Multimodality Quantitative Imaging of Aortic Root for Transcatheter Aortic Valve Implantation

Misidentification of the True Aortic Annulus With 2-dimensional Echocardiography: A Critical Appraisal Using 3-Dimensional Imaging

OBJECTIVES

This study aimed to evaluate the accuracy of identifying the true aortic valve (AV) annulus using 2-dimensional (2D) echocardiography, with the goal of highlighting potential misidentification issues in clinical practice.

DESIGN

An observational study employing 3-dimensional (3D) datasets to generate 2D images of the AV annulus for analysis.

SETTING

The study was conducted in an academic medical center.

PARTICIPANTS

Three-dimensional transesophageal echocardiography datasets were obtained from 11 patients with normal AV and aortic root anatomies undergoing coronary artery bypass surgery. Attending anesthesiologists certified by the National Board of Echocardiography (NBE) were approached subsequently to participate in this study.

INTERVENTIONS

Two images per patient were generated from 3D datasets, reflecting the mid-esophageal long-axis view of the AV, a true AV annulus image, and an off-axis image. A survey was distributed to NBE-certified perioperative echocardiographers across 12 academic institutions to identify the true AV annulus from these images.

MEASUREMENTS AND MAIN RESULTS

The survey, completed by 45 qualified respondents, revealed a significant misidentification rate of the true AV annulus, with only 36.8% of responses correctly identifying it. The rate of correct identification varied across image sets, with 44.4% of participants unable to correctly identify any true AV annulus image.

CONCLUSIONS

The study highlighted the limitations of 2D echocardiography in accurately identifying the true AV annulus in complex 3D structures like the aortic root. The findings suggest a need for greater reliance on advanced imaging modalities, such as 3D echocardiography, to improve accuracy in clinical practice.

Recommendations in pre-procedural imaging assessment for TAVI intervention: SIC-SIRM position paper part 2 (CT and MR angiography, standard medical reporting, future perspectives)

Non-invasive cardiovascular imaging owns a pivotal role in the preoperative assessment of patient candidates for transcatheter aortic valve implantation (TAVI), providing a wide range of crucial information to select the patients who will benefit the most and have the procedure done safely. This document has been developed by a joined group of experts of the Italian Society of Cardiology and the Italian Society of Medical and Interventional Radiology and aims to produce an updated consensus statement about the pre-procedural imaging assessment in candidate patients for TAVI intervention. The writing committee consisted of members and experts of both societies who worked jointly to develop a more integrated approach in the field of cardiac and vascular radiology. Part 2 of the document will cover CT and MR angiography, standard medical reporting, and future perspectives.

Three-dimensional echocardiographic assessment of the aortic valve and the aorta

We describe the role of three-dimensional echocardiography in the assessment of the aortic valve and the aorta. The manuscript is heavily illustrated with figures and movie clips.

Two-dimensional transesophageal echocardiography for aortic annular sizing in patients undergoing transcatheter aortic valve implantation

Background

Accurate preoperative assessment of the aortic annulus dimension is crucial for successful transcatheter aortic valve implantation (TAVI). In this study we examined the accuracy of a novel method using two-dimensional transesophageal echocardiography (2D-TEE) for measurement of the aortic annulus.

Methods

We evaluated the theoretical impact of the measurement of the annulus diameter and area using the circumcircle of a triangle method on the decision to perform the procedure and choice of the prosthesis size.

Results

Sixty-three consecutive patients were scheduled for TAVI. Mean age was 82 ± 4 years, and 25 patients (55.6 %) were female. Mean aortic annulus diameter was 20.3 ± 2.2 mm assessed by TEE on the mid-esophageal long-axis view and 23.9 ± 2.3 mm using CT (p < 0.001). There was a tendency for the TEE derived areas using the new method to be higher (p < 0.001). The TEE measurements were on average 42.33 mm² higher than the CT measurements without an evidence of a systematic over- or under-sizing (p = 1.00). Agreement between TEE and CT chosen valve sizes was good overall (kappa = 0.67 and weighted kappa = 0.71). For patients who turned out to have no AR, the two methods agreed in 84.6 % of patients.

Conclusions

CT remanis the gold standard in sizing of the aortic valve annulus. Nevertheless, sizing of the aortic valve annulus using TEE derived area may be helpful. The impact of integration of this method in the algorithm of aortic annulus sizing on the outcome of patients undergoing TAVI should be examined in future studies.

Accuracy of Aortic Annulus Diameter Measurement: Comparison of Multi-Detector CT, Two- and Three-Dimensional Echocardiography

OBJECTIVE

Accurate preprocedural quantification of the aortic annulus diameter is crucial for the operative success of the aortic valve surgery and especially transcatheter aortic valve replacement (TAVR). We conducted a prospective study to compare the accuracy of preoperative aortic annulus measurements using different imaging methods and direct measurements for aortic valve surgery.

METHODS

We enrolled 52 patients who underwent open aortic valve surgery between March 2012 and March 2014. Aortic annulus diameter was prospectively measured by transthoracic two-dimensional echocardiography (2D-TTE), transesophageal three-dimensional echocardiography (3D-TEE), and multi-detector computed tomography (MDCT). Imaging measurements were performed blindly by lab technicians. At surgery, the aortic annulus diameter was directly measured.

RESULTS

Of the three methods, MDCT provided the smallest error in determining aortic annulus size as compared with the measurements at surgery. The limit of agreement of the aortic diameter by MDCT was smallest in the present study.

CONCLUSIONS

The MDCT provided the most accurate measurement of aortic annulus diameter compared with 2D-TTE and 3D-TEE.

Feasibility of a new method using two-dimensional transesophageal echocardiography for aortic annular sizing in patients undergoing transcatheter aortic valve implantation; a case-control study

Background

Accurate preoperative assessment of the aortic annulus dimension is crucial for successful transcatheter aortic valve implantation (TAVI). In this study we validated a new method using two-dimensional transesophageal echocardiography (2D-TEE) for measurement of the aortic annulus prior to TAVI.

Methods

We analysed 124 patients who underwent successful TAVI using a self-expandable prosthesis, divided equally into two groups; in the study group we used the cross sectional short axis 2D-TEE for measurement of the aortic annulus and in the control group we used the long axis 2D-TEE.

Results

Both groups were comparable regarding the clinical parameters. On the other hand, patients in the study group had less left ventricular ejection fraction (38.9 % versus 45.6 %, p = 0.01). The aortic valve annulus was, although not statistically significant, smaller in the study group (21.58 versus 23.28 mm, p = 0.25).

Post procedural quantification of the aortic regurgitation revealed that only one patient in both groups had severe aortic regurgitation (AR), in this patient the valve was implanted deep. The incidence of significant AR was higher in the control group (29.0 % versus 12.9 %, p = 0.027).

Conclusions

Sizing of the aortic valve annulus using cross-sectional 2D-TEE offers a safe and plausible method for patients undergoing TAVI using the self-expandable prosthesis and is significantly superior to using long axis 2D-TEE.

Multidimensional MDCT angiography in the context of transcatheter aortic valve implantation

OBJECTIVE

Transcatheter aortic valve implantation has emerged as a viable treatment alternative for patients with severe aortic stenosis who are not surgical candidates. Multidimensional (3D and 4D) MDCT angiography plays a critical role in the safety, success, and outcome of an institutional transcatheter aortic valve implantation program.

CONCLUSION

Given the increasing therapeutic role of this innovative technique, an understanding of essential imaging concepts in its context is critical for appropriate image acquisition and interpretation.

Standardized imaging for aortic annular sizing: implications for transcatheter valve selection

The safety and efficacy of transcatheter aortic valve replacement procedures are directly related to proper imaging. This report revisits the existing noninvasive and invasive approaches that have concurrently evolved to meet the demands for optimal selection and guidance of patients undergoing transcatheter aortic valve replacement. The authors summarize the published evidence and discuss the strengths and pitfalls of echocardiographic, computed tomographic, and calibrated aortic balloon valvuloplasty techniques in sizing the aortic valve annulus. Specific proposals for 3-dimensional tomographic reconstructions of complex 3-dimensional aortic root anatomy are provided for reducing intermodality variability in annular sizing. Finally, on the basis of the sizing approaches discussed in this review, the authors provide practical recommendations for balloon-expandable and self-expandable prostheses selection. Strategic use of echocardiographic, multislice computed tomographic, and angiographic data may provide complementary information for determining the anatomical suitability, efficacy, and safety of the procedure.

Sizing the aortic annulus

Transcatheter aortic valve implantation (TAVI) is a valuable alternative for aortic valve replacement in selected high-risk candidates. Accurate preoperative assessment of the aortic annular dimensions is crucial for the success of TAVI, since choice of an incorrectly sized prosthesis may result in catastrophic complications. These complications include annular rupture and coronary arterial obstruction, if the prosthesis is too big, or prosthesis migration and severe paravalvular leakage, if the prosthesis is too small. According to current recommendations, the choice of prosthesis size is based on transoesophageal echocardiography (TEE) measurements. However, TEE results are dependent on operator experience. Moreover, recent research has shown that TEE can significantly underestimate annular dimensional measurements. Alternative sizing methods based on Multidetector Computed Tomography (MDCT) or manometry during balloon aortic valvuloplasty have therefore been developed. We present a brief overview of the imaging modalities available for preoperative assessment of annular size and discuss their potential advantages and limitations.

Cardiovascular magnetic resonance for the assessment of patients undergoing transcatheter aortic valve implantation: a pilot study

BACKGROUND

Before trans-catheter aortic valve implantation (TAVI), assessment of cardiac function and accurate measurement of the aortic root are key to determine the correct size and type of the prosthesis. The aim of this study was to compare cardiovascular magnetic resonance (CMR) and trans-thoracic echocardiography (TTE) for the assessment of aortic valve measurements and left ventricular function in high-risk elderly patients submitted to TAVI.

METHODS

Consecutive patients with severe aortic stenosis and contraindications for surgical aortic valve replacement were screened from April 2009 to January 2011 and imaged with TTE and CMR.

RESULTS

Patients who underwent both TTE and CMR (n = 49) had a mean age of 80.8 ± 4.8 years and a mean logistic EuroSCORE of 14.9 ± 9.3%. There was a good correlation between TTE and CMR in terms of annulus size (R2 = 0.48, p < 0.001), left ventricular outflow tract (LVOT) diameter (R2 = 0.62, p < 0.001) and left ventricular ejection fraction (LVEF) (R2 = 0.47, p < 0.001) and a moderate correlation in terms of aortic valve area (AVA) (R2 = 0.24, p < 0.001). CMR generally tended to report larger values than TTE for all measurements. The Bland-Altman test indicated that the 95% limits of agreement between TTE and CMR ranged from -5.6 mm to + 1.0 mm for annulus size, from -0.45 mm to + 0.25 mm for LVOT, from -0.45 mm2 to + 0.25 mm2 for AVA and from -29.2% to 13.2% for LVEF.

CONCLUSIONS

In elderly patients candidates to TAVI, CMR represents a viable complement to transthoracic echocardiography.

Aortic valve calcium score as a predictor for outcome after TAVI using the CoreValve revalving system

BACKGROUND

TAVI is a novel treatment option for patients at too high risk for surgery. Risk scores for surgical valve replacement failed to accurately predict outcomes after TAVI and alternative risk parameters are lacking so far.

OBJECTIVE

We evaluated the CT-derived aortic valve calcification score as a predictor for outcome during and after TAVI.

METHODS

Transfemoral TAVI using the CoreValve device was performed in 68 patients, in whom the aortic valve calcium score was determined from preprocedural 64-sclice ECG gated CT-scans.

RESULTS

30-day MACE rate (death, stroke, MI) was 10.3%, 1-year mortality was 11.8%. Using linear regression analysis the aortic valve calcium score was the only significant predictor for 30-day MACE and for 1-year mortality and was also associated with the incidence and severity of post procedural aortic regurgitation (r=0.33, p<0.05). Patients withvalve calcium scores >750 had a significant lower 1-year survival rate compared to patients with scores <750 (58% vs. 98%, p<0.05). The aortic valve calcium score is also inversely associated with the absolute improvement of NYHA-class after TAVI (regression coefficient=-0.43, p<0.02).

CONCLUSION

The degree of aortic valve calcification is associated with post procedural aortic regurgitation, procedural complications, 1-year mortality and with the degree of functional improvement of patients who underwent TAVI using the CoreValve device. Due to the fact that the aortic valve calcium score can be determined from CT-datasets that are used for preprocedural planning, this parameter may be incorporated in the general work up and may be used for risk stratification and patient selection.

Comparison of magnetic resonance imaging of aortic valve stenosis and aortic root to multimodality imaging for selection of transcatheter aortic valve implantation candidates

The purpose of the present study was to compare the aortic valve area, aortic valve annulus, and aortic root dimensions measured using magnetic resonance imaging (MRI) with catheterization, transthoracic echocardiography (TTE), and transesophageal echocardiography (TEE). An optimal prosthesis--aortic root match is an essential goal when evaluating patients for transcatheter aortic valve implantation. Comparisons between MRI and the other imaging techniques are rare and need validation. In 24 consecutive, high-risk, symptomatic patients with severe aortic stenosis, aortic valve area was prospectively determined using MRI and direct planimetry using three-dimensional TTE and calculated by catheterization using the Gorlin equation and by Doppler echocardiography using the continuity equation. Aortic valve annulus and the aortic root dimensions were prospectively measured using MRI, 2-dimensional TTE, and invasive aortography. In addition, aortic valve annulus was measured using TEE. No differences in aortic valve area were found among MRI, Doppler echocardiography, and 3-dimensional TTE compared with catheterization (p = NS). Invasive angiography underestimated aortic valve annulus compared with MRI (p <0.001), TEE (p <0.001), and 2-dimensional TTE (p <0.001). Two-dimensional TTE tended to underestimate the aortic valve annulus diameters compared to TEE and MRI. In contrast to 2-dimensional TTE, 3 patients had aortic valve annulus beyond the transcatheter aortic valve implantation range using TEE and MRI. In conclusion, MRI planimetry, Doppler, and 3-dimensional TTE provided an accurate estimate of the aortic valve area compared to catheterization. MRI and TEE provided similar and essential assessment of the aortic valve annulus dimensions, especially at the limits of the transcatheter aortic valve implantation range.

Role of computed tomography imaging for transcatheter valvular repair/insertion

During the last decade, the development of transcatheter based therapies has provided feasible therapeutic options for patients with symptomatic severe valvular heart disease who are deemed inoperable. The promising results of many nonrandomized series and recent landmark trials have increased the number of percutaneous transcatheter valve procedures in high operative risk patients. Pre-procedural imaging of the anatomy of the aortic or mitral valve and their spatial relationships is crucial to select the most appropriate device or prosthesis and to plan the percutaneous procedure. Multidetector row computed tomography provides 3-dimensional volumetric data sets allowing unlimited plane reconstructions and plays an important role in pre-procedural screening and procedural planning. This review will describe the evolving role of multidetector row computed tomography in patient selection and strategy planning of transcatheter aortic and mitral valve procedures.