Delamination of Acuseal early cannulation arteriovenous graft months after implantation.

Arteriovenous fistula is recommended, but arteriovenous graft is acceptable when a fistula is not possible. Acuseal is an early cannulation graft with a trilayer structure. Although primary patency rates of Acuseal appear to be similar to those of other standard grafts, few studies have investigated long-term results and complications. In our series, delamination of the wall structure occurred in 5.1% (6/115) by 21 months after Acuseal implantation. The causes could be divided into cannulation-related and cannulation-unrelated. Here, we describe the six cases in which delamination of the wall structure occurred in the medium term after Acuseal implantation.

Protein C and protein S deficiencies may be related to survival among hemodialysis patients.

BACKGROUND: Thrombophilia due to protein C (PC) and protein S (PS) deficiencies is highly prevalent among patients with stage 5 chronic kidney disease and is reported to arise due to extracorporeal circulation during hemodialysis (HD). This study aimed to evaluate the relationship between HD treatment and thrombophilia. METHODS: A total of 114 Japanese patients on maintenance HD (62 men, 52 women) were followed during 2008-2011. Their survival rates were compared against the duration of HD. Prior to each HD, coagulation/fibrinolysis parameters and PC and PS activities were measured using standard techniques. The patients were divided into two groups: Group 1, with PC and/or PS deficiencies (n = 32), and Group 2, without PC and PS deficiencies (n = 82). The influence of such deficiencies and duration of dialysis on survival was examined. Time-to-event analysis was applied using Kaplan-Meier estimates, and the log-rank test was proposed to test the equivalence of relative survival data. Hazard ratios and 95% confidence intervals (CI) were calculated. RESULTS: Of the 114 patients, 37 died (Group 1, 22; Group 2, 15). The hazard ratio (95% CI) was higher (p = 0.004) in Group 1 than Group 2. Gene analyses of PC and PS were performed in 14 patients from Group 1. No mutations in either protein were observed. We analyzed the causes of death in both groups; however, the estimated thrombophilia-related incidence of death could not be determined due to small sample size of HD patients. CONCLUSIONS: Our results suggest that PC and PS deficiencies may be related to survival in HD patients. However, this finding warrants additional research.

Duplex ultrasound for the prediction of vascular events associated with arteriovenous fistulas in hemodialysis patients.

OBJECTIVE: To determine if duplex ultrasound (US) for arteriovenous fistulas (AVFs) can predict vascular events (VEs; thrombosis and stenosis). METHODS: Duplex US was performed for vascular access evaluation in 2557 maintenance hemodialysis (HD) patients between October 1, 2013 and March 31, 2016. Of these patients, 2184 patients were finally included in this study. AVF dysfunction was assessed using the brachial artery blood flow volume (Qa; mL/min), arterial blood flow resistance index (RI), and residual diameter of the fistula vein (RD; mm). Proximal, midpoint, and distal aspects of the fistulas were measured. The baseline measurements were the US assessments, and the endpoint was VEs requiring vascular access intervention therapy or vascular surgery. Associations of US findings and VEs were assessed with receiver operating characteristic curve analysis, log-rank analysis, and multivariate Cox hazard models. RESULTS: The mean Qa was 772.8 ± 441.4 mL/min; RI, 0.56 ± 0.1; and RD, 2.37 ± 1.0 mm. The optimal Qa cut-off point was calculated as 581.5 mL/min, RI cut-off as 0.56, and RD cut-off as 1.85 mm. VEs were more frequent in patients with a Qa <581.5 mL/min than in those with a Qa >581.5 mL/min (p<0.001). In multivariate analysis, Qa, ferritin, transferrin saturation, and warfarin use were significantly associated with VEs. CONCLUSIONS: US evaluation of AVFs in HD patients is a simple method to predict the risks of thrombosis and fistula dysfunction. Qa, ferritin, transferrin saturation, and warfarin use might be associated with VEs.

Is bypass graft technique effective in arteriovenous graft?

BACKGROUND: Arteriovenous graft (AVG) requires percutaneous transluminal angioplasty (PTA) to maintain its patency; however, bypass graft technique is often chosen in cases requiring PTA again within 3 months. We retrospectively examined whether bypass graft technique is effective for AVG. METHODS: The sample patient population consisted of 50 patients who underwent bypass graft technique on the venous side of the AVG between April 2012 and March 2014. The primary and assisted patencies of the technique were calculated, and compared by the type and length of the bypass graft. Kaplan-Meier method and log-rank test were used for the calculation and comparison of the patency, respectively. p<0.05 was considered statistically significant. RESULTS: The reasons for surgery were thrombotic occlusion (27 cases), frequent PTA (15 cases) and others (8 cases). Frequent PTA was conducted within 3 months in 22 of 27 thrombotic occlusion cases (making 37/50, or 74%). Moreover, thrombectomy was required in 34 cases (68%). The 1-year primary and 1-year assisted patencies of the technique were 6.5% and 72.6%, respectively. When the endpoint was frequent PTA within 3 months after the technique, 1-year primary patency was 45.9%. CONCLUSIONS: The 1-year primary patency of the technique was poor, and patency was hard to maintain without the assistance of PTA. Given that frequent PTA was conducted in 74% of patients, it may be a cause for the poor patency. Many cases required thrombectomies, which have the disadvantage of being more invasive than PTA. We concluded that bypass graft technique is not valuable for cases that received frequent PTA.