Modelling lower-limb peripheral arterial disease using clinically available datasets: impact of inflow boundary conditions on hemodynamic indices for restenosis prediction

BACKGROUND AND OBJECTIVES

The integration of hemodynamic markers as risk factors in restenosis prediction models for lower-limb peripheral arteries is hindered by fragmented clinical datasets. Computed tomography (CT) scans enable vessel geometry reconstruction and can be obtained at different times than the Doppler ultrasound (DUS) images, which provide information on blood flow velocity. Computational fluid dynamics (CFD) simulations allow the computation of near-wall hemodynamic indices, whose accuracy depends on the prescribed inlet boundary condition (BC), derived from the DUS images. This study aims to: (i) investigate the impact of different DUS-derived velocity waveforms on CFD results; (ii) test whether the same vessel areas, subjected to altered hemodynamics, can be detected independently of the applied inlet BC; (iii) suggest suitable DUS images to obtain reliable CFD results.

METHODS

CFD simulations were conducted on three patients treated with bypass surgery, using patient-specific DUS-derived inlet BCs recorded at either the same or different time points than the CT scan. The impact of the chosen inflow condition on bypass hemodynamics was assessed in terms of wall shear stress (WSS)-derived quantities. Patient-specific critical thresholds for the hemodynamic indices were applied to identify critical luminal areas and compare the results with a reference obtained with a DUS image acquired in close temporal proximity to the CT scan.

RESULTS

The main findings indicate that: (i) DUS-derived inlet velocity waveforms acquired at different time points than the CT scan led to statistically significantly different CFD results (p<0.001); (ii) the same luminal surface areas, exposed to low time-averaged WSS, could be identified independently of the applied inlet BCs; (iii) similar outcomes were observed for the other hemodynamic indices if the prescribed inlet velocity waveform had the same shape and comparable systolic acceleration time to the one recorded in close temporal proximity to the CT scan.

CONCLUSIONS

Despite a lack of standardised data collection for diseased lower-limb peripheral arteries, an accurate estimation of luminal areas subjected to altered near-wall hemodynamics is possible independently of the applied inlet BC. This holds if the applied inlet waveform shares some characteristics - derivable from the DUS report - as one matching the acquisition time of the CT scan.

Role of toll-like receptor 4 in skeletal muscle damage in chronic limb-threatening ischemia

Objective

Toll-like receptors (TLRs) are key pattern recognition receptors in the innate immune system. In particular, the TLR4-mediated immune response has been implicated in ischemia-induced tissue injury. Mounting evidence supports a detrimental role of the innate immune system in the pathophysiology of skeletal muscle damage in patients with chronic limb-threatening ischemia (CLTI), in whom patient-oriented functional outcomes are poor. The overall aim of this study was to investigate the potential role of TLR4 in skeletal muscle dysfunction and damage in CLTI.

Methods

The role of TLR4 in ischemic muscle was investigated by (1) studying TLR4 expression and distribution in human gastrocnemius muscle biopsies, (2) evaluating the functional consequences of TLR4 inhibition in myotubes derived from human muscle biopsies, and (3) assessing the therapeutic potential of modulating TLR4 signaling in ischemic muscle in a mouse hindlimb ischemia model.

Results

TLR4 was found to be expressed in human muscle biopsies, with significant upregulation in samples from patients with CLTI. In vitro studies using cultured human myotubes demonstrated upregulation of TLR4 in ischemia, with activation of the downstream signaling pathway. Inhibition of TLR4 before ischemia was associated with reduced ischemia-induced apoptosis. Upregulation of TLR4 also occurred in ischemia in vivo and TLR4 inhibition was associated with decreased inflammatory cell infiltration and diminished apoptosis in the ischemic limb.

Conclusions

TLR4 is upregulated and activated in ischemic skeletal muscle in patients with CLTI. Modulating TLR4 signaling in vitro and in vivo was associated with attenuation of ischemia-induced skeletal muscle damage. This strategy could be explored further for potential clinical application.

A systematic review of clinical and biomechanical engineering perspectives on the prediction of restenosis in coronary and peripheral arteries

Objective

Restenosis is a significant complication of revascularization treatments in coronary and peripheral arteries, sometimes necessitating repeated intervention. Establishing when restenosis will happen is extremely difficult due to the interplay of multiple variables and factors. Standard clinical and Doppler ultrasound scans surveillance follow-ups are the only tools clinicians can rely on to monitor intervention outcomes. However, implementing efficient surveillance programs is hindered by health care system limitations, patients' comorbidities, and compliance. Predictive models classifying patients according to their risk of developing restenosis over a specific period will allow the development of tailored surveillance, prevention programs, and efficient clinical workflows. This review aims to: (1) summarize the state-of-the-art in predictive models for restenosis in coronary and peripheral arteries; (2) compare their performance in terms of predictive power; and (3) provide an outlook for potentially improved predictive models.

Methods

We carried out a comprehensive literature review by accessing the PubMed/MEDLINE database according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search strategy consisted of a combination of keywords and included studies focusing on predictive models of restenosis published between January 1993 and April 2023. One author independently screened titles and abstracts and checked for eligibility. The rest of the authors independently confirmed and discussed in case of any disagreement. The search of published literature identified 22 studies providing two perspectives-clinical and biomechanical engineering-on restenosis and comprising distinct methodologies, predictors, and study designs. We compared predictive models' performance on discrimination and calibration aspects. We reported the performance of models simulating reocclusion progression, evaluated by comparison with clinical images.

Results

Clinical perspective studies consider only routinely collected patient information as restenosis predictors. Our review reveals that clinical models adopting traditional statistics (n = 14) exhibit only modest predictive power. The latter improves when machine learning algorithms (n = 4) are employed. The logistic regression models of the biomechanical engineering perspective (n = 2) show enhanced predictive power when hemodynamic descriptors linked to restenosis are fused with a limited set of clinical risk factors. Biomechanical engineering studies simulating restenosis progression (n = 2) are able to capture its evolution but are computationally expensive and lack risk scoring for individual patients at specific follow-ups.

Conclusions

Restenosis predictive models, based solely on routine clinical risk factors and using classical statistics, inadequately predict the occurrence of restenosis. Risk stratification models with increased predictive power can be potentially built by adopting machine learning techniques and incorporating critical information regarding vessel hemodynamics arising from biomechanical engineering analyses.

Histopathological analysis of vascular malformations

OBJECTIVE

To propose and develop a histopathological criteria to help diagnose vascular malformations.

METHODS

All patients who underwent surgical resection and had a confirmed histopathological diagnosis of vascular malformations from 01 March 2018-26 February 2020 were included. A criteria based on 10 parameters was developed to help diagnose vascular malformations. Discrepancies between clinical and histopathological diagnosis were evaluated.

RESULTS

A total of 18 cases were identified. There was a discrepancy between the clinical diagnosis and the initially reported histopathological diagnosis in 16 cases (88.9%). This was reduced to 7 (38.9%) and 6 cases (33.3%) with first and second time revised histopathological analysis using proposed criteria.

CONCLUSIONS

The discrepancy between clinical and histopathological diagnoses of vascular malformations has highlighted the requirement of an agreed criteria for histopathologists to help formulate their diagnosis. The proposed criteria may be used as a guide in addressing this and guide treatment and improve clinical practice.

Efficacy and safety of embolo-sclerotherapy of arteriovenous malformations with foam sodium tetradecyl sulphate

BACKGROUND

To evaluate the efficacy and safety of embolo-sclerotherapy (EST) particularly with foamed sclerotherapy in the treatment of arteriovenous malformations (AVMs).

METHODS

All patients with AVM who underwent interventional therapy i.e. EST from January 1^st, 2015 - December 31^st, 2019 were identified through a prospective database. Types of AVM were classified according to Schobinger's classification. The outcome measures assessed efficacy and complications. The former was divided into four groups: no response, mild response, moderate response, and complete response.. Complications were defined as any tissue or functional damage, distal embolization or tissue reaction. Continuous variables were compared using analysis of variance (ANOVA) F test and discrete variables were analysed using χ² tests. P<0.05 was considered significant.

RESULTS

A total of 65 patients were included. There was no statistical difference amongst the volume of foam STS 3% or alcohol used across all types of AVM. Overall, majority of patients (86.2%) reported some degree of improvement following interventional therapy. Six (9.2%) patients experienced complications including necrosis and amputation. The proportions of complication were significantly different across the categories (P=0.009). Patients with type III AVM seemed to report more complications than others.

CONCLUSIONS

Foam sclerotherapy was clinically effective and safe for patients with AVM. This study showed that foam sclerotherapy with STS 3% provided a safe and efficacious alternative sclerosant to ethanol despite it was not often reported to be used to treat AVM. However, a combination of embolic agents is likely required to treat type IV AVMs.

Efficacy and safety of foam sclerotherapy with sodium tetradecyl sulfate as preferred sclerosant of venous malformations based on experience from a single specialist center

OBJECTIVE

We have assessed the efficacy and safety of interventional therapy for venous malformations (VMs), with foam sclerotherapy as the treatment of choice according to our experience at a single specialist center.

METHODS

All the patients with VMs who had undergone interventional therapy (ie, embolo-sclerotherapy and/or open surgery) from January 1, 2015 to December 31, 2019 were identified through a prospective database. The VM types were classified according to the Puig classification. The outcome measures assessed included the efficacy and complications. The former was divided into four groups: no response, mild response, moderate response, and complete response. The complications were defined as any tissue or functional damage, distal embolization, or tissue reaction. The continuous variables were compared using the analysis of variance F test, and discrete variables were analyzed using the χ² tests. P values < .05 were considered statistically significant.

RESULTS

A total of 207 patients were included. Puig type I lesions were significantly less likely to have received foam sclerotherapy using sodium tetradecyl sulfate (STS) 3% (P ≤ .001) and more likely to have been surgically excised (P ≤ .001). At the patient's first procedure during the study period, the volumes of foam STS 3% were significantly different across all types of VM (P ≤ .001). The patients with type I VMs had received a lower volume of STS 3% compared with those with type II and III VMs. The efficacy outcome categories were significantly different across all types of VMs (P ≤ .001). Overall, only 14 patients (6.8%) had reported no improvement in efficacy, and 38 patients (18%) had not attended follow-up. Therefore, 154 patients (74.8%) had experienced some form of efficacious outcome. Ten patients (4.8%) had developed complications such as hematoma, thrombophlebitis, and ulceration. The incidence of complications differed significantly across the categories (P = .030), with more complications reported for those with type I VMs.

CONCLUSIONS

We found that intervention with foam sclerotherapy using STS 3% is clinically effective and safe for patients with VMs and was most successful for those with Puig type I and II VMs.

Early follow-up quality of life and mental health of patients with congenital vascular malformations cared for in a multi-disciplinary specialist centre

OBJECTIVE

The study aimed to evaluate the early follow-up quality of life (QoL), pain and mental health of patients with congenital vascular malformation (CVM) from a variety of treatment options.

METHODS

All patients with CVM who received care and had follow-up between February 1st 2018 and January 31st 2020 were included. The health-related QoL, pain, and mental health were assessed with RAND Health Care 36-Item Short Form Survey (SF-36), visual analogue score for pain (VAS-P) and Hospital Anxiety and Depression Scale (HADS). Paired t-test was used for all analyses. p < .05 were considered significant.

RESULTS

In total, 110 patients with a mean age of 36.9 years were included in this study. In all patients following care, significant improvement was found in the bodily pain domain of SF-36 and VAS-P (both p = .01). This was largely driven by high-flow vascular malformation patients who responded better to embolo-sclerotherapy, which revealed significant improvement in the bodily pain domain of SF-36 (p = .002) and VAS-P (p = .02). Patients who received supportive treatment only reported significant improvement in mental health (p = .004) and social functioning (p = .03) domains of SF-36. Meanwhile, patients treated with embolo-sclerotherapy reported significant improvement only in VAS-P (p = .02).

CONCLUSIONS

This study concluded that the effects of care on early follow-up QoL, pain and mental health of patients with CVM were heterogenous. Future research should therefore, include larger sample size and longer term follow-up to understand the various factors that affect the QoL and mental health of these patients, as well as the holistic approaches to manage them.

ASAP─Automated Sonication-Free Acid-Assisted Proteomes─from Cells and FFPE Tissues

Formalin-fixed, paraffin-embedded (FFPE) tissues are an invaluable resource for retrospective studies, but protein extraction and subsequent sample processing steps have been shown to be challenging for mass spectrometry (MS) analysis. Streamlined high-throughput sample preparation workflows are essential for efficient peptide extraction from complex clinical specimens such as fresh frozen tissues or FFPE. Overall, proteome analysis has gained significant improvements in the instrumentation, acquisition methods, sample preparation workflows, and analysis pipelines, yet even the most recent FFPE workflows remain complex and are not readily scalable. Here, we present an optimized workflow for automated sonication-free acid-assisted proteome (ASAP) extraction from FFPE sections. ASAP enables efficient protein extraction from FFPE specimens, achieving similar proteome coverage as established methods using expensive sonicators, resulting in reduced sample processing time. The broad applicability of ASAP on archived pediatric tumor FFPE specimens resulted in high-quality data with increased proteome coverage and quantitative reproducibility. Our study demonstrates the practicality and superiority of the ASAP workflow as a streamlined, time- and cost-effective pipeline for high-throughput FFPE proteomics of clinical specimens.

The importance of inflammation control for the treatment of chronic diabetic wounds

Diabetic chronic wounds cause massive levels of patient suffering and economic problems worldwide. The state of chronic inflammation arises in response to a complex combination of diabetes mellitus-related pathophysiologies. Advanced treatment options are available; however, many wounds still fail to heal, exacerbating morbidity and mortality. This review describes the chronic inflammation pathophysiologies in diabetic ulcers and treatment options that may help address this dysfunction either directly or indirectly. We suggest that treatments to reduce inflammation within these complex wounds may help trigger healing.

The trend of percutaneous and open surgical procedures for peripheral arteriovenous malformations in the National Health Service England

INTRODUCTION

This study aimed to assess the trend of percutaneous and open surgical procedures for peripheral arteriovenous malformations (AVMs) performed in NHS hospitals in England between 2012 and 2018.

METHODS

Hospital Episode Statistics (HES) is a freely available data warehouse that represents the whole population of England served by the NHS. Data from the HES database was obtained and analysed for all hospital episodes between 2012 and 2018 for the total number and trend of 'primary diagnosis', and 'primary procedures and interventions' identified for peripheral AVMs.

RESULTS

Over the period studied, there was an increase in the total number of admissions for peripheral AVMs; total primary diagnosis increased from 2242 to 2857 per year. Open surgery remained more commonly performed than percutaneous procedures throughout the studied period. However, the overall percentage of primary procedures and interventions being percutaneous in this period increased from 29.8% to 41.0% per year. The increase in the number of percutaneous procedures per year seemed to occur in both children (from 43 to 124) and adults (from 408 to 492) over the course of the study period.

CONCLUSIONS

This study concluded that open surgery remained the most commonly performed primary procedure for peripheral AVMs, although there was an increasing trend for percutaneous procedures in NHS hospitals in England. The increase in the number and percentage of percutaneous procedures for peripheral AVMs was likely to have significant resource implications for the provision of care for patients with peripheral AVMs in NHS hospitals.

Multi-omic profiling of the leukemic microenvironment shows bone marrow interstitial fluid is distinct from peripheral blood plasma

Background

The bone marrow is the place of hematopoiesis with a microenvironment that supports lifelong maintenance of stem cells and high proliferation. It is not surprising that this environment is also favourable for malignant cells emerging in the bone marrow or metastasizing to it. While the cellular composition of the bone marrow microenvironment has been extensively studied, the extracellular matrix and interstitial fluid components have received little attention. Since the sinusoids connect the bone marrow interstitial fluid to the circulation, it is often considered to have the same composition as peripheral blood plasma. Stark differences in the cellular composition of the bone marrow and peripheral blood with different secretory capacities would however suggest profound differences.

Methods

In this study we set out to better define if and how the bone marrow interstitial fluid (BMIF) compares to the peripheral blood plasma (PBP) and how both are remodeled during chemotherapy. We applied a multi-omic strategy to quantify the metabolite, lipid and protein components as well as the proteolytic modification of proteins to gain a comprehensive understanding of the two compartments.

Results

We found that the bone marrow interstitial fluid is clearly distinct from peripheral blood plasma, both during active pediatric acute lymphoblastic leukemia and following induction chemotherapy. Either compartment was shaped differently by active leukemia, with the bone marrow interstitial fluid being rich in extracellular vesicle components and showing protease dysregulation while the peripheral blood plasma showed elevation of immune regulatory proteins. Following chemotherapy, the BMIF showed signs of cellular remodeling and impaired innate immune activation while the peripheral blood plasma was characterized by restored lipid homeostasis.

Conclusion

This study provides a comprehensive examination of the fluid portion of the acute lymphoblastic leukemia microenvironment and finds the contribution of either microenvironment to tumourigenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40164-022-00310-0.

The Impact of Same Gender Speed-Mentoring on Women's Perceptions of a Career in Surgery - A Prospective Cohort Study

BACKGROUND

Mentoring is critically important for the personal and professional development of a surgeon. Early career stage mentoring by same-gender role models may help ameliorate the gender imbalance in surgery based on our understanding of barriers for women pursuing surgical careers. A novel method of establishing these relationships is speed mentoring. This study aims to examine the impact of a one-day speed-mentoring session with same gender mentors on a cohort's perceptions of a career in surgery.

DESIGN

This prospective pre-post study compared attitudes and perceptions of a career in surgery before and after a speed-mentoring session with female surgeons. Mentees were assigned into groups of 1 or 2 and were paired with a female surgeon for 8 minutes. Each mentee group then rotated to another mentor for the same amount of time and this process continued for a total of twelve sessions. Mentees completed a 19-point questionnaire before and after the speed mentoring intervention.

SETTING

This multicenter study included participants from across the United Kingdom.

PARTICIPANTS

Inclusion criteria were female gender and medical student or foundation year doctor (internship year 1 or 2) status. Three hundred and forty participants participated in the intervention, 191 were included in the analysis.

RESULTS

Following intervention, the percentage of participants who agreed that having a family would negatively impact a woman's surgical career progression significantly decreased from 46.6% to 23.0%. The percentage of participants who agreed that an "old boys' club" attitude exists in surgery also significantly decreased (73.8%-58.1%). The percentage of participants who agreed it was more difficult for a woman to succeed in her surgical career than a man significantly decreased (73.8%-64.9%). One hundred and eighty-three (96%) participants agreed that mentorship is important for career progression and 153 (71.2%) participants stated that they did not have someone who they considered a mentor.

CONCLUSIONS

Conducting a speed mentoring program with same-gender role models significantly changed female medical students' and junior doctors' perceptions of women in surgery. The results suggest that such programs may be effective tools for facilitating mentor-mentee relationships and could be employed by surgical organizations to encourage a diverse uptake into surgery.

522 Early Follow-Up Quality of Life and Mental Health of Patients with Congenital Vascular Malformations Cared for in a Multi-Disciplinary Specialist Center

Aim

To evaluate the early follow-up quality of life (QoL), pain and mental health of patients with congenital vascular malformation (CVM) receiving care by a single multi-disciplinary specialist center

Method

This was a prospective observational study. All patients with CVM who received care (supportive treatment only, open surgery, targeted pharmacological therapy, embolosclerotherapy), and had follow-up, between February 1st 2018 and January 31st 2020 were included. The health-related QoL, pain, and mental health were assessed with validated questionnaires: SF-36, VAS-P and HADS. The CVM were categorized into types – low-flow (LFVM) and high-flow (HFVM), and anatomical locations. Paired t-test was used for all analyses. P&lt;0.05 were considered significant.

Results

110 patients (85 LFVM and 25 HFVM) with a mean age of 36.9 years were included. Significant improvement was found in the bodily pain domain of SF-36 and VAS-P (both P = 0.01) in all patients. However, only patients with HFVM reported significant improvement in the bodily pain domain of SF-36 (P=0.002) and VAS-P (P = 0.02). Patients who received supportive treatment only reported significant improvement in mental health (P=0.004) and social functioning (P=0.03) domains of SF-36. Meanwhile, patients treated with embolo-sclerotherapy reported significant improvement only in VAS-P (P=0.02). Patients who received targeted pharmacological therapy reported no significant early changes.

Conclusions

The effects of care on early follow-up QoL, pain and mental health of patients with CVM were heterogenous. Future research is required to understand the various factors that affect the QoL and mental health of these patients, as well as the holistic approaches to manage them.

O064 Early follow-up quality of life and mental health of patients with congenital vascular malformations cared for in a multi-disciplinary specialist center

Introduction

To evaluate the early follow-up quality of life (QoL), pain and mental health of patients with congenital vascular malformation (CVM) receiving care by a single multi-disciplinary specialist centre

Methods

All patients with CVM who received care (supportive treatment only, open surgery, targeted pharmacological therapy, embolosclerotherapy), and had follow-up, between 1 February 2018 and 31 January 2020 were included. The health-related QoL, pain, and mental health were assessed with validated questionnaires: SF-36, VAS-P and HADS. The CVM were categorized into types – low-flow (LFVM) and high-flow (HFVM), and anatomical locations. Paired t-test was used for all analyses. Differences were considered significant at P&lt;0.05.

Results

110 patients (85 LFVM and 25 HFVM) with a mean age of 36.9 years were included. Significant improvement was found in the bodily pain domain of SF-36 and VAS-P (both P = 0.01) in all patients. However, only patients with HFVM reported significant improvement in the bodily pain domain of SF-36 (P=0.002) and VAS-P (P = 0.02). Patients who received supportive treatment only reported significant improvement in mental health (P=0.004) and social functioning (P=0.03) domains of SF-36. Meanwhile, patients treated with embolosclerotherapy reported significant improvement only in VAS-P (P=0.02). Patients who received targeted pharmacological therapy reported no significant early changes.

Conclusion

The effects of care on early follow-up QoL, pain and mental health of patients with CVM were heterogenous. Future research is required to understand the various factors that affect the QoL and mental health of these patients, as well as the holistic approaches to manage them.

Take-home message

The effects of care on early follow-up QoL, pain and mental health of patients with CVM were heterogenous. Future research is required to understand the various factors that affect the QoL and mental health of these patients, as well as the holistic approaches to manage them.

A patient-specific multi-modality abdominal aortic aneurysm imaging phantom

Purpose

Multimodality imaging of the vascular system is a rapidly growing area of innovation and research, which is increasing with awareness of the dangers of ionizing radiation. Phantom models that are applicable across multiple imaging modalities facilitate testing and comparisons in pre-clinical studies of new devices. Additionally, phantom models are of benefit to surgical trainees for gaining experience with new techniques. We propose a temperature-stable, high-fidelity method for creating complex abdominal aortic aneurysm phantoms that are compatible with both radiation-based, and ultrasound-based imaging modalities, using low cost materials.

Methods

Volumetric CT data of an abdominal aortic aneurysm were acquired. Regions of interest were segmented to form a model compatible with 3D printing. The novel phantom fabrication method comprised a hybrid approach of using 3D printing of water-soluble materials to create wall-less, patient-derived vascular structures embedded within tailored tissue-mimicking materials to create realistic surrounding tissues. A non-soluble 3-D printed spine was included to provide a radiological landmark.

Results

The phantom was found to provide realistic appearances with intravascular ultrasound, computed tomography and transcutaneous ultrasound. Furthermore, the utility of this phantom as a training model was demonstrated during a simulated endovascular aneurysm repair procedure with image fusion.

Conclusion

With the hybrid fabrication method demonstrated here, complex multimodality imaging patient-derived vascular phantoms can be successfully fabricated. These have potential roles in the benchtop development of emerging imaging technologies, refinement of novel minimally invasive surgical techniques and as clinical training tools.

A Computational Framework for Pre-Interventional Planning of Peripheral Arteriovenous Malformations

PURPOSE

Peripheral arteriovenous malformations (pAVMs) are congenital lesions characterised by abnormal high-flow, low-resistance vascular connections-the so-called nidus-between arteries and veins. The mainstay treatment typically involves the embolisation of the nidus, however the complexity of pAVMs often leads to uncertain outcomes. This study aims at developing a simple, yet effective computational framework to aid the clinical decision making around the treatment of pAVMs using routinely acquired clinical data.

METHODS

A computational model was developed to simulate the pre-, intra-, and post-intervention haemodynamics of a patient-specific pAVM. A porous medium of varying permeability was employed to simulate the sclerosant effect on the nidus haemodynamics. Results were compared against clinical data (digital subtraction angiography, DSA, images) and experimental flow-visualization results in a 3D-printed phantom of the same pAVM.

RESULTS

The computational model allowed the simulation of the pAVM haemodynamics and the sclerotherapy-induced changes at different interventional stages. The predicted inlet flow rates closely matched the DSA-derived data, although the post-intervention one was overestimated, probably due to vascular system adaptations not accounted for numerically. The nidus embolization was successfully captured by varying the nidus permeability and increasing its hydraulic resistance from 0.330 to 3970 mmHg s ml-1. The nidus flow rate decreased from 71% of the inlet flow rate pre-intervention to 1%: the flow completely bypassed the nidus post-intervention confirming the success of the procedure.

CONCLUSION

The study demonstrates that the haemodynamic effects of the embolisation procedure can be simulated from routinely acquired clinical data via a porous medium with varying permeability as evidenced by the good qualitative agreement between numerical predictions and both in vivo and in vitro data. It provides a fundamental building block towards a computational treatment-planning framework for AVM embolisation.

HUNTER: Sensitive Automated Characterization of Proteolytic Systems by N Termini Enrichment from Microscale Specimen

Proteolysis occurs at low frequency in the cellular environment. Protein N termini reveal essential mechanisms associated with cellular functions, and are useful indicators to track dysfunctional regulation of proteins and pathways in diseases. N terminomics has so far relied on labor-intensive methods, which require relatively large starting sample amounts rendering it ill-suited for high-throughput systems biology studies. Here, we describe protocols for the first scalable and automatable method for sensitive enrichment and identification of N termini from minute samples.

Current pharmacotherapy management of children and adults with pericarditis: Prospectus for improved outcomes

Pericarditis is the most common inflammatory pericardial disease in both children and adults. Since the 2015 European Society of Cardiology Guidelines for the diagnosis and management of pericardial disease were published, there have been significant updates to management. Pharmacotherapy has been historically reserved for idiopathic pericarditis (IP). However, there has been increasing use of pharmacotherapies, such as anti-inflammatory therapies, colchicine, and immunotherapies for other causes of pericarditis, such as post-cardiac injury syndromes (PCIS). Nevertheless, the quality of data varies depending on PCIS or idiopathic etiologies, as well as the adult and pediatric population. High-dose anti-inflammatory therapies should be used to manage symptoms associated with either etiology of pericarditis in both adults and children, but do not ameliorate the inflammatory disease process. Choice of anti-inflammatory should be guided by drug-drug/disease interactions, cost, tolerability, patient age, and should be tapered accordingly over several weeks to months. Colchicine should be added as adjuvant therapy to anti-inflammatory therapies in adults and children with IP, as it has been shown to lower the risk of recurrence, reduce pericarditis symptoms, and improve morbidity. Colchicine is also reasonable to add to adults and children with pericarditis secondary to PCIS. Systemic glucocorticoids increase risk of recurrence in adults and children with IP and are reserved for second-line treatment in acute and recurrent IP; they are generally avoided in PCIS. Immunotherapies are regarded as third-line for recurrent IP in adults and children. Limited evidence exists to support their use in patients with pericarditis from PCIS. Pharmacovigilance strategies, such as C-reactive protein and adverse drug event monitoring, are also important toward balancing efficacy and safety of the various strategies used to manage pericarditis in adults and children.

Abstract P168: Promising Diagnostic Biomarkers For Congenital Vascular Malformations

Background: Congenital vascular malformations (CVMs) are vascular lesions that result from developmental errors during embryogenesis. They can occur anywhere in the body, causing pain, bleeding, ulcers, disfiguration, organ failure or limb loss. Depending on intralesional blood flow dynamics, CVMs can be broadly classified into low-flow (LF), which involve veins, lymphatics, capillaries or a mixture, and high-flow (HF), which involve arteries and veins. Accurate diagnosis and monitoring of LF and HF CVMs remains challenging and requires a wide range of imaging modalities.

Aim: We sought to identify potential diagnostic serum biomarkers, particularly those pertaining to the processes of inflammation and angiogenesis.

Methods: Sera were isolated from the peripheral bloods of consented healthy controls ( n = 10) and patients diagnosed as having either LF ( n = 10) or HF ( n = 10) CVMs. Various mediators of inflammation and angiogenesis were analysed in the sera using the Inflammation 20-Plex and Angiogenesis 18-Plex Human ProcartaPlex™ Panels. The levels of these mediators in patients with LF or HF CVMs were compared with those in healthy controls using the Kruskall-Wallis test and correlated with lesion volumes and visual analogue scores for pain using the Spearman rank correlation test.

Results: Compared to healthy controls, the inflammatory mediators E-selectin, IFNα, IFNγ, IL1β, IL4, IL12, IL17, MIP1α, MIP1β and TNFα were elevated in the sera of LF CVM patients, whereas only MIP1α was raised in the sera of HF CVM patients. None of the angiogenic mediators were altered in the sera of patients with LF or HF CVMs. Serum IFNα, IFNγ, IL4, IL12, TNFα, VEGFA, VEGFD and syndecan correlated positively with pain scores in patients with LF CVMs, whereas only IP10 did in patients with HF CVMs. Serum Ang1 and leptin correlated negatively with lesion volumes in patients with LF or HF CVMs, respectively.

Conclusion: Serum inflammatory mediators could be used as biomarkers to distinguish LF from HF CVMs and their expression seemed to be associated with pain severity in patients with LF CVMs. The angiogenic mediators Ang1 and leptin were associated with lesion volumes in patients with LF or HF CVMs, respectively.

O47 Safe delivery of surgical tracheostomies in COVID-19 patients during the pandemic

Introduction

During the corona virus disease (COVID-19) pandemic, frontline units worldwide faced the challenging task of providing high-risk services (like surgical tracheostomy) while safe-guarding the very people performing the high risk procedures. The aim of our study was to assess the incidence of COVID-19 infection among staff involved in surgical tracheostomy on COVID-19 patients

Method

A surgical tracheostomy protocol and operation theatre modifications were put in place at our centre, dictated by local resources, staff availability and previous tracheostomy experience. Between 26/03/2020 and 27/05/2020, staff participating in 71 tracheostomy procedures were sent a questionnaire. The presence of COVID-19 symptoms (new onset continuous cough, fever, loss of taste and/or loss of smell) in tracheostomy staff and patient related data were analysed.

Result

Among the responders (72/122), compliance with personal prophylaxis equipment use was 100%. Eleven (15%,11/72) reported key COVID-19 symptoms and self-isolated. 10 had a COVID-19 swab test and three tested positive. One staff attended (1/72) hospital for symptomatic treatment, none required hospitalisation. 43/72 staff (60%) underwent a COVID-19 antibody test, 18.6% (8/43) were positive. Among the tracheostomised patients, the mean age was 58 years(29–78) and 65.5% were males. The median time from intubation to ST was 15 days (range 5–33, IQR = 9). There were no tracheostomy related deaths and overall mortality was 11%(6/55).

Conclusion

Safe delivery of tracheostomy during a pandemic like COVID-19 is possible with strict adherence to personnel protective equipment, surgical protocols and regulation of traffic flow in theatres to mitigate the potential transmission of COVID-19 among surgical staff.

Take-home Message

Compliance with PPE, adherence to tracheostomy protocol and local modifications can mitigate potential COVID-19 transmission among health care personnel.

Incidence of major complications from embolo-sclerotherapy of head and neck vascular malformations in a single specialist centre

OBJECTIVE

Current data on the nature and rate of major complications for embolo-sclerotherapy (EST) of vascular malformations are scarce. However, even fewer studies focus on vascular malformations specific to the head and neck, which confer an increased specific risk of airway compromise, neurologic and ophthalmologic injury. More understanding is required surrounding the type and incidence of complications to improve treatment planning and informed consent. Therefore, this study aimed to review major complications secondary to EST of head and neck vascular malformations over a 5-year period in a single specialized multidisciplinary centre for vascular anomalies.

METHODS

All interventions were decided by the multidisciplinary team. Demographic, procedural and complication data between 1st January 2013 and 31st December 2017 were prospectively documented in a dedicated database and analysed. EST of high-flow vascular malformations (HFVMs) was performed by selective catheter angiography or direct injection, and by direct injection only for low-flow vascular malformations (LFVMs). Major complications were defined as any tissue or functional damage caused by direct injection, distal embolization or tissue reaction and were decided by the multidisciplinary team.

RESULTS

Forty-eight patients (median age of 35 years; range of 14-70 years; 18 men and 30 women) had 100 EST procedures for head and neck vascular malformation. Of these, 14 patients had EST for HFVM and 34 patients for LFVM, total 43 and 57 procedures, respectively. Overall, five patients with HFVM developed major complications from EST when compared with two patients with LFVM (p = 0.0167). Two patients required pre-emptive tracheostomy due to risk of post-operative airway compromise. Overall, seven (14.6%) patients experienced major complication from EST. In the HFVM group, major complications from EST occurred in five patients; four cases of tissue ulceration and necrosis (two needed debridement, one healed with resultant fibrosis that impeded speech and one resolved spontaneously) and one post-procedural airway compromise requiring tracheostomy. Meanwhile, in the LFVM group, major complications occurred in two patients; one case of severe necrosis involving the alar cartilage, lip and cheek requiring debridement and reconstruction under plastics and one simple cellulitis. No patients sustained stroke or vision impairment.

CONCLUSIONS

EST is relatively safe for head and neck vascular malformations in a high-volume experienced centre. Our major complication rate of 14.6% per patient (35.7% for HFVM; 5.9% for LFVM) or 7% per procedure (11.6% for HFVM; 3.5% LFVM) compares favourably with published data from other centres. These data will improve treatment planning and informed consent for EST for both HFVM and LFVM of the head and neck.

SARS-CoV-2 and Pre-existing Vascular Diseases: Guilt by Association?

Severe Acute Respiratory Syndrome coronavirus-2 has rapidly spread and emerged as a pandemic. Although evidence on its pathophysiology is growing, there are still issues that should be taken into consideration, including its effects on pre-existing peripheral vascular disease. The aim of this review is to describe the thrombotic and endothelial dysfunctions caused by SARS-CoV-2, assess if cardiovascular comorbidities render an individual susceptible to the infection and determine the course of pre-existing vascular diseases in infected individuals. A search through MEDLINE, PubMed and EMBASE was conducted and more than 260 articles were identified and 97 of them were reviewed; the rest were excluded because they were not related to the aim of this study. Hypertension, cardiovascular disease, diabetes mellitus and cerebrovascular diseases comprised 24.30% ± 16.23%, 13.29% ± 12.88%, 14.82% ± 7.57% and 10.82% ± 11.64% of the cohorts reviewed, respectively. Arterial and venous thrombotic complications rocketed up to 31% in severely infected individuals in some studies. We suggest that hypertension, cardiovascular diseases, diabetes and cerebrovascular diseases may render an individual susceptible to severe COVID-19 infection. Pre-existing vascular diseases are expected to deteriorate with SARS-CoV-2 infection as a consequence of its increased thrombotic burden and the development of endothelial dysfunction. COVID-19 has emerged only a few months ago and it is premature to predict the long-term effects to the vascular system. Its disturbances of the coagulation mechanisms and effects on vascular endothelium will likely provoke a surge of vascular complications in the coming months.

O75: SINGLE CENTRE EXPERIENCE OF SIROLIMUS THERAPY IN HEAD AND NECK VASCULAR MALFORMATIONS

Introduction

To assess the efficacy and safety of Sirolimus in the treatment of low-flow head and neck (H&N) vascular malformations

Method

Patients who presented to our tertiary referral clinic were assessed for eligibility. Suitable patients were commenced on Sirolimus at 0.8 mg/m2, administered orally twice daily, which was approved by our trust Drug and Therapeutic Committee. Patients were reviewed on a monthly basis for a total of six months with an additional one-month review to check for effects upon ceasing treatment. Efficacy and safety were measured through functional and radiological response, laboratory investigations and quality of life questionnaire (36-Item Short Form Health Survey (SF-36), Hospital Anxiety and Depression Scale (HADS) and Visual Analogue Score for Pain (VAS-P)).

Result

Seven patients (mean age 39 years, range 23-65 years) were recruited. One patient did not complete treatment due to intolerable side effects. All patients had a partial response with no patients showing disease progression or complete response. All post-treatment MRI scans showed stable disease with five patients demonstrating a decrease in lesion volume. Five patients reported return of symptoms at one-month post review upon discontinuation of treatment. No statistical significance (P&gt;0.05) in all eight domains of SF-36, HADS, VAS-P and radiological vascular lesion volume between pre- and post-treatment. Most common reported side effects were mouth ulcers (n=2) and metabolic/laboratory abnormality (n=2)

Conclusion

Sirolimus is an effective and safe treatment for patients with complicated low-flow H&N vascular malformations. This provides an alternative treatment where interventional therapy is considered to be limited or challenging.

Take-home message

Sirolimus is an effective and safe treatment option for patients with complicated low-flow head and neck vascular malformations where interventional therapy is limited or challenging.

Single Center Experience of Sirolimus Therapy in Head and Neck Low-flow Vascular Malformations

OBJECTIVE

Recently, studies have shown that sirolimus is clinically efficacious in the treatment of some low-flow vascular malformations (LFVM). This study aimed to assess the efficacy and safety of sirolimus in treating complex head and neck (H&N) LFVM that were challenging and/or refractory to standard treatment.

METHODS

Each patient had baseline and 6-months assessments consisting of clinical history and examination, quality of life (QoL) questionnaires, laboratory investigations, MRI and medical photography. Patients were followed up 1-week and then 1-monthly for 6-months. Wilcoxon signed-rank test was used to compare pre-and 6-months treatment in all 8 domains of RAND 36-Item Short Form Health Survey (SF-36), hospital anxiety and depression scale (HADS), and visual analog score for pain (VAS-P). P < 0.05 was considered significant.

RESULTS

Seven patients (median age 43 years, range 23-65 years) were recruited. Six patients completed the six-months course of therapy with 1 patient withdrawing due to intolerable side effects. All six patients reported reduction of swelling with and without other symptom improvement related to the vascular malformations while on treatment. However, at 1-month review after discontinuation of sirolimus, 5 patients reported return of initial symptoms. Overall, patients demonstrated an improvement in QoL six-months treatment but there was no statistical significance (P > 0.05) in all 8 domains of SF-36, HADS and VAS-P. Five patients demonstrated a minimum 10% decrease in lesion size six-months treatment (median 21%, range 13-40%). A Wilcoxon signed-rank test showed that sirolimus treatment did elicit a statistically significant change in lesion size in either direction (Z = -1.992, P = 0.046). The most common side effects found were dyslipidaemia (n-4) and mouth ulcers (n = 2).

CONCLUSION

In our preliminary experience, sirolimus is effective and safe in treating patients with complex H&N LFVM. This provides an alternative treatment where standard treatment is challenging and/or refractory.

Quality of life and mental health of patients with vascular malformations in a single specialist center in the United Kingdom

OBJECTIVE

Patients with vascular malformations suffer from chronic debilitating symptoms that have been shown to contribute negatively to their quality of life (QoL) and mental health. Despite this, the current literature evaluating the QoL and mental health of patients with vascular malformations remains scarce. Our aim was to evaluate the QoL and mental health of patients with vascular malformations.

METHODS

We prospectively analyzed the validated health-related QoL (HRQoL) questionnaires: the RAND Health Care 36-Item Short Form Survey (SF-36), Hospital Anxiety and Depression Scale (HADS), and visual analogue score for pain reported by 253 patients with vascular malformations in a specialist center of vascular anomalies in the UK over two years.

RESULTS

Patients with vascular malformations reported significantly poorer SF-36 scores in all domains compared with the UK general population. Patients with low-flow vascular malformations and arteriovenous malformations reported little variations in SF-36, HADS, and visual analogue score for pain scores. No significant association was found between age and any of the health-related QoL scores, other than the physical functioning in SF-36. Female patients reported significantly lower physical and social functioning of SF-36 and worse HADS-Depression than their male counterparts. Patients with syndromic vascular malformations reported significantly lower SF-36 scores in role-physical, role-emotional and bodily pain than nonsyndromic vascular malformations.

CONCLUSIONS

This study concluded that patients with vascular malformations reported worse QoL than the UK general population. Therefore, the assessment and management of QoL and mental health should be incorporated into the overall treatment strategies of patients with vascular malformations.

Computer assisted Doppler waveform analysis and ultrasound derived turbulence intensity ratios can predict early hyperplasia development in newly created vascular access fistula: Pilot study, methodology and analysis

Objectives

Following surgical creation of arterio-venous fistulae (AVF), the desired outward remodeling is often accompanied by the development of neointimal hyperplasia (NIH), which can stymie maturation and may lead to thrombosis and access failure. The aim of this study was to investigate the feasibility of using a non-invasive test, to detect and quantify the turbulent flow patterns believed to be associated with NIH development.

Design

This was a prospective, observational study. Ultrasound derived turbulence intensity ratios (USTIR) were calculated from spectral Doppler waveforms, recorded from newly formed AVF, and were compared with haemodynamic and structural changes observed during the initial maturation period.

Setting

Measurements were obtained by accredited Clinical Vascular Scientists, at the Royal Free Hospital, London.

Participants

Patients with newly created AVF were invited to participate in the study. A total of 30 patients were initially recruited with 19 participants completing the 10 week study protocol.

Outcome measures

The primary outcome measure was the development of NIH resulting in a haemodynamically significant lesion.The secondary outcome was successful maturation of the AVF at 10 weeks.

Results

Elevated USTIR in the efferent vein 2 weeks post surgery corresponded to the development of NIH formation (P = 0.02). A cut off of 6.39% predicted NIH development with a sensitivity of 87.5% and a specificity of 80%.

Conclusion

Analysis of Doppler waveforms can successfully identify deleterious flow patterns and predict inward luminal remodelling in maturing AVF. We propose a longitudinal follow up study to assess the viability of this technique as a surveillance tool.

130 Improving Documentation of Bowel Movement on Geriatric Wards

Introduction

Constipation is a widely prevalent issue in older adults that may result in complications such as urinary retention, delirium and bowel obstruction. Previous studies have indicated that while stool charts are well completed by nursing staff, they are infrequently monitored by doctors. This project aimed to improve the documentation of bowel movement by doctors on ward rounds to 85%, by the end of a 3-month period.

Methods

Formulation of the project was achieved using group work and a fishbone diagram which focussed on how doctors can improve on documenting bowel movements. Baseline data were collected from inpatient notes on weekdays over a three-week period on a geriatric ward in Northern General Hospital, Sheffield. Interventions of posters and stickers of the poo emoji were placed on walls and in inpatient notes respectively as a reminder. Post-intervention data were collected on weekdays over two weeks, and then repeated a month later to assess for a sustained change.

Results

The data on bowel activity documentation were collected from 28 patients. The baseline data showed that bowel activity was monitored daily on the ward 56.25% of the time. There was a significant increase in documentation of 85.75% following the interventions. The sustainability study showed that bowel activity was documented on the ward 59.09% of the time.

Conclusions

This study shows how a strong effect on behavioural change can be accomplished through simple interventions such as stickers and posters. As most wards currently still use paper notes, this is a generalisable model that other wards can trial. However, this study also shows the difficulty in maintaining behavioural change over extended periods of time. Further PDSA cycles should examine the reasons behind the difficulty sustaining the change and implement new changes that aim to overcome them.

PDX models reflect the proteome landscape of pediatric acute lymphoblastic leukemia but divert in select pathways

Background

Murine xenografts of pediatric leukemia accurately recapitulate genomic aberrations. How this translates to the functional capacity of cells remains unclear. Here, we studied global protein abundance, phosphorylation, and protein maturation by proteolytic processing in 11 pediatric B- and T- cell ALL patients and 19 corresponding xenografts.

Methods

Xenograft models were generated for each pediatric patient leukemia. Mass spectrometry-based methods were used to investigate global protein abundance, protein phosphorylation, and limited proteolysis in paired patient and xenografted pediatric acute B- and T- cell lymphocytic leukemia, as well as in pediatric leukemia cell lines. Targeted next-generation sequencing was utilized to examine genetic abnormalities in patients and in corresponding xenografts. Bioinformatic and statistical analysis were performed to identify functional mechanisms associated with proteins and protein post-translational modifications.

Results

Overall, we found xenograft proteomes to be most equivalent with their patient of origin. Protein level differences that stratified disease subtypes at diagnostic and relapse stages were largely recapitulated in xenografts. As expected, PDXs lacked multiple human leukocyte antigens and complement proteins. We found increased expression of cell cycle proteins indicating a high proliferative capacity of xenografted cells. Structural genomic changes and mutations were reflected at the protein level in patients. In contrast, the post-translational modification landscape was shaped by leukemia type and host and only to a limited degree by the patient of origin. Of 201 known pediatric oncogenic drivers and drug-targetable proteins, the KMT2 protein family showed consistently high variability between patient and corresponding xenografts. Comprehensive N terminomics revealed deregulated proteolytic processing in leukemic cells, in particular from caspase-driven cleavages found in patient cells.

Conclusion

Genomic and host factors shape protein and post-translational modification landscapes differently. This study highlights select areas of diverging biology while confirming murine patient-derived xenografts as a generally accurate model system.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01835-8.

Transmission of infection among health care personnel performing surgical tracheostomies on COVID-19 patients

Background

Staff and patient safety are of paramount importance while performing a surgical tracheostomy (ST) during the corona virus disease (COVID-19) pandemic. The aim was to assess the incidence of COVID-19 infection among the healthcare personnel (HCP) performing ST on COVID-19 patients.

Methods

One hundred and twenty-two HCP participating in 71 ST procedures performed at our institution between 26th March 2020 and 27th May 2020 were identified. A COVID-19 health questionnaire was distributed among staff with their consent. Data related to the presence of COVID-19 symptoms (new onset continuous cough, fever, loss of taste and/or loss of smell) among HCP involved in ST as well as patient related data were collected.

Results

Of the HCP who responded, eleven (15%,11/72) reported key COVID-19 symptoms and went into self-isolation. Ten members from this group underwent a COVID-19 swab test and three tested positive. Only one HCP attended hospital for symptomatic treatment, none required hospitalisation. Sixty percent (43/72) of the responders had a COVID-19 antibody test with a positive rate of 18.6% (8/43).

Among the patients undergoing a ST, 67% (37/55) required a direct intensive care unit (ICU) admission; the mean age was 58 years (29–78) with a male preponderance (65.5%). The median time from intubation to ST was 15 days (range 5–33,IQR = 9). The overall mortality was 11% (6/55).

Conclusions

ST can be carried out safely with strict adherence to both, personnel protective equipment and ST protocols which are vital to mitigate the potential transmission of COVID-19 to the HCP.

Patient radiation exposure from embolo-sclerotherapy of peripheral vascular malformations

OBJECTIVE

Embolo-sclerotherapy (EST) is the mainstay therapy for peripheral vascular malformations that involves the exposure of patients to ionizing radiation. We analyzed the radiation exposure to patients from EST of peripheral vascular malformations during a 5-year period in a single specialist center.

METHODS

All patients who had undergone EST at a single specialist center for peripheral vascular malformations from January 1, 2013 to January 8, 2018 were identified from a prospectively collected database. Data collection included basic demographics, procedure date, anatomic site, type of vascular malformations, and procedural details. Radiation exposure, measured as the dose-area product (DAP) and fluoroscopy time, of all patients who had undergone EST during the study period were retrospectively reviewed. Statistical analysis was performed using the Mann-Whitney U and Kruskal-Wallis tests for comparison between subgroups. P < .05 was considered statistically significant.

RESULTS

A total of 237 patients (median age, 30 years; range, 1-73 years) had undergone 419 EST sessions during the study period. Of the 237 patients, 61 (25.7%) had had arteriovenous malformations (AVMs) and had undergone 140 EST sessions (33.4%) and 176 (74.3%) had had venous and lymphatic malformations and had undergone 279 EST sessions (66.6%). Patients with AVMs had undergone a median of 2 procedures (range, 1-13) compared with a median of 1 (range, 1-6) for venous and lymphatic malformations within the study period. The median DAP for the single and cumulative EST for peripheral vascular malformations was 1.26 Gycm² (range, 0.00-698.36 Gycm²) and 1.91 Gycm² (range, 0.00-1300.24 Gycm²), respectively. The median fluoroscopy time for single and cumulative EST was 19 seconds (range, 1-3846 seconds) and 30 seconds (range, 1-5843 seconds), respectively. Significantly greater patient radiation exposure, in DAP and fluoroscopy time, was measured for single and cumulative EST for AVMs compared with venous and lymphatic malformations (P < .01 for both; Mann-Whitney U test). A significant difference in DAP but not fluoroscopy time was found when the anatomic areas of vascular malformations were compared.

CONCLUSIONS

Patient radiation exposure for EST for peripheral vascular malformations, measured in DAP and fluoroscopy time, appeared to be generally less than that reported for endovascular arterial and deep venous interventions. However, some patients with peripheral vascular malformations received relatively high radiation doses. Further studies to investigate the risk factors and long-term side effects of radiation exposure in these patients and strategies to reduce these are required.

Incidence of major complication following embolo-sclerotherapy for upper and lower extremity vascular malformations

OBJECTIVE

The current literature on the major complications of embolo-sclerotherapy of upper and lower extremity vascular malformations is scarce. Evaluating and understanding the rates and types of potential major complications of embolo-sclerotherapy of vascular malformations help treatment planning and informed consent. Therefore, this study reviewed major complications following embolo-sclerotherapy of all upper and lower extremity vascular malformations in a single specialized multidisciplinary vascular malformation center over a 5-year period.

METHODS

All patients with vascular malformations underwent multidisciplinary directed intervention. Demographic, procedural, follow-up, and complication data were collected prospectively in a dedicated database, and reviewed retrospectively. Major complications for upper and lower extremity vascular malformations from 1 January 2013 to 31 December 2017 were analyzed. All embolo-sclerotherapies of high-flow vascular malformations (HFVMs) were performed under selective catheter angiography and direct injection, but low-flow vascular malformations (LFVM) with direct injection only. Major complications were defined as any tissue or functional damage caused by direct injection, distal embolization, or tissue reaction.

RESULTS

Seventy patients (median age of 25 years; 44 males and 26 females) had 150 embolo-sclerotherapy procedures for upper extremity vascular malformation. Of these, 28 patients had embolo-sclerotherapy for HFVM and 42 patients for LFVM; total 78 and 72 procedures, respectively. A total of 107 patients (median age of 26 years; 42 males and 65 females) had 160 embolo-sclerotherapy interventions for lower extremity vascular malformations. Of these, 18 patients had embolo-sclerotherapy for HFVM and 89 patients for LFVM; total of 30 and 130 procedures, respectively. The overall major complication rates following embolo-sclerotherapy of upper and lower extremity vascular malformations were 14.3% and 4.7%, respectively (P = 0.030). In the upper extremity HFVM group, major complications from embolo-sclerotherapy occurred in five patients; three ischemic fingers requiring amputation and two skin ulcerations. Meanwhile, in the upper extremity LFVM group, major complications occurred in five patients; one median nerve injury requiring nerve grafting and hand therapy, one hand contracture requiring tendon release, and three skin ulcerations. There was only one major complication, which was cellulitis in the lower extremity HFVM group. In the lower extremity LFVM group, major complications occurred in four patients; two skin ulcerations, one cellulitis, and one deep vein thrombosis.

CONCLUSIONS

Embolo-sclerotherapy is relatively safe for upper and lower extremity vascular malformations in a high-volume experienced center where our major complication rates were 14.3% and 4.7%, respectively, which compare favorably or similar to those reported in most recent literature. These outcomes will direct treatment strategies to avoid local and systemic toxic complications in the upper and lower extremity, for both HFVM and LFVM, and to improve informed consent.

Emerging importance of molecular pathogenesis of vascular malformations in clinical practice and classifications

Vascular malformations occur during early vascular development resulting in abnormally formed vessels that can manifest as arterial, venous, capillary or lymphatic lesions, or in combination, and include local tissue overdevelopment. Vascular malformations are largely caused by sporadic somatic gene mutations. This article aims to review and discuss current molecular signaling pathways and therapeutic targets for vascular malformations and to classify vascular malformations according to the molecular pathways involved. A literature review was performed using Embase and Medline. Different MeSH terms were combined for the search strategy, with the aim of encompassing all studies describing the classification, pathogenesis, and treatment of vascular malformations. Major pathways involved in the pathogenesis of vascular malformations are vascular endothelial growth factor (VEGF), Ras/Raf/MEK/ERK, angiopoietin-TIE2, transforming growth factor beta (TGF-β), and PI3K/AKT/mTOR. These pathways are involved in controlling cellular growth, apoptosis, differentiation, and proliferation, and play a central role in endothelial cell signaling and angiogenesis. Many vascular malformations share similar aberrant molecular signaling pathways with cancers and inflammatory disorders. Therefore, selective anticancer agents and immunosuppressants may be beneficial in treating vascular malformations of specific mutations. The current classification systems of vascular malformations, including the International Society of the Study of Vascular Anomalies (ISSVA) classification, are primarily observational and clinical, and are not based on the molecular pathways involved in the pathogenesis of the condition. Several molecular pathways with potential therapeutic targets have been demonstrated to contribute to the development of various vascular anomalies. Classifying vascular malformations based on their molecular pathogenesis may improve treatment by determining the underlying nature of the condition and their potential therapeutic target.

AB1207 EFFECT ON DIET MODIFICATION ON GOUT AND METABOLIC SYNDROME RISK FACTORS

Background:

Gout is the most prevalent inflammatory arthritis globally. Despite treatment advances, the prevalence of gout has continued to increase over the last several decades. There has also been increasing evidence that gout has a strong association with the metabolic syndrome. This indicates that gout is likely both an inflammatory and a metabolic disease that has a significant effect on quality of life and healthcare costs. Although current recommendations support aggressive medical therapy for gout treatment, dietary counseling is less emphasized. We hypothesize that emphasis on this nonpharmacological therapy will likely improve management and the metabolic syndrome in gout patients.

Objectives:

To analyze the effectiveness of dietary counseling on gout management and risk factors for metabolic syndrome in gout patients at the Veteran’s Affairs Medical Center in Long Beach, CA (VALB).

Methods:

A retrospective cohort study was created from 2009-2016 involving Long Beach Veterans Affairs Hospital gout patients (n= 119) based on International Classification of Disease version 9 or 10. Patients were then stratified into two cohorts: received diet counseling (n=90) and no diet counseling (n=29). Data was reviewed for 24 months following initial gout diagnosis or intervention. Management was evaluated based on frequency of flares and related ED visits, change in creatinine clearance, serum uric acid levels (sUA), and changes to risk factors for metabolic syndrome including blood pressure, body mass index (BMI), cholesterol panel and hemoglobin A1c levels at six-month intervals.

Results:

Although patients in both cohorts were noted to have decreased number of gout attacks, patients who received diet counseling had a significant decrease in number of gout attacks by month 12 (0=0.004). In addition, after 6 months, patients who received diet counseling were more likely to have sUA at goal (sUA<6 for nontophaeous gout and sUA<5 for tophaceous gout) (p=0.003). These patients were also noted to have improved creatinine clearance (p=0.08) and increased HDL (p =0.08). In addition, patients with improved HDL and LDL values more likely to have improved sUA levels and decreased ED visits (R2=0.4, slope 0.14 and R2=0.4, slope 0.05, respectively) by month 6. Patients with improved hemoglobin A1c levels were also noted to have a significant outcome in lowering serum uric acid level at month 18 (R2=0.9, slope 2.6).

Conclusion:

Gout patients who receive diet counseling had lower rate of future attacks and better control of sUA. In addition, these gout patients were also noted to have improvement in some risk factors associated with the metabolic syndrome. Notably, patients who had better control of their hemoglobin A1c levels were able to have lower serum uric acid levels. This may imply that controlling diabetes in patients may also help improve gout management. Given the serious complications and increased cardiovascular risks that can be associated with metabolic syndrome, optimization of gout through a nonpharmacologic intervention such as diet counseling can enhance clinical outcomes and optimize healthcare resources.

References:

[1]Rai SK et al. The Dietary Approaches to Stop Hypertension (DASH) diet, Western diet, and risk of gout in men: prospective cohort study. BMJ. 2017;357:j1794.

[2]Álvarez-lario B, et al. Hyperuricemia and gout; the role of diet. Nutr Hosp. 2014;29(4):760-70.

Disclosure of Interests:

None declared

Endothelial C-Type Natriuretic Peptide Is a Critical Regulator of Angiogenesis and Vascular Remodeling

BACKGROUND

Angiogenesis and vascular remodeling are complementary, innate responses to ischemic cardiovascular events, including peripheral artery disease and myocardial infarction, which restore tissue blood supply and oxygenation; the endothelium plays a critical function in these intrinsic protective processes. C-type natriuretic peptide (CNP) is a fundamental endothelial signaling species that coordinates vascular homeostasis. Herein, we sought to delineate a central role for CNP in angiogenesis and vascular remodeling in response to ischemia.

METHODS

The in vitro angiogenic capacity of CNP was examined in pulmonary microvascular endothelial cells and aortic rings isolated from wild-type, endothelium-specific CNP^-/-, global natriuretic peptide receptor (NPR)-B^-/- and NPR-C^-/- animals, and human umbilical vein endothelial cells. These studies were complemented by in vivo investigation of neovascularization and vascular remodeling after ischemia or vessel injury, and CNP/NPR-C expression and localization in tissue from patients with peripheral artery disease.

RESULTS

Clinical vascular ischemia is associated with reduced levels of CNP and its cognate NPR-C. Moreover, genetic or pharmacological inhibition of CNP and NPR-C, but not NPR-B, reduces the angiogenic potential of pulmonary microvascular endothelial cells, human umbilical vein endothelial cells, and isolated vessels ex vivo. Angiogenesis and remodeling are impaired in vivo in endothelium-specific CNP^-/- and NPR-C^-/-, but not NPR-B^-/-, mice; the detrimental phenotype caused by genetic deletion of endothelial CNP, but not NPR-C, can be rescued by pharmacological administration of CNP. The proangiogenic effect of CNP/NPR-C is dependent on activation of G_i, ERK1/2, and phosphoinositide 3-kinase γ/Akt at a molecular level.

CONCLUSIONS

These data define a central (patho)physiological role for CNP in angiogenesis and vascular remodeling in response to ischemia and provide the rationale for pharmacological activation of NPR-C as an innovative approach to treating peripheral artery disease and ischemic cardiovascular disorders.

Sensitive Determination of Proteolytic Proteoforms in Limited Microscale Proteome Samples

Protein N termini unambiguously identify truncated, alternatively translated or modified proteoforms with distinct functions and reveal perturbations in disease. Selective enrichment of N-terminal peptides is necessary to achieve proteome-wide coverage for unbiased identification of site-specific regulatory proteolytic processing and protease substrates. However, many proteolytic processes are strictly confined in time and space and therefore can only be analyzed in minute samples that provide insufficient starting material for current enrichment protocols. Here we present High-efficiency Undecanal-based N Termini EnRichment (HUNTER), a robust, sensitive and scalable method for the analysis of previously inaccessible microscale samples. HUNTER achieved identification of >1000 N termini from as little as 2 μg raw HeLa cell lysate. Broad applicability is demonstrated by the first N-terminome analysis of sorted human primary immune cells and enriched mitochondrial fractions from pediatric cancer patients, as well as protease substrate identification from individual Arabidopsis thaliana wild type and Vacuolar Processing Enzyme-deficient mutant seedlings. We further implemented the workflow on a liquid handling system and demonstrate the feasibility of clinical degradomics by automated processing of liquid biopsies from pediatric cancer patients.

Polyhexamethylene Biguanide:Polyurethane Blend Nanofibrous Membranes for Wound Infection Control

Polyhexamethylene biguanide (PHMB) is a broad-spectrum antiseptic which avoids many efficacy and toxicity problems associated with antimicrobials, in particular, it has a low risk of loss of susceptibility due to acquired antimicrobial resistance. Despite such advantages, PHMB is not widely used in wound care, suggesting more research is required to take full advantage of PHMB’s properties. We hypothesised that a nanofibre morphology would provide a gradual release of PHMB, prolonging the antimicrobial effects within the therapeutic window. PHMB:polyurethane (PU) electrospun nanofibre membranes were prepared with increasing PHMB concentrations, and the effects on antimicrobial activities, mechanical properties and host cell toxicity were compared. Overall, PHMB:PU membranes displayed a burst release of PHMB during the first hour following PBS immersion (50.5–95.9% of total released), followed by a gradual release over 120 h (≤25 wt % PHMB). The membranes were hydrophilic (83.7–53.3°), gradually gaining hydrophobicity as PHMB was released. They displayed superior antimicrobial activity, which extended past the initial release period, retained PU hyperelasticity regardless of PHMB concentration (collective tensile modulus of 5–35% PHMB:PU membranes, 3.56 ± 0.97 MPa; ultimate strain, >200%) and displayed minimal human cell toxicity (<25 wt % PHMB). With further development, PHMB:PU electrospun membranes may provide improved wound dressings.

A paradigm shift in the provision of improved critical care in the emergency department

With Hong Kong's ageing population, advancement of medical technologies and hospital congestion, it is not uncommon for emergency physicians to encounter complicated critically ill patients in daily practice. It becomes a fundamental role of emergency physicians to initiate timely diagnostic and therapeutic interventions to save a patient's life and improve their prognosis. It is the reason a critical care service has been developed in emergency departments worldwide over the last decade. This article shares how emergency department intensivists can contribute to this novel model of care with some illustrative cases. Advanced airway and peri-intubation management, difficult mechanical ventilation, treatment of shock, circulatory arrest, and metabolic disturbances can be safely and efficiently handled in the current emergency department setting. Obstacles, barriers, and the road ahead will be discussed.

Abstract 130: Exosomal Cellular Communication in Peripheral Arterial Disease

Background: Exosomes are nano-meter sized vesicles that play a role in cellular communication. Their effects on target cells are influenced by their cellular source and associated niche. We hypothesize that exosomal communication is involved in the local and systemic pathology of peripheral arterial disease (PAD), where exosomes derived from ischaemic muscle contribute to impaired muscle regeneration and endothelial dysfunction. This study aims to investigate the effect of ischaemia on skeletal muscle exosomes and their potential role in PAD.

Methods: Exosomes were isolated from C2C12 myoblasts (MB), MTs and ischaemic MTs (IMTs) through ultracentrifugation. Comparative analysis of MT and IMT exosomes was performed using Nanosight, western blotting (WB) and electron microscopy (EM). PKH26 labelled MB, MT and IMT exosomes were co-cultured with myoblasts or human umbilical vein endothelial cells (HUVECs) for 6, 12 and 24hrs. Exosome uptake was assessed by fluorescent microscopy and FACs. The effect of IMT exosomes on myoblast differentiation was assessed by WB for myogenin and myosin heavy chain.

Results: Exosomes were secreted by MTs and IMTs at similar frequencies and were structurally similar. Both were positive for exosomal markers CD81 and Alix. Following 24hr co-culture of PKH26 labelled exosomes with myoblasts or HUVECs, over 80% (over 4000 of 5000) of cells fluoresced positively, signifying internalisation of the exosomes by myoblasts and HUVECs. IMT but not MT derived exosomes impaired myoblast differentiation.

Conclusion: MT derived exosomes are taken up by both myoblasts and endothelial cells. Whilst ischaemia does not significantly alter MT derived exosomes quantitatively or structurally, internalisation of IMT exosomes impairs differentiation of myoblasts to myotubes. This suggests that in PAD, altered exosomal message secondary to ischaemia, contributes to muscle dysfunction. Our data also indicates that there is muscle-endothelial cell cross-talk via exosomes, which may also contribute to systemic cardiovascular morbidity. Clarification of the functional effects and delineation of the mechanisms involved may lead to new targets that can be manipulated to improve outcomes of patients with PAD.

Current Treatment Strategies for Intracranial Aneurysms: An Overview

Intracranial aneurysm is a leading cause of stroke. Its treatment has evolved over the past 2 decades. This review summarizes the treatment strategies for intracranial aneurysms from 3 different perspectives: open surgery approach, transluminal treatment approach, and new technologies being used or trialed. We introduce most of the available treatment techniques in detail, including contralateral clipping, wrapping and clipping, double catheters assisting coiling and waffle-cone technique, and so on. Data from major trials such as Analysis of Treatment by Endovascular approach of Non-ruptured Aneurysms (ATENA), Internal Subarachnoid Trial (ISAT), Clinical and Anatomical Results in the Treatment of Ruptured Intracranial Aneurysms (CLARITY), and Barrow Ruptured Aneurysm Trial (BRAT) as well as information from other clinical reports and local experience are reviewed to suggest a clinical pathway for treating different types of intracranial aneurysms. It will be a valuable supplement to the current existing guidelines. We hope it could help assisting real-time decision-making in clinical practices and also encourage advancements in managing the disease.

Future research directions to improve fistula maturation and reduce access failure

With the increasing prevalence of end-stage renal disease, there is a growing need for hemodialysis. Arteriovenous fistulae (AVF) are the preferred type of vascular access for hemodialysis, but maturation and failure continue to present significant barriers to successful fistula use. AVF maturation integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes in the setting of uremia, systemic inflammation, oxidative stress, and pre-existent vascular pathology. AVF can fail due to both failure to mature adequately to support hemodialysis and development of neointimal hyperplasia that narrows the AVF lumen, typically near the fistula anastomosis. Failure due to neointimal hyperplasia involves vascular cell activation and migration and extracellular matrix remodeling with complex interactions of growth factors, adhesion molecules, inflammatory mediators, and chemokines, all of which result in maladaptive remodeling. Different strategies have been proposed to prevent and treat AVF failure based on current understanding of the modes and pathology of access failure; these approaches range from appropriate patient selection and use of alternative surgical strategies for fistula creation, to the use of novel interventional techniques or drugs to treat failing fistulae. Effective treatments to prevent or treat AVF failure require a multidisciplinary approach involving nephrologists, vascular surgeons, and interventional radiologists, careful patient selection, and the use of tailored systemic or localized interventions to improve patient-specific outcomes. This review provides contemporary information on the underlying mechanisms of AVF maturation and failure and discusses the broad spectrum of options that can be tailored for specific therapy.

The innate immune system, toll-like receptors and dermal wound healing: A review

Wound healing is a complex physiological process comprised of discrete but inter-related and overlapping stages, requiring exact timing and regulation to successfully progress, yet occurs spontaneously in response to injury. It is characterised by four phases, coagulation, inflammation, proliferation and remodelling. Each phase is predominated by particular cell types, cytokines and chemokines. The innate immune system represents the first line of defence against invading microorganisms. It is entirely encoded with the genome, and comprised of a cellular response with specificity provided by pattern recognition receptors (PRRs) such as toll-like receptors (TLRs). TLRs are activated by exogenous microbial pathogen associated molecular patterns (PAMPs), initiating an immune response through the production of pro-inflammatory cytokines and further specialist immune cell recruitment. TLRs are also activated by endogenous molecular patterns termed damage associated molecular patterns (DAMPs). These ligands, usually shielded from the immune system, act as alarm signals alerting the immune system to damage and facilitate the normal wound healing process. TLRs are expressed by cells essential to wound healing such as keratinocytes and fibroblasts, however the specific role of TLRs in this process remains controversial. This article reviews the current knowledge on the potential role of TLRs in dermal wound healing where inflammation arising from pathogenic activation of these receptors appears to play a role in chronic ulceration associated with diabetes, scar hypertrophy and skin fibrosis.