P708 Multimodality imaging of catheter-related right atrial thrombus: a case report
Authors: Skofic N , Dolinsek A , Prokselj K 
Published: January 2020

Abstract

INTRODUCTION
Catheter-related right atrial thrombosis (CRAT) is potentially life-threatening complication of long-term indwelling central venous catheters (CVC), which are used extensively in various patients. Reported incidence of CRAT is variable (2-62%) and probably underestimated due to predominantly asymptomatic course and lack of routine screening. Main pathogenic mechanisms that promote CRAT include mechanical and chemical injury of atrial endocardium by the catheter and infused drugs, stasis of blood and hypercoaguability. Differential diagnosis between thrombus and other intracardiac masses, especially myxoma, is sometimes very difficult and requires multimodality imaging studies.

CASE PRESENTATION
62-years old patient after chemotherapy of lymphoma, in remission, with subcutaneous CVC inserted in right subclavian vein, which was used as chemotherapy port several years ago, was sent to emergency department because right atrial mass was found on elective outpatient transthoracic echocardiography (TTE). Urgent computed tomography (CT) was performed and showed well defined, 1.8 x 2.0 cm large, low attenuating mass with some calcifications. Several features were primarily suggestive of myxoma, however differentiation from thrombus was not possible. Patient was admitted to hospital, where transesophageal echocardiography (TEE) confirmed the presence of heterogenous mass attached to right atrial free wall with tumor-like movement. Mobile catheter tip was nearby and touching the mass irregularly. Although in addition to CT also some echocardiographic characteristics were more consistent with myxoma, there was still high clinical suspicion of CRAT due to multiple risk factors for thrombosis. Cardiac magnetic resonance imaging (MRI) using cine sequence was performed for further evaluation and revealed mobile, homogeneously low-signal intensity mass that remained hypointense on contrast-enhanced sequences (first pass perfusion and late gadolinium enhancement), which led to final diagnosis of thrombus.

CONCLUSION
CRAT should be suspected and anticipated in all, also asymptomatic patients with long-term indwelling CVC (e.g. for chemotherapy, parenteral nutrition, hemodialysis..), majority of whom have additional multiple risk factors for thrombosis. Routine screening for CRAT can provide early diagnosis and treatment and should be considered especially in high-risk patients in order to prevent potentially severe complications. Although echocardiography is the modality of choice for screening, further imaging modalities, e.g. CT and MRI are often required to differentiate thrombus from myxoma or other cardiac masses. Our case demonstrates difficult differential diagnosis of right atrial mass in an asymptomatic patient with a long-term indwelling chemotherapy port, in whom multimodality imaging studies were performed, but only MRI with contrast-enhanced sequences providing superior tissue characterization, could differentiate between CRAT and myxoma.
Abstract P708 Figure. Multimodality imaging of atrial thrombus