Use of Transesophageal Echocardiography in the Evaluation and Surgical Treatment of a Patient with an Aneurysmal Interatrial Septum and an Intracardiac Thrombus Traversing a Patent Foramen Ovale

Abstract

A 77-yr-old women presented to an outside hospital complaining of shortness of breath and transient diploplia. A transthoracic echocardiogram revealed an intracardiac mass and, due to the high risk of systemic embolization, she was transferred to our institution for emergency surgical removal. In the operating room, after induction of general anesthesia, transesophageal echocardiography (TEE) was performed, revealing a large serpentine mass in the right atrium extending across an aneurysmal interatrial septum into the left atrium through a patent foramen ovale (PFO). The end sections of this horseshoe-shaped mass repeatedly descended into both ventricles during diastole and then flipped back into the atria before atrioventricular valve closure and ventricular systole. (Figs. 1 and 2, Video clips 1–4; please see video loop at www. anesthesia-analgesia.org). TEE was used to guide placement of a left subclavian central line and bicaval cannulation. During placement of these devices, a bicaval view revealed that neither the central line wire nor the venous cannulae entered the right atrium and interfered with the thrombus. The proximal pulmonary arteries were examined in the midesophageal ascending aortic short axis view, and no thrombus was seen. The thrombus was removed and the PFO was closed. Postoperatively, the patient was neurologically intact and was discharged 7 days after admission. Of interest, the patient’s symptom of dyspnea was due to distal pulmonary artery emboli (unseen on TEE) from deep venous thromboses. We think the pulmonary emboli increased right atrial pressure and thereby facilitated right-to-left flow and “trapping” of the large thrombus in the PFO. Aneurysmal interatrial septums occur with a prevalence of 1%–2.2% and are associated with a PFO in 50%–89% of patients. Patients with an aneurysmal interatrial septum and a PFO constitute a high-risk group with a risk of recurrent paradoxical cerebral embolus 3–5 times more than patients with a PFO alone. An aneurysmal interatrial septum is a thin, highly compliant sail-like septum that moves back and forth between the atria with increased excursion compared with a normal septum. The exact amount of excursion that constitutes an aneurysmal interatrial septum varies between 6 and 15 mm, but most authors use a cutoff of 10 mm of excursion. Motion mode (M-mode) can be helpful when measuring excursion, which should be measured from the maximal point of the bulging to an imaginary line connecting the nonaneurysmal segments of the septum primum at the base of the aneurysm. Aneurysmal interatrial septums may contribute to paradoxical emboli by three mechanisms: