Editor:

Transoesophageal echocardiography (TOE) is now established as an important diagnostic tool in the operating theatre and the intensive care unit (ICU). The surgical management of pulmonary and intracardiac thromboembolism, particularly when complicated by impending paradoxical embolism, presents the perioperative echocardiographer with the opportunity to influence surgical decision making and to potentially improve patient outcome [1]. We report a case demonstrating the use of TOE in both the diagnosis and the intraoperative management of a patient with major pulmonary thromboembolism and thrombus straddling a patent foramen ovale (PFO).

A 47-yr-old female presented to hospital complaining of acute dyspnoea and palpitations. She had been less mobile in the previous 2 weeks because of an ankle injury. Her past medical history included a benign pituitary neoplasm and sub-fertility. She did not take any medication. Thoracic computed tomography (CT) showed bilateral pulmonary thromboemboli and suspected intracardiac thrombus. Anticoagulation was commenced and the patient was immediately transferred to the regional cardiothoracic surgery centre. On admission to the ICU, physical examination revealed pulse 120 beats min⁻¹, blood pressure 110/70 mmHg, oxygen saturation on room air 94%, respiratory rate 22 breaths min⁻¹ and the presence of a lower abdominal mass. There was no evidence of lower limb venous thrombosis.

Transthoracic echocardiography (TTE) provided evidence of a mobile mass in the right atrium but adequate imaging of the left atrium was not obtained. TOE was subsequently performed, in close collaboration between the anaesthesia and cardiology teams, under general anaesthesia in the ICU. A large serpiginous mass, measuring 7 cm long and 1 cm wide, was identified originating in the right atrium and traversing the intra-atrial septum through a PFO into the left atrium. The right ventricle was dilated, global function was impaired, functional tricuspid regurgitation was present and there was evidence of pulmonary hypertension. No central pulmonary artery emboli were visible. The patient remained sedated and mechanically ventilated following TOE and underwent CT of the thorax, abdomen and pelvis. This confirmed extensive thrombus in the right and left pulmonary arteries, and also revealed a large uterine tumour with significant pelvic venous compression and thrombosis.

The patient proceeded to emergency surgery to prevent impending paradoxical systemic thromboembolism. Cardiopulmonary bypass (CPB) was established following which intracardiac thrombectomy, pulmonary thromboembolectomy and closure of PFO were performed. After separation from CPB, a comprehensive intraoperative TOE examination confirmed the absence of residual intracardiac thrombus and complete closure of the PFO. Inferior vena cava filter insertion and hysterectomy were also performed. Following an uneventful postoperative course, she was discharged from hospital on oral anticoagulation therapy.

Cases of thrombus entrapment in a PFO are rare but may have devastating consequences. A PFO straddling thrombus may embolize into the right atrium causing pulmonary embolism or into the left atrium causing paradoxical systemic embolism. Erkut and colleagues [Reference Erkut, Kocak, Becit and Senocak2] reviewed 46 reported cases and suggest that this unusual occurrence is increasingly being recognized because of the widespread use of TOE. The clinical presentation is variable: 45.6% of cases presented with clinical features of pulmonary embolism without evidence of paradoxical embolism (like our patient), 28.2% presented with both pulmonary and paradoxical embolism and 12.7% presented with paradoxical embolism only. Chartier and colleagues [Reference Chartier, Bera and Delomez3], in their case series of patients with floating right heart thrombi, emphasize the importance of echocardiography as the key diagnostic investigation: both transthoracic and transoesophageal modalities may be used in conjunction to confirm the diagnosis. The likelihood of unsatisfactory imaging of the left atrium using TTE underlines the superiority of TOE in these cases. Aboyans and colleagues [Reference Aboyans, Lacroix, Ostyn, Cornu and Lasker4] reported an overall early mortality of 21% in their review of known cases. Immediate treatment is warranted but the optimal management is controversial: therapeutic options include anticoagulation, thrombolysis or surgical management. Fragmentation of the right or left atrial components of the thrombus followed by pulmonary or systemic embolization is a theoretical risk of thrombolytic therapy. Medical therapy has also been associated with recurrent complications. Therefore, intracardiac thrombectomy and closure of the PFO has been recommended for the treatment of thrombus entrapment. Intraoperative TOE can accurately identify thrombus in the PFO [Reference Perruchoud, Blanc, Ruchat, Chassot, Brenn and Spahn5], confirm its successful removal and assess closure of the defect [Reference Plotkin, Fox, Aranki and Collard6].

We conclude that TOE is useful in the preoperative diagnosis of pulmonary and intracardiac thrombi in the ICU and essential to assist intraoperative decision making in the surgical management of these patients in the operating theatre.