Transesophageal echocardiography (TEE) is a key imaging procedure used during multiple interventions performed in both cardiac catheterization and electrophysiology laboratories. Its use in these settings has become so common, in fact, that TEE is becoming regarded as less of an actual “procedure,” than simply another way to provide pictures for the interventionalist—not unlike the fluoroscopy machine. The difference, of course, is that the TEE probe must be invasively placed and then continually manipulated within the patient’s body during imaging. In this regard it bears more similarity to bronchoscopy than chest-wall echocardiography.
I was recently reminded of the potential difficulties involved with TEE probe insertion during a left atrial appendage occluder device procedure. After a few unsuccessful blind attempts in my intubated and anesthetized patient, I realized something did not feel right. I picked up a nearby video laryngoscope, which revealed the findings in Figure 1 . As it turns out, the patient had an undiagnosed Killian-Jamieson diverticulum, which is similar to the better-known Zenker’s, although generally smaller and significantly less common. Per the 2013 comprehensive TEE guidelines, this was considered an absolute contraindication, and the procedure was abandoned. Anecdotal stories aside, Zuchelli et al. recently studied 134 patients who were referred for upper endoscopy prior to TEE placement due to positive symptoms (mainly dysphagia or hematemesis), or had a history of difficult probe placement. They found that 15% of the patients ultimately had some absolute contraindication to performing a TEE exam. When in doubt, it certainly never hurts to look.
Of course the most feared complication of TEE, gastrointestinal perforation, is an extremely rare event. In fact, in the first large series examining the safety of TEE, published 25 years ago in this very journal, it was not reported at all in 1500 patients. However, that study was conducted in an ambulatory setting. Paralyzed and intubated patients, who can no longer complain of painful probe manipulations, have a much different risk profile. The major complication rate for intraoperative TEE has been reported as high as 1.2%, and significant swallowing dysfunction may be present in over 5% of patients following TEE use in cardiac surgery. In anesthetized patients, excessive and/or extreme probe manipulations may contribute to gastrointestinal tract injury; the physician operating the probe must be aware of these concerns.
The data on operative and non-operative TEE safety was thoroughly reviewed by Hilberath et al. in the November, 2010 issue of JASE . At that time, however, “operative” referred almost exclusively to those TEEs performed during the course of cardiac surgery. The operating room TEE sequence generally consists of baseline, off-CPB (cardiopulmonary bypass), and chest-closed exams, each with discrete periods of image acquisition typically lasting 10-20 minutes. On the other hand, when TEE is used to help guide catheter-based procedures, there can be extended periods of time where the probe is locked onto one or two particular views while the interventionalist is working. I can remember one of my colleagues straddling the C-arm for nearly three straight hours during the learning curve phase of a particular mitral valve intervention. Unlike fluoroscopy machines, which are required by law to record radiation exposure time, there is little data collected that can be used to assess the impact that these protracted TEE exams may have on patient safety.
The take-home message here is that we need to remember that just because TEE is common does not mean it is without risks. Medical judgement is required to assess those risks and weigh imaging concerns against potentially harmful probe maneuvers, including placing it altogether. It is interesting to note that the British Society of Echocardiography and the Association of Cardiac Anaesthetists have recently endorsed a safety checklist specifically for TEE. I commend them for formally recognizing that TEE is an invasive medical procedure, and implore our interventionalist colleagues not to forget that it is.
Roman Sniecinski, MD, FASE is an Associate Professor of Anesthesiology in the Division of Cardiothoracic Anesthesia at Emory University School of Medicine. He is the current Chair of the Council of Perioperative Echocardiography steering committee.