TEE-induced esophageal perforation can occur even when TEE examination is smooth [4, 6,7,8,9,10,11]. In the present case, probe insertion was smooth, but we encountered some difficulties in obtaining the transgastric short-axis view during surgery. Although NG tube-induced perforation could not be ruled out completely, it was reasonable to think that the perforation was caused by TEE probe based on our observations, the relatively larger perforation size, and the unusually difficult TEE manipulation.
Esophageal perforation during intraoperative TEE is mostly caused by direct mechanical trauma related to probe insertion and manipulation [4]. Prolonged, continuous pressure and thermal energy from a probe can also damage esophageal tissue, resulting in indirect mechanical trauma. Predisposing factors include anatomical and pathological changes in the esophagus, including strictures, diverticula, tumors, varices, distortions due to an enlarged LA or thoracic aortic aneurysm, pathologic tissue fragility due to chronic steroid therapy or prior chest radiation, prior esophageal surgery, and decreased local circulation due to atherosclerosis [1, 4, 5]. A giant LA was the most significant risk factor in the present case.
Gross cardiomegaly characteristic of giant LA can distort and cause thinning of the esophageal wall [4, 6]. Massey et al. have reported iatrogenic esophageal perforation in a patient with a grossly enlarged LA that was 16.5 cm in diameter [6]. However, the manner by which a giant LA distorts the esophagus is yet to be determined. We retrospectively constructed 3D images of the esophagus from the chest CT taken 2 months before the operation using a Synapse Vincent™ (Fuji Film, Tokyo, Japan). The images clearly indicated that the enlarged LA markedly compressed the esophagus rightward and backward, resulting in a twisted distortion (Fig. 2). The figure also showed that the most narrowing part was the middle esophagus. However, the perforation occurred below the middle esophagus. It might be postulated that undue strain by the TEE probe could be placed on the lower esophagus as enlarged LA caused the bend of the esophagus at almost right angle.
We determined the course of the esophagus based on chest CT in patients with MS who underwent cardiac surgery at our hospital during the last 7 years (from 2012 to 2018). Among 33 patients, two patients, including the present patient, had a twisted distortion. Thus, the twisted esophagus in the present patient seemed to be unusual, but it should be noted that an enlarged LA may infrequently cause severe distortion.
Early detection of esophageal perforation is important for improving outcomes. However, detection is often delayed, especially with intraoperative TEE [4, 6,7,8,9,10,11]. A systematic review reported that the median time until detection was 2.5 days [4]. The presenting symptoms varied by case, including hypotension, shock, fever, dyspnea, hypoxemia, leukocytosis, chest pain, pericardial or pleural effusion, pneumoperitoneum, pneumothorax, and pneumomediastinum [6,7,8,9,10,11]. There were several clinical findings that might be related to esophageal perforation, such as difficulty in visualizing the transgastric short-axis view, unusual NG tube position on postoperative chest radiography, and no fluid drainage from the NG tube in the ICU. Careful check of the chest X-ray and checking the pH of the fluid from NG tube after the cardiac surgery might be a hint to suspect esophageal perforation and might have led earlier detection.
For the prevention of esophageal perforation, it is important to recognize the risk factors listed above (the second paragraph in the “Discussion” section). Esophageal strictures, tumor, diverticula, tracheoesophageal fistula, post-esophageal surgery, and esophageal trauma are absolute contraindications to TEE [5, 12]. Patients with relative contraindications such as an enlarged LA should be evaluated on a case-by-case basis and appropriate precautions should be considered. [5]. The appropriate precautions include not advancing probe past the mid-esophagus, limiting probe manipulation and examination, considering other imaging modalities (e.g., epicardial echocardiography), obtaining gastroenterology consultation using a smaller probe, and using the most experienced operator [5, 12]. Unfortunately, we did not notice such a twisted distortion before the operation. Attempts to obtain the LV short-axis view would have been minimized or would not have been performed had we identified such a marked esophageal distortion before cardiac surgery. Preoperative evaluation of the course of the esophagus might provide information that is helpful for avoiding this life-threatening complication.
