Pathological evaluation of a fluoropolymer-based drug-eluting stent in an arteriovenous graft outflow venous stenosis.

A fluoropolymer-based drug-eluting stent was implanted in an arteriovenous graft outflow venous stenosis. Two and a half years later, due to a local infection, the stent was removed surgically, and a pathological evaluation was conducted. The stent struts exhibited partial endothelial cell coverage, with the remaining surface predominantly covered by fibrin. Notably, there was no evidence of restenosis or aneurysmal change.

Ultrasound-Assessed Lesion Morphology and Drug-Coated Balloon Treatment for de novo Dysfunctional Arteriovenous Fistula in Hemodialysis Patients.

AIM: This study aimed to evaluate the effect of ultrasound-assessed lesion morphology on the outcomes of drug-coated balloon (DCB) versus plain old balloon angioplasty (POBA) treatment for de novo dysfunctional arteriovenous fistulas (AVF) lesions. METHODS: This single-center retrospective study enrolled 114 consecutive patients (mean age, 73 ± 10 years; male, 69%) with de novo dysfunctional AVF lesions who underwent percutaneous transluminal angioplasty (PTA) using DCB (n = 48) and POBA (n = 66). The morphology of the stenotic lesions, evaluated using ultrasonography, was classified into intimal hyperplasia and shrinking types. The outcome measure was 12-month primary patency. Factors associated with loss of primary patency were evaluated using Cox proportional hazards models. RESULTS: The baseline characteristics were not significantly different between the 2 treatment groups. The 12-month primary patency rate was significantly higher in the DCB group than in the POBA group (66.8 ± 7.1% versus 35.9 ± 6.3%, P = .006). The 12-month primary patency rate in the lesions with intimal hyperplasia type was not significantly different (DCB: 70.3 ± 9.5% versus POBA: 45.9 ± 8.0%; P = .310), whereas that in the shrinking type was significantly higher in the DCB group than in the POBA group (61.9 ± 10.6% versus 15.2 ± 8.1%; P < .001). The interaction analysis demonstrated that lesion morphology had a significantly different hazard ratio (HR) for restenosis between the POBA and DCB groups (P for interaction = .031). The multivariate analysis revealed that DCB usage (adjusted hazard ratio [aHR], 0.49; 95% confidence interval [CI]: [0.28, 0.87]; P = .015), ultrasound-assessed lesion morphology (shrinking type: aHR, 1.77; 95% CI: [1.07, 2.93]; P = .026), and location of stenosis (aHR, 2.26; 95% CI: 1.15, 4.46; P = .018) were significantly associated with AVF patency after PTA. CONCLUSION: This study revealed that lesion morphology evaluated using ultrasonography had a differential impact on DCB and POBA outcomes. The therapeutic effect of DCB was unexpectedly confirmed in the shrinking type. CLINICAL IMPACT: The effectiveness of DCB in inhibiting smooth muscle cell proliferation in intimal hyperplasia lesions was expected based on the known mechanism of action of paclitaxel. However the therapeutic effect of DCB was unexpectedly confirmed in the shrinking type too. We may not need to hesitate usage of DCB for shrinking type.

IN.PACT AV Access Randomized Trial of Drug-Coated Balloons for Dysfunctional Arteriovenous Fistulae: Clinical Outcomes through 36 Months.

PURPOSE: To present the 36-month outcomes of the prospective randomized IN.PACT AV Access study of participants with obstructive de novo or restenotic native upper extremity arteriovenous dialysis fistula lesions treated with drug-coated balloon (DCBs) or standard percutaneous transluminal angioplasty (PTA) following successful high-pressure PTA. MATERIALS AND METHODS: Participants at 29 international sites were randomized 1:1 to receive an IN.PACT AV DCB (n = 170) or undergo PTA (n = 160). The outcomes through 36 months included target lesion primary patency (TLPP) and access circuit primary patency (ACPP) (composites of clinically driven target lesion or access circuit revascularization and/or access circuit thrombosis), number of reinterventions, and serious adverse events involving the access circuit. RESULTS: TLPP was 52.1% in the DCB group compared with 36.7% in the PTA group through 24 months and 43.1% in the DCB group compared with 28.6% in the PTA group through 36 months (both log-rank P < .001). ACPP was 39.4% in the DCB group compared with 25.3% in the PTA group through 24 months and 26.4% in the DCB group compared with 16.6% in the PTA group through 36 months (both log-rank P < .001). Cumulative incidence of access circuit thrombosis through 36 months was 8.2% in the DCB group compared with 18.3% in the PTA group (log-rank P = .040). Cumulative incidence of mortality through 36 months was 26.6% in the DCB group compared with 30.8% in the PTA group (log-rank P = .71). CONCLUSIONS: This study demonstrated superior TLPP and ACPP with DCBs compared with PTA, with no difference in mortality through 3 years. Access circuit thrombosis was statistically significantly higher in the PTA group at 3 years.

IN.PACT AV access randomized trial: Japan cohort outcomes through 12 months.

PURPOSE: There is a lack of adjudicated and prospectively randomized published outcomes on the use of drug-coated balloons (DCB) to treat dysfunctional arteriovenous fistula in Asian patients. This post hoc subgroup analysis of 112 Japanese participants from the global IN.PACT AV Access trial reports outcomes through 12 months. MATERIALS AND METHODS: Participants were treated with DCB (n = 58) or standard non-coated percutaneous transluminal angioplasty (PTA) balloons (n = 54). Outcomes included target lesion primary patency (TLPP), access circuit primary patency, and safety. RESULTS: Through 6 months, TLPP was 86.0% (49/57) in the DCB group and 49.1% (26/53) in the PTA group (p < 0.001). Through 12 months, TLPP was 67.3% (37/55) in the DCB group and 43.4% (23/53) in the PTA group (p = 0.013). CONCLUSION: In this post hoc analysis of Japanese participants from the IN.PACT AV Access trial, participants treated with DCB had higher TLPP through 6 and 12 months compared with PTA.

IN.PACT AV Access Randomized Trial: 12-Month Clinical Results Demonstrating the Sustained Treatment Effect of Drug-Coated Balloons.

PURPOSE: To present the 12-month outcomes of the IN.PACT AV Access Study, a prospective, single-blind trial enrolling participants with obstructive de novo or restenotic native upper extremity arteriovenous dialysis fistula lesions treated with a drug-coated balloon (DCB) or percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: After successful high-pressure PTA, participants at 29 international sites were randomized 1:1 to treatment with an IN.PACT AV DCB (n = 170) or standard uncoated PTA (n = 160). Outcomes at 12 months include target lesion primary patency (TLPP), defined as freedom from clinically driven target lesion revascularization or access circuit thrombosis; access circuit primary patency; number of reinterventions; and adverse events involving the access circuit. RESULTS: At 12 months, TLPP was 63.8% (90/141) in the DCB group compared with 43.6% (61/140) in the PTA group (P < .001). The total number of reinterventions required to maintain TLPP through 360 days was 93 in the DCB group and 144 in the PTA group, with a 35.4% reduction in reinterventions when DCB was used. Access circuit thrombosis occurred in 2.9% (4/138) of the participants in the DCB group and in 6.2% (8/129) of those in the PTA group (P = .19). Time to TLPP was assessed using a multivariable analysis to identify the factors associated with loss of patency. The treatment device was the independent predictor with the largest effect, with a hazard ratio of 0.42 (95% confidence interval, 0.29-0.60; P < .001). CONCLUSIONS: TLPP was statistically significantly higher with DCBs than with standard PTA at 12 months, demonstrating the sustained and superior effectiveness of this device for the treatment of dysfunctional arteriovenous dialysis fistulae.

Use of a fluoropolymer-based paclitaxel-eluting stent for arteriovenous graft outflow vein stenosis in hemodialysis patients.

We implanted a fluoropolymer-based paclitaxel-eluting stent (FP-PES) in four hemodialysis patients with refractory outflow venous stenosis of their arteriovenous graft. The mean observation period after FP-PES implantation was 11.5 ± 4.7 months (range, 7.0-18.0 months). After FP-PES implantation, the patients were evaluated by ultrasound every 3 months. No of the patients experienced neointimal hyperplasia in the stents during the observation period, and no reintervention was performed. FP-PESs could be an attractive alternative to percutaneous transluminal angioplasty for patients with refractory outflow venous stenosis of arteriovenous hemodialysis grafts.

Multicentre Study on the Efficacy of Brachial Artery Transposition Among Haemodialysis Patients.

OBJECTIVE: Brachial artery transposition (BAT) is not a well known method for obtaining vascular access (VA) for maintenance haemodialysis. This study evaluated the outcomes of BAT. METHODS: This multicentre retrospective cohort study included 233 consecutive patients who underwent BAT between January 2012 and December 2013. The indications were inadequate vessels for obtaining VA, severe heart failure, hand ischaemia, central vein stenosis/occlusion, or a history of catheter/graft infection. The transposed brachial artery was used only for arterial inflow and other routes were used for outflow. RESULTS: BAT was successful in 227 patients, and adequate blood flow was achieved during dialysis sessions. The first successful cannulation was after a median of 18 days. BAT was performed using superficial veins as the return route in 127 patients and arteriovenous fistula (AVF) creation in 63 patients to prevent maturation failure. In 41 patients with central venous catheterisation, the transposed brachial artery was used for arterial inflow. The complications of BAT were impaired wound healing in 14 patients, including skin necrosis in two; large aneurysms in six, including a mycotic pseudo-aneurysm in one; arterial thrombosis in five; hand ischaemia in five; lymphorrhoea in four; and haematoma/bleeding in three. The transposed brachial artery was abandoned in four, three, three, and one case of arterial thrombosis/stenosis, haematoma/bleeding, skin necrosis, and large aneurysm, respectively. Access to the return routes failed in 48 cases because of vein damage caused by cannulation in 22, AVF thrombosis/stenosis in 14, catheter infection in six, and catheter occlusion in six. At two years, the primary patency rates of the transposed brachial artery and access circuit were 88% and 54%, respectively. CONCLUSION: BAT is a safe and effective technique. The patency was high for the transposed brachial artery but adequate for the access circuit. BAT can be considered for patients with an unobtainable standard arteriovenous access.

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.

Current Topics in Vascular Access: Superficialization of Arteriovenous Fistula.

BACKGROUND: An arteriovenous fistula (AVF) is considered the gold standard modality of vascular access (VA) for maintenance hemodialysis (HD) because of its superior patency, few complications, provision of high quality of life, and low risk of patient mortality. The rapid growth of the aging population and the high prevalence of comorbidities, particularly diabetes mellitus and peripheral vascular disease, in patients requiring HD inevitably deteriorate the ability to construct and maintain a conventional AVF because of these patients' insufficient vascular adaptability. Furthermore, a substantial proportion of patients undergoing HD encounter non-maturation AVF failure and mis-cannulation-related complications, resulting in the need for a temporary VA procedure. Superficialization of the AVF is an alternative form of VA that facilitates the construction of an autologous fistula by maximizing the availability of a deeply located vein. Superficialization is also utilized in VA revision to improve the cannulability of an arterialized vein. SUMMARY: Superficialization involves various approaches, including tunnel transposition, elevation, lipectomy, and liposuction. Tunnel transposition and elevation are prerequisites for construction of an alternative autologous AVF, especially a one- or two-stage transposed brachial-basilic AVF, which is widely recognized as preferential to an arteriovenous graft in patients who cannot undergo conventional AVF installation. Elevation, lipectomy, and liposuction are also employed as revisional interventions for approximating the depth of the arterialized vein and ensuring a sufficient cannulable segment in the forearm and upper arm area. More recently, modified minimally invasive techniques for each superficialization procedure have been introduced to avoid postoperative complications. Amid the growing methodological diversity of superficialization, increasingly more studies have been performed in an attempt to clarify its feasibility and outcomes. On the whole, most superficialization procedures have acceptable patency and safety profiles. However, the preferable superficialization approach varies in accordance with both the influence of the anatomic location and the inherent advantages and limitations of each procedure. Key Messages: Both careful assessment of a patient's vascular adaptability and adequate comprehension of the various superficialization modalities that are available will enable optimal establishment of an autologous AVF in individual patients. This could lead to better outcomes and more successful management of HD.

Impact of Lesion Morphology on Durability After Angioplasty of Failed Arteriovenous Fistulas in Hemodialysis Patients.

PURPOSE: To investigate if morphological patterns of arteriovenous fistula (AVF) venous lesions affect primary patency after percutaneous transluminal angioplasty (PTA). METHODS: From July 2014 to June 2015, 262 patients underwent PTA for failed AVFs. A total of 104 patients were excluded owing to (1) calcification or AVF occlusion precluding ultrasound examination, (2) central venous or arterial lesions, and (3) no follow-up, leaving 158 patients (mean age 71±12; 96 men) for analysis. More than half of the patients had one or more previous PTAs for the failed AVF. Prior to PTA the stenotic lesions were assessed using ultrasonography to determine stenotic patterns at the minimum lumen area site and to evaluate the flow volume in the brachial artery. Three stenotic patterns were identified: intimal hyperplasia (IH) stenosis (n=110), shrinking lumen stenosis (n=32), and venous valve-related stenosis (n=16). The main outcome measure was primary patency after PTA estimated using Kaplan-Meier analysis. Predictors for loss of primary patency were determined using a multivariate Cox proportional hazards model; the results are presented as the adjusted hazard ratio (HR) and 95% confidence interval (CI). RESULTS: Median follow-up after PTA was 6.3 months (interquartile range 3.3, 10.5). The 6-month primary patency estimates were 56%±5% in the IH group, 40±9% in the shrinking lumen group, and 100% in the valve stenosis group (IH vs shrinking, p=0.013; IH vs valve, p=0.003). In multivariate analysis, shrinking lumen morphology had a negative impact on primary patency (HR 2.05, 95% CI 1.25 to 3.36, p=0.005), while venous valve-related stenosis had a positive impact (HR 0.19, 95% CI 0.04 to 0.79, p=0.023). Flow volume (10-mL/min increments; HR 0.97, 95% CI 0.96 to 0.99, p=0.004) and history of PTA (HR 1.66, 95% CI 1.06 to 2.60, p=0.029) were also independently associated with primary patency after PTA. CONCLUSION: The patterns of AVF stenosis as determined by ultrasound can affect the outcome of treatment with balloon dilation.

Fistula and Survival Outcomes after Fistula Creation among Predialysis Chronic Kidney Disease Stage 5 Patients.

BACKGROUND: Most guidelines recommend the creation of arteriovenous fistula (AVF) in patients with chronic kidney disease (CKD) stage 4. However, an increasing number of studies suggest that early AVF creation leads to high rates of AVF failure and death before dialysis commencement. Only the Japanese guideline recommends AVF creation at CKD stage 5; however, no data are available regarding access-related outcomes at this stage. METHOD: This was a multicenter cohort study involving Japanese CKD stage 5 patients who underwent preemptive AVF creation from 2009 to 2013. The primary outcome was unnecessary AVF creation, defined as death before requiring dialysis or AVF failure before dialysis commencement. The secondary outcome was dialysis commencement. The associations with candidate predictors and the outcomes were examined. RESULTS: A total of 303 patients were registered. Four cases of death before dialysis and 13 cases of AVF failure before dialysis commencement were observed. A total of 283 patients who advanced to dialysis were found to have functional AVFs. The cumulative incidences of unnecessary AVF creation and dialysis commencement at 1 year were 4.8 and 89.3%, respectively. Competing risk regression analyses showed that age ≥75 years (subhazard ratio [SHR] 3.12, 95% CI 1.20-8.09) and female gender (SHR 3.31, 95% CI 1.20-9.09) were associated with unnecessary AVF creation. CONCLUSIONS: A low incidence of unnecessary AVF creation was revealed among Japanese patients who received AVF at CKD stage 5. These results may help clarify the natural history of unnecessary AVF creation for other countries reformatting their guidelines regarding late vascular access creation.

Retrograde Approach Using Surgical Cutdown Technique for Limb Salvage in a Case of Critical Limb Ischemia With Severely Calcified Tibial Occlusive Disease.

We here report a successful angioplasty for tibial artery occlusion using direct tibial puncture and subsequent retrograde approach under surgical cutdown technique. An 82-year-old man with ulcer/gangrene in first and second digits was referred to our hospital for endovascular therapy (EVT) of lower extremity ischemia. Diagnostic angiogram revealed anterior tibial artery (ATA) occlusion with severe calcification. Subintimal angioplasty was attempted using a 0.014-inch hydrophilic guidewire but was unsuccessful. A retrograde approach was subsequently attempted for ATA recanalization. However, because of severe calcification of dorsal pedis artery (DPA), percutaneous distal puncture was also unsuccessful. Direct puncture under surgical cutdown technique for DPA was subsequently performed and was successful. A 0.014-inch hydrophilic wire was advanced in retrograde fashion across the ATA occlusion and was used to access the microcatheter positioned at the proximal ATA via antegrade approach. Angioplasty of the ATA occlusion was performed using a 2.5-/3.0-mm tapered balloon. Completion angiogram revealed restoration of flow without dissection. Skin perfusion pressure was dramatically improved. Complete wound healing was achieved 5 months after EVT.

Predicting loss of patency after forearm loop arteriovenous graft.

OBJECTIVE: Although arteriovenous grafts (AVGs) for dialysis access have been applied to patients who were poor candidates for an arteriovenous fistula, durability after AVGs has been clinically suboptimal. This retrospective study investigated whether forearm AVGs based on radial artery inflow would have superior patency to those with brachial artery inflow and evaluated the operative predictors for loss of patency after AVG. METHODS: This multicenter retrospective study included 156 upper limbs in 150 consecutive patients (50% male; age, 70.5 ± 12.8 years) who underwent forearm loop AVG formation from January 2010 to October 2013. The outcome measures were the primary and secondary functional graft patency rates and factors related to primary patency. Primary and secondary patency of AVGs was evaluated by Kaplan-Meier analysis, and predictors for loss of primary patency of AVGs were determined using a Cox proportional hazards model. RESULTS: The median observation period was 10 months (interquartile range, 6-18 months). The 1-year primary patency rate was 32.4%, and the secondary patency rate was 83.4%. Use of the radial artery as the inflow arteriovenous anastomosis (hazard ratio, 0.56; 95% confidence interval, 0.30-0.99) was independently associated as an operative predictor for primary patency after AVG. The primary patency rate was significantly different between radial artery inflow and brachial artery inflow at 1 year (53.8% vs 24.4%; P = .032). CONCLUSIONS: Radial artery selection as inflow artery was independently associated with primary patency after AVG.

Percutaneous transluminal angioplasty in Japan: five-center investigation.

PURPOSE: Percutaneous transluminal angioplasty (PTA) is the first-line treatment for vascular access stenosis. To our knowledge, multicenter clinical research of PTA has not been reported in Japan. We examined the efficacy and safety of PTA for arteriovenous fistula (AVF) and arteriovenous graft (AVG) in five centers of Japan. METHODS: Three hundred cases of angioplasty for AVF and 300 for AVG were examined in three centers each. A hundred consecutive patients from each center who underwent PTA for AVG or AVF prior to March 2014 and met the inclusion criteria were searched retrospectively. Primary patency rates were estimated using the Kaplan-Meier method. RESULTS: The mean age was 69.3 ± 11.2 years in the AVF group and 70.2 ± 11.9 years in the AVG group. The anatomical success rates were 51.7% (155 of 300) in the AVF group and 72.0% (216 of 300) in the AVG group. The clinical success rates were 99.7% (299 of 300) in the AVF group and 100% (300 of 300) in the AVG group. A total of 25 complications (4.17%) were encountered in both groups including one major complication (0.17%). The primary patency was 99.0% at 1 month, 87.9% at 3 months and 51.7% at 6 months in the AVF group, and 96.0% at 1 month, 64.8% at 3 months and 20.4% at 6 months in the AVG group. CONCLUSIONS: The clinical success rate of PTA in five centers was relatively high and a major complication rate was only 0.17%. However, anatomical success rates were low comparing with the previous studies and the primary patency rates were inferior to the past data.

Superficialization of brachial artery as effective alternative vascular access.

OBJECTIVE: The Japanese Society for Dialysis Therapy recommends superficialization of the brachial artery (BA) as an alternative vascular access (VA) technique in patients for whom a conventional internal shunt (arteriovenous fistula [AVF] or arteriovenous graft) cannot be created. Although 2% to 3% of Japanese hemodialysis patients undergo this procedure, it is not well recognized worldwide. We report here our experience with the procedure, as well as indications, durability, and morbidity. METHODS: The technique involves exposure of the BA and ligation of the side branches, then fixing it beneath the skin at the upper arm. Cannulation of the BA is performed 2 weeks or more after surgery, and it is used as an outflow route, with any vein in an upper extremity utilized for blood return, including the hand if sites in the arm are not accessible. We retrospectively reviewed our cases of superficialization of the BA for VA. RESULTS: From 2005 through 2008, a total of 24 patients (11 females [46%]; average age, 69 years [range, 39-84 years]) underwent superficialization of the BA, of whom eight (33%) had diabetes. The indications were (1) impaired cardiac function (n = 13); (2) no other prospect for AVF or patient refused prosthetic graft implantation (n = 5); (3) severe upper extremity arterial disease or ischemic steal syndrome requiring AVF closure (n = 3); (4) venous hypertension with central vein occlusion (n = 2); and (5) repeated AVF thrombosis due to heparin-induced thrombocytopenia (n = 1). The mean follow-up period was 28 months. Serious complications were seen in one patient with an infected pseudoaneurysm formation associated with a BA puncture, which necessitated BA ligation, while two patients required an aneurysmectomy with reconstruction and one had occlusion of the superficialized BA, though no clinical symptoms of hand ischemia developed. We also had difficulty finding a vein for blood return in five patients. The rate of superficialized BA patency as a functioning VA was 95% and 66% at 1 and 3 years, respectively. CONCLUSIONS: Superficialization of the BA was found to be a simple and safe technique, with acceptable durability and complication rate in selected Japanese hemodialysis patients. We consider that this shuntless VA permits adequate blood flow and has theoretical advantages for some patients, particularly those with impaired cardiac function, though the availability of a return vein is a prerequisite for a functioning VA.