Integrated x-ray and echocardiography imaging for structural heart interventions

Echocardiographic guidance in transcatheter structural cardiac interventions

Catheter-based treatment of structural heart diseases (SHD) has seen tremendous advances in the past decades, thanks to the development of new devices and advances in imaging techniques. Today, we have an extensive armamentarium of imaging tools for preprocedural planning, intraprocedural guidance and follow-up of SHD. Intraprocedural guidance is based mainly on transoesophageal echocardiography; however, other imaging modalities are used as complementary or alternative techniques, each of them with its strengths and weaknesses. Thus, a multimodality imaging approach provides added values in this setting. As the field of imaging parallels the continuous technical improvements, this review will describe the state of the art imaging techniques, focusing on echocardiography during procedural guidance of the most common catheter-based interventions, providing tips and tricks for interventional cardiologists: in particular, how to guide transseptal crossing; left atrial appendage closure; transcatheter mitral or tricuspid valve repair or replacement; percutaneous closure of patent foramen ovale and atrial defects; and percutaneous closure of paravalvular leaks. Open challenges for the near future are the need for physicians with specific technical skills and competencies in SHD imaging, more attention to high levels of radiation exposure, and optimisation of intraprocedural and post-procedural evaluation.

Real-time echocardiography-fluoroscopy fusion imaging for left atrial appendage closure: prime time for fusion imaging?

BACKGROUND

Real-time echocardiography-fluoroscopy fusion imaging (FI) merges real-time echocardiographic imaging with fluoroscopic images allowing intuitive anatomical spatial orientation during structural heart disease interventions. We aimed to assess the safety and efficacy of FI during percutaneous left atrial appendage closure (LAAC).

METHODS

34 consecutive patients before (-FI) and 121 patients after (+FI) the introduction of FI for LAAC were included in a single-centre study. In-hospital safety parameters were analysed according to adverse event (AE) definition of the Munich consensus document and procedure-related parameters were assessed for efficacy. An ANCOVA was performed to investigate the influence of a learning curve.

RESULTS

Time until successful transseptal puncture was significantly reduced as well as total procedure time and the amount of contrast agent used (+FI/-FI:17 ± 6.35 min vs. 22 ± 8.33 min, p = 0.001; +FI/-FI: 50 min IQR 43 min - 60 min vs. 57 min IQR 45 min -70 min; p = 0.013; +FI/-FI: 70 mL, IQR 55 ml-90 mL vs. 152 mL, IQR 107 mL - 205 mL; p < 0.001). However, fluoroscopy time and dose-area product did not differ between both groups. There was no significant difference in the occurrence of in-hospital adverse events (+FI/-FI: 2.5% vs. 0%; p = 0.596). The ANCOVA revealed that the learning curve does not affect procedural efficacy parameters such as procedure time, time to transseptal puncture, amount of contrast agent and dose-area product.

CONCLUSIONS

FI for LAAC reduces the total procedure time, the time to successful transseptal puncture and periprocedural amount of contrast agent.

Systematic Fluoroscopic-Echocardiographic Fusion Imaging Protocol for Transcatheter Edge-to-Edge Mitral Valve Repair Intraprocedural Monitoring

BACKGROUND

Whether fluoroscopic-echocardiographic fusion imaging (FI) might offer added value for intraprocedural guidance during transcatheter edge-to-edge mitral valve repair is yet unknown, and few data exist regarding the safety and feasibility of this novel technology.

METHODS

The aim of this single-center study was to test and validate a FI protocol for intraprocedural monitoring of transcatheter edge-to-edge mitral valve repair and assess its clinical usefulness. Eighty patients underwent MitraClip implantation using FI guidance (FI+) for either degenerative (35%) or functional (65%) mitral regurgitation and were compared with the last 80 patients before FI introduction, treated using conventional echocardiography and fluoroscopic monitoring (FI-).

RESULTS

The number of patients treated for functional and degenerative mitral regurgitation was similar between the FI+ and FI- groups, as well as the number of devices implanted (1.51 ± 0.5 vs 1.58 ± 0.6, P = .46). The prevalence of complex mitral anatomy for percutaneous repair was high (32.5%, up to 39.2% in the hybrid arm). Fluoroscopy time was significantly lower in FI+ patients (37.3 ± 14.6 vs 48.3 ± 28.3 min, P = .003), but not kerma area product (91.5 ± 74.1 vs 108.8 ± 105.0 Gy · cm², P = .23) or procedural time (92.2 ± 36.1 vs 103.1 ± 42.7 min, P = .086). After adjusting for confounding factors (MitraClip XT device and complex anatomy), FI reduced fluoroscopy time (coefficient = -10.4 min; 95% CI, -18.03 to -2.82; P = .007) and improved procedural success at the end of the procedure (odds ratio, 2.87; 95% CI, 1.00 to 8.24; P = .049) and discharge (odds ratio, 2.24; 95% CI, 1.04 to 4.80; P = .039). Rates of periprocedural complications were similar in both groups (8.9% vs 13.0%, P = .40).

CONCLUSIONS

The authors describe the systematic use of an FI protocol for intraprocedural guidance during transcatheter edge-to-edge mitral valve repair, demonstrating a reduction in fluoroscopy time and an improvement in procedural success in a population with a high prevalence of challenging mitral anatomy for percutaneous repair.

3-Dimensional Echocardiography: Latest Developments and Future Directions

The ongoing refinements in 3-dimensional (3D) echocardiography technology continue to expand the scope of this imaging modality in clinical cardiology by offering new features that stem from the ability to image the heart in its complete dimensionality. Over the years, countless publications have described these benefits and tested new frontiers where 3D echocardiographic imaging seemed to offer promising ways to improve patients' care. These include improved techniques for chamber quantification and novel ways to visualize cardiac valves, including 3D printing, virtual reality, and holography. The aims of this review article are to focus on the most important developments in the field in the recent years, discuss the current utility of 3D echocardiography, and highlight several interesting future directions.

The growing role of echocardiography in interventional cardiology: The present and the future

As structural heart disease interventions continue to evolve to a sophisticated level, accurate and reliable imaging is required for pre-procedural selection of cases, intra-procedural guidance, post-procedural evaluation, and long-term follow-up of patients. Traditionally, cardiovascular procedures in the catheterization laboratory are guided by fluoroscopy and angiography. Advances in echocardiography can overcome most limitations of conventional imaging modalities and provide successful completion of each step of any catheter-based treatment. Echocardiography's unique characteristics rendered it the ideal technique for percutaneous catheter-based procedures. The purpose of this review is to demonstrate the use of the most common and up-to-date echocardiographic techniques in recent non-coronary percutaneous interventional procedures, underlining its inevitable and growing role, as well as illustrating areas of weakness and limitations, and to provide future perspectives.

Safety and efficacy of transseptal puncture guided by real-time fusion of echocardiography and fluoroscopy

Aims

Visual guidance through echocardiography and fluoroscopy is crucial for a successful transseptal puncture (TSP) in a prespecified region of the fossa ovalis. The novel EchoNavigator system Release II (EchoNav II, Philips Healthcare, Andover, Massachusetts, USA) enables the real-time fusion of fluoroscopic and echocardiographic images. We evaluated this new imaging method in respect to safety and efficacy of TSP during MitraClip implantation and left atrial appendage closure.

Methods

Forty-four patients before (−EchoNav) and 44 patients after (+EchoNav) the introduction of real-time fusion were included in our retrospective, single-centre study. The primary endpoint was the occurrence of adverse events due to TSP. Secondary endpoints were successful puncture at the prespecified region and time until TSP (min).

Results

In both groups TSP was performed successfully in the prespecified region and no adverse events occurred during or due to the accomplishment of TSP. Time until TSP was significantly reduced in the +EchoNav group in comparison with the EchoNav group (18.48 ± 5.62 min vs. 23.20 ± 9.61 min, p = 0.006).

Conclusions

Real-time fusion of echocardiography and fluoroscopy proved to be as safe and successful as standard best practice for TSP. Moreover, efficacy was improved through significant reduction of time until TSP.

Rotational Angiography Based Three-Dimensional Left Atrial Reconstruction: A New Approach for Transseptal Puncture

AIM

Rotational angiography is a well-known method for the three-dimensional (3-D) reconstruction of left atrium and pulmonary veins during left-sided atrial arrhythmia ablation procedures. In our study, we aimed to review our experience in transseptal puncture (TSP) using 3-D rotational angiography.

METHODS

We included a total of 271 patients who underwent atrial fibrillation ablation using cryoballoon. Rotational angiography was performed to get the three-dimensional left atrial and pulmonary vein reconstructions using cardiac C-arm computed tomography. The image reconstruction was made using the DynaCT Cardiac software (Siemens, Erlangen, Germany).

RESULTS

The mean age of the study population was 61 ± 10 years. The indications for left atrial arrhythmia ablation were paroxysmal AF in 140 patients (52%) and persistent AF patients in 131 (48%) patients. The success rate of TSP using only rotational guidance was (264/271 patients, 97.4%). In the remaining seven patients, transesophageal guidance was used after the initial attempt due to thick interatrial septum in five patients and difficult TSP due to abnormal anatomy and mild pericardial effusion in the remaining two patients. Mean fluoroscopy dosage of the rotational angiography was 4896.4 ± 825.3 μGym(2). The mean time beginning from femoral vein puncture to TSP was 12.3 ± 5.5 min.

CONCLUSION

TSP guided by rotational angiography is a safe and effective method. Our results indicate that integration of rotational angiographic images into the real-time fluoroscopy can guide the TSP during the procedure.

Transcathether Valve Replacement and Valve Repair

Transcatheter aortic valve replacement for treatment of aortic stenosis has now become an accepted alternative to surgical valve replacement for some patients. In addition, transcatheter mitral valve repair is also routinely used in high surgical risk patients with mitral regurgitation. Other transcatheter procedures are in rapid development. The current review attempts to summarize the procedures and echocardiographic imaging used for transcatheter valve replacement or valve repair.

Hybrid Imaging in the Catheter Laboratory: Real-time Fusion of Echocardiography and Fluoroscopy During Percutaneous Structural Heart Disease Interventions

Percutaneous catheter-based techniques for the treatment of structural heart disease are becoming more complex, and current imaging techniques have limitations: while fluoroscopy gives poor visualisation of cardiac anatomical structures, echocardiography is limited in its ability to detect the position of catheters and devices. The EchoNavigator® (Philips) live image guidance tool is a novel system that integrates real-time echocardiography with fluoroscopic X-ray imaging, optimising the guidance and positioning of devices. Use of the EchoNavigator system facilitates improved understanding of anatomical structures while showing enhanced visualisation of catheter and device movements. Early clinical experience suggests that the technology is feasible and safe, and provides enhanced understanding of the relationship between soft tissue anatomy and catheter devices in structural heart disease. The use of the EchoNavigator system can improve the confidence of interventional cardiologists in the targeting and positioning of devices in percutaneous interventions in structural heart disease, and has the potential to reduce procedural time, reduce the dosage of contrast and radiation and increase safety in the performance of procedural steps.

The Changing Paradigm in the Treatment of Structural Heart Disease and the Need for the Interventional Imaging Specialist

Percutaneous interventions in structural heart diseases are emerging rapidly. The variety of novel percutaneous treatment approaches and the increasing complexity of interventional procedures are associated with new challenges and demands on the imaging specialist. Standard catheterisation laboratory imaging modalities such as fluoroscopy and contrast ventriculography provide inadequate visualisation of the soft tissue or three-dimensional delineation of the heart. Consequently, additional advanced imaging technology is needed to diagnose and precisely identify structural heart diseases, to properly select patients for specific interventions and to support fluoroscopy in guiding procedures. As imaging expertise constitutes a key factor in the decision-making process and in the management of patients with structural heart disease, the sub-speciality of interventional imaging will likely develop out of an increased need for high-quality imaging.

Recent advances in echocardiography for valvular heart disease

Echocardiography is the imaging modality of choice for the assessment of patients with valvular heart disease. Echocardiographic advancements may have particular impact on the assessment and management of patients with valvular heart disease. This review will summarize the current literature on advancements, such as three-dimensional echocardiography, strain imaging, intracardiac echocardiography, and fusion imaging, in this patient population.

Initial clinical experience using the EchoNavigator®-system during structural heart disease interventions

AIM: To present our initial clinical experience using this innovative software solution for guidance of percutaneous structural heart disease interventions.

METHODS: Left atrial appendage, atrial septal defect and paravalvular leak closure, transaortic valve repair and MitraClip^® procedures were performed in the catheter laboratory under fluoroscopic and echocardiographic guidance. The two-dimensional and three-dimensional images generated by the transesophageal echocardiography probe were interfaced with the fluoroscopic images in real-time using the EchoNavigator^®-system.

RESULTS: The application of the novel image fusion technology was safe and led to a better appreciation of multimodality imaging guidance due to improved visualization of the complex relationship between catheter devices and anatomical structures.

CONCLUSION: The EchoNavigator^®-system is a feasible and safe tool for guidance of interventional procedures in structural heart disease. This innovative technology may improve confidence of interventional cardiologists in targeting and positioning interventional devices in order to increase safety, accuracy, and efficacy of percutaneous interventions in the catheter laboratory.

The left atrial appendage: anatomy, function, and noninvasive evaluation

The left atrial appendage (LAA) is a finger-like extension originating from the main body of the left atrium. Atrial fibrillation (AF) is the most common clinically important cardiac arrhythmia, occurring in approximately 0.4% to 1% of the general population and increasing with age to >8% in those >80 years of age. In the presence of AF thrombus, formation often occurs within the LAA because of reduced contractility and stasis; thus, attention should be given to the LAA when evaluating and assessing patients with AF to determine the risk for cardioembolic complications. It is clinically important to understand LAA anatomy and function. It is also critical to choose the optimal imaging techniques to identify or exclude LAA thrombi in the setting of AF, before cardioversion, and with current and emerging transcatheter therapies, which include mitral balloon valvuloplasty, pulmonary vein isolation, MitraClip (Abbott Laboratories, Abbott Park, Illinois) valve repair, and the implantation of LAA occlusion and exclusion devices. In this review, we present the current data regarding LAA anatomy, LAA function, and LAA imaging using the currently available noninvasive imaging modalities.

Hybrid Imaging During Transcatheter Structural Heart Interventions

Fusion of different imaging modalities has gained increasing popularity over the last decade. However, most fusions are done between static rather than dynamic images. In order to adequately visualize the complex three-dimensional structures of the beating heart, high-temporal and spatial image resolutions are mandatory. Currently, only the combination of transesophageal echocardiography with fluoroscopy allows real-time image fusion of high quality during structural heart disease (SHD) interventions. The use of markers as well as real-time image overlay greatly facilitates communication between SHD team members and potentially increases procedural success while reducing radiation dose and use of contrast. However, to date there is only limited evidence that fusion imaging improves safety and outcomes of SHD interventions. This review highlights the benefits of fusion imaging during SHD interventions such as transseptal puncture and closure of atrial septal defects and left atrial appendage as well as interventions on the mitral and aortic valve.