Abundance of microembolic signals detected by transcranial Doppler ultrasound in a patient with Eisenmenger's syndrome

Background: Clinically silent circulating microemboli can be detected by tr anscranial Doppler sonography. Case Description: We report the case of a 45 -year-old man with congenital cyanotic heart disease, elevated haematocrit, low platelet count and decreased protein C and protein S activity. Before and following several haemodilutions, we performed 5 1-hour transcranial Do ppler recordings from one or both middle cerebral arteries (MCAs) on differ ent days. The number of microembolic signals per hour varied from 54 to 134 . During the bilateral recording, the microemboli occurred on both sides (5 5 in the right and 45 in the left MCA, respectively). There was no relation to red blood cell count, platelet count, the spontaneously lowered prothro mbin time or the spontaneously prolonged activated partial thromboplastin t ime. Conclusions: The origin of the large number of microembolic signals fo und in this patient remains unclear, but may be presumed in the intra-abdom inal or crural venous system.