Background and aims of the study: This study was performed to evaluate the time course of intracranial high-intensity transient signals (HITS) in patients undergoing elective heart valve replacement.
Methods: Thirty-three patients were enrolled in this study. The examination protocol included serial (before and at one, five, 90 and 180 days after surgery) monitoring sessions with transcranial Doppler and detailed neurological examination. Monitoring was performed bilaterally over the middle cerebral arteries for one hour per session using 2 MHz probes. Microembolic signals were recognized according to standard criteria and stored on a computer for later evaluation.
Results: HITS prevalence increased from 3% preoperatively to 41% on the first postoperative day and remained unchanged during the postoperative period. No influence of the intensity of anticoagulation or valve type on HITS counts was evident. Unilateral monitoring provided adequate results in 83.9% of cases.
Conclusions: The causative role of the valve implant in the pathogenesis of HITS appears certain, since their prevalence dramatically increases following valve implantation. Valve type, duration of valve implant or intensity of anticoagulation did not influence HITS counts. Bilateral monitoring is warranted for accurate evaluation of HITS counts in this patient group.