Contemporary Management of Acute Pulmonary Embolism: Evolution of Catheter-based Therapy.

Acute pulmonary embolism (PE) affects more than 100 000 people in the United States annually and is the third leading cardiovascular cause of death. The standard management for PE is systemic anticoagulation therapy. However, a subset of patients experience hemodynamic decompensation, despite conservative measures. Traditionally, these patients have been treated with systemic administration of thrombolytic agents or open cardiac surgery, although attempts at endovascular treatment have a long history that dates back to the 1960s. The technology for catheter-based therapy for acute PE is rapidly evolving, with multiple devices approved over the past decade. Currently available devices fall into two broad categories of treatment methods: catheter-directed thrombolysis and percutaneous suction thrombectomy. Catheter-directed thrombolysis is the infusion of thrombolytic agents directly into the occluded pulmonary arteries to increase local delivery and decrease the total dose. Suction thrombectomy involves the use of small- or large-bore catheters to mechanically aspirate a clot from the pulmonary arteries without the need for a thrombolytic agent. A thorough understanding of the various risk stratification schemes and the available evidence for each device is critical for optimal treatment of this complex entity. Multiple ongoing studies will improve our understanding of the role of catheter-based therapy for acute PE in the next 5-10 years. A multidisciplinary approach through PE response teams has become the management standard at most institutions. An invited commentary by Bulman and Weinstein is available online. Online supplemental material is available for this article. ©RSNA, 2022.

Balloon-Occluded Transarterial Chemoembolization for the Treatment of Hepatocellular Carcinoma: A Single-Center US Preliminary Experience.

This report describes a single-center experience with balloon-occluded transarterial chemoembolization for liver-directed therapy. A total of 26 patients (11 male, 4 female; mean age, 65 y ± 7) with 28 tumors (mean diameter, 2.7 cm; range, 1.1-5.9 cm) were treated. Technical success rate was 100% (28 of 28 cases), with 1 minor complication of left portal vein thrombosis and small liver infarct. Of the 15 tumors analyzed for response, 60% (9 of 15) exhibited complete response, 33.3% (5 of 15) exhibited partial response, and 6.6% (1 of 15) had stable disease on follow-up. Eight patients exhibited overall progression with a new hepatic lesion and a median time to progression of 7.9 months (range, 5-11 mo).

Current Concepts and Future Directions of Minimally Invasive Treatment for Knee Pain.

PURPOSE OF REVIEW: The purpose of this paper is to review the percutaneous interventions available for the treatment of osteoarthrosis of the knee that address pain and prolong the time to arthroplasty. RECENT FINDINGS: Corticosteroid injection and viscosupplementation have been the most studied, but there is still no consensus about their value. Thermal nerve ablation, including both radiofrequency ablation and cryoneurolysis, is a promising new modality of therapy that may increase in clinical use given current data showing favorable outcomes. Of the future therapies that are currently under investigation, synovial embolization via the geniculate arteries represents an exciting new approach that may soon be available clinically. There are various percutaneous interventions available for the treatment of osteoarthrosis of the knee that address pain and prolong the time to arthroplasty.

Endovascular Alternatives to Transhepatic Shunt Creation.

Portomesenteric decompression is often necessary to treat patients with refractory symptoms of portal hypertension. When transjugular or direct intrahepatic portosystemic shunt creation is not feasible or is inadequate, surgical portosystemic shunt creation is considered, which carries significant morbidity and mortality in these high-risk patients. Surgery is further complicated in patients with portomesenteric thrombosis who require concurrent thrombectomy and long-term anticoagulation. In this article, we outline the technique for performing advanced endovascular alternatives to intrahepatic portosystemic shunt creation including mesocaval and splenorenal shunting. We will also discuss some of the clinical considerations for treating these patients with symptomatic portal hypertension and portomesenteric thrombosis.

Advanced Techniques for Accessing the Portal Vein during Transjugular Intrahepatic Portosystemic Shunt Creation.

Transjugular portosystemic shunt (TIPS) placement is a widely accepted method for reducing portal pressures in conditions including symptomatic varices, refractory ascites, hepatic hydrothorax, portomesenteric thrombosis, and Budd-Chiari syndrome. The traditional method for performing TIPS involves "blind" access into a portal vein branch from a hepatic vein, typically right portal vein to right hepatic vein, using preoperative imaging and intraoperative wedged portography for guidance. However, standard access technique may not always be feasible due to occluded portal or hepatic veins, distorted anatomy, or prior TIPS. In this article we discuss alternative techniques for accessing the portal vein for TIPS placement when standard methods are not sufficient.

Leveraging the virtual learning environment to enhance medical student engagement with interventional radiology.

PURPOSE: To evaluate medical student engagement with Interventional Radiology (IR) before and after a virtual elective course. METHODS: The elective was nine, one-hour lectures over ten weeks. An anonymous pre and post-course survey was administered to students. The hypothesis was that this course would increase student engagement with IR. Respondents answered nine questions to score their interest in, exposure to, familiarity with, and understanding of IR using a five-point Likert scale. Demographics were reported for the pre-course group only. A Wilcoxon signed-ranked test was performed to assess for significant mean change in pre and post-course responses. Among the 276 registered students, there were 144 individual, complete responses for the pre-course survey, and 60 paired responses for both surveys. RESULTS: Thirty-seven percent of respondents were first or second year medical students. Thirty percent of participants were enrolled at an institution outside of the United States, 26% are the first in their family to attend college, and 41% identified as female. Thirty-six percent reported this virtual course was one of their earliest experiences with IR. There was a significant increase in student exposure to IR generally, familiarity with IR compared to other specialties, familiarity with the IR training pathway(s), understanding of what an Interventional Radiologist does, understanding of the difference between IR and Diagnostic Radiology, and understanding of when to consult IR for patient care after completion of the course. CONCLUSION: A virtual IR elective is an effective means to increase exposure to, familiarity with, and understanding of IR.

Additional Magnetic Resonance or Nuclear Scintigraphy Imaging Influences Approach to Vertebral Augmentation: A Single Institution Experience.

STUDY DESIGN: Retrospective review. OBJECTIVE: To ascertain impact of preprocedural magnetic resonance imaging (MRI) or nuclear medicine Tc99m-DMP scintigraphy on the treatment plan when compared with plain films and/or computed tomography prior to vertebral augmentation procedures. SUMMARY OF BACKGROUND DATA: Over 1 million vertebral compression fractures (VCFs) occur in the United States annually with over 150,000 individuals hospitalized each year. Physical examination and history are essential to the workup of VCFs, but imaging remains necessary for confirming the diagnosis. VCFs can be imaged with various modalities and there is limited data on the comparative effectiveness of different imaging modalities. METHODS: Six hundred fifty consecutive patients treated with vertebral augmentation at a single institution between May of 2013 and April of 2018 were reviewed. Preprocedure imaging of the spine obtained within 30 days prior to the procedure were reviewed. Preprocedure imaging results were cross-referenced against the levels treated by vertebral augmentation to determine whether there was a change in the levels treated after receiving an MRI or NM imaging study. RESULTS: Three hundred sixty-three patients had adequate imaging for inclusion. One hundred fifty-four of these 363 patients (42.4%) had an alteration of their treatment plan based upon the MR or NM imaging. Fewer vertebral levels were treated in 33, different levels were treated in 41, and more levels were treated in 80 patients. CONCLUSION: MRI or nuclear medicine bone scan imaging prior to vertebral augmentation altered the location and number of levels treated in a large percentage of patients, adding specificity to treatment over findings on radiographs or computed tomography alone. LEVEL OF EVIDENCE: 3.

Extreme obesity is associated with angulation during inferior vena cava filter placement.

BACKGROUND: Placement of inferior vena cava (IVC) filters can be complicated by venous injury, filter misplacement, angulation, insertion site injury, and procedure-related death. Currently, no studies exist evaluating the correlation between obesity and adverse outcomes of IVC filters. We aimed to assess the outcomes of IVC filter placement in the obese population using the Vascular Quality Initiative database. METHODS: The Vascular Quality Initiative registry identified 7258 patients who underwent IVC filter placement from January 2013 to June 2017. Patients were divided into three groups based on their body mass index (BMI): normal/overweight (BMI <30), obese (BMI 30-40), and extremely obese (BMI >40). Periprocedural outcomes were analyzed. RESULTS: The mean age was 63.6 ± 16.6 years and 3444 patients (47%) were female. BMI was less than 30 in 4115 (56.7%), 30 to 40 in 2148 (29.6%), and greater than 40 in 995 (13.7%) patients. A complication or IVC filter-related death occurred in 142 patients (2.6%). Adverse events included angulation (1.3%), IVC filter misplacement (0.5%), insertion site injury (0.3%), IVC filter-related death (0.1%), and venous injury (0.06%). In multivariable analysis, increased BMI was found to be associated with angulation (P = .03), but was not associated with IVC filter misplacement (P = .43), or any complication or IVC filter-related death (P = .22). A subgroup analysis of IVC filter placements using only fluoroscopy demonstrated that the risk of angulation was significantly higher in patients with a BMI of greater than 40 compared with a BMI of less than 30 (odds ratio, 2.12; 95% confidence interval, 1.07-4.21; P = .03). There was not enough evidence to conclude that BMI was associated with any other outcome. CONCLUSIONS: IVC filter insertion has low complication rates. Increased BMI is associated with an increased risk of IVC filter angulation; there is no evidence of association between BMI and other periprocedural complications.

Tc-99m-MAA lung shunt fraction before Y-90 radioembolization is low among patients with non-hepatocellular carcinoma malignancies.

OBJECTIVE: Lung shunt fraction studies using technetium-99 m macro aggregated albumin are routinely performed before yttrium-90 radioembolization regardless of underlying liver malignancy type. This study evaluates the role of lung shunt fraction studies in hepatocellular carcinoma compared to non-hepatocellular carcinoma liver tumors. METHODS: A single-institution retrospective analysis of all pre-yttrium-90 technetium-99 m macro aggregated albumin lung shunt fraction studies between November 2012 to March 2018 was performed. Patient variables including age, underlying malignancy, laboratory values, lung shunt fraction, and severity of liver disease were compared between hepatocellular carcinoma and non-hepatocellular carcinoma cases. RESULTS: A total of 734 technetium-99 m macro aggregated albumin studies were identified in 653 patients. Among these cases, the liver tumor was hepatocellular carcinoma in 368 (50.1%), colorectal cancer in 112 (15.3%), neuroendocrine tumor in 89 (12.1%), cholangiocarcinoma in 59 (8.0%), breast cancer in 27 (3.7%), and other metastatic malignancies in 79 (10.7%). The mean lung shunt fraction for non-hepatocellular carcinoma cases was 7.4%, which was significantly lower than the mean lung shunt fraction, 11.7%, for hepatocellular carcinoma cases (P = 0.0001). In only one non-hepatocellular carcinoma case was yttrium-90 radioembolization not pursued due to high lung shunt fraction (69.3%), wherein large scale shunting was grossly apparent on angiography in a patient with metastatic gastrointestinal stromal tumor. In comparison, the lung shunt fraction was too high to pursue radioembolization in 37 hepatocellular carcinoma cases (mean lung shunt fraction 35.1%). CONCLUSION: Lung shunt fraction appears low among patients with non-hepatocellular carcinoma liver malignancies. Further analysis examining the necessity of pre-Y90 technetium-99 m macro aggregated albumin lung shunt fraction studies in patients with non-hepatocellular carcinoma malignancies is warranted, since a consolidated yttrium-90 radioembolization without prior lung shunt fraction evaluation could reduce resource consumption, improve workflows, and patient access.

The State of Medical Student Teaching of Interventional Radiology: Implications for the Future.

INTRODUCTION: The formation of integrated interventional radiology (IR) residency programs has changed the training paradigm. This change mandates the need to provide adequate exposure to allow students to explore IR as a career option and to allow programs to sufficiently evaluate students. This study aims to highlight the availability of medical student education in IR and proposes a basic framework for clinical rotations. MATERIALS AND METHODS: The Liaison Committee on Medical Education (LCME) website was utilized to generate a list of accredited medical schools in the United States. School websites and course listings were searched for availability of IR and diagnostic radiology rotations. The curricula of several well-established IR rotations were examined to identify and categorize course content. RESULTS: In all, 140 LCME-accredited medical schools had course information available. Of those schools, 70.5% offered an IR rotation; 84.6% were only available to senior medical students and only 2% were offered for preclinical students; and 8.1% of courses were listed as subinternships. Well-established IR clerkships included a variety of clinical settings, including preprocedure evaluation, experience performing procedures, postprocedure management, and discharge planning. CONCLUSION: Medical student exposure to IR is crucial to the success of integrated IR residency programs. Current research shows few institutions with formal IR subinternship rotations. Although 70.5% of institutions have some form of nonstandardized IR course, 84.6% are available only to fourth-year students, and 2% are offered to preclinical students. This suggests there is a significant opportunity for additional formal exposure to IR through increasing availability of IR rotations and exposure during the clinical and preclinical years.