TIME-COURSE OF HIGH-INTENSITY TRANSIENT SIGNALS IN PATIENTS UNDERGOING ELECTIVE HEART-VALVE REPLACEMENT - A PROSPECTIVE-STUDY

Background and aims of the study: This study was performed to evaluate the time course of intracranial high-intensity transient signals (HIT S) in patients undergoing elective heart valve replacement. Methods: T hirty-three patients were enrolled in this study. The examination prot ocol included serial (before and at one, five, 90 and 180 days after s urgery) monitoring sessions with transcranial Doppler and detailed neu rological examination. Monitoring was performed bilaterally over the m iddle cerebral arteries for one hour per session using 2 MHz probes. M icroembolic signals were recognized according to standard criteria and stored on a computer for later evaluation. Results: HITS prevalence i ncreased from 3% preoperatively to 41% on the first postoperative day and remained unchanged during the postoperative period. No influence o f the intensity of anticoagulation or valve type on HITS counts was ev ident. Unilateral monitoring provided adequate results in 83.9% of cas es. Conclusions: The causative role of the valve implant in the pathog enesis of HITS appears certain, since their prevalence dramatically in creases following valve implantation. Valve type, duration of valve im plant or intensity of anticoagulation did not influence HITS counts. B ilateral monitoring is warranted for accurate evaluation of HITS count s in this patient group.