ASYMPTOMATIC MICROEMBOLISM IN PATIENTS WITH LONG-TERM VENTRICULAR ASSIST SUPPORT

The incidence of clinically significant thromboembolic events is repor ted to be as high as 25% in patients with left ventricular assist devi ces (LVAD). Clinically detectable neurologic deficits resulting from t hromboembolic events are reported to occur at a frequency of 0.0056% p er patient-month with the Thermo Cardiosystems Heartmate 1000 (Woburn, MA) intraperitoneal LVAD (TCI). To date, the occurrence of asymptomat ic cerebral microemboli in patients with this device has not been char acterized. Transcranial doppler (TCD) monitorings were used for evalua tion of the incidence of cerebral microembolism in 14 patients with th e TCI LVAD. Studies were performed after LVAD support ranging from 7 t o 305 days. Overall, 35 studies were obtained from the left middle cer ebral artery for a duration of 30 minutes per study and the number of high intensity transient signals (HITS) were recorded. In one patient with a fatal stroke, an average of 0.86 HITS per study period (0.03/mi n) was observed. In 13 patients without any symptoms, an average of 0. 46 HITS per study (0.016/min) was observed. Overall, no HITS were dete rmined in 74% of the studies. Although the clinical significance or th e nature of these microemboli is unknown, the data support that microe mbolism with the TCI LVAD is a rare event despite absence of anticoagu lation. Long-term detailed neurocognitive testing and hematologic asse ssment is needed to establish the clinical relevance of these microemb oli in patients with detected signals.