Assessing ASDs prior to device closure using 3D echocardiography. Just pretty pictures or a useful clinical tool?

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1 European Journal of Echocardiography (2008) 9, doi: /j.euje Assessing ASDs prior to device closure using 3D echocardiography. Just pretty pictures or a useful clinical tool? G.J. Morgan*, F. Casey, B. Craig, and A. Sands Department of Paediatric Cardiology, Clark Clinic, Royal Belfast Hospital for Sick Children, Falls Road, Belfast, BT2 6BE, Northern Ireland, UK Received 28 March 2007; accepted after revision 22 July 2007; online publish-ahead-of-print 24 September 2007 KEYWORDS Interventional cardiology; Atrial septal defect; Catheterisation; Congenital heart disease; Atrial septum morphology; Three-dimensional echocardiography Introduction Transcatheter device closure is an alternative to surgical management for haemodynamically significant ASDs in adults and paediatric patients over 10 kg in weight. 5,7 Accurate assessment of an ASD in terms of its morphology, defect size relative to the atrial septal length, position in the atrial septum and adequacy of margins is paramount in determining the suitability for device closure and hence maximising the procedural success rate. 8,14,15 Imaging modalities currently employed include transoesophageal echocardiography (TOE), transthoracic echocardiography (TTE), intracardiac echocardiography (ICE) and fluoroscopy; but they all have their limitations. 6 Three-dimensional echocardiography may prove a useful additional tool. 1 It is noninvasive and radiation free. It uses the same basic principles of image * Corresponding author. Department of Paediatric Cardiology, Ward 32 Paul O Gorman building, Bristol Royal Hospital for Children, Upper Maudlin Street, Bristol, BS2 8BJ, UK. Tel: þ ; fax: þ address: gareth.morgan@ubht.nhs.uk (G.J. Morgan). Aims To determine the usefulness of three-dimensional transthoracic echocardiography (3D echo) in assessment of secundum atrial septal defects (ASDs) considered for device closure. To compare the findings from 3D echo with those from two-dimensional transoesophageal echocardiography (TOE) regarding dimensions, morphology and suitability for device closure. Methods and results Twenty-four patients were enrolled in this prospective, crossover study. Threedimensional echo and TOE data were collected, analysed and compared, assessing quantitative data including maximum defect diameter, area and circumference. Qualitative morphology such as the presence of fenestrations and the defect margins were noted, and an assessment of the suitability for device closure was made using each modality. Eighteen (75%) of the 3D data sets produced usable data for analysis. In each case the maximum diameter of the defect was larger on 3D echo than on TOE (mean difference ¼ 0.34 cm, P, 0.001). On three occasions suitability for device closure could not be determined using 3D echo. On the other 15 occasions there was agreement between the TOE and 3D echo data. Conclusions Three-dimensional echo provides comparable data with TOE when attempting to predict suitability for device closure without the need for general anaesthetic or sedation. It also provides useful additional dynamic and morphological information. acquisition and interpretation as 2D transthoracic imaging. It is a rapidly developing imaging modality in congenital cardiology where it has been shown to provide useful morphological information and aid surgical planning. 9,10,11,12 Technological advances have allowed a decrease in transducer footprint size and improved live and off-line processing capabilities making 3D echo a practical everyday diagnostic tool. 13 Methods This was a prospective crossover study based at the Royal Belfast Hospital for Sick Children, Department of Paediatric Cardiology. This unit provides all congenital cardiac services to the 1.7 million population of Northern Ireland. At the time of the study the unit policy was to perform TOE on each patient in order to establish suitability for device closure and define anatomical characteristics. TOEs were not carried out during the same session as the proposed transcatheter closure, but were instead carried out in advance to allow discussion about the suitability of each case. The need to proceed with closure of the defect either by surgical or Published on behalf of the European Society of Cardiology. All rights reserved. & The Author For permissions please journals.permissions@oxfordjournals.org.

2 Assessing ASDs using 3D Echo 479 transcatheter technique had already been determined in terms of symptomatology and the presence of right heart volume loading on transthoracic 2D echocardiography. TOEs were performed with the ATL (Pennsylvania, USA) Ultrasound Phased Array MPT7-4 and BPT9-5 probes. Ethical approval was granted from the local ethics committee at the Royal Victoria Hospital, Belfast. Written consent was obtained from 24 successive patients or parents attending for day case TOE assessment of secundum ASDs. All of the patients had had recent 2D echo assessments confirming the presence of a significant ASD. Three-dimensional volumes were obtained while the patient was waiting for their TOE or immediately following the procedure. Three-dimensional data were obtained as full-volume data sets using the 3D probe of the Philips Sonos No attempt was made to check the quality or adequacy of the 3D data sets during or immediately after acquisition. The data were anonymised and shuffled before detailed offline analysis using TomTec 4D Cardio-view TM RT Software. The TOE and 3D scans were carried out by different physicians and neither the operators nor the patients were aware of the result of the other investigation at the time. The anonymised 3D data sets were shuffled with data from 12 normal patients prior to analysis. The analysis would otherwise have been prejudiced by the operator s prior knowledge that each patient had a significant ASD. The reconstructed anonymised septal images and movies were then presented to one consultant paediatric cardiologist who made a decision as to whether the defect was suitable for catheter closure. The same consultant had also performed the TOEs and made a separate decision on the basis of that data. Data collection and end points On TOE the maximum diameter of the defect was recorded as was the septal length and the adequacy of the mitral, aortic, SVC (superior vena cava) and IVC (inferior vena cava) rims. The presence of a fenestrated defect or other anatomical variants was also recorded. Based on this information a decision was taken as to whether a defect was suitable for transcatheter closure. Three-dimensional analysis involved isolating the atrial septum including all the relevant margins to produce an en-face moving image of the whole atrial septum from left and right atrial aspects, throughout the cardiac cycle. This allowed the area, maximum diameters, margins, shape and anatomical details including fenestrations to be assessed (Figure 1). Analysis of the various margins was performed by measuring the shortest distance connecting the edge of the septal defect to the structure defining the rim, from both right and left atrial en-face views of the septum. The major end point was to determine if suitability for attempted device closure could be assessed using 3D compared to the gold standard of TOE. The identification of anatomical variations pertinent to the closure (namely the presence of fenestrations) was also assessed in both modalities. The device used most commonly in the unit was the Amplatzer Atrial Septal Occluder (AGA Medical) and decisions regarding transcatheter closure were based on that device s characteristics. Statistical significance was calculated using Student s t-test. Suitability for device closure was based on the following points: (1) Adequacy of all four margins. (2) Adequate septal length compared to the maximum diameter of the defect. Figure 1 aspect. (3) Maximum diameter compared to the weight of the patient. Presence of significant fenestrations or multiple defects likely to lead to unsuitability. Results Twenty-four consecutive patients were enrolled in the study. The age range was 3 26 years (median ¼ 7 years). Fifteen of the patients were female (62.5%). Of the 24 patients enrolled, 6 studies (25%) had to be discarded due to poor quality 3D data, mostly due to stitching (movement artefact) in the 3D volume. No ASDs were falsely diagnosed in the 12 normal patients. The maximum diameter of the defect was consistently larger in the 3D in comparison to the TOE study (mean difference ¼ 0.34 cm, P, 0.001; Table 1). On three occasions the margins of the defect were not seen sufficiently clearly on the 3D study to comment on suitability for percutaneous closure. There was complete agreement between the 3D and TOE regarding suitability in the other 15 patients (83%). Two defects were noted to be fenestrated on 3D whereas only one of these was noted on TOE. The fenestration not identified on TOE was confirmed at the time of surgical correction. The irregular shape of the defects was very obvious on 3D echo with over half of the ASDs being irregular. Also notable was the change in area and shape of the defects between systole and diastole (Figure 2) with a 62.3% change in mean area during the cardiac cycle (P, 0.001). 2 Discussion 3D en-face measurement of an ASD from right atrial Three-dimensional echocardiography (3D echo) has moved from the research lab to become a daily clinical tool. It is an economical, non-invasive method of demonstrating dynamic morphology. There is currently considerable debate regarding the most appropriate imaging technique to guide device closure of atrial septal defects (ASD), both in terms of pre-procedure selection and guidance of device placement in the catheter lab.

3 480 Table 1 ASD dimensions and decisions regarding suitability for device closure based on 3D and TOE data Patient 3D assessment TOE Atrial systole Atrial diastole Device closable? Maximum diameter Device closable? Maximum diameter Area Circumference Maximum Diameter Area Circumference Reasons Reasons A Y 1.1 Y B N Large defect in small septum 2.3 N Large defect in small septum D ? IVC margin unclear 1.7 Y F N Fenestrated 1.6 N Fenestrated G Y 1.4 Y H Y 0.7 Y I N Deficient mitral þ aortic margins 1.8 N Deficient aortic margin J ? IVC margin unclear 2.4 Y K Y 1.6 Y N Y 1.2 Y O N Deficient mitral margin 0.9 N Deficientmitral margin P Y 1.4 Y R Y 1 Y S Y 1 Y T N Fenestrated þ deficient aortic 0.8 N Deficient aortic margin margin U Y 0.7 Y W ? IVC margin unclear 0.5 N Deficient inferior margin X Y 0.8 Y All measurements are in cm or cm 2.Y¼ Yes; N ¼ No. Patients C, E, L, M, Q and V were not included as their data sets were inadequate. G.J. Morgan et al. Downloaded from at Pennsylvania State University on March 5, 2014

4 Assessing ASDs using 3D Echo 481 Figure 2 Overlays from a 3D reconstruction of an en face right atrial view of an ASD in atrial diastole (top) and systole (bottom), demonstrating the significant change in area, circumference and morphology of an ASD during the cardiac cycle. Using a very conservative protocol, there was very good agreement between TOE and 3D echo imaging. Even in units where pre-procedural TOE is not routinely employed, 3D would add significant data to that of standard 2D imaging and may improve efficiency by accurately predicting patients who may not be suitable for device closure without the need for costly and comparatively high risk TOE. The size difference between TOE and 3D assessment is striking, but is in keeping with undersizing on TOE reported by several authors. 6,8 It is our assertion that these size differences are due to a limitation of 2D imaging, where a degree of uncertainty must exist when asserting that the plane of imaging at any particular point in the cardiac cycle will represent the maximum defect diameter. The likelihood of including and measuring the true maximum diameter with 2D imaging is impossible to predict. Imaging the entire depth, width and height of the septum throughout the cardiac cycle with 3D may eliminate or at least reduce this inaccuracy. Stitching, which caused exclusion of six of the patient data sets, occurs when respiratory movement or excessive movement of the probe on the praecordium causes a loss of continuity in the data being acquired by the probe, leading to a visible stitch line in the 3D volume. Despite decreased size and footprint of the imaging probes and rapidly developing software protocols, it remains an unwanted effect particularly in small children and babies. Our study protocol did not include a rapid quality check of the 3D volumes obtained at the patients bedside. Had we undertaken such checks we would doubtless have improved our data quality and the proportion of acceptable 3D studies. During post-processing manipulation of the data set it is possible to create ASDs which do not exist. This remains a weakness of this application of 3D echo. We added several normal scans to our population to ensure that ASDs were not created by manipulation of the image in the false belief that a defect must be present. Another way to overcome this would have been to use 3D colour flow mapping to define flow across the defect; however, this software was incorporated into the system midway through the trial, therefore was not used in the analysis. There is currently a debate regarding the best imaging methods during ASD device closure. It is possible that transthoracic 3D echo may provide a less invasive alternative to ICE and TOE imaging prior to and during the procedure. 4 Balloon sizing aims to convert the irregular elliptic ASD into a circle. One could therefore postulate that the maximum diameter recorded on the 3D data would equate with that at balloon sizing in the cath lab. 16 This could potentially obviate the need for balloon sizing, which is still practised by the majority of operators and is not completely without risk. 17 The emergence of 3D TOE may provide the most useful data. 3 Three-dimensional echocardiography is a useful tool in the assessment of ASDs particularly with regards to suitability for device closure. Further work needs to be done to assess the place of on table 3D echo during device closure. References 1. Van den Bosch AE, Ten Harkel DJ, McGhie JS, Roos-Hesselink JW, Simeons ML, Bogers AJ et al. Characterisation of atrial septal defect assessed by real time 3-dimensional echocardiography. J Am Soc Echocardiogr 2006;19: Xie MX, Fang LY, Wang XF, Lu Q, Lu XF, Yang YL et al. Assessment of atrial septal defect area changes during cardiac cycle by live three-dimensional echocardiography. J Cardiol 2006;47: Abdel-Massih T, Dulac Y, Taktak A, Aggoun Y, Massabuan P, Elbaz M et al. Assessment of atrial defect size with 3D transoesophageal echocardiography: comparison with balloon method. Echocardiography 2005;22: Chen FL, Hsiung MC, Hsieh KS, Li YC, Chou MC. Realtime threedimensional transthoracic echocardiography for guiding amplatzer septal occluder device deployment in patients with atrial septal defect. Echocardiography 2006;23: Bove T, Francois K, DeGroote K, Suys B, DeWolf D, Van Nooten G. Closure of atrial septal defects: is there still a place for surgery? Acta Chir Belg 2005;105: Helgason H, Johansson M, Soderberg B, Eriksson P. Sizing of atrial defects in adults. Cardiology 2005;104: Masura J, Gavora P, Podnar T. Long-term outcome of transcatheter secundum-type atrial septal defect closure using amplatzer septal occluders. J Am Coll Cardiol 2005;45: Durongpisitkul K, Tang NL, Soongswang J, Laohaprasitiporn D, Nanal A. Predictors of successful transcatheter closure of atrial septal defect by cardiacmagnetic resonance imaging. Pediatr Cardiol 2004;25: Lang RM, Mor-Avi V, Sugeng L, Nieman PS, Sahn DJ. Three-dimensional echocardiography: the benefits of the additional dimension. J Am Coll Cardiol 2006;54: Chen FL, Hsiung MC, Nanda N, Hsieh KS, Chou MC. Real-time threedimensional echocardiography in assessing vantricular septal defects: an echocardiographic-surgical correlative study. Echocardiography 2006;23: Khalid O, Koenig P. The use of echocardiography in congenital heart surgery and intervention. Expert Rev Cardiovasc Ther 2006;4:

5 482 G.J. Morgan et al. 12. Fabricius AM, Walther T, Falk V, Mohr FW. Three-dimensional echocardiography for planning of mitral valve surgery: current applicability? Ann Thorac Surg 2004;78: Panza JA. Real-time three-dimensional echocardiography: an overview. Int J Cardiovasc Imaging 2001;17: Reddy SC, Rao PS, Ewenko J, Koscik R, Wilson AD. Echocardiographic predictors of success of catheter closure of atrial septal defect with the buttoned device. Am Heart J 1995;129: Rigatelli G, Cardaioloi P, Braggion G, Aggio S, Giordan M, Magro B et al. Transesophageal echocardiography and intracardiac echocardiography differently predict potential technical challenges or failures of interatrial shunts catheters based closure. J Interv Cardiol 2007;20: Zhu W, Cao QL, Rhodes J, Hijazi ZM. Measurement of atrial septal defect size: a comparative study between three-dimensional transoesophageal echocardiography and the standard balloon sizing methods. Pediatr Cardiol 2000;21: Sivasankaran S, Harikrishnan S, Narayanan N, Jaganmohan T. Laceration of atrial septum during balloon sizing of atrial septal defect. Eur J Echocardiogr 2007;8:89 90.