Human atherosclerotic plaque transcriptomics reveals endothelial beta-2 spectrin as a potential regulator a leaky plaque microvasculature phenotype

The presence of atherosclerotic plaque vessels is a critical factor in plaque destabilization. This may be attributable to the leaky phenotype of these microvessels, although direct proof for this notion is lacking. In this study, we investigated molecular and cellular patterns of stable and hemorrhaged human plaque to identify novel drivers of intraplaque vessel dysfunction. From transcriptome data of a human atherosclerotic lesion cohort, we reconstructed a co-expression network, identifying a gene module strongly and selectively correlated with both plaque microvascular density and inflammation. Spectrin Beta Non-Erythrocytic 1 (sptbn1) was identified as one of the central hubs of this module (along with zeb1 and dock1) and was selected for further study based on its predominant endothelial expression. Silencing of sptbn1 enhanced leukocyte transmigration and vascular permeability in vitro, characterized by an increased number of focal adhesions and reduced junctional VE-cadherin. In vivo, sptbn1 knockdown in zebrafish impaired the development of the caudal vein plexus. Mechanistically, increased substrate stiffness was associated with sptbn1 downregulation in endothelial cells in vitro and in human vessels. Plaque SPTBN1 mRNA and protein expression were found to correlate with an enhanced presence of intraplaque hemorrhage and future cardiovascular disease (CVD) events during follow-up. In conclusion, we identify SPTBN1 as a central hub gene in a gene program correlating with plaque vascularisation. SPTBN1 was regulated by substrate stiffness in vitro while silencing blocked vascular development in vivo, and compromised barrier function in vitro. Together, SPTBN1 is identified as a new potential regulator of the leaky phenotype of atherosclerotic plaque microvessels.

Clinical Performance of the Low Profile Zenith Alpha Abdominal Endovascular Graft: 2 Year Results from the ZEPHYR Registry

OBJECTIVE

The midterm outcomes of the low profile Zenith Alpha Abdominal Endovascular Graft from the ZEnith alPHa for aneurYsm Repair (ZEPHYR) registry are reported.

METHODS

The ZEPHYR registry is a physician initiated, multicentre, non-randomised, core laboratory controlled, prospective registry. Inclusion criteria were patients with a non-ruptured abdominal aortic aneurysm with a maximum diameter ≥ 50 mm or enlargement > 5 mm within 6 months, with a site reported infrarenal neck length of ≥ 10 mm and with the intention to electively implant the Zenith Alpha abdominal endograft. Patients from 14 sites across Germany, Belgium, and the Netherlands were included. The primary endpoint was treatment success, defined as technical success and clinical success. Technical success was defined as successful delivery and deployment of the endograft in the planned position without unintentional coverage of internal iliac or renal arteries, with successful removal of the delivery system. Clinical success was defined as freedom from aneurysm sac expansion > 5 mm, type I or type III endoleaks, aneurysm rupture, stent graft migration > 10 mm, open conversion, and stent graft occlusion.

RESULTS

Three hundred and forty-seven patients were included in the ZEPHYR registry. The median clinical follow up was 743 days (interquartile range [IQR] 657, 806) with a median imaging follow up of 725 days (IQR 408, 788). Treatment success at 6 months, 1, and 2 years was 92.5%, 90.4%, and 85.3%, respectively. Freedom from secondary intervention was 94.3%, 93.4%, and 86.9%, respectively. The predominant reason for secondary intervention was limb complications. Freedom from limb occlusion (per patient) at 6 months, 1, and 2 years was 97.2%, 95.8%, and 92.5%, respectively. Univariable and multivariable Cox regression analyses could not identify any independent predictor for limb complications.

CONCLUSION

While treatment success is comparable with other commercially available grafts, the rate of limb complications at 2 years is of concern. The manufacturer's instructions for use should be followed closely. Further studies are necessary to investigate the root cause of the increased rate of limb complications with the Zenith Alpha Abdominal Endovascular Graft.

End of Life Care for Unplanned Vascular Admissions

BACKGROUND

Unplanned vascular admissions have a high mortality. Previous studies have indicated that end of life care (EoLC) among this group of patients is low but there exist limited data on EoLC in the United Kingdom. The aim of this study was to evaluate the quality and predictors of EoLC for unplanned vascular admissions to a tertiary center in the United Kingdom.

METHODS

This was a retrospective single-center cohort study of unplanned vascular surgery admissions from August 1, 2019 to January 22, 2020. Data on patient demographics, markers of quality of palliative care, mortality, and cause of death of unplanned admission to the vascular surgery department were collected from hospital and general practitioner records and evaluated against EoLC to evaluate predictors and efficacy of EoLC. Quality of palliative care markers included documentation of preferred place of death and care priorities, time spent in hospital and the intensive care unit toward the end of life, and realization of documented care objectives. EoLC input was defined as a dedicated palliative care consultation (PCC) by a palliative care professional, medical doctor, surgeon, or advanced care practitioner. We also conducted a subgroup analysis of patients within this group with chronic limb-threatening ischemia (CLTI), diabetic foot, and ruptured aortic aneurysms, as all patients in this group should be offered EoLC according to international guidelines.

RESULTS

One-hundred and fifty patients were included. Median age at presentation was 70.5 years, and the cohort consisted of mostly men (72%). CLTI (31%) was the most common reason for admission. Surgical intervention was carried out in 60% of patients. Two-year mortality was 36%, and pneumonia (22%) was the most common cause of death. Seven percent of patients received PCC, which occurred a median of 10 days before death. Only a minority of patients had preferred place of care/death (14%), care priorities (37%), and family involvement during advance care planning (17%) documented in their notes; 29% of patients had Recommended Summary Plan for Emergency Care and Treatment forms in place. A diagnosis of left ventricular systolic dysfunction, chronic kidney disease, and increasing age predicted Recommended Summary Plan for Emergency Care and Treatment form completion. Patients with PCC were more likely to have advance care planning, but this did not translate into improvements in the other markers of quality of palliative and, consequently, EoLC.

CONCLUSIONS

EoLC was insufficient and of low quality despite a high mortality in this group. Clinical guidelines and pathways are needed to ensure these patients are considered for EoLC and those with CLTI, diabetic foot sepsis or ruptured abdominal aortic aneurysms are offered it by default. Further research is needed to help identify vascular patients who would benefit from EoLC earlier to improve quality at end of life.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Safety of Percutaneous Femoral Access for Endovascular Aortic Aneurysm Repair Through Previously Surgically Exposed or Repaired Femoral Arteries

OBJECTIVE

Percutaneous femoral artery access is being increasingly used in endovascular aortic repair (EVAR). The technique can be challenging in patients with previously surgically exposed or repaired femoral arteries because of excessive scar tissue. However, a successful percutaneous approach may cause less morbidity than a "re-do" open femoral approach. The aim of this study was to assess the impact of prior open surgical femoral exposure on technical success and clinical outcomes of percutaneous approach.

METHODS

This study retrospectively reviewed the clinical data of patients who underwent percutaneous EVAR between 2010 and 2020 at 2 major aortic centers. Patients were divided into 2 groups (with or without prior open surgical femoral access) for analysis of clinical outcomes. Only punctures with sheaths ≥12Fr were included for analysis. The access and (pre)closure techniques were similar in both institutions. Primary end points were intraoperative technical success, access-related revision, and access complications. A multivariate analysis was performed to identify determinants of conversion to open approach and femoral access complications in intact and re-do groins.

RESULTS

A total of 632 patients underwent percutaneous (complex) EVAR: 98 had prior open surgical femoral access and 534 patients underwent de novo femoral percutaneous access. A total of 1099 femoral artery punctures were performed: 149 in re-do and 950 in intact groins. The extent of endovascular repair included 159 infrarenal, 82 thoracic, 368 fenestrated/branched, and 23 iliac branch devices. No significant differences were seen in technical success (re-do 93.3% vs intact 95.3%, p=0.311), access-related surgical revision (0.7% vs 0.6%, p=0.950), and access complications (2.7% vs 4.0%, p=0.443). For the whole group, significant predictors for access complications in multivariate analyses were main access site (odds ratio [OR] 2.39; 95% confidence interval [CI] 1.07%-5.35%; p=0.033) and increase of the procedure time per hour (OR 1.65; 95% CI 1.34%-2.04%; p<0.001), while increase in sheath-vessel ratio had a protective effect (OR 0.33; 95% CI 0.127%-0.85%; p=0.021). Surgical conversion was predicted by main access site (OR 2.32; 95% CI 1.28%-4.19%; p=0.007) and calcification of 50% to 75% of the circumference of the access vessel (OR 3.29; 95% CI 1.38%-7.86%; p=0.005).

CONCLUSION

Within our population prior open surgical femoral artery exposure or repair had no negative impact on the technical success and clinical outcomes of percutaneous (complex) endovascular aortic aneurysm repair.

Plasma protein signatures for high on-treatment platelet reactivity to aspirin and clopidogrel in peripheral artery disease

BACKGROUND

A significant proportion of patients with peripheral artery disease (PAD) displays a poor response to aspirin and/or the platelet P2Y12 receptor antagonist clopidogrel. This phenomenon is reflected by high on-treatment platelet reactivity (HTPR) in platelet function assays in vitro and is associated with an increased risk of adverse cardiovascular events.

OBJECTIVE

This study aimed to elucidate specific plasma protein signatures associated with HTPR to aspirin and clopidogrel in PAD patients.

METHODS AND RESULTS

Based on targeted plasma proteomics, 184 proteins from two cardiovascular Olink panels were measured in 105 PAD patients. VerifyNow ASPI- and P2Y12-test values were transformed to a continuous variable representing HTPR as a spectrum instead of cut-off level-defined HTPR. Using the Boruta random forest algorithm, the importance of 3 plasma proteins for HTPR in the aspirin, six in clopidogrel and 10 in the pooled group (clopidogrel or aspirin) was confirmed. Network analysis demonstrated clusters with CD84, SLAMF7, IL1RN and THBD for clopidogrel and with F2R, SELPLG, HAVCR1, THBD, PECAM1, TNFRSF10B, MERTK and ADM for the pooled group. F2R, TNFRSF10B and ADM were higher expressed in Fontaine III patients compared to Fontaine II, suggesting their relation with PAD severity.

CONCLUSIONS

A plasma protein signature, including eight targets involved in proatherogenic dysfunction of blood cell-vasculature interaction, coagulation and cell death, is associated with HTPR (aspirin and/or clopidogrel) in PAD. This may serve as important systems-based determinants of poor platelet responsiveness to aspirin and/or clopidogrel in PAD and other cardiovascular diseases and may contribute to identify novel treatment strategies.

Human and murine fibroblast single-cell transcriptomics reveals fibroblast clusters are differentially affected by ageing and serum cholesterol

AIMS

Specific fibroblast markers and in-depth heterogeneity analysis are currently lacking, hindering functional studies in cardiovascular diseases (CVDs). Here, we established cell-type markers and heterogeneity in murine and human arteries and studied the adventitial fibroblast response to CVD and its risk factors hypercholesterolaemia and ageing.

METHODS AND RESULTS

Murine aorta single-cell RNA-sequencing analysis of adventitial mesenchymal cells identified fibroblast-specific markers. Immunohistochemistry and flow cytometry validated platelet-derived growth factor receptor alpha (PDGFRA) and dipeptidase 1 (DPEP1) across human and murine aorta, carotid, and femoral arteries, whereas traditional markers such as the cluster of differentiation (CD)90 and vimentin also marked transgelin+ vascular smooth muscle cells. Next, pseudotime analysis showed multiple fibroblast clusters differentiating along trajectories. Three trajectories, marked by CD55 (Cd55+), Cxcl chemokine 14 (Cxcl14+), and lysyl oxidase (Lox+), were reproduced in an independent RNA-seq dataset. Gene ontology (GO) analysis showed divergent functional profiles of the three trajectories, related to vascular development, antigen presentation, and/or collagen fibril organization, respectively. Trajectory-specific genes included significantly more genes with known genome-wide associations (GWAS) to CVD than expected by chance, implying a role in CVD. Indeed, differential regulation of fibroblast clusters by CVD risk factors was shown in the adventitia of aged C57BL/6J mice, and mildly hypercholesterolaemic LDLR KO mice on chow by flow cytometry. The expansion of collagen-related CXCL14+ and LOX+ fibroblasts in aged and hypercholesterolaemic aortic adventitia, respectively, coincided with increased adventitial collagen. Immunohistochemistry, bulk, and single-cell transcriptomics of human carotid and aorta specimens emphasized translational value as CD55+, CXCL14+ and LOX+ fibroblasts were observed in healthy and atherosclerotic specimens. Also, trajectory-specific gene sets are differentially correlated with human atherosclerotic plaque traits.

CONCLUSION

We provide two adventitial fibroblast-specific markers, PDGFRA and DPEP1, and demonstrate fibroblast heterogeneity in health and CVD in humans and mice. Biological relevance is evident from the regulation of fibroblast clusters by age and hypercholesterolaemia in vivo, associations with human atherosclerotic plaque traits, and enrichment of genes with a GWAS for CVD.

End of Life Care and Advance Care Planning for Outpatients with Inoperable Aortic Aneurysms

OBJECTIVE

A significant proportion of patients with abdominal and thoracic aortic aneurysms (AA) do not proceed to intervention after reaching treatment threshold diameter due to a combination of poor cardiovascular reserve, frailty and aortic morphology. This patient cohort has a high mortality, however, until this study, there exist no studies on the end of life care conservatively managed patients receive.

DESIGN

This is a retrospective multicentre cohort study of 220 conservatively managed AA patients referred to Leeds Vascular Institute (UK) and Maastricht University Medical Centre (Netherlands) for intervention between 2017 and 2021.

METHODS

Demographic details, mortality, cause of death, advance care planning and palliative care outcomes were analysed to examine predictors of palliative care referral and efficacy of palliative care consultation.

RESULTS

A total of 1506 AA patients were seen over this time period, giving a non-intervention rate of 15%. There was a 3-year mortality rate of 55%, a median survival of 364 days and rupture was the reported cause of death in 18% of the decedents. Median follow up was 34 months. Only 8% of all patients and 16% of decedents received palliative care consultation, which took place a median of 3.5 days before death. Patients over 81 years of age were more likely to have advance care planning. Only 5% and 23% of conservatively managed patients had documentation of preferred place of death and care priorities respectively. Patients with palliative care consultation were more likely to have these in place.

CONCLUSION

Only a small proportion of conservatively treated patients had advance care planning and this was far below international guidelines on end of life care for adults, which recommend it for each of these patients. Pathways and guidance should be implemented to ensure patients not offered AA intervention receive end of life care and advance care planning.

Fenestrated/branched endovascular aortic repair using unilateral femoral access in patients with iliac occlusive disease

OBJECTIVE

Fenestrated/branched endovascular aortic repair (F/BEVAR) in patients with occluded iliac arteries is challenging owing to limited access for branch vessel catheterization and increased risk for leg and spinal ischemic complications. The aim of this study was to analyze technical strategies and outcomes of F/BEVAR in patients with unilateral iliofemoral occlusive disease.

METHODS

We performed a retrospective review of all consecutive patients treated by F/BEVAR in two institutions (2003-2021). Patients with unilateral iliofemoral occlusive disease were included in the analysis. All patients had one patent iliac artery that was used for advancement of the fenestrated-branch component. Preloaded catheter/guidewire systems or steerable sheaths were used as adjuncts to facilitate catheterization. Primary endpoints were technical success, mortality, major adverse events (stroke, spinal cord injury, dialysis or decrease in the glomerular filtration rate of more than 50%, bowel ischemia, myocardial infarction, or respiratory failure), primary iliac patency, and freedom from reinterventions.

RESULTS

There were 959 patients treated with F/BEVAR. Of these, 15 patients (1.56%; mean age, 74 years; 80% male) had occluded iliac arteries and 1 patent iliofemoral access and were treated for a thoracoabdominal aortic aneurysm (n = 8) or juxtarenal abdominal aortic aneurysm (n = 7). Brachial access was used in 14 of the 15 patients and preloaded systems in 7 of the 15 patients (47%). The remaining 53% had staggered deployment of stent grafts. There were seven physician-modified endovascular grafts, seven custom-made devices, and one off-the-shelf device used. Thirteen patients (87%) had distal seal using aortouni-iliac stent grafts and two (13%) had distal seal in the infrarenal aorta. Concomitant femoral crossover bypass (FCB) was performed in two patients and six patients had a prior FCB. Technical success was 100%. There were no intraoperative complications or early lower extremity ischemic complications, and all FCB were preserved. There was one mortality (7%) within 30 days owing to retrograde type A dissection. Major adverse events occurred in 20% of patients. The median follow-up was 12 months (range, 0-85 months). Two patients (13%) required three reinterventions. One patient required proximal stent graft extension for an acute type B dissection (3 months) and another required iliac extension for type Ib endoleak of an aortouni-iliac graft (21 months) and thrombolysis of that extension (50 months). At last follow-up, all patients had primary graft patency except one with secondary graft patency without new claudication. One patient had a single renal artery stent occlusion at follow-up with no r-intervention. The overall survival rate was 60%, without aortic-related deaths.

CONCLUSIONS

Although challenging, F/BEVAR with unilateral femoral/brachial approach is feasible in patients with occluded iliac limbs, with an important rate of ischemic complications, but satisfactory outcomes.

Impact of the COVID-19 pandemic on surgical care in the Netherlands

BACKGROUND

The COVID-19 pandemic caused disruption of regular healthcare leading to reduced hospital attendances, repurposing of surgical facilities, and cancellation of cancer screening programmes. This study aimed to determine the impact of COVID-19 on surgical care in the Netherlands.

METHODS

A nationwide study was conducted in collaboration with the Dutch Institute for Clinical Auditing. Eight surgical audits were expanded with items regarding alterations in scheduling and treatment plans. Data on procedures performed in 2020 were compared with those from a historical cohort (2018-2019). Endpoints included total numbers of procedures performed and altered treatment plans. Secondary endpoints included complication, readmission, and mortality rates.

RESULTS

Some 12 154 procedures were performed in participating hospitals in 2020, representing a decrease of 13.6 per cent compared with 2018-2019. The largest reduction (29.2 per cent) was for non-cancer procedures during the first COVID-19 wave. Surgical treatment was postponed for 9.6 per cent of patients. Alterations in surgical treatment plans were observed in 1.7 per cent. Time from diagnosis to surgery decreased (to 28 days in 2020, from 34 days in 2019 and 36 days in 2018; P < 0.001). For cancer-related procedures, duration of hospital stay decreased (5 versus 6 days; P < 0.001). Audit-specific complications, readmission, and mortality rates were unchanged, but ICU admissions decreased (16.5 versus 16.8 per cent; P < 0.001).

CONCLUSION

The reduction in the number of surgical operations was greatest for those without cancer. Where surgery was undertaken, it appeared to be delivered safely, with similar complication and mortality rates, fewer admissions to ICU, and a shorter hospital stay.

Identification of a PRDM1-regulated T cell network to regulate T cell driving plaque inflammation in human and mouse atherosclerosis

 

T cells have a prominent role in the pathogenesis of atherosclerosis, although their exact function remains elusive. Here, we pursued a network-driven approach to identify T cell-associated gene programs driving the transition from low- to high-risk human plaques.

In this study 43 human carotid arterial plaques were collected and stratified based on absence (low-risk) or presence (high-risk) of intraplaque haemorrhage (IPH). Lesion RNA was subjected to microarray gene expression analysis and analysed by Weighted Gene Co-expression Network Analysis (WGCNA). We identified a co-expressed gene cluster displaying a strong T cell signalling signature in high- versus low-risk plaque, which was tightly connected to subnetworks of angiogenesis and interferon-signalling. WGCNA-based Bayesian network inference, cell-type deconvolution and single-cell gene expression revealed that this T cell-associated gene program was likely linked to effector-memory cytotoxic CD8+ T cells, underpinning the central role of T cells in plaque destabilization. Gene regulatory analysis identified cytotoxic T cell-related transcription factors, like PRDM1, regulating this plaque T cell gene program. Moreover, we demonstrated in LDL receptor knockout mice with T cell-specific Prdm1 deficiency, that lack of Prdm1 in T cells resulted in larger, more advanced plaques.

In conclusion, our study reveals a PRDM1-regulated T cell footprint in high- versus low-risk human atherosclerotic lesions and murine atherosclerotic plaque development, thereby identifying this network as a potential target for intervention in adverse T cell responses.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): The European Research Area Network on Cardiovascular Diseases (ERA-CVD and Dutch Heart Foundation)

Multicenter Experience of Upper Extremity Access in Complex Endovascular Aortic Aneurysm Repair

PURPOSE

Upper extremity access (UEA) for antegrade cannulation of aortic side branches is a relevant part of endovascular treatment of complex aortic aneurysms and can be achieved using several techniques, sites and sides. The purpose of this study was to evaluate different UEA strategies in a multicenter registry of complex endovascular aortic aneurysm repair (EVAR).

METHODS

In six aortic centers in the Netherlands, all endovascular aortic procedures from 2006 to 2019 were retrospectively reviewed. Patients who received upper extremity access during complex EVAR were included. Primary outcome was a composite endpoint of any access complication, excluding minor hematomas. Secondary outcomes were access characteristics, access complications considered individually, access reinterventions and incidence of ischemic cerebrovascular events.

RESULTS

417 patients underwent 437 UEA for 303 fenestrated/branched EVARs, and 114 chimney EVARs. Twenty patients had bilateral, 295 left-sided, and 102 right-sided UEA. 413 approaches were performed surgically and 24 percutaneously. Distal brachial access was used in 89 cases, medial brachial in 149, proximal brachial in 140 and axillary access in 59 cases. No significant differences regarding the composite endpoint of access complications were seen (DBA 11.3% vs. MBA 6.7% vs. PBA 13.6% vs. AA 10.2%; p=.29). Postoperative neuropathy occurred most after proximal brachial access (DBA 1.1% vs. MBA 1.3% vs. PBA 9.3 % vs. AA 5.1%; p=.003). There were no differences in cerebrovascular complications between access sides (right 5.9% vs. left 4.1% vs. bilateral 5%; p=.75). Significantly more overall access complications were seen after a percutaneous approach (29.2% vs. 6.8%; p=.002). In multivariate analysis the risk for access complications after open approach was decreased by male gender (OR 0.27; CI 95% 0.10 - 0.72; p= .009), while an increase in age per year (OR 1.08; CI 95% 1.004 - 1.179; p=.039) and diabetes mellitus type 2 (OR 3.70; CI 95% 1.20 - 11.41; p= .023) increased the risk.

CONCLUSION

Between the four access localizations, there were no differences in overall access complications. Female gender, diabetes mellitus type 2 and ageing increased the risk for access complications after surgical approach. Furthermore, a percutaneous upper extremity access resulted in higher complication rates than a surgical approach.

Identification of CD8+ T cell PRDM1 in high-risk human plaques and its regulatory role in murine lesion development

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Fritz Thyssen Stiftung

T cells have a prominent role in the pathogenesis of atherosclerosis, although their function in atherosclerotic plaques is only partly understood. In this study, we utilize the advantages of high-throughput techniques and data analytic strategies to compare the inherent biological changes of T cells during plaque transition from a stable, non-haemorrhaged (low-risk) to a rupture-prone, haemorrhaged (high-risk) phenotype.

We classified 43 human carotid arterial lesions into high- and low-risk plaques based on the presence/absence of intraplaque hemorrhages. RNA from these lesions was isolated and microarray gene expression data was obtained and analyzed by Weighted Gene Co-expression Network Analysis. A strong T cell signalling signature was identified in high- versus low-risk plaques, influencing angiogenesis and interferon-related processes. Bayesian network inference, cell type deconvolution and single-cell RNA sequencing analysis revealed that the T cell-associated gene program was linked to effector-memory cytotoxic, CD8+ T cells. This gene program appeared driven by CD8+ T cell-related transcription factors, including RUNX3, IRF7 and most importantly PRDM1. To validate these findings, we demonstrated in a murine model that T cell PRDM1 plays a key role in plaque formation, as atherosclerotic mice with a T cell specific Prdm1 deficiency developed larger and more advanced atherosclerotic plaques compared to control mice.

In conclusion, our study unveils a clear PRDM1-regulated effector-memory cytotoxic CD8+ T cell footprint in plaque development and the shift from low- to high-risk plaques, thereby revealing CD8+ T cells and PRMD1 as potential targets for intervention in adverse T cell responses in human atherosclerotic lesions.

Association of Hospital Volume with Perioperative Mortality of Endovascular Repair of Complex Aortic Aneurysms: A Nationwide Cohort Study

OBJECTIVE

We evaluate nationwide perioperative outcomes of complex EVAR and assess the volume-outcome association of complex EVAR.

SUMMARY OF BACKGROUND DATA

Endovascular treatment with fenestrated (FEVAR) or branched (BEVAR) endografts is progressively used for excluding complex aortic aneurysms (complex AAs). It is unclear if a volume-outcome association exists in endovascular treatment of complex AAs (complex EVAR).

METHODS

All patients prospectively registered in the Dutch Surgical Aneurysm Audit who underwent complex EVAR (FEVAR or BEVAR) between January 2016 and January 2020 were included. The effect of annual hospital volume on perioperative mortality was examined using multivariable logistic regression analyses. Patients were stratified into quartiles based on annual hospital volume to determine hospital volume categories.

RESULTS

We included 694 patients (539 FEVAR patients, 155 BEVAR patients). Perioperative mortality following FEVAR was 4.5% and 5.2% following BEVAR. Postoperative complication rates were 30.1% and 48.7%, respectively. The first quartile hospitals performed <9 procedures/yr; second, third, and fourth quartile hospitals performed 9-12, 13-22, and ≥23 procedures/yr. The highest volume hospitals treated the significantly more complex patients. Perioperative mortality of complex EVAR was 9.1% in hospitals with a volume of < 9, and 2.5% in hospitals with a volume of ≥13 (P = 0.008). After adjustment for confounders, an annual volume of ≥13 was associated with less perioperative mortality compared to hospitals with a volume of < 9.

CONCLUSIONS

Data from this nationwide mandatory quality registry shows a significant effect of hospital volume on perioperative mortality following complex EVAR, with high volume complex EVAR centers demonstrating lower mortality rates.

An International, Multicenter Retrospective Observational Study to Assess Technical Success and Clinical Outcomes of Patients Treated with an Endovascular Aneurysm Sealing Device for Type III Endoleak

INTRODUCTION

Type III endoleaks post-endovascular aortic aneurysm repair (EVAR) warrant treatment because they increase pressure within the aneurysm sac leading to increased rupture risk. The treatment may be difficult with regular endovascular devices. Endovascular aneurysm sealing (EVAS) might provide a treatment option for type III endoleaks, especially if located near the flow divider. This study aims to analyze clinical outcomes of EVAS for type III endoleaks after EVAR.

METHODS

This is an international, retrospective, observational cohort study including data from 8 European institutions.

RESULTS

A total of 20 patients were identified of which 80% had a type IIIb endoleak and the remainder (20%) a type IIIa endoleak. The median time between EVAR and EVAS was 49.5 months (28.5-89). Mean AAA diameter prior to EVAS revision was 76.6±19.9 mm. Technical success was achieved in 95%, 1 patient had technical failure due to a postoperative myocardial infarction resulting in death. Mean follow-up was 22.8±15.2 months. During follow-up 1 patient had a type Ia endoleak, and 1 patient had a new type IIIa endoleak at an untreated location. There were 5 patients with aneurysm growth. Five patients underwent AAA-related reinterventions indications being: growth with type II endoleak (n=3), type Ia endoleak (n=1), and iliac aneurysm (n=1). At 1-year follow-up, the freedom from clinical failure was 77.5%, freedom from all-cause mortality 94.7%, freedom from aneurysm-related mortality 95%, and freedom from aneurysm-related reinterventions 93.8%.

CONCLUSION

The EVAS relining can be safely performed to treat type III endoleaks with an acceptable technical success rate, a low 30-day mortality rate and no secondary ruptures at short-term follow-up. The relatively low clinical success rates, related to reinterventions and AAA enlargement, highlight the need for prolonged follow-up.

Integrative multiomics analysis of human atherosclerosis reveals a serum response factor-driven network associated with intraplaque hemorrhage

BACKGROUND

While single-omics analyses on human atherosclerotic plaque have been very useful to map stage- or disease-related differences in expression, they only partly capture the array of changes in this tissue and suffer from scale-intrinsic limitations. In order to better identify processes associated with intraplaque hemorrhage and plaque instability, we therefore combined multiple omics into an integrated model.

METHODS

In this study, we compared protein and gene makeup of low- versus high-risk atherosclerotic lesion segments from carotid endarterectomy patients, as judged from the absence or presence of intraplaque hemorrhage, respectively. Transcriptomic, proteomic, and peptidomic data of this plaque cohort were aggregated and analyzed by DIABLO, an integrative multivariate classification and feature selection method.

RESULTS

We identified a protein-gene associated multiomics model able to segregate stable, nonhemorrhaged from vulnerable, hemorrhaged lesions at high predictive performance (AUC >0.95). The dominant component of this model correlated with αSMA- PDGFRα+ fibroblast-like cell content (p = 2.4E-05) and Arg1+ macrophage content (p = 2.2E-04) and was driven by serum response factor (SRF), possibly in a megakaryoblastic leukemia-1/2 (MKL1/2) dependent manner. Gene set overrepresentation analysis on the selected key features of this model pointed to a clear cardiovascular disease signature, with overrepresentation of extracellular matrix synthesis and organization, focal adhesion, and cholesterol metabolism terms, suggestive of the model's relevance for the plaque vulnerability. Finally, we were able to corroborate the predictive power of the selected features in several independent mRNA and proteomic plaque cohorts.

CONCLUSIONS

In conclusion, our integrative omics study has identified an intraplaque hemorrhage-associated cardiovascular signature that provides excellent stratification of low- from high-risk carotid artery plaques in several independent cohorts. Further study revealed suppression of an SRF-regulated disease network, controlling lesion stability, in vulnerable plaque, which can serve as a scaffold for the design of targeted intervention in plaque destabilization.

DEFICIENCY OF MYELOID PHD PROTEINS AGGRAVATES ATHEROGENESIS VIA MACROPHAGE APOPTOSIS AND PARACRINE FIBROTIC SIGNALING: Atherogenic effects of myeloid PHD knockdown

Aims

Atherosclerotic plaque hypoxia is detrimental for macrophage function. Prolyl hydroxylases (PHDs) initiate cellular hypoxic responses, possibly influencing macrophage function in plaque hypoxia. Thus, we aimed to elucidate the role of myeloid PHDs in atherosclerosis.

Methods and results

Myeloid-specific PHD knockout (PHDko) mice were obtained via bone marrow transplantation (PHD1ko, PHD3ko) or conditional knockdown through lysozyme M-driven Cre recombinase (PHD2cko). Mice were fed high cholesterol diet for 6–12 weeks to induce atherosclerosis. Aortic root plaque size was significantly augmented 2.6-fold in PHD2cko, and 1.4-fold in PHD3ko compared to controls but was unchanged in PHD1ko mice. Macrophage apoptosis was promoted in PHD2cko and PHD3ko mice in vitro and in vivo, via the hypoxia-inducible factor (HIF) 1α/BNIP3 axis. Bulk and single-cell RNA data of PHD2cko bone marrow-derived macrophages (BMDMs) and plaque macrophages, respectively, showed enhanced HIF1α/BNIP3 signalling, which was validated in vitro by siRNA silencing. Human plaque BNIP3 mRNA was positively associated with plaque necrotic core size, suggesting similar pro-apoptotic effects in human. Furthermore, PHD2cko plaques displayed enhanced fibrosis, while macrophage collagen breakdown by matrix metalloproteinases, collagen production, and proliferation were unaltered. Instead, PHD2cko BMDMs enhanced fibroblast collagen secretion in a paracrine manner. In silico analysis of macrophage-fibroblast communication predicted SPP1 (osteopontin) signalling as regulator, which was corroborated by enhanced plaque SPP1 protein in vivo. Increased SPP1 mRNA expression upon PHD2cko was preferentially observed in foamy plaque macrophages expressing ‘triggering receptor expressed on myeloid cells-2’ (TREM2hi) evidenced by single-cell RNA, but not in neutrophils. This confirmed enhanced fibrotic signalling by PHD2cko macrophages to fibroblasts, in vitro as well as in vivo.

Conclusion

Myeloid PHD2cko and PHD3ko enhanced atherosclerotic plaque growth and macrophage apoptosis, while PHD2cko macrophages further activated collagen secretion by fibroblasts in vitro, likely via paracrine SPP1 signalling through TREM2hi macrophages.

Use of covered stent grafts as treatment of traumatic venous injury to the inferior vena cava and iliac veins: A systematic review

OBJECTIVE

Venous injury to the inferior vena cava or iliac veins is rare but can result in high mortality rates. Traditional treatment by repair or ligation can be technically demanding. A relatively new treatment modality is the use of a covered stent to cover the venous defect. The aim of the present systematic review was to assess the techniques, results, and challenges of covered stent graft repair of traumatic injury to the inferior vena cava and iliac veins.

METHODS

The PubMed (Medline) and Embase databases were systematically searched up to September 2020 by two of us (R.R.S. and D.D.) independently for studies reporting on covered stenting of the inferior vena cava or iliac veins after traumatic or iatrogenic injury. A methodologic quality assessment was performed using the modified Newcastle-Ottawa scale. Data were extracted for the following parameters: first author, year of publication, study design, number of patients, type and diameter of the stent graft, hemostatic success, complications, mortality, postoperative medication, follow-up type and duration, and venous segment patency. The main outcome was clinical success of the intervention, defined as direct hemostasis, with control of hemorrhage, hemodynamic recovery, and absence of contrast extravasation.

RESULTS

From the initial search, which yielded 1884 records, a total of 28 studies were identified for analysis. All reports consisted of case reports, except for one retrospective cohort study and one case series. A total of 35 patients had been treated with various covered stent grafts, predominantly thoracic or abdominal aortic endografts. In all patients, the treatment was technically successful. The 30-day mortality rate for the entire series was 2.9%. Three perioperative complications were described: one immediate stent occlusion, one partial thrombosis, and one pulmonary embolism. Additional in-stent thrombus formation was seen during follow-up in three patients, leading to one stent graft occlusion (asymptomatic). The postoperative anticoagulation strategy was highly heterogeneous. The median follow-up was 3 months (range, 0.1-84 months). However, follow-up with imaging studies was not performed in all cases.

CONCLUSIONS

In selected cases of injury to the inferior vena cava and iliac veins, covered stent grafts can be successful for urgent hemostasis with good short-term results. Data on long-term follow-up are very limited.

Haemodynamic optimisation of a dialysis graft design using a global optimisation approach

Disturbed flow and the resulting non-physiological wall shear stress (WSS) at the graft-vein anastomosis play an important role in arteriovenous graft (AVG) patency loss. Modifying graft geometry with helical features is a popular approach to minimise the occurrence of detrimental haemodynamics and to potentially increase graft longevity. Haemodynamic optimisation of AVGs typically requires many computationally expensive computational fluid dynamics (CFD) simulations to evaluate haemodynamic performance of different graft designs. In this study, we aimed to develop a haemodynamically optimised AVG by using an efficient meta-modelling approach. A training dataset containing CFD evaluations of 103 graft designs with helical features was used to develop computationally low-cost meta-models for haemodynamic metrics related to graft dysfunction. During optimisation, the meta-models replaced CFD simulations that were otherwise needed to evaluate the haemodynamic performance of possible graft designs. After optimisation, haemodynamic performance of the optimised graft design was verified using a CFD simulation. The obtained optimised graft design contained both a helical graft centreline and helical ridge. Using the optimised design, the magnitude of flow disturbances and the size of the anastomotic areas exposed to non-physiological WSS was successfully reduced compared to a regular straight graft. Our meta-modelling approach allowed to reduce the total number of CFD model evaluations required for our design optimisation by approximately a factor 2000. The applied efficient meta-modelling technique was successful in identifying an optimal, helical graft design at relatively low computational costs. Future studies should evaluate the in vivo benefits of the developed graft design.

Mechanical ventilation variability due to tracheal compression in a patient with a mycotic descending aortic aneurysm: an inverse correlation with blood pressure

Mycotic aortic aneurysms carry significant morbidity and mortality. In the current report, we present a case of a patient with a mycotic descending aortic aneurysm with contained rupture causing variable compression of the trachea, influenced by a variability in blood pressure. In these patients, blood pressure management is paramount as relative hypertensive periods do not only increase the risk of rupture but can also warrant high ventilation pressures or can potentially result in airway occlusion.

Editor's Choice - Mortality and Major Amputation after Revascularisation in Octogenarians Versus Non-Octogenarians with Chronic Limb Threatening Ischaemia: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this systematic review and meta-analysis was to assess the clinical outcomes after revascularisation in octogenarians with chronic limb threatening ischaemia (CLTI).

METHODS

This was a systematic review and meta-analysis, in which the Medline, Embase, and Cochrane Library databases were searched systematically by two independent researchers. Meta-analyses were performed to analyse one year mortality, one year major amputation, and one year amputation free survival (AFS) after revascularisation. Pooled outcome estimates were reported as percentages and odds ratio (OR) with 95% confidence intervals (CI). In addition, sensitivity and subgroup analyses were performed and the quality of evidence was determined according to the GRADE system.

RESULTS

The review includes 21 observational studies with patients who were treated for CLTI. Meta-analysis of 12 studies with a total of 17 118 patients was performed. A mortality rate of 32% was found in octogenarians (95% CI 27-37%), which was significantly higher than in the non-octogenarians (17%, 95% CI 11-22%/OR 2.52, 95% CI 1.93-3.29; GRADE: "low"). No significant difference in amputation rate was found (octogenarians 15%, 95% CI 11-18%; non-octogenarians 12%, 95% CI 7-14%; GRADE: "very low"). AFS was significantly lower in the octogenarian group (OR 1.55, 95% CI 1.03-2.43; GRADE: "very low"). In a subgroup analysis differentiating between endovascular and surgical revascularisation, amputation rates were comparable. For octogenarians, those treated conservatively had a mortality rate significantly higher than those treated by revascularisation (OR 1.76, 95% CI 1.19-2.60; GRADE: "very low"). No significant difference in mortality rate was found between primary amputation and revascularisation in octogenarians (OR 0.70, 95% CI 0.24-2.03; GRADE: "very low").

CONCLUSION

In octogenarians with CLTI, a substantial one year mortality rate of 32% was found after revascularisation. The amputation rates were comparable between both age groups. However, only low quality evidence could be obtained supporting the results of this meta-analysis because only observational studies were available for inclusion.

Can Electric Nose Breath Analysis Identify Abdominal Wall Hernia Recurrence and Aortic Aneurysms? A Proof-of-Concept Study

Introduction. This pilot study evaluates if an electronic nose (eNose) can distinguish patients at risk for recurrent hernia formation and aortic aneurysm patients from healthy controls based on volatile organic compound analysis in exhaled air. Both hernia recurrence and aortic aneurysm are linked to impaired collagen metabolism. If patients at risk for hernia recurrence and aortic aneurysms can be identified in a reliable, low-cost, noninvasive manner, it would greatly enhance preventive options such as prophylactic mesh placement after abdominal surgery. Methods. From February to July 2017, a 3-armed proof-of-concept study was conducted at 3 hospitals including 3 groups of patients (recurrent ventral hernia, aortic aneurysm, and healthy controls). Patients were measured once at the outpatient clinic using an eNose with 3 metal-oxide sensors. A total of 64 patients (hernia, n = 29; aneurysm, n = 35) and 37 controls were included. Data were analyzed by an automated neural network, a type of self-learning software to distinguish patients from controls. Results. Receiver operating curves showed that the automated neural network was able to differentiate between recurrent hernia patients and controls (area under the curve 0.74, sensitivity 0.79, and specificity 0.65) as well as between aortic aneurysm patients and healthy controls (area under the curve 0.84, sensitivity 0.83, and specificity of 0.81). Conclusion. This pilot study shows that the eNose can distinguish patients at risk for recurrent hernia and aortic aneurysm formation from healthy controls.

Comparing Mobile C-Arm with a Hybrid Operating Room for Imaging in Fenestrated Stent-Graft Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

To evaluate the advantages of a hybrid operating room (OR) (group 2) compared with a fluoroscopic mobile C-arm (group 1) during fenestrated stent-graft endovascular aneurysm repair (f-EVAR).

METHODS

This single-center study retrospectively analyzed prospectively collected data of consecutive patients treated with f-EVAR for short-necked, juxtarenal, and suprarenal aortic aneurysms between January 2006 and July 2016. Primary end points were technical success and perioperative complications. Secondary end points included 30-day and 1-year mortality as well as target vessel patency.

RESULTS

About 96 patients were treated (85 men; 74.1 ± 6.3 years); 46 patients (48%) belonging to group 1 and 50 (52%) patients belonging to group 2. Technical success was achieved in 92.7% of the procedures (group 1 91.3% vs. group 2 94%, P = 0.72). Significantly more complex interventions were performed in group 2 (n = 38 of 50) compared with group 1 (n = 14 of 46; P < 0.001), in which primarily renal f-EVAR interventions were performed. In group 2, significantly less contrast was used (median 150 mL vs. 100 mL; P < 0.001). The 30-day mortality in group 1 was 9% and 2% in group 2 (P = 0.14), and 1-year survival was also not significantly different between both groups. Target visceral vessel primary patency was significantly higher in group 1 (87.6% vs. 85.5% [P = 0.006] and 83.8% vs. 78.3% [P = 0.03]) at 6 and 12 months, respectively). There was no significant difference in renal artery primary patency at 6 and 12 months.

CONCLUSIONS

Immediate and 1-year outcomes after f-EVAR for abdominal aortic aneurysm were comparable using a hybrid OR compared with a mobile C-arm, despite the use of significantly more complex stent grafts in the patients treated in the hybrid OR. The use of a hybrid OR may assist in achieving satisfying results in complex f-EVAR.

Cerebrovascular Complications After Upper Extremity Access for Complex Aortic Interventions: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this study was to review the risk of developing cerebrovascular complications from upper extremity access during endovascular treatment of complex aortic aneurysms.

METHODS

A systematic review and meta-analysis were conducted according to the PRISMA guideline. An electronic search of the public domains Medline (PubMed), Embase (Ovid), Web of Science and Cochrane Library was performed to identify studies related to the treatment of aortic aneurysms involving upper extremity access. Meta-analysis was used to compare the rate of cerebrovascular event after left, right and bilateral upper extremity access. Results are presented as relative risk (RR) and 95% confidence intervals (CIs).

RESULTS

Thirteen studies including 1276 patients with complex endovascular treatment of aortic aneurysms using upper extremity access were included in the systematic review. Left upper extremity access (UEA) was used in 1028 procedures, right access in 148 and bilateral access in 100 procedures. The rate of cerebrovascular complications for patients treated through left UEA was 1.7%, through right UEA 4% and through bilateral UEA 5%. In the meta-analysis, we included seven studies involving 645 patients treated with a left upper extremity access, 87 patients through a right and 100 patients through a bilateral upper extremity access. Patients, who underwent right-sided (RR 5.01, 95% CI 1.51-16.58, P = 0.008) or bilateral UEA (RR 4.57, 95% CI 1.23-17.04, P = 0.02), had a significantly increased risk of cerebrovascular events compared to those who had a left-sided approach.

CONCLUSION

Left upper extremity access is associated with a significantly lower rate of cerebrovascular complications as compared to right or bilateral upper extremity access.

A systematic review on the use of muscle flaps for deep groin infection following vascular surgery

OBJECTIVE

The aim of this systematic review is to assess potential differences in effectiveness (graft loss and limb loss) between the sartorius muscle flap (SMF) and the rectus femoris muscle flap (RFF) coverage technique for deep groin wound infection following vascular surgery. Our hypothesis was that RFF reconstruction is more effective in groin coverage.

METHODS

The PubMed, Embase, and Medline databases were systematically searched by two independent researchers for articles reporting effectiveness of both muscle flaps in the treatment of groin infections following vascular surgery. After quality assessment using the Newcastle-Ottawa Scale and Methodological Index for NOn-Randomized studies (MINOR) scores and data extraction, individual results of the included studies were reviewed. Weighted pooled outcome estimates were calculated.

RESULTS

A total of 17 studies comprising 544 SMF reconstructions and 238 RFF reconstructions were included. The pooled flap survival rate was 100% in both groups, with a pooled amputation rate of 0% and 2%, respectively. In the RFF group, a pooled 30-day mortality rate of 0% was found, compared with 1% in the SMF group. Pooled graft loss rates were 2% in the RFF group and 21% in the SMF group. Only one head-to-head comparison between both muscle flaps was performed, finding no significant differences.

CONCLUSIONS

Deep groin infection after vascular surgery can be treated with debridement and local muscle flap coverage. In this systematic review, superiority of either muscle flap on amputation or mortality rates was not demonstrated; however, there was a lower rate of vascular graft loss after RFF reconstruction. These conclusions are based on low-quality evidence because of limited data. Local muscle flap reconstruction using both techniques is effective in the treatment of infected groin wounds, achieving good results in a fragile group of patients. Therefore, anatomical and patient characteristics, which were not assessed in this analysis, are critical in the decision-making process on which muscle flap reconstruction is the best treatment option for an individual patient.

A Stopped Pilot Study of the ProGlide Closure Device After Transbrachial Endovascular Interventions

Purpose: To evaluate the feasibility and safety of the suture-mediated ProGlide device in closure of the brachial artery after endovascular interventions. Materials and Methods: From 2016 to 2017, a pilot study was performed using the ProGlide to achieve hemostasis after percutaneous access of distal brachial arteries >4 mm in diameter. In an interim analysis, the results were compared to a matched control group taken from a 60-patient historical cohort who underwent brachial artery access and manual compression to achieve hemostasis between 2014 and 2017. The primary outcome was access-related reintervention and the secondary outcome was the incidence of access-site complications. Results: Seven patients (mean age 67.9 years; 6 men) were enrolled in the study before it was stopped in 2017. Four patients experienced 6 access-site complications (neuropathy, hematoma, occlusion, and pseudoaneurysm). These resulted in 3 access-related reinterventions: surgical evacuation of a hematoma, thrombectomy of the occluded brachial artery, and surgical repair of the pseudoaneurysm. In the interim comparison to the 19 matched patients (mean age 61.9 years; 6 men), the ProGlide group had proportionally more patients experiencing access-related complications (57% vs 16% for manual compression, p=0.035) and resultant reinterventions (43% vs 11%, p=0.064). Based on this data the trial was stopped. Conclusion: Considering this experience, it is not advisable to use the ProGlide in transbrachial endovascular interventions due to the high incidence of complications and access-related reinterventions.

Searching for a Common Thrombo-Inflammatory Basis in Patients With Deep Vein Thrombosis or Peripheral Artery Disease

Background: Inflammation and hypercoagulability play a pivotal role in venous thromboembolism and atherothrombosis. Since venous thrombosis increases the risk of atherothrombotic events and vice versa, common mechanisms may be involved.

Objectives: To elucidate the role of neutrophils and coagulation in the occurrence of atherothrombotic events in patients with a history of deep vein thrombosis (DVT or peripheral artery disease (PAD).

Materials and Methods: We studied 115 patients from two cohorts (75 DVT, 40 PAD). From those with PAD, 20 patients had progressive disease; from those with DVT, 25 patients had a recurrent DVT and 25 suffered from post thrombotic syndrome (PTS); patients were age and sex matched to DVT and PAD patients without events. Markers of neutrophil recruitment (p-selectin) and activation [nucleosomes, human neutrophil elastase- α1anti-trypsin (HNE-AT)], an anti-inflammatory marker (Lipoxin A4) and a clotting activity marker (d-dimer), were measured with ELISA. Coagulation potential was analyzed by thrombin generation (CAT method).

Results: Higher nucleosome levels were found in DVT patients [11.3 U/mL (7.4–17.7)] compared to PAD patients [7.1 U/mL (5.1–13.8)], lower HNE-AT levels were found in DVT patients [33.4 ng/mL (23.5–40.5)] in comparison to PAD patients [158 ng/mL (88.1–283)]. No difference in nucleosome levels was found between DVT patients with cardiovascular (CV) events [12.6 U/mL (8.2–16.1)], and PAD patients with CV events [6.9 U/mL (4.9–11.2)]. Lipoxin A4 levels appeared to be significantly lower in DVT [2.4 ng/mL (1.7–4.8)] vs. PAD [35.6 ng/mL (16.6–80.1)], with similar results in DVT patients with CV events vs. PAD patients with CV events. Thrombin generation showed higher ETP [160.4% (141.1–215.4)], and peak height [292.1% (177.9–330)] values in DVT patients. D-dimer levels were significantly lower in the DVT cohort [330 ng/mL (220–550)] compared to the PAD cohort [550 ng/mL (369–959)].

Conclusion: In DVT patients, neutrophil activity does not appear to be an important driver of CV events. Although neutrophil activity is more pronounced in PAD, its effect is partly dampened by Lipoxin A4. Moreover, no associations were found between NET products and coagulation activity, suggesting that neutrophil activation does not play a pivotal role in the risk of thrombosis in either DVT or PAD.

Transradial Approach for Aortoiliac and Femoropopliteal Interventions: A Systematic Review and Meta-analysis

PURPOSE

To present a systematic review and meta-analysis comparing the transradial approach for aortoiliac and femoropopliteal interventions to the traditional transfemoral access.

METHODS

A search of the public domain databases MEDLINE, SCOPUS, Web of Science, and Cochrane Library Databases was performed to identify studies related to the use of the transradial approach for infra-aortic procedures. Meta-analysis was used to compare the transradial to the transfemoral route in terms of procedure success, complications, procedure parameters, and hospital length of stay. Results are presented as the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Nineteen studies containing 638 patients with transradial access for lower limb interventions were selected. Lesions were treated from the aortic bifurcation down to the popliteal artery. The mean technical success rate was 90.9%, conversion to a transfemoral approach was necessary in 9.9%, and complications were reported in 1.9%. The meta-analysis included 4 comparative studies involving 114 transradial and 208 transfemoral procedures. There was no significant advantage of either approach in terms of procedure success (OR 5.0, 95% CI 0.49 to 50.83, p=0.17), but the risk of developing a complication was significantly lower (OR 0.25, 95% CI 0.07 to 0.86, p=0.03) with the transradial approach.

CONCLUSION

Transradial access for lower limb endovascular interventions can be performed with comparable technical success and a lower overall complication profile compared to transfemoral access.

Application of an Adaptive Polynomial Chaos Expansion on Computationally Expensive Three-Dimensional Cardiovascular Models for Uncertainty Quantification and Sensitivity Analysis

When applying models to patient-specific situations, the impact of model input uncertainty on the model output uncertainty has to be assessed. Proper uncertainty quantification (UQ) and sensitivity analysis (SA) techniques are indispensable for this purpose. An efficient approach for UQ and SA is the generalized polynomial chaos expansion (gPCE) method, where model response is expanded into a finite series of polynomials that depend on the model input (i.e., a meta-model). However, because of the intrinsic high computational cost of three-dimensional (3D) cardiovascular models, performing the number of model evaluations required for the gPCE is often computationally prohibitively expensive. Recently, Blatman and Sudret (2010, “An Adaptive Algorithm to Build Up Sparse Polynomial Chaos Expansions for Stochastic Finite Element Analysis,” Probab. Eng. Mech., 25(2), pp. 183–197) introduced the adaptive sparse gPCE (agPCE) in the field of structural engineering. This approach reduces the computational cost with respect to the gPCE, by only including polynomials that significantly increase the meta-model’s quality. In this study, we demonstrate the agPCE by applying it to a 3D abdominal aortic aneurysm (AAA) wall mechanics model and a 3D model of flow through an arteriovenous fistula (AVF). The agPCE method was indeed able to perform UQ and SA at a significantly lower computational cost than the gPCE, while still retaining accurate results. Cost reductions ranged between 70–80% and 50–90% for the AAA and AVF model, respectively.

Towards individualized follow-up protocols after endovascular aortic aneurysm repair

Endovascular aneurysm repair (EVAR) has become the primary treatment option for elective abdominal aortic aneurysms. However, a significant number of patients require secondary interventions to maintain adequate aneurysm exclusion and ultimately prevent death from abdominal aortic aneurysm (AAA) rupture. To maintain success and offer timely secondary intervention, intensive image surveillance has been recommended. These rigorous surveillance regimens are costly and may have deleterious effects from radiation and contrast exposure. Improvements in patient selection, operative technique and devices have caused a decline in complications after EVAR. Therefore, there is a need to reduce surveillance after EVAR for patients at lower risk of complications and install individualized follow-up protocols. This review describes the current strategies for surveillance and clarification of risk factors and predictors for late complications and discusses proposed risk-adapted strategies for postoperative surveillance after EVAR.

A novel model of cryoinjury-induced myocardial infarction in the mouse: a comparison with coronary artery ligation

Mouse myocardial infarction (MI) models are frequently used research tools. The most commonly applied model is coronary artery ligation. However, coronary ligation often gives rise to apical aneurysmatic infarcts of variable size. Other infarct models include cryoinfarction, which produces reproducible infarcts of the anterior wall. Thus far, this model has not been extensively described in mice. Therefore, we developed a murine cryoinfarction model and compared it with coronary ligation. Studies were performed under isoflurane anesthesia with a follow-up of 4 and 8 wk. Cryoinfarction was induced using a 2- or 3-mm cryoprobe. Two-dimensional guided M-mode echocardiography was used to assess fractional shortening and left ventricular (LV) dimensions at baseline and end point. At end point, hemodynamics were assessed using a 1.4-Fr Millar catheter. Pressure-diameter relations were constructed by combining echocardiography and hemodynamic data. Histological and morphometric analyses of infarct and remote areas were performed. At 4 wk, 3-mm cryoinfarction resulted in decreased LV fractional shortening as well as decreased global LV contractility and relaxation, which was comparable with coronary ligation. No adverse remodeling was observed at this time point, in contrast with the ligation model. However, progressive LV remodeling occured between 4 and 8 wk after cryoinfarction with a further decline in hemodynamic parameters and LV pump function. Histologically, cryoinfarction resulted in highly reproducible, transmural, cone-shaped infarcts with reperfusion at the macrovascular level. These results indicate that the cryoinfarction model represents the anterior myocardial infarct with modest adverse remodeling and may thus be representative for infarcts encountered in clinical practice.

Functional expression of endothelial nitric oxide synthase fused to green fluorescent protein in transgenic mice

The activity of endothelial nitric oxide synthase (eNOS) is subject to complex transcriptional and post-translational regulation including the association with several proteins and variations in subcellular distribution. In the present study we describe a transgenic mouse model expressing eNOS fused to green fluorescent protein (GFP), which allows the study of localization and regulation of eNOS expression. We tested the functionality of eNOS in the eNOS-GFP mice. Expression of eNOS was restricted to the endothelial lining of blood vessels in various tissues tested, without appreciable expression in non-endothelial cells. Activity of the enzyme was confirmed by assaying the conversion of L-arginine to L-citrulline. NO production in isolated vessels was increased in transgenic mice when compared to non-transgenic control animals (4.88 +/- 0.59 and 2.48 +/- 0.47 micro mol/L NO, respectively, P < 0.005). Both the mean aortic pressure and the pulmonary artery pressure were reduced in eNOS-GFP mice (both approximately 30%, P < 0.05). Plasma cholesterol levels were also slightly reduced ( approximately 20%, P < 0.05). In conclusion, eNOS-GFP mice express functional eNOS and provide a unique model to study regulation of eNOS activity or eNOS-mediated vascular events, including response to ischemia, response to differences in shear stress, angiogenesis and vasculogenesis, and to study the subcellular distribution in relation with functional responses to these events.