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.

Supply Costs in Complex and Routine Inferior Vena Cava Filter Retrieval: 10 Years' Data from a Single Center.

PURPOSE: To characterize the medical supply costs associated with inferior vena cava filter retrieval (IVCFR) using endobronchial forceps (EFs), a snare, or Recovery Cone (RC). MATERIALS AND METHODS: In total, 594 of 845 IVCFRs attempted at a tertiary referral hospital between October 1, 2012, and June 20, 2022 were categorized by intended retrieval strategy informed by, rotational cavography as follows: (a) EF (n = 312) for tilted or tip-embedded/strut-embedded filters and for long-dwelling closed-cell filters and (b) a snare (n = 255) or (c) RC (n = 27) for other well-positioned filters with or mostly without hooks, respectively. List prices of relevant supplies at time of retrieval were obtained or, rarely, estimated using a standard procedure. Contrast use, fluoroscopic time, filter type, dwell time, and patient age and sex were recorded. Mean between-group cost differences were estimated by linear regression, adjusting for date. Additional models evaluated filter type, dwell time, and patient-level effects. RESULTS: Of the 594 IVCFRs, 591 were successful, whereas 2 EF and 1 snare retrievals failed. Moreover, 4 EF retrievals were successful with a snare and 2 with smaller EF, 12 snare retrievals were successful with EF, 1 RC retrieval was successful with a snare and 2 with EF. Principal model indicated a significantly lower mean cost of EF ($564.70, SE ± 9.75) than that of snare ($811.29, SE ± 10.83; P < .0001) and RC ($1,465.48, SE ± 47.12; P < .0001) retrievals. Adjusted models yielded consistent results. Had all retrievals been attempted with EF, estimated undiscounted full-period supplies savings would be $87,201.51. CONCLUSIONS: EFs are affordable for complex IVCFR, and extending their use to routine IVCFR could lead to considerable cost savings.

Quality Improvement Report: Design and Implementation of a Radiology E-Consult Service.

Electronic consultations (e-consults) mediated through an electronic health record system or web-based platform allow synchronous or asynchronous physician-to-physician communication. E-consults have been explored in various clinical specialties, but relatively few instances in the literature describe e-consults to connect health care providers directly with radiologists.The authors outline how a radiology department can implement an e-consult service and review the development of such a service in a large academic health system. They describe the logistics, workflow, turnaround time expectations, stakeholder management, and pilot implementation and highlight challenges and lessons learned.

A Practical Guide for Left Adrenal Vein Sampling in Patients with Left Renal Vein Variants.

BACKGROUND: The presence of left renal vein (LRV) variants can increase the complexity of adrenal vein sampling (AVS), an already technically demanding procedure. While AVS literature often focuses on the right adrenal vein, an understanding of common LRV variants, their relationship with the left adrenal vein, and principles for successful catheterization can facilitate AVS. This guide provides practical, technical tips for AVS for duplicated (Du), circumaortic (Ca), and retroaortic (Ra) LRVs. METHODS: AVS cases were identified at a single institution (June 2009-March 2023) based on adrenophrenic trunk drainage relative to variant LRVs. Available cross-sectional imaging was reviewed to evaluate LRV anatomy pre-procedure. Twenty-seven cases (1 DuLRV, 13 CaLRVs, and 13 RaLRVs) were identified. Diagnostic AVS was confirmed by a threshold selectivity index. Literature on LRV anatomic variants was also reviewed. RESULTS: Based on the authors' experience and literature review, the following principles can guide AVS in the setting of LRV variants. In the presence of DuLRV or CaLRV, the left adrenal vein invariably drains into a normally positioned, pre-aortic LRV limb, so AVS can proceed as expected with a Simmons as the catheter of choice. In contrast, a LAV draining into a RaLRV may require a hockey stick-like catheter, or in rare cases a microcatheter, for selecting and sampling, due to the longer RaLRV course, which usually drains into the IVC more inferiorly and can be stenotic where the aorta crosses. CONCLUSION: Knowing the presence and understanding the anatomy of LRV variants can facilitate an efficient AVS.

Outcomes following Exchange and Upsizing of Malfunctioning Small-Caliber Double-J Ureteral Stents.

PURPOSE: To determine the effectiveness of exchange and upsizing of malfunctioning small-caliber double-J (JJ) ureteral stents. MATERIALS AND METHODS: Thirty-one patients with malfunctioning cystoscopically placed small-caliber (6 or 7 F) JJ stents underwent transurethral (n = 28) or transrenal (n = 3) exchange and upsizing to a large-caliber (10 F) JJ stent from 2013 to 2022. Ureteral obstruction was malignant in 20 patients (65%) and benign in 11 (35%). Fifteen patients (48%) presented with persistent hydroureteronephrosis and 16 patients (52%) with worsening hydronephrosis. Acute kidney injury (AKI) was present in 19 patients (61%) at the time of stent malfunction. Therapeutic success was defined as resolution of hydronephrosis and AKI, if present. RESULTS: JJ stent exchange and upsizing was technically successful in 31 patients (100%) with no immediate adverse events. Therapeutic success was achieved in 27 patients (87%). During follow-up (median, 97 days; IQR, 32-205 days), 2 patients who initially achieved therapeutic success had stent malfunction, requiring conversion to percutaneous nephrostomy drainage (2/27, 7%). CONCLUSIONS: Exchange and upsizing to large-caliber JJ stents can relieve urinary obstruction and resolve AKI in patients with malfunctioning small-caliber JJ stents. Large-caliber JJ stents should be considered as a salvage option for patients who wish to continue internal drainage and avoid percutaneous nephrostomy.

Comparison of Transthoracic Contrast Echocardiography with High-Resolution Chest CT after Embolization of Pulmonary Arteriovenous Malformation.

PURPOSE: To compare postembolotherapy follow-up graded transthoracic contrast echocardiography (TTCE) and high-resolution computed tomography (CT) of the chest and to evaluate the use of graded TTCE in the early postembolic period. MATERIALS AND METHODS: Thirty-five patients (6 men and 29 women; mean age, 56 years; range, 27-78 years) presenting for postembolotherapy follow-up between 2017 and 2021 with concurrent high-resolution CT and graded TTCE were analyzed retrospectively. Untreated pulmonary arteriovenous malformations (PAVMs) with a feeding artery of ≥2 mm were considered treatable. RESULTS: Ninety-four percent of patients (33 of 35) did not have treatable PAVMs on high-resolution CT. TTCE was negative for shunts (Grade 0) in 34% of patients (n = 12). Of patients with a TTCE positive for shunts (23 of 35, 66%), 83% had a Grade 1 shunt, 13% had a Grade 2 shunt, and 4% had a Grade 3 shunt. No patient with a Grade 0 or 1 shunt had a treatable PAVM on high-resolution CT. Of the 2 patients with PAVMs requiring treatment, one had a Grade 2 shunt and one had a Grade 3 shunt. TTCE grade was significantly associated with the presence of a treatable PAVM on high-resolution CT (P < .01). CONCLUSIONS: Graded TTCE predicts the need for repeat embolotherapy and does so reliably in the early postembolotherapy period. This suggests that graded TTCE can be utilized in the postembolotherapy period for surveillance, which has the potential to lead to a decrease in cumulative radiation in this patient population.

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.

Comparison of Fibered versus Nonfibered Coils for Venous Embolization in an Ovine Model.

PURPOSE: To compare nylon fibered (F) with nonfibered (NF) coils for embolization in an ovine venous model. MATERIALS AND METHODS: Four- to 8-mm-diameter, 0.035-inch F and NF coils were deployed in 24 veins in 6 sheep. The number of coils, total length of the coils, and length of implanted coil pack required to achieve complete stasis were recorded, as were vessel diameter, radiation dose, ease of packing, damage to embolized vessel, and time to stasis. Venography at 1 and 3 months was used to assess the migration and durability of vessel occlusion. Veins were harvested at 3 months. RESULTS: F and NF coils were deployed in 24 veins, and stasis was achieved, without immediate coil migration or vessel damage. The mean numbers of F and NF coils per vein were 5 and 8.75, respectively (P = .007). The vessel diameter between the groups was not statistically different. The total coil length (F, 70 cm vs NF, 122.5 cm; P = .0007), coil pack length (F, 29.3 mm vs NF, 39.4 mm; P = .003), time to stasis (F, 5.3 minutes vs NF, 9.0 minutes; P = .008), and radiation dose (F, 25.3 mGy vs NF, 34.9 mGy; P = .037) were significantly different between the groups. Challenges with the animal model prevented conclusive long-term results. Migration occurred with 8 of 11 (72%) coil packs in the femoral veins and 0 of 13 (0%) coil packs in the internal iliac and deep femoral veins. Venography demonstrated that of 16 remaining coil packs, 11 were occluded at 1 month and 10 remained occluded at 3 months. CONCLUSIONS: Fibers allow for significantly fewer coils to achieve immediate venous occlusion.

Tricks of the trade: Techniques for preoperative localization in reoperative parathyroidectomy.

BACKGROUND: Reoperative parathyroidectomy for recurrent/persistent primary hyperparathyroidism (PHPT) has high rates of failure. The goal of this study was to analyze our experience with imaging and parathyroid vein sampling (PAVS) for recurrent/persistent PHPT. METHODS: We performed a retrospective cohort study (2002-2018) of patients with recurrent/persistent PHPT undergoing reoperative parathyroidectomy. RESULTS: Among 181 patients, the most common imaging study was sestamibi (89.5%), followed by ultrasound (75.7%). CT had the highest rate of localization (70.8%) compared to sestamibi (58.0%) and ultrasound (47.4%). PAVS was performed in 25 patients, and localized in 96%. Ultrasound and sestamibi both demonstrated 62% PPV for operative pathology, compared to 41% in CT. PAVS was 95% sensitive with 95% PPV for predicting the correct side of abnormal parathyroid tissue. CONCLUSIONS: We recommend a sequential imaging evaluation for reoperative parathyroidectomy, with sestamibi and/or ultrasound followed by CT. PAVS should be considered if non-invasive imaging fails to localize.

Choosing the right treatment for the right lesion, part I: a narrative review of the role of plain balloon angioplasty in dialysis access maintenance.

Background and Objective: The majority of patients with end-stage renal disease (ESRD) requiring hemodialysis (HD) do so via an arteriovenous fistula (AVF) or graft. Both of these accesses are complicated by dysfunction related to neointimal hyperplasia (NIH) and subsequent stenosis. Percutaneous balloon angioplasty using plain balloons is the first line treatment for clinically-significant stenosis, with excellent initial response rates, however, with poor long-term patency and need for frequent reintervention. Recent research has sought to improve patency rates utilizing antiproliferative drug-coated balloons (DCBs), however, their role in treatment has not yet been fully determined. In part one of this two-part review, we aim to provide a comprehensive overview of the mechanisms of arteriovenous (AV) access stenosis, the evidence behind their treatment with high-quality plain balloon angioplasty techniques, and treatment considerations for specific stenotic lesions. Methods: An electronic search was performed on PubMed and EMBASE to identify relevant articles from 1980 to 2022. The highest available level of evidence regarding stenosis pathophysiology, angioplasty techniques, and approaches to treating different types of lesions within fistulas and grafts were included as part of this narrative review. Key Content and Findings: NIH, and subsequent stenoses, develop via a combination of upstream events, causing vascular damage, and downstream events, representing the subsequent biologic response. The large majority of stenotic lesions can be treated utilizing high-pressure balloon angioplasty, with the addition of ultra-high pressure balloon (UHPB) angioplasty for resistant lesions and prolonged angioplasty with progressive balloon upsizing for elastic lesions. Additional treatment considerations must be taken into account when treating specific lesions, including cephalic arch and swing point stenoses in fistulas and graft-vein anastomotic stenoses in grafts, amongst others. Conclusions: High-quality plain balloon angioplasty, performed utilizing the available evidence-basis regarding technique and considerations for specific lesion locations, is successful in treating the large majority of AV access stenoses. While initially successful, patency rates remain non-durable. Part two of this review will discuss the evolving role of DCBs, which seek to improve angioplasty outcomes.

Choosing the right treatment for the right lesion, Part II: a narrative review of drug-coated balloon angioplasty and its evolving role in dialysis access maintenance.

Background and Objective: Drug-coated balloons (DCBs) seek to inhibit restenosis in treated hemodialysis access lesions by delivering an anti-proliferative agent (paclitaxel) into the vessel wall. While DCBs have proven effective in the coronary and peripheral arterial vasculature, the evidence for their use in arteriovenous (AV) access has been less robust. In part two of this review, a comprehensive overview of DCB mechanisms, implementation, and design is provided, followed by an examination of the evidence basis for their use in AV access stenosis. Methods: An electronic search was performed on PubMed and EMBASE to identify relevant randomized controlled trials (RCTs) comparing DCBs and plain balloon angioplasty from January 1, 2010 to June 30, 2022 published in English. As part of this narrative review, a review of DCB mechanisms of action, implementation, and design is provided, followed by a review of available RCTs and other studies. Key Content and Findings: Numerous DCBs have been developed, each with unique properties, although the degree to which these differences impact clinical outcomes is unclear. Target lesion preparation, achieved by pre-dilation, and balloon inflation time have proven important factors in achieving optimal DCB treatment. Numerous RCTs have been performed, but have suffered from significant heterogeneity, and have often reported contrasting clinical results, making it difficult to draw conclusions on how to implement DCBs in daily practice. On the whole, it is likely there is a population of patients who benefit from DCB use, but it is unclear which patients benefit most and what device, technical, and procedural factors lead to optimal outcomes. Importantly, DCBs use appears safe in the end-stage renal disease (ESRD) population. Conclusions: DCB implementation has been tempered by the lack of clear signal regarding the benefits of DCB use. As further evidence is obtained, it is possible that a precision-based approach to DCBs may shed light onto which patients will truly benefit from DCBs. Until that time, the evidence reviewed herein may serve to guide interventionalists in their decision making, knowing that DCBs appear safe when used in AV access and may provide some benefit in certain patients.

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.

Adrenal Vein Sampling Results and Surgical Outcomes in Patients with a Normal Plasma Aldosterone Concentration.

PURPOSE: To determine the utility of adrenal vein sampling (AVS) and outcomes after adrenalectomy in patients with normal plasma aldosterone concentration (PAC) and elevated aldosterone-to-renin ratio (ARR). MATERIALS AND METHODS: The study sample included 106 patients with ARR greater than 20 and PAC between 5 and 15 ng/dL (normal PAC group) who underwent AVS from 2005 to 2021. These patients were compared with a cohort of 106 patients with ARR >20 and PAC >15 ng/dL (high PAC group) who underwent AVS during the same period. Data regarding baseline clinical characteristics, lateralization indices from AVS, and outcomes after adrenalectomy were analyzed. RESULTS: AVS was technically successful in 210 patients (210/212, 99%). A smaller proportion of patients in the normal PAC group showed a lateralization index of >4 compared with those in the high PAC group (44% vs 64%, P <.01). A similar proportion of patients in the normal PAC group experienced improved or cured hypertension after adrenalectomy compared with that in the high PAC group (94% vs 88%, P =.31). Hypokalemia was cured in all patients in the normal PAC group after adrenalectomy compared with 98% of patients in the high PAC group (100% vs 98%, P = 1). CONCLUSIONS: Although lateralization is less frequent for patients with normal PAC, patients who do lateralize show similar blood pressure response and correction of hypokalemia after adrenalectomy, regardless of initial plasma aldosterone levels. Therefore, patients with PAC <15 ng/dL should still be considered for AVS provided the ARR is elevated.

Endobronchial Forceps Retrieval of Embedded Inferior Vena Cava Filters: Retrieval of 535 Filters at a Single Center.

PURPOSE: To report results of 16 years of using the endobronchial forceps technique to remove embedded inferior vena cava (IVC) filters. MATERIALS AND METHODS: Between January 2005 and June 2021, 534 patients (310 women and 224 men) with a mean age of 52 years (standard deviation [SD] ± 16 years) presented for complex filter retrieval of 535 tip- or strut-embedded IVC filters. Tip-embedded filters were diagnosed on rotational venography. Filters were considered strut-embedded if they were closed-cell filters with dwell times of >6 months. The filter was dissected from the IVC using rigid bronchoscopy forceps and removed through a vascular sheath. RESULTS: The endobronchial forceps technique was successful in 530 of 537 retrieval attempts on an intention-to-treat basis (98.7%); a total of 530 filters were retrieved. There were 7 failures: (a) 5 failed retrieval attempts (2 that were retrieved successfully in subsequent procedures) and (b) 2 for which retrieval was not attempted. The mean filter dwell time was 1,459 days (SD ± 1,617 days). Laser sheaths were not used for any removal. Filters included herein were 137 Celect (94 Celect and 43 Celect Platinum), 99 Günther Tulip, 72 Option (48 Option and 24 Option Elite), 68 G2, 45 G2X/Eclipse, 42 Denali, 30 OptEase, 29 Recovery, 7 Meridian, and 6 ALN with Hook filters. Thirty-four minor (6.3%) and 11 major (2%) adverse events (AEs) occurred, which did not result in permanent sequelae. CONCLUSIONS: Use of endobronchial forceps for removal of tip- and strut-embedded retrievable IVC filters is effective and has low AE rates.

Grasp-and-Fold Technique for Complex Inferior Vena Cava Filter Retrieval.

This study evaluated the use of the grasp-and-fold technique for complex forceps retrieval of inferior vena cava (IVC) filters. A retrospective study of 14 patients (12 women and 2 men) who had either deeply tip-embedded or severely distorted IVC filters was performed at a single institution over 10 years. In this technique, endobronchial forceps were used to fold the filter in half to remove it through the sheath because the filter tip could not be accessed by dissection. The grasp-and-fold technique successfully removed all 14 filters. One patient had retained filter struts, which were present before the procedure. One mild and 5 moderate adverse events (AEs), including fracture fragment embolization requiring retrieval and self-limited IVC extravasation, occurred. No severe AEs occurred. In this small patient cohort, the grasp-and-fold forceps technique successfully retrieved deeply tip-embedded or distorted IVC filters with inaccessible tips.

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.

Local Anesthesia in Interventional Radiology.

Interventional radiology is an evolving field that treats a variety of diseases. Local anesthetics is an important component of pain management during interventional radiologic procedures. It is highly effective and generally safe for routine procedures. However, local anesthetics can be associated with painful initial injection, allergic reactions, and rare but potentially devastating systemic toxicities. Recent evidence has shown that buffered solution and warm local anesthetics may reduce injection discomfort and improve clinical efficacy. Sensible safety practices and prompt recognition/treatment of the systemic toxicity are of paramount importance to provide safe local anesthesia. Interventional radiologists should be familiar with the basic pharmacology, common local anesthetics, optimizing strategies, complications, and management to provide safe and effective local anesthesia for patients.