肝移植术后肝动脉狭窄的多普勒超声最佳临界值确定及对小慢波患者临床决策作用的研究

摘要

Objective To analyze the optimal threshold of Doppler ultrasonography(DUS)in the diagnosis of hepatic artery stenosis(HAS)after liver transplantation and propose the diagnostic criteria of CT angiography(CTA) or digital subtraction angiography(DSA)for patients with tardus parvus waveform(TPW)in combination with liver dysfunction. Methods Clinical data of 171 patients undergoing liver transplantation, postoperative conventional DUS, liver function test, CTA or DSA were collected. The optimal threshold of resistance index(RI)and systolic acceleration time (SAT)for the diagnosis of HAS were determined by multi-level likelihood ratio(MLR). Different diagnostic criteria were established and the diagnostic efficacy was statistical y compared. Positive TPW was defined as the diagnostic criterion with low confidence, positive TPW+liver dysfunction as the moderate confidences, and positive TPW+liver dysfunction or positive TPW+optimal threshold as the high confidence. Results MLR revealed that RI<0.4 and SAT>0.12 s were the optimal threshold for the diagnosis of HAS. The specificity of diagnostic criteria with moderate and high confidence was significantly higher compared with that of the low confidence(P<0.05). Moreover, the false-positive rate was significantly decreased(P<0.05). The sensitivity of diagnostic criterion with moderate confidence was significantly lower than those of low and high confidence(both P<0.05), whereas the sensitivity did not significantly differ between the diagnostic criteria with low and high confidence(P>0.05). Conclusions For patients with positive TPW detected by DUS after liver transplantation, the optimal threshold of diagnostic criteria combined with liver dysfunction contribute to appropriate clinical decision-making for clinicians.%目的：分析多普勒超声（DUS）诊断肝移植术后肝动脉狭窄（HAS）的最佳临界值，并结合肝功能异常，提出小慢波（TPW）患者接受CT血管造影（CTA）或数字血管造影（DSA）检查的诊断标准。方法收集171例行肝移植术并在术后常规复查DUS、肝功能检查并行CTA或DSA检查确诊患者的临床资料。采用多水平似然比（MLR）确定肝动脉阻力指数（RI）及收缩期加速时间（SAT）诊断HAS的最佳临界值。建立不同诊断标准（低信心类为TPW阳性，中等信心类为TPW阳性+肝功能异常；高信心类为TPW阳性+肝功能异常或TPW阳性+最佳临界值）并比较其诊断效能。结果 MLR显示诊断HAS的最佳临界值为RI<0.4，SAT>0.12 s。中等信心类及高信心类诊断标准的特异度明显高于低信心类（P<0.05），且假阳性率明显降低（P<0.05）。另外，中等信心类诊断标准的灵敏度明显低于低信心类及高信心类（P<0.05），而低信心类与高信心类诊断标准间的灵敏度差异无统计学意义（P>0.05）。结论对于肝移植术后DUS检查显示TPW阳性的患者，结合肝功能异常及最佳临界值这一诊断标准可帮助临床医师对其作出适当的临床决策。