Secondary Functional Patency Research Articles

Clinical study on the establishment of radio-cephalic autogenous arteriovenous fistulas in small blood vessels by multi-segment balloon dilation technique.

To investigate the effect of dilating small blood vessels using a balloon dilation (BD) technique on the occurrence of radio-cephalic autogenous arteriovenous fistulas in terms of patency, blood flow, and vein diameter (VD). The subjects included in this study were all patients with chronic renal failure and required radio-cephalic arteriovenous fistula surgery for the first time and had not received dialysis before. Patients with VDs <2 mm were included as study subjects. They were either assigned treatment using a BD group or a control group that received hydrostatic dilation. The differences between the 2 groups were analyzed in terms of patency, blood flow, and VD. A total of 22 patients were enrolled in the balloon dilatation group and 20 patients in the control group. The diameters of cephalic veins (mm) of the experimental and control group were compared at various time points: immediately postoperation, 2.89 ± 0.42 versus 1.99 ± 0.28 (P < .001); 1 week later, 3.16 ± 0.59 versus 2.66 ± 0.60 (P = .022); 1 month later, 3.76 ± 0.91 versus 3.18 ± 0.83 (P = .087); and 2 months later, 4.08 ± 1.15 versus 3.38 ± 1.13 (P = .169). Brachial artery flows (mL/min) of the 2 groups at various time points were given as follows: immediately postoperation, 413.49 ± 145.09 versus 235.61 ± 87.77 (P < .001); 1 week later, 563.26 ± 206.83 versus 331.30 ± 126.78 (P < .001); 1 month later, 679.34 ± 218.56 versus 376.79 ± 156.25 (P < .001); and 2 months later, 736.31 ± 202.61 versus 394.60 ± 161.96 (P < .001). The primary patency at 1 year for the experimental group was 61.9% compared to 11.1% for the control group (P = .045). Similarly, the secondary patency rates at 1 year were 90.5% for the experimental group and 55.6% for the control group (P = .030). The results showed that the functional primary patency rate within 1 year was 57.1% versus 16.7% (P = .032), and the functional secondary patency rate within 1 year was 85.7% versus 50.0% (P = .038). BD has obvious advantages over hydrostatic dilation for chronic renal failure patients with small veins in establishing arteriovenous fistula in terms of patency and blood flow.

Functional patency rates of arteriovenous fistula of a retrospective cohort study from one of thebiggest centers in Canada.

The main barriers to arterio-venous fistula (AVF) utilization are primary failure, long maturation duration, and low secondary patency rates. In this retrospective cohort study, primary, secondary, functional primary, and functional secondary patency rates were calculated and compared between two age groups (< 75years and > = 75years) and between radiocephalic (RC-) and upper arm (UA-) AVFs, and factors determining the duration of functional secondary patency were evaluated. Between 2016 and 2020,206 predialysis patients whose AVFs had been created previously initiated renal replacement treatment. RC-AVFs comprised 23.3% and were created after favorable analysis of the forearm vasculature. Overall, the primary failure rate was 8.3, and 84.7% started hemodialysis with a functioning AVF. Functional secondary patency rates of primary AVFs were better with RC-AVFs [1,3 and 5year rates of 95.8, 81.9 and 81.9% versus 83.4, 71.8 and 59.2% for UA-AVFs (log rankp: 0.041)]. There was no difference between the two age groups for any of the AVF outcomes assessed. Among patients whose AVF was abandoned, 40.3% had gone on to have a second fistula created. This was significantly less likely in the older group (p < 0.01). (1) UA-AVFs were placed more commonly than RC-AVFs; (2) a selection bias existed whereby RC-AVFs were only created after favorable forearm vasculature was demonstrated or suspected; (3) superior functional secondary patency rates were observed with RC-AV's, perhaps stemming from this selection bias; (4) the elderly were more likely to have only one AVF creation attempt.

Arteriovenous fistula formation with adjuvant endovascular maturation

BackgroundThe clinical utility of the native arteriovenous fistula (AVF) has been limited by the prolonged time required for maturation, the low overall maturation rate, and subsequent abandonment. Endovascular intervention has been increasingly accepted as the first-line therapy for AVF stenosis. The objective of the present study was to evaluate the AVF formation outcomes when early endovascular intervention was selectively performed to bring about timely AVF maturation. MethodsWe performed a retrospective study (February 2014 to February 2020) of 82 AVF consecutive patients (mean age, 62.5 ± 13.5 years; range, 17-83; 58 men [70.7%]) with end-stage renal failure who had undergone vascular access construction at a single institution. The 4-year AVF patency, vascular diameters, hemodialysis parameters, reintervention rate, and mortality were analyzed. ResultsRadiocephalic AVF was the most common fistula constructed (71 patients; 88.6%). The evaluation at a mean of 46.2 ± 56.0 days (range, 5-343 days) after AVF formation revealed 33 immature AVFs (40.2%). Subsequently, 19 patients had undergone endovascular procedures, including angioplasty and/or stenting of the juxta-anastomosis, cannulation zones, and/or outflow segments to bring about timely maturation of the AVF. Hence, 93.9% of the AVFs had reached functional patency (maturation) by 6 months after formation, with a mean time to maturation of 67.8 ± 65.9 days (range, 5-320 days). After reaching maturation, the primary access functional patency was 82% ± 4.3% at 6 months, 58% ± 5.5% at 12 months, and 34% ± 6.8% at 48 months. The primary assisted access functional patency was 95% ± 2.4% at 6 months, 90% ± 3.3% at 12 months, and 83% ± 4.7% at 48 months. A total of 121 endovascular interventions were performed to maintain patency, equating to an endovascular reintervention rate of 0.37 procedure/patient year. The mean arterial, venous, and brachial flow rates did not change significantly after maturation with a mean AVF (primary assisted functional patency) survival time of 5.9 ± 0.26 years (range, 5.33-6.36 years) from maturation. Only 12 thromboses had occurred after the first follow-up review after AVF formation. These were all salvaged using endovascular techniques, leading to 100% total secondary functional patency at 4 years. The 5-year estimated all-cause mortality was 45.6% ± 12.7%. ConclusionsThe AVF maturation rate and interval to maturation were improved when early endovascular intervention was selectively performed after AVF formation. This allowed for near universal maturation. In addition, once matured, the use of ongoing endovascular reinterventions allowed for a low reintervention rate and long-term patency, providing reliable long-term renal vascular access.

Better Efficacy of Balloon Assisted Maturation in Radial-Cephalic Arteriovenous Fistula for Hemodialysis.

PurposeNative arteriovenous fistula (AVF) is the first choice for hemodialysis access; however, the maturation failure rate remains high. Hence, balloon-assisted maturation (BAM) is increasingly being used to overcome maturation failure. This study evaluated the outcomes of BAM and compared the differences between radial-cephalic (RC) and brachial-cephalic (BC) AVF.MethodsMaterials and Between January 2013 and December 2017, 1,622 new AVFs were created. BAM was considered if the AVF did not satisfy the criteria for hemodynamic maturation (6-mm diameter and 500-mL/min flow rate within 8 weeks after the operation).ResultsOf the 1,622 AVFs, BAM was performed in 142 patients (8.75%). There were 92 RC and 50 BC AVFs. Multivariate analyses revealed that ipsilateral central vein catheter history was the sole risk factor for maturation failure after BAM. One-year functional primary patency (FPP) and functional secondary patency (FSP) in RC AVFs were higher than those in BC AVFs without statistical significance (FPP, RC vs. BC: 70.9% vs. 50.9%, P=0.099; FSP, 95.5% vs. 81.1%, P=0.146). Further, based on the multivariate analysis, the independent risk factors for FPP in the RC and BC AVFs were the number of BAMs (odds ratio [OR], 3.05; 95% confidence interval [CI], 1.11-8.37; P=0.03) and age (OR, 1.04; 95% CI, 1.00-1.07; P=0.04), respectively.ConclusionBAM is a relatively good salvage method with tolerable patency. However, the risk factors for patency and the outcomes of BAM differ between RC and BC AVFs.

Risk Factors and Outcomes of Revisions on Arteriovenous Hemodialysis Access

Arteriovenous access (AV) using either a fistula (AVF) or graft (AVG) for hemodialysis (HD) access is often complicated by poor function requiring revision. We investigated the risk factors and durability of revisions on AV access sites for patients on chronic HD. This retrospective cohort study identified all patients undergoing chronic HD for over 3 months in the Champlain NephroCare network between 2003 and 2018. Access creations, revisions, and functionality were documented. Cumulative access site durability was defined as the functional duration of AV access site despite revisions. Cox regression survival analysis was performed, with competing risks for transplants and with access sites clustered by subject. We identified 1962 eligible AV access creations in 1034 subjects, composed of 1725 (88%) AVF access. Of AV, 67% underwent at least one revision, and 13% received two or more revisions. Revisions were most commonly angioplasty (95.8%). There were 354 (26%) revisions performed to assist maturation before the access site was ever functional, of which 58 were repeated revisions. Conversely, 1011 (74%) of revisions were performed to maintain functionality after the access site had been exclusively used for dialysis, of which 473 procedures were repeated revisions. Of all AV access creation attempts, 35% were never functional without secondary procedures, and another 31% experienced primary failure within the first year. However, the 12-month secondary functional patency of AV access sites was 72%. Advanced age (odds ratio [OR], 1.14; P < .01), lower arm placement (OR, 1.43; P < .01), diabetes (OR, 1.45; P < .01) and prior ipsilateral central venous catheter (OR, 1.32; P = .02) were associated with need for secondary procedures. Revisions to assist maturation were less successful on AV grafts compared with fistulas (63% vs 77%; P = .04). Revisions to maintain functionality were less successful on AV grafts, occluded access sites, or access sites with previously low dialysis flow rates. The 12-month primary patencies after revisions to maintain functionality was 82%, 73%, and 61% after the first, second, and third revisions, respectively (P < .01). Secondary procedures on AV access sites are common and generally produce accepTable Results. Multiple factors are significantly associated with the outcomes of secondary procedures. Although repeated secondary procedures produce diminishing returns, the primary patency after a third revision remains superior to that of a new AV access site.Fig 2View Large Image Figure ViewerDownload Hi-res image Download (PPT)

P1319AMBIGUOUS RESULTS OF CENTRAL VEIN STENOSIS ENDOVASCULAR TREATMENT IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Balloon angioplasty (BA) without the use of stents has unsatisfactory results, which may cast doubt on its expediency. At the same time, BA is a very expensive treatment method. We conducted a comprehensive comparative analysis of the native arteriovenous fistula (AVF) patency rates in hemodialysis patients with central venous stenosis (CVS) after endovascular BA and «open» palliative surgery. Method A retrospective study included 80 patients with confirmed central vein stenosis: subclavian, brachiocephalic veins, vena cava inferior, or multiple lesions. The main group included 39 patients who underwent percutaneous balloon angioplasty. The control group included 41 patients who did not have balloon angioplasty for various reasons. In this patients we performed only «open» palliative interventions: thrombectomy, proximalization of arteriovenous anastomosis, AVF blood flow reduction. Results Functional primary patency (the time interval between the start of AVF using and the first intervention) did not differ: groups were comparable in time of stenosis manifestation (fig. 1A). Primary patency (the time interval between the first and second interventions) after BA was statistically significantly better than in the main group (fig. 1B), but difference was minimal: median survival in the study group of 8 months [95% CI 6; 10] vs. - 6 months [95% CI 4.9; 7.1]. There was the strong negative correlation between the primary patency and functional primary patency in the main group (r = –0.627 [95%CI –0.787; –0.388], p &amp;lt;0.0001) but not in the control group (r = 0.049 [95%CI –0.262; –0.351], p = 0.7599). Thus, the later manifestation of CVS related with lower effectiveness of BA. The functional secondary patency (total duration of AVF use) in the main group was significantly better: median survival was 47 months [95% CI 40.9; 53.1] vs. 34 months [95% CI 29.8; 38.2] as well as secondary patency (the time interval between the first intervention and the complete cessation of AVF use): median survival was 16 months [95% CI 12.5; 19.5] vs. 7 months [95% CI 4.9; 9.1] (fig. 1 C and D). The occlusion-free period from the moment of starting the AVF use (functional primary assisted patency – fig. 1E) was higher in the main group, but difference was minimal: median survival was 39 months [95% CI 36.5; 41.5] vs. 32 months [95% CI 27.5; 36.5], as well as occlusion-free period from the moment of the first surgical intervention (primary assisted patency – fig. 1F) median survival was 9 months [95% CI 7; 11], in the control group - 7 months [95% CI 5.6; 8.4]. The need for open interventions was lower in the main group: 0.374 [95% CI 0.24; 0.556] and 2.451 [95% CI 1.1963; 3.023] per 10 patient-months, incidence rate ratio (IRR)= 0.153 [95% CI 0.095; 0.237], р&amp;lt;0.0001; as well as overall need for interventions: 1.511 [95% CI 1.225; 1.843] and 2.451 [95% CI 1.963; 3.023] per 10 patient-months, IRR 0.617 [95% CI 0.461; 0.825] p=0.0011. The value of AVF volume blood flow had a strong negative correlation with the primary patency in both groups (r = –0.529, p =0.0027; r = –0.419, p =0.0101). Conclusion 1. Central vein stenosis is inevitably leads to loss of vascular access on the ipsilateral side. 2. Balloon angioplasty allows to extend the period of AVF use but it is not a radical treatment method of CVS. 3. The results of balloon angioplasty are significantly affected by the length of the period from the start of AVF use to the CVS manifestation. 4. Multiple repeated BA are apparently justified in patients for whom the possibility of creating a new vascular access is doubtful. 4. The AVF volume blood flow is an important factor determining the severity of CVS clinical manifestations and the need for repeated surgical interventions.

P1329STENTING VERSUS ISOLATED BALLOON ANGIOPLASTY FOR CENTRAL VEIN STENOSIS IN HEMODIALYSIS PATIENTS

Abstract Background and Aims comparative analysis of the results of isolated balloon angioplasty (BA) and BA with stenting of central veins stenosis in patients on hemodialysis. Method A retrospective study included 62 patients with confirmed stenosis of the central veins: subclavian, brachiocephalic veins, vena cava inferior, or multiple lesions. In 39 patients, stents are not used; isolated balloon angioplasty (BA) was performed. In 23 patients we used bare metal stents. Results Functional primary patency (the time interval between the start of AVF using and the first endovascular intervention) did not differ in the groups – fig. 1A; HR 1.142 [95% CI 0.6875; 1.897], p = 0.5994. The use of stents leads to increase primary patency (the time interval between the first and second endovascular interventions) – fig. 1B; HR 2.064 [95% CI 1.252; 3.404], p = 0.0017. The use of stents allows to increase the functional secondary patency (total duration of use of the AVF) – fig 1C; HR 2.099 [95% CI 1.272; 3.463], p = 0.0016. Secondary patency (the time interval between the first endovascular intervention and the complete cessation of the use of AVF) was higher after BA with stenting: HR 2.03 [95% CI 1.232; 3.347], p = 0.0021; fig 1D. The use of stents allows to increase functional primary assisted patency (non-occlusive period from the start of AVF use) – fig. 1E and primary assisted patency (non-occlusive period from the first surgical intervention) – fig 1F: HR 1.936 [95% CI 1.175; 3.188], p= 0.0053 and HR 2.0 [95% CI 1.213; 3.295], p = 0.0042. The need for open reconstructive interventions after the first BA or BA with stenting was the same 0.374 [95% CI 0.24; 0.556] and 0.45 [95% CI 0.291; 0.664] per 10 patient-months, incidence rate ratio (IRR)= 0.831 [95% CI 0.471; 1.464] р=0.521. The need for endovascular interventions did not differ between isolated BA and BA with stenting 1.137 [95% CI 0.8913; 1.43] and 0.827 [95% CI 0.606; 1.104] per 10 patient-months, IRR=1.374 [95% CI 0.952; 1.999] p=0.09. Total need for surgical interventions (open + endovascular) also did not differ: 1.511 [95% CI 1.225; 1.843] and 1.277 [95% CI 0.997; 1.611] per 10 patient-months, IRR 1.183 [95% CI 0.872; 1.612] p=0.2822. We found a strong negative correlation between functional primary patency and primary patency (r = -0.627; p &amp;lt;0.0001) – fig. 2, as well as a between functional primary patency and secondary patency in patients after isolated BA (= -0.53; p = 0.0005, respectively), but not after stenting (r = -0.351; p = 0.101 and r = -0.304; p = 0.159, respectively). In a case of isolated BA, the success of the first intervention largely determines the secondary patency, which is expressed in a strong, statistically significant positive correlation of primary patency and secondary patency. In a case of BA with stenting, the correlation between these estimates is also statistically significant, but significantly lower. Conclusion 1. The results of balloon angioplasty without stenting are significantly influenced by the duration of the period between the start of AVF use and the manifestation of central vein stenosis. 2. The use of stents can slightly improve the results of endovascular interventions in central vein stenosis, regardless the its time of development. 3. 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 late postoperative period. 4. The use of stents does not reduce the need for surgical interventions

Ambiguous results of balloon angioplasty for central vein stenosis in hemodialysis patients with native arteriovenous fistula

Objective : to conduct comprehensive comparative analysis of the patency rate of native arteriovenous fistula (AVF) for central vein stenosis (CVS) after endovascular balloon angioplasty and palliative surgery. Materials and methods . The retrospective study included 80 patients with confirmed central vein stenosis: subclavian, brachiocephalic veins, inferior vena cava, or multiple lesions. The experimental group included 39 patients who underwent percutaneous balloon angioplasty. The control group included 41 patients who, for various reasons, did not do balloon angioplasty, but underwent palliative interventions: thrombectomy, proximalization of arteriovenous anastomosis, AVF blood flow-reducing surgical procedures. Results . Primary patency (time interval between the first intervention for CVS and the second intervention) in the experimental group was 61.5% [95% CI 44.5; 74.7] and 15.4% [95% CI 6.2; 28.3] at 6 and 12 months, respectively. In the control group, it was 39% [95% CI 24.3; 53.4] and 0% respectively. Hazard ratio (HR) 0.5337 [95% CI 0.3381; 0.8427], log-rank test p = 0.0011. No differences in functional primary patency (time interval between the start of using AVF and the first intervention for CVS) were found: 89.7% [95% CI 74.9; 96] and 30.8% [95% CI 17.3; 45.4] at 1 year and 3 years, respectively, in the experimental group, and 80.5% [95% CI 64.8; 89.7] and 24.4% [95% CI 12.7; 38.2] in the control group. There were no differences between the groups HR 0.7695 [95% CI 0.4952; 1.196], log-rank p = 0.2259. In the experimental group, strong negative correlation between primary patency and functional primary patency was detected: r = –0.627 [95% CI –0.787; –0.388], p < 0.0001. In the control group, no such correlation was found: r = 0.049 [95% CI –0.262; –0.351], p = 0.7599. Thus, the later CVS developed, the less effective balloon angioplasty was. Balloon angioplasty significantly increased duration of AVF use after first intervention for CVS (secondary patency): 84.6% [95% CI 68.9; 92.8], 66.7% [95% CI 49.6; 79.1] and 17.9% [95% CI 7.9; 31.3] at 6, 12 and 24 months, respectively in the experimental group. In the control group, it was 56.1% [95% CI 39.7; 69.6], 19.5% [95% CI 9.2; 32.7] and 0%. HR 0.4009 [95% CI 0.2481; 0.6477], log-rank p < 0.0001. Functional secondary patency (total duration of AVF use) was: 100%, 74.4% [95% CI 57.6; 85.3] and 12.8% [95% CI 4.7; 25.2] at 1, 3 and 5 years in the experimental group, and 95.1% [95% CI 81.9; 98.8], 36.6% [95% CI 22.3; 51] and 4.9% [95% CI 0.9; 14.5] in the control group. HR 0.5661 [95% CI 0.3598; 0.8906], log-rank p = 0.0067. Conclusions . 1. Central vein stenosis inevitably cuts vascular access from the ipsilateral side. 2. Balloon angioplasty allows to slightly prolong AVF use but it cannot radically change the long-term results of CVS treatment. 3. The outcome of balloon angioplasty greatly depends on the length of the period from the time the use of AVF started to the time CVS developed. 4. Multiple repeated balloon angioplasties are apparently justified in patients for whom creating a new vascular access might not be possible. 4. AVF volumetric blood flow velocity is an important factor determining the severity of CVS clinical manifestations and whether repeated surgical interventions are needed.

Factors Associated with Secondary Functional Patency After Percutaneous Transluminal Angioplasty of the Early Failing or Immature Hemodialysis Arteriovenous Fistula.

To evaluate the efficacy of percutaneous transluminal angioplasty for early failing hemodialysis arteriovenous fistulas (AVFs) and predictors of secondary functional patency (FP). A review of our endovascular registry database showed that 61 patients with early failure after a surgically created AVF underwent endovascular intervention between 2011 and 2016. Median time from AVF creation to first intervention was 5.6weeks. Median duration of follow-up was 14months. Items related to the technical success rate and primary and secondary FP, and factors associated with secondary FP were analyzed. Technical success was achieved in 55 (90%) of 61 patients. The primary and secondary FP rates were 42% and 65% at 12months, respectively. Multivariate analysis showed that lesion length (HR; 1.15, P = 0.001) and lesions including juxta-AVF (the portion of fistula vein within 2cm of the arteriovenous anastomosis, HR; 6.23, P = 0.008) were factors associated with reduced secondary FP. ROC curve analysis indicated lesion length with cutoff value ≥ 9cm as a risk factor for reduced secondary FP. Secondary FP at 12months for patients with no risk factors, with 1, and with 2 was 86%, 65%, and 0%, respectively. There was a significant difference in secondary FP rates among these groups (P = 0.001). A lesion length and juxta-AVF lesion are the risk factors for reduced secondary FP. The secondary FP rate at 12months is acceptable in patients without risk factors.

A Systematic Review and Meta-Analysis of Randomized Trials Comparing Two-Stage with One-Stage Brachio-Basilic Vein Fistulas.

PurposeThere is currently debate if brachio-basilic vein fistula (BBVF) should be performed as a one-stage or two-stage procedure. The aim of the present study was to perform a systematic review and meta-analysis on BBVF staging.Materials and MethodsOn February 25, 2016, a search for randomized-controlled trials (RCTs) on BBVF procedures was performed in MEDLINE and Scopus databases. Meta-analyses were performed with fixed-effect or random-effects models as appropriate with risk ratios (RRs). The primary efficacy and safety outcome measures were BBVF maturation and development of complications, respectively. Specific types of complications, including loss of functional secondary patency and long-term complications were all secondary outcome measures.ResultsWe identified three RCTs reporting on 126 patients. Maturation failure of two-stage BBVFs (3/47, 6.4%) was less frequent than one-stage BBVFs (16/79, 20.3%; RR, 0.27; P=0.02). Complication rates of two-stage and one-stage BBVFs were similar (RR, 0.80; P=0.54), but on sensitivity analysis these were less likely to occur with two-stage BBVFs (37% vs. 69% for one-stage BBVFs; RR, 0.57; P=0.03). Two-stage BBVFs were less likely to lose their functional secondary patency (21.3% vs. 31.6% for one-stage BBVFs; RR, 0.61; P=0.11). This non-significant trend became significant (RR, 0.36; P=0.02) on sensitivity analysis. There was no difference in specific complication rates of the two study groups.ConclusionAmong candidates for BBVF fistula, there is evidence to suggest that two-stage BBVFs achieve higher maturation rates compared to one-stage BBVFs. The evidence for difference in long-term secondary patency is less robust, calling for further research.

3:10 PM Abstract No. 232 Factors associated with the secondary functional access patency after percutaneous transluminal angioplasty of the early failing or immature hemodialysis arteriovenous fistula

To evaluate the efficacy of percutaneous transluminal angioplasty (PTA) for early failing hemodialysis arteriovenous fistula (AVF) and predictive factors for the secondary functional patency. A review of the endovascular registry database for our department showed 61 patients with the early failure after the surgically created AVF underwent endovascular intervention between July 2011 and October 2016. The patients were characterized by being 48% male with median age of 68 years. The median of the duration of time from AVF creation to first intervention was 5.6 weeks (range, 1-12 weeks). Median duration of follow-up was 14 months. Items concerning technical success rate, primary and secondary functional patency, factors associated with secondary functional patency were analyzed. Angiography revealed 38 stenoses and 23 occlusions. Median length of lesions was 4.5 cm (range; 1-25 cm). Technical success was achieved in 55 (90%) of 61 patients. The primary and secondary functional patency rates were 42% and 65% at 12 months, respectively. Univariate analysis indicated that lesion length (p = 0.009) and lesions including juxta-AVF (p = 0.057) should be considered as a risk factor for secondary functional patency. Multivariate analysis using Cox proportional hazards regression model indicated lesion length (hazard ratio; 1.15, P = 0.001) and lesion including juxta-AVF (hazard ratio; 6.30, P = 0.008) as a risk factor associated with secondary functional patency. ROC curve analysis indicated lesion length ≥9 cm as a cutoff value of a risk factor for secondary functional patency. The secondary functional patency at 12 months was 86% for patients with no risk factor (n = 23), 65% for patients with 1 risk factor (n = 33), and 0% for patients with 2 risk factors (n = 5). There was significant difference in secondary functional patency rate among these groups (P = 0.001). The juxta-AVF lesion and length of lesions are the risk factors for the secondary functional patency. Secondary functional patency rate at 12 months is acceptable in patients without risk factors.

Comparative effectiveness of one-stage versus two-stage basilic vein transposition arteriovenous fistulas

ObjectiveBasilic vein transposition (BVT) fistulas may be performed as either a one-stage or two-stage operation, although there is debate as to which technique is superior. This study was designed to evaluate the comparative clinical efficacy and cost-effectiveness of one-stage vs two-stage BVT. MethodsWe identified all patients at a single large academic hospital who had undergone creation of either a one-stage or two-stage BVT between January 2007 and January 2015. Data evaluated included patient demographics, comorbidities, medication use, reasons for abandonment, and interventions performed to maintain patency. Costs were derived from the literature, and effectiveness was expressed in quality-adjusted life-years (QALYs). We analyzed primary and secondary functional patency outcomes as well as survival during follow-up between one-stage and two-stage BVT procedures using multivariate Cox proportional hazards models and Kaplan-Meier analysis with log-rank tests. The incremental cost-effectiveness ratio was used to determine cost savings. ResultsWe identified 131 patients in whom 57 (44%) one-stage BVT and 74 (56%) two-stage BVT fistulas were created among 8 different vascular surgeons during the study period that each performed both procedures. There was no significant difference in the mean age, male gender, white race, diabetes, coronary disease, or medication profile among patients undergoing one- vs two-stage BVT. After fistula transposition, the median follow-up time was 8.3 months (interquartile range, 3-21 months). Primary patency rates of one-stage BVT were 56% at 12-month follow-up, whereas primary patency rates of two-stage BVT were 72% at 12-month follow-up. Patients undergoing two-stage BVT also had significantly higher rates of secondary functional patency at 12 months (57% for one-stage BVT vs 80% for two-stage BVT) and 24 months (44% for one-stage BVT vs 73% for two-stage BVT) of follow-up (P < .001 using log-rank test). However, there was no significant difference between groups in use of interventions (58% for one-stage BVT vs 51% for two-stage BVT; P = .5) to maintain patency. These findings were confirmed in multivariate analysis, in which two-stage BVTs were associated with a significantly lower rate of failure (hazard ratio, 0.39; 95% confidence interval, 0.2-0.8; P < .05) than one-stage BVTs after controlling for confounding variables. Finally, the two-stage BVT was more cost-effective (3.74 QALYs for two-stage BVT vs 3.32 QALYs for one-stage BVT) during 5 years, with an incremental cost-effectiveness ratio of $4681 per QALY. ConclusionsOur data show that two-stage BVTs are more durable and cost-effective than one-stage procedures, with significantly higher patency and lower rates of failure among comparable risk-stratified patients. These findings suggest that additional upfront costs and resources associated with creating two-stage BVTs are justified by their long-term outcomes.

The Significance of Inflow Artery and Tourniquet Derived Cephalic Vein Diameters on Predicting Successful Use and Patency of Arteriovenous Fistulas for Haemodialysis

To investigate the significance of inflow artery and cephalic vein diameters on predicting patency of radiocephalic and brachiocephalic arteriovenous fistulas (AVFs). Single centre study with retrospective analysis of prospectively collected data between November 2010 and July 2015. A detailed history and physical examination was undertaken, including age, gender, history and duration of haemodialysis, cause of chronic kidney disease, and the presence of comorbidities/risk factors. Pre-operative arterial and venous upper extremity mapping was performed and inner vessel diameter was recorded, using a tourniquet for the veins. Outcome measures included AVF use (functionality), primary, primary assisted, secondary, and functional secondary patency. One hundred and thirty five AVFs (57 and 78 radiocephalic and brachiocephalic AVFs, respectively) were constructed and followed up for 5 years. A cephalic vein diameter <4.3mm (lower three quartiles) was the single independent predictor of inferior secondary and also functional secondary patency of radiocephalic AVFs (p=.02, HR 11.2, 95% CI 1.44-90.9). A brachial artery diameter ≤4.1mm (lowest quartile) was an independent predictor of AVF functionality (57% vs. 83% for larger arteries, p=.017), and inferior primary, primary assisted, secondary, and functional secondary patency of brachiocephalic AVFs (primary assisted patency 21.9% vs. 55.9% at 3 years, p=.001/log-rank test, HR 3.1, p=.002/Cox regression). The presence of lower extremity PAD or use of dual antithrombotics was also independently associated with an inferior secondary patency. The number of risk factors (brachial artery diameter ≤4.1mm, PAD, and use of dual antithrombotics) demonstrated risk stratification capabilities for functional secondary patency. Among patients undergoing radiocephalic AVFs, a tourniquet derived cephalic vein diameter <4.3mm was the single independent predictor of inferior secondary and functional secondary patency. Among patients undergoing brachiocephalic AVFs, all patency rates were inferior in the presence of a brachial artery diameter ≤4.1mm and secondary patency was inferior in the presence of multiple risk factors.

Initial clinical experience with a polytetrafluoroethylene vascular dialysis graft reinforced with nitinol at the venous end

ObjectiveThe purpose of this study was to examine the outcomes of a vascular hybrid polytetrafluoroethylene (PTFE) graft, provided with a nitinol-reinforced section (NRS) on one end, in hemodialysis vascular access placement. MethodsA retrospective study was conducted including all the consecutive patients who underwent Gore Hybrid Vascular Graft (GHVG; W. L. Gore & Associates, Flagstaff, Ariz) implantation for hemodialysis access placement between October 2013 and November 2015. A propensity-matched control group was obtained from consecutive patients who underwent standard PTFE arteriovenous graft implantation between January 2010 and July 2013. The selection criteria were inadequate venous material for autogenous arteriovenous fistula placement, patent deep venous circulation, and vein diameter of 4 to 8.5 mm. The implantation technique involves the insertion of the NRS some centimeters into the target vein. Fluoroscopic guidance helps deploy the device in the desired landing zone (ie, position of the proximal end of the NRS), based on anatomic landmarks. Survival, functional patency rates, and complications were compared with a propensity-matched historical control group. Vein diameter, previous vascular access placement, and diabetes were tested as predictors of reintervention with a logistic regression analysis. ResultsThere were 32 patients (14 men; mean age, 69 ± 14 years) who received the GHVG graft. The historical control group included 43 patients. Technical success was 100%. The graft configuration was brachial-axillary (n = 22 [69%]), brachial-basilic loop (n = 5 [16%]), brachial-antecubital loop (n = 3 [9%]), axilloaxillary loop (n = 1 [3%]), and femoral-femoral loop (n = 1 [3%]). Mean NRS oversize was 20% ± 7% (range, 3%-34%; median, 19%). Perioperative complications requiring revision included acute limb ischemia treated with thrombectomy (n = 1 [3%]) and graft infection requiring explantation (n = 2 [6%]). Two patients (6%) died in the hospital of unrelated causes. The mean follow-up was 15 ± 11 months (range, 0-33 months; median, 15.5). The propensity-matched groups included 25 patients each. Survival estimates at 24 months for the GHVG and standard PTFE groups were 91% ± 6% and 82% ± 9% (P > .05), respectively. The 12-month patency estimates were as follows: functional primary patency, 66% ± 10% vs 51% ± 10% (P > .05); functional assisted primary patency, 75% ± 9% vs 51% ± 10% (P > .05); and functional secondary patency, 79% ± 9% vs 67% ± 10% (P > .05). Reduction in vein diameter was associated with reintervention. ConclusionsThe GHVG is a safe and effective alternative to standard PTFE in hemodialysis access surgery. Careful planning for the landing zone is advisable, especially for small outflow veins. Larger studies and randomized trials are needed to define the role for this device. A study including a greater number of centers experienced with this device is currently under way.

Treatment of Hemodialysis Vascular Access Rupture Irresponsive to Prolonged Balloon Tamponade: Retrospective Evaluation of the Effectiveness of N-Butyl Cyanoacrylate Seal-Off Technique

ObjectiveThe current study retrospectively evaluated whether the percutaneous N-butyl cyanoacrylate (NBCA) seal-off technique is an effective treatment for controlling the angioplasty-related ruptures, which are irresponsive to prolonged balloon tamponade, during interventions for failed or failing hemodialysis vascular accesses.Materials and MethodsWe reviewed 1588 interventions performed during a 2-year period for dysfunction and/or failed hemodialysis vascular access sites in 1569 patients. For the angioplasty-related ruptures, which could not be controlled with repeated prolonged balloon tamponade, the rupture sites were sealed off with an injection of a glue mixture (NBCA and lipiodol), via a needle/needle sheath to the rupture site, under a sonographic guidance. Technical success rate, complications and clinical success rate were reported. The post-seal-off primary and secondary functional patency rates were calculated by a survival analysis with the Kaplan-Meier method.ResultsTwenty ruptures irresponsive to prolonged balloon tamponade occurred in 1588 interventions (1.3%). Two technical failures were noted; one was salvaged with a bailout stent-graft insertion and the other was lost after access embolization. Eighteen accesses (90.0%) were salvaged with the seal-off technique; of them, 16 ruptures were completely sealed off, and two lesions were controlled as acute pseudoaneurysms. Acute pseudoaneurysms were corrected with stentgraft insertion in one patient, and access ligation in the other. The most significant complication during the follow-up was delayed pseudoaneurysm, which occurred in 43.8% (7 of 16) of the completely sealed off accesses. Delayed pseudoaneurysms were treated with surgical revision (n = 2), access ligation (n = 2) and observation (n = 3). During the follow-up, despite the presence of pseudoaneurysms (acute = 1, delayed = 7), a high clinical success rate of 94.4% (17 of 18) was achieved, and they were utilized for hemodialysis at the mean of 411.0 days. The post-seal-off primary patency vs. secondary patency at 90, 180 and 360 days were 66.7 ± 11.1% vs. 94.4 ± 5.4%; 33.3 ± 11.1% vs. 83.3 ± 8.8%; and 13.3 ± 8.5% vs. 63.3 ± 12.1%, respectively.ConclusionOur results suggest that the NBCA seal-off technique is effective for immediate control of a venous rupture irresponsive to prolonged balloon tamponade, during interventions for hemodialysis accesses. Both high technical and clinical success rates can be achieved. However, the treatment is not durable, and about 40% of the completely sealed off accesses are associated with developed delayed pseudoaneurysms in a 2-month of follow-up. Further repair of the vascular tear site, with surgery or stent-graft insertion, is often necessary.

Description and outcomes of a simple surgical technique to treat thrombosed autogenous accesses

Owing to the difficulty of removing acute and chronic thrombus from autogenous accesses (AA) by standard surgical and endovascular techniques, many surgeons consider efforts to salvage a thrombosed AA as being futile. We describe a simple technique to extract acute and chronic thrombus from a failed AA. This technique involves making an incision adjacent to the anastomosis, directly extracting the arterial plug, and manually milking thrombus from the access. This report details the outcomes of a series of thrombosed AAs treated by surgical thrombectomy/intervention using this technique for manual clot extraction. A total of 146 surgical thrombectomies/interventions were performed in 102 patients to salvage a thrombosed AA. Mean follow-up was 15.6 months. Office, hospital, and dialysis unit records were reviewed to identify patient demographics, define procedure type, and determine functional patency rates. Kaplan-Meier survival analysis was used to estimate primary and secondary functional patency rates. Complete extraction of thrombus from the AA was achieved in 140 of 146 cases (95%). The studied procedure itself was technically successful in 127 cases (87%). Reasons for failure were the inability to completely extract thrombus from the AA in six, failed angioplasty due to long segment vein stenosis or sclerosis in seven or vein rupture in two, and central vein occlusion in one. Three failures occurred for unknown causes ≤ 3 days of successful thrombectomy. No single factor analyzed (age, sex, race, diabetes status, access type or location) was associated with technical failure. The estimated primary and secondary functional patency rates were 27% ± 5% and 61% ± 6% at 12 months. The manual clot extraction technique described in this report effectively removed acute and chronic thrombus from failed AAs. Its use, combined with an intervention to treat the underlying cause for AA failure, significantly extended access durability.

Ethnic differences in arm vein diameter and arteriovenous fistula creation rates in men undergoing hemodialysis access

The National Kidney Foundation recommends that arteriovenous fistulas (AVFs) be placed in at least 65% of hemodialysis patients. Some studies suggest that African American patients are less likely to receive a first-time AVF than patients of other ethnicities, although the reason for this disparity is unclear. The purpose of our study is to determine (1) whether there are ethnic differences in AVF creation, (2) whether this may be related to differences in vein diameters, and (3) whether AVF patency rates are similar between African American and non-African American male patients. Consecutive male patients undergoing first-time hemodialysis access from 2006 to 2010 at two institutions were retrospectively reviewed. Data collected included age, ethnicity, weight, height, body mass index, diabetes, hypertension, congestive heart failure, smoking history, intravenous drug abuse, need for temporary access placement, and preoperative venous ultrasound measurements. Categoric variables were compared using χ(2) analysis, and the Wilcoxon rank-sum test was used to compare continuous variables. Of 249 male patients identified, 95 were African American. Median age in African American and non-African American patients was 63 years. Hypertension and hyperlipidemia were statistically significantly greater in African American patients. The need for temporary access before hemoaccess was similar between the cohorts. African American patients demonstrated significantly smaller median basilic and cephalic vein diameters at most measured sites. Overall, 221 of 249 (88.8%) underwent AVF first. An AV graft was created in 17.9% of African American patients vs in only 7.1% of non-African Americans (odds ratio, 2.8; 95% confidence interval, 1.3-6.4; P = .009). The difference between median vein diameters used for autologous fistula creation in African American and non-African American patients was not significant. There was no significant difference in the primary patency (80.8% vs 76.2%; P = .4), primary functional patency (73.1% vs 69.2%; P = .5), or secondary functional patency rates (91.0% vs 96.5%; P = .1). Average primary fistula survival time was 257 days in African American and 256 in non-African American patients (P = .2). African American patients are less likely than non-African American patients to undergo AVF during first-time hemodialysis access surgery. This ethnic discrepancy appears to be due to smaller arm vein diameters in African American patients. In African American patients with appropriate vein diameters who do undergo AVF, primary and functional patencies are equivalent to non-African American patients.

A comparison between one- and two-stage brachiobasilic arteriovenous fistulas

Brachiobasilic arteriovenous fistulas (BBAVF) can be performed in one or two stages. We compared primary failure rates, as well as primary and secondary patency rates of one- and two-stage BBAVF at two institutions. Patients undergoing one- and two-stage BBAVF at two institutions were compared retrospectively with respect to age, sex, body mass index, use of preoperative venous duplex ultrasound, diabetes, hypertension, and cause of end-stage renal disease. Categorical variables were compared using chi-square and Fisher's exact test, whereas the Wilcoxon rank-sum test was used to compare continuous variables. Patency rates were assessed using the Kaplan-Meier survival analysis and the Cox proportional hazards model with propensity analysis to determine hazard ratios. Ninety patients (60 one-stage and 30 two-stage) were identified. Mean follow-up was 14.2 months and the mean time interval between the first and second stage was 11.2 weeks. Although no significant difference in early failure existed (one-stage, 22.9% vs two-stage, 9.1%; P = .20), the two-stage BBAVF showed significantly improved primary functional patency at 1 year at 88% vs 61% (P = .047) (hazard ratio, 0.2 (95% confidence interval [CI], .04-.80; P = .03). Patency for one-stage BBAVF markedly decreased to 34% at 2 years compared with 88% for the two-stage procedure (P = .047). Median primary functional patency for one-stage BBAVF was 31 weeks (interquartile range [IQR], 11-54) vs 79 weeks (IQR, 29-131 weeks) for the two-stage procedure, respectively (P = .0015). Two-year secondary functional patency for one- and two-stage procedures were 41% and 94%, respectively (P = .015). Primary and secondary patency at 1 and 2 years as well as functional patency is improved with the two-stage BBAVF when compared with the one-stage procedure. Lower primary failure rates prior to dialysis with the two-stage procedure approached, but did not reach statistical significance. While reasons for these finding are unclear, certain technical aspects of the procedure may play a role.

A Novel Fluoroscopic-Assisted Balloon Thrombectomy: Technique for Thrombosed Hemodialysis Prosthetic Grafts

Previous studies have shown that stenosis of the arterial anastomosis of thrombosed hemodialysis (HD) grafts, unmasked after conventional thrombectomy, very often necessitate subsequent arterial angioplasty. The aim of this study was to describe a novel fluoroscopic-assisted balloon thrombectomy technique which permits simultaneous arterial angioplasty (should this is required) for thrombosed HD grafts. Thirty patients with 36 thrombotic episodes of their prosthetic HD grafts participated in this study. A balloon angioplasty catheter is placed beyond the arterial anastomosis, over a guidewire; the balloon is inflated with contrast solution under fluoroscopy and pulled back to remove the arterial thrombus from the anastomosis. Any coexisting stenosis revealed by balloon indentation is completely dilated at that time, rather than after the thrombectomy. Mechanical thrombolysis of the graft and venous outflow is then performed with the AngioJet catheter (Possis Medical, Inc). Technical and clinical success rates (the latter defined as one subsequent HD session) of the procedure were 100% and 94%, respectively. No complications, including arterial embolism, vessel rupture or pulmonary embolism, were encountered. Primary assisted patency at 3 and 6 months was 51% and 32%, respectively, while functional secondary patency at the same follow-up points was 78%. Our technique is safe and also effective in both short- and long-term follow-up. Because it offers convenience, since the treatment of arterial anastomotic stenoses is accomplished in one (rather than two) steps, this method deserves further investigation.

Fistula Elevation Procedure: Experience with 295 Consecutive Cases During a 7-Year Period

Up to 50% of AV fistulas fail to mature, primarily because of problems with fistula cannulation. Fistula elevation procedure (FEP) is a simple superficialization procedure where the fistula is surgically exposed, mobilized, and elevated into a more superficial position for the purpose of facilitating AV fistula cannulation. The purpose of this study is to review use of FEP as an adjunct to fistula maturation. Two hundred ninety-five FEPs were performed between February 1999 and December 2005. FEP was performed if the fistula was considered too deep to cannulate or if nurses were unable to cannulate the fistula. Kaplan-Meier life-table analysis was used to determine patency and for a subanalysis by location of FEP performed (172 brachial-cephalic, 70 brachial-basilic, 46 radial-cephalic, 7 superficial femoral vein). Survival curves were compared using log-rank test. Functional primary patency rates for patients undergoing an adjunctive FEP were 73% at 6 months, 60% at 1 year, and 46% at 2 years. Secondary functional patency rates were 81% at 6 months, 71% at 1 year, and 59% at 2 years. There was no statistical significance in any outcomes based on anatomic site of elevation. AV fistulas that might otherwise have been abandoned because of excessive depth or tortuosity can be successfully salvaged by an adjunctive FEP and achieve satisfactory longterm functional patency. FEP is a valuable adjunct to AV fistula creation, which will enhance fistula maturation rates.