Added Value of Cone-Beam CT to Identify Arterial Supply during Genicular Artery Embolization for Knee Osteoarthritis.

PURPOSE: To evaluate if the addition of cone-beam computed tomography (CT) to digital subtraction angiography (DSA) improves the identification of the genicular arteries during genicular artery embolization (GAE) for knee pain secondary to osteoarthritis (OA). MATERIALS AND METHODS: This single-center study retrospectively analyzed 222 patients who underwent GAE for painful knee OA between May 2018 and April 2022. Intraprocedural cone-beam CT and DSA images were reviewed independently by 2 sets of interventional radiologists. DSA was performed for all patients. Technically adequate cone-beam CT was available for 205 patients (92.3%). The presence of the genicular arteries identified by cone-beam CT and DSA was compared using Φ coefficients. Embolization targets identified by both cone-beam CT and DSA were evaluated against those identified by DSA alone. RESULTS: Genicular arteries with the highest concordance between cone-beam CT and DSA were the inferior lateral (196 vs 198; Φ = 0.3530; P < .0001), superior lateral (197 vs 200; Φ = 0.3060; P < .0001), and superior medial genicular (186 vs 161; Φ = 0.2836; P < .0001) arteries. Cone-beam CT demonstrated higher rates of detection of the inferior medial (195 vs 178; Φ = 0.04573; P = .5150) and median genicular arteries (200 vs 192; Φ = 0.04573; P = .5150). Meanwhile, genicular arteries less frequently identified by cone-beam CT were the descending genicular (197 vs 200; Φ = -0.03186; P = .6502), superior patellar (175 vs 184; Φ = 0.1332; P = .0569), and recurrent anterior tibial (156 vs 186; Φ = 0.01809; P = .7969) arteries. Cone-beam CT in combination with DSA identified 13.4% (372 vs 328) more targets compared to DSA alone. CONCLUSIONS: Based on the results of the current study, cone-beam CT serves as a valuable adjunct for visualizing the genicular arteries during GAE, and together with DSA, it identifies more potential embolization targets.

Classification of Genicular Artery Anatomic Variants Using Intraoperative Cone-Beam Computed Tomography.

PURPOSE: Genicular artery embolization (GAE) is a new treatment option for symptomatic knee osteoarthritis. Genicular arterial anatomy is complex with limited published reports. This study describes the genicular artery anatomy utilizing intraprocedural cone-beam computed tomography (CBCT) during GAE. MATERIALS AND METHODS: This retrospective single-center study was approved by the institutional review board. All patients who underwent GAE between May 2018 and April 2022 were reviewed. Patients with a technically adequate CBCT were included in the analysis. CBCTs were analyzed to determine the presence, course, and branching patterns of the genicular arteries. RESULTS: A total of 222 patients underwent GAE and 205 (92%) were included for analysis. The descending genicular artery was present in 197 (96%) CBCTs with two branches in 152 (77%). The superior medial genicular artery (SMGA) was present in 186 (91%), superior lateral genicular artery (SLGA) in 203 (99%), inferior medial genicular artery (IMGA) in 195 (95%), inferior lateral genicular artery (ILGA) in 196 (95%), and median genicular artery (MGA) in 200 (97%). Four unique branching patterns were identified: common origin of SLGA and MGA (115, 56%), unique origins (45, 22%), trifurcation of SLGA, SMGA, and MGA (32, 15.5%), and common origin of SMGA and MGA (12, 6%). The recurrent ascending tibial was identified in 156 (76%) CBCTs and superior patellar artery in 175 (85%) CBCTs. CONCLUSION: Genicular artery anatomy is complex with numerous common variants. CBCT is a powerful adjunct in GAE to rapidly identify target vessels for embolization and potentially decrease the risk of nontarget embolization.

Design of a High-Flow Catheter Connector to Enhance Fluid Transfer.

PURPOSE: To compare the performance of a prototype high-flow catheter connector, the Lamprey Lock, with that of a conventional Luer connector. MATERIALS AND METHODS: The Lamprey Lock was created to eliminate the choke point resulting from Luer connections by achieving a cross-sectional area approximately 2.5 times larger than that achieved by a conventional Luer connector. A Lamprey Lock 3-way connector was also created by expanding the inner channels of a traditional Luer 3-way connector and exchanging the male Luer connection with a Lamprey Lock connection. These were tested against unaltered Luer and Luer 3-way connectors to compare flow rates using in vitro models of serous and purulent fluid. Each experimental condition was repeated 5 times. RESULTS: In the serous model, the mean drainage rate was 4.4 mL/s (95% CI, 4.3-4.6) and 3.3 mL/s (95% CI, 3.3-3.5) for the Lamprey Lock and Luer connector, respectively (P < .001). The mean drainage rate was 4.2 mL/s (95% CI, 3.9-4.5) and 2.7 mL/s (95% CI, 2.5-2.8) for the Lamprey Lock 3-way and Luer 3-way connector, respectively (P < .001). In the purulent model, the mean drainage rate was 1.4 mL/min (95% CI, 1.3-1.6) and 0.75 mL/min (95% CI, 0.68-0.82) for the Lamprey Lock and Luer connector, respectively (P < .001). The mean drainage rate was 1.5 mL/min (95% CI, 1.3-1.7) and 0.74 mL/min (95% CI, 0.70-0.78) for the Lamprey Lock 3-way and Luer 3-way connector, respectively (P < .001). CONCLUSIONS: The proposed high-flow catheter connector, the Lamprey Lock, demonstrated higher flow rates than those demonstrated by a conventional Luer connector in vitro.

AngioVac Aspiration Thrombectomy of Right Atrial Thrombus is Safe and Effective in Cancer Patients.

OBJECTIVES: The aim of this study was to test the hypothesis that endovascular aspiration thrombectomy of right atrial thrombus (RAT) using the AngioVac device is as safe and effective in patients with cancer as those without cancer. BACKGROUND: RAT is a uniquely challenging clinical presentation of venous thromboembolism due to its low incidence and historically high-risk of mortality due to thrombus propagation into the pulmonary arteries. There is a lack of consensus regarding management, particularly in high-risk cancer patients. Endovascular aspiration thrombectomy utilizing the AngioVac device is effective in removal of right atrial thrombus and may be a safer option for patients with cancer in whom avoidance of higher-risk intervention is preferred. METHODS: This was an institutional review board-approved retrospective single-center case control study of patients with RAT who underwent AngioVac aspiration thrombectomy between August 2013 and July 2020. Analysis of patient demographics and clinical characteristics, thrombus-related factors, and operative details was performed. Primary endpoints included survival, safety, and technical success. RESULTS: A total of 44 patients met inclusion criteria, 20 of whom with active malignancy. The oncology group had a significantly higher Charlson comorbidity index (P = 0.01). Comparative outcomes between the oncology and non-oncology group showed no difference in survival (P = 0.8) or technical success (OR 3, 95% CI 0.83-10.9). There were 9 complications, including 6 minor, 1 moderate, 1 severe, and 1 death. CONCLUSIONS: AngioVac aspiration thrombectomy of RAT is as safe and effective in patients with cancer as those without cancer.

Concomitant AngioVac thrombectomy and patent foramen ovale closure in a patient with a large right atrial thrombus and recent paradoxical embolic stroke.

A 59-year-old male with a history of gallbladder adenocarcinoma receiving chemotherapy and on therapeutic anticoagulation for portal vein thrombosis presented to the emergency department via ambulance after being found unresponsive and in cardiac arrest. Initial workup upon return of spontaneous circulation revealed a large right atrial mass, patent foramen ovale (PFO), and bilateral acute cortical infarctions. This constellation of findings were concerning for PFO-related paradoxical embolic strokes. Given the risk of recurrent paradoxical embolic events and the absolute contraindication to thrombolysis due to recent cerebral infarction, the decision was made to proceed with percutaneous vacuum-assisted thrombectomy using the AngioVac device. To prevent intraoperative thrombus propagation, PFO-closure was performed immediately prior to thrombectomy. Aspiration thrombectomy and PFO-closure were successful with complete thrombus removal and no intraoperative thrombus propagation. This case presents a minimally invasive and rapid treatment for a complex problem. An efficient and effective interdisciplinary team-based approach allowed the patient to resume cancer treatment relatively unabated.

Feasibility and Impact of a Student-Led, Semi-Structured, Near-Peer Student Guides Program on Navigating Through Medical School.

BACKGROUND: Mentorship is critical to developing health professionals. Near-peer mentorship pairs senior mentors with junior peers to help navigate academic, professional, and social aspects of training. METHODS: In this convergent parallel mixed methods study, we assessed the feasibility, usability, professional and social impact, and barriers to implementation of a 16-week semi-structured, near-peer, student guides program involving 39 first year medical students (MS1s) and 41 fourth year medical students (MS4s). Student enrollment was quantified, guide-guidee meetings tracked, and > 2 meetings defined as feasible. Meeting topics, impact on student advising, and barriers to sustainability were contextualized qualitatively. RESULTS: Twenty-two percent of all MS4s and 46% of MS1s enrolled in the program; 67% of guides facilitated the requisite two meetings with their group, which was less than our predetermined feasibility criteria of 75%. Most guide-guidee interactions occurred in person (91%), but text messages (82%) and video/mobile messaging apps (78%) were also used. Ninety-two percent of guidees recommended the program, and 85% were satisfied with guidance received. Barriers included meeting coordination, infrequent meetings, and informal meeting structure. CONCLUSIONS: While the program was infeasible by predefined frequency criteria, participant satisfaction was high and academic, professional, and social benefits of near-peers were reported. In response, programmatic revisions now incorporate centralized support for meetings, e-mentorship, and guide training.

The development and implementation of a layperson trauma first responder course in La Paz, Bolivia: A pilot study.

BACKGROUND: Ninety percent of nearly five million annual global injury deaths occur in low- and middle-income countries (LMICs), where prehospital care systems are frequently rudimentary or nonexistent. The World Health Organization considers layperson first-responders as essential for emergency medical services in low-resource settings lacking more formalized systems. This study sought to develop and implement a layperson trauma first responder course (TFRC) in Bolivia. MATERIALS AND METHODS: In March and April 2013 nine sessions of the eight-hour TFRC were held in La Paz, Bolivia. The course charged a nominal fee, and was led by an American surgeon and medical student. The TFRC built upon existing models with local stakeholder input, and included both didactic and practical components. Participants completed a baseline survey, and pre and posttests. The primary outcome was test performance, with secondary outcomes including demographic sub-group test score analyses and exam question validation. Data were assessed using nonparametric and psychometric methods RESULTS: One hundred fifty-nine individuals met study inclusion criteria. Participant median age was 28 (IQR 24, 36), 49.1% were male, 59.1% worked in a medical field, most had secondary (35.2%) or university (56.0%) level educations, and 67.3% had prior first aid training. Median test scores improved after course completion (48% vs. 76%, p <0.001), along with skill confidence (4 vs. 4.5, p <0.001). Most questions had appropriate item difficulty indices, point bi-serial correlation coefficients, and positive Pretest Posttest Difference Indices. Cronbach alpha coefficients for pre and posttest scores were 0.72 and 0.78, respectively. CONCLUSIONS: This study presents data from the first offering of an original TFRC for laypeople in Bolivia. Increased participant knowledge and skill confidence after course completion, and acceptable overall psychometric test properties, indicate this model is valid and effective. Future aims include TFRC revision, and enrollment of more layperson first responders to increase population-level impacts.

Trauma system development in low- and middle-income countries: a review.

BACKGROUND: Trauma systems in resource-rich countries have decreased mortality for trauma patients through centralizing resources and standardizing treatment. Rapid industrialization and urbanization have increased the demand for formalized emergency medical services and trauma services (EMS and TS) in low- and middle-income countries (LMICs). This systematic review examines initiatives to develop EMS and TS systems in LMICs to inform the development of comprehensive prehospital care systems in resource-poor settings. MATERIALS AND METHODS: EMS and TS system development publications were identified using MEDLINE, PubMed, and Scopus databases. Articles addressing subspecialty skill sets, public policy, or physicians were excluded. Two independent reviewers assessed titles, abstracts, and full texts in a hierarchical manner. RESULTS: A total of 12 publications met inclusion criteria, and 10 unique LMIC EMS and TS programs were identified. Common initiatives included the integration of existing EMS and TS services and provision of standardized training and formalized certification processes for prehospital care providers, as well as the construction of a conceptual framework for system development through the public health model. CONCLUSIONS: There is no single model of EMS and TS systems, and successful programs are heterogeneous across regions. Successful EMS and TS systems share common characteristics. A predevelopment needs assessment is critical in identifying existing EMS and TS resources as a foundation for further development. Implementation requires coordination of preexisting resources with cost-effective initiatives that involve local stakeholders. High-impact priority areas are identified to focus improvements. Financial stresses and mismatching of resources in LMICs are common and are more commonly encountered when implementing a high-income model EMS and TS in an LMIC. Preimplementation and postimplementation evaluations can determine the efficacy of initiatives to strengthen EMS and TS systems.

Layperson trauma training in low- and middle-income countries: a review.

BACKGROUND: Prehospital trauma systems are rudimentary in many low- and middle-income countries (LMICs) and require laypersons to stabilize and transport injured patients. The World Health Organization recommends educating layperson first responders as an essential step in the development of Emergency Medical Services systems in LMICs. This systematic review examines trauma educational initiatives for layperson first responders in resource-poor settings. MATERIALS AND METHODS: Layperson first-responder training and education program publications were identified using PubMed MEDLINE and Scopus databases. Articles addressing physicians, professional Emergency Medical Services training, or epidemiologic descriptions were excluded. Publications were assessed by independent reviewers, and those included underwent thematic analysis. RESULTS: Thirteen publications met inclusion criteria. Four themes emerged regarding the development of layperson first-responder training programs: (1) An initial needs assessment of a region's existing trauma system of care and laypersons' baseline emergency care knowledge focuses subsequent educational interventions; (2) effective programs adapt to and leverage existing resources; (3) training methods should anticipate participants with low levels of education and literacy; and (4) postimplementation evaluation allows for curriculum improvement. Technology, such as online and remote learning platforms, can be used to operationalize each theme. CONCLUSIONS: Successful training programs for layperson first responders in LMICs identify and maximize existing resources are adaptable to learners with little formal education and are responsive to postimplementation evaluation. Educational platforms that leverage technology to deliver content may facilitate first-responder trauma education in underresourced areas. Themes identified can inform the development of trauma systems of care to decrease mortality and physiological severity scores in trauma patients in LMICs.