MO770BARE METAL STENTS IN HD PATIENTS WITH CENTRAL VEIN STENOSES: TO STENT OR NOT TO STENT, THAT IS THE QUESTION
Authors: Zulkarnaev Aleksei , Stepanov Vadim , Parshina Ekaterina , Novoseltseva Mariya 
Published: May 2021

Abstract

Background and Aims
According to the current KDIGO guidelines, angioplasty should be preferred procedure for treatment of CVS instead of the bare metal stents or self-expanding stent-grafts placement. However, bare stents are still significantly more affordable than stent grafts. Aim: comparative analysis of the results of isolated balloon angioplasty (BA) and combined technique (BA with a stent placement in HD patients with central vein stenosis (CVS).

Method
A retrospective study included 62 patients with functional AVF and confirmed CVS: subclavian, brachiocephalic veins, vena cava inferior, or multiple lesions. In 39 patients, stents were not used; isolated balloon angioplasty (BA) was performed. In 23 patients we used bare metal stents during the first endovascular treatment.

Results
The use of stents leads to increase of primary patency (the time interval between the first and second endovascular interventions) – fig. 1A; HR (BA only vs. stenting) 2.064 [95% CI 1.252; 3.404], p = 0.0017. The use of stents allows to increase secondary patency (the time interval between the first endovascular intervention and the complete cessation of the use of AVF): HR=2.03 [95% CI 1.232; 3.347], p = 0.0021; fig 1B.
Total need for surgical interventions did not differ: BA only 1.511 [95% CI 1.225; 1.843] and BA+stenting 1.277 [95% CI 0.997; 1.611] per 10 patient-months, incidence rate ratio 1.183 [95% CI 0.872; 1.612] p=0.2822.
The second isolated BA allowed to increase patency compared to the first (HR of AVF function loss or relapse 0.512 [95% CI 0.32; 0.818], log rank p=0.001), and the third compared to the second isolated BA (HR=0.607 [95% CI 0.384; 0.959], log rank p=0.0157). The fourth isolated BA also showed a slight increase in AVF patency, but in this case we observed no significant difference with the previous intervention (HR= 0.783 [95% CI 0.501; 1.225], log rank p=0.2433).
In the case of BA+stenting, the second intervention, which was consisted of stent recanalization, allowed to increase patency of the AVF (HR= 0.433 [95% CI 0.231; 0.813], log rank p= 0.0014), but the third intervention was no longer accompanied by a significant increase in patency (HR= 0.873 [95% CI 0.489; 1.558], log rank p= 0.629) and AVF function was completely lost.

Conclusion
The use of stents leads to a moderate increase in the median patency of AVF and a significant increase in the proportion of patients with functional AVF in the long-term period. However, repeated surgeries are significantly less effective than in a case of isolated BA. Therefore, we consider isolated BA to be the optimal treatment strategy, and stenting should be used only if the isolated BA does not result in clinical improvement.
Multiple endovascular interventions can extend the duration of AVF functioning, however, in our study, AVF function was completely lost up to 52 months after the clinical manifestation of CVS in all patients. Thus, isolated BA and BA combined with a bare metal stent placement cannot be considered as a definitive treatment of CVS. Endovascular interventions provide only the necessary amount of time to create vascular access on the contralateral side or for shift of modality of renal replacement therapy.