A national cohort study on hemodialysis arteriovenous fistulas after kidney transplantation - long-term patency, use and complications

Objective To describe the long-term hemodialysis arteriovenous fistula (AVF) patency, incidence of AVF use, incidence and nature of AVF complications and surgery in patients after kidney transplantation. Patients and methods We retrospectively analysed the AVF outcome and complications in all adult kidney allograft recipients transplanted between January 1st, 2000 and December 31, 2015 with a functional AVF at the time of transplantation. Follow-up was until December 31, 2019. Results We included 626 patients. Median AVF follow-up was 4.9 years. One month after kidney transplantation estimated AVF patency rate was 90%, at 1 year it was 82%, at 3 years it was 70% and at 5 years it was 61%; median estimated AVF patency was 7.9 years. The main cause of AVF failure was spontaneous thrombosis occurring in 76% of AVF failure cases, whereas 24% of AVFs were ligated or extirpated. In a Cox multivariate model female sex and grafts were independently associated with more frequent AVF thrombosis. AVF was used in about one third of our patients. AVF-related complications occurred in 29% of patients and included: growing aneurysms, complicated thrombosis, high-flow AVF, signs of distal hypoperfusion, venous hypertension, trauma of the AVF arm, or pain in the AVF/arm. Conclusions AVFs remain functional after kidney transplantation in the majority of patients and are often re-used after graft failure. AVF-related complications are common and require proper care.

Predictive value of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio for primary patency of percutaneous transluminal angioplasty in hemodialysis arteriovenous fistula stenosis

Objective The aim of this study is to investigate the potential association of the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) with the primary patency of percutaneous transluminal angioplasty (PTA) in hemodialysis arteriovenous fistula (AVF) stenosis. Methods This study conducted a retrospective review of patients with end-stage renal disease referred for hemodialysis AVF stenosis in one center. The study consisted of 114 patients with significant (significant stenosis was defined as a reduction in the caliber of the fistula vein of > 50% with respect to the non-aneurysmal venous segment). AVF stenosis patients were treated with PTA, with conventional balloon angioplasty. The NLR and PLR were calculated from the pre-interventional blood samples. The patients were classified into two groups: group A, primary patency < 12 months ( n = 35) and group B, and primary patency ≥ 12 months ( n = 79). Comparisons between the groups were performed using the Mann–Whitney U test. Kaplan–Meier analysis was performed to compare the factors, NLR and PLR, for association with primary patency AVFs. A receiver-operating characteristic curve analysis was performed to identify the sensitivity and specificity of the NLR and PLR cut-off values in the prediction of primary patency time. Results There was no difference in gender; age; side of AVF; AVF type; comorbid diseases such as diabetes mellitus and hypertension; or blood parameters such as white cell count, erythrocytes, hemoglobin, neutrophils, lymphocytes, monocytes, eosinophils, basophils, C-reactive protein, NLR, or PLR between the two groups ( p > 0.05). There was also no significant difference in the patency rate between the NLR < 4.13 and NLR ≥ 4.13 groups at 12 months (NLR cut-off point = 4.13, p = 0.273). There were statistically significant differences between the primary patency rates of the PLR < 187.86 and PLR ≥ 187.86 groups at 12 months (PLR cut-off point = 187.86, p = 0.023). The cut-off value for PLR for the determination of primary patency was 187.86, with a sensitivity of 57.0% and specificity of 34.4%. Conclusion An increased level of PLR may be a risk factor for the development of early AVF restenosis after successful PTA. However, more studies are needed to validate this finding.

Early Complications of Arteriovenous Fistula in patients on maintenance Hemodialysis

Background: Repeated access to circulation is essential to conduct the adequate maintenance hemodialysis. The efficiency of arteriovenous fistula, being permanent source of access to vascular system in hemodialysis, is severely hampered by its complications Aim: To determine the frequency of most common early complications of arteriovenous fistula in patients on maintenance hemodialysis. Methods: This cross sectional study was conducted over a period of five years. Total 450 patients of hemodialysis were included. Informed consent was taken and demographics were noted. Early postoperative complications of AV fistula were recorded. Results: Average age of the patients was 39.61±8.17 years. There were 255 (56.7%) males and 195 (43.3%) females. Radiocephalic fistula was constructed in 198 (44%) cases while brachiocephalic fistula in 252 (56%) cases. Among early complications, 19 (4.2%) cases had wound infection, 27 (6%) had thrombosed AV accesses and 12 (2.6%) had bleeding. Conclusion: Early complications of AVF may compromise its efficacy as source of vascular access for maintenance hemodialysis. Timey detection and management improves patient morbidity. Keywords: Maintenance Hemodialysis, Arteriovenous fistula, Infection, Thrombosis, Bleeding.

Difficult cannulation of hemodialysis arteriovenous fistula – Role of imaging in access management (DICAF STUDY)

Background: Difficulty in cannulation of arteriovenous fistula (AVF) can lead to inadequate dialysis, transient to permanent loss of access and increases dependency on bridging catheters. This study aimed to analyze the causes for difficult fistula cannulation, using various imaging modalities. Methodology: This was a retrospective single-center observational study conducted between October 2017 and June 2018. Patients whose fistulae were difficult to cannulate were initially evaluated by physical examination followed by doppler ultrasonography or/and fistulogram as necessary. The patients were divided into two groups that is, primary difficult cannulation (within first three months of creation of fistula) or secondary difficult cannulation (after three months). Results: We encountered difficult cannulation in 43 patients. About 60% were primary difficult cannulations. Most common causes for difficulty in cannulation were cannulation zone (CZ) stenosis (23.3%), immature fistula (20.9%), outflow stenosis (18.6%), inflow stenosis (11.6%), anatomical abnormalities (11.6%), outflow plus CZ stenosis (9.3%) and inflow plus CZ stenosis (4.7%). Among patients with primary difficult cannulation, immature fistula (34.6%) was the most common cause, whereas CZ stenosis (47.1%) was the most common etiology for secondary difficult cannulation. Edema leading to difficult cannulation was found in 12 patients (27.9%), all of which was due to central vein stenosis. Cannulation resulted in hematoma, fistula thrombosis, failure of fistula and pseudoaneurysm in 83.7%, 27.9%, 16.3%, and 2.3% of cases respectively. Bridging temporary dialysis catheter placement was required in 67.4% patients. Ultrasound doppler had lower diagnostic value when compared to fistulogram (71.4% vs 93.9%, p = 0.014). Conclusion: Difficulty in cannulating the arteriovenous fistula is a common problem in hemodialysis patients. We suggest that patients whose fistulae are difficult to cannulate should undergo early radiological evaluation to decrease catheter dependency and access failure.