Right ventricular thrombi in primary antiphospholipid syndrome

Over a period of several months a 33-year-old man had recurrent pulmonary emboli. No thromboses could be demonstrated in the peripheral venous system. Transoesophageal echocardiography showed two spherical space-occupying structures in the right ventricle which were removed operatively under the suspected diagnosis of multilobular myxomas. However, their histological examination revealed pure thrombi that had grown by apposition. This unusual findings of right-ventricular thrombi could not be explained pre- and intraoperatively by any local thrombi-favouring changes in the right heart. Tests of clotting mechanisms demonstrated lupus anticoagulant (kaolin-clotting-time mixture test: LA index 21.7 [normal: < 15]), as well as an increased IgG cardiolipin antibody concentration of 19.3 U/l). As no underlying disease was discovered, the diagnosis was by definition primary antiphospholipid syndrome. No further thrombo-embolism has occurred during continuing oral anticoagulation with phenprocoumon.