Association between End-Stage Renal Disease and Major Adverse Limb Events after Peripheral Vascular Intervention.

PURPOSE: To examine the effect of end-stage renal disease (ESRD) on the likelihood of major adverse limb events (MALEs) in patients with Rutherford Category 4-6 critical limb ischemia (CLI) who underwent percutaneous vascular intervention (PVI). MATERIALS AND METHODS: Two contemporaneous cohorts of patients who underwent PVI for symptomatic CLI from 2012 to 2022, differing in ESRD status, were matched using propensity score methods. This database identified 628 patients who underwent 1,297 lower extremity revascularization procedures; propensity score matching yielded 147 patients (180 limbs, 90 limbs in each group). Kaplan-Meier and Cox proportional hazard analyses were used to assess the effect of ESRD status on MALEs, stratified into major amputation (further stratified into above-knee amputation and below-knee amputation [BKA]) and reintervention (PVI or bypass). RESULTS: After PVI, 31.3% of patients in the matched cohorts experienced a MALE (45.7% ESRD vs 18.2% non-ESRD), and 15.6% experienced a major amputation (27.1% ESRD vs 5.2% non-ESRD). Cox proportional hazards analysis revealed that ESRD was an independent predictor of MALE (hazard ratio [HR], 3.15; 95% CI, 1.58-6.29; P = .001), major amputation (HR, 7.00; 95% CI, 2.06-23.79; P = .002), and BKA (HR, 7.56; 95% CI, 1.71-33.50; P = .008). CONCLUSIONS: ESRD is strongly predictive of MALE and major amputation risk, specifically BKA, in patients undergoing PVI for Rutherford Category 4-6 CLI. These patients warrant closer follow-up, and new methods may become necessary to predict and further reduce their amputation risk.

Percutaneous Management of Dialysis Access Steal Syndrome: Interventions and Outcomes from a Single Institution's 20-Year Experience.

PURPOSE: To determine safety and effectiveness of percutaneous interventions performed by interventional radiologists at a single institution over 2 decades in patients with dialysis access steal syndrome (DASS). MATERIALS AND METHODS: A retrospective review of fistulograms from 2001 to 2021 (N = 11,658) was performed. In total, 286 fistulograms in 212 patients with surgically created dialysis accesses met inclusion criterion of fistulography for suspected DASS. Chart review collected data regarding patient demographics, comorbidities, access characteristics, fistulography findings, intervention(s) performed, and outcomes. Procedures with and without DASS intervention were compared. Odds ratios (ORs), adjusted for age, sex, comorbidities, access characteristics, and multiple within-patient events, were calculated using logistic regression to determine associations between steal intervention status and outcome variables: (a) major adverse events, (b) access preservation, and (c) follow-up surgery. A percutaneously treatable cause of DASS was present in 128 cases (45%). Treatment of DASS lesions was performed in 118 cases. Fifteen embolizations were also performed in patients without DASS lesions. RESULTS: Technical success of DASS interventions, defined by the Society of Interventional Radiology (SIR) reporting standards, was 94%; 54% of interventions resulted in DASS symptom improvement at a median follow-up of 15 days. Patients with steal intervention had 60% lower odds of follow-up surgery (OR, 0.4; P = .007). There was no difference in major adverse events (P = .98) or access preservation (P = .13) between groups. CONCLUSIONS: In this retrospective cohort study, approximately half of DASS fistulograms revealed a percutaneously treatable cause of steal. Over half of DASS interventions resulted in symptomatic relief. Percutaneous intervention was associated with lower odds of follow-up surgery without compromising access preservation.

Synthesis of a DNA-Encoded Macrocyclic Library Utilizing Intramolecular Benzimidazole Formation.

Macrocycles occupy chemical space "beyond the rule of five". They bridge traditional bioactive small molecule drugs and macromolecules and have the potential to modulate challenging targets such as PPI or proteases. Here we report an on-DNA macrocyclization reaction utilizing intramolecular benzimidazole formation. A 129-million-member macrocyclic library composed of a privileged benzimidazole core, a dipeptide sequence (natural or non-natural), and linkers of varying length and flexibility was designed and synthesized.

Diagnosis and Treatment of Nonmaturing Fistulae for Hemodialysis Access via Transradial Approach: A Case-Control Study.

PURPOSE: To compare outcomes of transradial access for endovascular treatment of nonmaturing hemodialysis fistulae compared to brachial arteriography followed by unidirectional or bidirectional fistula access for intervention. MATERIALS AND METHODS: In this institutional review board-approved, retrospective, case-control study, 56 consecutive patients with nonmaturing arteriovenous fistulae underwent percutaneous intervention between 2015 and 2018. The transradial group (n = 28) underwent radial artery access for diagnostic fistulography and intervention. The control group (n = 28) underwent retrograde brachial artery access for fistulography followed by unidirectional/bidirectional fistula access for intervention. Both groups had similar demographics, fistula characteristics, and stenosis locations. RESULTS: Fewer punctures were required in the transradial group compared to controls (1.2 vs 2.4, P < .0001), and procedure time was shorter (64.9 vs 91.3 minutes, P = .0016). Anatomic, technical, and clinical success rates trended higher in the transradial group compared to controls (93% vs 86%, 96% vs 89%, and 82% vs 64%, respectively). Nonmaturation resulting in fistula abandonment was lower in the transradial group (3.7% vs 25%, P = .025). Primary unassisted patency at 3, 6, and 12 months was 77.1% ± 8.2%, 73.1% ± 8.7%, and 53.3% ± 10.6% in the transradial group, respectively, and 63.0% ± 9.3%, 55.6% ± 9.6%, and 48.1% ± 9.6% in the control group, respectively (P = .76). Primary assisted patency at 12 months was 92.3% ± 5.3% in the transradial group compared to 61.8% ± 9.6% at 12 months in the control group (P = .021). No major complications occurred. Minor complications were lower in the transradial group than in the control group (14% vs 39%, P = .068). CONCLUSIONS: Treatment of nonmaturing fistulae via a transradial approach was safe, improved midterm patency, and was associated with lower rates of fistula abandonment.

Endovascular Therapy for Below-the-Elbow Arterial Disease: An Initial Single-Center Experience.

Purpose: To evaluate the technical success, clinical success, and complication rates of endovascular revascularization for below-the-elbow (BTE) peripheral artery disease. Materials and Methods: A retrospective review was performed of 19 patients (mean age 63 years; 12 men) with critical hand ischemia (CHI) who underwent 25 interventions in 19 arms between October 2010 and June 2017. Access was attained using 4-F or 5-F sheaths via antegrade brachial, retrograde radial, or fistula/graft access routes depending on the target vessel. A 0.018-inch hydrophilic microwire was used for intimal or subintimal recanalization. Angioplasty was performed over a 0.014-inch guidewire using low-profile balloons. The primary endpoint of the study was technical success, defined as successful lesion crossing/dilation, with residual stenosis <30%. Clinical success referred to improvement in pain and/or steal symptoms. Results: Technical success was achieved in 88% (22 of 25 procedures), with no significant difference in outcome associated with indications or baseline vessel disease. Complications occurred in 6 cases, of which 5 were minor and 1 was major. Clinical success was achieved in 12 of 14 patients with available follow-up; 5 of 7 patients with ulcers experienced wound healing. Conclusion: Endovascular revascularization for BTE occlusive disease is an effective and safe strategy for treating CHI.

Outcomes of a Polytetrafluoroethylene Hybrid Vascular Graft with Preloaded Nitinol Stent at the Venous Outflow for Dialysis Vascular Access.

BACKGROUND: To evaluate outcomes and patency of arteriovenous grafts (AVGs) created using Gore hybrid vascular grafts in hemodialysis patients with limited venous outflow or challenging anatomy. MATERIALS AND METHODS: A retrospective review was performed in two academic centers of all patients between July 2013 and December 2016 who underwent surgical AVG creation using a Gore hybrid vascular graft in a brachial artery to axillary configuration. Patient characteristics and comorbidities as well as graft patency, function, and subsequent need for percutaneous interventions were recorded. RESULTS: Forty-six patients including 30 females (65.2%) and 16 males (34.8%) with a mean age of 63 ± 13 years were identified. The most common indications for a hybrid vascular graft were limited surgical accessibility and/or revision of existing AVG due to severe stenotic lesions at the venous outflow in 33 patients (72%). One-year primary unassisted and assisted patency rates were 44 ± 8% and 54 ± 8%, respectively, compared with 1-year secondary patency rate of 66 ± 8%. The rate of percutaneous interventions to maintain graft function and patency was approximately one intervention per graft per year. CONCLUSIONS: Access created with the hybrid vascular graft in a brachial-axillary (brachial artery to axillary vein) configuration is an acceptable option for patients with limited venous outflow reserve and challenging anatomy. Twelve-month primary and secondary patency rates and need for percutaneous interventions were comparable to traditional AVGs.

Initial Clinical Experience: Symmetric-Tip Dialysis Catheter with Helical Flow Characteristics Improves Patient Outcomes.

PURPOSE: To report preliminary clinical experience with a new symmetric-tip dialysis catheter compared with a conventional split-tip catheter. MATERIALS AND METHODS: Over a 5-month period, patients requiring a tunneled catheter for hemodialysis or undergoing exchange of a dysfunctional dialysis catheter at a tertiary academic medical center were retrospectively analyzed. Patients underwent placement of a VectorFlow or Ash Split Cath catheter at the discretion of the inserting interventional radiologist. Patient demographics, catheter patency, mean blood flow rate, and arterial and venous pressures were compared according to catheter type. Catheter failure was analyzed based on clinical and anatomic variables by using a multivariate Cox proportional-hazards model. RESULTS: A total of 33 VectorFlow and 46 Ash Split Cath catheters were placed. Patients in the VectorFlow group had significantly higher body mass index (P = .013) and Charlson Comorbidity Index (P = .049), as well as more non-internal jugular vein placements. At 120 days, 89% of VectorFlow catheters remained functional, compared with 45% of Ash Split Cath catheters (P = .046). The VectorFlow catheter was associated with 16% lower arterial pressures during dialysis (P = .009); mean blood flow rate was equivalent. On multivariate analysis, the risk of catheter failure was 13.3 times higher in the Ash Split Cath group compared with the VectorFlow group (P = .004). Left-sided catheters were also predictive of catheter failure (relative risk = 5.5; P = .02). CONCLUSIONS: The VectorFlow catheter was associated with a significant increase in intervention-free catheter patency compared with the Ash Split Cath catheter, with equivalent flow at lower arterial pressures during dialysis.

Outcomes of single-stage compared to two-stage basilic vein transposition fistulae.

Basilic vein transposition (BVT) fistulae are increasing in prevalence in the United States. We examined outcomes of BVT fistulae created in a single stage compared to those created in two stages. Prospective QA databases identified a consecutive cohort of 144 patients with BVT fistulae. Of these, 42% were created in one stage and 58% in two stages. Fistula maturation rates, mean time to fistula use and intensity of percutaneous interventions were compared; patency rates were compared from time of first intervention. Maturation rates (including assisted maturation) were 90% among 1-stage and 75% among 2-stage BVT (p = 0.02). Mean time to initiation of fistula use was 142 days (1-stage) and 146 days (2-stage) (p = 0.92). Intensity of percutaneous interventions was 1.84/patient-year of dialysis (PYD) (1-stage) and 2.15/PYD (2-stage) (p = 0.57). Secondary patency at 1, 2, 3, and 4 years for 1-stage BVT was 86%, 75%, 69%, and 57%; secondary patency at 1, 2, 3, and 4 years for 2-stage BVT was 76%, 71%, 49%, and 25%, respectively (p = 0.12). BVT creation in two stages confers only a modest reduction in maturation rates and secondary patency and therefore should be considered over a synthetic graft in patients with basilic veins deemed inadequate for 1-stage BVT.

Radiofrequency guidewire-facilitated recanalization of chronic thoracic central venous occlusions in hemodialysis patients.

PURPOSE: To assess the outcome and safety of radiofrequency (RF) wire recanalization in patients with end-stage renal disease (ESRD) and chronic central venous occlusions (CVO). MATERIALS AND METHODS: A retrospective review of ESRD patients who underwent RF-wire recanalization of symptomatic chronic thoracic CVO from January 2017 to August 2022 yielded 20 patients who underwent 21 procedures. All patients had undergone at least one prior unsuccessful attempt at central venous recanalization using conventional catheter-based techniques. Technical success was defined by the ability to cross the CVO using RF-wire recanalization enabling endovascular treatment. Access circuit patency was evaluated based on follow-up imaging and symptomatic improvement. RESULTS: Radiofrequency wire recanalization was successful in 17/21 procedures (81%) with all patients (100%) reporting resolution of arm ± facial swelling. Three major complications occurred (14%): two hemothoraces and one hemopericardium. Medial stent diameter was 13 mm (range, 9-14 mm). Mean duration of hospital stay was 2 days ± 3 days. Mean procedure time was 158 ± 46 min with a mean fluoroscopy time of 31.7 ± 16.3 min. Primary unassisted patency at 6 and 12 months was 94 ± 6% and 85 ± 10%, respectively. Additional interventions resulted in significantly increased stent graft patency (P = 0.006). CONCLUSION: Radiofrequency wire-enabled recanalization of CVO in symptomatic dialysis patients has a high rate of technical success with resolution of arm and facial swelling and resumed use of the ipsilateral dialysis access. Although a superior safety profile was seen than with needle-based techniques such as sharp recanalization, major complications were not infrequent indicating that this RF-wire procedure should be performed in centers equipped to manage central venous perforations.

Outcomes of percutaneous interventions in transposed hemodialysis fistulas compared with nontransposed fistulas and grafts.

PURPOSE: To compare postpercutaneous intervention outcomes of autogenous venous-transposition arteriovenous fistulas (AVFs) versus those of autogenous nontransposed AVFs (nAVFs) and prosthetic arteriovenous grafts (AVGs). MATERIALS AND METHODS: A total of 591 hemodialysis accesses (195 transposed AVFs [tAVFs], 205 nAVFs, 191 AVGs) in 522 patients (278 male; mean age, 57 y; range, 15­91 y) underwent percutaneous transluminal angioplasty (PTA) and/or mechanical thrombectomy (ie, declotting). Access characteristics, surgical history, percutaneous interventions, postinterventional primary and secondary access patency, and follow-up data were collected. Cox proportional-hazards regression analyses, Fisher exact tests, and χ2 tests were performed. RESULTS: Mean follow-up period was 32 months. Mean access ages at initial percutaneous intervention were 260 days (tAVF), 206 days (nAVF), and 176 days (AVG; P < .01). One-year postinterventional primary patency (PIPP) rates were 25% (tAVF), 24% (nAVF), and 14% (AVG). One-year postinterventional secondary patency (PISP) rates were 77% (tAVF), 61% (nAVF), and 63% (AVG). Median PIPP durations were 138 days (tAVF), 121 days (nAVF), and 79 days (AVG; P = .0001). Median PISP durations were 1,076 days (tAVF), 783 days (nAVF), and 750 days (AVG; P = .019). Total interventions needed to maintain PISP were 2.4 (tAVF), 1.3 (nAVF), and 3.2 (AVG) per patient-year (P < .001), which included 1.9, 1.2, and 1.4 PTAs (P < .01) and 0.45, 0.15, and 1.8 declotting procedures, respectively (P < .001). CONCLUSIONS: Based on the number of percutaneous interventions needed to maintain PISP, these results confirm the current Dialysis Outcomes Quality Initiative access preference of nAVFs before tAVFs before AVGs. tAVFs offered superior postinterventional outcomes than AVGs. With additional interventions, tAVFs could even outperform nAVFs in terms of PISP.

Arteriovenous fistula creation using the Optiflow vascular anastomosis device: a first in man pilot study.

Although arteriovenous fistulae are the preferred form of dialysis vascular access they continue to have significant problems with maturation failure. The Optiflow device is a sutureless anastomotic conduit which could potentially reduce surgical time and also standardize the surgical procedure. We report herein on the "First in Man" experience with the Optiflow device.

Surgical Referral for Hemodialysis Access Maintenance.

Hemodialysis access is the lifeline for end-stage renal disease patients. However, dialysis access is associated with a host of complications, including thrombosis, recurrent stenosis, infection, aneurysmal changes and bleeding. Although endovascular therapy remains the first-line treatment owing to its less invasive nature, there are certain situations where surgical referral is recommended or even necessary. Regardless, management of dialysis access complications requires a multidisciplinary approach. Interventional radiologists should be familiar with the appropriate timing for surgical referral to better serve the complex patient population.

One Reaction Served Three Ways: The On-DNA Ugi 4C-3C Reaction for the Formation of Lactams.

Developing new on-DNA reactions is paramount to the development of new encoded libraries in the pursuit of novel pharmaceutical lead compounds. Lactam-containing molecules have been shown to be effective in a wide range of therapeutic areas and therefore represent a promising target for further investigation by DNA-encoded library screening. In pursuit of this motif, we report a novel method for the introduction of lactam-containing structures onto a DNA headpiece through the Ugi four-center three-component reaction (4C-3CR). This novel method is successful in three different approaches to give unique on-DNA lactam structures: on-DNA aldehyde coupled with isonitriles and amino acids; on-DNA isonitrile coupled with aldehydes and amino acids; and on-DNA isonitrile coupled with amines and acid aldehydes.

Dialysis Access-Associated Steal Syndrome and Management.

Dialysis-associated steal syndrome (DASS) occurs in 1-8% of hemodialysis patients with arteriovenous (AV) access. Major risk factors include use of the brachial artery for access creation, female sex, diabetes, and age > 60 years. DASS carries severe patient morbidity including tissue or limb loss if not recognized and managed promptly, as well as increased mortality. Diagnosis of DASS requires a directed history and physical exam supported by non-invasive testing. Prior to definitive therapy, detailed arteriography, fistulography, and flow measurements are performed to delineate underlying etiologies and guide management. To optimize success, DASS treatment should be individualized according to access location, underlying vascular disease, flow dynamics, and provider expertise. Possible causes of DASS include extremity inflow or outflow arterial occlusive disease, high AV access flow rate, and reversal of distal extremity arterial blood flow; DASS may also exist without any of the prior features. Depending on the DASS etiology, various endovascular and/or surgical interventions should be considered. Regardless, in the majority of patients presenting with DASS, access preservation can be achieved.

Association between anaesthesia type and arteriovenous fistula maturation.

Background: Whereas general anaesthesia is commonly used for haemodialysis fistula creation, regional or local anaesthesia has been posited to lead to better fistula maturation outcomes. We sought to measure the association between anaesthesia type and arteriovenous fistula maturation. Methods: We performed a secondary analysis of data from the Hemodialysis Fistula Maturation study, a multicentre prospective cohort study of advanced chronic kidney disease patients who underwent single-stage upper extremity fistula creation between 2010 and 2013. We evaluated the relationship between anaesthesia type and unassisted (without maturation-facilitating interventions) or overall (unassisted or assisted) fistula maturation using multivariable logistic regression. Results: Among 602 participants, 336 (55.8%) received regional/local anaesthesia and 266 (44.2%) received general anaesthesia. Unassisted maturation occurred in 164/309 patients (53.1%) after regional/local vs 91/226 patients (40.3%) after general anaesthesia (P=0.003). After adjustment for patient factors and fistula type, regional/local anaesthesia was associated with greater odds of unassisted maturation than general anaesthesia (odds ratio 1.72, 95% confidence interval 1.24-2.39; P=0.001). However, after further adjustment for clinical centre fixed effects, odds of unassisted maturation did not differ by anaesthesia type (odds ratio 1.03, 95% confidence interval 0.78-1.36; P=0.830). Similar findings were observed for overall maturation and composite endpoints accounting for potential survivorship bias. Conclusions: Regional/local anaesthesia was associated with increased odds of fistula maturation when adjusting for patient factors and fistula type. However, this association did not persist after adjusting for centre fixed effects. Future research is needed to better understand the relationship between anaesthesia type and centre factors to optimise outcomes after fistula surgery.

Outcomes of thrombectomy procedures performed in hemodialysis grafts with early failure.

PURPOSE: Percutaneous declotting is usually not offered for hemodialysis access grafts clotting < 30 days after placement because of concerns regarding safety of percutaneous transluminal angioplasty in fresh anastomoses, potential need for surgical correction of the underlying cause, and poor outcomes. The authors sought to determine acute and long-term outcomes of declotting of grafts with early failure. MATERIALS AND METHODS: Of 860 percutaneous mechanical thrombectomies performed between July 2001 and June 2007, 23 were performed in grafts < 30 days after initial placement. In addition, 16 percutaneous thrombectomies performed in grafts 31-60 days after placement were identified. Data collected included medical history, graft characteristics, immediate technical and clinical success, complications, and subsequent graft patency and survival. Kaplan-Meier analysis compared outcomes in grafts < 30 days (U30) versus those 31-60 days (U60) old. RESULTS: There was no difference between the U30 and U60 groups in primary patency (13 vs 19 days, respectively, P = 0.17) or in postintervention access patency (38 vs 189 days, respectively, P = 0.63). A strong trend toward shorter secondary patency in U30 grafts was observed (17 vs 73 days, P = 0.06). Underlying lesions not amenable to percutaneous treatment were found in 62% of U30 grafts and 33% of U60 grafts (P = 0.18). Neither group achieved the K/DOQI Guidelines' recommended 85% technical success or 40% 90-day primary patency; in the U30 group it was 0% and in the U60 group 17%. CONCLUSIONS: Percutaneous declotting of grafts yields poor outcomes, well below the K/DOQI threshold not only within 30 days but also within 60 days of placement.

SNAr and C-H Amination of Electron Rich Arenes with Pyridine as a Nucleophile Using Photoredox Catalysis.

This report describes the development of two photocatalytic methods for the pyridination of electron rich arenes. First, an SNAr-type reaction between aryl halides and pyridine is developed and optimized. This transformation affords selective substitution of C(sp2)-halogen over C(sp2)-OR bonds to afford arylpyridinium products under anaerobic conditions. Under complementary aerobic conditions, analogous substrates are shown to undergo oxidative C(sp2)-H pyridination.

Safety and Efficacy of Arterial Closure Devices Following Antegrade Femoral Access: A Case-Control Study.

PURPOSE: Vascular closure device (VCD) use following antegrade femoral access may present unique challenges relative to retrograde access. We retrospectively compared safety and efficacy of these devices between antegrade and retrograde patient cohorts undergoing percutaneous intervention. MATERIALS AND METHODS: Over a 5-year period, a consecutive series of 107 limbs in 84 patients underwent VCD arteriotomy closure following percutaneous revascularization using an antegrade approach (VCD-A). Device deployment success rates, time to ambulation, and complication rates were compared to a contemporaneous control group of 401 limbs in 305 patients who underwent closure following retrograde access (VCD-R) during revascularization or embolization procedures. RESULTS: Closure was attempted in VCD-A using 53 StarClose, 35 Perclose, and 19 Angio-Seal devices. Hemostasis (without supplemental manual compression) was achieved in 86/107 (80.4%) limbs. Closure was attempted in VCD-R using 215 StarClose, 119 Perclose, and 67 Angio-Seal devices with hemostasis in 357/401 (89.0%) limbs. Device deployment failure occurred in 7/107 (6.5%) of VCD-A and 20/401 (5.0%) of VCD-R (P = .52), independent of specific device type. Femoral pseudoaneurysm developed in 1/107 and 1/401 of VCD-A and VCD-R (P = .31), and minor hematoma developed in 3/107 and 8/401 of the VCD-A and VCD-R (P = .61). Mean time to ambulation was 204.1 minutes in VCD-A and 204.8 minutes in VCD-R (P = .97). CONCLUSION: Antegrade femoral closure was associated with high rates of technical success and low complications, similar to retrograde closure. Time to ambulation was the same in both groups despite higher heparin doses in the antegrade patients.

Incidence and management of percutaneous transluminal angioplasty-induced venous rupture in the "fistula first" era.

PURPOSE: Percutaneous transluminal angioplasty (PTA)-induced venous rupture is a common complication of hemodialysis access interventions. The authors sought to determine if venous rupture rates and management differed between grafts and fistulas, and in the fistula subset, between transposed and nontransposed fistulas. MATERIALS AND METHODS: Patients experiencing venous rupture during hemodialysis PTA over a 5-year period were identified. Of 1,985 hemodialysis interventions, 75 ruptures occurred in 69 patients (46 women) with a mean age of 63 years (range, 31-88 y). Rupture rates, proportion of successful treatments, and treatment type and number (ie, balloon tamponade, stent, covered stent) were determined. RESULTS: Rupture was more common in fistulas overall (5.6%, 39 of 693) compared with grafts (2.8%, 36 of 1,292; P = .002), in transposed (10.7%, 20 of 187) compared with nontransposed fistulas (3.8%, 19 of 506; P = .001), and in transposed fistulas compared with grafts (P = .0001). There was no significant difference between nontransposed fistulas and grafts. Treatment success (ie, resolution of extravasation) was the same among groups: 69% (27 of 39) in fistulas overall, 70% (14 of 20) in transposed fistulas, 68% (13 of 19) in nontransposed fistulas, and 72% (26 of 36) in grafts. There was a greater need for stents in grafts (38.9%, 14 of 36) compared with fistulas (12.8%, five of 39; P = .003). CONCLUSIONS: PTA-induced rupture is more common in fistulas than grafts, and this effect seems nearly entirely driven by transposed fistulas. Although rupture treatment in fistulas of all types yielded similar success to grafts, and graft ruptures were more difficult to treat than fistula ruptures, the high rupture rates in transposed fistulas attest to the increased difficulty of treating this subset of fistulas.