Curr Cardiol Rep (2013) 15:338 DOI 10.1007/s11886-012-0338-y

ECHOCARDIOGRAPHY (RM LANG, SECTION EDITOR)

Interventional Echocardiography in Structural Heart Disease Gila Perk & Itzhak Kronzon

Published online: 22 January 2013 # Springer Science+Business Media New York 2013

Abstract Over the past decade, catheter based treatments of an increasing variety of cardiac diseases have expanded dramatically. These advancements became available through new developments and improvements in available devices, as well as increasing expertise of operators. However, arguably it is the innovation and progress in imaging techniques, and in particular in echocardiography, that allowed for such a surge in available percutaneous procedures. In this paper, current echocardiographic techniques, imaging protocols and recommendations will be reviewed and clinical examples will be shown to illustrate the use and importance of echocardiographic imaging in catheter based procedures for structural heart disease. Keywords Echocardiography . Real time 3-dimensional echocardiography . Structural heart disease . Catheter-based interventions . Interventional echocardiography

Introduction Over the course of the last decade a significant increase in treatment options for a myriad of structural heart diseases has been seen [1••, 2••, 3••, 4–9]. Elderly patients or those

with significant comorbidities who are at increased risk for open heart procedures can now be offered treatments for otherwise untreatable conditions. Even younger, less sick patients can now choose to avoid open heart procedures and receive treatments that require shorter hospital admissions and a faster recovery period. The current availability of catheter-based treatments can be attributed to several important developments in available techniques, devices, operator expertise and imaging techniques. Successful completion of any catheter-based treatment for structural heart disease depends on a combination of multiple factors; accurate assessment of the nature of the defect to be treated, proper patient selection, appropriate procedure planning, precision and complication-avoidance during the procedure (with guidance, monitoring, verification of success and early identification of complications), and close patient follow up. Each of these steps heavily relies on accurate imaging. While many imaging techniques are utilized (e.g., CT scan, fluoroscopy, MRI), echocardiography is of utmost importance due to several characteristics that make it the ideal technique for this purpose. Echocardiography is portable and can be done at the procedure room, it allows for real-time imaging, and with utilization of 2D, 3D and Doppler techniques both anatomic and physiologic data can be obtained. Currently available procedures include: 1. Closure of intra-cardiac shunts including:

This article is part of the Topical Collection on Echocardiography G. Perk (*) Echocardiography Laboratory, Lenox Hill Hospital / North Shore LIJ Health System, Non Invasive Cardiology, 2E, 100 East 77th Street, New York, NY 10075, USA e-mail: [email protected]

a. Atrial septal defects (ASD) b. Persistent foramen ovale (PFO) c. Ventricular septal defects (VSD) (in particular post infarct VSDs) 2. Ventricular pseudoaneurysm closure 3. Treatment of valvular heart disease including:

I. Kronzon Cardiac Imaging Center, Lenox Hill Hospital / North Shore LIJ Health System, Non Invasive Cardiology, 2E, 100 East 77th Street, New York, NY 10075, USA e-mail: [email protected]

a. Edge-to-edge repair of mitral regurgitation (due to either degenerative valve disease or functional valve disease). b. Mitral balloon valvuloplasty for mitral stenosis

338, Page 2 of 9

c. Valve replacement for severe aortic stenosis in high risk patients 4. Treatment of a variety of prosthetic valve malfunctions including: a. Paravalvular leak closure b. Implantation of valve-in-valve for degenerative prosthetic valve disease 5. Obliteration of left atrial appendage 6. Pulmonary vein ablation for atrial fibrillation 7. Many congenital heart diseases can be treated with catheter-based procedures (including coiling of patent ductus arteriosus, stenting of aortic coarctation, opening of narrowed baffles, valvuloplasty for congenital aortic stenosis and pulmonic stenosis and more) however these will not be detailed in this review.

Echocardiographic Imaging Techniques Both transthoracic (TTE) and transesophageal (TEE) echocardiography can be used for pre-procedure and post procedure assessment. During a procedure, TEE is most commonly used as the image resolution is superior and it does not interfere with the procedure’s sterile field. All imaging modalities (2D, 3D, color and spectral Doppler) need to be used in conjunction in order to maximize the obtainable information. Occasionally intra-cardiac echocardiography (ICE) is utilized as well (see details below). Pre-Procedure Assessment Regardless of the specific pathology, several general considerations apply for all catheter-based intervention. Clearly a comprehensive echocardiographic examination needs to be performed, assessing for chamber sizes, left ventricular wall motion and ejection fraction, valvular function and presence of pericardial effusion. Presence of intracardiac clots (both atrial and left ventricular) should be specifically addressed as these may be an absolute contraindication to certain catheter based procedures, or may alter the approach for others. Assessment of aortic atherosclerosis is also of particular importance, especially if cannulation of the aorta is planned, as severe aortic atherosclerosis can significantly increase procedure risk and may require changing access approach or even re-consideration of patient selection. Intra-Procedure Guidance Similar to the pre-procedure screening, there are several general considerations that apply regardless of the procedure performed. Real time imaging techniques that can be used to guide and monitor a catheter based intervention include

Curr Cardiol Rep (2013) 15:338

fluoroscopy (with or without the use of CT overlay and co-registration of the CT images with the fluoroscopic ones), ICE, TTE, TEE. Traditionally, fluoroscopy has been always used in the catheterization laboratory. While important information can be derived from fluoroscopic imaging, several concerns limit its use for guidance of procedures; the spatial resolution is inadequate to delineate precisely catheter course and location, the radiation exposure (both to patient and operators) can be significant, and contrast use is often required. Echocardiography, a real-time, non-radiation, noncontrast, tomographic as well as 3-dimensional technique, is ideal for guidance during the procedure [10, 11]. Intra-cardiac echocardiography is performed via an ultrasound probe that is placed through a central venous access into the right atrium. The probe is inserted and manipulated by the interventionalist. The technique can potentially provide adequate images of near field structures [12]. The main advantages of the ICE are that it can be performed under conscious sedation, and it may be used in patients who have absolute contraindications to TEE (e.g., significant esophageal varices). ICE has already been shown to be helpful in a variety of catheter based procedures including trans-septal puncture guidance, closure of ASDs and VSDs, balloon valvuloplasty of mitral and aortic valve and more. There are several weaknesses to ICE; imaging planes are not as standardized as on TEE and significant variability in the images acquired exists, specific operator training in echocardiography is required, and an important disadvantage is that ICE catheters are single-use only, which increase the procedure cost significantly. The best spatial resolution and anatomic definition is generally obtained by TEE. The major disadvantage of it is that it often necessitates the use of general anesthesia; however the quality of the information obtained is unsurpassed, making TEE the primary technique for intraprocedural guidance. Use of intra-procedure TEE has already been shown to reduce fluoroscopy time, thus decreasing radiation exposure both to the patient and operator [13]. Catheter based interventions are usually performed in the catheterization laboratory or in a hybrid operating room, and require the expertise of a team from various clinical specialties. The echocardiographic examination starts with a quick assessment of the pathology being treated as well as verification of lack of any new contraindications (e.g., intracardiac clots, vegetations, etc.) Many procedures are performed via venous access and trans-septal puncture. TEE with use of RT3D imaging is of utmost importance during the transseptal puncture. The exact location of the puncture can be crucial for the success of the procedure; this site will determine the entry point of the guiding catheter into the left atrium, which in turn will affect all further catheter and device manipulations. The puncture site needs to be

Curr Cardiol Rep (2013) 15:338

Page 3 of 9, 338

Echocardiography is instrumental in assessing ASDs, PFOs and VSDs; it allows for both anatomic delineation of the

defect, as well as hemodynamic assessment (e.g., assessment of direction and magnitude of the shunt). Real time 3-dimensional (RT3D) TEE is the ideal technique to discern the anatomy of an ASD. Using any one of several imaging protocols available, secundum ASDs can be viewed en-face from both the right atrial and left atrial perspectives [15•, 16•]. The defect’s size, shape and complexity (e.g., existence of a fenestrated ASD) can be easily assessed and determine the type of device to be used in the procedure. Presence of adequate rim around the entire ASD should be confirmed in order to verify suitability for percutaneous closure attempt (Fig. 1). At present, only secundum ASDs are amenable for percutaneous treatment. Identification of the entry site of all four pulmonary veins into the left atrium is also of clinical importance, as anomalous pulmonary venous return is not treatable by a catheter based technique. During an ASD closure procedure, TEE with RT3D imaging enables following the entire course of the intracardiac catheters, and monitoring while the closure device is being placed (Fig. 1). The device can be seen in its entirety from both the left atrial and right atrial perspectives (Fig. 1). Accurate positioning of the device can be observed in real time, such that adjustments can be made if necessary prior to final deployment. Color Doppler imaging supplements the 3D and 2D imaging in confirming absence of any residual shunt. Occasionally more than one closure device is required to achieve adequate closure of the defect [17, 18]. Ventricular septal defects (VSD) can often be studied by RT3D TTE for pre-procedure assessment. Using image rotation and cropping, VSDs can often be visualized en-face, from both the left ventricular and right ventricular perspectives. This can help in planning the procedure and determining the appropriate device size for adequate closure. Post infarct VSDs were traditionally treated by surgical intervention. These surgeries tended to carry significant risk to the patient due to the timing (post infarct) and the need to suture into necrotic friable tissue. The recent advent of percutaneous treatment is an ideal alternative for these

Fig. 1 Secundum ASD as seen on RT3D TEE. Left panel shows preprocedure assessment. The entire ASD can be visualized and the presence of adequate rim around it can be confirmed. Center panel

shows intra-procedure image; the entire guiding catheter, including its tip can be visualized on one frame. Right panel shows the final result with a closure device in place, completely covering the entire defect

assessed both on the antero-posterior axis, as well as the superior-inferior axis. Using the 3D zoom mode or the full volume mode, the tenting site (where the trans-septal needle tip presses against the septum) can be visualized, and its location relative to the aortic valve as well as height above the mitral valve can be easily discerned. Another common access technique is via a trans-apical approach which involves direct, percutaneous puncture of the left ventricular apex [14]. When a trans-apical technique is utilized, the wires and guides can be visualized as they enter the left ventricle, confirming the proper performance of the puncture. A key advantage of RT3D TEE imaging during all catheter-based procedures is the ability to visualize all intracardiac catheters throughout their entire course in the heart, thus improving accuracy and safety of the procedure. Post-Procedure Follow Up Post procedure follow up is generally done by TTE although in certain cases TEE surveillance is required. In the hours and days following the procedure, echo is used to assess for immediate procedure-related complication (e.g., pericardial effusion, paravalvular leak etc.) For long term assessment, often the devices placed during the original procedure can be visualized on the follow up echocardiograms such that confirmation of their stable position is obtained. Even if the device(s) cannot be seen, echo can be used to verify correction of the underlying pathology; combing information obtained from 2D, color and spectral Doppler can usually provide the information required to ascertain the long term results of the procedure.

Specific Procedures Intra-Cardiac Shunts

338, Page 4 of 9

patients. Post-infarct VSDs tend to have a serpiginous track in the septum and identification of their location requires 2D, 3D and color Doppler imaging. RT3D (mainly in the 3D zoom mode) can allow for en-face visualization of the entry site to the defect, monitoring the course of the intracardiac catheters and imagining of the closure device from the left ventricular and right ventricular perspectives [19]. Ventricular Pseudoaneurysms Similar to post –infarct VSD, left ventricular pseudoaneurysm is a life-threatening complication of acute myocardial infarction, that until recently could only be treated surgically, with a very high risk involved. Echocardiography is essential for the diagnosis and demonstration of the communication with the left ventricle by color Doppler imaging. RT3D TEE further adds on the ability to image from multiple planes, such that often the opening of the neck of the pseudoaneurysm can be visualized en-face. Further assessment with other imaging modalities (e.g., CT scan) can be required, to discern the size and extent of the extra-cardiac portion of the pseudoaneurysm. Trans-catheter closure of post-infarct pseudoaneurysm is an attractive treatment alternative in these cases. With guidance by multi-modality imaging, the pseudoaneurysm can be entered percutaneously, the track connecting it to the left ventricle can be identified and a closure device can be placed to occlude the communication between the left ventricular and the pseudoaneurysm. Real time echocardiography during the procedure with color Doppler imaging can verify correct placement of the device and complete obliteration of the communication. Valvular Heart Disease Echocardiography has been the standard technique to assess presence and severity of valvular heart disease for quite a while [20]. With the recent advent of RT3D imaging, and in particular RT3D TEE, echocardiography has emerged as an essential technique for accurate and detailed anatomic, as well as physiologic assessment of valvular dysfunction [21••, 22–25]. Mitral Valve Disorders The mitral valve can be thoroughly evaluated by RT3D TEE. Utilizing the 3D zoom mode and the full volume mode, the mitral valve can be viewed from both the atrial perspective as well as the ventricular perspective. Every part of the valve can be evaluated; the annulus, leaflets, commissures, cords and papillary muscles. The en-face view of the mitral valve allows for precise identification of the different scallops of the leaflets, which in turn facilitates

Curr Cardiol Rep (2013) 15:338

accurately localizing any focal pathology (e.g., limited prolapse, perforation etc.). For ease of communication and uniform nomenclature, the mitral valve is generally presented in the “surgical view” where the aortic valve is on top, at the 12 o’clock position, the medial commissure is at 3 o’clock and the left atrial appendage and lateral commissure at 9 o’clock [26] (Fig. 2). When assessing mitral regurgitation, echocardiography is essential in quantifying the severity and extent of the leak. Quantification methods that are currently in use include: 1) Volumetric measurement of the regurgitant volume by measuring mitral inflow volume and forward stroke volume. 2) Estimation of the effective regurgitant orifice area by the Proximal Isovelocity Surface Area (PISA) method (which can also provide an assessment of the regurgitant volume). 3) Measuring the jet’s vena contract. 4) Estimation of the regurgitant jet area and percentage relative to the size of the left atrium. Supportive signs for the severity of mitral regurgitation can also be assessed like measuring chamber sizes, estimation of pulmonary artery pressure, left ventricular function and more. Exact delineation of the cause of the regurgitation can be obtained by echocardiography. Functional mitral regurgitation can be diagnosed when tethering of the leaflets is seen; the tenting area and coaptation depth and length can be measured, and the origin of the regurgitant jet can be found. When assessing degenerative valve disease (like myxomatous degeneration of the valve, prolapse of the leaflets or flail leaflet) the exact location of the prolapse can be identified (e.g., single scallop or multi-scallop), the flail gap can be measured, and the origin of the jet can be identified (Fig. 2). Several percutaneous techniques to treat mitral regurgitation have been developed. At present, the most commonly used one (which is still investigational) is the mitral clipping procedures. Echocardiography with RT3D imaging is the key imaging modality for guidance of percutaneous cliprepair of mitral regurgitation [27]. It involves insertion of a clip that grasps the tips of the two mitral leaflets and essentially creates an edge-to-edge repair of the valve. The procedure is done via a central venous access and a trans-septal puncture. Every step of the procedure is heavily dependent of echocardiographic guidance; the location of the transseptal puncture is extremely important to allow for steering and maneuverability of the guiding catheter and the clip. Once the clip is introduced into the left atrium, proper orientation of the clip is crucial; the clip arms need to be placed perpendicular to the mitral valve closure line. This is best evaluated using the 3D zoom mode and looking at the

Curr Cardiol Rep (2013) 15:338

Page 5 of 9, 338

Fig. 2 Mitral valve assessment on RT3D TEE. Top panels show a normal mitral valve as seen en face from the left atrial perspective during systole (left panel) and during diastole (right panel). The image has been rotated to display the valve in the surgical view. Bottom panels show a flail p2 segment of the posterior mitral leaflet with a torn cord pointing into the left atrium (same orientation as top panels). On the right lower panel – evidence of severe mitral regurgitation with a very large convergence hemisphere (PISA). LAA-left atrial appendage, AV-aortic valve, P1-3-scallops of the posterior mitral leaflet

mitral valve en face. Once the clip has been advanced into the left ventricle, grasping of the leaflets is attempted. Grasping is performed under real time echocardiographic visualization and monitoring, followed by confirmation of satisfactory leaflet insertion by imaging from multiple angles. Finally, once the clip arms are closed, color Doppler is used to assess if substantial reduction in mitral regurgitation has been achieved. If the result after one clip is suboptimal, in many cases a second clip can be implanted. Echocardiography is also central to the diagnosis of mitral stenosis. Doppler echocardiography is utilized to measure the mean pressure gradient across the valve, as well as the pressure half time which is used to calculate the mitral valve area. PISA method can be used to calculate the mitral valve area. Direct planimetry of the mitral valve area is considered the most accurate method to define severity of mitral stenosis. 3D guided planimetry, done by post processing of a 3D image, is considered the technique of choice for measuring mitral valve area. With this technique, measuring the mitral valve area at the smallest orifice (at the tips of the leaflets) can be guaranteed and the measurement plane can be precisely adjusted according to the valve orifice. 2D and 3D imaging are required to define the etiology of mitral stenosis. Commissural fusion, the hallmark of rheumatic mitral stenosis, can be easily identified on echocardiography. Suitability for percutaneous balloon valvuloplasty can be assessed using the Wilkins valve score, which takes into consideration leaflet mobility, thickening, calcification and subvalvular thickening extent. Presence of coexisting significant mitral regurgitation is also assessed as this

precludes a percutaneous treatment option. Degenerative mitral stenosis from extensive mitral annular calcification can be identified and quantified as well. During balloon valvuloplasty procedure TEE is used to guide the location of the trans-septal puncture and monitor the position of the balloon before and during inflation. Immediate assessment of the degree of residual mitral stenosis and the commissural tear achieved can be obtained, as well as evaluation for any possible complications like leaflet tear or significant mitral regurgitation [28]. Aortic Valve Disorders Currently, the technique of choice to assess for presence and severity of aortic stenosis is echocardiography. Anatomic and physiologic assessment of the valve, as well as evaluation of the proximal ascending aorta is readily performed by echo. Congenital abnormalities of the aortic valve (like bicuspid, or more rarely unicuspid or quadricuspid aortic valve) can be diagnosed by 2D and 3D TTE or TEE. Often planimetry of the valve area can be performed for direct measurement of the aortic valve area although the most commonly used technique to calculate aortic valve area is utilizing the continuity equation. Spectral Doppler is used to measure the peak and mean gradient across the aortic valve. When assessing suitability for percutaneous aortic valve replacement, aside from confirming the diagnosis of severe aortic stenosis, echocardiography is required to verify the anatomic fitness for a percutaneous valve. Accurate measurements of the aortic annulus, aortic root and sinus of

338, Page 6 of 9

Valsalva height are necessary in order to decide on the appropriate prosthetic valve size. While echo provides acceptable measurements of these parameters, CT scan images with post-processing and direct planimetry of these areas may provide superior accuracy for these measurements [29–31]. More recently, 3D guided direct planimetry of these areas by post-processing of RT3D TEE images has been shown to have excellent correlation with CT derived numbers. This may be of significant clinical importance, especially in patients who cannot undergo CT scanning (e.g., patients with insufficiency) [32]. Evaluation of the aortic arch for presence and severity of atherosclerotic plaque is of particular importance in these cases. If a trans-femoral retrograde approach is considered, severe arch atherosclerosis may be a contraindication for the procedure and an alternative approach (e.g., trans-apical) may need to be chosen. During the procedure TEE can be used to help in guidance of the immediate pre-implant aortic balloon valvuloplasty as well as verification of proper valve positioning and assessment for presence of immediate complications like pericardial effusion or paravalvular aortic regurgitation [33, 34]. Prosthetic Valve Disorders Echocardiography is ideal for evaluation of prosthetic valve function. In order to reach the most accurate conclusion Fig. 3 Paravalvular leak. Top left – Prosthetic mitral valve as shown from the left atrial perspective with a large segment of dehiscence at around the 9 o’clock position. Top right – intra-procedure image showing the wire passing through the valve leaflets. The wire was pulled back and repositioned. Bottom left – Wire passing through the paravalvular leak site. Note how the 3D image allows for clear delineation of the path of the wire. Bottom right – 2 closure devices being pulled down to occlude the paravalvular leak site. Pros-prosthetic valve, PVLparavalvular leak site

Curr Cardiol Rep (2013) 15:338

regarding prosthetic valve function, information should be obtained by TTE, TEE and RT3D echocardiography. Imaging from the two approaches (TTE and TEE) can generally overcome limitations related to acoustic shadowing, and RT3D TEE allows for detailed anatomic and functional evaluation of the prosthetic valve [35, 36]. Color and spectral Doppler are utilized to assess for presence of prosthetic valvular regurgitation. If valve regurgitation is identified, differentiation between transvalvular and paravalvular regurgitation can be achieved. The mitral valve is very readily imaged by RT3D TEE; if paravalvular leak (PVL) is found the exact number of PVL sites can be discerned, as well as the exact location, size, and shape of each (Fig. 3). This information is crucial in planning the procedure - for example which access approach to choose and which closure devices to use. The aortic valve is somewhat less optimally imaged on RT3D TEE for several reasons – the aortic valve is a more anterior structure, making it further away from the probe on TEE imaging, and in many imaging planes the valve is oblique to the ultrasound beam. However, the anterior location of the aortic valve makes it more easily imaged by TTE such that the combined information obtained from all the echo modalities is usually sufficient to make accurate assessment of prosthetic valve function and discerning the origin of any prosthetic valve leak. During a catheter-based PVL closure procedure, echocardiography, especially with RT3D imaging, is essential to

Curr Cardiol Rep (2013) 15:338

verify the correct location of the guiding catheter. Only RT3D TEE imaging allows to accurately discern whether the guiding catheter is passed through the PVL site vs. through the prosthetic valve leaflets (Fig. 3). Once proper positioning has been achieved, a closure device can be placed at the PVL site. The results can be immediately assessed, before final deployment of the closure device, such that if inadequate occlusion of the PVL is seen the device can be repositioned as necessary. In cases of degenerative prosthetic valve disorder, echocardiography is fundamental in making the diagnosis, defining the severity and assessing progression over time as well as response to medical treatment. Mean gradient across both the mitral valve and aortic valve are accurately measured by spectral Doppler, in most cases on TTE. If prosthetic stenosis is suspected, anatomic confirmation by TEE with RT3D imaging is critical in order to better delineate the nature of the pathology. If a valve-in-valve treatment is considered it is imperative to rule out any clot or vegetation or other masses that might be causing the increased gradient across the valve. Echo is also important in differentiating between prosthetic valve stenosis and patient-valve mismatch, which may require a different treatment. An exciting option for treatment of degenerative bioprosthetic valve disease is implantation of a new valve in the old prosthesis; the “valve-in-valve” procedure. When a valve-in-valve procedure is performed, echocardiographic guidance is required to verify accurate positioning of the new valve in the prior bio-prosthetic valve. Once the new valve is deployed, immediate assessment of its function, including measurement of the gradient across it and assessing for any leak can be made. Left Atrial Obliteration Atrial fibrillation is the most common arrhythmia encountered in adult population. One of the main risks associated with it is embolic complications due to intra-cardiac clot formation. Currently, the best available management option to reduce this risk is anticoagulation treatment. However there are many patients who cannot take anticoagulation medications due to coexisting contraindications. As more than 90 % of intra-atrial clots that occur in association with atrial fibrillation are found in the left atrial appendage (LAA), obliteration of the LAA has been suggested as an alternative treatment option. Several surgical techniques have been used for this purpose and more recently a percutaneous option has been developed. Prior to implanting any obliteration device in the LAA anatomic suitability, as well as lack of contraindications need to be assessed. TEE is the technique of choice for pre-procedure assessment. The size of the left atrial appendage opening needs to be accurately

Page 7 of 9, 338

measured; utilizing TEE with multiplane imaging, the diameter of the opening can be measured in all angles. RT3D TEE with post-processing allows for direct planimetry of the LAA opening, such that no geometrical assumptions regarding the shape of the opening need to be made. TEE is also the optimal technique to confirm absence of left atrial and LAA clot prior to the procedure, which would be an absolute contraindication to placement of any obliteration device. During the procedure, TEE and RT3D TEE are used to visualize all catheters throughout their intra-cardiac course and confirm proper positioning of the closure device at the opening of the LAA. Prior to final deployment, proper seal of the LAA opening can be confirmed both by an en-face view obtained by RT3D imaging, as well as color Doppler imaging to verify no leak around the device. If the placement is deemed suboptimal, adjustment and repositioning can be done until proper seal is obtained [37, 38]. Pulmonary Vein Ablation Pulmonary vein ablation is a new treatment option for atrial fibrillation that has been developed over recent years. Commonly this is done under fluoroscopic and electrophysiological mapping guidance; however several centers have started utilizing RT3D TEE guidance for these procedures [39]. Pre-procedure screening is important to rule out presence of left atrial or LAA clot which would be an absolute contraindication for the procedure, as well as assessment for any co-existing cardiac or valvular disorder that may make the procedure less likely to succeed (e.g., mitral stenosis). Utilizing RT3D during the procedure can help delineate the exact location of the ablation catheter and its relation to other intra-atrial structures (e.g., the LAA, mitral valve). Use of RT3D TEE guidance has been shown to significantly reduce fluoroscopy time thus making the procedure safer both for the patient and the operator.

Conclusion Trans-catheter treatment of a myriad of structural heart disease has dramatically advanced over the past decade. This expansion was tied hand in hand with improvement in imaging techniques, and especially the development of real time 3-dimensional transesophageal echocardiography. These procedures require real-time, precise delineation of the cardiac anatomy with continuous visualization and monitoring of catheter location. The only available technique that allows for such detailed resolution in real-time is RT3D TEE, which in essential for the successful performance of these procedures.

338, Page 8 of 9 Disclosure Conflicts of interest: G. Perk: none; I. Kronzon: has received honoraria and travel/accommodations expenses covered or reimbursed from Phillips.

References Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance

Curr Cardiol Rep (2013) 15:338

16.

17.

18.

19. 1. •• Kodali SK, Williams MR, Smith CR, et al. Two-year outcomes after transcatheter or surgical aortic-valve replacement. N Engl J Med. 2012;366(18):1686–95. Randomized trials showing outcome data pertaining to new, catheter-based procedures that are currently in use. 2. •• Makkar RR, Fontana GP, Jilaihawi H, et al. Transcatheter aorticvalve replacement for inoperable severe aortic stenosis. N Engl J Med. 2012;366(18):1696–704. Randomized trials showing outcome data pertaining to new, catheter-based procedures that are currently in use. 3. •• Feldman T, Foster E, Glower DD, et al. Percutaneous repair or surgery for mitral regurgitation. N Engl J Med. 2011;364 (15):1395–406. Randomized trials showing outcome data pertaining to new, catheter-based procedures that are currently in use. 4. Butera G, Carminati M, Chessa M, et al. Percutaneous versus surgical closure of secundum atrial septal defect: comparison of early results and complications. Am Heart J. 2006;151(1):228–34. 5. Mookadam F, Raslan SF, Jiamsripong P, Jalal U, Murad MH. Percutaneous closure of mitral paravalvular leaks: a systematic review and meta-analysis. J Heart Valve Dis. 2012;21(2):208–17. 6. Ruiz CE, Jelnin V, Kronzon I, et al. Clinical outcomes in patients undergoing percutaneous closure of periprosthetic paravalvular leaks. J Am Coll Cardiol. 2011;58(21):2210–7. 7. Gangireddy SR, Halperin JL, Fuster V, Reddy VY. Percutaneous left atrial appendage closure for stroke prevention in patients with atrial fibrillation: an assessment of net clinical benefit. Eur Heart J. 2012. doi:10.1093/eurheartj/ehs292. 8. Piccini JP, Sinner MF, Greiner MA, et al. Outcomes of Medicare beneficiaries undergoing catheter ablation for atrial fibrillation. Circulation. 2012. doi:10.1161/CIRCULATIONAHA.112.109330. 9. Khan MN, Jaïs P, Cummings J, et al. Pulmonary-vein isolation for atrial fibrillation in patients with heart failure. N Engl J Med. 2008;359(17):1778–85. 10. Perk G, Lang RM, Garcia-Fernandez MA, et al. Use of real time threedimensional transesophageal echocardiography in intracardiac catheter based interventions. J Am Soc Echocardiogr. 2009;22(8):865–82. 11. Balzer J, Kelm M, Kühl HP. Real time three dimensional transoesophageal echocardiography for guidance of non-coronary interventions in the catheter laboratory. Eur J Echocardiogr. 2009;10(3):341–9. 12. Hijazi ZM, Shivkumar K, Sahn DJ. Intracardiac echocardiography during interventional and electrophysiological cardiac catheterization. Circulation. 2009;119(4):587–96. 13. Schubert S, Kainz S, Peters B, Berger F, Ewert P. Interventional closure of atrial septal defects without fluoroscopy in adult and pediatricpatients. Clin Res Cardiol. 2012;101(9):691–700. 14. Jelnin V, Dudiy Y, Einhorn BN, et al. Clinical experience with percutaneous left ventricular transapical access for interventions in structural heart defects a safe access and secure exit. JACC Cardiovasc Interv. 2011;4(8):868–74. 15. • Saric M, Perk G, Purgess JR, Kronzon I. Imaging atrial septal defects by real-time three-dimensional transesophageal echocardiography: step-by-step approach. J Am Soc Echocardiogr. 2010;23

20.

21.

22.

23. 24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

(11):1128–35. Describing new imaging protocols or setting standards for 3-dimensional imaging. • Faletra FF, Nucifora G, Ho SY. Imaging the atrial septum using real-time three-dimensional transesophagealechocardiography: technical tips, normal anatomy, and its role in transseptal puncture. J Am Soc Echocardiogr. 2011;24(6):593–9. Describing new imaging protocols or setting standards for 3-dimensional imaging. Lodato JA, Cao QL, Weinert L, et al. Feasibility of real-time threedimensional transesophageal echocardiography for guidance of percutaneous atrial septal defect closure. Eur J Echocardiogr. 2009;10(4):543–8. Faletra FF, Nucifora G, Ho SY. Real-time 3-dimensional transesophageal echocardiography of the atrioventricular septal defect. Circ Cardiovasc Imaging. 2011;4(3):e7–9. Halpern DG, Perk G, Ruiz C, Marino N, Kronzon I. Percutaneous closure of a post-myocardial infarction ventricular septal defect guided by real-time three-dimensional echocardiography. Eur J Echocardiogr. 2009;10(4):569–71. Flachskampf FA, Badano L, Daniel WG, et al. Recommendations for transoesophageal echocardiography: update 2010. Eur J Echocardiogr. 2010;11(7):557–76. •• Zamorano JL, Badano LP, Bruce C. EAE/ASE recommendations for the use of echocardiography in new transcatheter interventions for valvular heart disease. J Am Soc Echocardiogr. 2011;24(9):937–65. Randomized trials showing outcome data pertaining to new, catheter-based procedures that are currently in use. Cavalcante JL, Rodriguez LL, Kapadia S, Tuzcu EM, Stewart WJ. Role of echocardiography in percutaneous mitral valve interventions. JACC Cardiovasc Imaging. 2012;5(7):733–46. Naqvi TZ. Echocardiography in percutaneous valve therapy. JACC Cardiovasc Imaging. 2009;2(10):1226–37. Sugeng L, Shernan SK, Weinert L, et al. Real time threedimensional transesophageal echocardiography in valve disease: comparison with surgical findings and evaluation of prosthetic valves. J Am Soc Echocardiogr. 2008;21(12):1347–54. Lang RM, Tsang W, Weinert L, Mor-Avi V, Chandra S. Valvular heart disease. The value of 3-dimensional echocardiography. J Am Coll Cardiol. 2011;58(19):1933–44. Lang RM, Badano LP, Tsang W, et al. EAE/ASE recommendations for image acquisition and display using three-dimensional echocardiography. J Am Soc Echocardiogr. 2012;25(1):3–46. Biner S, Perk G, Kar S, et al. Utility of combined two-dimensional and three-dimensional transesophageal imaging for catheter-based mitral valve clip repair of mitral regurgitation. J Am Soc Echocardiogr. 2011;24(6):611–7. Park SH, Kim MA, Hyon MS. The advantages of on-line transesophageal echocardiography guide during percutaneous balloon mitral valvuloplasty. J Am SocEchocardiogr. 2000;13(1):26–34. Poh KK, Levine RA, Solis J, Shen L, et al. Assessing aortic valve area in aortic stenosis by continuity equation: a novel approach using real-time three-dimensional echocardiography. Eur Heart J. 2008;29(20):2526–35. O'Brien B, Schoenhagen P, Kapadia SR, et al. Integration of 3D imaging data in the assessment of aortic stenosis: impact on classification of disease severity. Circ Cardiovasc Imaging. 2011;4(5):566–73. Doddamani S, Bello R, Friedman MA, et al. Demonstration of left ventricular outflow tract eccentricity by real time 3D echocardiography: implications for the determination of aortic valve area. Echocardiography. 2007;24(8):860–6. Saitoh T, Shiota M, Izumo M, et al. Comparison of left ventricular outflow geometry and aortic valve area in patients with aortic stenosis by 2-dimensional versus 3-dimensional echocardiography. Am J Cardiol. 2012;109(11):1626–31. Moss RR, Ivens E, Pasupati S, et al. Role of echocardiography in percutaneous aortic valve implantation. JACC Cardiovasc Imaging. 2008;1(1):15–24.

Curr Cardiol Rep (2013) 15:338 34. Berry C, Oukerraj L, Asgar A, et al. Role of transesophageal echocardiography in percutaneous aortic valve replacement with the CoreValve Revalving system. Echocardiography. 2008;25 (8):840–8. 35. Tsang W, Weinert L, Kronzon I, Lang RM. Three-dimensional echocardiography in the assessment of prosthetic valves. Rev Esp Cardiol. 2011;64(1):1–7. 36. Kronzon I, Sugeng L, Perk G, et al. Real-time 3-dimensioanl transesophageal echocardiography in the evaluation of post operative mitral annuloplasty ring and prosthetic valve dehiscence. J Am Coll Cardiol. 2009;53(17):1543–7.

Page 9 of 9, 338 37. Perk G, Biner S, Kronzon I. Catheter-based left atrial appendage occlusion procedure: role of echocardiography. Eur Heart J Cardiovasc Imaging. 2012;13(2):132–8. 38. Brinkman V, Kalbfleisch S, Auseon A, Pu M. Real time threedimensional transesophageal echocardiography-guided placement of left atrial appendage occlusion device. Echocardiography. 2009;26(7):855–8. 39. Mackensen GB, Hegland D, Rivera D, Adams DB, Bahnson TD. Real-time 3-dimensional transesophageal echocardiography during left atrial radiofrequencycatheter ablation for atrial fibrillation. Circ Cardiovasc Imaging. 2008;1(1):85–6.