Systematic Review and Meta-analysis of Fenestrated and Chimney/Snorkel Techniques for Endovascular Repair of Juxtarenal Aortic Aneurysms.

OBJECTIVES: Comparative effectiveness of fenestrated endovascular aneurysm repair (FEVAR) and chimney graft endovascular aneurysm repair (ChEVAR) for juxtarenal aortic aneurysms (JAAs) remains unclear. Our objective was to identify and analyze the current body of evidence comparing the effectiveness of both techniques for JAA. METHODS: We performed a systematic review and meta-analysis comparing the effectiveness of FEVAR and ChEVAR for JAA repair. We searched MEDLINE, EMBASE, and Cochrane Register for Controlled Trials from January 1, 1990, for randomized and non-randomized studies assessing outcomes of FEVAR and ChEVAR for JAA repair. Screening, data extraction, risk of bias assessment, and GRADE (Grading of Recommendations, Assessments, Development, and Evaluations) certainty of evidence were performed in duplicate. Data were pooled statistically where possible. RESULTS: Nine retrospective cohort studies comparing the use of FEVAR and ChEVAR for juxtarenal aneurysm were included for meta-analysis. The FEVAR and ChEVAR arms of the meta-analysis consisted of 726 participants and 518 participants, respectively. There were 598 (86.8%) and 332 (81.6%) men in each arm. The mean diameter was larger in the ChEVAR arm (59 mm vs 52.5 mm). Both techniques had similar rates of postoperative 30-day mortality, 3.38% (8/237) versus 3.52% (8/227), acute kidney injury, 16.76% (31/185) versus 17.31% (18/104), and major adverse cardiac events, 7.30% (46/630) versus 6.60% (22/333). The meta-analysis supported the use of FEVAR for most outcomes, with significant advantage for technical success (odds ratio [OR]: 3.24, 95% CI: 1.24-8.42) and avoidance of type 1 endoleak (OR: 5.76, 95% CI: 1.94-17.08), but a disadvantage for spinal cord ischemia (OR: 10.21, 95% CI: 1.21-86.11), which had a very low number of events. The quality of evidence was "moderate" for most outcomes. CONCLUSION: Both endovascular techniques had good safety profiles. The evidence does not support superiority of either FEVAR or ChEVAR for JAA. CLINICAL IMPACT: While lack of equipoise has hampered the design of randomised trials of open versus endovascular repair of juxtarenal aortic aneurysms, concern about the durability of endovascular repair highlights the need for stronger evidence of the comparative efficacy of endovascular techniques. This review performed meta-analysis and evidence appraisal of recent data from large observational studies comparing fenestrated and chimney techniques, using a comprehensive outcome set. Superiority of either intervention could not be established due to differences in participants' baseline risk in each study arm. However, data suggests that both techniques are safe and suitable for use when indicated.

Application of Novosorb biodegradable temporising matrix in wounds of different aetiologies: a case series.

DECLARATION OF INTEREST: The authors have no conflicts of interest to declare.

Effect of Pseudomonas colonisation on lower limb venous ulcer healing: a systematic review.

OBJECTIVE: Pseudomonas aeruginosa is a Gram-negative bacillus that commonly colonises lower limb venous ulcers. Its effects on venous ulcer healing are widely debated. It produces exotoxins and elastase, as well as forming biofilms in hard-to-heal wounds. It is postulated that these virulence factors lead to slower healing times in patients with lower limb venous ulcers colonised with Pseudomonas. This review aimed to summarise the available evidence pertaining to this topic. METHOD: A systematic review was performed in August 2019, where the Pubmed, Cochrane and Embase databases were searched for relevant literature according to PRISMA guidelines. Retrospective and prospective studies examining the effect of Pseudomonas colonisation on any measure of ulcer healing were included. RESULTS: Some 282 articles were screened, of which seven studies including 491 patients were ultimately included for analysis. Of these, no study demonstrated a significant association between Pseudomonas colonisation and delayed healing of venous ulcers. In five of the seven studies, the effect of Pseudomonas aeruginosa on initial ulcer size at presentation was recorded. CONCLUSION: All the studies demonstrated an association between ulcer size and the presence of Pseudomonas aeruginosa. While Pseudomonas aeruginosa may colonise larger ulcers or those with a worse prognosis, no evidence was found to support the hypothesis that this colonisation had a negative impact on lower limb venous ulcer healing.

Correlating Ex Vivo Carotid Calcification Measurements With Cerebrovascular Symptoms: A Proof-of-Concept Study.

BACKGROUND AND PURPOSE: The purpose of this study is to examine the ability of ex vivo derived Agatston, Volume, and Density-Volume calcium scores or calcium density measurements to differentiate between carotid plaques based on preoperative cerebrovascular symptomatology. METHODS: Thirty-eight carotid plaques were acquired from standard endarterectomy. Micro-computed tomography was performed on the ex vivo samples. Image series were downsampled to represent the resolution of clinical multidetector computed tomography. Agatston, Volume, and Density-Volume carotid calcium scores were then calculated using coronary methodologies. The fractions of low- and high-density calcification were also determined. RESULTS: The coronary calcium scores could not differentiate between carotid plaques from asymptomatic versus symptomatic patients. However, plaques from asymptomatic patients contained significantly lower fractions of low-density calcification and higher fractions of high-density calcification. CONCLUSIONS: Screening for carotid calcium density in noncontrast computed tomography could reflect plaque stability.

On the influence of wall calcification and intraluminal thrombus on prediction of abdominal aortic aneurysm rupture.

OBJECTIVE: Parameters other than maximum diameter that predict rupture of abdominal aortic aneurysms (AAAs) may be helpful for risk-benefit analysis in individual patients. The aim of this study was to characterize the biomechanical-structural characteristics associated with AAA walls to better identify the related mechanistic variables required for an accurate prediction of rupture risk. METHODS: Anterior AAA wall (n = 40) and intraluminal thrombus (ILT; n = 114) samples were acquired from 18 patients undergoing open surgical repair. Biomechanical characterization was performed using controlled circumferential stretching tests combined with a speckle-strain tracking technique to quantify the spatial heterogeneity in deformation and localized strains in the AAA walls containing calcification. After mechanical testing, the accompanying microstructural characteristics of the AAA wall and ILT types were examined using electron microscopy. RESULTS: No significant correlation was found between the AAA diameter and the wall mechanical properties in terms of Cauchy stress (rs = -0.139; P = .596) or stiffness (rs = -0.451; P = .069). Quantification of significant localized peak strains, which were concentrated in the tissue regions surrounding calcification, reveals that peak strains increased by a mean of 174% as a result of calcification and corresponding peak stresses by 18.2%. Four ILT types characteristic of diverse stages in the evolving tissue microstructure were directly associated with distinct mechanical stiffness properties of the ILT and underlying AAA wall. ILT types were independent of geometric factors, including ILT volume and AAA diameter measures (ILT stiffness and AAA diameter [rs = -0.511; P = .074]; ILT stiffness and ILT volume [rs = -0.245; P = .467]). CONCLUSIONS: AAA wall stiffness properties are controlled by the load-bearing capacity of the noncalcified tissue portion, and low stiffness properties represent a highly degraded vulnerable wall. The presence of calcification that is contiguous with the inner wall causes severe tissue overstretching in surrounding tissue areas. The results highlight the use of additional biomechanical measures, detailing the biomechanical-structural characteristics of AAA tissue, that may be a helpful adjunct to improve the accuracy of rupture prediction.

Microindentation of fresh soft biological tissue: A rapid tissue sectioning and mounting protocol.

Microindentation of fresh biological tissues is necessary for the creation of 3D biomimetic models that accurately represent the native extracellular matrix microenvironment. However, tissue must first be precisely sectioned into slices. Challenges exist in the preparation of fresh tissue slices, as they can tear easily and must be processed rapidly in order to mitigate tissue degradation. In this study, we propose an optimised mounting condition for microindentation and demonstrate that embedding tissue in a mixture of 2.5% agarose and 1.5% gelatin is the most favourable method of tissue slice mounting for microindentation. This protocol allows for rapid processing of fresh biological tissue and is applicable to a variety of tissue types.

Outcomes of Acute Limb Ischaemia in Patients with Underlying Malignancy: A Systematic Review.

OBJECTIVE: Previous studies have demonstrated amputation and mortality rates to be 14.3% - 30% and 11.4% - 28.9%, respectively, for all patients presenting with acute limb ischaemia (ALI). Rates of ALI are higher in patients with malignancy than in those without. Despite this, there remains uncertainty with regards to the most appropriate management for patients with cancer presenting with ALI. This is because of previously published high rates of associated morbidity and mortality in this population. The aim of this review was to summarise the available evidence reporting on outcomes of ALI in patients with underlying malignancy. METHOD: A systematic review was performed in August 2020 in accordance with the PRISMA guidelines. The Medline, Scopus, Cochrane, and Embase databases were searched with the following search string ((acute limb ischaemia) OR (acute limb ischemia)) AND ((cancer) OR (malignancy)). A total of 849 papers were identified and reviewed; six studies were included. Studies were assessed for bias using the National Institute of Health/National Heart, Lung and Blood Institute Quality Assessment Tool. Data including demographics, Rutherford classification, baseline performance scores, method of revascularisation, and peri-procedural outcomes were extracted and analysed. Data were pooled based on outcomes of interest and pooled prevalence was reported with 95% confidence intervals (CI). RESULTS: Six studies with 284 patients with cancer were included for analysis. The pooled overall risk of amputation was 15% (95% CI 5.9 - 26.9). The pooled 30 day mortality rate was 24% (95% CI 14.7 - 34.6). CONCLUSION: Despite limitations of interstudy selection bias and some clinical heterogeneity, the included studies demonstrated acceptable short and medium term outcomes for patients with cancer undergoing revascularisation for acute limb ischaemia. This is in line with current recommendations that patients with underlying malignancy should be considered strongly for revascularisation.

Open repair of a type II endoleak facilitated by temporary disconnection of graft components.

Endoleaks are a frequent indication for reintervention after endovascular repair of an abdominal aortic aneurysm. Here we present a method of open repair of a persistent type II endoleak involving graft component separation and reconstruction, in a patient with symptomatic interval aneurysmal sac enlargement despite endovascular coiling and embolization. This case report demonstrates an alternative open technique of endograft component separation and reconstruction that may be required in cases where open repair with sac exploration and vessel oversewing is hindered by the graft position.

An international experience of electronic communication and implementation of eHealth solutions in a vascular surgery clinic.

INTRODUCTION: Communication is key to any successful relationship with the patient-physician partnership being no different. Recent advances in technology have provided us with an array of new communication tools such as the mobile phone, computer, internet, and email. This new technology has revolutionized communications; however, limitations to their widespread use include access, literacy, and willingness for both the physician and patient to change. METHODS: To gather international data, questionnaires were completed by patients attending vascular surgery outpatient clinics in hospitals in Ireland and Canada. RESULTS: Five hundred ninety-seven patients participated in the study. Of the participants, 83.2% were over 50 years old. The mean age was 63.1 years, with a range of 18-95 years. Overall, home phone call was the most preferred method of communication with 41.0% of patients selecting this option. Of the patients, 82.4% had a mobile phone but just 48.5% use text message. In those over the age of 70, 72.1% use a mobile phone and just 25.3% use text message. Of the participants, 64.1% had access to a computer, and 67.2% had access to the internet with a decline in the usage of both with increasing age. DISCUSSION: Within this patient population, the use of technologies decreases with increasing age of the patients. This demonstrates a large population of service users who are contented with conventional methods of communication. Change within healthcare ICT is inevitable, and therefore, these patients need to be guided and educated to allow a smooth transition from the old to the new.

Contrast-induced nephrotoxicity: possible synergistic effect of stress hyperglycemia.

OBJECTIVE: Oxidative stress on the renal tubules has been implicated as a mechanism of injury in both stress hyperglycemia and contrast-induced nephrotoxicity. The purpose of this study was to determine whether the combination of these effects has a synergistic effect on accentuating renal tubular apoptosis and therefore increasing the risk of contrast-induced nephrotoxicity. MATERIALS AND METHODS: Dog kidney cells were incubated with 5- and 30-mmol/L glucose solutions and no glucose and then exposed for 2 hours to three types of contrast media-high osmolar (370 mg I/mL), low osmolar (300 mg I/mL), and isoosmolar (320 mg I/mL)-and a mannitol control solution. In an identical experiment, each group of cells was pretreated with an antioxidant-N-acetylcysteine or taurine-to evaluate the protective effect, if any. Apoptosis was assessed with fluorescence-activated cell sorter flow cytometry. RESULTS: The high-osmolar contrast medium was associated with significantly elevated levels of apoptosis compared with the mannitol control (percentage apoptosis, 27.98 +/- 1.08 vs 6.19 +/- 0.771; p < 0.001). This effect was less pronounced after incubation with the low-osmolar agent but was still significant (percentage apoptosis, 20.19 +/- 0.3665 vs 6.19 +/- 0.771; p < 0.001). The isosmolar agent did not have a significant effect. Both the high- and low-osmolar contrast media coupled with hyperglycemia (30-mmol/L glucose) were associated with a significantly increased level of apoptosis. In all contrast medium groups, taurine had a greater protective effect on attenuation of cell apoptosis than did N-acetylcysteine. CONCLUSION: The combination of contrast medium and an elevated glucose level has a synergistic effect on apoptosis. Taurine may be a more effective prophylactic antioxidant than the currently advocated antioxidant, N-acetylcysteine.

Iodinated contrast media alter immune responses in pro-inflammatory states.

BACKGROUND: Hypertonic saline causes a transient elevation of blood osmolality and has been shown to alter cellular inflammatory responses in pro-inflammatory states. Intravascular administration of iodine contrast media also causes a transient elevation of blood osmolarity. PURPOSE: To investigate the effect of iodine contrast media on leukocyte-endothelial interaction in vivo using intravital microscopy. MATERIAL AND METHODS: Male Sprague-Dawley rats (n=36) were randomized into six groups and were treated with: saline, high osmolar contrast medium, low osmolar contrast medium, and endotoxin alone and in combination with the high and low osmolar contrast media. The effect on leukocyte-endothelial interaction in the post-mesenteric venules was observed using the technique of intravital microscopy. The sequence of leukocyte rolling velocity, leukocyte-endothelial cell adherence, and transmigration was recorded and analyzed at 10 min intervals to a maximum of 120 min. RESULTS: Endotoxin significantly decreased the rolling velocity and increased the adherence and transmigration of leukocytes in a time-dependent manner. Both types of iodine contrast media attenuated this pro-inflammatory response to endotoxin. This effect began between 60 and 70 min after the onset of the experiment. CONCLUSION: Hyperosmolar and lower osmolar iodine contrast media attenuate the pro-inflammatory leukocyte-endothelial response to endotoxin in vivo.

Hybrid covered endovascular reconstruction of the aortic bifurcation (CERAB) procedure is preferable to aortobifemoral bypass for limb-threatening aortoiliac occlusive disease during the COVID-19 crisis.

The COVID-19 pandemic is disrupting the provision of acute vascular surgery across the globe. Limited evidence of the impact of nosocomial infection on patient outcomes as well as concerns about critical care capacity will likely have an impact on surgical decision-making. Endovascular therapy offers a way by which perioperative risk can be reduced for vascular patients while also reducing the impact of acute surgery on intensive care unit capacity. This case report describes the management of a patient with complex aortoiliac occlusive disease by a hybrid endovascular approach in light of these constraints, with a successful outcome.

Comparative analysis of calcification parameters with Agatston Score approximations for ex vivo atherosclerotic lesions.

BACKGROUND: The Agatston Calcium Score is a predictor of major adverse cardiovascular events but it is unable to identify high-risk lesions. Recent research suggests that examining calcification phenotype could be more indicative of plaque stability. OBJECTIVE: To examine the Agatston score's ability to determine atherosclerotic calcification phenotype. METHODS: Micro-Computed Tomography was performed on 20 carotid and 20 peripheral lower limb lesions. ImageJ pixel histogram analysis quantified the non-calcified (≥30HU, <130HU) and calcified (≥130HU) tissue volumes. ImageJ '3D Objects Counter' plugin determined the calcified particle count, volumes and maximum attenuation density of each particle. Image stacks were subsequently downsampled to a resolution of 0.7 × 0.7 × 3 mm and an approximation for the Extra-Coronary Calcium Scores (ECCS) were calculated. Spearman's correlation examined the relationships between ECCS approximations and calcification parameters. RESULTS: ECCS has a strong positive correlation with the Calcified Volume Fraction (CVF) (rs = 0.865, p < 0.0005), weak positive correlations with Calcified Particle Fraction (CPF) (rs = 0.422, p = 0.007) and Microcalcification Fraction (micro-CF) (rs = 0.361, p = 0.022). There is no correlation evident between ECCS and Calcified Particle Index (CPI) (rs = -0.162, p = 0.318). It is apparent that there is a high prevalence of microcalcifications in both carotid and peripheral lower limb lesions. Additionally, an inverse relationship exists between calcified particle volume and maximum-recorded attenuation density. CONCLUSION: The density-weighted Agatston calcium scoring methodology needs to be reviewed. Calcium scoring which differentiates between critical calcification morphologies, rather than presenting a density-weighted score, is required to direct high-risk plaques towards tailored treatment.

Relating the mechanical properties of atherosclerotic calcification to radiographic density: A nanoindentation approach.

Calcification morphology can determine atherosclerotic plaque stability and is associated with increased failures rates for endovascular interventions. Computational efforts have sought to elucidate the relationship between calcification and plaque rupture in addition to predicting tissue response during aggressive revascularisation techniques. However, calcified material properties are currently estimated and may not reflect real tissue conditions. The objective of this study is to correlate calcification mechanical properties with three radiographic density groups obtained from corresponding Computed Tomography (CT) images. Seventeen human plaques extracted from carotid (n = 10) and peripheral lower limb (n = 7) arteries were examined using micro-computed tomography (µCT), simultaneously locating the calcified deposits within their internal structure and quantifying their densities. Three radiographic density groups were defined based on the sample density distribution: (A) 130-299.99 Hounsfield Units (HU), (B) 300-449.99 HU and (C) >450 HU. Nanoindentation was employed to determine the Elastic Modulus (E) and Hardness (H) values within the three density groups. Results reveal a clear distinction between mechanical properties with respect to radiographic density groups (p < 0.0005). No significant differences exist in the density-specific behaviours observed between carotid and peripheral samples. Previously defined calcification classifications indicate an association with specific radiographic density patterns. Scanning Electron Microscopy (SEM) examination revealed that density group A regions consist of both calcified and non-calcified tissues. Further research is required to define the radiographic thresholds which identify varying degrees of tissue calcification. This study demonstrates that the mechanical properties of fully mineralised atherosclerotic calcification emulate that of bone tissues (17-25 GPa), affording computational models with accurate material parameters. STATEMENT OF SIGNIFICANCE: Global mechanical characterisation techniques disregard the heterogeneous nature of atherosclerotic lesions. Previous nanoindentation results for carotid calcifications have displayed a wide range. This study evaluates calcification properties with respect to radiographic density obtained from Micro-CT images. This is the first work to characterise calcifications from peripheral lower limb arteries using nanoindentation. Results demonstrate a strong positive correlation between radiographic density and calcification mechanical properties. Characterising calcifications using their density values provides clarity on the variation in published properties for calcified tissues. Furthermore, this study confirms the hypothesis that fully calcified plaque tissue behaviour similar to that of bone. Appropriate material parameters for calcified tissues can now be employed in computational simulations.

Two weeks taurine supplementation reverses endothelial dysfunction in young male type 1 diabetics.

Type 1 diabetics have a well-recognised risk of accelerated cardiovascular disease. Even in the absence of clinical signs there are detectable abnormalities of conduit vessel function. Our group has previously reported reversal of endothelial dysfunction in diabetics with pravastatin. In young asymptomatic smokers, taurine supplementation has a beneficial impact on macrovascular function, assessed by FMD, and shows an up-regulation of nitric oxide from monocyte-endothelial cell interactions. We hypothesise that taurine supplementation reverses early endothelial abnormalities in young male type 1 diabetics, as assessed by applanation tonometry, brachial artery ultrasound and laser Doppler fluximetry. Asymptomatic, male diabetics (n=9) were scanned prior to treatment and then randomised in a double-blind cross-over fashion to receive either 2 weeks placebo or taurine. Control patients (n=10) underwent a baseline scan. Assessed diabetics had detectable, statistically significant abnormalities when compared with controls, in both arterial stiffness (augmentation index) and brachial artery reactivity (FMD). Both of these parameters were returned to control levels with 2 weeks taurine supplementation. In conclusion, 2 weeks taurine supplementation reverses early, detectable conduit vessel abnormalities in young male diabetics. This may have important implications in the long-term treatment of diabetic patients and their subsequent progression towards atherosclerotic disease.

Aortic plaque rupture in the setting of acute lower limb ischemia.

Acute aortic plaque rupture is an uncommon cause of acute lower limb ischemia. The authors report sequence computed tomographic imaging of a distal aortic plaque rupture in a young man with bilateral lower limb complications. Clinical awareness, prompt recognition and imaging, and appropriate treatment of this uncommon condition are necessary to improve patient outcomes.