An Introductory Guide to Artificial Intelligence in Interventional Radiology: Part 1 Foundational Knowledge.

Artificial intelligence (AI) is rapidly evolving and has transformative potential for interventional radiology (IR) clinical practice. However, formal training in AI may be limited for many clinicians and therefore presents a challenge for initial implementation and trust in AI. An understanding of the foundational concepts in AI may help familiarize the interventional radiologist with the field of AI, thus facilitating understanding and participation in the development and deployment of AI. A pragmatic classification system of AI based on the complexity of the model may guide clinicians in the assessment of AI. Finally, the current state of AI in IR and the patterns of implementation are explored (pre-procedural, intra-procedural, and post-procedural).

An Introductory Guide to Artificial Intelligence in Interventional Radiology: Part 2: Implementation Considerations and Harms.

The introduction of artificial intelligence (AI) in interventional radiology (IR) will bring about new challenges and opportunities for patients and clinicians. AI may comprise software as a medical device or AI-integrated hardware and will require a rigorous evaluation that should be guided based on the level of risk of the implementation. A hierarchy of risk of harm and possible harms are described herein. A checklist to guide deployment of an AI in a clinical IR environment is provided. As AI continues to evolve, regulation and evaluation of the AI medical devices will need to continue to evolve to keep pace and ensure patient safety.

Insights From the FDA's MAUDE Database Regarding the Real-World Safety of Jetstream Atherectomy for Peripheral Arterial Disease.

INTRODUCTION: Rotational atherectomy has shown promise as an adjunctive therapy to percutaneous transluminal angioplasty (PTA) and stenting for the treatment of peripheral arterial disease (PAD). However, published data regarding the safety of these devices are limited. The Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database collects reports of adverse event for medical devices. We present 3 years of MAUDE adverse events data for the Jetstream Atherectomy System (Boston Scientific) for the treatment of PAD. MATERIALS AND METHODS: We searched MAUDE from January 1, 2019 to December 31, 2021. Duplicate reports and those with insufficient information were excluded, leaving a total of 500 reports for analysis. Adverse events were categorized as either patient complication, device malfunction, or both. Adverse events were classified using the Cardiovascular and Interventional Radiological Society of Europe's (CIRSE) classification system for adverse events. RESULTS: The most common patient complications were embolism (22; 4.4%), dissection (17; 3.4%), vessel perforation (12; 2.4%), and device fracture in the patient (6; 1.2%). The most common modes of device failure were entrapment of the device on the guidewire (134; 27%), loss of blade rotation (116; 23%), loss of aspiration (99; 20%), and mechanical damage (57; 11%). As per the CIRSE adverse events classification, most events had no post-procedural sequelae (475; 95%), followed by those requiring prolonged observation (14; 2.8%), and post-procedural therapy without long-term sequelae (10; 2.0%). One hundred six devices (21%) were returned for manufacturer analysis. CONCLUSION: We highlight important adverse events encountered in real-world practice with the Jetstream Atherectomy System. This analysis provides further understanding of the safety profile and modes of failure of Jetstream, and could help guide improvements in product design and manufacturer-user training. There is greater need for root-cause analysis that can aided by returning devices to the manufacturer. CLINICAL IMPACT: We highlight important adverse events encountered in real-world practice with the Jetstream Atherectomy System. The MAUDE database is useful for capturing and characterizing modes of device failure/malfunction not typically described in conventional clinical studies. This may provide valuable information to help guide improvements in product design and manufacturer-user training. This information could also potentially be useful in helping establish manufacturer and product liability in the setting of medicolegal claims. We hope that by contributing to the growing understanding of the safety profile of the Jetstream Atherectomy System, our study may help physicians and patients come to more informed decisions regarding treatment options for PAD.

Real-World Experience With the Angio-Seal Closure Device: Insights From Manufacturer and User Facility Device Experience Database.

PURPOSE: Angio-Seal (Terumo Medical Corporations, Somerset, New Jersey) device is indicated for femoral arteriotomy closure. Real-world published data on complications are limited. We present 1 year of safety events involving Angio-Seal from the US Food and Drug Administration's post-market surveillance database of Manufacturer and User Facility Device Experience (MAUDE). Steps for managing frequent device-related problems are discussed. MATERIALS AND METHODS: Angio-Seal MAUDE data from November 2019 to December 2020 was classified according to (1) mode of device failure, (2) complication, (3) treatment, and (4) Cardiovascular and Interventional Radiological Society of Europe (CIRSE) adverse event classification system. RESULTS: There were 715 safety events, involving Angio-Seal VIP (93.1%), Evolution (5.7%), STS Plus (1.1%), and sizes 6F (62.5%) and 8F (37.5%). Failure mode involved unrecognized use of a damaged device (43.4%), failed deployment (20.1%), failed arterial advancement (6.3%), detachment of device component (4.9%), failed retraction (3.6%), operator error (1.1%), and indeterminate (20.6%). Of total, 44.8% of events were associated with patient harm. Complications involved minor blood loss (34.1%), hematoma (5.6%), significant blood loss (1.4%), and pseudoaneurysm (1.4%). Of total, 43.3% of cases required manual compression (MC), whereas 8.8% required more advanced intervention. Interventions included surgical repair (49.2%), thrombin injection (9.5%), balloon tamponade (6.3%), covered stent (4.8%), and unspecified (30.2%). Majority of safety events were CIRSE grade 1 (92.0%), followed by grades 2 (3.1%), 3 (4.6%), and 6 (deaths, 0.3%). Minority of devices were returned for manufacturer analysis (27.8%). CONCLUSIONS: The majority of safety events were associated with minor blood loss or local hematoma and could be addressed with MC alone. Most events were attributed to damaged device; however, very few devices were returned to manufacturer for analysis. This should be encouraged to allow for root cause analysis in order to improve safety profile of devices. System-level strategies for addressing barriers to under-reporting of safety events may also be considered. CLINICAL IMPACT: Our study highlights important safety events encountered in real-world practice with Angio-Seal closure device. The MAUDE database captures real-world device malfunctions not typically appreciated in conventional clinical trials. Our study provides valuable insight for clinician-users on anticipating and managing the most common device malfunctions. Additionally, our data provide feedback for manufactures to optimize product design and direct manufacturer user training to improve safety. Finally, we hope that the study promotes system-level strategies that foster reporting of safety events and undertaking of root cause analysis.

The Use of Vascular Closure Devices for Brachial Artery Access: A Systematic Review and Meta-Analysis.

PURPOSE: To estimate the rates of technical success and adverse events of vascular closure devices (VCDs) in the brachial artery and compare the rates of adverse events with manual compression. MATERIALS AND METHODS: MEDLINE and Embase were searched for observational studies examining VCDs in the brachial artery. Meta-analyses were performed using random effects for the following outcomes: (a) technical success, (b) hematoma at the access site, (c) pseudoaneurysm, (d) local neurological adverse events, and (e) total number of adverse events. A pairwise meta-analysis compared VCD with manual compression for the outcomes of hematoma and the total number of adverse events. RESULTS: Of 1,761 eligible records, 16 studies including 510 access sites were included. Primary procedures performed were peripheral arterial disease interventions, percutaneous coronary intervention, and endovascular thrombectomy for ischemic stroke. The technical success rate was 93% (95% CI, 87%-96%; I2 = 47%). Data on the following adverse events were obtained via meta-analysis: (a) hematoma, 9% (5%-15%; I2 = 54%); (b) stenosis or occlusion at access site, 3% (1%-14%; I2 = 51%); (c) infection, 0% (0%-5%; I2 = 0%); (d) pseudoaneurysm, 4% (1%-13%; I2 = 61%); (e) local neurological adverse events, 5% (2%-13%; I2 = 54%); and (f) total number of adverse events, 15% (10%-22%; I2 = 51%). Angio-Seal success rate was 96% (93%-98%; I2 = 0%), whereas the ExoSeal success rate was 93% (69%-99%; I2 = 61%). When comparing VCD and manual compression, there was no difference in hematoma formation (relative risk, 0.75; 95% CI, 0.35-1.63; I2 = 0%; P = .47) or the total number of adverse events (relative risk, 0.75; 95% CI, 0.35-1.58; I2 = 76%; P = .45). CONCLUSIONS: Despite being off-label, studies suggest that VCDs in the brachial artery have a high technical success rate. There was no significant difference in adverse events between VCDs and manual compression in the brachial artery.

Vascular surgical management of profunda femoris artery aneurysms: A single center experience.

OBJECTIVE: Profunda femoris artery aneurysms (PFAAs), which comprise true profunda femoris artery aneurysms (TPFAAs) and profunda femoris artery pseudoaneuryms (PFA PSAs), are rare but clinically significant diseases of the peripheral arterial vasculature. Our aim is to describe our institution's 15-year experience with PFAAs (TPFAAs and PFA PSAs) to provide insight into patient characteristics, diagnostic imaging modalities, and surgical interventions that contribute to clinically important outcomes in patients with PFAAs. METHODS: We conducted a retrospective study at our institution using our radiology database. RESULTS: We identified six patients with PFA PSAs and four patients with TPFAAs. The clinical presentation of PFA PSAs included a triad of thigh pain, bleeding, and unexplained anemia. There was variety in the aetiologies of PFA PSAs, arising from catheterizations, upper thigh fractures, anastomotic complications, or unknown causes. Most patients with PFA PSAs had hypertension and coronary artery disease, and half of our cohort had peripheral vascular disease. All patients were imaged with duplex ultrasonography (DUS) or computed tomography (CT), the latter being more accurate. All patients with PFA PSAs underwent endovascular treatment, including glue, thrombin, or coil embolization as well as stent-graft insertions. All TPFAAs presented to our center were small and incidentally discovered, explaining the conservative management of our TPFAAs. Two of the four TPFAAs were idiopathic in nature, while one was attributed to post-stenotic dilatation, and another was found in a patient with Ehlers Danlos Syndrome. There was an association between TPFAAs and multiple synchronous or asynchronous aneurysms. CONCLUSION: Pseudoaneurysms of the PFA are mostly iatrogenic in nature and can present with the triad of thigh swelling, bleeding, and unexplained anemia. If the clinical picture is suggestive of a PFA PSA but DUS does not detect a pseudoaneurysm, CT may be added as a more accurate imaging modality. Endovascular embolization is used in smaller pseudoaneurysms and in poor surgical candidates. Multiple glue, coil, or thrombin injections may be required to fully thrombose the pseudoaneurysm sac. True aneurysms of the PFA are associated with synchronous/asynchronous aneurysms and small TPFAAs should be carefully monitored, as there is a risk of enlargement and rupture.

Utility of 4D CT in endoleak characterization after advanced endovascular aortic repair.

OBJECTIVES: To assess the performance of dynamic or 4D CT in characterizing endoleaks in advanced endovascular aortic repair (branched and fenestrated) when other modalities fail to fully characterize the leak, most often conventional CTA. METHODS: Retrospective review of 13 patients from 2008 to 2021 who underwent 16 4D CTs to characterize endoleaks in branched and fenestrated endovascular aortic repair (FB-EVAR). The 4D CTs were performed covering up to 16 cm of the z-axis, with anywhere between 10 and 40 iterations performed every 2 s. These settings were adjusted depending on graft characteristics and type of endoleak suspected. The scans were assessed for their ability to detect the endoleak (sensitivity), and further to characterize the endoleak by type and subtype (specificity). RESULTS: Overall sensitivity in 16 scans for endoleak detection was 100%. There was a specificity of 87.5% for determining the type of endoleak (14/16). These results included two studies that were inconclusive and repeated due to technical difficulties. In patients where a specific subtype was not established, the leak was localized to the appropriate target vessel. Average dose for the 4D CT was 4724 mGy*cm (1108-11069), with the outlining higher dose scans secondary to higher iterations in those scans. CONCLUSIONS: 4D CT is a useful adjunctive tool in FB-EVAR surveillance with excellent sensitivity and specificity in characterizing endoleaks. This allows for accurate localization of leaks, which is critical for management planning.

Typology, Severity, and Outcomes of Adverse Events Related to Angiographic Equipment-A Ten-Year Analysis of the FDA MAUDE Database.

Purpose: Angiographic equipment is a key component of healthcare infrastructure, used for endovascular procedures throughout the body. The literature on adverse events related to this technology is limited. The purpose of this study was to analyze adverse events related to angiographic devices from the US Food and Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database. Methods: MAUDE data on angiographic imaging equipment from July 2011 to July 2021 were extracted. Qualitative content analysis was performed, a typology of adverse events was derived, and this was used to classify the data. Outcomes were assessed using the Healthcare Performance Improvement (HPI) and Society of Interventional Radiology (SIR) adverse event classifications. Results: There were 651 adverse events reported. Most were near misses (67%), followed by precursor safety events (20.5%), serious safety events (11.2%), and unclassifiable (1.2%). Events impacted patients (42.1%), staff (3.2%), both (1.2%), or neither (53.5%). The most common events associated with patient harm were intra-procedure system shut down, foot pedal malfunction, table movement malfunction, image quality deterioration, patient falls, and fluid damage to system. Overall, 34 (5.2%) events were associated with patient death; 18 during the procedure and 5 during patient transport to another angiographic suite/hospital due to critical failure of equipment. Conclusion: Adverse events related to angiographic equipment are rare; however, serious adverse events and deaths have been reported. This study has defined a typology of the most common adverse events associated with patient and staff harm. Increased understanding of these failures may lead to improved product design, user training, and departmental contingency planning.

Effect of vertebral compression fractures on aortic neck angulation after endovascular aneurysm repair.

OBJECTIVE: Aortic neck angulation (ANA) prior to endovascular aneurysm repair (EVAR) and its changes after EVAR are considered important predictors of postoperative complications. We sought to assess the effects of vertebral body height loss on ANA in patients post-EVAR. METHODS: All patients who had undergone EVAR for infrarenal aortic aneurysms in our institution between August 2010 and December 2018 were assessed. Anterior and posterior vertebral body heights were measured in all patients on preoperative, early postoperative, and follow-up computed tomography scans (T12-L5 vertebral bodies). Patients who had significant height loss in their follow-up period were designated as the Study group. These were matched to a Control group of the same size using propensity-score matching based on age, gender, and duration between follow-up scans. Aortic neck morphology indices including ANA and its changes were measured, and information related to postoperative endoleaks and aneurysm sac size were extracted in the Study and Control groups. RESULTS: During the follow-up period, 10 of 185 patients had a radiologically significant vertebral body compression fracture. There was no significant difference between the Study (n = 10) and Control groups in age (77.6 ± 6.9 vs 77.2 ± 7.5 years; P = .64), gender (seven males and three females in each group; P = 1.0), duration between postoperative scans (1830 ± 665 vs 1800 ± 670 days; P = .25), preoperative ANA (36.0° ± 15.6° vs 42.4° ± 18.6°; P = .41), and early postoperative ANA (21.9° ± 11.7° vs 20.9° ± 16.3°; P = .72). Changes in ANA in the postoperative period (7.2° ± 11.1° vs -4.7° ± 6.7°; P = .009; power = .838) were significantly higher in the Study group. CONCLUSIONS: Post-EVAR vertebral body compression fractures exacerbate ANA. Awareness of this can guide both preoperative assessment and postoperative management and follow-up.

Percutaneous Transluminal Angioplasty for Below-the-Elbow Critical Hand Ischemia: A Systematic Review.

PURPOSE: To perform a systematic review assessing the safety and efficacy of percutaneous transluminal angioplasty (PTA) for treatment of critical hand ischemia (CHI) due to below-the-elbow (BTE) obstructive arterial disease. MATERIALS AND METHODS: MEDLINE and EMBASE systematic searches were performed from inception to December 2020 to identify studies assessing PTA for management of BTE obstructive arterial disease. Three independent reviewers performed abstract selection, data extraction, and quality assessment. The Newcastle-Ottawa Scale was used to assess individual study bias for non-randomized controlled trials. RESULTS: Eight studies comprising 176 patients with obstructive BTE vessel disease were included. All studies had a score >5 on the Newcastle-Ottawa Scale, indicative of high quality. All studies used low-profile balloons (1.5-4 mm) for PTA of stenotic lesions or chronic total occlusions (CTOs). The weighted average technical success and clinical success rates were 89.3% (range = 82%-100%) and 69.9% (range = 19%-100%), respectively, at a mean follow-up of 29.7 ± 17.1 months. The short-term (<30 days) complication rate was low at 4.7% and most commonly included access site hematomas, pseudoaneurysms, and radial artery perforation or re-thrombosis. Nearly 20% of patients required an amputation, and most (96%) were minor (either distal phalanges or digits). Only 2 patients required above-wrist amputations. The primary and secondary patency rate at 5 years were 38% and 54%, respectively. The cumulative 5-year mortality rate was 33.1%. CONCLUSIONS: PTA for CHI due to BTE obstructive arterial disease is feasible with a high technical success rate and a low short-term complication rate. Additional long-term comparative studies are required to unequivocally establish the clinical benefit of endovascular treatment compared with conservative management or surgical bypass.

Uterine Artery Embolization for Pedunculated Subserosal Fibroids: A Systematic Review and Meta-Analysis.

PURPOSE: To provide a comprehensive overview of the literature assessing the safety and efficacy of uterine artery embolization (UAE) for patients with pedunculated subserosal fibroids. MATERIALS AND METHODS: MEDLINE and Embase databases were searched without language or publication type restrictions for observational studies to estimate safety (adverse events) and efficacy (devascularization, fibroid volume reduction, and uterine volume reduction) outcomes. Case reports were included to qualitatively report adverse events. Meta-analysis was performed for single proportions and mean changes with random-effects modeling. RESULTS: Of 98 eligible articles, 11 studies were included in the final analysis. Of the adverse events detailed in these cases, 5 events were mild, 2 were moderate (torsion of pedunculated fibroid requiring laparoscopic myomectomy and persistent bleeding after embolization requiring hysterectomy), and 1 was severe (fibroid necrosis causing bowel obstruction requiring bowel resection and hysterectomy). There were no deaths reported in the literature. The pooled risk of adverse events was 1.7% (95% confidence interval [CI], 0.29%-9.2%; 4 of 181; I2 = 0%). The pooled devascularization rate was 75.9% (95% CI, 62.4%-85.6%; 140 of 189; I2 = 75%) at 3.91 months of follow-up. The percent volume reduction of the dominant pedunculated fibroid was 38.6% (95% CI, 33.0%-44.2%; I2 = 0%) at 4.3 months of follow-up. The percent uterine volume reduction was 36.7% (95% CI, 30.3%-43.0%; I2 = 47%) at 3.5 months of follow-up. CONCLUSIONS: UAE for pedunculated subserosal fibroids has a low risk of adverse events and effectively reduces fibroid and uterine size.

Safety of High-Dose 3% Sodium Tetradecyl Sulfate for Sclerotherapy of Renal Cysts in Patients with Autosomal Dominant Polycystic Kidney Disease.

This study assessed the safety profile of high-volume (>10 mL) 3% sodium tetradecyl sulfate (STS) sclerotherapy for the treatment of renal cysts in patients with autosomal dominant polycystic kidney disease. A total of 211 sclerotherapy treatments were performed in 169 patients over a 5-year period, with a comparison of 2 patient cohorts based on the STS volumes used. The first cohort (n = 112) received a high volume (greater than 10 mL) of STS, and the second cohort (n = 57) received a low volume (less than 10 mL). The minor adverse event rate for the cohorts was 14.5% and 9.6%, respectively (P = .310), with postprocedure pain being the most common event. One major adverse event occurred, for which the patient required hospitalization for infection after low-volume STS treatment. Doses of STS higher than those currently recommended by the Food and Drug Administration for intravascular use allow large renal cysts to be treated safely in the setting of autosomal dominant polycystic kidney disease.

Endovascular coil embolization of inferior mesenteric artery to ileal-conduit fistula: a case report.

BACKGROUND: Uretero-arterial fistulas (UAFs) are uncommon and pose a diagnostic dilemma, making them life threatening if not recognized and treated expediently. UAFs to small arteries such as a branch of the inferior mesenteric artery (IMA) are very uncommon and present a further diagnostic and treatment challenge. There should be a high index of suspicion for UAFs when intervening on patients with history of treated pelvic cancers and long-standing ureteric stents experiencing hematuria not attributable to another cause. CASE PRESENTATION: We present a case of a fistula formed between a distal branch of the IMA-superior rectal artery-and an ileal-conduit in a patient with a long-standing reverse nephroureterostomy (Hobbs) catheter presenting with abdominal pain and hematuria through the conduit. During a tube exchange, contrast injection demonstrated a fistula with the superior rectal artery, multiple ileal intraluminal blood clots, and active extravasation. The patient became tachycardic and hypotensive, actively bleeding through the ileal-conduit, prompting a massive transfusion protocol. Successful endovascular coiling of the superior rectal artery was performed with resolution of active extravasation and stabilization of the patient. The patient recovered and was discharged in stable condition 10 days later. CONCLUSIONS: Although UAFs are uncommon, our case demonstrated key predisposing risk factors to fistula development; pelvic cancer surgery, pelvic radiation, and a prolonged ureteric stent through the ileal-conduit. Typically, UAFs arise from communication with the iliac arterial system, however in this instance we have demonstrated that fistulization to other arterial vessels is also possible. Endovascular management has become the preferred method of therapy, typically involving the placement of covered stents when involving the iliac arterial system. In this instance stent grafting was not possible due to the small caliber vessel and therefore had to be embolized.

Arteries of the Lower Limb-Embryology, Variations, and Clinical Significance.

OBJECTIVES: The purpose of this article is to review the embryology of the lower limb arterial anatomy along with common variants and their clinical relevance. DESIGN: Embryologic variations of the lower limb arterial system may be explained by i.) persistence of primordial arterial segments, ii.) abnormal fusion, iii.) segmental hypoplasia/absence, or a combination of both. Persistent sciatic artery, corona mortis, and popliteal entrapment syndrome will also be discussed with associated symptoms, and potential complications. CONCLUSION: Knowledge of these variations is essential for surgical and endovascular management as failure to recognize them can result in complications.

Complication rates associated with antegrade use of vascular closure devices: a systematic review and pooled analysis.

BACKGROUND: Vascular closure devices (VCDs) have become a mainstay in endovascular interventions in recent years. On-label use only allows for retrograde interventions originating at the common femoral artery (CFA). However, off-label use in antegrade and/or superficial femoral artery (SFA) access has become more common in the treatment of peripheral arterial disease. Despite this, there is a paucity of comparative literature assessing individual VCD safety profiles and relative complication risks of CFA vs SFA applications. METHODS: MEDLINE and EMBASE systematic searches were performed from inception to October 2019 to identify studies assessing VCD use in antegrade CFA and SFA interventions. Abstract selection and data extraction were performed by two independent reviewers. Primary outcomes included bleeding-related complications, vessel occlusion or stenosis, embolization, pseudoaneurysm formation, or arteriovenous fistula formation. RESULTS: Twenty-four unique studies with 4124 vascular closure events via six unique VCDs were included (Angioseal, Exoseal, Femoseal, Glubran 2, Mynx, Starclose; 3698 CFA, 426 SFA). Pooled occurrence of all complications across closure devices used in the CFA and SFA ranged from 0.9% (Mynx) to 7.4% (Starclose) and 0% (Perclose) to 10.1% (Starclose), respectively, depending on VCD type. Clinically meaningful differences were identified between devices with a trend toward significance (P = .08 CFA, P = .07 SFA). Individual devices demonstrated a range of bleeding complication rates from 0.4% (Mynx) to 7.2% (Femoseal) for the CFA site and from 0% (Perclose) to 6.4% (Starclose) for the SFA site (P = .01 and P = .03, respectively). Significant heterogeneity between studies precludes definitive characterization of the device as cause for variations in bleeding complication rates. Pooled complication rates did not differ between the CFA and SFA arms (4.6% vs 5.8%, P = .56). Bleeding complication rates also did not differ between the CFA and SFA arms (3.6% vs 3.6%, P = .98). CONCLUSIONS: Clinically meaningful differences in overall pooled complications were identified between VCDs with a trend toward significance. Significant differences between VCDs exist with respect to bleeding risk. However, this must be interpreted with caution as these differences could be secondary to interstudy heterogeneity. Finally, no difference was identified between antegrade SFA and CFA VCD use with respect to overall complication and bleeding risks.

Overall Impact of the COVID-19 Pandemic on Interventional Radiology Services: A Canadian Perspective.

PURPOSE: The aim of this national survey was to assess the overall impact of the coronavirus disease 2019 (COVID-19) pandemic on the provision of interventional radiology (IR) services in Canada. METHODS: An anonymous electronic survey was distributed via national and regional radiology societies, exploring (1) center information and staffing, (2) acute and on-call IR services, (3) elective IR services, (4) IR clinics, (5) multidisciplinary rounds, (6) IR training, (7) personal protection equipment (PPE), and departmental logistics. RESULTS: Individual responses were received from 142 interventional radiologists across Canada (estimated 70% response rate). Nearly half of the participants (49.3%) reported an overall decrease in demand for acute IR services; on-call services were maintained at centers that routinely provide these services (99%). The majority of respondents (73.2%) were performing inpatient IR procedures at the bedside where possible. Most participants (88%) reported an overall decrease in elective IR services. Interventional radiology clinics and multidisciplinary rounds were predominately transitioned to virtual platforms. The vast majority of participants (93.7%) reported their center had disseminated an IR specific PPE policy; 73% reported a decrease in case volume for trainees by at least 25% and a proportion of trainees will either have a delay in starting their careers as IR attendings (24%) or fellowship training (35%). CONCLUSION: The COVID-19 pandemic has had a profound impact on IR services in Canada, particularly for elective cases. Many centers have utilized virtual platforms to provide multidisciplinary meetings, IR clinics, and training. Guidelines should be followed to ensure patient and staff safety while resuming IR services.

Primary venous aneurysms: A 20-year retrospective analysis.

OBJECTIVE: Primary venous aneurysms are unusual vascular occurrences. Our aim is to document our institution's experience with this pathology; describing frequency, diagnosis, outcomes and medical histories of patients with primary venous aneurysms within a 20-year time frame. METHODS: A retrospective study at our institution using its radiology database was conducted. Results were isolated to primary venous aneurysms diagnosed between 1997 and 2017. Basic demographics and medical history were collected. RESULTS: We identified 32 patients with primary venous aneurysms. Eighteen were male and 14 were female. The average age of presentation was 54 years old, with a range of 17-86. None of these patients reported a family history of aneurysmal disease. The majority were incidental. Of these aneurysms, 3 were of the head and neck, 1 was contained in the thorax, 17 were intra-abdominal and 11 were peripheral. Diagnosis was made by computed tomography, duplex ultrasound, or magnetic resonance imaging. Conservative management was most frequently employed, but four patients underwent surgical repair. Three aneurysms required operation for symptom management (external jugular, subclavian, inferior vena cava), whereas one aneurysm of the popliteal vein was prophylactically managed, given the high risk for pulmonary embolism. CONCLUSIONS: Primary venous aneurysms present infrequently. Despite their rarity, primary venous aneurysms have been reported to occur throughout the venous system. The majority of primary venous aneurysms in this series were found incidentally and can present both symptomatically or asymptomatically. The findings of our 20-year experience were consistent with the existing literature. Because the risk of rupture is negligible, the indications for surgical management remain for cosmesis, symptom management or high risk of thromboembolic events.

IVC filter removal after extended implantation periods.

OBJECTIVE: Life-threatening complications have been reported in patients with chronic retrievable IVC filters. National health agencies have urged hospitals to assess all patients with retrievable IVC filters for filter removal. The aim of the current study was to identify those patients with unretrieved chronic IVC filters, document complications and removal techniques. METHODS: We identified a cohort with unretrieved IVC filters inserted between January 2001 and December 2013. These patients were invited back to clinic for review with CT imaging to determine complications, if any, and offer removal. Data collected included demographics, complications and retrieval characteristics. RESULTS: 289 patients were discovered to still have a filter in situ. Of these, 193 patients were verified as deceased. Eighty-nine patients were notified, with no current contact information available on the remaining seven. Thirty-six attended for review, 20 females, 16 males, with an average age of 63.5 years. Complications identified at CT were 2 occluded IVCs (5.8%), 4 fractured filters (11.7%) and filter penetration in all cases (37.5% grade 2, 56.25% grade 3). Sixteen patients agreed to proceed with filter removal, 10 declined the opportunity and 6 were unfit or had ongoing indication for the filter. Two are awaiting removal and two had IVC occlusion. Subsequent retrieval was successful in 93% of cases (14/15). The mean time to removal from implant was 3846.9 days (SD 980.3). Advanced techniques were utilized in 10 cases and there were no mortalities or morbidities. CONCLUSION: Retrievable inferior vena cava filters are not benign and practitioners need to be aware of regulatory guidelines. Unretrieved filters can be successfully retrieved using standard and advanced methods with low morbidity and mortality.

Sources of Error in Interventional Radiology: How, Why, and When

This article aims to provide an overview of the sources for error in interventional radiology (IR). Being both a procedure and an imaging-based specialty, IR has unique considerations as to how error can occur. However, compared to the surgical and medical literature, data on error in IR are lacking. The available IR literature is reviewed but supplemented with lessons from other specialties and the World Health Organization. Individual risks such as cognitive bias as well as system-level factors are also considered in order to generate a taxonomy for error in IR that includes the operator, patient, team, and environment.

Drug-Coated Balloon Angioplasty in Hemodialysis Circuits: A Systematic Review and Meta-Analysis.

PURPOSE: To perform a systematic review and meta-analysis assessing patency outcomes following drug-coated balloon angioplasty (DCBA) in hemodialysis circuits. MATERIALS AND METHODS: MEDLINE and EMBASE systematic searches were performed from inception to November 2018 to identify comparative studies assessing DCBA vs plain old balloon angioplasty (POBA) in hemodialysis circuits. Abstract selection, data extraction, and quality assessment were performed by 2 independent reviewers. Primary outcome was loss of target lesion patency at 3, 6, 12, and 24 months for autogenous arteriovenous fistula (AVF), prosthetic arteriovenous graft (AVG), and hemodialysis-related central venous stenosis. RESULTS: Twelve studies comprising 908 patients were included. There was a significant improvement in patency among AVF after DCBA vs POBA at 3, 6, 12, and 24 months (odds ratio 0.58 [95% confidence interval, 0.36-0.94]; odds ratio 0.40 [95% confidence interval 0.23-0.70]; odds ratio 0.39 [95% confidence interval, 0.25-0.61]; and odds ratio 0.20 [95% confidence interval, 0.07-0.62]). This benefit persisted on subgroup analysis of randomized controlled trials (RCTs) only. Meta-analysis of results specific to AVG could not be performed, as only 1 RCT was identified that favored DCBA. Hemodialysis-associated central vein stenosis did not demonstrate a significant difference in patency rates between DCBA and POBA on meta-analysis. Twelve-month mortality and same-day complication rates did not differ between arms. CONCLUSIONS: Significant improvement in patency was identified with DCBA in AVF at 3, 6, 12, and 24 months. A single comparative study identified benefit of DCBA use in the AVG group. No significant benefit was identified with DCBA for central stenosis.