Comparison of aortic annulus size by transesophageal echocardiography and computed tomography angiography with direct surgical measurement

Computed tomography is better than echocardiography in predicting balloon-expandable transcutaneous implantation valve size in a real-world clinical practice single-center study

AIMS

Transcatheter aortic valve replacement (TAVR) has become the standard of care for selected patients with severe aortic stenosis. Multidetector computed tomography (MDCT) and transoesophageal 2D/3D (two-dimensional/three-dimensional) echocardiography (ECHO) are used for aortic annulus (AA) sizing. The aim of this study was to compare the accuracy of AA sizing by ECHO versus MDCT for Edwards Sapien balloon expandable valve in a single center.

METHODS AND RESULTS

Data from 145 consecutive patients with TAVR (Sapien XT or Sapien S3) were analyzed retrospectively. A total of 139 (96%) patients had favorable outcomes after TAVR (at most mild aortic regurgitation and only one valve implanted). The 3D ECHO AA area and area-derived diameter were smaller than the corresponding MDCT parameters (464 ± 99 vs. 479 ± 88 mm2 , p < .001, and 24.2 ± 2.7 vs. 25.0 ± 5.5 mm, p = .002, respectively). The 2D ECHO annulus measurement was smaller than both the MDCT and 3D ECHO area-derived diameters (22.6 ± 2.9 vs. 25.0 ± 5.5 mm, p = .013, and 22.6 ± 2.9 vs. 24.2 ± 2.7 mm, p < .001, respectively) but larger than the minor axis diameter of the AA derived from MDCT and 3D ECHO by multiplanar reconstruction (p < .001). The 3D ECHO circumference-derived diameter was also smaller than the MDCT circumference-derived diameter (24.3 ± 2.5 vs. 25.0 ± 2.3, p = .007). The sphericity index by 3D ECHO was smaller than that by MDCT (1.2 ± .1 vs. 1.3 ± .1, p < .001). In up to 1/3 of the patients, 3D ECHO measurements would have predicted different (generally smaller) valve size than was the valve size implanted with favorable result. The concordance of the implanted valve size with the recommended size based on preprocedural MDCT and 3D ECHO AA area was 79.4% versus 61% (p = .001), and for the area-derived diameter, the concordance was 80.1% versus 61.7% (p = .001). 2D ECHO diameter concordance was similar to MDCT (78.7%).

CONCLUSIONS

3D ECHO AA measurements are smaller than MDCT measurements. If 3D ECHO-based parameters alone are used to size the Edwards Sapien balloon expandable valve, then the selected valve size would have been smaller than the valve size implanted with favorable result in 1/3 of the patients. MDCT preprocedural TAVR assessment should be the preferred method over 3D ECHO in routine clinical practice to determine Edwards Sapien valve size.

Canine mitral valve size as measured by computed tomography

OBJECTIVE

To measure the mitral annulus in dogs. Our hypothesis was that mitral measurement would be possible and consistent among observers using CT.

SAMPLE

Thoracic CT scans of dogs without known heart disease.

PROCEDURES

Five trained investigators measured 4 aspects of the mitral valve and the fourth thoracic vertebrae (T4) length using multiplanar reformatting tools. Ten randomly chosen animals were measured by all investigators to determine interobserver reliability.

RESULTS

There were 233 CT scans eligible for inclusion. Dogs weighed 2 to 96 kg (mean, 28.1 kg), with a variety of breeds represented. Golden Retrievers (n = 28) and Labrador Retrievers (n = 37) were overrepresented. The intraclass correlations were all greater than 0.9, showing excellent agreement between observers. The means and SDs of each measurement were as follows: trigone-to-trigone distance, 17.2 ± 4.7 mm; the remaining circumference, 79.0 ± 17.5 mm; commissure-to-commissure distance, 30.8 ± 6.5 mm; septal leaflet-to-lateral leaflet distance, 26.3 ± 6.0 mm; T4 length, 16.9 ± 3.1 mm; and the total circumference normalized by T4, 5.7 ± 0.7 mm.

CLINICAL RELEVANCE

This study provides information that may help in the development of future treatment for mitral valve dysfunction and subsequent annular enlargement.

Aortic annulus sizing in bicuspid and tricuspid aortic valves using CT in patients with surgical aortic valve replacement

The purpose of this study was to evaluate whether bicuspid anatomy affects the discrepancy between CT-derived annular size and intraoperative size. We retrospectively analyzed annular measurements in 667 patients who underwent surgical aortic valve replacement (AVR). Preoperative CT measurements of the aortic annulus were compared to surgically implanted valve sizes. To evaluate whether the bicuspid valve affects the differences between CT annulus diameter and surgical AVR size, patients with diameter larger by > 10% (CT-Lg group) on CT, compared to surgical AVR size, were compared with those having size difference < 10% (CT-Sim group). Propensity score matching yielded 183 matched patients from each group. Bicuspid aortic valve annulus parameters significantly correlated with surgical aortic valve size (r = 0.52-0.71; for all, p < 0.01). The most representative measurements corresponded to surgical aortic valve size were area-derived diameters in tricuspid aortic valve (r = 0.69, p < 0.001) and bicuspid without raphe (r = 0.71, p < 0.001), and perimeter-derived diameter in bicuspid with raphe (r = 0.63, p < 0.001). After propensity score matching, native valve type was not different between CT-Sim and CT-Lg groups. In multivariable analysis, the difference between CT-derived diameter and surgical AVR size was affected by the operator factor and types of prosthesis. Bicuspid aortic annulus diameters measured on CT showed a significant correlation with surgical aortic valve size. The difference between CT-derived diameter and surgical AVR size is affected by operator factor and the types of prosthesis but not affected by the bicuspid valve.

Estimating the Haemodynamic Streamline Vena Contracta as the Effective Orifice Area Measured from Reconstructed Multislice Phase-contrast MR Images for Patients with Moderately Accelerated Aortic Stenosis

PURPOSE

In aortic stenosis (AS), the discrepancy between moderately accelerated flow and effective orifice area (EOA) continues to pose a challenge. We developed a method of measuring the vena contracta area as hemodynamic EOA using cardiac MRI focusing on AS patients with a moderately accelerated flow to solve the problem that AS severity can currently be determined only by echocardiography.

METHODS

We investigated 40 patients with a peak transvalvular velocity > 3.0 m/s on transthoracic echocardiography (TTE). The patients were divided into highly accelerated and moderately accelerated AS groups according to whether or not the peak transvalvular velocity was ≥ 4.0 m/s. From the multislice 2D cine phase-contrast MRI data, the cross-sectional area of the vena contracta of the reconstructed streamline in the Valsalva sinus was defined as MRI-EOAs. Patient symptoms and echocardiography data, including EOA (defined as TTE-EOA), were derived from the continuity equation using TTE.

RESULTS

All participants in the highly accelerated AS group (n = 19) showed a peak velocity ≥ 4.0 m/s in MRI. Eleven patients in the moderately accelerated AS group (n = 21) had a TTE-EOA < 1.00 cm². In the moderately accelerated AS group, MRI-EOAs demonstrated a strong correlation with TTE-EOAs (r = 0.76, P < 0.01). Meanwhile, in the highly accelerated AS group, MRI-EOAs demonstrated positivity but a moderate correlation with TTE-EOAs (r = 0.63, P = 0.004). MRI-EOAs were overestimated compared to TTE-EOAs. In terms of the moderately accelerated AS group, the best cut-off value for MRI-EOAs was < 1.23 cm², compatible with TTE-EOAs < 1.00 cm², with an excellent prediction of the New York Heart Association classification ≥ III (sensitivity 87.5%, specificity 76.9%).

CONCLUSION

MRI-EOAs may be an alternative to conventional echocardiography for patients with moderately accelerated AS, especially those with discordant echocardiographic parameters.

Multimodality imaging assessment of bicuspid aortic valve disease, thoracic aortic ectasia, and thoracic aortic aneurysmal disease

Acute aortic syndromes have extremely high mortality rates and those with aortic dilation are at increased risk for these often catastrophic events. Serial monitoring of patients with aortic dilation is critical to determine the appropriate timing of preventative interventions. The thoracic aorta can be imaged and measured using multiple imaging modalities including transthoracic echocardiography, transesophageal echocardiography, multidetector cardiac computed tomography, and magnetic resonance imaging. There has not been agreement on the specific techniques that should be used to measure thoracic aortic dimensions with each imaging modality, leading to potential errors and challenges in comparing changes in measurements over time. It is critical to understand the current recommendations on thoracic aortic measurements for each imaging modality and cardiovascular imaging specialists need to be explicit about the methods that they have used to derive the thoracic aortic measurements. In those at high risk for aortic pathology, such as those with connective tissue diseases or bicuspid aortic valve, a multimodality imaging strategy incorporating echocardiography including three-dimensional measurements along with cardiac computed tomography or magnetic resonance imaging should be used to establish aortic dimensions and for continued monitoring to avoid progression to acute aortic syndromes.

Multi-parametric approach to predict prosthetic valve size using CMR and clinical data: insights from SAVR

The purpose of this investigation was to characterize the CMR and clinical parameters that correlate to prosthetic valve size (PVS) determined at SAVR and develop a multi-parametric model to predict PVS. Sixty-two subjects were included. Linear/area measurements of the aortic annulus were performed on cine CMR images in systole/diastole on long/short axis (SAX) views. Clinical parameters (age, habitus, valve lesion, valve morphology) were recorded. PVS determined intraoperatively was the reference value. Data were analyzed using Spearman correlation. A prediction model combining imaging and clinical parameters was generated. Imaging parameters had moderate to moderately strong correlation to PVS with the highest correlations from systolic SAX mean diameter (r = 0.73, p < 0.0001) and diastolic SAX area (r = 0.73, p < 0.0001). Age was negatively correlated to PVS (r = - 0.47, p = 0.0001). Weight was weakly correlated to PVS (r = 0.27, p = 0.032). AI and bicuspid valve were not predictors of PVS. A model combining clinical and imaging parameters had high accuracy in predicting PVS (R² = 0.61). Model predicted mean PVS was 23.3 mm (SD 1.1); actual mean PVS was 23.3 mm (SD 1.3). The Spearman r of the model (0.80, 95% CI 0.683-0.874) was significantly higher than systolic SAX area (0.68, 95% CI 0.516-0.795). Clinical parameters like age and habitus impact PVS; valve lesion/morphology do not. A multi-parametric model demonstrated high accuracy in predicting PVS and was superior to a single imaging parameter. A multi-parametric approach to device sizing may have future application in TAVR.

Efficacy of preoperative electrocardiographic-gated computed tomography in predicting the accurate aortic annulus diameter in surgical aortic valve replacement

OBJECTIVE

Electrocardiographic (ECG)-gated computed tomography (CT) can be used to determine which valve and size should be used in transcatheter aortic valve replacement (TAVR). It is beneficial to predict the accurate annulus diameter in surgical aortic valve replacement (SAVR), which can help in determining the surgical strategy. We aimed to compare the predicted aortic annulus size with the actual annulus size measured intraoperatively and to examine its validity.

METHODS

A total of 88 patients underwent isolated or concomitant SAVR in 2018 at our hospital. The study population consisted of 45 patients who underwent preoperative CT assessment and intraoperative measurement. The perimeter- and area-derived diameters at the level of basal attachments were determined using CT, and the lower value among the two was defined as the predicted aortic annulus (CTpredict). The predicted aortic annulus (TTEpredict) was measured by transthoracic echography in the parasternal long-axis view. An actual-sized ball sizer was inserted into the annulus intraoperatively. True annulus size was determined as the labeled size that just fits on the annulus, and labeled size plus 1 mm was determined as one that passes through the annulus.

RESULTS

There was better agreement with minimal bias between CTpredict and true annulus size as demonstrated in the Bland-Altman analysis with an intraclass correlation coefficient of 0.796 compared with TTEpredict.

CONCLUSION

ECG-gated CT is also helpful in predicting the annulus diameter even in patients undergoing SAVR. This has important clinical implications for planning SAVR, including the surgical approach.

Three-dimensional printing for assessment of paravalvular leak in transcatheter aortic valve implantation

Background

Three-dimensional (3D) models have the unique ability to replicate individualized cardiac anatomy and may therefore provide clinical benefit. Transcatheter aortic valve implantation (TAVI) currently relies on preoperative imaging for accurate valve sizing, type of valve used, and avoidance of complications. Three-dimensional (3D) modelling may provide benefit for optimal preoperative TAVI planning. The goal of this study is to assess the utility of 3D modelling in the prediction of paravalvular leak (PVL) post TAVI.

Methods

Retrospective analysis of five patients who underwent TAVI at our center. Pre-operative cardiac gated CT images were utilized to create a 3D printed model with true size aortic root dimensions, including the coronary artery ostium location and left ventricular outflow tract. Deployment of the corresponding model and size TAVI valve into the created 3D model at a similar depth of implantation via fluoroscopy was performed for each patient. Degree of PVL was assessed using a closed system with water infusion under pressure over a duration of 5 s. Correlation was made between the volume obtained in the closed loop model during the pressurized period and the degree of PVL reported on the patients post TAVI placement on transthoracic echocardiogram.

Results

One female, and four males (age in years ranged from 68 to 87) underwent successful TAVI (0% 30-day mortality). PVL on post procedure TTE ranged from none to trivial. Successful deployment of TAVI valves inside the 3D model occurred in all cases. The average volume of water collected on three trials over 5 s ranged between 19.1–24.1 ml A multivariate linear regression showed significant association between the degree of PVL reported on post-operative transthoracic echocardiogram and the amount of volume detected in the 3D model (difference: -3.9657, 95% CI: (− 4.6761,-3.2554), p < 0.001).

Conclusions

Our experiments show that replicated 3D models have potential clinical utilization in predicting PVL in the TAVI population. Future research into the role of 3D modelling in the field of TAVI should continue to be explored.

Determinants of effective orifice area in aortic valve replacement: anatomic and clinical factors

Background

Obtaining adequate effective orifice area (EOA) in surgical aortic valve replacement (SAVR) is important to minimize pressure gradients across the prosthetic aortic valve (AV) and improve clinical outcomes. However, the predictors of EOA are unclear.

Methods

From July 2011 to March 2016, patients undergoing SAVR who were preoperatively evaluated using a computed tomography (CT) on the aortic root were enrolled. Indexed EOA (iEOA) was used as an indicator of prosthetic AV opening area. The aortic root parameters investigated were the annular diameter (max and min), annular perimeter, annular area, and maximal dimensions of the proximal ascending aorta. These variables were evaluated as predictors of EOA, and an individual surgeon was incorporated in analysis for verifying surgeon dependent factors.

Results

Among the 710 patients included in this study [age: 64.9±10.8 years; females: n=285 (40.1%)], 370 (52.1%) were implanted with bio-prosthesis. Mean prosthetic iEOA was 1.1±0.3 cm²/m². Univariable linear regression analysis showed that all indexed aortic root parameters (maximal and minimal annular diameters, annular perimeter, annular area, and sinus dimensions) were significantly associated with iEOA (P<0.001). Multivariable analysis showed that indexed aortic annular area, indexed maximal diameter of the Valsalva sinus, female sex, and bio-prosthesis, supra-annular type prosthesis and surgeon were significant and independent determinants of iEOA (adjusted R²=0.513, P<0.001).

Conclusions

Aortic annular area and Valsalva sinus diameter are independent determinants for iEOA measured by preoperative CT; surgeon-dependent factors are also significant determinants in SAVR.

Imaging for Predicting and Assessing Prosthesis-Patient Mismatch After Aortic Valve Replacement

Prosthesis-patient mismatch (PPM) occurs when the effective orifice area (EOA) of the prosthetic valve is too small in relation to a patient's body size, thus resulting in high residual postoperative pressure gradients across the prosthesis. Severe PPM occurs in 2% to 20% of patients undergoing surgical aortic valve replacement (AVR) and is associated with 1.5- to 2.0-fold increase in the risk of mortality and heart failure rehospitalization. The purpose of this article is to present an overview of the role of multimodality imaging in the assessment, prediction, prevention, and management of PPM following AVR. The risk of PPM can be anticipated at the time of AVR by calculating the predicted indexed from the normal reference value of EOA of the selected prosthesis and patient's body surface area. The strategies to prevent PPM at the time of surgical AVR include: 1) implanting a newer generation of prosthetic valve with better hemodynamic; 2) enlarging the aortic root or annulus to accommodate a larger prosthetic valve; or 3) performing TAVR rather than surgical AVR. The identification and quantitation of PPM as well as its distinction versus prosthetic valve stenosis is primarily based on transthoracic echocardiography, but important information may be obtained from other imaging modalities such as transesophageal echocardiography and multidetector computed tomography. PPM is characterized by high transprosthetic velocity and gradients, normal EOA, small indexed EOA, and normal leaflet morphology and mobility. Transesophageal echocardiography and multidetector computed tomography are particularly helpful to assess prosthetic valve leaflet morphology and mobility, which is a cornerstone of the differential diagnosis between PPM and pathologic valve obstruction. Severe symptomatic PPM following AVR with a bioprosthetic valve may be treated by redo surgery or the transcatheter valve-in-valve procedure with fracturing of the surgical valve stent.

Utility of conventional aortic root shot angiography for SAPIEN 3 prosthesis sizing in TAVI: feasibility and inter-reader variability

Background

The gold-standard approach to prosthesis sizing before transcatheter aortic valve implantation (TAVI) is multislice computed tomography (MSCT). We aimed to investigate whether conventional aortic root angiography (CA) alone can reliably facilitate valve selection and to describe its inter-reader variability.

Methods

Five TAVI specialists (3 interventional cardiologists and 2 cardiac surgeons) independently reviewed preprocedural CAs for 50 patients implanted with the Edwards SAPIEN 3 valve.

Results

The prosthesis size selected based on visual CA appraisal matched that based on MSCT in 60% of cases (range: 50%–68%), with undersizing in 11% (4%–33%) and oversizing in 29% (10%–46%; p=0.187 for equality of the proportions test). Agreement between CA-based and MSCT-based valve selection was moderate (K=0.41; Kw=0.61). Reassessment of choice following awareness of the annulus long-axis diameter did not significantly improve this agreement (0.40 and 0.63, respectively), though more undersizing (14%) and less oversizing (25%) occurred. Correct valve selection was more common in interventional cardiologists than cardiac surgeons (66% vs 53%; p=0.0391), who made more oversizing errors.

Conclusions

There is a modest agreement between CA-based and MSCT-based SAPIEN 3 selection. Although the former should not be performed routinely, it may be informative in settings where MSCT and transoesophageal echocardiography are unavailable.

The contemporary role of echocardiography in the assessment and management of aortic stenosis

Aortic stenosis (AS) represents a major healthcare issue because of its ever-increasing prevalence, poor prognosis, and complex pathophysiology. Echocardiography plays a central role in providing a comprehensive morphological and hemodynamic evaluation of AS. The diagnosis of severe AS is currently based on three hemodynamic parameters including maximal jet velocity, mean pressure gradient (mPG) across the aortic valve, and aortic valve area (AVA). However, inconsistent grading of AS severity is common when the AVA is < 1.0 cm² but the mPG is < 40 mmHg, also known as low-gradient AS (LGAS). Special attention should be paid to patients with symptomatic LGAS with low stroke volume and/or low ejection fraction because this entity is more difficult to diagnose and has a worse prognosis. Stress echocardiography testing plays an important role in this disease entity. Elderly patients with prohibitive comorbidities for surgical aortic valve replacement (AVR) were without procedural options until the advent of transcatheter AVR (TAVR), which has dramatically changed these circumstances. Along with computed tomography, echocardiography plays a vital role in the periprocedural assessment of the aortic valve and surrounding apparatus. This review describes the evolution of the role of echocardiography in the diagnosis and management of AS, the complexity of the aortic apparatus, and the increased need for expert use of three-dimensional echocardiography.

Computed tomography angiography is not accurate in predicting surgical prosthetic aortic valve implant size

BACKGROUND

Multidetector computed tomography is vital in preoperative sizing for transcatheter aortic valve replacement. The purpose of this study is to determine whether preoperative transcatheter aortic valve replacement multidetector computed tomography accurately predicts surgical aortic valve prosthesis size.

METHODS

Between July 2012 and July 2017, 102 patients who underwent surgical aortic valve replacement had preoperative aortic valve sizing by multidetector computed tomography. The aortic annulus diameter calculated using multidetector computed tomography was compared with intraoperative valve sizing during surgical aortic valve replacement.

RESULTS

Forty-one (40.2%) of the 102 patients studied had multidetector computed tomography aortic valve measurements that were accurate. Implanted valves were smaller than multidetector computed tomography calculation in 40 patients (39.2%) and were larger in 21 patients (20.6%). Multidetector computed tomography measurements remained inconsistent with intraoperative sizing regardless of aortic annulus diameter. The variance between multidetector computed tomography annulus measurements and intraoperative sizing was statistically significant.

CONCLUSIONS

Preoperative aortic annulus measurements by our institutional transcatheter aortic valve replacement multidetector computed tomography protocol differed substantially from surgical implant size. There was no trend toward over nor under sizing for the entire cohort. However, patients with large measured annulus diameter were more likely to have a smaller valve implanted than predicted, and patients with small measured annulus diameter were more likely to have a larger valve implanted than predicted. These results may affect preoperative planning for patients undergoing aortic valve replacement.

Preoperative aortic annulus size assessment by transthoracic echocardiography compared to the size of surgically implanted aortic prostheses

Objectives

The aortic annulus diameter measured by transthoracic echocardiography yields lower values than by computed tomography, and echo-based selection of transcatheter aortic valve prosthesis size has been implied to result in more frequent paravalvular leakage. We investigated the relation of preoperative annulus diameter by echo with the ring size of the aortic prosthesis chosen by direct assessment during open-heart aortic valve replacement.

Methods

Preoperative annulus diameter by echo (from parasternal long-axis cross-sections of the left ventricular outflow tract and aortic valve) and implanted prosthetic diameter (tissue annulus diameter, determined intraoperatively using a sizing instrument) were compared retrospectively in 285 consecutive patients undergoing open-heart aortic valve replacement.

Results

A total of 285 prostheses (240 biologic and 45 mechanical) were implanted, with prosthetic diameter ranging between 19 and 27 mm. There was a significant linear correlation (P < 0.0001) with r = 0.51, between preoperative annulus diameter by echo (mean 21.8 ± 2.8 mm) and prosthetic diameter (22.9 ± 1.7 mm). Preoperative annulus diameter of patients receiving prostheses no. 21, 23 and 25 mm aortic prostheses (the most frequent prosthesis sizes) were significantly different (P < 0.001) from each other. On average, preoperative annulus diameter by echo underestimated prosthetic diameter by a bias of 1.07 mm.

Conclusion

Our data confirm that preoperative echo assessment of the aortic valve may slightly underestimates the optimal surgical prosthesis diameter for the aortic valve annulus.

Highly Accelerated Breath-Hold Noncontrast Electrocardiographically- and Pulse-Gated Balanced Steady-State Free Precession Magnetic Resonance Angiography of the Thoracic Aorta: Comparison With Electrocardiographically-Gated Computed Tomographic Angiography

OBJECTIVE

The aim of this study was to evaluate agreement of measured thoracic aortic caliber in patients with aortic disease, using electrocardiographically-(ECG) and pulse-gated breath-hold noncontrast balanced steady-state free precession MRA (ECG-MRA, P-MRA) at 1.5 T, compared with ECG-gated computed tomographic angiography (CTA).

METHODS

Thirty-one patients underwent ECG-MRA, P-MRA, and CTA. Two readers independently measured aortic caliber in 7 segments, with agreement between techniques and readers evaluated. Image quality was qualitatively assessed.

RESULTS

There was overall excellent agreement among ECG-MRA, P-MRA, and CTA for measured aortic caliber (Lin's concordance correlation coefficient ≥0.94, all comparisons); however, lower concordance was noted at the annulus (Lin's concordance correlation coefficient <0.6) at segmental assessment. There was excellent interreader agreement for aortic caliber for all 3 techniques (intraclass correlation coefficient >0.94). Image quality was poorer for both MRA techniques compared with CTA, particularly at the aortic root.

CONCLUSIONS

Electrocardiographically-gated MRA and P-MRA at 1.5 T achieve comparable thoracic aortic measurements to gated CTA in clinical patients, despite inferior image quality.

The Pivotal Role of Imaging in TAVR Procedures

PURPOSE OF REVIEW

Transcatheter aortic valve replacement (TAVR) is underpinned by an array of imaging techniques designed to not only select an appropriately sized implant but also to identify potential obstacles to procedural success. This review presents currently important aspects of TAVR imaging, describing the salient features of each modality as well as recent developments in the field.

RECENT FINDINGS

The latest data on TAVR outcomes reflects the increasing experience of operators and the significant role of pre-procedural imaging. Debate continues as to which modality sizes the aortic annulus most accurately, 3D transoesophageal echocardiography (TEE) or MDCT, as well as to whether the merits of real-time peri-procedural 3D imaging guidance outweigh the possible adverse consequences of general anaesthesia which is requisite for intraprocedural 3D TEE. TAVR is now largely based on pre-acquired roadmaps of the truncal vasculature and intense pre-procedural planning. TEE and Multi-detector computed tomography (MDCT) have been shown to perform similarly in annulus sizing. However, given the complexity of many TAVR patients and the importance of identifying the most suitable pathway to the valve as well as any potentially confounding other structural or functional heart disease, both modalities remain relevant in current TAVR.

Accuracy and usefulness of aortic annular measurement using real-time three-dimensional transesophageal echocardiography: Comparison with direct surgical sizing

BACKGROUND

There is a paucity of data that demonstrates a clinical impact of anatomical measurements of the aortic annulus by three-dimensional (3D) transesophageal echocardiography (TEE) on surgical aortic valve replacement (AVR). The aim of this study is to validate the accuracy of 3D TEE measurements compared with the direct intraoperative annular diameter and to investigate an impact of 3D TEE on a prediction of AVR with aortic annular enlargement (AAE).

METHODS AND RESULTS

We retrospectively enrolled 61 patients who underwent both two-dimension (2D) and 3D TEE and transthoracic echocardiography (TTE) before AVR. The annular diameters were measured noninvasively with 2D TEE (D_2D) and TTE (D_TTE) in a classical manner and the area- and perimeter-derived annular diameters (D_area, D_perim) were measured from using 3D TEE analysis. Intraoperative annular diameter was measured with the manufacture's sizer (D_intraope). D_area showed the best agreement with D_intraope in the Bland-Altman analysis. D_area, D_perim, D_2D, and D_TTE correlated well with D_intraope (r=0.821, 0.820, 0.532, and 0.610, respectively; all p<0.001). Three patients underwent AVR with AAE and the specificity of D_perim for prediction of AAE was significantly higher than D_2D (p=0.008).

CONCLUSIONS

3D TEE measurement of aortic annular diameter showed better agreement with the direct intraoperative measurement than 2D TEE and TTE measurements. 3D TEE measurement could predict AVR with AAE more accurately than 2D TEE and TTE measurements.

Aortic Valve Annular Sizing: Intraoperative Assessment Versus Preoperative Multidetector Computed Tomography

BACKGROUND

Appropriate valve sizing is critical in aortic valve replacement. We hypothesized that direct intraoperative valve sizing results in smaller aortic annular diameters compared with sizing based on systolic-phase multidetector computerized tomographic (MDCT) imaging.

METHODS AND RESULTS

We retrospectively analyzed 78 patients undergoing surgical aortic valve replacement for severe aortic stenosis between 2012 and 2014 at our institution. Preoperative MDCT measurements of the aortic annulus served as basis for assignment to a theoretical surgical valve size, which was then (1) compared to the implanted valve size and (2) to a theoretical transcatheter aortic valve replacement valve size. To quantify the resulting differences, geometric orifice areas (GOA) were calculated. MDCT-based sizing produced the same valve size for n=34 patients (group CT-same), a larger valve with a 25% increased GOA in n=32 patients (group CT-Lg) and a smaller GOA by 22% in n=12 patients (group CT-Sm). On the basis of MDCT measurements, 41% of valves implanted were undersized. The comparison of intraoperative implanted to a theoretical transcatheter aortic valve replacement valve size resulted in GOAs 25% larger for patients in group CT-same, 40.6% larger in group CT-Lg and 14.6% larger in group CT-Sm.

CONCLUSIONS

Preoperative MDCT measurements differ substantially from direct intraoperative assessment of the aortic annulus. Implanted surgical aortic valve replacement valves were smaller relative to MDCT-based sizing in 41% of patients, and the potential GOA was between 25% and 40.6% larger if patients had undergone transcatheter aortic valve replacement.

Patient selection for transcatheter aortic valve replacement: A combined clinical and multimodality imaging approach

Transcatheter aortic valve replacement (TAVR) has been validated as a new therapy for patients affected by severe symptomatic aortic stenosis who are not eligible for surgical intervention because of major contraindication or high operative risk. Patient selection for TAVR should be based not only on accurate assessment of aortic stenosis morphology, but also on several clinical and functional data. Multi-Imaging modalities should be preferred for assessing the anatomy and the dimensions of the aortic valve and annulus before TAVR. Ultrasounds represent the first line tool in evaluation of this patients giving detailed anatomic description of aortic valve complex and allowing estimating with enough reliability the hemodynamic entity of valvular stenosis. Angiography should be used to assess coronary involvement and plan a revascularization strategy before the implant. Multislice computed tomography play a central role as it can give anatomical details in order to choice the best fitting prosthesis, evaluate the morphology of the access path and detect other relevant comorbidities. Cardiovascular magnetic resonance and positron emission tomography are emergent modality helpful in aortic stenosis evaluation. The aim of this review is to give an overview on TAVR clinical and technical aspects essential for adequate selection.

Assessment of Paravalvular Leak After Transcatheter Aortic Valve Replacement: Transesophageal Echocardiography Compared With Transthoracic Echocardiography

OBJECTIVES

Determine whether moderate or greater paravalvular leak (PVL) after transcatheter aortic valve replacement quantified using intraoperative transesophageal echocardiography (TEE) is associated with mortality and investigate the correlation between PVL grading using intraoperative TEE and postoperative transthoracic echocardiography (TTE).

DESIGN

Retrospective, observational study.

SETTING

Single academic institution.

PARTICIPANTS

The study comprised adult patients undergoing elective transcatheter aortic valve replacement between April 2011 and February 2014.

INTERVENTIONS

Patients were grouped by amount of PVL on intraoperative TEE into "significant" (moderate or greater) and "nonsignificant" (no, trivial, or mild) PVL groups. Demographics and patient characteristics were compared. Continuous variables were assessed with t-tests or Wilcoxon rank sum tests and categorical variables with the chi-square or Fisher exact test. A Cox proportional hazards model adjusted for EuroSCORE was used to test the independent association of PVL with late mortality, and covariate-adjusted survival curves were constructed. A Fleiss-Cohen-weighted kappa value was used to assess agreement between PVL grading using intraoperative TEE and postoperative TTE.

MEASUREMENTS AND MAIN RESULTS

One hundred ninety-six patients were grouped into the "significant" (n = 22) or "nonsignificant" (n = 174) PVL group. Twenty patients (10%) died during the follow-up period. Significant PVL on either TTE (p = 0.62, hazard ratio 1.68, 95% confidence interval [CI] 0.22-12.85) or TEE (p = 0.49, hazard ratio 0.49; 95% CI 0.06-3.68) was not associated with a survival difference. Modest agreement was found between PVL on intraoperative TEE and postoperative TTE (kappa = 0.47, CI 0.37-0.57, p < 0.0001).

CONCLUSIONS

Larger studies are needed to evaluate the association of PVL graded on intraoperative TEE with survival. There is modest agreement between the degree of PVL found on TEE and TTE.

3D transoesophageal echocardiography in the TAVI sizing arena: should we do it and how do we do it?

Transcatheter aortic valve implantation (TAVI) was initially proven as an alternative to valve replacement therapy in those beyond established risk thresholds for conventional surgery. With time the technique has been methodically refined and offered to a progressively lower risk cohort, and with this evolution has come that of the significant imaging requirements of valve implantation. This review discusses the role of transoesophageal echocardiography (TOE) in the current TAVI arena, aligning it with that of cardiac computed tomography, and outlining how TOE can be used most effectively both prior to and during TAVI in order to optimise outcomes.

Fully Automatic 3-D-TEE Segmentation for the Planning of Transcatheter Aortic Valve Implantation

A novel fully automatic framework for aortic valve (AV) trunk segmentation in three-dimensional (3-D) transesophageal echocardiography (TEE) datasets is proposed. The methodology combines a previously presented semiautomatic segmentation strategy by using shape-based B-spline Explicit Active Surfaces with two novel algorithms to automate the quantification of relevant AV measures. The first combines a fast rotation-invariant 3-D generalized Hough transform with a vessel-like dark tube detector to initialize the segmentation. After segmenting the AV wall, the second algorithm focuses on aligning this surface with the reference ones in order to estimate the short-axis (SAx) planes (at the left ventricular outflow tract, annulus, sinuses of Valsalva, and sinotubular junction) in which to perform the measurements. The framework has been tested in 20 3-D-TEE datasets with both stenotic and nonstenotic AVs. The initialization algorithm presented a median error of around 3 mm for the AV axis endpoints, with an overall feasibility of 90%. In its turn, the SAx detection algorithm showed to be highly reproducible, with indistinguishable results compared with the variability found between the experts' defined planes. Automatically extracted measures at the four levels showed a good agreement with the experts' ones, with limits of agreement similar to the interobserver variability. Moreover, a validation set of 20 additional stenotic AV datasets corroborated the method's applicability and accuracy. The proposed approach mitigates the variability associated with the manual quantification while significantly reducing the required analysis time (12 s versus 5 to 10 min), which shows its appeal for automatic dimensioning of the AV morphology in 3-D-TEE for the planning of transcatheter AV implantation.

Aortic Valve Tract Segmentation From 3D-TEE Using Shape-Based B-Spline Explicit Active Surfaces

A novel semi-automatic algorithm for aortic valve (AV) wall segmentation is presented for 3D transesophageal echocardiography (TEE) datasets. The proposed methodology uses a 3D cylindrical formulation of the B-spline Explicit Active Surfaces (BEAS) framework in a dual-stage energy evolution process, comprising a threshold-based and a localized region-based stage. Hereto, intensity and shape-based features are combined to accurately delineate the AV wall from the ascending aorta (AA) to the left ventricular outflow tract (LVOT). Shape-prior information is included using a profile-based statistical shape model (SSM), and embedded in BEAS through two novel regularization terms: one confining the segmented AV profiles to shapes seen in the SSM (hard regularization) and another penalizing according to the profile's degree of likelihood (soft regularization). The proposed energy functional takes thus advantage of the intensity data in regions with strong image content, while complementing it with shape knowledge in regions with nearly absent image data. The proposed algorithm has been validated in 20 3D-TEE datasets with both stenotic and non-stenotic valves. It was shown to be accurate, robust and computationally efficient, taking less than 1 second to segment the AV wall from the AA to the LVOT with an average accuracy of 0.78 mm. Semi-automatically extracted measurements at four relevant anatomical levels (LVOT, aortic annulus, sinuses of Valsalva and sinotubular junction) showed an excellent agreement with experts' ones, with a higher reproducibility than manually-extracted measures.

Upper gastrointestinal bleeding following transcatheter aortic valve replacement: A retrospective analysis

OBJECTIVES

The aim of this study was to identify the incidence of upper gastrointestinal bleeding (UGIB) in the postprocedural period following transcatheter aortic valve replacement (TAVR).

BACKGROUND

As TAVR moves into intermediate- and low-risk patients, it has become increasingly important to understand its extracardiac complications. The patient population undergoing TAVR have clinical and demographic characteristics that place them at significant risk of UGIB. Practical aspects of TAVR, including use of antithrombotic therapy, further increase risk of UGIB.

METHODS

A retrospective single-center evaluation of 841 patients who underwent TAVR between January 2005 and August 2014 was performed in conjunction with analysis of referral patterns to the gastroenterology service for UGIB at the same site.

RESULTS

The overall risk of UGIB following TAVR was found to be 2.0% (n = 17/841). Additionally, the risk of UGIB in patients receiving triple antithrombotic therapy was found to be 10-fold greater than patients not receiving triple antithrombotic therapy (11.8% vs 1.0%). Endoscopy findings demonstrated five high-risk esophageal lesions including erosive esophageal ulcers, visible vessels at the GE junction, erosions at distal esophagus, and an actively bleeding esophageal ring that had been intubated through by the transesophageal echocardiography (TEE) probe.

CONCLUSIONS

This large cohort study demonstrates that TAVR is associated with a moderate risk of severe UGIB. The results of this study suggest that patients on triple antithrombotic therapy are at highest risk for severe UGIB. © 2016 Wiley Periodicals, Inc.

The Role of Imaging in Aortic Valve Disease

PURPOSE OF REVIEW

Aortic valve disease is the most common form of heart valve disease in developed countries. Imaging remains central to the diagnosis and risk stratification of patients with both aortic stenosis and regurgitation and has traditionally been performed with echocardiography. Indeed, echocardiography remains the cornerstone of aortic valve imaging as it is cheap, widely available and provides critical information concerning valve hemodynamics and ventricular function.

RECENT FINDINGS

Whilst diagnostic in the vast majority of patients, echocardiography has certain limitations including operator variability, potential for measurement errors and internal inconsistencies in severity grading. In particular, low-gradient severe aortic stenosis is common and challenging to diagnose. Aortic valve imaging may therefore be improved with alternative and complimentary multimodality approaches.

SUMMARY

This review investigates established and novel techniques for imaging both the aortic valve and the myocardial remodelling response including echocardiography, computed tomography, cardiovascular magnetic resonance and positron emission tomography. Moreover, we examine how the complementary information provided by each modality may be used in both future clinical practice and the research arena.

Cardiovascular magnetic resonance as a reliable alternative to cardiovascular computed tomography and transesophageal echocardiography for aortic annulus valve sizing

To assess the accuracy and reproducibly of cardiovascular magnetic resonance (CMR) in the measurement of the aortic annulus and in process of valve sizing as compared to intra-operative sizing, cardiovascular computed tomography (CCT) and transesophageal echocardiography (TEE). Retrospective study on 42 patients who underwent aortic valve replacement from September 2010 to September 2015, with available records of pre surgery annulus assessment by CMR, CCT and TEE and of peri-operative assessment. In CCT and CMR, the annular plane was considered a virtual ring formed by the lowest hinge points of the valvular attachments to the aorta. In TEE the annulus was measured at the base of leaflet insertion in the mid-esophageal long-axis view using the X-plane technique. Two double-blinded operators performed the assessments for each imaging technique. Intra-operative evaluation was performed using Hegar dilators. Continuous variables were studied with within-subject ANOVA, Bland-Altman (BA) plots, Wilcoxon's and Friedman's tests; trends were explored with scatter plots. Categorical variables were studied with Fisher's exact test. The intra- and inter-operator reliability was satisfying. There were no significant differences between the annulus dimensions measured by CMR and either one of the three references. Valve sizing for CoreValve by CMR had the same good agreement with CCT and TEE, with a 78 % match rate; for SAPIEN XT the agreement was slightly better (82 %) for CCT than for TEE (66 %). MR performs well when compared to the surgical reference of intra-operative sizing and stands up to the level of the most used imaging references (CCT and TEE).

Cyclic changes in area- and perimeter-derived effective dimensions of the aortic annulus measured with multislice computed tomography and comparison with metric intraoperative sizing

AIMS

Multislice computed tomography (MSCT) is recommended for annular sizing prior to transcatheter aortic valve implantation (TAVI), but it remains unclear whether systolic or diastolic reconstructions should be used and whether the effective annular diameter should be derived by area or perimeter. In this study these different approaches were compared with intraoperative sizing.

METHODS

In 52 patients who were evaluated but deemed unsuitable for TAVI, the annulus was measured during conventional surgery using metric sizers (AnnOp) and compared with MSCT measurements (cross-sectional diameter derived by area [AnnAsys, AnnAdia; AnnAmean = (AnnAsys + AnnAdia)/2] and perimeter (AnnPsys, AnnPdia) in systole and diastole). Furthermore, TAVI was simulated based on AnnOp and the impact of the various MSCT approaches on sizing strategy was determined.

RESULTS

The best agreement with AnnOp [mean difference (limits of agreement)] was shown for AnnAmean [0.03 mm (-1.9 to 1.96)], whereas the strongest deviation was noted for AnnPsys [-1.08 mm (-3.01 to 0.86)]. Mean differences between systole and diastole were significant but small: 0.82 mm (3.5 %) for area- and 0.81 mm (3.3 %) for perimeter-derived measurements. Simulation of TAVI revealed the least change of strategy for AnnAmean (76.9 %) as compared with AnnPsys (53.8 %); between AnnAsys and AnnAdia sizing would have been deviant in 17.3 % due to relatively large intraindividual cyclic differences.

CONCLUSIONS

AnnAmean demonstrated the best agreement with AnnOp, whereas perimeter-derived measurements were somewhat overestimated. Despite a negligible average difference between systolic and diastolic annular values, in a subset of patients the intraindividual cyclic variability was relatively large and potentially of clinical impact.