Echocardiography in Percutaneous Valve Therapy

Use of Computed Tomography to Guide Mitral Interventions

With increasing utilization of cardiac computed tomographic angiography (CTA) and widespread adoption of fusion imaging technology allowing the merger of pre-procedural CTA with fluoroscopy, the ability of CTA to guide structural heart interventions has evolved significantly. It has opened new possibilities in mitral valve (MV) interventions with improved pre-procedural planning and intra-procedural guidance. Given the lack of fluoroscopic landmarks of the mitral apparatus and continued growth of native MV device technologies, the value of CTA will continue to develop. The goal of this chapter is to detail the role of CTA in MV imaging and support for transcatheter therapies.

Incremental value of 3-D transesophageal echocardiographic imaging of the mitral valve

Transesophageal echocardiography provides excellent visualization of the posteriorly located mitral valve. Over the last decade, 3-dimensional transesophageal echocardiography (3D TEE) has emerged as an exciting imaging modality, particularly of the mitral valve. The current generation matrix array technology allows the operator to perform 2D and 3D imaging with a single transducer. 3D TEE affords the unique ability to view the mitral valve and its surrounding structures "en face" in real time (RT), and provide contextual anatomical guidance during surgical and transcatheter interventions. Additionally, offline quantification has made significant contributions to our mechanistic understanding of the normal and diseased mitral valve, and alterations induced by therapeutic intervention such as surgical repair. This review will address recent advances in the incremental role of 3D TEE in mitral valve imaging.

Aortic intracardiac echocardiography-guided septal puncture during mitral valvuloplasty

AIMS

Transoesophageal echocardiography (TEE) and venous intracardiac echocardiography (ICE) are traditionally used to visualize the interatrial septum (IAS) and the tenting effect of the fossa ovalis in patients undergoing percutaneous balloon mitral valvuloplasty (PBMV). The aim of the present study was to assess the comparative efficacy and safety of arterial (intra-aortic) ICE and venous ICE, compared with TEE (traditional approach), in the patients undergoing PBMV.

METHODS AND RESULTS

TEE, aortic ICE, and venous ICE were consecutively performed in 50 patients (40 ± 9 years, 86% female). The images of intracardiac structures were obtained from both aortic and right atrial loci. The IAS was visualized using TEE, aortic ICE, and venous ICE. The mean mitral valve area was 1.14 ± 0.2 cm(2), and the mean left atrial volume index was 57.5 ± 12 mL/m(2). The mean size of the visualized septal length was 48 ± 5 mm by TEE, 51 ± 5 mm by aortic ICE, and 33 ± 6 mm by venous ICE. The Bland-Altman test indicated that the 95% limits of agreement for the measurement of septal diameter ranged from -11.0 to +5.9 mm (mean -2.5 mm) between TEE and aortic ICE, -2.8 to +33.5 mm (mean +15.3 mm) between TEE and venous ICE, and -36.6 to +0.8 mm (mean -17.9 mm) between venous and aortic ICE. Standard venous ICE generally tended to yield smaller values compared with TEE and aortic ICE for the measurement of septal length. Furthermore, the view of fossa ovalis and 'tenting effect' was optimal in 11 patients on venous ICE; however, the fossa ovalis and tip of the needle were well visualized in all patients on aortic ICE (P < 0.001). There were no major complications with the use of aortic ICE.

CONCLUSION

Aortic ICE is a superior alternative to venous ICE and facilitates trans-septal puncture in patients with mitral stenosis.

Multimodality imaging throughout transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is a novel, less-invasive technique used to treat selected patients with severe aortic valve stenosis with a high surgical risk. Noninvasive imaging before, during and after the procedure is of the utmost importance in this minimally invasive procedure. Screening of the patient and sizing of the aortic root by echocardiography and multislice computed tomography is of great importance to ensure success of the TAVI procedure. Echocardiography and fluoroscopy are essential during the procedure. During follow-up of the patients, echocardiography is important to evaluate the prosthesis function, durability and integrity. Additionally, multislice computed tomography and MRI might be helpful in the follow-up of selected cases. This article outlines the evolving role of multimodality imaging throughout TAVI in patients with severe aortic valve stenosis. It describes, in a stepwise approach, how multimodality imaging by echocardiography, angiography, multislice computed tomography and MRI enhances the TAVI procedure.

Advances in 3D echocardiography for mitral valve

The advent of real-time (RT) 3D transesophageal echocardiography (TEE) in 2007 has enhanced our understanding of the location and extent of the pathology of the native, as well as prosthetic, mitral valve (MV), particularly for MV prolapse and the anatomy of perivalvular dehiscence with prosthetic MV. MV quantification programs provide precise assessment of many quantitative MV parameters allowing 3D echocardiography to determine and quantify the geometry of mitral apparatus, including mitral annulus and periannular region, leaflet volume and anatomy, tethering distances, and tenting volumes. The detailed, accurate and optimal RT spatial visualization of the MV with 3D TEE gives greater confidence to the echocardiographer, interventionalist and the surgeon alike, facilitating medical and surgical treatment decisions. This article highlights recent advances in RT 3D TEE and transthoracic echocardiography echocardiographic imaging of the MV.

Usefulness of TEE as the primary imaging technique to guide transcatheter transapical aortic valve implantation

OBJECTIVES

The aim of this study was to: 1) determine the usefulness of transesophageal echocardiography (TEE) as the primary technique to guide transapical (TA) transcatheter aortic valve implantation (TAVI); and 2) to compare TEE with angiography as the primary imaging modality for TA-TAVI guidance.

BACKGROUND

TEE has been routinely used as an adjunct to angiography during TA-TAVI procedures, but very few data exist on the use of TEE as the primary imaging technique guiding TA-TAVI.

METHODS

One hundred consecutive high-risk patients (mean age 79 ± 9 years, mean logistic EuroSCORE: 25.8 ± 17.6%) who underwent TA-TAVI in our center were included. The Edwards valve was used in all cases, and all procedures were performed in an operating room without hybrid facilities. The TA-TAVI was primarily guided by angiography in the first 25 patients (A-TAVI group) and by TEE in the last 75 patients (TEE-TAVI group). Procedural, 30-day, and follow-up results were evaluated.

RESULTS

No differences were observed between groups at baseline except for a higher (p = 0.001) prevalence of moderate or severe mitral regurgitation in the TEE-TAVI group. The procedure was successful in 97.3% and 100% of the patients in the TEE-TAVI and A-TAVI groups, respectively (p = 1.0), and a lower contrast volume was used in the TEE-TAVI group (12 [5 to 20] ml vs. 40 [20 to 50] ml, p < 0.0001). There were no differences between groups in the occurrence of valve malposition needing a second valve (TEE-TAVI: 5.3%; A-TAVI: 4%; p = 1.0) or valve embolization (TEE-TAVI: 1.3%; A-TAVI: 4%; p = 0.44). The results regarding post-procedural valve hemodynamic status and aortic regurgitation were similar between groups. The survival rates at 30-day and 1-year follow-up were 87% and 75% in the TEE-group and 88% and 84% in the A-TAVI group, respectively (log-rank = 0.49).

CONCLUSIONS

TEE-TAVI was associated with similar acute and midterm results as A-TAVI and significantly reduced contrast media use during the procedures. These results suggest the feasibility and safety of performing TA-TAVI procedures in an operating room without hybrid facilities, but larger studies are needed to confirm these findings.

Accuracy of 3-dimensional transoesophageal echocardiography in assessment of prosthetic mitral valve dehiscence with comparison to anatomical specimens

The evolution of echocardiography from 2-Dimensional Transthoracic Echo through to real time 3-Dimensional Transoesophageal Echo has enabled more accurate visualisation and quantification of valvular disorders especially prosthetic mitral valve paravalvular regurgitation. However, validation of accuracy is rarely confirmed by surgical or post-mortem specimens. We present a case directly comparing different echocardiographic modality images to post mortem specimens in a patient with prosthetic mitral valve paravalvular regurgitation.