version of this article is the complete one and can be found online at: http://www.jcmr-online.com/content/14/S1/P284


Published:1 February 2012

© 2012 Zakeri et al; licensee BioMed Central Ltd.

This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Background

Volumetric assessment of the right ventricle (RV) by Cardiac Magnetic Resonance (CMR), albeit time-consuming, provides accurate and reproducible measurement of RV ejection fraction (RVEF). Tricuspid annulus peak systolic excursion (TAPSE) is a predominantly Echo-validated rapidly-derived surrogate of RV function. Correlations between RVEF and systolic changes in annulo-apical angles (AAAs) have not previously been evaluated.

Objective

To assess the use of changes in AAAs and TAPSE as rapidly-derived surrogate markers of RV systolic function using CMR.

Methods

We measured RV volumes from short-axis bSSFP stacks in patients undergoing clinically indicated CMR scans. RVEF was calculated from volumes derived by semi-automated endocardial contouring (QMass®MR 7.2). AAAs (α,β,θ angles -see figure 1), subtended by a triangle connecting the medial and lateral extent of the tricuspid valve annulus and RV apex, and fractional changes in AAAs (ΔAAA/EDAAAx100, whereby ΔAAA=EDAAA-ESAAA) were measured from end-diastolic (ED) and end-systolic (ES) 4chamber SSFP cine still frames. TAPSE was measured as the change in length of a line connecting the lateral tricuspid valve annulus with the RV apex from ED to ES. Parameters were compared with RVEF using Spearman rank correlations; ROC curves constructed to assess accuracy of the parameters in predicting an RVEF<50%.

thumbnailFigure 1. AAAs in ED on a 4chamber view.

thumbnailFigure 2. Scatter graph -fractional θ angle change vs. RVEF, with line of best fit. Patient subgroups are colour coded. The dotted vertical line represents the ROC cut-off of RVEF<50%, and the dashed horizontal line represents the corresponding cut-off value for fractional θ angle change of ≥ -25.5%.

Results

Forty subjects were included: 10 normals, 10 mildly-impaired, 10 moderately-impaired, and 10 with severely-impaired RV systolic function. Median (25th-75th percentile) RVEF for each subgroup was 53.5% (51.4%-55.7%), 41.5% (38.1%-47.2%), 30.0% (21.7%-33.5%), and 15.8% (9.6%-21.2%), respectively. Correlations with RVEF: TAPSE (0.74 p<0.001), fractional changes of α angle (0.64, p<0.001), β angle (-0.39, p<0.05), and θ angle, which had the highest correlation (-0.77, p<0.001). Smaller increases or a decrease in magnitude of the θ angle from ED to ES are associated with lower RVEFs, whereby a fractional θ angle change of ≥ -25.5% predicts RVEF<50% [97% sensitivity, 91% specificity, AUC=0.98]. The cut-off for TAPSE is ≤1.87cm [100% sensitivity, 82% specificity, AUC=0.98]. Intra- and inter-observer reproducibility is excellent as shown by intra-class correlation coefficients for TAPSE (0.98 and 0.92, respectively) and fractional θ angle change (0.96 and 0.80, respectively).

Conclusions

Both fractional θ angle change and TAPSE strongly correlate with RVEF, and are accurate predictors of RVEF<50%. These measurements provide an excellent alternative to the more time-consuming derivation of RVEF obtained volumetrically by endocardial chamber tracing.

Funding

No funding.