Background: There are controversial data about vascular access stenosis surveillance by ultrasonography. The definition of stenosis significance varies among centres. We performed a retrospective study to describe short-term outcomes of borderline asymptomatic stenoses defined by precise criteria and to determine possible risk factors of stenosis progression.
Methods: We studied the outcome of borderline stenoses in accesses with PTFE grafts. Stenosis was considered significant if there was a combination of >50% lumen reduction and peak systolic ratio >2, together with at least one of the following additional criteria: (1) residual diameter <2.0 mm and (2) flow reduction of >25% or actual flow volume <600 ml/min. Stenosis was considered borderline in the absence of the additional criteria.
Results: Of the 102 borderline stenoses, after 11 +/- 6 weeks, 55 remained non-progressive, in 38 the degree of the stenosis progressed, in 8 a percutaneous transluminal angioplasty (PTA) was performed due to clinical indication and only 1 thrombosed. A significant relative risk of developing significant stenosis was found in grafts with prior PTA [RR = 1.91 (95% CI: 1.27, 2.88), P = 0.002] and in female gender [RR = 2.29, (95% CI: 1.29, 4.06), P = 0.025].
Conclusions: Delaying PTA of borderline stenoses is safe using this watch-and-wait strategy and stenoses remain stable over at least short time, but with higher risk of progression especially after prior PTA. We believe that the definition of precise criteria of stenosis significance is necessary for the benefit of ultrasound surveillance.