Endovascular creation of hemodialysis arteriovenous fistulae: the current status and future perspective-a literature review.

Background and Objective: End-stage renal disease (ESRD) is increasingly prevalent among Americans. Traditionally, the gold standard of dialysis fistulae creation is surgical arteriovenous fistulae (AVF), which is preferred over central venous catheter (CVC) and arteriovenous graft (AVG). However, it is associated with many challenges, particularly its high primary failure rate, which is partially attributed to neointimal hyperplasia. Endovascular creation of arteriovenous fistulae (endoAVF) is a recently emerging method, and is thought to circumvent many of the surgical challenges. It is theorized to reduce the peri-operative trauma to the vessel, thus reducing the amount of neointimal hyperplasia. In this article, we aim to review the current status and future perspectives of endoAVF. Methods: An electronic search was performed on MEDLINE and Embase to identify relevant articles from 2015 to 2021. Key Content and Findings: The initial trial data has been promising, resulting in the increased adoption of endoAVF devices in clinical practice. Further, short- and mid-term data has shown that endoAVF has been associated with good maturation rate, re-intervention rate, primary and secondary patency rates. In comparison to historical surgical data, endoAVF has been shown to be comparable in certain aspects. Lastly, endoAVF has been used in an increasing range of clinical applications, including wrist AVF and two-stage transposition procedure. Conclusions: Although current data has been promising, endoAVF is associated with a host of unique challenges, and the current data has mostly been derived from selective patient population. Further studies are required to further assess its usefulness and its role in the dialysis care algorithm.

Iatrogenic Renal Artery Injury in 90 Cases: Arteriographic Findings and Outcomes after Embolization for Bleeding.

PURPOSE: To evaluate differences in arteriographic findings and outcomes after embolization among patients with a suspected iatrogenic renal arterial injury (IRAI). MATERIALS AND METHODS: Patients at the authors' institution who underwent renal arteriography for suspected IRAIs after partial nephrectomy, biopsy, or percutaneous access over a 20-year period were included. Records, imaging, and outcomes were reviewed. Data analysis was performed using the Fisher exact or Kruskal-Wallis test. RESULTS: Ninety arteriograms were performed on 83 patients after partial nephrectomy (n = 32), biopsy (n = 27), or percutaneous access (n = 24), including for nephrostomy/ureterostomy and stone removal. The median number of days between the index procedure and arteriogram was highest (15 days) after partial nephrectomy and lowest (5 days) after biopsy (P = .0001). Embolization was performed during 76% of arteriograms. If prearteriographic imaging showed positive results for IRAIs, embolization was performed in 67% versus 33% if imaging showed negative results (P = .005). The transfusion rate was higher after biopsy than after partial nephrectomy or percutaneous access (P = .002). Acute kidney injury after arteriogram occurred in 7% of patients; however, all returned to baseline by 1 week. CONCLUSIONS: Despite the different mechanism of IRAIs in partial nephrectomy, biopsy, and percutaneous access, arteriographic findings and outcomes were overall similar among groups. Prearteriographic imaging can help identify IRAIs but cannot supersede the clinical judgment regarding indication for embolization. IRAIs can present acutely or after a long interim, although patients who underwent biopsy presented earlier and more frequently required a blood transfusion. IRAIs can be treated with embolization without permanent deleterious effects on renal function.

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.

Complications related to totally implantable venous access devices in children and adults following lung transplantation.

INTRODUCTION: Totally implantable venous access devices (TIVADs) are the preferred devices for patients with advanced lung disease who require long-term venous access. The primary purpose of this study was to describe the natural history of TIVADs left in place at the time of transplant. METHODS: This multicenter retrospective cohort study evaluated pediatric and adult lung transplant recipients from 5/5/2005 to 12/31/17 with pretransplant TIVAD. Incident rates (IR) for infectious and mechanical complications were calculated. Poisson regression models were used to identify TIVAD characteristics associated with complications. RESULTS: Of 1253 transplant recipients, 82 (6.5%) had pretransplant TIVAD. Five (6.1%) TIVADs were removed at transplantation. Fifty-five (67.1%) TIVADs were eventually removed, most commonly because they were no longer required (50.9%) or because of infection (25.5%). Overall incident rates (IR) of infectious or mechanical complications were 0.33 and 0.14, respectively. The IR of infection was highest within one year of transplant, particularly during the index hospitalization (IR = 1.67). Youngest tertile (<22 years) had the lowest incident rate ratio of TIVAD infections (IRR = 0.22). CONCLUSION: Although TIVAD complication rates in lung transplant recipients are similar to non-transplant and other immunocompromised patients, TIVAD removal at transplant or within the first post-transplant year may minimize the risk of TIVAD infections.

Fistulography of a Patent Hemodialysis Access: When Not to Treat and Implications for Establishing a Nontreatment Rate.

PURPOSE: To establish a rate of nonintervention in patients referred for hemodialysis access fistulography and to report clinical and fistulographic variables associated with nonintervention. MATERIALS AND METHODS: Encounters for fistulography were reviewed from 2001 to 2016 to determine annual rates of nontreatment over 15 years. Next, an access database was used to retrospectively identify patients undergoing fistulography from 2010 to 2016. Patients who underwent fistulography without intervention (angioplasty or stent placement) served as the nontreatment group (NTG; n = 76). Patients who underwent fistulography with intervention served as the control group (CG; n = 77). Patients with thrombosed accesses were excluded. Clinical indications for intervention and physical examination findings were correlated with fistulography. Need for subsequent percutaneous intervention was recorded. RESULTS: Annual nontreatment rates ranged from 3% to 14% (median, 10%). Preprocedure thrill was encountered in 45 patients in the NTG (59%) vs 6 in the CG (7.8%; P < .01). Aneurysm as indication for fistulography was more common in the NTG than the CG (19 [25%] vs 4 [5%]; P < .01). The NTG had a higher proportion of aneurysms noted on fistulography as well (38 [50%] vs 19 [25%]; P < .01). The CG had a higher proportion of patients needing subsequent percutaneous intervention vs the NTG (73 [96%] vs 38 [50%]; P < .001). CONCLUSIONS: A suggested nonintervention rate for hemodialysis access fistulography is 10%. Patients in the NTG were more likely to have a thrill on physical examination or to present with aneurysms as the clinical indicator. NTG patients were less likely to require subsequent percutaneous intervention.

Endovascular Iliocaval Stent Reconstruction for Iliocaval Thrombosis: A Multi-Institutional International Practice Pattern Survey.

BACKGROUND: Limited guidelines for the treatment and management of acute and chronic iliocaval thrombosis are published in the literature. The purpose of this report is to present global iliocaval stent reconstruction practices by interventionalists. METHODS: A 45-question survey focusing on iliocaval stent reconstruction evaluation was distributed through the Open Forum and Venous Disease Service Line of the Society of Interventional Radiology Connect website from June 20, 2017 until September 7, 2017 and the Cardiovascular and Interventional Radiological Society of Europe electronic newsletter on August 11, 2017. RESULTS: One hundred seven complete responses were received from interventional radiologists in the United States, 2 from South America, and 2 from Central America. 92.5% performed iliocaval reconstruction, and 79.8% performed the procedure for both acute and chronic iliocaval thrombosis. 82.8% completed a standardized physician assessment tool, and 91.9% obtained computed tomography (CT) venography before the procedure. 64.6% used intravascular ultrasound to guide reconstruction. 41.4% found blunt recanalization successful for >75% of patients. 63.6% used sharp recanalization for <25% of patients. 97.0% and 90.9% used uncovered and self-expanding stents, respectively. Wallstents were used most commonly. Most common stent diameters were 24-mm in the inferior vena cava, 14-mm in the common iliac vein, and 12-mm in the external iliac vein. 48.5% and 21.2% prescribed 2 and 3 anticoagulants after stent placement, respectively. 62.6% found iliocaval reconstruction provided symptomatic clinical improvement for iliocaval thrombosis in >75% of patients. 72.7% estimated their 1-year primary stent patency to be >75%. CONCLUSIONS: Iliocaval reconstruction is performed by many interventionalists; however, there are global inconsistencies in practices, suggesting a need for further research and guideline development.

A randomized comparison between an intravenous catheter system with a retractable guidewire and conventional intravenous catheters.

INTRODUCTION: The aim of this study is to compare an intravenous (IV) catheter system which uses a retractable guidewire (RG-IV) designed to facilitate IV placement with a conventional IV (C-IV) catheter control. MATERIALS AND METHODS: A prospective, randomized design was used. Patients referred to interventional radiology for outpatient procedures were offered participation. Enrollment occurred between August and November 2013. Patients were assigned to receive the RG-IV or C-IV in a 1:1 randomization scheme. After assignment, up to three attempts by a registered nurse occurred with the assigned device; if all three attempts failed, crossover to the other device occurred. The primary outcome variable was first-attempt success at IV placement. Secondary outcome variables included patient and clinician satisfaction, number of attempts, and time to successful placement. Two hundred twenty patients were enrolled (139 men, 81 women) in the study. RESULTS: Of the 220 patients, two were withdrawn prior to IV attempt leaving 218 subjects, 109 in each group. First attempt success (77% RG-IV vs. 82% C-IV, p = 0.5), number of attempts to achieve IV access (1.26 RG-IV vs. 1.29 C-IV, p = 0.98), and time to achieve IV success (2.9 minutes RG-IV vs. 2.7 C-IV, p = 0.82) did not differ between groups. Patient satisfaction with insertion was higher in the C-IV group (4.5/5 vs. 3.9/5, p<0.001) although comfort comparison was not (3.3/5 RG-IV vs. 3.5/5 C-IV, p = 0.15). CONCLUSIONS: In an interventional radiology outpatient population, the RG-IV and C-IV were comparable in first-attempt success, number of attempts, and time to achieve IV success. Patient satisfaction was higher with C-IV.

Intra-arterial Thrombolysis for Extremity Frostbite Decreases Digital Amputation Rates and Hospital Length of Stay.

PURPOSE: To report outcomes of intra-arterial thrombolysis versus non-thrombolytic management of severe frostbite with respect to digital amputation rates and hospital length of stay (LOS). MATERIALS AND METHODS: Seventeen patients with severe frostbite were identified from 2000 to 2017. Eight (47%) patients with mean age of 40 years underwent intra-arterial thrombolysis and served as the treatment group. Nine (53%) patients with mean age of 53 years received non-thrombolytic management and served as the control group. 2/8 (25%) treatment and 3/9 (33%) control patients had underlying vascular comorbidities (p = 0.25). Number of digits at risk, duration of thrombolysis, thrombolytic agents used, digits amputated, hospital LOS, and complications were recorded. RESULTS: Seven upper and nine lower extremities for a total of 80 digits were at risk in the treatment cohort. Eight upper and 12 lower extremities for a total of 100 digits were at risk in the control group. Mean duration of thrombolysis was 26 h. All treatment patients received tissue plasminogen activator in addition to systemic heparin. 4/16 (25%) limbs received intra-arterial alprostadil, 2/16 (13%) received nitroglycerin, and 2/16 (13%) received nicardipine. 12/80 (15%) treatment digits and 77/100 (77%) control digits required amputation (p = 0.003). Average hospital LOS was 14 days in the treatment group and 38 days in the control group (p = 0.011). No major complications occurred in the treatment group; however, 2/9 (22%) patients in the control group required extended hospitalizations secondary to amputation complications. CONCLUSIONS: Intra-arterial thrombolysis reduces digital amputation rates and hospital LOS in the setting of severe frostbite.

Three-Dimensional Printing Facilitates Successful Endovascular Closure of a Type II Abernethy Malformation Using an Amplatzer Atrial Septal Occluder Device.

Type II Abernethy malformations, characterized by side-to-side portosystemic shunting with preserved intrahepatic portal venous system, have been treated with shunt closure surgically and endovascularly. Three-dimensional printing has been used to develop highly accurate patient-specific representations for surgical and endovascular planning and intervention. This innovation describes 3-dimensional printing to successfully close a flush-oriented type II Abernethy malformation with discrepant dimensions on computed tomography, conventional venography, and intravascular ultrasound, using a 12-mm Amplatzer atrial septal occluder device.

Concurrent Central Venous Stent and Central Venous Access Device Placement Does Not Compromise Stent Patency or Catheter Function in Patients with Malignant Central Venous Obstruction.

PURPOSE: To determine if concurrent placement of a central venous stent (CVS) and central venous access device (CVAD) compromises stent patency or catheter function in patients with malignant central venous obstruction. MATERIALS AND METHODS: CVS placement for symptomatic stenosis resulting from malignant compression was performed in 33 consecutive patients who were identified retrospectively over a 10-year period; 28 (85%) patients had superior vena cava syndrome, and 5 (15%) had arm swelling. Of patients, 11 (33%) underwent concurrent CVS and CVAD placement, exchange, or repositioning; 22 (67%) underwent CVS deployment alone and served as the control group. Types of CVADs ranged from 5-F to 9.5-F catheters. Endpoints were CVS patency as determined by clinical symptoms or CT and CVAD function, which was determined by clinical performance. RESULTS: All procedures were technically successful. There was no difference between the 2 groups in clinically symptomatic CVS occlusion (P = .2) or asymptomatic in-stent stenosis detected on CT (P = .5). None of the patients in the CVS and CVAD group had recurrent clinical symptoms, but 3 (30%) of 10 patients with imaging follow-up had asymptomatic in-stent stenosis. In the control group, 3 (14%) patients had clinically symptomatic CVS occlusion and required stent revision, whereas 4 (21%) of 19 patients with imaging follow-up had asymptomatic in-stent stenosis. During the study, 2 (20%) functional but radiographically malpositioned catheters were identified (0.66 per 1,000 catheter days). CONCLUSIONS: Presence of a CVAD through a CVS may not compromise stent patency or catheter function compared with CVS placement alone.

A Survey of Pulmonary Arteriovenous Malformation Screening, Management, and Follow-Up in Hereditary Hemorrhagic Telangiectasia Centers of Excellence.

PURPOSE: To determine current practice regarding screening, management, and follow-up of pulmonary arteriovenous malformations (PAVMs), particularly those with feeding arteries <3 mm in diameter, in those patients with hereditary hemorrhagic telangiectasia (HHT) at HHT Centers of Excellence. MATERIALS AND METHODS: A 32-question survey focusing on PAVM screening, management, and follow-up was sent to 147 participants at HHT Centers worldwide. RESULTS: Thirty-three responses were received (22%); 60% from interventional radiologists and 20% from pulmonologists; 67% from the USA, 21% European, and 6% Asian. In HHT patients with initial negative screening echocardiogram, 60% recommended repeat screening contrast echocardiogram in 5 years, while 15% felt that no additional screening was necessary in these patients. Fifty-nine percentage reported never having seen a patient with initial negative contrast echocardiogram become positive. In patients with grade 1 echocardiograms, 41% recommended contrast-enhanced CT as the next step in management, 22% recommended non-contrast CT, and 22 and 3% recommended repeat echocardiogram in 5 and 10 years, respectively. In patients with grade 1 echocardiograms but no visible PAVMs, opinions regarding the use of bubble filters were evenly divided, while 79% recommended prophylactic antibiotics prior to invasive procedures. Eighty percentages of respondents treat PAVMs with feeding artery less than 3 mm, and 52% treat feeders less than 2 mm. Regarding follow-up, 71% reported seeing PAVM recurrence at the site of a previously completely treated PAVM. CONCLUSION: There is inconsistency in practice regarding PAVM screening, management, and follow-up, suggesting a need for further research and guideline development.

Institution of a Hospital-Based Central Venous Access Policy for Peripheral Vein Preservation in Patients with Chronic Kidney Disease: A 12-Year Experience.

PURPOSE: To describe the implementation of nursing-based venous access team (VAT) and standardized interventional radiology (IR) protocols in accordance with Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines to provide central venous access while preserving peripheral veins in patients with chronic kidney disease (CKD). MATERIALS AND METHODS: Review of peripherally inserted central catheter (PICC) and small-bore central catheter (SBCC) referral and placement data from VAT and IR databases was conducted over a 12-year period. SBCC referral was automatic for patients with creatinine levels ≥ 3 mg/dL or a renal transplant regardless of creatinine level unless dialysis was not planned. All SBCC insertions, regardless of referral source, were identified and reviewed, and SBCC placements prompted by K/DOQI PICC contraindication were identified. Catheter types, indications, access sites, technical success, and complications were ascertained. RESULTS: A total of 35,781 requests for PICC placement were made to the VAT; 1,889 (5%) were referred to IR for SBCC placement per institutional policy, and 2,200 SBCCs were attempted or newly placed during this period, 1,879 (85%) based on K/DOQI contraindications. Primary indication for SBCC placement was antibiotic therapy (59%). Access sites included right internal jugular vein (IJV) (70%), left IJV (24%), right external jugular vein (EJV) (3%), left EJV (2%), right common femoral vein (CFV) (0.3%), and left CFV (0.2%). Technical success rate of SBCC insertion was 99%. Six minor (0.3%) and three major (0.1%) complications occurred. CONCLUSIONS: Automatic referral for SBCC placement in patients with CKD via VAT and IR protocols may eliminate PICC placement and thereby protect peripheral veins needed for hemodialysis. SBCC placement has high technical success and low complication rates.

Significance of Echocardiographically Detected Central Venous Catheter Tip-Associated Thrombi.

PURPOSE: To explore significance, management, and outcomes of central venous catheter (CVC) tip-associated thrombi incidentally detected on echocardiography. MATERIALS AND METHODS: Echocardiogram data from all patients with CVCs from October 2009 to June 2011 were reviewed (N = 170). Patients with CVC tip-associated thrombi were selected (n = 49). Echocardiograms were reviewed for ejection fraction, presence of patent foramen ovale (PFO), presence of other intracardiac shunts, and mean thrombus size. Management decisions, thrombus extension, pulmonary embolism, paradoxical emboli, and stroke within 3 months were recorded. RESULTS: Mean thrombus size was 2.1 cm (range, 0.5-5.7 cm). Of patients with thrombi, 11 (22%) were already on anticoagulation, and there was no change in management. Anticoagulation was started without complications in 17 (35%) patients, the catheter was removed in 4 (8%) patients, and no new treatment was initiated in 17 (35%) patients. Of these 17 patients, 16 (94%) developed no complications. One (6%) patient with a PFO and right-to-left shunt experienced a stroke before PFO closure. After surgical closure of the PFO, the same patient developed catheter tip-associated thrombus without complication. There were no pulmonary emboli, strokes, or other detected embolic phenomena. CONCLUSIONS: In this sample with CVC tip-associated thrombi but without PFO or other intracardiac shunts, no embolic or other complications were detected, regardless of anticoagulation status. These data suggest a benign course for such thrombi and that anticoagulation, catheter removal, thrombectomy, and thrombolysis may be unnecessary when catheter tip-associated thrombi are incidentally detected on echocardiography.

Approach to the Swollen Arm With Chronic Dialysis Access: It's Not Just Deep Vein Thrombosis.

The purposes of this pictorial essay are as follows: (1) Review a systematic approach to using sonography in the initial evaluation of patients with acute arm swelling and permanent dialysis access. (2) Identify normal grayscale and Doppler findings in arteriovenous fistulas and grafts. (3) Discuss a spectrum of vascular differential diagnoses for arm swelling in this setting, including stenosis of the access, draining vein complications, thrombosis, steal syndrome, and aneurysms, as well as several nonvascular causes. (4) Recognize findings that warrant further imaging evaluation or intervention.

Splenic Artery Syndrome after orthotopic liver transplantation: a review.

Splenic Artery Syndrome (SAS) has emerged as a controversial cause for graft ischemia in orthotopic liver transplant (OLTx) recipients. A complex combination of factors including hepatic artery hypoperfusion and portal hyperperfusion can result in SAS. Clinical and laboratory findings suggest graft ischemia but are generally non-specific. Conventional angiography findings of hepatic artery hypoperfusion with early and rapid filling of the splenic artery are suggestive of the diagnosis in the appropriate clinical setting. Treatment involves proximal splenic artery embolization, surgical splenic artery ligation, or in extreme cases, splenectomy. Most patients with SAS improve clinically following treatment. However, no randomized control trials are available to compare treatment options. Identification of at risk patients with pre-operative CT scans and intra-operative ultrasound has been proposed by some and may allow for prophylactic treatment of SAS.