Detection of Left Ventricular Apical Thrombus With Three-Dimensional Transesophageal Echocardiography

Case Presentation

A 50-year-old man with a history of coronary artery disease, multiple myocardial infarctions, and an apical aneurysm of the left ventricle, presented with persistent ventricular tachycardia for endocardial ablation. He underwent dual chamber implantable cardioverter-defibrillator (ICD) placement in 2004, at which time he was diagnosed with a thrombus in his left ventricular apex. The patient was referred by the electrophysiologist for left ventricular aneurysmectomy to resect the focus of his arrhythmia, since repeated ablations were unsuccessful. On this admission, the patient underwent repeated transthoracic echocardiograms during which the apical thrombus was not detected and also could not be ruled out, by both two-dimensional (2D) and 3D transthoracic echocardiography (TTE; Video 1).

The patient was taken to the operating room. External defibrillator pads were placed as the internal defibrillator was turned off. Following arterial line placement general anesthesia was induced. Transesophageal echocardiography (TEE) was performed using a 3D TEE probe (X7-2t probe, Philips, Andover, MA). Two-dimensional TEE and real-time 3D TEE were used to evaluate the left ventricular aneurysm. Initial 2D TEE revealed a dyskinetic left ventricular apex, with a suspected apical clot based on a double layer apical wall (Video 2, panel A). Subsequently, 3D images were obtained, including both live 3D imaging, along with the 3D full volume imaging. The full volume images were further optimized by cropping the anterior wall, which further supported a double layer apical wall (Figure 1 and Video 2, panel B). After multiple offline image manipulations of the left ventricle from multiple directions, an apical thrombus was visible under the thin apical wall (Video 2, panel C). A patent Foramen ovale was excluded both with color Doppler examination and with bubble study. Subsequently, the patient was placed on cardiopulmonary bypass without aortic cross clamp. The aneurysm was carefully opened and a circular apical clot was removed (Figure 2). Following aneurysm resection and ventricular restoration, the patient was successfully weaned off bypass with minimal inotropic support. He was extubated the next day without any neurological sequelae.

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Figure 1.

Three-dimensional live 4-chamber view, showing a double layer left ventricular apical wall, representing the apical thrombus

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Figure 2.

Organized thrombus removed from the left ventricular apex during surgery

Discussion

Left ventricular thrombus formation is a known complication in patients with acute anterior myocardial infarction, subsequent low ejection fraction, left ventricular aneurysm formation, and in those with dilated cardiomyopathy. Perioperative recognition of the left ventricular thrombus is important as it can affect surgical planning either by postponing the surgery and instituting anticoagulation, or in the case of emergent surgery, by performing a left ventricular thrombectomy thus avoiding embolization and catastrophic patient outcome.

Both 2D TTE and 2D TEE have been commonly used for clinical identification of left ventricular thrombi. ¹ However, it has been estimated that 10% to 15% of routine echocardiography studies have incomplete endocardial resolution, thus echocardiography has the potential to miss ventricular thrombus. Contrast echocardiography has been demonstrated to significantly improve thrombus detection through cavity opacification, but it is not routinely used yet in the ambulatory and operating room settings. ² Key characteristics in diagnosis of ventricular thrombus include ³

Three-dimensional echocardiography has been shown to be potentially superior to 2D techniques assessing intracardiac masses as it acquires a pyramidal volume of information that can be visualized from different angles.^4,5 Because of the close proximity of the transducer to the left ventricular apex, TTE is generally considered to be superior to TEE for thrombus detection. However, TEE has been shown to be a useful complementary approach because of the lack of reflection artifacts and no near-field resolution limitations. ⁶ As an addition to the diagnostic sequence of the standard 2D TEE examination, from the 4-chamber view, the system should be switched to 3D modality enabling the full volume or live 3D left ventricular chamber acquisition. Acquired images can be analyzed live or offline for better accuracy and cropping.

Conclusions

Neither 2D TTE nor 3D TTE diagnosed the thrombus in this patient, but real-time 3D TEE was able to visualize the presence of a left ventricular apical thrombus. This case presents an example that real-time 3D TEE can be a complementary technique of detecting left ventricular masses compared with noncontrast 2D TTE or 3D TTE and if readily available, should be considered an important adjunct of left ventricular assessment in high-risk patients.