Initial clinical experience with intracardiac echocardiography in guiding balloon mitral valvuloplasty: technique, safety, utility, and limitations

Intracardiac echocardiography Chinese expert consensus

In recent years, percutaneous catheter interventions have continuously evolved, becoming an essential strategy for interventional diagnosis and treatment of many structural heart diseases and arrhythmias. Along with the increasing complexity of cardiac interventions comes ever more complex demands for intraoperative imaging. Intracardiac echocardiography (ICE) is well-suited for these requirements with real-time imaging, real-time monitoring for intraoperative complications, and a well-tolerated procedure. As a result, ICE is increasingly used many types of cardiac interventions. Given the lack of relevant guidelines at home and abroad and to promote and standardize the clinical applications of ICE, the members of this panel extensively evaluated relevant research findings, and they developed this consensus document after discussions and correlation with front-line clinical work experience, aiming to provide guidance for clinicians and to further improve interventional cardiovascular diagnosis and treatment procedures.

The Role of Intracardiac Echocardiography in Percutaneous Tricuspid Intervention: A New ICE Age

The prevalence of severe tricuspid regurgitation in older patients is high, and the clinical relevance is perceived more and more in recent years. Many of these patients are not suitable for surgery because of their age and comorbidities. Therefore, a variety of percutaneous interventions have been developed to address this unmet need. Procedural success strongly depends on adequate imaging during the intervention. Although transesophageal echocardiography is the standard of care, imaging may be limited due to anatomic factors and adverse acoustic shadowing. In this review, we discuss the current and future role of intracardiac echocardiography in tricuspid valve interventions.

Use of Intracardiac Echocardiography in Interventional Cardiology: Working With the Anatomy Rather Than Fighting It

The indications for catheter-based structural and electrophysiological procedures have recently expanded to more complex scenarios, in which an accurate definition of the variable individual cardiac anatomy is key to obtain optimal results. Intracardiac echocardiography (ICE) is a unique imaging modality able to provide high-resolution real-time visualization of cardiac structures, continuous monitoring of catheter location within the heart, and early recognition of procedural complications, such as pericardial effusion or thrombus formation. Additional benefits are excellent patient tolerance, reduction of fluoroscopy time, and lack of need for general anesthesia or a second operator. For these reasons, ICE has largely replaced transesophageal echocardiography as ideal imaging modality for guiding certain procedures, such as atrial septal defect closure and catheter ablation of cardiac arrhythmias, and has an emerging role in others, including mitral valvuloplasty, transcatheter aortic valve replacement, and left atrial appendage closure. In electrophysiology procedures, ICE allows integration of real-time images with electroanatomic maps; it has a role in assessment of arrhythmogenic substrate, and it is particularly useful for mapping structures that are not visualized by fluoroscopy, such as the interatrial or interventricular septum, papillary muscles, and intracavitary muscular ridges. Most recently, a three-dimensional (3D) volumetric ICE system has also been developed, with potential for greater anatomic information and a promising role in structural interventions. In this state-of-the-art review, we provide guidance on how to conduct a comprehensive ICE survey and summarize the main applications of ICE in a variety of structural and electrophysiology procedures.

Intracardiac Echocardiography for Structural Heart and Electrophysiological Interventions

PURPOSE OF REVIEW

With an increasing number of interventional procedures performed for structural heart disease and cardiac arrhythmias each year, echocardiographic guidance is necessary for safe and efficient results. The purpose of this review article is to overview the principles of intracardiac echocardiography (ICE) and describes the peri-interventional role of ICE in a variety of structural heart disease and electrophysiological interventions.

RECENT FINDINGS

Both transthoracic (TTE) and transesophageal echocardiography have limitations. ICE provides the advantage of imaging from within the heart, providing shorter image distances and higher resolution. ICE may be performed without sedation and avoids esophageal intubation as with transesophageal echocardiography (TEE). Limitations of ICE include the need for additional venous access with possibility of vascular complications, potentially higher costs, and a learning curve for new operators. Data supports the use of ICE in guiding device closure of interatrial shunts, transseptal puncture, and electrophysiologic procedures. This paper reviews the more recent reports that ICE may be used for primary guidance or as a supplement to TEE in patients undergoing left atrial appendage (LAA) closure, interatrial shunt closure, transaortic valve implantation (TAVI), percutaneous mitral valve repair (PMVR), paravalvular leak (PVL) closure, aortic interventions, transcatheter pulmonary valve replacement (tPVR), ventricular septal defect (VSD), and patent ductus arteriosus (PDA) closure. ICE imaging technology will continue to expand and help improve structural heart and electrophysiology interventions.

The Utility of Intracardiac Echocardiography Following Melody™ Transcatheter Pulmonary Valve Implantation

The aim of this study was to determine the utility of intracardiac echocardiography (ICE) in assessing Melody™ transcatheter pulmonary valve (TPV) function immediately following valve implantation. ICE is used increasingly in percutaneous cardiac interventions. At our center, ICE is routinely utilized to evaluate valve function following Melody TPV implantation, but the utility of this practice remains unclear. A retrospective review of all Melody valves placed in the right ventricular outflow tract from April 2010 to September 2013 was performed. The clinical utility of ICE was described, along with the relationship between ICE data and traditional hemodynamic/angiographic data. ICE was performed in 54 cases and provided excellent Melody TPV visualization with no complications. ICE did not change clinical management but did provide supplemental information in two cases. In one case, angiography showed severe catheter-related Melody insufficiency. Subsequent ICE confirmed no insufficiency and prevented the need for additional angiography. In the second case, ICE allowed characterization of the mechanism of a residual gradient. ICE did not detect any clinically significant paravalvar leaks or valvar insufficiency not seen by angiography. The peak catheterization gradient was more closely approximated by the mean ICE gradient (median difference -7.4 % between measurements) than by the peak ICE gradient (median difference 58.3 %; p < 0.0001). ICE provides excellent and safe visualization following Melody TPV implantation but did not provide new clinical information impacting management in this series. Selective use of ICE in cases with more than expected valve insufficiency or larger than expected residual gradients may streamline use while maintaining optimal clinical outcomes.

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.

Intracardiac echocardiography: clinical utility and application

Intracardiac echocardiography (ICE) broadens the spectrum of available echocardiographic techniques and provides the operator direct visualization of cardiac structures in real time. ICE has clear advantages over fluoroscopy, transthoracic echocardiography, and transesophageal echocardiography as the imaging modality of choice in the cardiac catheterization and electrophysiological laboratories. With the development of steerable phased array catheters with low frequency and Doppler qualities, there is marked improvement in visualization of left-sided structures from the right heart. Appropriate utilization of ICE is likely to maximize safety and efficacy of complex interventional procedures and may improve patient outcomes. Future advances in ICE imaging will further improve the ease of device guidance and, in combination with new imaging modalities, could dramatically improve other applications of echocardiography which may result in improved patient outcomes. This review describes the technical evolution of ICE, the use of ICE in guiding percutaneous interventional procedures and possible future applications of ICE in the ever-growing field of interventional cardiology.

Comparisons of mechanical versus phase-array intracardiac echocardiography-assisted transseptal puncture in patients with dilated left atrium undergoing percutaneous transvenous mitral commissurotomy

BACKGROUND

Percutaneous transvenous mitral commissurotomy (PTMC) is an effective treatment for mitral stenosis, but transseptal puncture carries a certain risk of complications. Our previous report has shown the effectiveness of phase-array intracardiac echocardiography (ICE)-guided transseptal puncture in patients with dilated left atrium undergoing PTMC. However, there are few reports comparing the new-generation mechanical versus phase-array ICE-guided transseptal puncture in PTMC.

METHODS

Between March 2007 and March 2008, 6 consecutive patients with symptomatic mitral stenosis with dilated left atrium (range, 4.1-6.1 cm) underwent transseptal puncture by mechanical ICE guidance in PTMC by the same experienced operator. The procedural, echocardiographic and clinical results were retrospectively retrieved and analyzed. In addition, phase-array ICE-guided transseptal cases (n = 7), which included consecutive cases from May to December 2008, were compared.

RESULTS

All 6 patients could have fossa ovalis visualized by ICE, and none of them had false transseptal puncture. Mechanical ICE provided a panoramic wider view of the interatrium septum, and offered better knowledge of the needle's geographic contact to the fossa ovalis than did the phase-array system. The fluoroscopic time of PTMC in the mechanical ICE-guided group (37 ± 9 minutes, n = 6) was similar (p = 0.465) to that of phase-array guidance (31 ± 15 minutes, n = 7).

CONCLUSION

Mechanical ICE is effective in guiding transseptal puncture in PTMC.

Echocardiography-guided interventions

A major advantage of echocardiography over other advanced imaging modalities (magnetic resonance imaging, computed tomographic angiography) is that echocardiography is mobile and real time. Echocardiograms can be recorded at the bedside, in the cardiac catheterization laboratory, in the cardiovascular intensive care unit, in the emergency room-indeed, any place that can accommodate a wheeled cart. This tremendous advantage allows for the performance of imaging immediately before, during, and after various procedures involving interventions. The purpose of this report is to review the use of echocardiography to guide interventions. We provide information on the selection of patients for interventions, monitoring during the performance of interventions, and assessing the effects of interventions after their completion. In this document, we address the use of echocardiography in commonly performed procedures: transatrial septal catheterization, pericardiocentesis, myocardial biopsy, percutaneous transvenous balloon valvuloplasty, catheter closure of atrial septal defects (ASDs) and patent foramen ovale (PFO), alcohol septal ablation for hypertrophic cardiomyopathy, and cardiac electrophysiology. A concluding section addresses interventions that are presently investigational but are likely to enter the realm of practice in the very near future: complex mitral valve repairs, left atrial appendage (LAA) occlusion devices, 3-dimensional (3D) echocardiographic guidance, and percutaneous aortic valve replacement. The use of echocardiography to select and guide cardiac resynchronization therapy has recently been addressed in a separate document published by the American Society of Echocardiography and is not further discussed in this document. The use of imaging techniques to guide even well-established procedures enhances the efficiency and safety of these procedures.

A comparison of echocardiographic modalities to guide structural heart disease interventions

Percutaneous techniques to treat structural heart disease are rapidly evolving based on innovative interventions and the considerable advancement in image guidance technology. While two-dimensional transthoracic and transesophageal echocardiography have been integral to procedural planning and execution, intracardiac and three-dimensional echocardiography supply unique visualization of target structures with a potential improvement in patient safety and procedural efficacy. The choice of image guidance modality is based on specific differences between imaging systems, as well as other variables including cost, patient safety, operator expertise, and complexity of procedure. We will compare the adjunctive imaging tools for structural heart disease interventions, with a focus on intracardiac echocardiography and real-time three-dimensional transesophageal echocardiography.

Intra-cardiac echocardiography guided trans-septal puncture in patients with dilated left atrium undergoing percutaneous transvenous mitral commissurotomy

Percutaneous transvenous mitral commissurotomy (PTMC) is an effective treatment for mitral stenosis, but trans-septal puncture carries a certain risk of complications. There have been few reports on phase-array intra-cardiac echocardiography (ICE) guidance in trans-septal puncture for PTMC, especially in patients with dilated left atrium or distorted anatomy. Herein, we report our preliminary experience with ICE-guided trans-septal puncture in patients with dilated left atrium (>or=5.5 cm) who underwent PTMC. From June 2005 to March 2006, there were nine consecutive patients with symptomatic mitral stenosis and left atrium size larger than 5.5 cm who underwent trans-septal puncture for PTMC with the ICE guidance in this institution by a same operator. The procedural and catheterization results were analyzed. Using ICE guidance, the success rate for trans-septal puncture was 100% for all patients with dilated left atrium (>or=5.5 cm). The trans-septal procedures were free of major and minor complications and the patients were not exposed to contrast medium. Mitral valve area increased significantly from 1.0+/-0.2 cm(2) to 1.9+/-0.2 cm(2). Our preliminary result showed that ICE safely and effectively guided trans-septal puncture for PTMC in patients with dilated left atrium (>or=5.5 cm), thus eliminating contrast medium usage and avoiding unnecessary longer X-ray exposure.

Intracardiac Echocardiography for Percutaneous Mitral Valve Repair in a Swine Model

BACKGROUND

High-quality live imaging assessment of cardiac valves and cardiac anatomy is crucial for the success of percutaneous catheter-based mitral valve (MV) repair techniques. We examined the use of intracardiac echocardiography (ICE) in providing online ICE images necessary for successful perctunaneous MV repair by Alfieri stitch technique-based percutaneous edge-to-edge device in a swine model.

METHODS

ICE was performed in 20 healthy adult pigs (90 +/- 8 kg, mean +/- SEM). A 10F ICE catheter was advanced through the left femoral vein and the right jugular vein. Images were obtained from the right atrium, left atrium, right ventricle, and pulmonary artery. Fluoroscopy was used to locate the position of ICE catheter tip in different imaging windows.

RESULTS

An echocardiographic protocol was developed for focused visualization of target cardiac structures during the process of percutaneous MV repair. This included visualization of interatrial septum to guide transeptal puncture; to confirm transit of guidewire into the left atrium, across the MV into the left ventricle and across the aortic valve into the aorta; to assist in central positioning of guide catheter in the left atrium above and then across MV leaflets; and to visualize middle scallops of anterior and posterior MV leaflets in short- and long-axis views. Finally, location and orientation of the orifice of the therapy catheter against each MV leaflet was visualized to enable successful capture of MV leaflets, to confirm successful deployment of suture and double orifice (figure of 8" appearance of MV, and finally to confirm central deployment of clip at the site of suture.

CONCLUSION

An ICE protocol was developed to visualize serial cardiac structures to guide deployment of suture into the A2-P2 scallops of the MV and to confirm final result before release of clip.