Sources of Variability in the Detection of Cerebral Emboli with Transcranial Doppler During Cardiac Surgery

OBJECTIVE: The application of intensity thresholds for embolus detection with transcranial Doppler (TCD) can exclude from analysis an unrecognized proportion of high-intensity transient signals (HITS))whose intensities are below the threshold. The lack of consistent threshold criteria between clinical trials may explain part of the discrepancy in the reported HITS counts. We investigated the effect of choosing different thresholds on the sensitivity and specificity of detecting HITS during cardiopulmonary bypass (CPB). METHODS: Two observers independently analyzed TCD recordings from 8 patients under CPB. Doppler signals were classified as true HITS, equivocal HITS, artifacts, and Doppler speckles according to preestablished criteria. The relative intensity of Doppler signals was measured by two different methods (TCD software vs manual). Receiver Operating Characteristic curves determined the optimal threshold for each of the two intensity methods. RESULTS: Reviewers achieved agreement in 96% of 2190 Doppler signals (kappa = 0.90). Relative intensities calculated with the TCD-software method were 3 dB (95% CI: 3.0-3.4) higher than the manual method. The optimal threshold was found at 10 dB (sensitivity: 99%; specificity: 90.8%) with the software method and at 7 dB with the manual method (sensitivity: 96%; specificity: 83%). The use of an intensity threshold 2 dB higher than the optimal increased the rejection of true HITS by 8% and 14%, respectively. CONCLUSIONS: Using intensity thresholds higher than the optimal for embolus detection decreases HITS counts. Choosing a threshold depends on the type of method used for measuring the signal intensity. Uniform threshold criteria and comparative studies between different Doppler devices are necessary for making clinical trials more comparable.     

颅内动脉瘤的血管内栓塞治疗

目的探讨应用电解可脱性弹簧圈(GDC)栓塞治疗颅内动脉瘤的临床效果。方法2002年6月-2004年6月我们采用GDC栓塞颅内动脉瘤126例(其中4例有2个动脉瘤,共130个)。前交通动脉瘤42个,后交通动脉瘤53个,颈内动脉瘤6个,大脑中动脉瘤10个,大脑后动脉瘤8个,大脑前动脉瘤6个,小脑后下动脉瘤2个;基底动脉瘤3个。按Hunt-Hess分级:Ⅰ级38例,Ⅱ级54例,Ⅲ级23例,Ⅳ级11例。必要时辅以篮筐技术、重塑技术、支架技术、双微导管或连环技术、蚕食技术。结果成功栓塞126例动脉瘤,其中103例为100%栓塞,21例为95%,2例为90%。12例在栓塞后6~18个月进行造影随访,所栓塞动脉瘤均未见复发征象。结论GDC栓塞颅内动脉瘤是安全、有效和微创的治疗手段。联合运用多种栓塞技术有助于减少术后并发症,提高治愈率。     

三磷酸腺苷结合盒运转体A1与颈动脉粥样硬化斑块的关系

目的 探讨三磷酸腺苷结合盒运转体A1(ATP binding cassette transporter A1,ABCA1)在人颈动脉粥样硬化斑块中的表达变化及作用机制.方法 收集24例人颈动脉粥样硬化斑块标本和10例肠系膜动脉标本(对照组),采用RT-PCR测定ABCA1 mRNA和视黄酸X受体α(RXRα)mRNA表达水平,并采用Western Blot检测ABCA1及RXRα的蛋白表达水平.24例人颈动脉粥样硬化斑块标本按病理分级,比较病理组织为Ⅲ级和Ⅰ级动脉粥样硬化组织间ABCA1 mRNA、RXRαmRNA表达水平及蛋白表达水平.结果 颈动脉粥样硬化斑块组的ABCA1 mRNA(0.79±0.04)和RXRα mRNA(0.73±0.04)表达与对照组相比上调,差异有统计学意义(P＜0.05);ABCA1 mRNA与RXRα mRNA增加水平相关(P＜0.05);颈动脉粥样硬化斑块的ABCA1蛋白表达(0.22±0.03)下调水平与对照组(0.53±0.03)相比差异有统计学意义(P＜0.05);Ⅲ级和Ⅰ级动脉硬化斑块ABCA1mRNA、RXRα mRNA及蛋白表达水平差异有统计学意义(P＜0.05).结论 ABCA1及RXRα蛋白表达水平下调可能是进展性动脉粥样硬化损害的关键因素.     

异丙酚和异氟醚对非体外循环搭桥术患者围术期细胞因子的影响

目的:研究异丙酚和异氟醚对非体外循环搭桥术患者围术期炎性与抗炎性细胞因子平衡的影响。方法:择期非体外循环搭桥患者50例,随机分为2组。异丙酚组微量泵输入剂量为4～6mg·kg-·1h-1,异氟醚组吸入浓度为1%～1.5%。检测诱导前、打开心包、旁路血管开放30min,术后2h、24h血清白细胞介素6(IL-6)、白细胞介素10(IL-10)和肿瘤坏死因子α(TNF-α)的浓度。结果:2组患者旁路血管开放后IL-6浓度较术前升高(P<0.01),术后2h达高峰;术后2h异氟醚组高于异丙酚组(P<0.05)。IL-10浓度变化趋势与IL-6相似,旁路血管开放后、术后2h和24h异丙酚组高于异氟醚组(P<0.05)。2组患者TNF-α水平均无显著变化。结论:异丙酚麻醉促进IL-10的产生,抑制IL-6的产生,控制术中应激反应异丙酚优于异氟醚。     

2 121例老年急性冠脉综合征患者血清脂类浓度的分析

目的分析60岁以上老年人血清脂类水平的参考值,并探讨急性冠脉综合征与血脂指标的相关性.方法将3 766例健康成人分为≤60岁和＞60岁的两个年龄段,采用生物化学的方法测量他们的血脂水平,找出60岁以上老年人的脂类参考值.同时分析2 121例老年急性冠脉综合征病人的脂类指标.结果 60岁以上老年人血脂参考值为:TC 4.65±1.96×1.05mmol/L;TG 1.02±1.96×0.45mmol/L;HDL-C 1.47±1.96×0.40mmol/L;LDL-C 2.98±1.96×0.56mmol/L;ApoA1 1.32±1.96×0.25g/L;ApoB 0.99±1.96×0.35g/L,并且急性心肌梗死和不稳定性心绞痛病人血清脂类各项指标之间没有显著性差异.结论血清LDL-C/HDL-C＞5和TG ≥1.9mmol/L这两项联合指标比其他单独指标与老年人急性冠脉综合征关系更密切.     

便携式多普勒血管探测仪在皮瓣移植中的应用

目的 :研究皮瓣移植前简单、可靠的血管探测的方法。方法 :在皮瓣移植前 ,以 HADECO ES-1 0 0 0 SPM多普勒血管探测仪对皮瓣血管蒂及皮动脉进行探测 ,与术中皮动脉探查结果进行比较 ,考察术前血管探测的准确性和意义。结果 :皮瓣血管蒂及皮动脉术前探测与术中探查结果完全一致。结论 :便携式血管多普勒仪是皮瓣移植前 ,简单、可靠的血管探测的仪器 ,根据探测结果进行皮瓣设计 ,有效地降低了手术失败的风险     

血管内皮细胞受损后急性低氧性肺血管收缩反应减弱

为了探明血管内皮细胞在急性低无性肺动脉高压中的作用进行了本研究。雄性ＳＤ大鼠经２０％乌拉坦麻醉，气管插管，呼吸机通气。动物分为两组：单纯低氧组（ｎ＝１０只）吸１０．５％低氧混合气体５分钟；另一组为肺损伤低无组（ｎ＝７只），ＡＮＴＵｌｍｇ／ｋｇ缓慢注入肺动脉内，再吸入１０．５％低氧混合气体。实验结果表明：大鼠吸入低氧混合气体后肺动脉平均压ＰＰａ）增加２０．４±６．５％，而肺损伤后再吸入低氧气体，ＰＰａ仅增加８．７±３．８％，显著低于单纯低氧组（Ｐ＜０．０１）．结果提示：血管内皮细胞受损后急性低氧性肺血管收缩反应明显减弱。     

慢性低氧大鼠肺动脉内皮素mRNA的表达及定位

目的：探讨慢性低氧大鼠肺动脉内皮素－1基因表达及分布。方法：采用生物素标记cRNA探针，对Wistar大鼠肺动脉进行原位杂交。结果：低氧1周组及低氧2周组大鼠大部分肺动脉内皮细胞ET－1mRNA表达呈阳性信号，而对照组大鼠仅极少数阳性信号（P＜0．01）；低氧1周组大鼠部分显示强阳性信号。低氧1周组及低氧2周组大鼠部分肺动脉平滑肌细胞呈现ET-1mRNA表达阳性信号，而对照组大鼠则无阳性信号表达（P＜0．01及0．05）。结论：慢性低氧对大鼠肺动脉ET－1分泌的影响是在基因转录水平进行，且主要细胞定位在肺动脉内皮细胞，此外还包括肺动脉平滑肌细胞。     

椎动脉型颈椎病的影像学诊断

本文描述了椎动脉型颈椎病的概念及发病机制 ,并对该病的各种影像学检查的主要表现及优缺点进行了综述。