Accuracy and reproducibility of aortic annular measurements obtained from echocardiographic 3D manual and semi-automated software analyses in patients referred for transcatheter aortic valve implantation: implication for prosthesis size selection

Accuracy and reproducibility of aortic annular measurements obtained from echocardiographic 3D... Abstract Aims A 3D transoesophageal echocardiography (3D-TOE) reconstruction tool has recently been introduced. The system automatically configures a geometric model of the aortic root and performs quantitative analysis of these structures. We compared the measurements of the aortic annulus (AA) obtained by semi-automated 3D-TOE quantitative software and manual analysis vs. multislice computed tomography (MSCT) ones. Methods and results One hundred and seventy-five patients (mean age 81.3 ± 6.3 years, 77 men) who underwent both MSCT and 3D-TOE for annulus assessment before transcatheter aortic valve implantation were analysed. Hypothetical prosthetic valve sizing was evaluated using the 3D manual, semi-automated measurements using manufacturer-recommended CT-based sizing algorithm as gold standard. Good correlation between 3D-TOE methods vs. MSCT measurements was found, but the semi-automated analysis demonstrated slightly better correlations for AA major diameter (r = 0.89), perimeter (r = 0.89), and area (r = 0.85) (all P < 0.0001) than manual one. Both 3D methods underestimated the MSCT measurements, but semi-automated measurements showed narrower limits of agreement and lesser bias than manual measurements for most of AA parameters. On average, 3D-TOE semi-automated major diameter, area, and perimeter underestimated the respective MSCT measurements by 7.4%, 3.5%, and 4.4%, respectively, whereas minor diameter was overestimated by 0.3%. Moderate agreement for valve sizing for both 3D-TOE techniques was found: Kappa agreement 0.5 for both semi-automated and manual analysis. Interobserver and intraobserver agreements for the AA measurements were excellent for both techniques (intraclass correlation coefficients for all parameters >0.80). Conclusion The 3D-TOE semi-automated analysis of AA is feasible and reliable and can be used in clinical practice as an alternative to MSCT for AA assessment. transcatheter aortic valve replacement, 3D transoesophageal echocardiography, 3D echocardiographic semi-automated software, aortic annular sizing Introduction Transcatheter aortic valve implantation (TAVI) is nowadays an alternative therapeutic option in patients with severe symptomatic aortic stenosis (AS) at high or intermediate surgical risk or with contraindication to surgery.1,2 Accurate imaging assessment of the aortic valve annulus (AA) is critical for prosthesis sizing. Several imaging techniques have been used for this purpose.3–5 2D echocardiographic images allow the analysis of the annulus diameter in just one view (sagittal plane) and may underestimate the maximal valve annulus diameter.6 Multislice computed tomography (MSCT) achieved a central role in the pre-procedural planning providing also information about the degree of valve calcification and the morphology of the access routes.7 3D transoesophageal echocardiography (3D-TOE) is a safe procedure that does not require iodinated contrast and may constitute a valuable imaging tool during TAVI, providing accurate measurements of the aortic root and geometry. Recent studies suggest that the annulus measurements using 3D-TOE images closely approximate those of MSCT.8,9 3D-TOE reconstruction tools have recently been introduced, which automatically configures a geometric model of the aortic root from the images obtained by 3D-TOE and perform quantitative analyses of the AA.10 However, the accuracy of these methods compared with the standard imaging techniques has not been completely evaluated yet. The aims of this study were: (i) to compare the measurements of the AA obtained by semi-automated quantitative modelling of the root from 3D-TOE data to those obtained by 3D-TOE manual analysis and by MSCT as the ‘gold standard’; (ii) to determine agreements between 3D-TOE manual, semi-automated, and MSCT-derived AA measurements; and (iii) to assess the reproducibility of the methods. Methods Study population From October 2014 to August 2016, 175 consecutive patients with severe symptomatic AS eligible for TAVI in our institution were enrolled in the study and underwent both 3D-TOE and MSCT as part of our TAVI screening protocol. This protocol includes a comprehensive transthoracic and TOE echocardiographic assessment, including 3D-TOE, and MSCT. Three patients did not undergo MSCT due to renal failure. All patients signed informed consent for the diagnostic and therapeutic procedures. Echocardiographic examinations All patients underwent both transthoracic and TOE examination using GE Vivid E9 (GE Healthcare, Milwaukee, WI, USA) ultrasound system equipped with MS5 and 6VT-D probes respectively. A complete 2D, colour, pulsed, and continuous-wave Doppler echocardiogram was performed according to EACVI recommendations.11 Mean transaortic pressure gradient was measured by continuous-wave Doppler, and aortic valve area was calculated by the continuity equation. Furthermore, the distribution of calcifications was determined using a qualitative evaluation by assessing the presence of calcifications from the leaflet tips to the left ventricular outflow tract (LVOT) and focusing on the calcification protruding into LVOT from the annular level. 3D semi-automated aortic annulus measurements Images were taken from a mid-oesophageal position. The 2D image was centred on the aortic valve including 2–4 cm of the LVOT and aortic root in the sector. A zoomed image acquisition modality (electrocardiographically triggered multiple-beat 3D imaging was preferred) was used avoiding stitching artefacts, at a minimum frame rate of 12 fps (minimum frame rate required for semi-automated software analysis). The 3D data sets were digitally stored and transferred on external workstation for offline analysis (EchoPAC version 201). The system automatically aligns the images, but manual correction might be necessary. A mid-systolic frame with the aortic valve fully opened is automatically selected. The image is aligned properly around the centre lines as follows (Figure 1A): Figure 1 View largeDownload slide Measurements of the aortic root obtained by different methods. (A) 4D auto-aortic valve quantification. 1: automatic assessment of the three orthogonal plane, 2: automatic tracking of LVOT, aortic annulus, and aortic root; 3: automatic trace of the LVOT, aortic annulus, and aortic root borders; 4: tracking’s manual modification; 5: optimized tracking. (B) 3D-TOE manual multiplanar reformations of the aortic root. Aortic annular diameters are measured in the sagittal and coronal planes. Aortic annulus area and perimeter are obtained by direct planimetry in the short-axis view at level of the aortic annulus. (C) MSCT multiplanar reformations of the aortic root. Figure 1 View largeDownload slide Measurements of the aortic root obtained by different methods. (A) 4D auto-aortic valve quantification. 1: automatic assessment of the three orthogonal plane, 2: automatic tracking of LVOT, aortic annulus, and aortic root; 3: automatic trace of the LVOT, aortic annulus, and aortic root borders; 4: tracking’s manual modification; 5: optimized tracking. (B) 3D-TOE manual multiplanar reformations of the aortic root. Aortic annular diameters are measured in the sagittal and coronal planes. Aortic annulus area and perimeter are obtained by direct planimetry in the short-axis view at level of the aortic annulus. (C) MSCT multiplanar reformations of the aortic root. lines (yellow/white) are centred in the middle of the cross section view; lines (yellow/white) are centred and oriented in parallel to the walls of the aorta, in the long-axis views; the green line is grabbed and adjusted to the position where final measurements should be performed on. Then the LVOT segmentation process is started: the system automatically tracks the contours of the LVOT, AA, and part of the aorta. The tracking of the edges is checked and manually adjusted if necessary. After the check of the tracking is done, the software is ready to elaborate the results. The available parameters are: AA diameter, diameter derived from circumference; AA maximum Diameter, longest axis of ellipse fitted to the AV annulus; AA minimum Diameter, shortest axis of ellipse fitted to AV annulus; AA circumference; AA area. 3D manual aortic annulus measurements and calculations Offline cropping of the 3D aortic root data sets was performed using three multiplanar reformations planes using flexi-slices reconstruction tool in mid-systole (Figure 1B). Transverse, sagittal, and coronal planes are oriented. All planes intersect at the centre of the opened valve. Sagittal and coronal planes are aligned in parallel to the long axis of the ascending aorta. The orthogonal planes are rotated to identify the hinge points of the aortic valve leaflets, then the transverse plane is repositioned to the level of the hinge points. The orthogonal planes are repeatedly rotated (‘turn around’ rule) to ensure that the hinge points of the aortic valve leaflets are transected by the transverse plane to obtain the annulus short-axis view. Once the plane is defined, the following annular measurements are obtained: area, perimeter, orthogonal maximum/coronal, and minimum/sagittal diameter. MSCT examination All MSCT examinations were performed using a 64-slice CT system (LightSpeed VCT XTE scanner, GE Healthcare). Retrospectively gated scanning of the thorax and the abdomen were performed; electrocardiogram (ECG) dose modulation was used. A non-ionic, iso-osmolar contrast agent with an iodine concentration of 320 mg/mL (Iodixanol, Visipaque 320, GE Healthcare) was used. All enhanced MSCT acquisitions were performed using our dedicated multiphasic injection protocol12: the total amount of contrast medium was tailored to the patient’s body mass index (from 40 mL to 100 mL at an average infusion rate from 3.2 mL/s to 4.5 mL/s); bolus tracking was performed and image acquisition was started when a pre-defined threshold of 350 HU was achieved in the right ventricle. The data set of the contrast-enhanced scan of the heart was reconstructed at 0.6 mm slices with iterative reconstruction for evaluation at 5% intervals within the 0–95% RR range. All images were transferred to an external workstation (AW 4.5, GE Healthcare) for post-processing analysis. For the evaluation of the aortic root, a dedicated post-processing software (CardIQ X-Press, GE Healthcare) was used. Minimum and maximum diameters, perimeter, and area of the annulus were taken in an orthogonal plane at the level of the basal attachments of all three aortic valve cusps using the reconstructed double oblique transverse view (Figure 1C). Hypothetical prosthesis sizing with MSCT as the gold standard We submitted 3D manual and semi-automated AA measurements (diameters, perimeter, and area) to a single TAVI operator for blinded definition of prosthesis sizing according to echocardiographic measurements to test the agreement between the methods. The final valve sizing was based on MSCT measurement: the oversizing was defined according to manufacturers’ recommendations of each one of the prosthesis used in our cath lab. Statistics The data are presented as mean ± standard deviation (SD) or percentage when appropriate. Comparison between both techniques was performed using a paired Student’s t-test. Pearson’s correlation analysis was used to test correlation between variables. Concordance between the techniques was evaluated using Bland–Altman analysis. To determine the intraobserver and interobserver variability, all measurements were repeated by the same observer in two sessions and by a second blinded independent observer in all 175 patients. The repeatability and reproducibility were assessed using the same data sets, by intraclass correlation coefficient (ICCs) and concordance using the Bland–Altman analysis. An excellent agreement was defined as ICC 0.80. Statistical significance was considered for a two-tailed P-value ≤0.05. The analyses were performed using SPSS version 20.0 (SPSS, Inc., Chicago, IL, USA) and GraphPad Prism version 6.00 (GraphPad Software, La Jolla, CA, USA, www.graphpad.com). Results Study population and TAVI procedure The clinical and procedural characteristics of the study population are summarized in Table 1. Table 1 Baseline clinical and echocardiographic characteristics (n = 175) Age (years) 81.3 ± 6.3 Male (%) 77 (44%) Body mass index (kg/m2) 25.2 ± 4.8 STS score 5.5 ± 4.3 STS MM 25 ± 11.4 Euroscore II 9.3 ± 2.9 Logistic euroscore 16.7 ± 11.3 Atrial fibrillation (%) 30.9% Aortic maximal velocity (m/s) 4.31 ± 0.67 Transaortic mean gradient (mmHg) 48.4 ± 13.9 AVA (cm2) 0.77 ± 0.3 AVAi (cm2/m2) 0.44 ± 0.2 EDVi (mL/m2) 64 ± 23.2 ESVi (mL/m2) 29.2 ± 17.6 Ejection fraction (%) 56.4 ± 11.3 Aortic regurgitation (%) 82.4% Mitral regurgitation (%) 95.9% Age (years) 81.3 ± 6.3 Male (%) 77 (44%) Body mass index (kg/m2) 25.2 ± 4.8 STS score 5.5 ± 4.3 STS MM 25 ± 11.4 Euroscore II 9.3 ± 2.9 Logistic euroscore 16.7 ± 11.3 Atrial fibrillation (%) 30.9% Aortic maximal velocity (m/s) 4.31 ± 0.67 Transaortic mean gradient (mmHg) 48.4 ± 13.9 AVA (cm2) 0.77 ± 0.3 AVAi (cm2/m2) 0.44 ± 0.2 EDVi (mL/m2) 64 ± 23.2 ESVi (mL/m2) 29.2 ± 17.6 Ejection fraction (%) 56.4 ± 11.3 Aortic regurgitation (%) 82.4% Mitral regurgitation (%) 95.9% STS, Society of Thoracic Surgeons; MM, morbidity&mortality; AVA, aortic valve area; EDV, end-diastolic volume; ESV, end-systolic volume. Table 1 Baseline clinical and echocardiographic characteristics (n = 175) Age (years) 81.3 ± 6.3 Male (%) 77 (44%) Body mass index (kg/m2) 25.2 ± 4.8 STS score 5.5 ± 4.3 STS MM 25 ± 11.4 Euroscore II 9.3 ± 2.9 Logistic euroscore 16.7 ± 11.3 Atrial fibrillation (%) 30.9% Aortic maximal velocity (m/s) 4.31 ± 0.67 Transaortic mean gradient (mmHg) 48.4 ± 13.9 AVA (cm2) 0.77 ± 0.3 AVAi (cm2/m2) 0.44 ± 0.2 EDVi (mL/m2) 64 ± 23.2 ESVi (mL/m2) 29.2 ± 17.6 Ejection fraction (%) 56.4 ± 11.3 Aortic regurgitation (%) 82.4% Mitral regurgitation (%) 95.9% Age (years) 81.3 ± 6.3 Male (%) 77 (44%) Body mass index (kg/m2) 25.2 ± 4.8 STS score 5.5 ± 4.3 STS MM 25 ± 11.4 Euroscore II 9.3 ± 2.9 Logistic euroscore 16.7 ± 11.3 Atrial fibrillation (%) 30.9% Aortic maximal velocity (m/s) 4.31 ± 0.67 Transaortic mean gradient (mmHg) 48.4 ± 13.9 AVA (cm2) 0.77 ± 0.3 AVAi (cm2/m2) 0.44 ± 0.2 EDVi (mL/m2) 64 ± 23.2 ESVi (mL/m2) 29.2 ± 17.6 Ejection fraction (%) 56.4 ± 11.3 Aortic regurgitation (%) 82.4% Mitral regurgitation (%) 95.9% STS, Society of Thoracic Surgeons; MM, morbidity&mortality; AVA, aortic valve area; EDV, end-diastolic volume; ESV, end-systolic volume. Among the 175 consecutive patients screened for TAVI in our centre, 26 did not undergo TAVI procedure for different reasons. Comparison of 3D manual, semi-automated, and MSCT measurements in overall population Excellent correlation between semi-automated and manual measurements was observed (Figure 2). There was no significative difference between the two methods for the minor diameter and area, whereas the semi-automated one measured bigger major diameters and smaller perimeters as compared to manual measurements (Table 2, Figure 3). Good agreement between semi-automated and manual measurements was found (Table 3, Figure 3). On average, 3D-TOE semi-automated software underestimated minor diameter, area, and perimeter as compared to manual measurements by 0.004%, 0.006%, and 0.03% respectively, whereas major diameter was overestimated by 0.05%. Table 2 Aortic annular measurements derived from different methods and imaging techniques 3D-TOE manual analysis 3D-TOE semi- automated software MSCT Overall population (n = 172)  Minor diameter (mm) 21.66 ± 2.4 21.58 ± 2.4 21.51 ± 2.6  Major diameter (mm) 23.91 ± 2.7*† 24.88 ± 2.81* 26.86 ± 2.8  Area (mm2) 428.4 ± 90.6* 426 ± 97.6* 444.1 ± 96.5  Perimeter (mm) 75.3 ± 7.8*† 73.3 ± 8.1* 76.6 ± 7.8 Subgroup: without calcific LVOT (n = 51)  Minor diameter(mm) 22.3 ± 2.38‡ 21.9 ± 2.66 21.7 ± 2.5  Major diameter (mm) 24.5 ± 2.9*‡ 25.2 ± 2.8* 27.3 ± 2.9  Area (mm2) 447.8 ± 98.6* 444 ± 97.7* 461.2 ± 99  Perimeter (mm) 76.9 ± 8.9*† 74.3 ± 8.4* 77.6 ± 8.6 Subgroup: calcific LVOT (n = 121)  Minor diameter (mm) 21.42 ± 2.44 21.46 ± 2.3 21.46 ± 2.6  Major diameter (mm) 23.7 ± 2.4*† 24.7 ± 2.8* 26.7 ± 2.8  Area (mm2) 421.4 ± 81.1* 417.5 ± 92.8* 437.9 ± 89.6  Perimeter (mm) 74.7 ± 7.2*† 72.9 ± 7.7* 76.2 ± 7.7 3D-TOE manual analysis 3D-TOE semi- automated software MSCT Overall population (n = 172)  Minor diameter (mm) 21.66 ± 2.4 21.58 ± 2.4 21.51 ± 2.6  Major diameter (mm) 23.91 ± 2.7*† 24.88 ± 2.81* 26.86 ± 2.8  Area (mm2) 428.4 ± 90.6* 426 ± 97.6* 444.1 ± 96.5  Perimeter (mm) 75.3 ± 7.8*† 73.3 ± 8.1* 76.6 ± 7.8 Subgroup: without calcific LVOT (n = 51)  Minor diameter(mm) 22.3 ± 2.38‡ 21.9 ± 2.66 21.7 ± 2.5  Major diameter (mm) 24.5 ± 2.9*‡ 25.2 ± 2.8* 27.3 ± 2.9  Area (mm2) 447.8 ± 98.6* 444 ± 97.7* 461.2 ± 99  Perimeter (mm) 76.9 ± 8.9*† 74.3 ± 8.4* 77.6 ± 8.6 Subgroup: calcific LVOT (n = 121)  Minor diameter (mm) 21.42 ± 2.44 21.46 ± 2.3 21.46 ± 2.6  Major diameter (mm) 23.7 ± 2.4*† 24.7 ± 2.8* 26.7 ± 2.8  Area (mm2) 421.4 ± 81.1* 417.5 ± 92.8* 437.9 ± 89.6  Perimeter (mm) 74.7 ± 7.2*† 72.9 ± 7.7* 76.2 ± 7.7 * P < 0.0001 vs. MSCT. † P < 0.0001 vs. 3D-TOE automated software analysis. ‡ P < 0.02 vs. 3D-TOE automated software analysis. Table 2 Aortic annular measurements derived from different methods and imaging techniques 3D-TOE manual analysis 3D-TOE semi- automated software MSCT Overall population (n = 172)  Minor diameter (mm) 21.66 ± 2.4 21.58 ± 2.4 21.51 ± 2.6  Major diameter (mm) 23.91 ± 2.7*† 24.88 ± 2.81* 26.86 ± 2.8  Area (mm2) 428.4 ± 90.6* 426 ± 97.6* 444.1 ± 96.5  Perimeter (mm) 75.3 ± 7.8*† 73.3 ± 8.1* 76.6 ± 7.8 Subgroup: without calcific LVOT (n = 51)  Minor diameter(mm) 22.3 ± 2.38‡ 21.9 ± 2.66 21.7 ± 2.5  Major diameter (mm) 24.5 ± 2.9*‡ 25.2 ± 2.8* 27.3 ± 2.9  Area (mm2) 447.8 ± 98.6* 444 ± 97.7* 461.2 ± 99  Perimeter (mm) 76.9 ± 8.9*† 74.3 ± 8.4* 77.6 ± 8.6 Subgroup: calcific LVOT (n = 121)  Minor diameter (mm) 21.42 ± 2.44 21.46 ± 2.3 21.46 ± 2.6  Major diameter (mm) 23.7 ± 2.4*† 24.7 ± 2.8* 26.7 ± 2.8  Area (mm2) 421.4 ± 81.1* 417.5 ± 92.8* 437.9 ± 89.6  Perimeter (mm) 74.7 ± 7.2*† 72.9 ± 7.7* 76.2 ± 7.7 3D-TOE manual analysis 3D-TOE semi- automated software MSCT Overall population (n = 172)  Minor diameter (mm) 21.66 ± 2.4 21.58 ± 2.4 21.51 ± 2.6  Major diameter (mm) 23.91 ± 2.7*† 24.88 ± 2.81* 26.86 ± 2.8  Area (mm2) 428.4 ± 90.6* 426 ± 97.6* 444.1 ± 96.5  Perimeter (mm) 75.3 ± 7.8*† 73.3 ± 8.1* 76.6 ± 7.8 Subgroup: without calcific LVOT (n = 51)  Minor diameter(mm) 22.3 ± 2.38‡ 21.9 ± 2.66 21.7 ± 2.5  Major diameter (mm) 24.5 ± 2.9*‡ 25.2 ± 2.8* 27.3 ± 2.9  Area (mm2) 447.8 ± 98.6* 444 ± 97.7* 461.2 ± 99  Perimeter (mm) 76.9 ± 8.9*† 74.3 ± 8.4* 77.6 ± 8.6 Subgroup: calcific LVOT (n = 121)  Minor diameter (mm) 21.42 ± 2.44 21.46 ± 2.3 21.46 ± 2.6  Major diameter (mm) 23.7 ± 2.4*† 24.7 ± 2.8* 26.7 ± 2.8  Area (mm2) 421.4 ± 81.1* 417.5 ± 92.8* 437.9 ± 89.6  Perimeter (mm) 74.7 ± 7.2*† 72.9 ± 7.7* 76.2 ± 7.7 * P < 0.0001 vs. MSCT. † P < 0.0001 vs. 3D-TOE automated software analysis. ‡ P < 0.02 vs. 3D-TOE automated software analysis. Table 3 Average bias and 95% limits of agreement for semi-automated and manual vs. MSCT aortic annulus measurements obtained by the Bland–Altman analysis Overall population (n = 172) Subgroup without LVOT calcification (n = 51) Subgroup with LVOT calcification (n = 121) Average bias (95% CI) Average bias (95% CI) Average bias (95% CI) Software Manual Manual vs. software Software Manual Manual vs. software Software Manual Manual vs. software Minor diameter (mm) 0.07 (−0.2 to 0.4) 0.15 (−0.2 to 0.4) 0.08 (−0.1 to 0.8) 0.2 (−0.2 to 0.8) 0.6 (0.2 to 1) 0.4 (0.1 to 0.7) 0 (0.34 to −0.38) −0.04 (−0.4 to 0.2) −0.04 (−0.3 to 0.19) Major diameter (mm) −1.98 (−2.3 to −1.6) −2.9 (−3.2 to −2.6) −0.9 (−1.7 to −0.2) −2.1 (2.6 to −1.4) −2.8 (−3.3 to −2.0) −0.7 (−1.2 to −0.2) −2 (−2.3 to −1.5) −2.98 (−3.3 to −2.6) −1 (−1.4 to −0.7) Area (mm2) −18.08 (−26.5 to −9.6) −15.7 (−24.4 to −7) 2.4 (−4.7 to 9.4) −17.2 (−27 to −7.46) −13.4 (−32 to −5) 3.8 (−5 to 9.1) −20.4 (−37.1 to −3.3) −16.5 (−26 to −6.3) 3.9 (−7.9 to 9) Perimeter (mm) −3.3 (−4.0 to −2.5) − 1.3 (−2.1 to −0.5) 2 (1.5 to 2.7) −3.3 (−4.8 to −1.8) −0.7 (−2.1 to −0.8) 2.6 (1.8 to 3.9) −3.3 (−4.2 to −2.4) −1.5 (−2.5 to −0.5) 1.8 (1.1 to 2.6) Overall population (n = 172) Subgroup without LVOT calcification (n = 51) Subgroup with LVOT calcification (n = 121) Average bias (95% CI) Average bias (95% CI) Average bias (95% CI) Software Manual Manual vs. software Software Manual Manual vs. software Software Manual Manual vs. software Minor diameter (mm) 0.07 (−0.2 to 0.4) 0.15 (−0.2 to 0.4) 0.08 (−0.1 to 0.8) 0.2 (−0.2 to 0.8) 0.6 (0.2 to 1) 0.4 (0.1 to 0.7) 0 (0.34 to −0.38) −0.04 (−0.4 to 0.2) −0.04 (−0.3 to 0.19) Major diameter (mm) −1.98 (−2.3 to −1.6) −2.9 (−3.2 to −2.6) −0.9 (−1.7 to −0.2) −2.1 (2.6 to −1.4) −2.8 (−3.3 to −2.0) −0.7 (−1.2 to −0.2) −2 (−2.3 to −1.5) −2.98 (−3.3 to −2.6) −1 (−1.4 to −0.7) Area (mm2) −18.08 (−26.5 to −9.6) −15.7 (−24.4 to −7) 2.4 (−4.7 to 9.4) −17.2 (−27 to −7.46) −13.4 (−32 to −5) 3.8 (−5 to 9.1) −20.4 (−37.1 to −3.3) −16.5 (−26 to −6.3) 3.9 (−7.9 to 9) Perimeter (mm) −3.3 (−4.0 to −2.5) − 1.3 (−2.1 to −0.5) 2 (1.5 to 2.7) −3.3 (−4.8 to −1.8) −0.7 (−2.1 to −0.8) 2.6 (1.8 to 3.9) −3.3 (−4.2 to −2.4) −1.5 (−2.5 to −0.5) 1.8 (1.1 to 2.6) Table 3 Average bias and 95% limits of agreement for semi-automated and manual vs. MSCT aortic annulus measurements obtained by the Bland–Altman analysis Overall population (n = 172) Subgroup without LVOT calcification (n = 51) Subgroup with LVOT calcification (n = 121) Average bias (95% CI) Average bias (95% CI) Average bias (95% CI) Software Manual Manual vs. software Software Manual Manual vs. software Software Manual Manual vs. software Minor diameter (mm) 0.07 (−0.2 to 0.4) 0.15 (−0.2 to 0.4) 0.08 (−0.1 to 0.8) 0.2 (−0.2 to 0.8) 0.6 (0.2 to 1) 0.4 (0.1 to 0.7) 0 (0.34 to −0.38) −0.04 (−0.4 to 0.2) −0.04 (−0.3 to 0.19) Major diameter (mm) −1.98 (−2.3 to −1.6) −2.9 (−3.2 to −2.6) −0.9 (−1.7 to −0.2) −2.1 (2.6 to −1.4) −2.8 (−3.3 to −2.0) −0.7 (−1.2 to −0.2) −2 (−2.3 to −1.5) −2.98 (−3.3 to −2.6) −1 (−1.4 to −0.7) Area (mm2) −18.08 (−26.5 to −9.6) −15.7 (−24.4 to −7) 2.4 (−4.7 to 9.4) −17.2 (−27 to −7.46) −13.4 (−32 to −5) 3.8 (−5 to 9.1) −20.4 (−37.1 to −3.3) −16.5 (−26 to −6.3) 3.9 (−7.9 to 9) Perimeter (mm) −3.3 (−4.0 to −2.5) − 1.3 (−2.1 to −0.5) 2 (1.5 to 2.7) −3.3 (−4.8 to −1.8) −0.7 (−2.1 to −0.8) 2.6 (1.8 to 3.9) −3.3 (−4.2 to −2.4) −1.5 (−2.5 to −0.5) 1.8 (1.1 to 2.6) Overall population (n = 172) Subgroup without LVOT calcification (n = 51) Subgroup with LVOT calcification (n = 121) Average bias (95% CI) Average bias (95% CI) Average bias (95% CI) Software Manual Manual vs. software Software Manual Manual vs. software Software Manual Manual vs. software Minor diameter (mm) 0.07 (−0.2 to 0.4) 0.15 (−0.2 to 0.4) 0.08 (−0.1 to 0.8) 0.2 (−0.2 to 0.8) 0.6 (0.2 to 1) 0.4 (0.1 to 0.7) 0 (0.34 to −0.38) −0.04 (−0.4 to 0.2) −0.04 (−0.3 to 0.19) Major diameter (mm) −1.98 (−2.3 to −1.6) −2.9 (−3.2 to −2.6) −0.9 (−1.7 to −0.2) −2.1 (2.6 to −1.4) −2.8 (−3.3 to −2.0) −0.7 (−1.2 to −0.2) −2 (−2.3 to −1.5) −2.98 (−3.3 to −2.6) −1 (−1.4 to −0.7) Area (mm2) −18.08 (−26.5 to −9.6) −15.7 (−24.4 to −7) 2.4 (−4.7 to 9.4) −17.2 (−27 to −7.46) −13.4 (−32 to −5) 3.8 (−5 to 9.1) −20.4 (−37.1 to −3.3) −16.5 (−26 to −6.3) 3.9 (−7.9 to 9) Perimeter (mm) −3.3 (−4.0 to −2.5) − 1.3 (−2.1 to −0.5) 2 (1.5 to 2.7) −3.3 (−4.8 to −1.8) −0.7 (−2.1 to −0.8) 2.6 (1.8 to 3.9) −3.3 (−4.2 to −2.4) −1.5 (−2.5 to −0.5) 1.8 (1.1 to 2.6) Figure 2 View largeDownload slide Correlations between manual and semi-automated software in overall population and in the two subgroups with and without LVOT calcification. Figure 2 View largeDownload slide Correlations between manual and semi-automated software in overall population and in the two subgroups with and without LVOT calcification. Figure 3 View largeDownload slide The Bland–Altman plots for AA measurements by manual and semi-automated software in overall population and in the subgroups with and without LVOT calcification. Figure 3 View largeDownload slide The Bland–Altman plots for AA measurements by manual and semi-automated software in overall population and in the subgroups with and without LVOT calcification. Good correlation between both semi-automated and manual measurements vs. MSCT was observed (Figure 4). Except for the minor diameter (sagittal diameter), the semi-automated and manual measurements significantly underestimated the major diameter (coronal diameter), area, and the perimeter (Table 2). Figure 4 View largeDownload slide Correlations between 3D-TOE and MSCT measurements in overall population. Figure 4 View largeDownload slide Correlations between 3D-TOE and MSCT measurements in overall population. Good agreement between both semi-automated and manual measurements vs. MSCT was found (Table 3, Figure 5). On average, 3D-TOE semi-automated software underestimated major diameter, area, and perimeter compared to MSCT measurements by 7.4%, 3.5%, and 4.4% respectively, whereas minor diameter was overestimated by 0.3% and 3D-TOE manual measurements by 11%, 2.9%, and 1.7%, respectively, whereas minor diameter was overestimated by 0.5%. Figure 5 View largeDownload slide The Bland–Altman plots for minor and major diameters, area, and perimeter by manual, semi-automated, and MSCT measurements in overall population. Figure 5 View largeDownload slide The Bland–Altman plots for minor and major diameters, area, and perimeter by manual, semi-automated, and MSCT measurements in overall population. 3D-TOE-derived semi-automated software major diameter and area showed narrower limits of agreement and smaller bias compared to manual ones, whereas 3D-TOE software-derived perimeter showed only narrower limits of agreement than manual analysis as illustrated by the Bland–Altman Plot (Figure 5). The mean time required for the AA analysis was 50 ± 7 s and 205 ± 39 s by the semi-automated and manual analysis, respectively (P = 0.001), leading to an average time-saving of 155 ± 41 s per analysis. Subgroup analysis Patients without LVOT calcification (n = 51, 28%) Excellent correlation between both semi-automated and manual measurements was found (Figure 2). There was no difference between 3D semi-automated software and manual analysis with regard to area, whereas 3D semi-automated showed slightly smaller AA minor diameter and perimeter and bigger major diameter (Table 2). Good agreement between semi-automated and manual measurements was observed (Table 3, Figure 3). Good correlation between both semi-automated and manual measurements vs. MSCT was found (Figure 6). With the exception of AA minor diameter, 3D semi-automated and manual measurements significantly underestimate the major diameter, AA area, and perimeter (Table 2). Good agreement between both semi-automated and manual measurements vs. MSCT was observed (Table 3). 3D-TOE-derived software major diameter and area had narrower limits of agreement and least bias than manual ones, whereas 3D-TOE-derived software perimeter showed only narrowest limits of agreements than manual one (Table 3). Figure 6 View largeDownload slide Correlations in the subgroup of patients without LVOT calcification. Figure 6 View largeDownload slide Correlations in the subgroup of patients without LVOT calcification. Patients with LVOT calcification (n = 121, 70%) The correlation between the measurements obtained by the automated and manual analysis was good (Figure 2), as well as good agreement between the two methods was found (Table 3, Figure 3). There was no significative difference between the two methods for the minor diameter and area, whereas the semi-automated software has bigger major diameters and smaller perimeters as compared to manual measurements (Table 2, Figure 3). Similarly, the correlation between the measurements obtained by the automated and manual analysis vs. MSCT was good (Figure 7), as well as good agreement between techniques was found (Table 3). Except for the minor diameter, 3D semi-automated and manual measurements significantly underestimated the major diameter, area, and perimeter (Table 2). Finally, 3D-TOE-derived semi-automated major diameter and area had narrower limits of agreement and least bias than manual ones, whereas 3D-TOE-derived software perimeter showed only narrowest limits of agreements than manual ones (Table 3). Figure 7 View largeDownload slide Correlations in subgroup of patients with LVOT calcification. Figure 7 View largeDownload slide Correlations in subgroup of patients with LVOT calcification. Hypothetical prosthesis sizing selection When we tested the agreement between 3D manual and semi-automated methods vs. MSCT regarding the hypothetical prosthesis sizing to be implanted, a moderate agreement for both techniques was found: 96/149 (64%) patients, Kappa agreement 0.5, and 97/149 (65%) patients, Kappa agreement 0.5 for automatic and manual analysis, respectively. The discrepancy between the two imaging modalities in prosthesis sizing selection is more remarkable for the intermediate sizes than for the ends (Figure 8). Figure 8 View largeDownload slide Discrepancy in THV sizing according to 3D-TOE vs. CT measurement, for 3D-TOE software in Panel A and 3D-TOE manual analysis in Panel B. THV, transcatheter heart valve. Figure 8 View largeDownload slide Discrepancy in THV sizing according to 3D-TOE vs. CT measurement, for 3D-TOE software in Panel A and 3D-TOE manual analysis in Panel B. THV, transcatheter heart valve. Interobserver and intraobserver variability Interobserver and intraobserver ICCs and biases were excellent for all measurements for both techniques (manual and semi-automated) (Table 4). Table 4 Inter- and intra-observer variability Variable 3D-TOE manual analysis 3D-TOE semi-automated analysis Intraobserver Interobserver Intraobserver Interobserver Minor diameter (mm) ICC: 0.91* ICC: 0.87* ICC: 0.93* ICC: 0.92* Bias: −0.06 (−0.3 to 0.2) Bias: 0.51 (0.19 to 0.83) Bias: −0.1 (−0.4 to 0.08) Bias: −0.3 (−0.5 to 0.05) Major diameter (mm) ICC: 0.94* ICC: 0.92* ICC: 0.93* ICC: 0.90* Bias: −0.11 (−0.4 to 0.1) Bias: 0.14 (−0.1 to 0.49) Bias: −0.08 (−0.4 to 0.2) Bias: −0.08 (−0.4 to 0.3) Area (mm2) ICC: 0.92* ICC: 0.91* ICC: 0.94* ICC: 0.92* Bias: −6.7 (−17.3 to 3.9) Bias: −9.7 (−17.2 to −2.2) Bias: −5.7 (−14.6 to 3.2) Bias: −7.6 (−15.2 to −0.1) Perimeter (mm) ICC: 0.94* ICC: 0.88* ICC: 0.96* ICC: 0.91* Bias: −0.6 (−1.3 to 0.1) Bias: −0.8 (−1.3 to 0.8) Bias: −0.3 (−0.9 to 0.3) Bias: −0.8 (−1.7 to −0.0) Variable 3D-TOE manual analysis 3D-TOE semi-automated analysis Intraobserver Interobserver Intraobserver Interobserver Minor diameter (mm) ICC: 0.91* ICC: 0.87* ICC: 0.93* ICC: 0.92* Bias: −0.06 (−0.3 to 0.2) Bias: 0.51 (0.19 to 0.83) Bias: −0.1 (−0.4 to 0.08) Bias: −0.3 (−0.5 to 0.05) Major diameter (mm) ICC: 0.94* ICC: 0.92* ICC: 0.93* ICC: 0.90* Bias: −0.11 (−0.4 to 0.1) Bias: 0.14 (−0.1 to 0.49) Bias: −0.08 (−0.4 to 0.2) Bias: −0.08 (−0.4 to 0.3) Area (mm2) ICC: 0.92* ICC: 0.91* ICC: 0.94* ICC: 0.92* Bias: −6.7 (−17.3 to 3.9) Bias: −9.7 (−17.2 to −2.2) Bias: −5.7 (−14.6 to 3.2) Bias: −7.6 (−15.2 to −0.1) Perimeter (mm) ICC: 0.94* ICC: 0.88* ICC: 0.96* ICC: 0.91* Bias: −0.6 (−1.3 to 0.1) Bias: −0.8 (−1.3 to 0.8) Bias: −0.3 (−0.9 to 0.3) Bias: −0.8 (−1.7 to −0.0) Bias was obtained using the Bland–Altman analysis with 95% CI. * P < 0.001. Table 4 Inter- and intra-observer variability Variable 3D-TOE manual analysis 3D-TOE semi-automated analysis Intraobserver Interobserver Intraobserver Interobserver Minor diameter (mm) ICC: 0.91* ICC: 0.87* ICC: 0.93* ICC: 0.92* Bias: −0.06 (−0.3 to 0.2) Bias: 0.51 (0.19 to 0.83) Bias: −0.1 (−0.4 to 0.08) Bias: −0.3 (−0.5 to 0.05) Major diameter (mm) ICC: 0.94* ICC: 0.92* ICC: 0.93* ICC: 0.90* Bias: −0.11 (−0.4 to 0.1) Bias: 0.14 (−0.1 to 0.49) Bias: −0.08 (−0.4 to 0.2) Bias: −0.08 (−0.4 to 0.3) Area (mm2) ICC: 0.92* ICC: 0.91* ICC: 0.94* ICC: 0.92* Bias: −6.7 (−17.3 to 3.9) Bias: −9.7 (−17.2 to −2.2) Bias: −5.7 (−14.6 to 3.2) Bias: −7.6 (−15.2 to −0.1) Perimeter (mm) ICC: 0.94* ICC: 0.88* ICC: 0.96* ICC: 0.91* Bias: −0.6 (−1.3 to 0.1) Bias: −0.8 (−1.3 to 0.8) Bias: −0.3 (−0.9 to 0.3) Bias: −0.8 (−1.7 to −0.0) Variable 3D-TOE manual analysis 3D-TOE semi-automated analysis Intraobserver Interobserver Intraobserver Interobserver Minor diameter (mm) ICC: 0.91* ICC: 0.87* ICC: 0.93* ICC: 0.92* Bias: −0.06 (−0.3 to 0.2) Bias: 0.51 (0.19 to 0.83) Bias: −0.1 (−0.4 to 0.08) Bias: −0.3 (−0.5 to 0.05) Major diameter (mm) ICC: 0.94* ICC: 0.92* ICC: 0.93* ICC: 0.90* Bias: −0.11 (−0.4 to 0.1) Bias: 0.14 (−0.1 to 0.49) Bias: −0.08 (−0.4 to 0.2) Bias: −0.08 (−0.4 to 0.3) Area (mm2) ICC: 0.92* ICC: 0.91* ICC: 0.94* ICC: 0.92* Bias: −6.7 (−17.3 to 3.9) Bias: −9.7 (−17.2 to −2.2) Bias: −5.7 (−14.6 to 3.2) Bias: −7.6 (−15.2 to −0.1) Perimeter (mm) ICC: 0.94* ICC: 0.88* ICC: 0.96* ICC: 0.91* Bias: −0.6 (−1.3 to 0.1) Bias: −0.8 (−1.3 to 0.8) Bias: −0.3 (−0.9 to 0.3) Bias: −0.8 (−1.7 to −0.0) Bias was obtained using the Bland–Altman analysis with 95% CI. * P < 0.001. Discussion The present study demonstrates that: (i) 3D-TOE semi-automated software analysis of AA is: feasible; reliable with a good correlation between 3D-TOE and MSCT measurements; and reproducible with a low intra- and inter-observer variability; (ii) 3D-TOE manual and semi-automated analysis underestimate the major diameter, area, and perimeter compared to respective MSCT measurements; (iii) using MSCT as the ‘gold standard’, 3D-TOE semi-automated measurements showed slightly better correlations, the least underestimation, and narrowest limits of agreements for most of the parameters compared with their respective manual ones; (iv) moderate agreement between manual, semi-automated, and MSCT measurements regarding prosthesis sizing selection was found. Accurate measurements of AA are essential for pre-procedural TAVI planning and non-invasive imaging modalities play an important role in this setting. MSCT cross-sectional area and perimeter are considered the gold standard for AA sizing before TAVI. Numerous studies have shown the advantages of 3D assessment of the annulus compared with 2D assessment using multiple modalities, including MSCT,5,6,13 3D-TOE,14–17 and cardiac MRI.5 Cross-sectional 3D-TOE annulus measurements generally underestimate the MSCT ones.7,9,16 An error in the range of 10% that was found in previous published reports could be clinically significant and potentially dangerous for the patient. The current study shows good correlation between 3D-TOE methods and MSCT, and smaller error range by 3D-TOE manual and semi-automated analysis than observed in previous studies. Novel automated 3D-TOE reconstruction tools have recently been introduced, performing automated reconstruction and analysis of the aortic root starting from data set using a pre-defined algorithm.10 The current study suggests that the measurements obtained with this software are accurate and highly correlative with MSCT ones with excellent interobserver and intraobserver variability. Semi-automated analysis shows slightly better correlations with MSCT measurements, narrower limits of agreement and lesser bias than manual measurements. It is less time-consuming than manual analysis, at least two and a half minutes per analysis time-saving. The software seems to have good performance in both patients without and with LVOT calcifications. Furthermore, the operator can adjust the axes and the automatic tracking. Therefore, the software should be referred as ‘3D-TOE semi-automated’ application and not ‘automated’: that could be the reason why it performed better than manual analysis made by experienced cardiologists. However, Khalique et al.9 by the off-label use of 3D-TOE software obtained excellent correlation between 3D-TOE and MSCT measurements and smaller absolute differences (≤1%) than those obtained in our study. As suggested in the study by Tsang et al.,18 3D-TOE and MSCT clearly have different imaging limitations that may lead to the selection of slightly different transverse planes for annulus assessment. In addition, ectopic calcification may introduce significant measurement errors that differ by techniques. Indeed, in our patients without LVOT calcification, we observed a slight increase of the correlation and the least bias between 3D-TOE and MSCT measurements both with manual and automatic software analyses. The two modalities also differ in temporal resolution, thus measurements may be performed in slightly different points in the cardiac cycle.19 Moreover we know that generally, the annular size (mean diameter) as measured by TOE is smaller when compared MSCT measurement in mid-systole.20 Since we measured in mid-systole for 3D-TOE and in mid-diastole for MSCT, our findings could reflect these overall differences between the two modalities. Finally, 3D-TOE and MSCT have distinct strengths and weaknesses. 3D-TOE has superior temporal resolution, which often allows for differentiation of the basal aortic valve hinge point on the basis of visualized separation of calcium, and essentially eliminates motion-based artefacts. However, 3D-TOE is limited by suboptimal lateral resolution in the coronal plane, which reduces the ability to measure the blood/tissue interface in this plane, particularly in case of ectopic calcification (the coronal diameter, indeed, shows the least underestimation and the worst correlations) (Figure 9). On the contrary, MSCT typically provides superior tissue/lumen contrast but may be limited by artefacts because of partial volume-averaging effects (blooming), heart/lung motion, patient motion, and arrhythmias. Figure 9 View largeDownload slide Determination of annulus size by 3D-TOE in patients without (Panels A and B) and with LVOT calcification (Panels B and C, white arrows). 3D reconstructions are affected by suboptimal lateral resolution in the coronal plane (red arrows), which reduces the ability to measure the blood/tissue interface in this plane, particularly in case of ectopic calcification (Panel C). Figure 9 View largeDownload slide Determination of annulus size by 3D-TOE in patients without (Panels A and B) and with LVOT calcification (Panels B and C, white arrows). 3D reconstructions are affected by suboptimal lateral resolution in the coronal plane (red arrows), which reduces the ability to measure the blood/tissue interface in this plane, particularly in case of ectopic calcification (Panel C). We assessed the clinical implications of 3D-TOE AA measurements on the prosthesis sizing selection. We found a moderate agreement between manual and automatic measurements vs. manufacturer-recommended CT-based sizing algorithm. Among the 35% of discordance, 3D-TOE measurements lead to prosthesis underestimation in most of the cases. These findings could be explained by several factors affecting prosthesis sizing selection. Indeed, the degree of calcification and an elliptic shape of AA establish whether to oversize or undersize the prosthesis. Therefore, in case the prosthesis sizing should be selected only on the basis of the 3D-TOE measurements, we might speculate that it is necessary to apply a correction factor of overestimation with respect to the manufacturer-recommended CT-based sizing algorithm. This overestimation may be the same average difference between the measurements observed in our study according to the presence or the absence of LVOT calcification. This software could be used alternatively to MSCT in particular settings such as for contrast nephrotoxicity avoidance, which is especially important if we consider that TAVI candidates are usually elderly people with high risk of renal failure, or in patients with severe allergy to ionidated contrast or in cases of arrhythmias that makes ECG gating difficult for MSCT acquisition. However, MSCT offers a wide range of information for pre-procedural screening including the exact delineation of the access rout which is crucial for transfemoral vs. transapical selection, the evaluation of the distance of the coronary ostia from AA and the exact location and amount of valvular calcifications. Limitations The study is a single-centre observational study, in which pre-procedural MSCT and 3D-TOE were used for AA evaluation, but final prosthesis size was decided only on the basis of CT measurement: 3D-TOE-based prosthesis sizing was performed retrospectively by only one TAVI operator in blinded fashion. The high reproducibility of these measurements is likely dependent on training and experience, and thus our findings cannot necessarily be generalized to less-experienced readers. Finally, both modalities are user dependent, and optimal image acquisition and analysis are always paramount for adequate annular assessment. Given these differences, echocardiography and MSCT have to be considered as complementary imaging modalities. Conclusions Our results support the use of the semi-automated software in clinical practice, which could be an alternative to MSCT for the pre-procedural assessment of AA. 3D-TOE may be a valuable tool for prosthetic sizing in patients where MSCT is not feasible or desirable, such as in the setting of significant renal impairment, or in patients in whom MSCT was not reliable enough for pre-procedural planning, due to poor imaging quality. References 1 Vahanian A , Alfieri O , Andreotti F , Antunes MJ , Baron-Esquivias G , Baumgartner H et al. Guidelines on the management of valvular heart disease (version 2012) The Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European . Eur Heart J 2012 ; 33 : 2451 – 96 . Google Scholar CrossRef Search ADS PubMed 2 Leon MB , Smith CR , Mack MJ , Makkar RR , Svensson LG , Kodali SK et al. Transcatheter or surgical aortic-valve replacement in intermediate-risk patients . N Engl J Med 2016 ; 374 : 1609 – 20 . Google Scholar CrossRef Search ADS PubMed 3 Moss RR , Ivens E , Pasupati S , Humphries K , Thompson CR , Munt B et al. Role of echocardiography in percutaneous aortic valve implantation . JACC Cardiovasc Imaging 2008 ; 1 : 15 – 24 . Google Scholar CrossRef Search ADS PubMed 4 Leipsic J , Gurvitch R , Labounty TM , Min JK , Wood D , Johnson M et al. Multidetector computed tomography in transcatheter aortic valve implantation . JACC Cardiovasc Imaging 2011 ; 4 : 416 – 29 . Google Scholar CrossRef Search ADS PubMed 5 Koos R , Altiok E , Mahnken AH , Neizel M , Dohmen G , Marx N et al. Evaluation of aortic root for definition of prosthesis size by magnetic resonance imaging and cardiac computed tomography: implications for transcatheter aortic valve implantation . Int J Cardiol 2012 ; 158 : 353 – 8 . Google Scholar CrossRef Search ADS PubMed 6 Altiok E , Koos R , Schröder J , Brehmer K , Hamada S , Becker M et al. Comparison of two-dimensional and three-dimensional imaging techniques for measurement of aortic annulus diameters before transcatheter aortic valve implantation . Heart 2011 ; 97 : 1578 – 84 . Google Scholar CrossRef Search ADS PubMed 7 Schultz CJ , Moelker A , Piazza N , Tzikas A , Otten A , Nuis RJ et al. Three dimensional evaluation of the aortic annulus using multislice computer tomography: are manufacturer’s guidelines for sizing for percutaneous aortic valve replacement helpful? Eur Heart J 2010 ; 31 : 849 – 56 . Google Scholar CrossRef Search ADS PubMed 8 Ng ACT , Delgado V , Van Der Kley F , Shanks M , Van De Veire NRL , Bertini M et al. Comparison of aortic root dimensions and geometries before and after transcatheter aortic valve implantation by 2-and 3-dimensional transesophageal echocardiography and multislice computed tomography . Circ Cardiovasc Imaging 2010 ; 3 : 94 – 102 . Google Scholar CrossRef Search ADS PubMed 9 Khalique OK , Kodali SK , Paradis JM , Nazif TM , Williams MR , Einstein AJ et al. Aortic annular sizing using a novel 3-dimensional echocardiographic method use and comparison with cardiac computed tomography . Circ Cardiovasc Imaging 2014 ; 7 : 155 – 63 . Google Scholar CrossRef Search ADS PubMed 10 García-Martín A , Lázaro-Rivera C , Fernández-Golfín C , Salido-Tahoces L , Moya-Mur J-L , Jiménez-Nacher J-J et al. Accuracy and reproducibility of novel echocardiographic three-dimensional automated software for the assessment of the aortic root in candidates for transcatheter aortic valve replacement . Eur Heart J Cardiovasc Imaging 2016 ; 17 : 772 – 8 . Google Scholar CrossRef Search ADS PubMed 11 Zamorano JL , Badano LP , Bruce C , Chan K-L , Goncalves A , Hahn RT et al. EAE/ASE recommendations for the use of echocardiography in new transcatheter interventions for valvular heart disease . Eur Heart J 2011 ; 32 : 2189 – 214 . Google Scholar CrossRef Search ADS PubMed 12 Spagnolo P , Giglio M , Di Marco D , Latib A , Besana F , Chieffo A et al. Feasibility of ultra-low contrast 64-slice computed tomography angiography before transcatheter aortic valve implantation: a real-world experience . Eur Heart J Cardiovasc Imaging 2016 ; 17 : 24 – 33 . Google Scholar CrossRef Search ADS PubMed 13 Bloomfield GS , Gillam LD , Hahn RT , Kapadia S , Leipsic J , Lerakis S et al. A practical guide to multimodality imaging of transcatheter aortic valve replacement . JACC Cardiovasc Imaging 2012 ; 5 : 441 – 55 . Google Scholar CrossRef Search ADS PubMed 14 Janosi RA , Kahlert P , Plicht B , Wendt D , Eggebrecht H , Erbel R et al. Measurement of the aortic annulus size by real-time three-dimensional transesophageal echocardiography . Minim Invasive Ther Allied Technol 2011 ; 20 : 85 – 94 . Google Scholar CrossRef Search ADS PubMed 15 Santos N , De Agustín JA , Almería C , Gonçalves A , Marcos-Alberca P , Fernández-Golfín C et al. Prosthesis/annulus discongruence assessed by three-dimensional transoesophageal echocardiography: a predictor of significant paravalvular aortic regurgitation after transcatheter aortic valve implantation . Eur Heart J Cardiovasc Imaging 2012 ; 13 : 931 – 7 . Google Scholar CrossRef Search ADS PubMed 16 Jilaihawi H , Doctor N , Kashif M , Chakravarty T , Rafique A , Makar M et al. Aortic annular sizing for transcatheter aortic valve replacement using cross-sectional 3-dimensional transesophageal echocardiography . J Am Coll Cardiol 2013 ; 61 : 908 – 16 . Google Scholar CrossRef Search ADS PubMed 17 Shahgaldi K , da Silva C , Bäck M , Rück A , Manouras A , Sahlén A. Transesophageal echocardiography measurements of aortic annulus diameter using biplane mode in patients undergoing transcatheter aortic valve implantation . Cardiovasc Ultrasound 2013 ; 11 : 5 . Google Scholar CrossRef Search ADS PubMed 18 Tsang W , Bateman MG , Weinert L , Pellegrini G , Mor-Avi V , Sugeng L et al. Accuracy of aortic annular measurements obtained from three-dimensional echocardiography, CT and MRI: human in vitro and in vivo studies . Heart 2012 ; 98 : 1146 – 52 . Google Scholar CrossRef Search ADS PubMed 19 Schultz CJ , Moelker AD , Tzikas A , Rossi A , Van Geuns RJ , De Feyter PJ et al. Cardiac CT: necessary for precise sizing for transcatheter aortic implantation . EuroIntervention 2010 ; 6 (Suppl G): G6 – 13 . Google Scholar CrossRef Search ADS PubMed 20 Husser O , Rauch S , Endemann DH , Resch M , Nunez J , Bodi V et al. Impact of three-dimensional transesophageal echocardiography on prosthesis sizing for transcatheter aortic valve implantation . Catheter Cardiovasc Interv 2012 ; 80 : 956 – 63 . Google Scholar CrossRef Search ADS PubMed Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png European Heart Journal – Cardiovascular Imaging Oxford University Press

Accuracy and reproducibility of aortic annular measurements obtained from echocardiographic 3D manual and semi-automated software analyses in patients referred for transcatheter aortic valve implantation: implication for prosthesis size selection

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Oxford University Press
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Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.
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2047-2404
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10.1093/ehjci/jey013
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Abstract

Abstract Aims A 3D transoesophageal echocardiography (3D-TOE) reconstruction tool has recently been introduced. The system automatically configures a geometric model of the aortic root and performs quantitative analysis of these structures. We compared the measurements of the aortic annulus (AA) obtained by semi-automated 3D-TOE quantitative software and manual analysis vs. multislice computed tomography (MSCT) ones. Methods and results One hundred and seventy-five patients (mean age 81.3 ± 6.3 years, 77 men) who underwent both MSCT and 3D-TOE for annulus assessment before transcatheter aortic valve implantation were analysed. Hypothetical prosthetic valve sizing was evaluated using the 3D manual, semi-automated measurements using manufacturer-recommended CT-based sizing algorithm as gold standard. Good correlation between 3D-TOE methods vs. MSCT measurements was found, but the semi-automated analysis demonstrated slightly better correlations for AA major diameter (r = 0.89), perimeter (r = 0.89), and area (r = 0.85) (all P < 0.0001) than manual one. Both 3D methods underestimated the MSCT measurements, but semi-automated measurements showed narrower limits of agreement and lesser bias than manual measurements for most of AA parameters. On average, 3D-TOE semi-automated major diameter, area, and perimeter underestimated the respective MSCT measurements by 7.4%, 3.5%, and 4.4%, respectively, whereas minor diameter was overestimated by 0.3%. Moderate agreement for valve sizing for both 3D-TOE techniques was found: Kappa agreement 0.5 for both semi-automated and manual analysis. Interobserver and intraobserver agreements for the AA measurements were excellent for both techniques (intraclass correlation coefficients for all parameters >0.80). Conclusion The 3D-TOE semi-automated analysis of AA is feasible and reliable and can be used in clinical practice as an alternative to MSCT for AA assessment. transcatheter aortic valve replacement, 3D transoesophageal echocardiography, 3D echocardiographic semi-automated software, aortic annular sizing Introduction Transcatheter aortic valve implantation (TAVI) is nowadays an alternative therapeutic option in patients with severe symptomatic aortic stenosis (AS) at high or intermediate surgical risk or with contraindication to surgery.1,2 Accurate imaging assessment of the aortic valve annulus (AA) is critical for prosthesis sizing. Several imaging techniques have been used for this purpose.3–5 2D echocardiographic images allow the analysis of the annulus diameter in just one view (sagittal plane) and may underestimate the maximal valve annulus diameter.6 Multislice computed tomography (MSCT) achieved a central role in the pre-procedural planning providing also information about the degree of valve calcification and the morphology of the access routes.7 3D transoesophageal echocardiography (3D-TOE) is a safe procedure that does not require iodinated contrast and may constitute a valuable imaging tool during TAVI, providing accurate measurements of the aortic root and geometry. Recent studies suggest that the annulus measurements using 3D-TOE images closely approximate those of MSCT.8,9 3D-TOE reconstruction tools have recently been introduced, which automatically configures a geometric model of the aortic root from the images obtained by 3D-TOE and perform quantitative analyses of the AA.10 However, the accuracy of these methods compared with the standard imaging techniques has not been completely evaluated yet. The aims of this study were: (i) to compare the measurements of the AA obtained by semi-automated quantitative modelling of the root from 3D-TOE data to those obtained by 3D-TOE manual analysis and by MSCT as the ‘gold standard’; (ii) to determine agreements between 3D-TOE manual, semi-automated, and MSCT-derived AA measurements; and (iii) to assess the reproducibility of the methods. Methods Study population From October 2014 to August 2016, 175 consecutive patients with severe symptomatic AS eligible for TAVI in our institution were enrolled in the study and underwent both 3D-TOE and MSCT as part of our TAVI screening protocol. This protocol includes a comprehensive transthoracic and TOE echocardiographic assessment, including 3D-TOE, and MSCT. Three patients did not undergo MSCT due to renal failure. All patients signed informed consent for the diagnostic and therapeutic procedures. Echocardiographic examinations All patients underwent both transthoracic and TOE examination using GE Vivid E9 (GE Healthcare, Milwaukee, WI, USA) ultrasound system equipped with MS5 and 6VT-D probes respectively. A complete 2D, colour, pulsed, and continuous-wave Doppler echocardiogram was performed according to EACVI recommendations.11 Mean transaortic pressure gradient was measured by continuous-wave Doppler, and aortic valve area was calculated by the continuity equation. Furthermore, the distribution of calcifications was determined using a qualitative evaluation by assessing the presence of calcifications from the leaflet tips to the left ventricular outflow tract (LVOT) and focusing on the calcification protruding into LVOT from the annular level. 3D semi-automated aortic annulus measurements Images were taken from a mid-oesophageal position. The 2D image was centred on the aortic valve including 2–4 cm of the LVOT and aortic root in the sector. A zoomed image acquisition modality (electrocardiographically triggered multiple-beat 3D imaging was preferred) was used avoiding stitching artefacts, at a minimum frame rate of 12 fps (minimum frame rate required for semi-automated software analysis). The 3D data sets were digitally stored and transferred on external workstation for offline analysis (EchoPAC version 201). The system automatically aligns the images, but manual correction might be necessary. A mid-systolic frame with the aortic valve fully opened is automatically selected. The image is aligned properly around the centre lines as follows (Figure 1A): Figure 1 View largeDownload slide Measurements of the aortic root obtained by different methods. (A) 4D auto-aortic valve quantification. 1: automatic assessment of the three orthogonal plane, 2: automatic tracking of LVOT, aortic annulus, and aortic root; 3: automatic trace of the LVOT, aortic annulus, and aortic root borders; 4: tracking’s manual modification; 5: optimized tracking. (B) 3D-TOE manual multiplanar reformations of the aortic root. Aortic annular diameters are measured in the sagittal and coronal planes. Aortic annulus area and perimeter are obtained by direct planimetry in the short-axis view at level of the aortic annulus. (C) MSCT multiplanar reformations of the aortic root. Figure 1 View largeDownload slide Measurements of the aortic root obtained by different methods. (A) 4D auto-aortic valve quantification. 1: automatic assessment of the three orthogonal plane, 2: automatic tracking of LVOT, aortic annulus, and aortic root; 3: automatic trace of the LVOT, aortic annulus, and aortic root borders; 4: tracking’s manual modification; 5: optimized tracking. (B) 3D-TOE manual multiplanar reformations of the aortic root. Aortic annular diameters are measured in the sagittal and coronal planes. Aortic annulus area and perimeter are obtained by direct planimetry in the short-axis view at level of the aortic annulus. (C) MSCT multiplanar reformations of the aortic root. lines (yellow/white) are centred in the middle of the cross section view; lines (yellow/white) are centred and oriented in parallel to the walls of the aorta, in the long-axis views; the green line is grabbed and adjusted to the position where final measurements should be performed on. Then the LVOT segmentation process is started: the system automatically tracks the contours of the LVOT, AA, and part of the aorta. The tracking of the edges is checked and manually adjusted if necessary. After the check of the tracking is done, the software is ready to elaborate the results. The available parameters are: AA diameter, diameter derived from circumference; AA maximum Diameter, longest axis of ellipse fitted to the AV annulus; AA minimum Diameter, shortest axis of ellipse fitted to AV annulus; AA circumference; AA area. 3D manual aortic annulus measurements and calculations Offline cropping of the 3D aortic root data sets was performed using three multiplanar reformations planes using flexi-slices reconstruction tool in mid-systole (Figure 1B). Transverse, sagittal, and coronal planes are oriented. All planes intersect at the centre of the opened valve. Sagittal and coronal planes are aligned in parallel to the long axis of the ascending aorta. The orthogonal planes are rotated to identify the hinge points of the aortic valve leaflets, then the transverse plane is repositioned to the level of the hinge points. The orthogonal planes are repeatedly rotated (‘turn around’ rule) to ensure that the hinge points of the aortic valve leaflets are transected by the transverse plane to obtain the annulus short-axis view. Once the plane is defined, the following annular measurements are obtained: area, perimeter, orthogonal maximum/coronal, and minimum/sagittal diameter. MSCT examination All MSCT examinations were performed using a 64-slice CT system (LightSpeed VCT XTE scanner, GE Healthcare). Retrospectively gated scanning of the thorax and the abdomen were performed; electrocardiogram (ECG) dose modulation was used. A non-ionic, iso-osmolar contrast agent with an iodine concentration of 320 mg/mL (Iodixanol, Visipaque 320, GE Healthcare) was used. All enhanced MSCT acquisitions were performed using our dedicated multiphasic injection protocol12: the total amount of contrast medium was tailored to the patient’s body mass index (from 40 mL to 100 mL at an average infusion rate from 3.2 mL/s to 4.5 mL/s); bolus tracking was performed and image acquisition was started when a pre-defined threshold of 350 HU was achieved in the right ventricle. The data set of the contrast-enhanced scan of the heart was reconstructed at 0.6 mm slices with iterative reconstruction for evaluation at 5% intervals within the 0–95% RR range. All images were transferred to an external workstation (AW 4.5, GE Healthcare) for post-processing analysis. For the evaluation of the aortic root, a dedicated post-processing software (CardIQ X-Press, GE Healthcare) was used. Minimum and maximum diameters, perimeter, and area of the annulus were taken in an orthogonal plane at the level of the basal attachments of all three aortic valve cusps using the reconstructed double oblique transverse view (Figure 1C). Hypothetical prosthesis sizing with MSCT as the gold standard We submitted 3D manual and semi-automated AA measurements (diameters, perimeter, and area) to a single TAVI operator for blinded definition of prosthesis sizing according to echocardiographic measurements to test the agreement between the methods. The final valve sizing was based on MSCT measurement: the oversizing was defined according to manufacturers’ recommendations of each one of the prosthesis used in our cath lab. Statistics The data are presented as mean ± standard deviation (SD) or percentage when appropriate. Comparison between both techniques was performed using a paired Student’s t-test. Pearson’s correlation analysis was used to test correlation between variables. Concordance between the techniques was evaluated using Bland–Altman analysis. To determine the intraobserver and interobserver variability, all measurements were repeated by the same observer in two sessions and by a second blinded independent observer in all 175 patients. The repeatability and reproducibility were assessed using the same data sets, by intraclass correlation coefficient (ICCs) and concordance using the Bland–Altman analysis. An excellent agreement was defined as ICC 0.80. Statistical significance was considered for a two-tailed P-value ≤0.05. The analyses were performed using SPSS version 20.0 (SPSS, Inc., Chicago, IL, USA) and GraphPad Prism version 6.00 (GraphPad Software, La Jolla, CA, USA, www.graphpad.com). Results Study population and TAVI procedure The clinical and procedural characteristics of the study population are summarized in Table 1. Table 1 Baseline clinical and echocardiographic characteristics (n = 175) Age (years) 81.3 ± 6.3 Male (%) 77 (44%) Body mass index (kg/m2) 25.2 ± 4.8 STS score 5.5 ± 4.3 STS MM 25 ± 11.4 Euroscore II 9.3 ± 2.9 Logistic euroscore 16.7 ± 11.3 Atrial fibrillation (%) 30.9% Aortic maximal velocity (m/s) 4.31 ± 0.67 Transaortic mean gradient (mmHg) 48.4 ± 13.9 AVA (cm2) 0.77 ± 0.3 AVAi (cm2/m2) 0.44 ± 0.2 EDVi (mL/m2) 64 ± 23.2 ESVi (mL/m2) 29.2 ± 17.6 Ejection fraction (%) 56.4 ± 11.3 Aortic regurgitation (%) 82.4% Mitral regurgitation (%) 95.9% Age (years) 81.3 ± 6.3 Male (%) 77 (44%) Body mass index (kg/m2) 25.2 ± 4.8 STS score 5.5 ± 4.3 STS MM 25 ± 11.4 Euroscore II 9.3 ± 2.9 Logistic euroscore 16.7 ± 11.3 Atrial fibrillation (%) 30.9% Aortic maximal velocity (m/s) 4.31 ± 0.67 Transaortic mean gradient (mmHg) 48.4 ± 13.9 AVA (cm2) 0.77 ± 0.3 AVAi (cm2/m2) 0.44 ± 0.2 EDVi (mL/m2) 64 ± 23.2 ESVi (mL/m2) 29.2 ± 17.6 Ejection fraction (%) 56.4 ± 11.3 Aortic regurgitation (%) 82.4% Mitral regurgitation (%) 95.9% STS, Society of Thoracic Surgeons; MM, morbidity&mortality; AVA, aortic valve area; EDV, end-diastolic volume; ESV, end-systolic volume. Table 1 Baseline clinical and echocardiographic characteristics (n = 175) Age (years) 81.3 ± 6.3 Male (%) 77 (44%) Body mass index (kg/m2) 25.2 ± 4.8 STS score 5.5 ± 4.3 STS MM 25 ± 11.4 Euroscore II 9.3 ± 2.9 Logistic euroscore 16.7 ± 11.3 Atrial fibrillation (%) 30.9% Aortic maximal velocity (m/s) 4.31 ± 0.67 Transaortic mean gradient (mmHg) 48.4 ± 13.9 AVA (cm2) 0.77 ± 0.3 AVAi (cm2/m2) 0.44 ± 0.2 EDVi (mL/m2) 64 ± 23.2 ESVi (mL/m2) 29.2 ± 17.6 Ejection fraction (%) 56.4 ± 11.3 Aortic regurgitation (%) 82.4% Mitral regurgitation (%) 95.9% Age (years) 81.3 ± 6.3 Male (%) 77 (44%) Body mass index (kg/m2) 25.2 ± 4.8 STS score 5.5 ± 4.3 STS MM 25 ± 11.4 Euroscore II 9.3 ± 2.9 Logistic euroscore 16.7 ± 11.3 Atrial fibrillation (%) 30.9% Aortic maximal velocity (m/s) 4.31 ± 0.67 Transaortic mean gradient (mmHg) 48.4 ± 13.9 AVA (cm2) 0.77 ± 0.3 AVAi (cm2/m2) 0.44 ± 0.2 EDVi (mL/m2) 64 ± 23.2 ESVi (mL/m2) 29.2 ± 17.6 Ejection fraction (%) 56.4 ± 11.3 Aortic regurgitation (%) 82.4% Mitral regurgitation (%) 95.9% STS, Society of Thoracic Surgeons; MM, morbidity&mortality; AVA, aortic valve area; EDV, end-diastolic volume; ESV, end-systolic volume. Among the 175 consecutive patients screened for TAVI in our centre, 26 did not undergo TAVI procedure for different reasons. Comparison of 3D manual, semi-automated, and MSCT measurements in overall population Excellent correlation between semi-automated and manual measurements was observed (Figure 2). There was no significative difference between the two methods for the minor diameter and area, whereas the semi-automated one measured bigger major diameters and smaller perimeters as compared to manual measurements (Table 2, Figure 3). Good agreement between semi-automated and manual measurements was found (Table 3, Figure 3). On average, 3D-TOE semi-automated software underestimated minor diameter, area, and perimeter as compared to manual measurements by 0.004%, 0.006%, and 0.03% respectively, whereas major diameter was overestimated by 0.05%. Table 2 Aortic annular measurements derived from different methods and imaging techniques 3D-TOE manual analysis 3D-TOE semi- automated software MSCT Overall population (n = 172)  Minor diameter (mm) 21.66 ± 2.4 21.58 ± 2.4 21.51 ± 2.6  Major diameter (mm) 23.91 ± 2.7*† 24.88 ± 2.81* 26.86 ± 2.8  Area (mm2) 428.4 ± 90.6* 426 ± 97.6* 444.1 ± 96.5  Perimeter (mm) 75.3 ± 7.8*† 73.3 ± 8.1* 76.6 ± 7.8 Subgroup: without calcific LVOT (n = 51)  Minor diameter(mm) 22.3 ± 2.38‡ 21.9 ± 2.66 21.7 ± 2.5  Major diameter (mm) 24.5 ± 2.9*‡ 25.2 ± 2.8* 27.3 ± 2.9  Area (mm2) 447.8 ± 98.6* 444 ± 97.7* 461.2 ± 99  Perimeter (mm) 76.9 ± 8.9*† 74.3 ± 8.4* 77.6 ± 8.6 Subgroup: calcific LVOT (n = 121)  Minor diameter (mm) 21.42 ± 2.44 21.46 ± 2.3 21.46 ± 2.6  Major diameter (mm) 23.7 ± 2.4*† 24.7 ± 2.8* 26.7 ± 2.8  Area (mm2) 421.4 ± 81.1* 417.5 ± 92.8* 437.9 ± 89.6  Perimeter (mm) 74.7 ± 7.2*† 72.9 ± 7.7* 76.2 ± 7.7 3D-TOE manual analysis 3D-TOE semi- automated software MSCT Overall population (n = 172)  Minor diameter (mm) 21.66 ± 2.4 21.58 ± 2.4 21.51 ± 2.6  Major diameter (mm) 23.91 ± 2.7*† 24.88 ± 2.81* 26.86 ± 2.8  Area (mm2) 428.4 ± 90.6* 426 ± 97.6* 444.1 ± 96.5  Perimeter (mm) 75.3 ± 7.8*† 73.3 ± 8.1* 76.6 ± 7.8 Subgroup: without calcific LVOT (n = 51)  Minor diameter(mm) 22.3 ± 2.38‡ 21.9 ± 2.66 21.7 ± 2.5  Major diameter (mm) 24.5 ± 2.9*‡ 25.2 ± 2.8* 27.3 ± 2.9  Area (mm2) 447.8 ± 98.6* 444 ± 97.7* 461.2 ± 99  Perimeter (mm) 76.9 ± 8.9*† 74.3 ± 8.4* 77.6 ± 8.6 Subgroup: calcific LVOT (n = 121)  Minor diameter (mm) 21.42 ± 2.44 21.46 ± 2.3 21.46 ± 2.6  Major diameter (mm) 23.7 ± 2.4*† 24.7 ± 2.8* 26.7 ± 2.8  Area (mm2) 421.4 ± 81.1* 417.5 ± 92.8* 437.9 ± 89.6  Perimeter (mm) 74.7 ± 7.2*† 72.9 ± 7.7* 76.2 ± 7.7 * P < 0.0001 vs. MSCT. † P < 0.0001 vs. 3D-TOE automated software analysis. ‡ P < 0.02 vs. 3D-TOE automated software analysis. Table 2 Aortic annular measurements derived from different methods and imaging techniques 3D-TOE manual analysis 3D-TOE semi- automated software MSCT Overall population (n = 172)  Minor diameter (mm) 21.66 ± 2.4 21.58 ± 2.4 21.51 ± 2.6  Major diameter (mm) 23.91 ± 2.7*† 24.88 ± 2.81* 26.86 ± 2.8  Area (mm2) 428.4 ± 90.6* 426 ± 97.6* 444.1 ± 96.5  Perimeter (mm) 75.3 ± 7.8*† 73.3 ± 8.1* 76.6 ± 7.8 Subgroup: without calcific LVOT (n = 51)  Minor diameter(mm) 22.3 ± 2.38‡ 21.9 ± 2.66 21.7 ± 2.5  Major diameter (mm) 24.5 ± 2.9*‡ 25.2 ± 2.8* 27.3 ± 2.9  Area (mm2) 447.8 ± 98.6* 444 ± 97.7* 461.2 ± 99  Perimeter (mm) 76.9 ± 8.9*† 74.3 ± 8.4* 77.6 ± 8.6 Subgroup: calcific LVOT (n = 121)  Minor diameter (mm) 21.42 ± 2.44 21.46 ± 2.3 21.46 ± 2.6  Major diameter (mm) 23.7 ± 2.4*† 24.7 ± 2.8* 26.7 ± 2.8  Area (mm2) 421.4 ± 81.1* 417.5 ± 92.8* 437.9 ± 89.6  Perimeter (mm) 74.7 ± 7.2*† 72.9 ± 7.7* 76.2 ± 7.7 3D-TOE manual analysis 3D-TOE semi- automated software MSCT Overall population (n = 172)  Minor diameter (mm) 21.66 ± 2.4 21.58 ± 2.4 21.51 ± 2.6  Major diameter (mm) 23.91 ± 2.7*† 24.88 ± 2.81* 26.86 ± 2.8  Area (mm2) 428.4 ± 90.6* 426 ± 97.6* 444.1 ± 96.5  Perimeter (mm) 75.3 ± 7.8*† 73.3 ± 8.1* 76.6 ± 7.8 Subgroup: without calcific LVOT (n = 51)  Minor diameter(mm) 22.3 ± 2.38‡ 21.9 ± 2.66 21.7 ± 2.5  Major diameter (mm) 24.5 ± 2.9*‡ 25.2 ± 2.8* 27.3 ± 2.9  Area (mm2) 447.8 ± 98.6* 444 ± 97.7* 461.2 ± 99  Perimeter (mm) 76.9 ± 8.9*† 74.3 ± 8.4* 77.6 ± 8.6 Subgroup: calcific LVOT (n = 121)  Minor diameter (mm) 21.42 ± 2.44 21.46 ± 2.3 21.46 ± 2.6  Major diameter (mm) 23.7 ± 2.4*† 24.7 ± 2.8* 26.7 ± 2.8  Area (mm2) 421.4 ± 81.1* 417.5 ± 92.8* 437.9 ± 89.6  Perimeter (mm) 74.7 ± 7.2*† 72.9 ± 7.7* 76.2 ± 7.7 * P < 0.0001 vs. MSCT. † P < 0.0001 vs. 3D-TOE automated software analysis. ‡ P < 0.02 vs. 3D-TOE automated software analysis. Table 3 Average bias and 95% limits of agreement for semi-automated and manual vs. MSCT aortic annulus measurements obtained by the Bland–Altman analysis Overall population (n = 172) Subgroup without LVOT calcification (n = 51) Subgroup with LVOT calcification (n = 121) Average bias (95% CI) Average bias (95% CI) Average bias (95% CI) Software Manual Manual vs. software Software Manual Manual vs. software Software Manual Manual vs. software Minor diameter (mm) 0.07 (−0.2 to 0.4) 0.15 (−0.2 to 0.4) 0.08 (−0.1 to 0.8) 0.2 (−0.2 to 0.8) 0.6 (0.2 to 1) 0.4 (0.1 to 0.7) 0 (0.34 to −0.38) −0.04 (−0.4 to 0.2) −0.04 (−0.3 to 0.19) Major diameter (mm) −1.98 (−2.3 to −1.6) −2.9 (−3.2 to −2.6) −0.9 (−1.7 to −0.2) −2.1 (2.6 to −1.4) −2.8 (−3.3 to −2.0) −0.7 (−1.2 to −0.2) −2 (−2.3 to −1.5) −2.98 (−3.3 to −2.6) −1 (−1.4 to −0.7) Area (mm2) −18.08 (−26.5 to −9.6) −15.7 (−24.4 to −7) 2.4 (−4.7 to 9.4) −17.2 (−27 to −7.46) −13.4 (−32 to −5) 3.8 (−5 to 9.1) −20.4 (−37.1 to −3.3) −16.5 (−26 to −6.3) 3.9 (−7.9 to 9) Perimeter (mm) −3.3 (−4.0 to −2.5) − 1.3 (−2.1 to −0.5) 2 (1.5 to 2.7) −3.3 (−4.8 to −1.8) −0.7 (−2.1 to −0.8) 2.6 (1.8 to 3.9) −3.3 (−4.2 to −2.4) −1.5 (−2.5 to −0.5) 1.8 (1.1 to 2.6) Overall population (n = 172) Subgroup without LVOT calcification (n = 51) Subgroup with LVOT calcification (n = 121) Average bias (95% CI) Average bias (95% CI) Average bias (95% CI) Software Manual Manual vs. software Software Manual Manual vs. software Software Manual Manual vs. software Minor diameter (mm) 0.07 (−0.2 to 0.4) 0.15 (−0.2 to 0.4) 0.08 (−0.1 to 0.8) 0.2 (−0.2 to 0.8) 0.6 (0.2 to 1) 0.4 (0.1 to 0.7) 0 (0.34 to −0.38) −0.04 (−0.4 to 0.2) −0.04 (−0.3 to 0.19) Major diameter (mm) −1.98 (−2.3 to −1.6) −2.9 (−3.2 to −2.6) −0.9 (−1.7 to −0.2) −2.1 (2.6 to −1.4) −2.8 (−3.3 to −2.0) −0.7 (−1.2 to −0.2) −2 (−2.3 to −1.5) −2.98 (−3.3 to −2.6) −1 (−1.4 to −0.7) Area (mm2) −18.08 (−26.5 to −9.6) −15.7 (−24.4 to −7) 2.4 (−4.7 to 9.4) −17.2 (−27 to −7.46) −13.4 (−32 to −5) 3.8 (−5 to 9.1) −20.4 (−37.1 to −3.3) −16.5 (−26 to −6.3) 3.9 (−7.9 to 9) Perimeter (mm) −3.3 (−4.0 to −2.5) − 1.3 (−2.1 to −0.5) 2 (1.5 to 2.7) −3.3 (−4.8 to −1.8) −0.7 (−2.1 to −0.8) 2.6 (1.8 to 3.9) −3.3 (−4.2 to −2.4) −1.5 (−2.5 to −0.5) 1.8 (1.1 to 2.6) Table 3 Average bias and 95% limits of agreement for semi-automated and manual vs. MSCT aortic annulus measurements obtained by the Bland–Altman analysis Overall population (n = 172) Subgroup without LVOT calcification (n = 51) Subgroup with LVOT calcification (n = 121) Average bias (95% CI) Average bias (95% CI) Average bias (95% CI) Software Manual Manual vs. software Software Manual Manual vs. software Software Manual Manual vs. software Minor diameter (mm) 0.07 (−0.2 to 0.4) 0.15 (−0.2 to 0.4) 0.08 (−0.1 to 0.8) 0.2 (−0.2 to 0.8) 0.6 (0.2 to 1) 0.4 (0.1 to 0.7) 0 (0.34 to −0.38) −0.04 (−0.4 to 0.2) −0.04 (−0.3 to 0.19) Major diameter (mm) −1.98 (−2.3 to −1.6) −2.9 (−3.2 to −2.6) −0.9 (−1.7 to −0.2) −2.1 (2.6 to −1.4) −2.8 (−3.3 to −2.0) −0.7 (−1.2 to −0.2) −2 (−2.3 to −1.5) −2.98 (−3.3 to −2.6) −1 (−1.4 to −0.7) Area (mm2) −18.08 (−26.5 to −9.6) −15.7 (−24.4 to −7) 2.4 (−4.7 to 9.4) −17.2 (−27 to −7.46) −13.4 (−32 to −5) 3.8 (−5 to 9.1) −20.4 (−37.1 to −3.3) −16.5 (−26 to −6.3) 3.9 (−7.9 to 9) Perimeter (mm) −3.3 (−4.0 to −2.5) − 1.3 (−2.1 to −0.5) 2 (1.5 to 2.7) −3.3 (−4.8 to −1.8) −0.7 (−2.1 to −0.8) 2.6 (1.8 to 3.9) −3.3 (−4.2 to −2.4) −1.5 (−2.5 to −0.5) 1.8 (1.1 to 2.6) Overall population (n = 172) Subgroup without LVOT calcification (n = 51) Subgroup with LVOT calcification (n = 121) Average bias (95% CI) Average bias (95% CI) Average bias (95% CI) Software Manual Manual vs. software Software Manual Manual vs. software Software Manual Manual vs. software Minor diameter (mm) 0.07 (−0.2 to 0.4) 0.15 (−0.2 to 0.4) 0.08 (−0.1 to 0.8) 0.2 (−0.2 to 0.8) 0.6 (0.2 to 1) 0.4 (0.1 to 0.7) 0 (0.34 to −0.38) −0.04 (−0.4 to 0.2) −0.04 (−0.3 to 0.19) Major diameter (mm) −1.98 (−2.3 to −1.6) −2.9 (−3.2 to −2.6) −0.9 (−1.7 to −0.2) −2.1 (2.6 to −1.4) −2.8 (−3.3 to −2.0) −0.7 (−1.2 to −0.2) −2 (−2.3 to −1.5) −2.98 (−3.3 to −2.6) −1 (−1.4 to −0.7) Area (mm2) −18.08 (−26.5 to −9.6) −15.7 (−24.4 to −7) 2.4 (−4.7 to 9.4) −17.2 (−27 to −7.46) −13.4 (−32 to −5) 3.8 (−5 to 9.1) −20.4 (−37.1 to −3.3) −16.5 (−26 to −6.3) 3.9 (−7.9 to 9) Perimeter (mm) −3.3 (−4.0 to −2.5) − 1.3 (−2.1 to −0.5) 2 (1.5 to 2.7) −3.3 (−4.8 to −1.8) −0.7 (−2.1 to −0.8) 2.6 (1.8 to 3.9) −3.3 (−4.2 to −2.4) −1.5 (−2.5 to −0.5) 1.8 (1.1 to 2.6) Figure 2 View largeDownload slide Correlations between manual and semi-automated software in overall population and in the two subgroups with and without LVOT calcification. Figure 2 View largeDownload slide Correlations between manual and semi-automated software in overall population and in the two subgroups with and without LVOT calcification. Figure 3 View largeDownload slide The Bland–Altman plots for AA measurements by manual and semi-automated software in overall population and in the subgroups with and without LVOT calcification. Figure 3 View largeDownload slide The Bland–Altman plots for AA measurements by manual and semi-automated software in overall population and in the subgroups with and without LVOT calcification. Good correlation between both semi-automated and manual measurements vs. MSCT was observed (Figure 4). Except for the minor diameter (sagittal diameter), the semi-automated and manual measurements significantly underestimated the major diameter (coronal diameter), area, and the perimeter (Table 2). Figure 4 View largeDownload slide Correlations between 3D-TOE and MSCT measurements in overall population. Figure 4 View largeDownload slide Correlations between 3D-TOE and MSCT measurements in overall population. Good agreement between both semi-automated and manual measurements vs. MSCT was found (Table 3, Figure 5). On average, 3D-TOE semi-automated software underestimated major diameter, area, and perimeter compared to MSCT measurements by 7.4%, 3.5%, and 4.4% respectively, whereas minor diameter was overestimated by 0.3% and 3D-TOE manual measurements by 11%, 2.9%, and 1.7%, respectively, whereas minor diameter was overestimated by 0.5%. Figure 5 View largeDownload slide The Bland–Altman plots for minor and major diameters, area, and perimeter by manual, semi-automated, and MSCT measurements in overall population. Figure 5 View largeDownload slide The Bland–Altman plots for minor and major diameters, area, and perimeter by manual, semi-automated, and MSCT measurements in overall population. 3D-TOE-derived semi-automated software major diameter and area showed narrower limits of agreement and smaller bias compared to manual ones, whereas 3D-TOE software-derived perimeter showed only narrower limits of agreement than manual analysis as illustrated by the Bland–Altman Plot (Figure 5). The mean time required for the AA analysis was 50 ± 7 s and 205 ± 39 s by the semi-automated and manual analysis, respectively (P = 0.001), leading to an average time-saving of 155 ± 41 s per analysis. Subgroup analysis Patients without LVOT calcification (n = 51, 28%) Excellent correlation between both semi-automated and manual measurements was found (Figure 2). There was no difference between 3D semi-automated software and manual analysis with regard to area, whereas 3D semi-automated showed slightly smaller AA minor diameter and perimeter and bigger major diameter (Table 2). Good agreement between semi-automated and manual measurements was observed (Table 3, Figure 3). Good correlation between both semi-automated and manual measurements vs. MSCT was found (Figure 6). With the exception of AA minor diameter, 3D semi-automated and manual measurements significantly underestimate the major diameter, AA area, and perimeter (Table 2). Good agreement between both semi-automated and manual measurements vs. MSCT was observed (Table 3). 3D-TOE-derived software major diameter and area had narrower limits of agreement and least bias than manual ones, whereas 3D-TOE-derived software perimeter showed only narrowest limits of agreements than manual one (Table 3). Figure 6 View largeDownload slide Correlations in the subgroup of patients without LVOT calcification. Figure 6 View largeDownload slide Correlations in the subgroup of patients without LVOT calcification. Patients with LVOT calcification (n = 121, 70%) The correlation between the measurements obtained by the automated and manual analysis was good (Figure 2), as well as good agreement between the two methods was found (Table 3, Figure 3). There was no significative difference between the two methods for the minor diameter and area, whereas the semi-automated software has bigger major diameters and smaller perimeters as compared to manual measurements (Table 2, Figure 3). Similarly, the correlation between the measurements obtained by the automated and manual analysis vs. MSCT was good (Figure 7), as well as good agreement between techniques was found (Table 3). Except for the minor diameter, 3D semi-automated and manual measurements significantly underestimated the major diameter, area, and perimeter (Table 2). Finally, 3D-TOE-derived semi-automated major diameter and area had narrower limits of agreement and least bias than manual ones, whereas 3D-TOE-derived software perimeter showed only narrowest limits of agreements than manual ones (Table 3). Figure 7 View largeDownload slide Correlations in subgroup of patients with LVOT calcification. Figure 7 View largeDownload slide Correlations in subgroup of patients with LVOT calcification. Hypothetical prosthesis sizing selection When we tested the agreement between 3D manual and semi-automated methods vs. MSCT regarding the hypothetical prosthesis sizing to be implanted, a moderate agreement for both techniques was found: 96/149 (64%) patients, Kappa agreement 0.5, and 97/149 (65%) patients, Kappa agreement 0.5 for automatic and manual analysis, respectively. The discrepancy between the two imaging modalities in prosthesis sizing selection is more remarkable for the intermediate sizes than for the ends (Figure 8). Figure 8 View largeDownload slide Discrepancy in THV sizing according to 3D-TOE vs. CT measurement, for 3D-TOE software in Panel A and 3D-TOE manual analysis in Panel B. THV, transcatheter heart valve. Figure 8 View largeDownload slide Discrepancy in THV sizing according to 3D-TOE vs. CT measurement, for 3D-TOE software in Panel A and 3D-TOE manual analysis in Panel B. THV, transcatheter heart valve. Interobserver and intraobserver variability Interobserver and intraobserver ICCs and biases were excellent for all measurements for both techniques (manual and semi-automated) (Table 4). Table 4 Inter- and intra-observer variability Variable 3D-TOE manual analysis 3D-TOE semi-automated analysis Intraobserver Interobserver Intraobserver Interobserver Minor diameter (mm) ICC: 0.91* ICC: 0.87* ICC: 0.93* ICC: 0.92* Bias: −0.06 (−0.3 to 0.2) Bias: 0.51 (0.19 to 0.83) Bias: −0.1 (−0.4 to 0.08) Bias: −0.3 (−0.5 to 0.05) Major diameter (mm) ICC: 0.94* ICC: 0.92* ICC: 0.93* ICC: 0.90* Bias: −0.11 (−0.4 to 0.1) Bias: 0.14 (−0.1 to 0.49) Bias: −0.08 (−0.4 to 0.2) Bias: −0.08 (−0.4 to 0.3) Area (mm2) ICC: 0.92* ICC: 0.91* ICC: 0.94* ICC: 0.92* Bias: −6.7 (−17.3 to 3.9) Bias: −9.7 (−17.2 to −2.2) Bias: −5.7 (−14.6 to 3.2) Bias: −7.6 (−15.2 to −0.1) Perimeter (mm) ICC: 0.94* ICC: 0.88* ICC: 0.96* ICC: 0.91* Bias: −0.6 (−1.3 to 0.1) Bias: −0.8 (−1.3 to 0.8) Bias: −0.3 (−0.9 to 0.3) Bias: −0.8 (−1.7 to −0.0) Variable 3D-TOE manual analysis 3D-TOE semi-automated analysis Intraobserver Interobserver Intraobserver Interobserver Minor diameter (mm) ICC: 0.91* ICC: 0.87* ICC: 0.93* ICC: 0.92* Bias: −0.06 (−0.3 to 0.2) Bias: 0.51 (0.19 to 0.83) Bias: −0.1 (−0.4 to 0.08) Bias: −0.3 (−0.5 to 0.05) Major diameter (mm) ICC: 0.94* ICC: 0.92* ICC: 0.93* ICC: 0.90* Bias: −0.11 (−0.4 to 0.1) Bias: 0.14 (−0.1 to 0.49) Bias: −0.08 (−0.4 to 0.2) Bias: −0.08 (−0.4 to 0.3) Area (mm2) ICC: 0.92* ICC: 0.91* ICC: 0.94* ICC: 0.92* Bias: −6.7 (−17.3 to 3.9) Bias: −9.7 (−17.2 to −2.2) Bias: −5.7 (−14.6 to 3.2) Bias: −7.6 (−15.2 to −0.1) Perimeter (mm) ICC: 0.94* ICC: 0.88* ICC: 0.96* ICC: 0.91* Bias: −0.6 (−1.3 to 0.1) Bias: −0.8 (−1.3 to 0.8) Bias: −0.3 (−0.9 to 0.3) Bias: −0.8 (−1.7 to −0.0) Bias was obtained using the Bland–Altman analysis with 95% CI. * P < 0.001. Table 4 Inter- and intra-observer variability Variable 3D-TOE manual analysis 3D-TOE semi-automated analysis Intraobserver Interobserver Intraobserver Interobserver Minor diameter (mm) ICC: 0.91* ICC: 0.87* ICC: 0.93* ICC: 0.92* Bias: −0.06 (−0.3 to 0.2) Bias: 0.51 (0.19 to 0.83) Bias: −0.1 (−0.4 to 0.08) Bias: −0.3 (−0.5 to 0.05) Major diameter (mm) ICC: 0.94* ICC: 0.92* ICC: 0.93* ICC: 0.90* Bias: −0.11 (−0.4 to 0.1) Bias: 0.14 (−0.1 to 0.49) Bias: −0.08 (−0.4 to 0.2) Bias: −0.08 (−0.4 to 0.3) Area (mm2) ICC: 0.92* ICC: 0.91* ICC: 0.94* ICC: 0.92* Bias: −6.7 (−17.3 to 3.9) Bias: −9.7 (−17.2 to −2.2) Bias: −5.7 (−14.6 to 3.2) Bias: −7.6 (−15.2 to −0.1) Perimeter (mm) ICC: 0.94* ICC: 0.88* ICC: 0.96* ICC: 0.91* Bias: −0.6 (−1.3 to 0.1) Bias: −0.8 (−1.3 to 0.8) Bias: −0.3 (−0.9 to 0.3) Bias: −0.8 (−1.7 to −0.0) Variable 3D-TOE manual analysis 3D-TOE semi-automated analysis Intraobserver Interobserver Intraobserver Interobserver Minor diameter (mm) ICC: 0.91* ICC: 0.87* ICC: 0.93* ICC: 0.92* Bias: −0.06 (−0.3 to 0.2) Bias: 0.51 (0.19 to 0.83) Bias: −0.1 (−0.4 to 0.08) Bias: −0.3 (−0.5 to 0.05) Major diameter (mm) ICC: 0.94* ICC: 0.92* ICC: 0.93* ICC: 0.90* Bias: −0.11 (−0.4 to 0.1) Bias: 0.14 (−0.1 to 0.49) Bias: −0.08 (−0.4 to 0.2) Bias: −0.08 (−0.4 to 0.3) Area (mm2) ICC: 0.92* ICC: 0.91* ICC: 0.94* ICC: 0.92* Bias: −6.7 (−17.3 to 3.9) Bias: −9.7 (−17.2 to −2.2) Bias: −5.7 (−14.6 to 3.2) Bias: −7.6 (−15.2 to −0.1) Perimeter (mm) ICC: 0.94* ICC: 0.88* ICC: 0.96* ICC: 0.91* Bias: −0.6 (−1.3 to 0.1) Bias: −0.8 (−1.3 to 0.8) Bias: −0.3 (−0.9 to 0.3) Bias: −0.8 (−1.7 to −0.0) Bias was obtained using the Bland–Altman analysis with 95% CI. * P < 0.001. Discussion The present study demonstrates that: (i) 3D-TOE semi-automated software analysis of AA is: feasible; reliable with a good correlation between 3D-TOE and MSCT measurements; and reproducible with a low intra- and inter-observer variability; (ii) 3D-TOE manual and semi-automated analysis underestimate the major diameter, area, and perimeter compared to respective MSCT measurements; (iii) using MSCT as the ‘gold standard’, 3D-TOE semi-automated measurements showed slightly better correlations, the least underestimation, and narrowest limits of agreements for most of the parameters compared with their respective manual ones; (iv) moderate agreement between manual, semi-automated, and MSCT measurements regarding prosthesis sizing selection was found. Accurate measurements of AA are essential for pre-procedural TAVI planning and non-invasive imaging modalities play an important role in this setting. MSCT cross-sectional area and perimeter are considered the gold standard for AA sizing before TAVI. Numerous studies have shown the advantages of 3D assessment of the annulus compared with 2D assessment using multiple modalities, including MSCT,5,6,13 3D-TOE,14–17 and cardiac MRI.5 Cross-sectional 3D-TOE annulus measurements generally underestimate the MSCT ones.7,9,16 An error in the range of 10% that was found in previous published reports could be clinically significant and potentially dangerous for the patient. The current study shows good correlation between 3D-TOE methods and MSCT, and smaller error range by 3D-TOE manual and semi-automated analysis than observed in previous studies. Novel automated 3D-TOE reconstruction tools have recently been introduced, performing automated reconstruction and analysis of the aortic root starting from data set using a pre-defined algorithm.10 The current study suggests that the measurements obtained with this software are accurate and highly correlative with MSCT ones with excellent interobserver and intraobserver variability. Semi-automated analysis shows slightly better correlations with MSCT measurements, narrower limits of agreement and lesser bias than manual measurements. It is less time-consuming than manual analysis, at least two and a half minutes per analysis time-saving. The software seems to have good performance in both patients without and with LVOT calcifications. Furthermore, the operator can adjust the axes and the automatic tracking. Therefore, the software should be referred as ‘3D-TOE semi-automated’ application and not ‘automated’: that could be the reason why it performed better than manual analysis made by experienced cardiologists. However, Khalique et al.9 by the off-label use of 3D-TOE software obtained excellent correlation between 3D-TOE and MSCT measurements and smaller absolute differences (≤1%) than those obtained in our study. As suggested in the study by Tsang et al.,18 3D-TOE and MSCT clearly have different imaging limitations that may lead to the selection of slightly different transverse planes for annulus assessment. In addition, ectopic calcification may introduce significant measurement errors that differ by techniques. Indeed, in our patients without LVOT calcification, we observed a slight increase of the correlation and the least bias between 3D-TOE and MSCT measurements both with manual and automatic software analyses. The two modalities also differ in temporal resolution, thus measurements may be performed in slightly different points in the cardiac cycle.19 Moreover we know that generally, the annular size (mean diameter) as measured by TOE is smaller when compared MSCT measurement in mid-systole.20 Since we measured in mid-systole for 3D-TOE and in mid-diastole for MSCT, our findings could reflect these overall differences between the two modalities. Finally, 3D-TOE and MSCT have distinct strengths and weaknesses. 3D-TOE has superior temporal resolution, which often allows for differentiation of the basal aortic valve hinge point on the basis of visualized separation of calcium, and essentially eliminates motion-based artefacts. However, 3D-TOE is limited by suboptimal lateral resolution in the coronal plane, which reduces the ability to measure the blood/tissue interface in this plane, particularly in case of ectopic calcification (the coronal diameter, indeed, shows the least underestimation and the worst correlations) (Figure 9). On the contrary, MSCT typically provides superior tissue/lumen contrast but may be limited by artefacts because of partial volume-averaging effects (blooming), heart/lung motion, patient motion, and arrhythmias. Figure 9 View largeDownload slide Determination of annulus size by 3D-TOE in patients without (Panels A and B) and with LVOT calcification (Panels B and C, white arrows). 3D reconstructions are affected by suboptimal lateral resolution in the coronal plane (red arrows), which reduces the ability to measure the blood/tissue interface in this plane, particularly in case of ectopic calcification (Panel C). Figure 9 View largeDownload slide Determination of annulus size by 3D-TOE in patients without (Panels A and B) and with LVOT calcification (Panels B and C, white arrows). 3D reconstructions are affected by suboptimal lateral resolution in the coronal plane (red arrows), which reduces the ability to measure the blood/tissue interface in this plane, particularly in case of ectopic calcification (Panel C). We assessed the clinical implications of 3D-TOE AA measurements on the prosthesis sizing selection. We found a moderate agreement between manual and automatic measurements vs. manufacturer-recommended CT-based sizing algorithm. Among the 35% of discordance, 3D-TOE measurements lead to prosthesis underestimation in most of the cases. These findings could be explained by several factors affecting prosthesis sizing selection. Indeed, the degree of calcification and an elliptic shape of AA establish whether to oversize or undersize the prosthesis. Therefore, in case the prosthesis sizing should be selected only on the basis of the 3D-TOE measurements, we might speculate that it is necessary to apply a correction factor of overestimation with respect to the manufacturer-recommended CT-based sizing algorithm. This overestimation may be the same average difference between the measurements observed in our study according to the presence or the absence of LVOT calcification. This software could be used alternatively to MSCT in particular settings such as for contrast nephrotoxicity avoidance, which is especially important if we consider that TAVI candidates are usually elderly people with high risk of renal failure, or in patients with severe allergy to ionidated contrast or in cases of arrhythmias that makes ECG gating difficult for MSCT acquisition. However, MSCT offers a wide range of information for pre-procedural screening including the exact delineation of the access rout which is crucial for transfemoral vs. transapical selection, the evaluation of the distance of the coronary ostia from AA and the exact location and amount of valvular calcifications. Limitations The study is a single-centre observational study, in which pre-procedural MSCT and 3D-TOE were used for AA evaluation, but final prosthesis size was decided only on the basis of CT measurement: 3D-TOE-based prosthesis sizing was performed retrospectively by only one TAVI operator in blinded fashion. The high reproducibility of these measurements is likely dependent on training and experience, and thus our findings cannot necessarily be generalized to less-experienced readers. Finally, both modalities are user dependent, and optimal image acquisition and analysis are always paramount for adequate annular assessment. Given these differences, echocardiography and MSCT have to be considered as complementary imaging modalities. Conclusions Our results support the use of the semi-automated software in clinical practice, which could be an alternative to MSCT for the pre-procedural assessment of AA. 3D-TOE may be a valuable tool for prosthetic sizing in patients where MSCT is not feasible or desirable, such as in the setting of significant renal impairment, or in patients in whom MSCT was not reliable enough for pre-procedural planning, due to poor imaging quality. References 1 Vahanian A , Alfieri O , Andreotti F , Antunes MJ , Baron-Esquivias G , Baumgartner H et al. Guidelines on the management of valvular heart disease (version 2012) The Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European . Eur Heart J 2012 ; 33 : 2451 – 96 . Google Scholar CrossRef Search ADS PubMed 2 Leon MB , Smith CR , Mack MJ , Makkar RR , Svensson LG , Kodali SK et al. Transcatheter or surgical aortic-valve replacement in intermediate-risk patients . N Engl J Med 2016 ; 374 : 1609 – 20 . Google Scholar CrossRef Search ADS PubMed 3 Moss RR , Ivens E , Pasupati S , Humphries K , Thompson CR , Munt B et al. Role of echocardiography in percutaneous aortic valve implantation . JACC Cardiovasc Imaging 2008 ; 1 : 15 – 24 . Google Scholar CrossRef Search ADS PubMed 4 Leipsic J , Gurvitch R , Labounty TM , Min JK , Wood D , Johnson M et al. Multidetector computed tomography in transcatheter aortic valve implantation . JACC Cardiovasc Imaging 2011 ; 4 : 416 – 29 . Google Scholar CrossRef Search ADS PubMed 5 Koos R , Altiok E , Mahnken AH , Neizel M , Dohmen G , Marx N et al. Evaluation of aortic root for definition of prosthesis size by magnetic resonance imaging and cardiac computed tomography: implications for transcatheter aortic valve implantation . Int J Cardiol 2012 ; 158 : 353 – 8 . Google Scholar CrossRef Search ADS PubMed 6 Altiok E , Koos R , Schröder J , Brehmer K , Hamada S , Becker M et al. Comparison of two-dimensional and three-dimensional imaging techniques for measurement of aortic annulus diameters before transcatheter aortic valve implantation . Heart 2011 ; 97 : 1578 – 84 . Google Scholar CrossRef Search ADS PubMed 7 Schultz CJ , Moelker A , Piazza N , Tzikas A , Otten A , Nuis RJ et al. Three dimensional evaluation of the aortic annulus using multislice computer tomography: are manufacturer’s guidelines for sizing for percutaneous aortic valve replacement helpful? Eur Heart J 2010 ; 31 : 849 – 56 . Google Scholar CrossRef Search ADS PubMed 8 Ng ACT , Delgado V , Van Der Kley F , Shanks M , Van De Veire NRL , Bertini M et al. Comparison of aortic root dimensions and geometries before and after transcatheter aortic valve implantation by 2-and 3-dimensional transesophageal echocardiography and multislice computed tomography . Circ Cardiovasc Imaging 2010 ; 3 : 94 – 102 . Google Scholar CrossRef Search ADS PubMed 9 Khalique OK , Kodali SK , Paradis JM , Nazif TM , Williams MR , Einstein AJ et al. Aortic annular sizing using a novel 3-dimensional echocardiographic method use and comparison with cardiac computed tomography . Circ Cardiovasc Imaging 2014 ; 7 : 155 – 63 . Google Scholar CrossRef Search ADS PubMed 10 García-Martín A , Lázaro-Rivera C , Fernández-Golfín C , Salido-Tahoces L , Moya-Mur J-L , Jiménez-Nacher J-J et al. Accuracy and reproducibility of novel echocardiographic three-dimensional automated software for the assessment of the aortic root in candidates for transcatheter aortic valve replacement . Eur Heart J Cardiovasc Imaging 2016 ; 17 : 772 – 8 . Google Scholar CrossRef Search ADS PubMed 11 Zamorano JL , Badano LP , Bruce C , Chan K-L , Goncalves A , Hahn RT et al. EAE/ASE recommendations for the use of echocardiography in new transcatheter interventions for valvular heart disease . Eur Heart J 2011 ; 32 : 2189 – 214 . Google Scholar CrossRef Search ADS PubMed 12 Spagnolo P , Giglio M , Di Marco D , Latib A , Besana F , Chieffo A et al. Feasibility of ultra-low contrast 64-slice computed tomography angiography before transcatheter aortic valve implantation: a real-world experience . Eur Heart J Cardiovasc Imaging 2016 ; 17 : 24 – 33 . Google Scholar CrossRef Search ADS PubMed 13 Bloomfield GS , Gillam LD , Hahn RT , Kapadia S , Leipsic J , Lerakis S et al. A practical guide to multimodality imaging of transcatheter aortic valve replacement . JACC Cardiovasc Imaging 2012 ; 5 : 441 – 55 . Google Scholar CrossRef Search ADS PubMed 14 Janosi RA , Kahlert P , Plicht B , Wendt D , Eggebrecht H , Erbel R et al. Measurement of the aortic annulus size by real-time three-dimensional transesophageal echocardiography . Minim Invasive Ther Allied Technol 2011 ; 20 : 85 – 94 . Google Scholar CrossRef Search ADS PubMed 15 Santos N , De Agustín JA , Almería C , Gonçalves A , Marcos-Alberca P , Fernández-Golfín C et al. Prosthesis/annulus discongruence assessed by three-dimensional transoesophageal echocardiography: a predictor of significant paravalvular aortic regurgitation after transcatheter aortic valve implantation . Eur Heart J Cardiovasc Imaging 2012 ; 13 : 931 – 7 . Google Scholar CrossRef Search ADS PubMed 16 Jilaihawi H , Doctor N , Kashif M , Chakravarty T , Rafique A , Makar M et al. Aortic annular sizing for transcatheter aortic valve replacement using cross-sectional 3-dimensional transesophageal echocardiography . J Am Coll Cardiol 2013 ; 61 : 908 – 16 . Google Scholar CrossRef Search ADS PubMed 17 Shahgaldi K , da Silva C , Bäck M , Rück A , Manouras A , Sahlén A. Transesophageal echocardiography measurements of aortic annulus diameter using biplane mode in patients undergoing transcatheter aortic valve implantation . Cardiovasc Ultrasound 2013 ; 11 : 5 . Google Scholar CrossRef Search ADS PubMed 18 Tsang W , Bateman MG , Weinert L , Pellegrini G , Mor-Avi V , Sugeng L et al. Accuracy of aortic annular measurements obtained from three-dimensional echocardiography, CT and MRI: human in vitro and in vivo studies . Heart 2012 ; 98 : 1146 – 52 . Google Scholar CrossRef Search ADS PubMed 19 Schultz CJ , Moelker AD , Tzikas A , Rossi A , Van Geuns RJ , De Feyter PJ et al. Cardiac CT: necessary for precise sizing for transcatheter aortic implantation . EuroIntervention 2010 ; 6 (Suppl G): G6 – 13 . Google Scholar CrossRef Search ADS PubMed 20 Husser O , Rauch S , Endemann DH , Resch M , Nunez J , Bodi V et al. Impact of three-dimensional transesophageal echocardiography on prosthesis sizing for transcatheter aortic valve implantation . Catheter Cardiovasc Interv 2012 ; 80 : 956 – 63 . Google Scholar CrossRef Search ADS PubMed Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.

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European Heart Journal – Cardiovascular ImagingOxford University Press

Published: Feb 6, 2018

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