Lok Charmaine E, Bhola Cynthia, Croxford Ruth, Richardson Robert M A
Department of Medicine, University Health Network, The Toronto General Hospital, Toronto, Canada.
Nephrol Dial Transplant. 2003 Jun;18(6):1174-80. doi: 10.1093/ndt/gfg122.
Thrombosis is the primary cause of access failure in polytetrafluoroethylene grafts and arteriovenous fistulas. It can lead to significant patient and access morbidity and mortality, and is difficult to prevent medically. Intervention is largely limited to maximizing access patency by detecting culprit lesions early and intervening with angioplasty or surgical revision. The most efficacious monitoring strategy is undetermined.
This 3 year prospective study took advantage of a change in monitoring strategy used in a large dialysis centre to compare the efficacy of two methods used to monitor grafts and fistulas in order to prevent access thrombosis. Accesses were monitored using Duplex ultrasonography in year 1, while the saline ultrasound dilution technique (Transonic) became the primary monitoring strategy in year 3 (year 2 was a transition year). Risk factors for thrombosis were determined using multivariate survival analysis, and the performance of Duplex ultrasonography and Transonic monitoring was assessed.
A total of 303 656 access days at risk were assessed, with 344, 385 and 425 accesses in years 1, 2 and 3, respectively. The total thrombosis rate was 1.01/1000 access days in year 1 compared with 0.66/1000 access days in year 3. This was accomplished despite a reduction in procedure rates of 55% for angiograms, 13% for angioplasties and 31% for thrombolysis.
Low flow rates detected using Transonic monitoring were associated with increased thrombosis, while stenosis detected using Duplex ultrasonography was not a strong predictor of incipient thrombosis; however, these different access characteristics were compared using monitoring techniques that may be ideal in different clinical situations.
血栓形成是聚四氟乙烯移植物和动静脉内瘘通路失败的主要原因。它可导致患者出现严重的发病情况及通路相关的发病率和死亡率，且药物预防困难。干预措施主要局限于通过早期发现病因性病变并进行血管成形术或手术修复来最大限度地维持通路通畅。最有效的监测策略尚未确定。
这项为期3年的前瞻性研究利用了一家大型透析中心监测策略的改变，比较了两种用于监测移植物和内瘘以预防通路血栓形成的方法的疗效。第1年使用双功超声监测通路，而第3年盐水超声稀释技术（Transonic）成为主要监测策略（第2年为过渡年）。使用多因素生存分析确定血栓形成的危险因素，并评估双功超声和Transonic监测的性能。
共评估了303656个有风险的通路日，第1年、第2年和第3年分别有344、385和425个通路。第1年的总血栓形成率为1.01/1000通路日，而第3年为0.66/1000通路日。尽管血管造影术的操作率降低了55%，血管成形术降低了13%，溶栓治疗降低了31%，但仍实现了这一结果。
使用Transonic监测检测到的低流速与血栓形成增加有关，而使用双功超声检测到的狭窄并不是早期血栓形成的有力预测指标；然而，这些不同的通路特征是使用可能在不同临床情况下理想的监测技术进行比较的。
