P1326NATIVE AVF ANEURYSMS RECONSTRUCTION: THE MULTI-CENTER EXPERIENCE
Authors: Zulkarnaev Aleksei , Baykov Boris , Strugaylo Ewgenii , Kardanakhishvili Zurab , Fominykh Natalia , Stepanov Vadim 
Published: June 2020

Abstract

Background and Aims
to analyze the results of surgical correction of native arteriovenous fistula (AVF) aneurysms in hemodialysis patients.

Method
A retrospective observational study included 158 patients who underwent various surgical interventions. 87 patients (55.1%) underwent pre-emptive surgeries. 71 patients (44.9%) underwent surgeries after AVF thrombosis («on demand» surgery).
In the presence of high-flow AVF or in a case of high risk of fistula vein rupture, aneurysmorrhaphy was performed, which was supplemented by transposition of the reconstructed vein – fig. 1. In a case of paraanastomotic stenosis of the vein, aneurysmorrhaphy was enhanced by arteriovenous anastomosis proximalization. In a case of local proximal or distal stenosis of the functional segment of the vein, aneurysmorrhaphy was supplemented with stenosis plastic using the wall of the resected aneurysm. In a case of prolonged proximal stenosis or totally thrombosed proximal aneurysm, the fistula blood flow was switched to v. basilica with its transposition. In the case of a totally thrombosed distal aneurysm, it was excised and proximal AVF was created.

Results
In the case of pre-emptive surgeries, secondary patency was 69% [95% CI 44.9; 84.2] after 4.8 years (maximum follow-up). In the case of on-demand surgeries the secondary patency was 45.6% [95% CI 23.6; 65.2] after 4.3 years (maximum follow-up) – fig. 2. HR (log rank test) pre-emptive vs. on demand surgeries 0.296 [95% CI 0.147; 0.592], inverse HR = 3.381 [95% CI 1.674; 6.827], p = 0.0002.
The risk AVF function loss was lower in patients who received pre-emptive surgeries compared with patients who received on-demand surgery: 2.642 [95% CI 1.406; 4.519] versus 6.268 [95% CI 3.927; 9.49] per 100 patient-years, incidence rate ratio (IRR) = 0.422 [95% CI 0.207; 0.834] (inverse estimate IRR=2.372 [95% CI 1.2; 4.842]), p = 0.0127.
The need for CVC was also lower in patients who received pre-emptive surgeries: 1.728 [95% CI 1.38; 2.136] versus 2.821 [95% CI 2.292; 3.434] per 10 patient-years, IRR=0.6125 [95% CI 0.4576; 0.8185] (inverse estimate IRR= 1.633 [95% CI 1.222; 2.185]), p = 0.0009.
Moreover, the number of operations was significantly higher in patients who underwent pre-emptive surgeries: 4.207 [95% CI 3.654; 4.821] versus 2.963 [95% CI 2.421; 3.59] per 10 patient-years, IRR=1.42 [95% CI 1.124; 1.802] (inverse estimate IRR= 0.704 [95% CI 0.555; 0.89]), p=0.0031.
In almost all cases, fistula vein aneurism has been associated with various hemodynamic disorders. The median volume blood flow Qa was 2.9 [interquartile range - IQR 1.9; 3.8] l/min., (minimum. 1 l/min., max. 4.5 l/min.). Reconstruction in most cases led to significant change in Qa (p&lt;0.0001). After reconstruction, the Qa median was 1.8 [IQR 1.6; 2.1] l/min. (minimum 1.4 l/min., max. 2.1 l/min). It is noteworthy that in patients with low Qa values, Qa increased slightly, and at high values, it decreased significantly. However, additional methods of blood flow reducing were not used. The median of the Qa difference was -1.2 [IQR -1.9; -0.2] l/min. (minimum -2.7 l/min, max. 1 l/min.).

Conclusion
The indication for surgical treatment is not just aneurism, but its complications, the high risk of complications development or a combined pathology. Preventive surgical interventions can significantly extend the AVF patency and reduce the need for central venous catheters, however, this is achieved by significantly increasing the number of surgeries. The concept of routine monitoring of a normally functioning AVF by a surgeon should replace the concept of on-demand surgery in case of AVF thrombosis or development of other serious complications.