TITLE: Hemodialysis arteriovenous fistula ligation after renal transplantation: Impact on graft resistive index

BACKGROUND: Kidney allograft resistive index (RI) is prognostic for graft and recipient survivals. Recipient hemodynamics could influence RI. In particular, dialysis arteriovenous fistula (AVF) has been involved in heart function changes, reversible after AVF ligation. Knowledge about AVF and RI is lacking. In this study, we prospectively evaluated RI changes after AVF ligation in kidney transplanted patients.

METHODS: We enrolled 22 stable transplanted patients. Mean RI was measured before AVF ligation (T0), 18 to 24 h (T1) and 6 months (T6) after surgery; mean blood pressure (mBP), heart rate (HR), serum creatinine (sCr), estimated glomerular filtration rate (eGFR), 24 h proteinuria (24 h-P), immunosuppressive drug blood levels (IS) and antihypertensive drugs were also recorded.

RESULTS: AVF ligation was performed 3.1 years (IQR: 2.1-3.8) after transplantation. Median AVF flow (Qa) was 1868 mL/min (IQR: 1538-2712) and 8 AVF were classified as high flow (Qa ≥ 2 L/min). At baseline, median sCr was 1.32 mg/dL (IQR: 1.04-1.76) and median eGFR was 57.1 mL/min. Median RI was 0.71 at T0, 0.69 at T1, 0.66 at T6. RI reduction at T1 and T6 was statistically significant (p < 0.05 and p < 0.001 respectively); in particular, 90.4% of patients had persistently improved values at T6. Furthermore, mBP increased while HR decreased. These changes were independent from sCr, 24 h-P, IS, antihypertensive drugs number, Qa and AVF type.

CONCLUSIONS: AVF ligation improves kidney allograft RI; it may reflect better kidney perfusion.

SOURCE: Magnetti M, Leonardi G, Guarena C, et al. Hemodialysis arteriovenous fistula ligation after renal transplantation: Impact on graft resistive index[J]. J Vasc Access, 2021, 22(1):129-134. DOI: 10.1177/1129729820927240. 

背景：肾脏同种异体移植抵抗指数（RI）对移植物和受体的生存具有预示性。受体的血流动力学可能会影响RI，特别是，透析动静脉内瘘（AVF）参与了心脏功能的改变，AVF结扎后可逆。而缺乏有关AVF和RI的知识。在这项研究中，我们前瞻性评估了肾移植患者AVF结扎后RI的变化。

方法：我们招募了22名稳定的移植患者。在AVF结扎前（T0），手术后18至24小时（T1）和6个月（T6）测量平均RI值；还记录了平均血压（mBP）、心率（HR）、血清肌酐（sCr）、估计的肾小球滤过率（eGFR）、24小时尿蛋白定量（24 h-P）、免疫抑制药的血药浓度（IS）和降压药。

结果：AVF结扎事件在移植后3.1年（IQR：2.1-3.8）进行。 AVF中位数流量（Qa）为1868 mL / min（IQR：1538-2712），8个AVF被评定为高流量（Qa≥ 2 L / min）。在基线时，sCr中位数为1.32 mg / dL（IQR：1.04-1.76），eGFR中位数为57.1 mL / min。 RI中位数在T0时为0.71，在T1时为0.69，在T6时为0.66。 T1和T6的RI降低具有统计学意义（分别为p <0.05和p <0.001）；特别是90.4％的患者T6值持续改善。此外，患者mBP增加，并伴随HR降低。这些变化与sCr，24 h-P，IS，降压药数量，Qa和AVF类型无关。

结论：AVF结扎可改善同种异体肾移植RI。它可能反映在更好的肾脏灌注。

启发：AVF结扎对受体的移植肾是有益的，可能改善肾灌注，但其原因仍不明了，从本研究的对象可看出，选取的患者AVF流量较高，对心脏功能影响较大，对于心脏功能影响较小的情况，是否也存在同样的结果，有待进一步研究。