HIGH-INCIDENCE OF LEFT ATRIAL THROMBUS DETECTED BY TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN HEART-TRANSPLANT RECIPIENTS

The aim of the study was the detection of spontaneous echo contrast (SEC) and left atrial thrombus by transoesophageal echocardiography (TEE) in patients who had undergone orthotopic heart transplantation. TEE was prospectively performed in 64 heart transplant recipients (53 males, 11 females, mean age 51 years). Since surgery (mean time: 31 months), all heart transplant recipients had received either aspirin (39), or dipyridamole (22), or both (3). Despite the antiplatelet treatment, an acute arterial embolism (two strokes, one popliteal and one mesenteric ischaemial) occurred in four patients who subsequently received an oral anticoagulant therapy. TEE was performed with a biplane high-frequency transducer after lidocaine pharyngeal anaesthesia, midazolam intravenous injection and antibiotic prophylaxis. Mean ejection action was 63 +/- 10%. None had evidence of rejection at endomyocardial biopsy performed on the same day as TEE and analysed in a blinded fashion. All were in sinus rhythm. Left atrial SEC was found in 35 patients (55%) and was associated with left atrial thrombus in 18 patients (28%). These thrombi were localized in the donor left atrial appendage in 10 cases on the posterior wall of the left atrium in six cases, on the donor part of inter-atrial septum in one case and on the suture line in one case. They were not detected by transthoracic echocardiography (TTE). When compared with patients without thrombus, no difference was found concerning left atrial size, left ventricular ejection fraction, pulmonary artery pressure and number of previous episodes of rejection. However, cardiac index was significantly lower in patients with left atrial thrombus. The four patients with an arterial embolism had left atrial thrombus associated with spontaneous echo contrast. This study demonstrated the high occurrence of thrombus formation in the enlarged left atrium of cardiac allograft and emphasized the importance of TEE in the follow-up of heart transplant recipients. Left atrial SEC is a common finding suggesting further prospective TEE studies are needed to determine its prognostic significance in heart transplant patients. These results indicate that a decision is required regarding preventive anticoagulant therapy in heart transplant recipients having SEC or left atrial thrombus or an alternative surgical approach may be needed, such as caval anastomosis.