TEE versus ICE for LAAO: Is ICE just as nice?

Atrial fibrillation (AF) is one of the most common cardiac dysrhythmias which affects millions of people throughout the world with the prevalence of this disease rising as age increases.1 AF is associated with stroke and systemic thromboembolism which may be prevented by the administration of oral anticoagulation.2 With the primary drawback to oral anticoagulation being the risk of bleeding, the option of left atrial appendage occlusion (LAAO) has emerged as a welcome alternative to chronic anticoagulation for stroke prevention for a sizable percentage of patients with AF. Transesophageal echocardiography (TEE) is commonly used during LAAO procedures and confers real-time imaging capabilities which can facilitate safe deployment. In the event of a complication, TEE can assist in rapidly identifying the problem as it arises. As TEE is performed by an additional operator, the physician performing the LAAO may focus on the procedure without having the extra responsibility of acquiring the TEE images. This theoretically could improve efficiency for the operator performing the LAAO. When considering TEE guidance for LAAO procedures versus fluoroscopy alone, TEE would result in less fluoroscopy time, though fluoroscopy alone procedures are not the standard practice in the current era.3 Nonetheless, adverse events related to TEE can occur in as many as 3% of patients who undergo interventions for structural heart disease.4 Older patients have a higher incidence of complications, and these are the very patients that are a key cohort undergoing these procedures.5 As endoscopy studies have shown visible esophageal injury in 80% of patients undergoing TEE to help guide structural cardiac interventional procedures,6 there is concern that procedure-related events may exceed the rate of device-related adverse events; as such, consideration has been given to the alternative imaging modality of intracardiac echo (ICE) to guide these LAAO procedures. In this issue of Journal of Cardiovascular Electrophysiology, Dr. Juan Carlos Diaz and colleagues present a meta-analysis that reports on the impact of ICE versus TEE guidance for LAAO procedures.7 Their report is timely given the significant number of LAAO procedures being performed. Though TEE is the mainstay adjunctive imaging modality for LAAO procedures, TEE may impose impediments and challenges to the efficiency of LAAO procedures. With a goal of trying to circumvent some of these challenges, ICE has emerged as an alternative to TEE; ICE is being used with increasing frequency in experienced centers. With respect to the achievement of LAAO, a reassuring finding of the meta-analysis was that using ICE results in similar procedural success compared with TEE. Moreover, there was no significant difference in the incidence of procedure-related complications when ICE was compared with TEE. As an operator contemplates the possibility of using ICE-guided closure and considers the additional responsibility of ensuring the obtainment of sufficient images, the findings of the meta-analysis are indeed reassuring. With respect to electrophysiologists considering making the switch from TEE to ICE as the primary method of guiding LAAO procedures, an experience with ablation of AF implies that the operator likely already has a great deal of experience and is comfortable with the routine use of ICE. The key to intraprocedural success when using ICE guidance is getting the ICE catheter into the left atrium. This should be done ideally through the same transseptal hole as the LAAO delivery sheath or if this is not possible, through a dedicated separate transseptal puncture. Going through a separate patent foramen ovale is not advised; when the ICE catheter enters the LA through this route, the available images are limited. ICE images taken via a patent foramen ovale are not of sufficient quality to reliably and sufficiently visualize device deployment nor of sufficient quality to ensure the achievement of a desired position, good stability, and adequate seal without leaks. The method of getting the ICE into the left atrium and the basic views used during LAAO has been well described.8 As a suggestion for consideration, electrophysiologists wishing to use ICE guidance for LAAO could begin incorporating the use of getting into the left atrium during ablation of AF or left-sided atrial tachyarrhythmias. Given the frequency with which these procedures are performed in the current day, there should be adequate opportunity to gain experience with this critical step. In our experience, it is important to be able to get three key views, from the left superior pulmonary vein, the body of the left atrium, and the lateral mitral valve which corresponds to 45°, 90°, and 135° views on TEE, respectively. An ICE view that corresponds to the 0° view on TEE can also be obtained by performing a counterclockwise rotation from the body of the left atrium, which results in visualization of the short axis of the aortic valve; from there, the addition of the right tilt will reveal the left atrial appendage. If there is any difficulty achieving the key three views, this additional “0°” view can be helpful. In our experience, the optimal view for deployment is achieved by placing the ICE in the left superior pulmonary view. For the reader's benefit, we have included a short video that shows the advancement of the ICE probe into the left atrium and the deployment of a Boston Scientific Watchman FLX device (Supporting Information Video). When comparing TEE guidance to ICE guidance, the question of cost has been brought up, though this difference has not been found to be significant.9 When considering the time expended to perform these procedures, there were no significant differences in the procedure time when comparing ICE to TEE. There were also no significant differences in fluoroscopy time for ICE versus TEE, implying no greater reliance on fluoroscopy when ICE is employed. One noteworthy finding was the in-room time was significantly reduced when ICE was used compared with TEE. While there was variance in the extent of this finding, it has potential implications for lab efficiency. The reduced in-room time for patients undergoing ICE-guided LAAO time is likely explained by the avoidance of reliance on anesthesia services to provide general anesthesia or deep sedation. With LAAO procedures on the rise, improving lab efficiency will allow for more patients to undergo needed procedures in a timely fashion. In our experience, by performing LAAO procedures using ICE, conscious sedation can often be used. This results in an appreciable decrease in total time in the room and a reduction in adverse effects associated with general anesthesia or deeper levels of sedation. By using a vascular closure device, patients are usually discharged home within 2 h. The relatively short in-room time afforded by ICE, reduced risk of complications related to the avoidance of general anesthesia and deeper levels of sedation, and quick ambulation afterwards and early discharge provides for an enhanced patient experience. When considering the findings of follow-up imaging, the meta-analysis showed that the incidence of peridevice leaks was similar in ICE and TEE groups. More residual atrial septal defects were seen in the ICE-guided group, but this finding remains of unclear clinical consequence. While this was not the first meta-analysis related to ICE guidance for LAAO procedures,10, 11 this meta-analysis provides information on lab efficiency, peridevice leaks, and residual interatrial septal defects. The reassuring findings of this meta-analysis may help inform decision making for an operator considering making the switch from TEE guidance to ICE guidance. Limitations mentioned by the authors include: (1) the observational nature of the studies which could result in the presence of bias, (2) ICE-guided procedures being performed by operators with significant TEE-guided procedural experience with the confounding variable being operator experience, which could reduce the generalizability of the findings to less experienced operators, (3) publication bias, and (4) significant heterogeneity seen for a number of the studied outcomes. Despite these limitations, the meta-analysis seems to have been thoughtfully performed and provides useful information for operators contemplating employing an ICE-guided approach to LAAO. Further data will hopefully confirm these findings, allowing the careful adoption of this technique for more patients seeking to undergo LAAO. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.