Elevated levels of procoagulant microparticles in a patient with myocardial infarction, antiphospholipid antibodies and multifocal cardiac thrombosis

Abstract

Circulating procoagulant microparticles (MP) are pathogenic markers of enhanced coagulability associated to a variety of disorders and released from stimulated vascular cells. When derived from endothelial cells, MP were found characteristic of thrombotic propensity in primary antiphospholipid syndrome (APS). The prothrombotic status of a patient with antiphospholipid antibodies (APL), a past history of mesenteric vein thrombosis and presenting myocardial infarction and extensive intracardiac thrombosis was examined by measurement of circulating procoagulant MP. MP of platelet and endothelial origins were highly elevated with respect to values detectable in patients with myocardial infarction and no history of APS (6- and 3-fold elevation, respectively) or in healthy volunteers (13- and 25-fold elevation, respectively). In this particular patient, with moderate APL titer, a drastic release of procoagulant MP could have contributed to thrombus growth and the development of extensive intracardiac thrombosis.

Figure 1

At patient admission, left coronary angiogram revealed thrombotic obstruction of left anterior descending artery (A). Large thrombus in the right auricle emerging through tricuspid valve within right ventricle (B) and apical thrombus complicating anterior aneurysm (C) detected by computer tomography scan, performed the next day. Large thrombus emerging from superiour vena cava and prolabing in the right auricle, evidenced by Trans-oesophagial echocardiography (D). Extensive thrombus emerging from superiour vena cava within right auricle, evidenced by magnetic resonance imaging (E).