Misinterpretation of a movable mass attached to the aortic valve imaged by transoesophageal echocardiography

Abstract

Editor, Intraoperative transoesophageal echocardiography (TEE) is a useful tool not only for monitoring surgical patients but also for evaluating and diagnosing cardiac lesions during surgery and guiding surgical approaches. Several reports have described the incidental identification of cardiac lesions using TEE.1–3 This case alerts echocardiographers regarding the possible misinterpretation of an apparent movable cardiac mass. A 76-year-old man was scheduled for coronary artery bypass graft (CABG) surgery. He was admitted to our hospital and diagnosed with acute myocardial infarction 2 months prior to the scheduled surgery. Coronary angiography revealed total occlusion in segments 1 and 6 and significant stenosis (90%) in segment 13. The total occlusion in segment 1 was alleviated by percutaneous coronary intervention, resulting in nonsignificant stenosis (25%). Preoperative transthoracic echocardiography (TTE) revealed an ejection fraction of 67% with mild hypokinesis of the inferior wall, trivial mitral regurgitation and no abnormalities of the aortic valve. TEE was not performed preoperatively. After induction of anesthesia for the CABG surgery, TEE (ACUSON-CV70, Siemens, Tokyo, Japan), which was equipped with two-dimensional imaging with colour flow Doppler, was performed. A midoesophageal, modified long-axis view of the aortic valve revealed a 6.5 mm × 3.5 mm, high-echoic, mobile, pedunculated mass attached to the noncoronary cusp (Fig. 1 and Video Loop 1, https://links.lww.com/EJA/A1). The movement of the mass appeared to be synchronized with the aortic valve. Colour flow Doppler exhibited only trivial aortic regurgitation. The mass was visible in the wide range of the multiplane angle from the modified long-axis view to the true long-axis view of the aortic valve. A short-axis view of the aortic valve revealed mild hypertrophy of the noncoronary cusp at the level of the aortic valve (Fig. 2 and Video Loop 2, https://links.lww.com/EJA/A2). The view was unable to provide any clear images of the area proximal to the aortic valve due to the appearance of the basal left ventricle, and we were unable to detect the mass there. The movable mass was interpreted as likely representing a tumour, thrombus, vegetation or Lambl's excrescences. After detailed discussion with the cardiac surgeon regarding the movable mass and completion of distal anastomosis of CABG, the aorta was opened and the aortic valve was observed through the transaortic approach. Although no abnormal structures were attached to the aortic valve, part of the noncoronary cusp leaflet had yellowish degenerative bulging hypertrophy. After the aorta was closed and the cardiopulmonary bypass was completed, the aortic valve was again evaluated by TEE. The mass-like structure was still visible in the same view as it was during the pre-bypass period.Fig. 1Fig. 2Accurate diagnosis of the mass-like structure was necessary in this case because a pedunculated, movable mass carries the risk of life-threatening complications such as stroke, embolism and acute valvular dysfunction. TEE is a useful imaging modality for assessment of movable intracardiac masses. With TEE, optimal high resolution and proximity between the transducer and the heart sometimes provide superior evaluation of the characteristics of a movable cardiac mass compared with TTE. It has been reported that a fibroelastoma attached to the aortic valve was incidentally identified with intraoperative TEE although it was not shown by preoperative TTE.2,3 However, in our case, the hypertrophic region of the aortic valve leaflet was misinterpreted as a movable cardiac mass. It was postulated that the bulging hypertrophic region of the noncoronary cusp was imaged only during diastole, this being interpreted as a movable mass during the cardiac cycle. Misinterpretation of cardiac lesions by TEE has been reported.4,5 A mobile mass on a prosthetic mitral valve observed by TEE was reportedly misinterpreted as vegetation when it was actually a pannus.4 In our case, the hypertrophic region of the valve appeared to be a mass-like structure that moved with the cardiac cycle, as viewed by TEE. This is one possible pitfall of TEE. It is extremely important, though sometimes difficult, to differentiate mass-like structures attached to the aortic valve. This case has an important clinical message for the interpretation of a movable mass on the aortic valve with TEE.