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.

Role of Vascular Smooth Muscle Cell Phenotypic Switching and Calcification in Aortic Aneurysm Formation

Aortic aneurysm is a vascular disease whereby the ECM (extracellular matrix) of a blood vessel degenerates, leading to dilation and eventually vessel wall rupture. Recently, it was shown that calcification of the vessel wall is involved in both the initiation and progression of aneurysms. Changes in aortic wall structure that lead to aneurysm formation and vascular calcification are actively mediated by vascular smooth muscle cells. Vascular smooth muscle cells in a healthy vessel wall are termed contractile as they maintain vascular tone and remain quiescent. However, in pathological conditions they can dedifferentiate into a synthetic phenotype, whereby they secrete extracellular vesicles, proliferate, and migrate to repair injury. This process is called phenotypic switching and is often the first step in vascular pathology. Additionally, healthy vascular smooth muscle cells synthesize VKDPs (vitamin K-dependent proteins), which are involved in inhibition of vascular calcification. The metabolism of these proteins is known to be disrupted in vascular pathologies. In this review, we summarize the current literature on vascular smooth muscle cell phenotypic switching and vascular calcification in relation to aneurysm. Moreover, we address the role of vitamin K and VKDPs that are involved in vascular calcification and aneurysm. Visual Overview- An online visual overview is available for this article.

NADPH oxidase-derived overproduction of reactive oxygen species impairs postischemic neovascularization in mice with type 1 diabetes

We hypothesized that diabetes-induced oxidative stress may affect postischemic neovascularization. The response to unilateral femoral artery ligation was studied in wild-type or gp91(phox)-deficient control or type 1 diabetic mice or in animals treated with the anti-oxidant N-acetyl-l-cysteine (NAC) or with in vivo electrotransfer of a plasmid encoding dominant-negative Rac1 (50 microg) for 21 days. Postischemic neovascularization was reduced in diabetic mice in association with down-regulated vascular endothelial growth factor-A protein levels. In diabetic animals vascular endothelial growth factor levels and postischemic neovascularization were restored to nondiabetic levels by the scavenging of reactive oxygen species (ROS) by NAC administration or the inhibition of ROS generation by gp91(phox) deficiency or by administration of dominant-negative Rac1. Finally, diabetes reduced the ability of adherent bone marrow-derived mononuclear cells (BM-MNCs) to differentiate into endothelial progenitor cells. Treatment with NAC (3 mmol/L), apocynin (200 micromol/L), or the p38MAPK inhibitor LY333351 (10 micromol/L) up-regulated the number of endothelial progenitor cell colonies derived from diabetic BM-MNCs by 1.5-, 1.6-, and 1.5-fold, respectively (P < 0.05). In the ischemic hindlimb model, injection of diabetic BM-MNCs isolated from NAC-treated or gp91(phox)-deficient diabetic mice increased neovascularization by approximately 1.5-fold greater than untreated diabetic BM-MNCs (P < 0.05). Thus, inhibition of NADPH oxidase-derived ROS overproduction improves the angiogenic and vasculogenic processes and restores postischemic neovascularization in type 1 diabetic mice.

Reactive Oxygen-Forming Nox5 Links Vascular Smooth Muscle Cell Phenotypic Switching and Extracellular Vesicle-Mediated Vascular Calcification

RATIONALE

Vascular calcification, the formation of calcium phosphate crystals in the vessel wall, is mediated by vascular smooth muscle cells (VSMCs). However, the underlying molecular mechanisms remain elusive, precluding mechanism-based therapies.

OBJECTIVE

Phenotypic switching denotes a loss of contractile proteins and an increase in migration and proliferation, whereby VSMCs are termed synthetic. We examined how VSMC phenotypic switching influences vascular calcification and the possible role of the uniquely calcium-dependent reactive oxygen species (ROS)-forming Nox5 (NADPH oxidase 5).

METHODS AND RESULTS

In vitro cultures of synthetic VSMCs showed decreased expression of contractile markers CNN-1 (calponin 1), α-SMA (α-smooth muscle actin), and SM22-α (smooth muscle protein 22α) and an increase in synthetic marker S100A4 (S100 calcium binding protein A4) compared with contractile VSMCs. This was associated with increased calcification of synthetic cells in response to high extracellular Ca²⁺. Phenotypic switching was accompanied by increased levels of ROS and Ca²⁺-dependent Nox5 in synthetic VSMCs. Nox5 itself regulated VSMC phenotype as siRNA knockdown of Nox5 increased contractile marker expression and decreased calcification, while overexpression of Nox5 decreased contractile marker expression. ROS production in synthetic VSMCs was cytosolic Ca²⁺-dependent, in line with it being mediated by Nox5. Treatment of VSMCs with Ca²⁺ loaded extracellular vesicles (EVs) lead to an increase in cytosolic Ca²⁺. Inhibiting EV endocytosis with dynasore blocked the increase in cytosolic Ca²⁺ and VSMC calcification. Increased ROS production resulted in increased EV release and decreased phagocytosis by VSMCs.

CONCLUSIONS

We show here that contractile VSMCs are resistant to calcification and identify Nox5 as a key regulator of VSMC phenotypic switching. Additionally, we describe a new mechanism of Ca²⁺ uptake via EVs and show that Ca²⁺ induces ROS production in VSMCs via Nox5. ROS production is required for release of EVs, which promote calcification. Identifying molecular pathways that control Nox5 and VSMC-derived EVs provides potential targets to modulate vascular remodeling and calcification in the context of mineral imbalance. Graphic Abstract: A graphic abstract is available for this article.

Microparticles From Ischemic Muscle Promotes Postnatal Vasculogenesis

Background— We hypothesized that microparticles (MPs) released after ischemia are endogenous signals leading to postischemic vasculogenesis.

Methods and Results— MPs from mice ischemic hind-limb muscle were detected by electron microscopy 48 hours after unilateral femoral artery ligation as vesicles of 0.1- to 1-μm diameter. After isolation by sequential centrifugation, flow cytometry analyses showed that the annexin V + MP concentration was 3.5-fold higher in ischemic calves than control muscles (1392±406 versus 394±180 annexin V + MPs per 1 mg; P <0.001) and came mainly from endothelial cells (71% of MPs are CD 144+ ). MPs isolated from ischemic muscles induced more potent in vitro bone marrow–mononuclear cell (BM-MNC) differentiation into cells with endothelial phenotype than those isolated from control muscles. MPs isolated from atherosclerotic plaques were ineffective, whereas those isolated from apoptotic or interleukin-1β–activated endothelial cells also promoted BM-MNC differentiation. Interestingly, MPs from ischemic muscles produced more reactive oxygen species and expressed significantly higher levels of NADPH oxidase p47 (6-fold; P <0.05) and p67 subunits (16-fold; P <0.001) than controls, whereas gp91 subunit expression was unchanged. BM-MNC differentiation was reduced by 2-fold with MPs isolated from gp91-deficient animals compared with wild-type mice ( P <0.05). MP effects on postischemic revascularization were then examined in an ischemic hind-limb model. MPs isolated from ischemic muscles were injected into ischemic legs in parallel with venous injection of BM-MNCs. MPs increased the proangiogenic effect of BM-MNC transplantation, and this effect was blunted by gp91 deficiency. In parallel, BM-MNC proangiogenic potential also was reduced in ABCA1 knockout mice with impaired vesiculation.

Conclusion— MPs produced during tissue ischemia stimulate progenitor cell differentiation and subsequently promote postnatal neovascularization.

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.

Reduction of blood pressure, plasma cholesterol, and atherosclerosis by elevated endothelial nitric oxide

In the vascular system, nitric oxide is generated by endothelial NO synthase (eNOS). NO has pleiotropic effects, most of which are believed to be atheroprotective. Therefore, it has been argued that patients suffering from cardiovascular disease could benefit from an increase in eNOS activity. However, increased NO production can cause oxidative damage, cell toxicity, and apoptosis and hence could be atherogenic rather than beneficial. To study the in vivo effects of increased eNOS activity, we created transgenic mice overexpressing human eNOS. Aortic blood pressure was approximately 20 mm Hg lower in the transgenic mice compared with control mice because of lower systemic vascular resistance. The effects of eNOS overexpression on diet-induced atherosclerosis were studied in apolipoprotein E-deficient mice. Elevation of eNOS activity decreased blood pressure ( approximately 20 mm Hg) and plasma levels of cholesterol ( approximately 17%), resulting in a reduction in atherosclerotic lesions by 40%. We conclude that an increase in eNOS activity is beneficial and provides protection against atherosclerosis.

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.

Nicotine promotes vascular calcification via intracellular Ca2+-mediated, Nox5-induced oxidative stress and extracellular vesicle release in vascular smooth muscle cells

Aims

Smokers are at increased risk of cardiovascular events. However, the exact mechanisms through which smoking influences cardiovascular disease resulting in accelerated atherosclerosis and vascular calcification are unknown. The aim of this study was to investigate effects of nicotine on initiation of vascular smooth muscle cell (VSMC) calcification and to elucidate underlying mechanisms.

Methods and results

We assessed vascular calcification of 62 carotid lesions of both smoking and non-smoking patients using ex vivo micro-computed tomography (µCT) scanning. Calcification was present more often in carotid plaques of smokers (n = 22 of 30, 73.3%) compared to non-smokers (n = 11 of 32, 34.3%; P < 0.001), confirming higher atherosclerotic burden. The difference was particularly profound for microcalcifications, which was 17-fold higher in smokers compared to non-smokers. In vitro, nicotine-induced human primary VSMC calcification, and increased osteogenic gene expression (Runx2, Osx, BSP, and OPN) and extracellular vesicle (EV) secretion. The pro-calcifying effects of nicotine were mediated by Ca²⁺-dependent Nox5. SiRNA knock-down of Nox5 inhibited nicotine-induced EV release and calcification. Moreover, pre-treatment of hVSMCs with vitamin K2 ameliorated nicotine-induced intracellular oxidative stress, EV secretion, and calcification. Using nicotinic acetylcholine receptor (nAChR) blockers α-bungarotoxin and hexamethonium bromide, we found that the effects of nicotine on intracellular Ca²⁺ and oxidative stress were mediated by α7 and α3 nAChR. Finally, we showed that Nox5 expression was higher in carotid arteries of smokers and correlated with calcification levels in these vessels.

Conclusion

In this study, we provide evidence that nicotine induces Nox5-mediated pro-calcific processes as novel mechanism of increased atherosclerotic calcification. We identified that activation of α7 and α3 nAChR by nicotine increases intracellular Ca²⁺ and initiates calcification of hVSMCs through increased Nox5 activity, leading to oxidative stress-mediated EV release. Identifying the role of Nox5-induced oxidative stress opens novel avenues for diagnosis and treatment of smoking-induced cardiovascular disease.

Plasma Biomarkers to Predict Cardiovascular Outcome in Patients With Peripheral Artery Disease: A Systematic Review and Meta-Analysis

Supplemental Digital Content is available in the text.

Patients with lower extremity peripheral artery disease (PAD) are at increased risk of major adverse cardiovascular events. Numerous plasma biomarkers have been investigated in lower extremity PAD, but none are used for clinical risk assessment. We aimed to provide a comprehensive overview of biomarker testing in PAD as a first step to improve risk stratification.

Endothelial nitric oxide synthase activity is essential for vasodilation during blood flow recovery but not for arteriogenesis

OBJECTIVE

Arteriogenesis is the major mechanism of vascular growth, which is able to compensate for blood flow deficiency after arterial occlusion. Endothelial nitric oxide synthase (eNOS) activity is essential for neovascularization, however its specific role in arteriogenesis remains unclear. We studied the role of eNOS in arteriogenesis using 3 mouse strains with different eNOS expression.

METHODS AND RESULTS

Distal femoral artery ligation was performed in eNOS-overexpressing mice (eNOStg), eNOS-deficient (eNOS-/-) mice, and wild type (WT) controls. Tissue perfusion and collateral-dependent blood flow were significantly increased in eNOStg mice compared with WT only immediately after ligation. In eNOS-/- mice, although tissue perfusion remained significantly decreased, collateral-dependent blood flow was only decreased until day 7, suggesting normal, perhaps delayed collateral growth. Histology confirmed no differences in collateral arteries of eNOStg, eNOS-/-, and WT mice at 1 and 3 weeks. Administration of an NO donor induced vasodilation in collateral arteries of eNOS-/- mice, but not in WT, identifying the inability to vasodilate collateral arteries as main cause of impaired blood flow recovery in eNOS-/- mice.

CONCLUSIONS

This study demonstrates that eNOS activity is crucial for NO-mediated vasodilation of peripheral collateral vessels after arterial occlusion but not for collateral artery growth.

Hypertension impairs postnatal vasculogenesis: role of antihypertensive agents

We analyzed the effect of hypertension on postischemic vasculogenesis. Ischemia was induced by right femoral artery ligature in Wistar Kyoto rats (WKY) or spontaneously hypertensive rats (SHR) treated with or without angiotensin-converting enzyme inhibitor (Perindopril, 0.76 mg/kg/d) and angiotensin type 1 receptor blocker (losartan, 30 mg/kg/d). Basal postischemic neovascularization was reduced in SHR compared to WKY (P<0.05, n=8). Treatment with ACE inhibitor or angiotensin type 1 receptor blocker decreased blood pressure levels by 1.4- and 1.3-fold (P<0.001), respectively and restored vessel growth in SHR to WKY levels. Interestingly, 14 days after bone-marrow mononuclear cell (BM-MNC) transfusion, angiographic scores, capillary density, and foot perfusion were decreased by 1.4-, 1.5-, and 1.2-fold, respectively in SHR transfused with BM-MNCs isolated from SHR compared to those receiving BM-MNCs of WKY (P<0.05, n=6). Alteration in BM-MNCs proangiogenic potential was likely related to the reduction in their ability to mobilize into peripheral circulation, as revealed by the 2.9-fold decrease in number of circulating CD34+/CD117+ cells (P<0.001) and to differentiate into cells with endothelial phenotype, as revealed by the 2.1-fold reduction in percentages of DilLDL/BS-1 lectin positive cells (P<0.001). In addition, reactive oxygen species (ROS) levels were increased by 2.2-fold in SHR BM-MNCs compared to WKY BM-MNCs (P<0.01), as assessed by L-012 luminescence. Cotreatment with ACE inhibitor, angiotensin type 1 receptor blocker, or antioxidants (NAC 3 mmol/L, Apocynin 200 micromol/L) reduced ROS levels, improved the number of DilLDL/BS-1 lectin-positive cells by around 1.5-fold, and restored BM-MNCs proangiogenic effects in ischemic hindlimb. In conclusion, alteration in progenitor cell proangiogenic function may participate to the hypertension-induced impairment in postischemic revascularization.

High Pressure Promotes Monocyte Adhesion to the Vascular Wall

Hypertension is a known risk factor for the development of atherosclerosis. To assess how mechanical factors contribute to this process, mouse carotid arteries were maintained in organ culture at normal (80 mm Hg) or high (150 mm Hg) intraluminal pressure for 1, 6, 12, or 24 hours. Thereafter, fluorescent human monocytic cells (U937) were injected intraluminally and allowed to adhere for 30 minutes before washout. U937 adhesion was increased in vessels kept at 150 mm Hg 12 hours (23.5+/-5.7 versus 9.9+/-2.2 cells/mm at 80 mm Hg; P<0.05) or 24 hours (26.7+/-5.7 versus 8.8+/-1.5 cells/mm; P<0.05). At 24 hours, high pressure was associated with increased mRNA expression of monocyte chemoattractant protein-1, interleukin-6, keratinocyte-derived chemokine, and vascular cell adhesion molecule-1 (6.9+/-2.1, 4.4+/-0.1, 9.8+/-2.8, and 2.4+/-0.1-fold respectively; P<0.05), as assessed by quantitative RT-PCR and corroborated by immunohistochemistry, which also revealed an increase in intracellular adhesion molecule-1 expression. Nuclear factor kappaB inhibition using SN50 peptide abolished the overexpression of chemokines and adhesion molecules and reduced U937 adhesion in vessels at 150 mm Hg. Moreover, treatment of vessels and cells with specific neutralizing antibodies established that monocyte chemoattractant protein-1, interleukin-6, and keratinocyte-derived chemokine released from vessels at 150 mm Hg primed the monocytes, increasing their adhesion to vascular cell adhesion molecule-1 but not intracellular adhesion molecule-1 via alpha4beta1 integrins. The additive effect of chemokines on the adhesion of U937 cells to vascular cell adhesion molecule-1 was confirmed by in vitro assay. Finally, pressure-dependent U937 adhesion was blunted in arteries from mice overexpressing endothelial NO synthase. Hence, high intraluminal pressure induces cytokine and adhesion molecule expression via nuclear factor kappaB, leading to monocytic cell adhesion. These results indicate that hypertension may directly contribute to the development of atherosclerosis through nuclear factor kappaB induction.

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.

Combination of the angiotensin-converting enzyme inhibitor perindopril and the diuretic indapamide activate postnatal vasculogenesis in spontaneously hypertensive rats

Cardiovascular risk factors are associated with reduction in both the number and function of vascular progenitor cells. We hypothesized that 1) hypertension abrogates postnatal vasculogenesis, and 2) antihypertensive treatment based on the combination of perindopril (angiotensin-converting enzyme inhibitor) and indapamide (diuretic) may counteract hypertension-induced alteration in progenitor cell-related effects. Postischemic neovascularization was significantly lower in untreated spontaneously hypertensive rats (SHRs) compared with Wistar Kyoto (WKY) rats (p < 0.05). Treatment of SHRs with perindopril and the combination of perindopril/indapamide reduced the blood pressure levels and normalized vessel growth in ischemic area. Cotreatment with perindopril and indapamide increased vascular endothelial growth factor and endothelial nitric-oxide synthase protein contents, two key proangiogenic factors. It is interesting to note that 14 days after bone marrow mononuclear cell (BM-MNC) transplantation, revascularization was significantly lower in ischemic SHRs receiving BM-MNCs isolated from SHRs compared with those receiving BM-MNCs isolated from WKY rats (p < 0.05). Alteration in proangiogenic potential of SHR BM-MNCs was probably related to the reduction in their ability to differentiate into endothelial progenitor cells in vitro. Furthermore, the number of circulating endothelial progenitor cells (EPCs) was reduced by 3.1-fold in SHRs compared with WKY rats (p < 0.001). Treatments with perindopril or perindopril/indapamide restored the ability of BM-MNCs to differentiate in vitro into EPCs, increased the number of circulating EPCs, and re-established BM-MNC proangiogenic effects. Therefore, hypertension is associated with a decrease in the number of circulating progenitor cells and in the BM-MNC proangiogenic potential, probably leading to vascular complications in this setting. The combination of perindopril and indapamide counteracts hypertension-induced alterations in progenitor cell-related effects and restores blood vessel growth.

Surgical management of haemorrhaging renal angiomyolipoma in pregnancy

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We report the case of a 25-week pregnant woman that had a ruptured AML.

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This is the first case of nephrectomy in late second trimester with the foetus left in-utero.

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We present a literature review of the management of bleeding AML in pregnancy.

Introduction

Renal angiomyolipoma (AML) is a benign mesenchymal tumour of the kidney with a tendency of aneurysm formation at risk of rupturing. Due to increased maternal circulation and hormonal influences, rupture risk is greater in pregnancy, often leading to a vascular emergency and premature delivery or termination.

Presentation of case

A 24-weeks pregnant woman (45 years old, G6P1) presented with haematuria and flank pain. CT showed AML with acute haemorrhage. The patient became haemodynamically unstable and underwent urgent embolisation and follow-on total radical nephrectomy with the foetus being left in-utero. This involved a multidisciplinary team (urologist, vascular surgeon, interventional radiologist and obstetrician). The procedure was uncomplicated and the pregnancy went to term with a healthy girl delivered at 38 weeks.

Discussion

The incidence of AML is 0.13% in the general population. 21 reports of haemorrhaging AML in pregnancy have been published in the last 35 years. Mean gestational age was 29.6 weeks. Eight were treated conservatively to term, one underwent exploratory laparotomy with evacuation of haematoma only, five were embolised, and seven were managed with nephrectomy. Of the nephrectomy subgroup, one was preceded by vaginal delivery and five underwent concurrent caesarean section (one with pre-op embolisation). There were two associated foetal deaths.

Conclusion

This case demonstrates that with a multidisciplinary approach, it is possible to successfully leave a foetus undelivered whilst performing a radical nephrectomy for a large bleeding AML in a woman carrying a late second trimester pregnancy.

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.

Tetrapeptide AcSDKP Induces Postischemic Neovascularization Through Monocyte Chemoattractant Protein-1 Signaling

BACKGROUND

We investigated the putative proangiogenic activity and molecular pathway(s) of the tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) in a model of surgically induced hindlimb ischemia.

METHODS AND RESULTS

Hindlimb ischemia was induced by femoral artery ligature and an osmotic minipump was implanted subcutaneously to deliver low (0.12 mg/kg per day) or high (1.2 mg/kg per day) doses of AcSDKP, for 7 or 21 days. Angiography scores, arteriole density, capillary number, and foot perfusion were increased at day 21 in the high-dose AcSDKP-treated mice (by 1.9-, 1.8-, 1.3-, and 1.6-fold, respectively) compared with control animals (P<0.05, P<0.01, P<0.01, respectively). AcSDKP treatment for 24 hours upregulated the monocyte chemoattractant protein-1 (MCP-1) mRNA and protein levels by 1.5-fold in cultured endothelial cells (P<0.01). In the ischemic hindlimb model, administration of AcSDKP also enhanced MCP-1 mRNA levels by 90-fold in ischemic leg (P<0.001) and MCP-1 plasma levels by 3-fold (P<0.001 versus untreated ischemic control mice). MCP-1 levels upregulation were associated with a 2.3-fold increase in the number of Mac3-positive cells in ischemic area of AcSDKP-treated mice (P<0.001 versus untreated animals). Interestingly, AcSDKP-induced monocyte/macrophage infiltration and postischemic neovascularization was fully blunted in MCP-1-deficient animals.

CONCLUSIONS

AcSDKP stimulates postischemic neovascularization through activation of a proinflammatory MCP-1-related pathway.

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.