Supplementary Material for: How to Reduce the Risk of Arteriovenous Fistula Dysfunction by Observing Prepump Arterial Pressure during Hemodialysis: A Multicenter Retrospective Study

Objective: Prepump arterial (Pa) pressure indicates the ease or difficulty with which the blood pump can draw blood from the vascular access (VA) during hemodialysis. Some studies have suggested that the absolute value of the Pa pressure to the extracorporeal blood pump flow (Qb) ratio set on the machine (|Pa/Qb|) can reflect the dysfunction of VA. This study was conducted to explore the impact of arteriovenous fistula (AVF) dysfunction and to explore the clinical reference value of |Pa/Qb|. Methods: We retrospectively identified adults who underwent hemodialysis at 3 hospitals. Data were acquired from electronic health records. We evaluated the pattern of the association between |Pa/Qb| and AVF dysfunction during 1 year using a Cox proportional hazards regression model with restricted cubic splines. Then, the patients were grouped based on the results, and hazard ratios were compared for different intervals of |Pa/Qb|. Results: A total of 490 patients were analyzed, with an average age of 55 (44, 66) years. There were a total of 85 cases of AVF dysfunction, of which 50 cases were stenosis and 35 cases were thrombosis. There was a U-shaped association between |Pa/Qb| and the risk of AVF dysfunction (p for nonlinearity <0.001). |Pa/Qb| values <0.30 and >0.52 increased the risk of AVF dysfunction. Compared with the group with a |Pa/Qb| value between 0.30 and 0.52, the groups with |Pa/Qb| <0.30 and |Pa/Qb| >0.52 had a 4.04-fold (p = 0.002) and 3.41-fold (p < 0.001) greater risk of AVF dysfunction, respectively. Conclusions: The appropriate range of |Pa/Qb| is between 0.30 and 0.52. When |Pa/Qb| is <0.30 or >0.52, the patient’s AVF function or Qb setting should be reevaluated to prevent subsequent failure.

研究目的：泵前动脉压（Pa pressure）可反映血液透析过程中，血泵从血管通路（VA）抽吸血液的难易程度。已有研究提示，设备设置的Pa压力与体外血泵流量（Qb）的绝对值比值（|Pa/Qb|）可反映血管通路功能异常。本研究旨在探讨动静脉内瘘（AVF）功能异常的影响，并分析|Pa/Qb|的临床参考价值。
研究方法：本研究回顾性纳入3所医院接受血液透析的成年患者，数据来源于电子健康档案。采用带限制性立方样条的Cox比例风险回归模型，分析1年内|Pa/Qb|与AVF功能异常的关联模式；随后基于分析结果对患者进行分组，比较不同|Pa/Qb|区间的风险比。
研究结果：本研究共纳入490例患者，年龄中位数为55（四分位数间距44, 66）岁。其中共发生85例AVF功能异常事件，包括50例狭窄及35例血栓形成。|Pa/Qb|与AVF功能异常风险呈U型关联（非线性检验p<0.001）。当|Pa/Qb|<0.30或>0.52时，AVF功能异常风险升高。以|Pa/Qb|处于0.30~0.52区间的患者为参照组，|Pa/Qb|<0.30及|Pa/Qb|>0.52组的AVF功能异常风险分别升高4.04倍（p=0.002）及3.41倍（p<0.001）。
研究结论：|Pa/Qb|的适宜区间为0.30~0.52。当|Pa/Qb|<0.30或>0.52时，需重新评估患者的AVF功能或Qb设置，以预防后续血管通路失效。