Tessitore Nicola, Lipari Giovanni, Contro Alberto, Moretti Francesca, Mansueto Giancarlo, Poli Albino
Hemodialysis Borgo Roma, Nephrology and Dialysis Unit, Department of Medicine, Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy.
Vascular Surgery Section, Department of Surgery, University of Verona, Verona, Italy.
J Vasc Access. 2020 Mar;21(2):195-203. doi: 10.1177/1129729819867552. Epub 2019 Aug 4.
Guidelines recommend hemodialysis graft screening to identify and repair significant (>50%) stenosis at high risk of thrombosis, but there is insufficient evidence to prefer one or other screening tool due to the lack of studies comparing all available options.
Seeking an optimal screening approach, we compared the performance of all currently used tools (duplex ultrasound to detect significant stenosis (StD) and measure access blood flow (QaD), ultrasound dilution access blood flow (QaU), static venous intra-access pressure ratio (VAPR), dynamic arterial and venous pressures measurement, and monitoring) for diagnosing significant angiography-proven stenosis (StA) and predicting incipient thrombosis (occurring within 4 months) in 62 grafts. All thrombotic and symptomatic acute hypotension episodes were recorded during follow-up.
VAPR > 0.70 and QaU < 1600 mL/min were the best indicators to angiography for those aiming to identify the majority of StA (91% sensitivity) and QaU < 1000 mL/min or StD for those aiming to avoid unnecessary angiograms (95%-93% positive predictive value). At Cox's analysis, the only significant thrombosis predictors were acute hypotension episodes (relative risk = 4.4 (95% confidence interval = 2.2-8.8), p < 0.0001) and QaU or QaD (14% (95% confidence interval = 8-21) or 16% (95% confidence interval = 6-25) increased risk per 100 mL/min drop in Qa, p < 0.003). Thrombosis risk (adjusted for acute hypotension) became significantly higher at QaU = 1000-700 mL/min (relative risk = 3.6 (95% confidence interval = 1.6-8.2), p < 0.001) and QaD = 1300-1000 mL/min (relative risk = 3.1 (95% confidence interval = 1.1-12.8), p = 0.031). The proportion of thromboses attributable to acute hypotension was 40% (95% confidence interval = 24-57).
Our comparative study showed that an effective screening for graft stenosis and short-term thrombosis risk can rely on Qa surveillance alone, and suggested that avoiding acute hypotension and correcting stenosis at QaU < 1000 mL/min or QaD < 1300 mL/min can contain thrombosis risk.
指南建议对血液透析移植物进行筛查，以识别并修复有血栓形成高风险的严重（>50%）狭窄，但由于缺乏比较所有可用筛查工具的研究，因此没有足够的证据表明应优先选择某一种筛查工具。
为寻求一种最佳筛查方法，我们比较了所有当前使用的工具（用于检测严重狭窄（StD）和测量通路血流量（QaD）的双功超声、超声稀释法测量通路血流量（QaU）、静态静脉内通路压力比值（VAPR）、动态动静脉压力测量及监测）在诊断经血管造影证实的严重狭窄（StA）以及预测62个移植物早期血栓形成（4个月内发生）方面的性能。在随访期间记录所有血栓形成和有症状的急性低血压发作情况。
对于旨在识别大多数StA的人而言，VAPR>0.70和QaU<1600 mL/min是血管造影的最佳指标（敏感性为91%）；对于旨在避免不必要血管造影的人而言，QaU<1000 mL/min或StD是最佳指标（阳性预测值为95%-93%）。在Cox分析中，唯一显著的血栓形成预测因素是急性低血压发作（相对风险=4.4（95%置信区间=2.2-8.8），p<0.0001）以及QaU或QaD（每100 mL/min的Qa下降，风险增加14%（95%置信区间=8-21）或16%（95%置信区间=6-25），p<0.003）。当QaU=1000-700 mL/min（相对风险=3.6（
