Asymptomatic Abdominal Aortic Aneurysm Research Articles

Editor's Choice – External Validation of a Prognostic Model for Survival of Patients With Abdominal Aortic Aneurysms Treated by Endovascular Aneurysm Repair

Current guidelines recommend diameter monitoring of small and asymptomatic abdominal aortic aneurysms (AAAs) due to the low risk of rupture. Elective AAA repair is recommended for diameters ≥ 5.5 cm in men and ≥ 5.0 cm in women. However, data supporting the efficacy of elective treatment for all patients above these thresholds are diverging. For a subgroup of patients, life expectancy might be very short, and elective AAA repair at the current threshold may not be justified. This study aimed to externally validate a predictive model for survival of patients with asymptomatic AAA treated with endovascular aneurysm repair (EVAR). This was a multicentre international retrospective observational cohort study. Data were collected from four European aortic centres treating patients between 2001 and 2021. The initial model included age, estimated glomerular filtration rate (eGFR), and chronic obstructive pulmonary disease (COPD) as independent predictors for survival. Model performance was measured by discrimination and calibration. The validation cohort included 1 500 patients with a median follow up of 65 months, during which 54.6% of the patients died. The external validation showed slightly decreased discrimination ability and signs of overfitting in model calibration. However, a high risk subgroup of patients with impaired survival rates was identified: octogenarians with eGFR < 60 OR COPD, septuagenarians with eGFR < 30, and septuagenarians with eGFR < 60 and COPD having survival rates of only 55.2% and 15.5% at five and 10 years, respectively. EVAR is a valuable treatment option for AAA, especially for patients unsuitable for open repair. Nonetheless, not all these patients will benefit from EVAR, and an individualised treatment recommendation should include considerations on life expectancy. This study provides a risk stratification to identify patients who may not benefit from EVAR under the present diameter threshold.

Measurement of Abdominal Aortic Aneurysm Strain Using MR Deformable Image Registration: Accuracy and Relationship to Recent Aneurysm Progression.

Management of asymptomatic abdominal aortic aneurysm (AAA) based on maximum aneurysm diameter and growth rate fails to preempt many ruptures. Assessment of aortic wall biomechanical properties may improve assessment of progression and rupture risk. This study aimed to assess the accuracy of AAA wall strain measured by cine magnetic resonance imaging (MRI) deformable image registration (MR strain) and investigate its relationship with recent AAA progression. The MR strain accuracy was evaluated in silico against ground truth strain in 54 synthetic MRIs generated from a finite element model simulation of an AAA patient's abdomen for different aortic pulse pressures, tissue motions, signal intensity variations, and image noise. Evaluation included bias with 95% confidence interval (CI) and correlation analysis. Association of MR strain with AAA growth rate was assessed in 25 consecutive patients with >6 months of prior surveillance, for whom cine balanced steady-state free-precession imaging was acquired at the level of the AAA as well as the proximal, normal-caliber aorta. Univariate and multivariate regressions were used to associate growth rate with clinical variables, maximum AAA diameter (Dmax), and peak circumferential MR strain through the cardiac cycle. The MR strain interoperator variability was assessed using bias with 95% CI, intraclass correlation coefficient, and coefficient of variation. In silico experiments revealed an MR strain bias of 0.48% ± 0.42% and a slope of correlation to ground truth strain of 0.963. In vivo, AAA MR strain (1.2% ± 0.6%) was highly reproducible (bias ± 95% CI, 0.03% ± 0.31%; intraclass correlation coefficient, 97.8%; coefficient of variation, 7.14%) and was lower than in the nonaneurysmal aorta (2.4% ± 1.7%). Dmax (β = 0.087) and MR strain (β= -1.563) were both associated with AAA growth rate. The MR strain remained an independent factor associated with growth rate (β= -0.904) after controlling for Dmax. Deformable image registration analysis can accurately measure the circumferential strain of the AAA wall from standard cine MRI and may offer patient-specific insight regarding AAA progression.

Peri-Operative Mortality and Survival After Repair of Abdominal Aortic Aneurysm in Advanced Age Patients: A National Study from the Norwegian Registry for Vascular Surgery Focused on Nonagenarians

Treatment of abdominal aortic aneurysm (AAA) in nonagenarians has become more frequent. This national observational cohort study aimed to investigate peri-operative mortality and survival after AAA surgery in nonagenarians in Norway. All AAA repairs registered in the Norwegian Registry for Vascular Surgery from 2015 to 2021 were identified and stratified into nonagenarians > 90 years old (n= 77), octogenarians 80 - 89 years old (n= 1 362), and patients < 80 years old (n= 4 590). The patient characteristics and comorbidities were recorded, and the 30 and 90 day mortality rates were calculated. Kaplan-Meier analysis was performed to obtain the estimated median survival and survival curves. In the nonagenarians, the 30 day mortality rates were 2.5% in asymptomatic patients, 33.3% in symptomatic patients, and 59.1% in the patients with a ruptured AAA (rAAA). The estimated median survival (years) were 3.3 (95% confidence interval [CI] 1.95 - 4.59) for asymptomatic AAA, 2.9 (interquartile range [IQR] 2.82, 5.80) for symptomatic AAA, and 0.1 for rAAA (IQR 0.01, 3.04). For nonagenarians surviving the first 90 days, the estimated median survival (years) were 4.2 (95% CI 2.56 - 5.88) for asymptomatic AAA, 3.4 (IQR 2.86, 5.80) for symptomatic AAA, and 3.8 (IQR 1.49, 4.85) for rAAA. The 90 day mortality rates were 100.0%, 80.0%, and 62.5% for asymptomatic, symptomatic, and rAAA, respectively, after open surgical repair (OSR), and 5.1%, 10.0%, and 50.0%, respectively, after endovascular aortic repair (EVAR). Peri-operative mortality and survival results after AAA surgery in nonagenarians support treatment of selected asymptomatic patients. The 90 day survivors had an expected survival of more than three years, enabling balanced decision making regarding surgical vs. conservative treatment options in this challenging cohort. EVAR is the treatment method of choice for AAA in nonagenarians because most of them would probably live longer untreated than if treated by OSR.

Pathogenesis and management of abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) causes ∼170 000 deaths annually worldwide. Most guidelines recommend asymptomatic small AAAs (30 to <50 mm in women; 30 to <55 mm in men) are monitored by imaging and large asymptomatic, symptomatic, and ruptured AAAs are considered for surgical repair. Advances in AAA repair techniques have occurred, but a remaining priority is therapies to limit AAA growth and rupture. This review outlines research on AAA pathogenesis and therapies to limit AAA growth. Genome-wide association studies have identified novel drug targets, e.g. interleukin-6 blockade. Mendelian randomization analyses suggest that treatments to reduce low-density lipoprotein cholesterol such as proprotein convertase subtilisin/kexin type 9 inhibitors and smoking reduction or cessation are also treatment targets. Thirteen placebo-controlled randomized trials have tested whether a range of antibiotics, blood pressure-lowering drugs, a mast cell stabilizer, an anti-platelet drug, or fenofibrate slow AAA growth. None of these trials have shown convincing evidence of drug efficacy and have been limited by small sample sizes, limited drug adherence, poor participant retention, and over-optimistic AAA growth reduction targets. Data from some large observational cohorts suggest that blood pressure reduction, particularly by angiotensin-converting enzyme inhibitors, could limit aneurysm rupture, but this has not been evaluated in randomized trials. Some observational studies suggest metformin may limit AAA growth, and this is currently being tested in randomized trials. In conclusion, no drug therapy has been shown to convincingly limit AAA growth in randomized controlled trials. Further large prospective studies on other targets are needed.

Evaluation of the prognostic value of computed tomography-derived body composition in patients undergoing endovascular aneurysm repair.

Endovascular aneurysm repair (EVAR) is the most common mode of repair of abdominal aortic aneurysms (AAA) in the UK. EVAR ranges from standard infrarenal repair to complex fenestrated and branched EVAR (F/B-EVAR). Sarcopenia is defined by lower muscle mass and function, which is associated with inferior perioperative outcomes. Computed tomography-derived body composition analysis offers prognostic value in patients with cancer. Several authors have evaluated the role of body composition analysis in predicting outcomes in patients undergoing EVAR; however, the evidence base is limited by heterogeneous methodology. Six hundred seventy-four consecutive patients (58 (8.6%) female, mean (SD) age 74.4 (6.8) years) undergoing EVAR and F/B-EVAR at three large tertiary centres were retrospectively recruited. Subcutaneous and visceral fat indices (SFI and VFI), psoas and skeletal muscle indices, and skeletal muscle density were measured at the L3 vertebral level from pre-operative computed tomographies. The maximally selected rank statistic technique was used to define optimal thresholds to predict mortality. There were 191 deaths during the median follow-up period of 60.0months. Mean (95% CI) survival in the low SMI versus high SMI subgroups was 62.6 (58.5-66.7) versus 82.0 (78.7-85.3) months (P<0.001). Mean (95% CI) survival in the low SFI versus high SFI subgroups was 56.4 (48.2-64.7) versus 77.1 (74.2-80.1) months (P<0.001). One-year mortality in the low SMI versus high SMI subgroups was 10% versus 3% (P<0.001). Low SMI was associated with increased odds of one-year mortality (OR 3.19, 95% CI 1.60-6.34, P<0.001). Five-year mortality in the low SMI versus high SMI subgroups was 55% versus 28% (P<0.001). Low SMI was associated with increased odds of five-year mortality (OR 1.54, 95% CI 1.11-2.14, P<0.01). On multivariate analysis of all patients, low SFI (HR 1.90, 95% CI 1.30-2.76, P<0.001) and low SMI (HR 1.88, 95% CI 1.34-2.63, P<0.001) were associated with poorer survival. On multivariate analysis of asymptomatic AAA patients, low SFI (HR 1.54, 95% CI 1.01-2.35, P<0.05) and low SMI (HR 1.71, 95% CI 1.20-2.42, P<0.01) were associated with poorer survival. Low SMI and SFI are associated with poorer long-term survival following EVAR and F/B-EVAR. The relationship between body composition and prognosis requires further evaluation, and external validation of the thresholds proposed in patients with AAA is required.

Myasthenia gravis and abdominal aortic aneurysm: a rare combination.

Abdominal aortic aneurysm in a patient with myasthenia gravis is extremely rare. We present a 64-year-old male with myasthenia gravis and an asymptomatic abdominal aortic aneurysm treated endovascularly. After extubation he suffered a cardiac arrest due to an acute myocardial infarction. Cardiopulmonary resuscitation and a primary coronary angioplasty led to a satisfactory outcome. Special care is needed due to higher rates of postoperative complications in these patients.

Proteomics Analysis of Genetic Liability of Abdominal Aortic Aneurysm Identifies Plasma Neogenin and Kit Ligand: The ARIC Study.

Genome-wide association studies have reported 23 gene loci related to abdominal aortic aneurysm (AAA)-a potentially lethal condition characterized by a weakened dilated vessel wall. This study aimed to identify proteomic signatures and pathways related to these risk loci to better characterize AAA genetic susceptibility. Plasma concentrations of 4870 proteins were determined using a DNA aptamer-based array. Linear regression analysis estimated the associations between the 23 risk alleles and plasma protein levels with adjustments for potential confounders in a race-stratified analysis of 1671 Black and 7241 White participants. Significant proteins were then evaluated for their prediction of clinical AAA (454 AAA events in 11 064 individuals), and those significantly associated with AAA were further interrogated using Mendelian randomization analysis. Risk variants proximal to PSRC1-CELSR2-SORT1, PCIF1-ZNF335-MMP9, RP11-136O12.2/TRIB1, ZNF259/APOA5, IL6R, PCSK9, LPA, and APOE were associated with 118 plasma proteins in Whites and 59 were replicated in Black participants. Novel associations with clinical AAA incidence were observed for kit ligand (HR, 0.59 [95% CI, 0.42-0.82] for top versus first quintiles) and neogenin (HR, 0.64 [95% CI, 0.46-0.88]) over a median 21.2-year follow-up; neogenin was also associated with ultrasound-detected asymptomatic AAA (N=4295; 57 asymptomatic AAA cases). Mendelian randomization inverse variance weighted estimates suggested that AAA risk is promoted by lower levels of kit ligand (OR per SD=0.67; P=1.4×10-5) and neogenin (OR per SD=0.50; P=0.03). Low levels of neogenin and kit ligand may be novel risk factors for AAA development in potentially causal pathways. These findings provide insights and potential targets to reduce AAA susceptibility.

Prognostic model for survival of patients with abdominal aortic aneurysms treated with endovascular aneurysm repair

The role of endovascular aneurysm repair (EVAR) in patients with asymptomatic abdominal aortic aneurysm (AAA) who are unfit for open surgical repair has been questioned. The impending risk of aneurysm rupture, the risk of elective repair, and the life expectancy must be balanced when considering elective AAA repair. This retrospective observational cohort study included all consecutive patients treated with standard EVAR for AAA at a referral centre between 2001 and 2020. A previously published predictive model for survival after EVAR in patients treated between 2001 and 2012 was temporally validated using patients treated at the same institution between 2013 and 2020 and updated using the overall cohort. 558 patients (91.2% males, mean age 74.9 years) were included. Older age, lower eGFR, and COPD were independent predictors for impaired survival. A risk score showed good discrimination between four risk groups (Harrel’s C = 0.70). The 5-years survival probabilities were only 40% in “high-risk” patients, 68% in “moderate-to-high-risk” patients, 83% in “low-to-moderate-risk”, and 89% in “low-risk” patients. Low-risk patients with a favourable life expectancy are likely to benefit from EVAR, while high-risk patients with a short life expectancy may not benefit from EVAR at the current diameter threshold.

Gluteal And Thigh Compartment Syndrome After Open Abdominal Aortic Aneurysm Repair

A 55-year-old male underwent elective aorto-bi-iliac bypass for asymptomatic abdominal aortic aneurysm (AAA) and left common iliac artery (LCIA) ectasia. Intraoperative assessment of the left foot revealed persistent ischemia after reperfusion, and this was thought to be related to a dissection flap or technical issue at the left limb anastomosis. To address this, a jump bypass to the left internal iliac and left common femoral artery was performed, requiring re-clamping of the left iliac system.

Infrarenal Remains Infrarenal-EVAR Suitability of Small AAA Is Rarely Compromised despite Morphological Changes during Surveillance.

The aim was to analyze small abdominal aortic aneurysm (AAA) morphology during surveillance with regard to standard endovascular aortic repair (EVAR) suitability. This retrospective single-center study included all patients (n = 52, 48 male, 70 ± 8 years) with asymptomatic AAA ≤ 5.4 cm undergoing ≥2 computed tomography angiography(CTA)/magnetic resonance imaging (MRI) studies (interval: ≥6 months) between 2010 and 2018. Aneurysm diameter, neck quality (shape, length, angulation, thrombus/calcification), aneurysm thrombus, and distal landing zone diameters were compared between first and last CTA/MRI. Resulting treatment plan changes were determined. Neck shortening occurred in 25 AAA (mean rate: 2.0 ± 4.2 mm/year). Neck thrombus, present in 31 patients initially, increased in 16. Average AAA diameters were 47.7 ± 9.3 mm and 56.3 ± 11.6 mm on first and last CTA/MRI, mean aneurysm growth rate was 4.2 mm/year. Aneurysm thrombus was present in 46 patients primarily, increasing in 32. Neck thrombus growth and neck length change, aneurysm thrombus amount and aneurysm growth and aneurysm growth and neck angulation were significantly correlated. A total of 46 (88%) patients underwent open (12/46) or endovascular (34/46) surgery. The planned procedure changed from EVAR to fenestrated EVAR in two patients and from double to triple fenestrated EVAR in one. Thus, standard EVAR suitability was predominantly maintained as the threshold diameter for surgery was reached despite morphological changes. Consecutively, a possibly different pathogenesis of infra- versus suprarenal AAA merits further investigation.

Association of Oral Anticoagulation Prescription with Clinical Events in Patients with an Asymptomatic Unrepaired Abdominal Aortic Aneurysm.

Background: Most abdominal aortic aneurysms (AAA) have large volumes of intraluminal thrombus which has been implicated in promoting the risk of major adverse events. The aim of this study was to examine the association of therapeutic anticoagulation with AAA-related events and major adverse cardiovascular events (MACE) in patients with an unrepaired AAA. Methods: Patients with an asymptomatic unrepaired AAA were recruited from four sites in Australia. The primary outcome was the combined incidence of AAA repair or AAA rupture-related mortality (AAA-related events). The main secondary outcome was MACE (the combined incidence of myocardial infarction, stroke, or cardiovascular death). The associations of anticoagulation with these outcomes were assessed using Cox proportional hazard analyses (reporting hazard ratio, HR, and 95% confidence intervals, CI) to adjust for other risk factors. Results: A total of 1161 patients were followed for a mean (standard deviation) of 4.9 (4.0) years. Of them, 536 (46.2%) patients had a least one AAA-related event and 319 (27.5%) at least one MACE. In the sample, 98 (8.4%) patients were receiving long-term therapeutic anticoagulation using warfarin (84), apixaban (7), rivaroxaban (6), or dabigatran (1). Prescription of an anticoagulant was associated with a reduced risk of an AAA-related event (adjusted HR 0.61; 95% CI 0.42, 0.90, p = 0.013), but not MACE (HR 1.16; 95% CI 0.78, 1.72, p = 0.476). Conclusions: These findings suggest that AAA-related events but not MACE may be reduced in patients prescribed an anticoagulant medication. Due to the inherent biases of observational studies, a randomized controlled trial is needed to assess whether anticoagulation reduces the risk of AAA-related events.

Progress in murine models of ruptured abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a focal dilation of the aorta that is prevalent in aged populations. The progressive and unpredictable expansion of AAA could result in aneurysmal rupture, which is associated with ~80% mortality. Due to the expanded screening efforts and progress in diagnostic tools, an ever-increasing amount of asymptomatic AAA patients are being identified yet without a cure to stop the rampant aortic expansion. A key barrier that hinders the development of effective AAA treatment is our incomplete understanding of the cellular and molecular basis of its pathogenesis and progression into rupture. Animal models provide invaluable mechanistic insights into AAA pathophysiology. However, there is no single experimental model that completely recapitulate the complex biology behind AAA, and different AAA-inducing methodologies are associated with distinct disease course and rupture rate. In this review article, we summarize the established murine models of ruptured AAA and discuss their respective strengths and utilities.

Correlation Between Proteolytic Activity and Abdominal Aortic Aneurysm Wall Morphology with Intraluminal Thrombus Volume

The aim of this study was to examine the influence of intraluminal thrombus (ILT) volume on the level of proteolytic activity and the content of abdominal aortic aneurysm (AAA) wall. The research was designed as a cross-sectional study at the Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia in the period from April 2017 to February 2018. During this period, a total of 155 patients with asymptomatic AAA underwent open surgical treatment and 50 were included in the study based on inclusion and exclusion criteria. Before surgery, patients included in the study were examined by MRI. During the operation, samples of ILT and AAA wall were taken for biochemical analysis. A statistically significant correlation was found between the volume of the ILT and largest AAA diameter (ρ=0.56; P<0.001). The correlation of the ILT volume on the anterior wall and the concentration of MMP-9, MMP-2 and NE/ELA in the wall did not find statistical significance. Also, no statistically significant association was found between the volume of ILT and the concentration of ECM proteins (collagen type 3, elastin, proteoglycan) in the corresponding part of the wall. The association of ILT volume with MDA was also of no statistical significance. There was a positive statistical significance found in correlation of volume of ILT and catalase activity in the wall of AAA (ρ=0.28, P=0.049). The volume of ILT in the aneurysmal sac seemed not to affect the level of proteolytic activity and the content of the aneurysm wall. However, a positive correlation was found between the ILT and the catalase activity. The effect of ILT on the aneurysm wall and its role in the progression of aneurysmal disease should be examined in future studies.

The Impact of the First 11 Months of the COVID-19 Pandemic on Vascular Patients’ Care and Hospitalisation Rate in the Vascular Surgery Divisions of Southern Italy

Following the Italian government decree in March 2020, three month strict lockdown measures were implemented countrywide to avoid social contact. Hospital related routines were disrupted to prioritise the management of COVID-19 cases; in particular, outpatient and elective operations were postponed. Similar prevention and public health interventions were implemented from the second half of September 2020 up to the beginning of December 2020 in response to the second wave of the pandemic. Furthermore, except for situations of proven urgency, access to General Medicine in Southern Italy was negatively impacted during the lockdowns, affecting the diagnosis, management, and surveillance of vascular patients. This study was conducted to assess the eventual impact of suspension of elective vascular surgery on the incidence rates of complications caused by common vascular conditions compared with the pre-pandemic period. A multicentre retrospective cross sectional study was carried out: 27 of 29 vascular surgery divisions, public or accredited with the National Health System, located in the Southern Italy were enrolled. Even though healthcare policies are issued at a regional level in Italy, the above mentioned regions implemented similar COVID-19 restrictions. The focus was on 13 vascular surgical activities, among which diagnosis, treatment and follow up of abdominal aortic aneurysm (AAA), internal carotid artery (ICA) stenosis, Rutherford category 3 peripheral arterial disease (R3PAD, severe claudication), chronic limb threatening ischaemia (CLTI), deep venous thrombosis (DVT), and venous ulcers were investigated, analysing the number of patients in the first 11 months of the COVID-19 pandemic, and in the prior 11 months (Table 1). Informed consent for this retrospective multicentre study was waved.Table 1Vascular surgical activities before and during the first and second wave of the COVID-19 pandemic in ItalyActivitiesApr – Dec 2019, no COVID-19(n = 9 161)Apr – Dec 2020, COVID-19(n = 7 092)pDelta – %EVAR or open repair for asymptomatic AAA891 (9.7)691 (9.7)1.0–22.4Post-EVAR surveillance1 484 (16.2)1 014 (14.3)<.001–31.7Open repair/EVAR for primary ruptured or symptomatic AAA175 (1.9)171 (2.4).030–2.3EVAR for ruptured or symptomatic AAA, or endoleak with expansion106 (1.2)80 (1.1).55–24.5Treatment for Rutherford category 3 PAD∗In socially active patients who can walk less than 50 m on a flat surface, are not responsive to supervised exercise and best medical therapy and are asking for a definitive treatment to improve their walking distance.1 401 (15.3)959 (13.5)<.001–31.5Treatment for thrombotic acute lower limb ischaemia455 (5.0)370 (5.2).57–18.7Treatment for venous ulcers588 (6.4)461 (6.5).80–21.6Diagnosis of deep vein thrombosis753 (8.2)695 (9.8)<.001–7.7Revascularisations for asymptomatic severe ICA stenosis†> 80% according to European Carotid Surgery Trial criteria, without ipsilateral cerebral ischaemia in the last six months.1 558 (17.0)934 (13.2)<.001–40.0Revascularisations for CLTI1 245 (13.6)1 204 (17.0)<.001–3.3Major amputation for CLTI358 (3.9)355 (5.0)<.001–0.8Symptomatic carotid stenosis operated between 2 and 14 days140 (1.5)153 (2.2)<.0019.3Data are presented as n (%). EVAR = endovascular aneurysm repair; AAA = abdominal aortic aneurysm; PAD = peripheral arterial disease; ICA = internal carotid artery; CLTI = chronic limb threatening ischaemia.∗ In socially active patients who can walk less than 50 m on a flat surface, are not responsive to supervised exercise and best medical therapy and are asking for a definitive treatment to improve their walking distance.† > 80% according to European Carotid Surgery Trial criteria, without ipsilateral cerebral ischaemia in the last six months. Open table in a new tab Data are presented as n (%). EVAR = endovascular aneurysm repair; AAA = abdominal aortic aneurysm; PAD = peripheral arterial disease; ICA = internal carotid artery; CLTI = chronic limb threatening ischaemia. Clinical characteristics were described with absolute and relative (percentage) frequencies. Qualitative variables were compared using the chi squared test. Percentage differences for the collected variables (delta) between pre-COVID-19 and COVID-19 periods were computed. A two tailed p value < .050 was considered statistically significant. All statistical analyses were carried out using the STATA software version 17 (StataCorp LLC, TX, USA). Table 1 summarises the main results of the study. During the pandemic period from March 2020 to January 2021, 36/1 713 (2.1%) patients who presented with CLTI, 33/501 (6.6%) patients who required major amputation, and 9/207 (4.4%) patients with stroke or transient ischaemic attacks tested positive for COVID-19. The numbers of endovascular abdominal aneurysm repair or open repair for asymptomatic AAA, treatment for venous ulcers, and severe ICA stenosis > 80% according to the European Carotid Surgery Trial on the operation waiting list complicated by total obstruction (detected at duplex scan before revascularisation, or because they became symptomatic) did not change throughout the study period. This multicentre study, covering more than one fifth of the Italian geographical area and population over a long time period, showed decreased rates of revascularisation for R3PAD and asymptomatic ICA stenosis, as well as increased rates of revascularisation (or major amputation) for CLTI and symptomatic ICA stenosis. Interestingly, in January 2021 (when the immediate pandemic restrictions were lifted) a major decrease in R3PAD and asymptomatic ICA stenosis persisted compared with pre-pandemic levels (92 [11.4%] and 87 [10.8%] vs. 175 [16.8%] and 164 [15.7%], p = .001 and .002, respectively). This analysis suggests that the delays may have further consequences in the coming months. This may be due to a shortage of staff, burnout, but also COVID infections. Project 1 (Impact of COVID-19 on scheduled vascular operations) of the international Vascular Surgery COVID-19 Collaborative (VASCC) registry aims to answer this particular question. VASCC is a combined international effort to obtain prospective data on the impact of widespread vascular surgical care delays due to an international crisis or pandemic.1Mouawad N.J. Cuff R.F. Hultgren R. Chuen J. Galeazzi E. Wohlauer M. The Vascular Surgery COVID-19 Collaborative (VASCC).J Vasc Surg. 2020; 72: 379-380Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar,2D'Oria M. Mills Sr., J.L. Cohnert T. Oderich G.S. Hultgren R. Lepidi S. et al.The "Vascular Surgery COVID-19 Collaborative" (VASCC).Eur J Vasc Endovasc Surg. 2020; 60: 489-490Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar Changes during the COVID-19 pandemic could have affected patient prognosis. Several researchers, clinicians, and policymakers have been trying to understand the real impact of the pandemic on clinical activities.3Kahlberg A. Mascia D. Bellosta R. Attisani L. Pegorer M. Socrate A.M. et al.Vascular surgery during COVID-19 emergency in hub hospitals of Lombardy: experience on 305 patients.Eur J Vasc Endovasc Surg. 2021; 61: 306-315Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar,4Pini R. Faggioli G. Vacirca A. Gallitto E. Mascoli C. Attard L. et al.Is it possible to safely maintain a regular vascular practice during the COVID-19 pandemic?.Eur J Vasc Endovasc Surg. 2020; 60: 127-134Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar Several study limitations can be highlighted. The exact numbers are not known, since patients may not have visited any medical service during these periods. Some vascular diseases were not considered: complex aortic procedures are often referred to specialist centres, and numbers would probably have been too low to be considered; arteriovenous fistulas are also performed by nephrologists; likewise, varicose vein surgery was excluded based on its postponement caused by their low priority. Only the first 11 months of the COVID-19 pandemic were evaluated against the corresponding 2019 months; as such, interannual variability cannot be excluded. The stratification of the findings based on SARS-CoV-2 positivity was not always performed: the infection could have increased the incidence of some vascular diseases (e.g., DVT). Asymptomatic severe ICA stenosis that progressed to occlusion (and thus was managed non-surgically) could have been missed, since it can cause cerebral ischaemia, which can be managed in different medical wards (e.g., stroke unit, intensive care unit, neurology, internal medicine) and thus under reported. The vascular community is called upon to raise awareness of the dangers arising from restrictions in the management of elective vascular patients during the pandemic crisis.

167 Threshold for Intervention in Females with Asymptomatic Abdominal Aortic Aneurysm (AAA)- a Literature Review

Abstract Introduction UK Small Aneurysm Trial, a study conducted in the late 90s, showed that the threshold for asymptomatic abdominal aortic repair in females would be &amp;lt; 5.5 cm. However, this threshold remained debatable. Our aim is to search for the most recent evidence in regard to the AAA repair threshold in females, and factors affecting the decision to intervene. Method PRISMA Flow from 2011–2021 was utilized using keywords on PubMed resulted in 913 articles. Upon further review by and full paper, 2 Cohort studies (n = 10102) and 11 narrative and retrospective reviews were found. Results 2 cohort studies (n = 10102), as well as 2 other studies, showed that the threshold should be 5 cm. There was a split in opinions between another retrospective (n = 4) reviews which argued for a cut-off between &amp;lt; 5 cm and 5.2 cm. The others, showed evidence of better outcomes repairing asymptomatic AAA at a threshold &amp;lt; 5 cm. Meanwhile, 3 studies recommended using ASI diameter &amp;lt; 5.5 cm^2. Overall, the Intervention threshold being 5 cm or less is reasonable for females since they have a 4-fold men risk of rupture rates at 5.5 cm in addition to significant physiologically smaller aortic diameter (1.75 cm) compared with males (2.4 cm). Conclusions The threshold for operating on female asymptomatic AAA should be lower than males, with some evidence suggesting &amp;lt; 5 cm compared to 5.5 in men. Patient tailored and risk assessment approach is recommended. Hence, this will be our standard for upcoming clinical audit.

Endovascular Repair of Narrow Distal Aortas Using an In Situ Fenestration Technique

PurposeTo demonstrate that in situ fenestration (ISF) of an aorto-uni-iliac endograft to treat aortoiliac disease with narrow distal aorta (NDA) vessels is effective and safe. Materials and MethodsData for all patients treated by use of ISF between August 2014 and December 2019 were retrospectively analyzed. The series included 27 patients, aged 70 years ± standard error (SE) 11. The pathologies treated included aortoiliac occlusive disease (n = 16), asymptomatic abdominal aortic aneurysm (n = 8), and a ruptured abdominal aortic aneurysm (n = 3). The technique consisted of deploying an aorto-uni-iliac graft, which was converted into a bifurcated repair through contralateral iliac ISF. The inclusion criteria encompassed the presence of an abdominal aortic aneurysm (diameter of >50 mm, rapid growth, ruptured or symptomatic) associated with NDA or the presence of severe aortoiliac occlusive disease with NDA. NDA is defined as an aortic diameter of <16 mm. ResultsThe mean aortic bifurcation diameter was 11.9 mm ± SE 1.5. In total, 55% of the fenestrated endografts were performed with a multifilament polyester endograft and 45% with expanded polytetrafluoroethylene endograft. Technical success was 100%. Fluoroscopy time was 28 minutes ± SE 12, and 94 mL ± SE 43 of iodinated contrast medium was used. In the postoperative course, a single minor retroperitoneal hematoma was identified. The mean hospital stay was 5 days ± SE 3. At the mean follow-up of 26 months ± SE 22, overall primary patency was 94% and no endoleak was observed at the ISF site. ConclusionsThe ISF technique is safe and effective in the treatment of aortoiliac disease with NDA. Comparisons with alternative techniques are needed to determine the long-term durability.

C-reactive protein to albumin ratio provides important long-term prognostic information in patients undergoing endovascular abdominal aortic repair.

The prognostic value of C-reactive protein/albumin ratio (CAR) is of import in cardiovascular diseases. Our aim was to evaluate the impact of the CAR in patients with asymptomatic abdominal aortic aneurysm (AAA) undergoing endovascular aneurysm repair (EVAR). We retrospectively evaluated 127 consecutive patients who underwent technically successful elective EVAR procedure between December 2014 and September 2020. The optimal CAR cut-off value was determined by using receiver operating characteristic (ROC) curve analysis. Based on the cut-off value, we investigated the association of CAR with long-term all-cause mortality. 32 (25.1%) of the patients experienced all-cause mortality during a mean 32.7 ± 21.7 months' follow-up. In the group with mortality, CAR was significantly higher than in the survivor group (4.63 (2.60-11.88) versus 1.63 (0.72-3.24), p < 0.001). Kaplan-Meier curves showed a higher incidence of all-cause mortality in patients with high CAR compared to patients with low CAR (log-rank test, p < 0.001). Multivariable Cox regression analysis revealed that glucose ≥ 110mg/dL (HR: 2.740; 95% CI: 1.354-5.542; p = 0.005), creatinine ≥ 0.99mg/dL (HR: 2.957, 95% CI: 1.282-6.819, p = 0.011) and CAR > 2.05 (HR: 8.190, 95% CI: 1.899-35.320, p = 0.005) were the independent predictors of mortality. CAR was associated with a significant increase in postoperative long-term mortality in patients who underwent EVAR. Preoperatively calculated CAR can be used as an important prognostic factor.

Protocol for the Metformin Aneurysm Trial (MAT): a placebo-controlled randomised trial testing whether metformin reduces the risk of serious complications of abdominal aortic aneurysm

BackgroundMultiple observational studies have associated metformin prescription with reduced progression of abdominal aortic aneurysm (AAA). The Metformin Aneurysm Trial (MAT) will test whether metformin reduces the risk of AAA rupture-related mortality or requirement for AAA surgery (AAA events) in people with asymptomatic aneurysms.MethodsMAT is an international, multi-centre, prospective, parallel-group, randomised, placebo-controlled trial. Participants must have an asymptomatic AAA measuring at least 35 mm in maximum diameter, no diabetes, no contraindication to metformin and no current plans for surgical repair. The double-blind period is preceded by a 6-week, single-blind, active run-in phase in which all potential participants receive metformin. Only patients tolerating metformin by taking at least 80% of allocated medication will enter the trial and be randomised to 1500 mg of metformin XR or an identical placebo. The primary outcome is the proportion of AAA events defined as rupture-related mortality or need for surgical repair. Secondary outcomes include AAA growth, major adverse cardiovascular events and health-related quality of life. In order to test if metformin reduced the risk of AAA events by at least 25%, 616 primary outcome events will be required (power 90%, alpha 0.05).DiscussionCurrently, there is no drug therapy for AAA. Past trials have found no convincing evidence of the benefit of multiple blood pressure lowering, antibiotics, a mast cell inhibitor, an anti-platelet drug and a lipid-lowering medication on AAA growth. MAT is one of a number of trials now ongoing testing metformin for AAA. MAT, unlike these other trials, is designed to test the effect of metformin on AAA events. The international collaboration needed for MAT will be challenging to achieve given the current COVID-19 pandemic. If this challenge can be overcome, MAT will represent a trial unique within the AAA field in its large size and design.Trial registrationAustralian Clinical Trials ACTRN12618001707257. Registered on 16 October 2018

Clinical Significance of Increased Computed Tomography Attenuation of Periaortic Adipose Tissue in Patients With Abdominal Aortic Aneurysms.

Recent imaging studies reported an association between vascular inflammation and progression of abdominal aortic aneurysm (AAA). This study investigated the clinical significance of periaortic adipose tissue inflammation derived from multidetector computed tomography angiography (MDCTA).Methods and Results:Patients with asymptomatic AAA (n=77) who underwent an index and >6 months follow-up MDCTA examinations were retrospectively investigated. MDCTA analysis included AAA diameter and the periaortic adipose tissue attenuation index (PAAI). The PAAI was defined as the mean CT attenuation value within a predefined range from -190 to -30 Hounsfield units of adipose tissue surrounding the AAA. The growth rate of the AAA was calculated as the change in diameter. AAA progression (AP) was defined as an AAA growth rate ≥5 mm/year. Univariate and multivariate logistic regression analysis were performed to determine the predictors of AP. AP was observed in 19 patients (24.7%), the median baseline AAA diameter was 38.9 mm (interquartile range [IQR] 32.7-42.9 mm), and the median growth rate was 3.1 mm/year (IQR 1.5-4.9 mm/year). Baseline AAA diameter (odds ratio [OR] 1.16; 95% confidence interval [CI] 1.05-1.28; P=0.001) and PAAI (OR 1.12; 95% CI 1.05-1.20; P=0.004) were independent predictors of AP. PAAI was an independent and significant predictor of AP, supporting the notion that local adipose tissue inflammation may contribute to aortic remodeling.

Association of abdominal aortic aneurysm diameter indexed to patient height with symptomatic presentation and mortality

BackgroundThe current guidelines have recommended repair of abdominal aortic aneurysms (AAAs) according to the maximal AAA diameter and/or its growth rate. However, many studies have suggested that the AAA diameter alone is not sufficient to predict the risk of rupture or symptomatic presentation. Several investigators have attempted to relate the AAA diameter to the body surface area in predicting for rupture. However, these calculations have not resulted in conclusive evidence. We sought in the present analysis to introduce a novel diameter-to-height index (DHI) and test its utility in predicting for symptomatic presentations, including rupture and 30-day and 5-year mortality. MethodsThe Vascular Quality Initiative database (2003-2020) was used to identify patients who had undergone open or endovascular AAA repair. The DHI was defined as the AAA diameter in centimeters divided by the height in centimeters, yielding a score of 1 to 10. Multivariable logistic regression analysis was performed to assess the risk of symptomatic presentation, including rupture and 30-day mortality. Receiver operating characteristic curves were plotted, and survival analysis techniques were used to determine the hazard of 5-year mortality. ResultsA total of 64,595 patients were identified, of whom, 16.3% had presented with symptomatic AAAs, including rupture. Endovascular AAA repair was performed for 69.8% of the symptomatic AAAs and 84.3% of asymptomatic AAAs (P < .001). The symptomatic group were more likely to be women (24.6% vs 19.8%; P < .001) and Black (7.81% vs 4.44%; P < .001). The mean DHI was higher in the symptomatic group than in the asymptomatic group (mean DHI, 3.92 ± 1.1 vs 3.24 ± 0.7; P < .001). The adjusted odds of a symptomatic presentation increased with an increasing DHI (adjusted odds ratio [aOR], 1.70; 95% confidence interval [CI], 1.59-1.83; P < .001). Active smoking increased the risk of a symptomatic presentation (aOR, 1.38; 95% CI, 1.28-1.51; P < .001). However, the use of preoperative statins and beta-blockers significantly reduced the odds of a symptomatic presentation (aOR, 0.58; 95% CI, 0.53-0.64; P < .001; and aOR, 0.76; 95% CI, 0.69-0.84; P < .001), respectively. Compared with the AAA diameter, the receiver operating characteristic curve for the DHI to predict for symptomatic status was slightly, but significantly, higher (aOR, 0.702; 95% CI, 0.695-0.708; vs aOR, 0.695; 95% CI, 0.688-0.701; P < .001). The DHI increment was associated with a 1.08 greater odds of 30-day mortality (aOR, 1.08; 95% CI, 1.01-1.15; P < .001) for those with symptomatic AAAs. Similarly, the hazard of 5-year mortality was increased with an increasing DHI (adjusted hazard ratio, 1.20; 95% CI, 1.13-1.29; P < .001) only for those with asymptomatic AAAs. ConclusionsThe DHI is a simple tool that could be more effective than the AAA diameter in predicting for symptomatic presentations. The DHI varied by sex and race, which could collectively help to provide an individualized prognosis. The DHI can additionally predict the 5-year mortality after AAA repair for those with asymptomatic AAAs only. However, the odds of 30-day mortality remained similar in both groups.