Anesth Pain Med Search


Anesth Pain Med > Volume 11(4); 2016 > Article
Jun, Lee, Choi, Kim, Lee, Baek, and Chung: Accidental left atrial appendage thrombus detected by intraoperative transesophageal echocardiography during coronary artery bypass graft -A case report-


A 77-year-old woman was scheduled for a coronary artery bypass graft. Her preoperative transthoracic echocardiographic (TTE) examination revealed an enlarged left atrium with reduced systolic dysfunction (ejection fraction: 38%), moderate global hypokinesia of the left ventricle, and moderate mitral and tricuspid regurgitation. No thrombus was visualized on the preoperative TTE. However, the intraoperative transesophageal echocardiography performed before the cardiopulmonary bypass revealed a thrombus of approximately 1.3 × 1.8 cm in the left atrial appendage (LAA). The LAA thrombus was removed, an internal suture was placed on the LAA before the coronary artery bypass grafting, and the main operation was performed successfully. The patient was transferred to the intensive care unit to receive postoperative care. She was extubated 4 h after the surgery and was transferred to the general ward on postoperative day 3 without any neurological sequelae.


The utility of intraoperative transesophageal echocardiography (TEE) for patients undergoing coronary artery bypass grafting (CABG) has been well established [1]. TEE provides important information for the surgical and hemodynamic management of patients before and after cardiopulmonary bypass (CPB) [2]. We report a case of incidental intraoperative TEE detection of a left atrial appendage (LAA) thrombus in a patient with atrial fibrillation (AF) scheduled for an on-pump CABG. The timely removal of the thrombus prevented fatal embolic complications.


A 77-year-old woman presented with a history of dyspnea on exertion (NYHA class III) over the past 3 months. She had been diagnosed with hypertension and AF (treated with 50 mg losartan and 100 mg aspirin) 1 year prior. Her laboratory work showed elevated levels of serum troponin I (0.245 ng/ml), creatine kinase-MB (4.55 ng/ml), and brain natriuretic peptide (958.2 pg/ml). The preoperative transthoracic echocardiographic (TTE) examination revealed an enlarged left atrium (LA) with reduced systolic dysfunction (ejection fraction: 38%), moderate global hypokinesia of the left ventricle, and moderate mitral and tricuspid regurgitation. No thrombus was visualized on the preoperative TTE (Video 1). As the coronary artery angiography showed triple vessel disease with severe stenosis of the proximal left anterior descending artery, the patient was scheduled for an on-pump CABG.
Upon arrival in the operating room, basic monitors - including a precordial five-lead electrocardiograph and a pulse oximeter - were attached. An arterial catheter was inserted in the right radial artery after local anesthesia was induced. The anesthesia was induced with titrated doses of midazolam, sufentanil, and sevoflurane. Cisatracurium was administered to facilitate the endotracheal intubation with a 6.5 mm cuffed oral endotracheal tube. No significant hemodynamic disturbances occurred during the anesthetic induction. A TEE probe (X7-2t Transducer, Philips Medical Systems, USA) was inserted for cardiac examination. While other findings were consistent with the preoperative TTE assessment, the TEE image in the mid-esophageal LAA view showed a small immobile thrombus of approximately 1.3 × 1.8 cm in the LAA (Fig. 1) that had been dislodged by cardiac manipulation during the dissection of the left internal mammary artery (Fig. 2) (Video 2). This prompted a change in the surgical plan. We decided to open the LA and remove the thrombus prior to the CABG.
Fig. 1
Transesophageal echocardiography image obtained before CPB showing small immobile thrombus (white arrow) of 1.3 × 1.8 cm in the LAA. CPB: cardiopulmonary bypass, LAA: left atrial appendage.
Fig. 2
Transesophageal echocardiography image obtained before CPB showing dislodged thrombus (white arrow) after cardiac manipulation. CPB: cardiopulmonary bypass.
After CPB was established, the 1.5 × 1 cm LAA thrombus (as measured) was removed, and the LAA was ligated. CABG was performed afterwards. After completing the proximal graft anastomoses, the patient was weaned from the CPB with an inotropic infusion of 5 μg/kg/min dobutamine and 0.5 μg/kg/min nitroglycerin. The LAA thrombus was no longer observed (Fig. 3). The patient was transferred to the intensive care unit to receive postoperative care. She was extubated 4 h after the surgery and was transferred to the general ward on postoperative day 3 without any neurological sequelae.
Fig. 3
Transesophageal echocardiography image obtained after CPB showing no thrombus in the LA and ligated LAA. CPB: cardiopulmonary bypass, LA: left atrium, LAA: left atrial appendage.


The importance of TEE as a monitoring and diagnostic tool for perioperative management has gained prominence [3]. In the present case, intraoperative TEE provided important information that led to the alteration of the surgical strategy [4,5]. A previous study demonstrated that intraoperative TEE evidenced new pathological findings in 13% of patients undergoing CABG surgery, leading to a change in the surgical approach in 5-6% of these cases [1]. In our case, we incidentally detected a LAA thrombus from the intraoperative TEE prior to CPB in a patient scheduled for CABG. This allowed for timely removal of the thrombus and prevented fatal embolic complications after the operation.
TTE and TEE are common imaging modalities used in cardiac perioperative settings. TTE and TEE are complementary in their ability to provide better images of precise structures. Whereas TTE provides superior imaging of anterior structures such as the pulmonic valve, right ventricular outflow tract, right ventricle, and anterior pericardium, TEE provides superior spatial resolution of the posterior cardiac structures, such as the interatrial septum, mitral valve, and left atrium [6]. In patients with AF, thrombi are most often located in the LAA [7]. Due to the posterior location of the LA and the frequent difficulty in imaging the LAA, the detection of LAA thrombi with TTE is not often successful. TTE only presents a 69% sensitivity for the identification of left atrial thrombi, with more limited success for LAA thrombi [8]. Meanwhile, as its close proximity to the esophagus allows the use of a higher frequency transducer, TEE enables clear visualization of the LAA [8]. In a study comparing the two intraoperative observation methods, all 9 LAA thrombi were undetected on the TTE but were clearly identified by the TEE, with a sensitivity of 100% and a specificity of 99% [9]. The exclusion of LAA thrombi with TEE is of particular importance before open heart surgery. Indeed, the safety of the procedure is directly influenced by the presence of LAA thrombi as it involves LAA manipulation that might cause embolization of the LAA content [10].
The incidence of LAA thrombi in patients with atrial fibrillation is about 10% [11]. If a thrombus in the LAA embolizes, stroke can occur. Moreover, embolism to the lower extremities, the kidney, and the spleen or mesenteric vessels can also occur [12-14]. The risk of stroke in patients with AF depends on the risk profile of the population examined and on the concomitant antithrombotic therapies. The CHADS2 (congestive heart failure, hypertension, age > 75 years, diabetes mellitus, stroke or transient ischemic attack) score is a good predictor of the stroke risk in patients with AF [15]. An increased left atrial volume (≥ 50 ml), decreased ejection fraction (< 56%), and increased brain natriuretic peptide level (> 75 pg/ml) are significantly correlated with an increased risk of LAA thrombus, even in patients with a low CHADS2 score [15]. As our patient had a CHADS2 score of 3, an increased left atrial volume, a decreased ejection fraction, and an increased brain natriuretic peptide level, the risk of thromboembolic events was high.
In summary, the intraoperative TEE identified an LAA thrombus previously undiagnosed by the TTE. Comprehensive intraoperative TEE is particularly useful for evaluation of the posterior cardiac structures, as it provides superior spatial resolution.



1. Qaddoura FE, Abel MD, Mecklenburg KL, Chandrasekaran K, Schaff HV, Zehr KJ, et al. Role of intraoperative transesophageal echocardiography in patients having coronary artery bypass graft surgery. Ann Thorac Surg 2004; 78: 1586-90. PMID: 10.1016/j.athoracsur.2004.05.001. PMID: 15511437.
crossref pmid
2. Click RL, Abel MD, Schaff HV. Intraoperative transesophageal echocardiography:5-year prospective review of impact on surgical management. Mayo Clin Proc 2000; 75: 241-7. PMID: 10.1016/S0025-6196(11)65027-1. PMID: 10.4065/75.3.241. PMID: 10725949.
crossref pmid
3. Poterack KA. Who uses transesophageal echocardiography in the operating room? Anesth Analg 1995; 80: 454-8. PMID: 10.1097/00000539-199503000-00004. PMID: 7864407.
crossref pmid
4. Minhaj M, Patel K, Muzic D, Tung A, Jeevanandam V, Raman J, et al. The effect of routine intraoperative transesophageal echocardiography on surgical management. J Cardiothorac Vasc Anesth 2007; 21: 800-4. PMID: 10.1053/j.jvca.2007.04.012. PMID: 18068055.
crossref pmid
5. Eltzschig HK, Rosenberger P, Löffler M, Fox JA, Aranki SF, Shernan SK. Impact of intraoperative transesophageal echocardiography on surgical decisions in 12,566 patients undergoing cardiac surgery. Ann Thorac Surg 2008; 85: 845-52. PMID: 10.1016/j.athoracsur.2007.11.015. PMID: 18291154.
crossref pmid
6. Shillcutt SK, Bick JS. Echo didactics: a comparison of basic transthoracic and transesophageal echocardiography views in the perioperative setting. Anesth Analg 2013; 116: 1231-6. PMID: 10.1213/ANE.0b013e31828cbaca. PMID: 23558842.
crossref pmid
7. Jaber WA, Prior DL, Thamilarasan M, Grimm RA, Thomas JD, Klein AL, et al. Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study. Am Heart J 2000; 140: 150-6. PMID: 10.1067/mhj.2000.106648. PMID: 10874278.
crossref pmid
8. Mügge A, Daniel WG, Haverich A, Lichtlen PR. Diagnosis of noninfective cardiac mass lesions by two-dimensional echocardiography. Comparison of the transthoracic and transesophageal approaches. Circulation 1991; 83: 70-8. PMID: 10.1161/01.CIR.83.1.70. PMID: 1984900.

9. Manning WJ, Weintraub RM, Waksmonski CA, Haering JM, Rooney PS, Maslow AD, et al. Accuracy of transesophageal echocardiography for identifying left atrial thrombi. A prospective, intraoperative study. Ann Intern Med 1995; 123: 817-22. PMID: 10.7326/0003-4819-123-11-199512010-00001. PMID: 7486462.

10. European Association for Cardio-Thoracic Surgery. Camm AJ, Kirchhof P, Lip GY, Schotten U, Savelieva I, et al. Guidelines for the management of atrial fibrillation: the Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC). Eur Heart J 2010; 31: 2369-429. PMID: 10.1093/eurheartj/ehq278. PMID: 20802247.
crossref pmid pdf
11. Grimm RA, Stewart WJ, Black IW, Thomas JD, Klein AL. Should all patients undergo transesophageal echocardiography before electrical cardioversion of atrial fibrillation? J Am Coll Cardiol 1994; 23: 533-41. PMID: 10.1016/0735-1097(94)90443-X.
crossref pmid
12. Oneglia C, Rusconi C. Left atrial appendage thrombus as a source of peripheral embolism: TEE evidence of direct relationship. Echocardiography 2001; 18: 389-90. PMID: 10.1046/j.1540-8175.2001.00389.x. PMID: 11466150.
crossref pmid
13. Oral H, Chugh A, Ozaydin M, Good E, Fortino J, Sankaran S, et al. Risk of thromboembolic events after percutaneous left atrial radiofrequency ablation of atrial fibrillation. Circulation 2006; 114: 759-65. PMID: 10.1161/CIRCULATIONAHA.106.641225. PMID: 16908760.
crossref pmid
14. Ando T, Abe H, Ro D. A case of embolism due to a floating thrombus migrating from the left atrial appendage to the ostium of the celiac artery. Ann Vasc Dis 2012; 5: 229-32. PMID: 10.3400/ PMID: 23555518. PMID: PMC3595879.
crossref pmid pmc
15. Nishikii-Tachibana M, Murakoshi N, Seo Y, Xu D, Yamamoto M, Ishizu T, et al. Prevalence and clinical determinants of left atrial appendage thrombus in patients with atrial fibrillation before pulmonary vein isolation. Am J Cardiol 2015; 116: 1368-73. PMID: 10.1016/j.amjcard.2015.07.055. PMID: 26358509.
crossref pmid

Article category

Browse all articles >


Browse all articles >

Editorial Office
101-3503, Lotte Castle President, 109 Mapo-daero, Mapo-gu, Seoul 04146, Korea
Tel: +82-2-792-5128    Fax: +82-2-792-4089    E-mail:                

Copyright © 2024 by Korean Society of Anesthesiologists.

Developed in M2PI

Close layer
prev next