Lindner A, Georgiadis D, Lühmann A, Stephan M, Preiss M, Zerkowski H R, Zierz S
Department of Neurology, Martin-Luther-University Halle-Wittenberg, Germany.
J Heart Valve Dis. 1997 Sep;6(5):527-30.
This study was performed to evaluate the time course of intracranial high-intensity transient signals (HITS) in patients undergoing elective heart valve replacement.
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.
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.
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.
本研究旨在评估择期心脏瓣膜置换患者颅内高强度瞬态信号（HITS）的时间进程。
33例患者纳入本研究。检查方案包括（术前及术后1天、5天、90天和180天）经颅多普勒系列监测及详细的神经学检查。每次监测使用2MHz探头，双侧大脑中动脉各监测1小时。微栓子信号依据标准标准识别，并存储于计算机以便后续评估。
HITS发生率从术前的3%增至术后第1天的41%，且在术后期间保持不变。抗凝强度或瓣膜类型对HITS计数无明显影响。83.9%的病例单侧监测即可提供足够结果。
瓣膜植入在HITS发病机制中的致病作用似乎确凿，因为瓣膜植入后其发生率显著增加。瓣膜类型、瓣膜植入时间或抗凝强度不影响HITS计数。对于该患者群体，双侧监测对于准确评估HITS计数是必要的。
