Tessitore Nicola, Lipari Giovanni, Poli Albino, Bedogna Valeria, Baggio Elda, Loschiavo Carmelo, Mansueto Giancarlo, Lupo Antonio
Divisione di Nefrologia-Servizio Emodialisi Ospedale Policlinico, Università di Verona, Piazzale L.A. Scuro 10, Verona 37126, Italy.
Nephrol Dial Transplant. 2004 Sep;19(9):2325-33. doi: 10.1093/ndt/gfh316. Epub 2004 Jul 27.
Stenosis is the main cause of arteriovenous fistula (AVF) failure. It is unclear, however, if surveillance for stenosis enhances AVF function and longevity and if there is an ideal time for intervention.
In a 5-year randomized, controlled, open trial we compared blood flow surveillance and pre-emptive repair of subclinical stenoses (one or both of angioplasty and open surgery) with standard monitoring and intervention based upon clinical criteria alone to determine if the former prolonged the longevity of mature forearm AVFs. Surveillance with blood pump flow (Qb) monitoring during dialysis sessions and quarterly shunt blood flow (Qa) or recirculation measurements identified 79 AVFs with angiographically proven, significant (>50%) stenosis. The AVFs were randomized to either a control group (intervention done in response to a decline in the delivered dialysis dose or thrombosis; n = 36) or to a pre-emptive treatment group (n = 43). To evaluate a possible relationship between outcome and haemodynamic status of the access, AVFs were divided into functional and failing subgroups, according to Qa values higher or lower than 350 ml/min or the absence or presence of recirculation.
A Kaplan-Meier analysis showed that pre-emptive treatment reduced failure rate (P = 0.003) and the Cox hazards model identified treatment (P = 0.009) and higher baseline Qa (P = 0.001) as the only variables associated with favourable outcome. Primary patency rates were higher in treatment than in control AVFs in both functional (P = 0.021) and failing subgroups (P = 0.005). They were also higher in functional than in failing AVFs in both control (P<0.001) and treatment groups (P = 0.023). Access survival was significantly higher in pre-emptively treated than in control AVFs (P = 0.050), a higher post-intervention Qa being the only variable associated with improved access longevity (P = 0.044). Secondary patency rates were similar in pre-emptively treated and control AVFs in both functional (P = 0.059) and failing subgroups (P = 0.394). They were also similar in functional and failing AVFs in controls (P = 0.082), but were higher in pre-emptively treated functional AVFs than in pre-emptively treated failing AVFs (P = 0.033) or in the entire control group (P = 0.019).
We provide evidence that active blood flow surveillance and pre-emptive repair of subclinical stenosis reduce the thrombosis rate and prolong the functional life of mature forearm AVFs. We also show that Qa is a crucial indicator of access patency and a Qa >350 ml/min portends a superior outcome with pre-emptive action in AVFs.
狭窄是动静脉内瘘（AVF）失功的主要原因。然而，目前尚不清楚对狭窄进行监测是否能改善AVF功能并延长其使用寿命，以及是否存在理想的干预时机。
在一项为期5年的随机、对照、开放试验中，我们将对亚临床狭窄（血管成形术和开放手术中的一种或两种）进行血流监测和预防性修复与仅基于临床标准的标准监测和干预进行比较，以确定前者是否能延长成熟前臂AVF的使用寿命。在透析过程中通过血泵流量（Qb）监测以及每季度进行分流血流量（Qa）或再循环测量进行监测，共识别出79例经血管造影证实存在显著（>50%）狭窄的AVF。这些AVF被随机分为对照组（根据透析剂量下降或血栓形成进行干预；n = 36）或预防性治疗组（n = 43）。为评估通路的血流动力学状态与结局之间的可能关系，根据Qa值高于或低于350 ml/min或是否存在再循环，将AVF分为功能正常和功能失代偿亚组。
Kaplan-Meier分析显示，预防性治疗降低了失功率（P = 0.003），Cox风险模型确定治疗（P = 0.009）和较高的基线Qa（P = 0.001）是与良好结局相关的唯一变量。在功能正常亚组（P = 0.021）和功能失代偿亚组（P = 0.005）中，治疗组的初次通畅率均高于对照组。在对照组（P<0.001）和治疗组（P = 0.023）中，功能正常的AVF的初次通畅率也高于功能失代偿的AVF。预防性治疗组的通路生存率显著高于对照组（P = 0.050），干预后较高的Qa是与通路使用寿命改善相关的唯一变量（P = 0.044）。在功能正常亚组（P = 0.059）和功能失代偿亚组（P = 0.394）中，预防性治疗组和对照组的二次通畅率相似。在对照组中，功能正常和功能失代偿的AVF的二次通畅率也相似（P = 0.082），但在预防性治疗的功能正常AVF中，二次通畅率高于预防性治疗的功能失代偿AVF（P = 0.033）或整个对照组（P = 0.019）。
我们提供的证据表明，积极的血流监测和对亚临床狭窄的预防性修复可降低血栓形成率，并延长成熟前臂AVF的功能寿命。我们还表明，Qa是通路通畅的关键指标，Qa>350 ml/min预示着对AVF采取预防性措施会有更好的结局。
