Abdominal Aortic Aneurysm Rupture Research Articles

Endoleak Type III and COVID-19: A Lethal Combination

A 72 year old man presented with new onset intermittent claudication and weak femoral pulses bilaterally. After endovascular repair of a 6.0 cm abdominal aortic aneurysm (AAA) in 2018 (AFX2 plus Vela, Endologix, Irvine, CA, USA), the patient discontinued follow up after three months with a stable aneurysm. Computed tomography angiography showed AAA diameter increase to 6.8 cm and component disconnection (type III endoleak, arrow, A). Decreased main body perfusion caused claudication (arrow, B). Open repair risk was considered too high because of an active COVID-19 infection. While waiting for endovascular materials, the patient died in hospital from AAA rupture, confirmed by autopsy.Image 1

Resultados de los tipos de endoprótesis en la reparación endovascular del aneurisma aórtico abdominal: experiencia a largo plazo de un centro colombiano de alta complejidad, el primer ejemplo latinoamericano

Introduction: Endovascular abdominal aortic aneurysm repair (EVAR) devices are associated with a higher rate of complications at 5-year follow-up. At least 30% of patients with EVAR devices require some type of reintervention (whether endovascular or open) at 10-year follow-up. These complications include endoleak, abdominal aortic aneurysms rupture, graft migration, occlusion or infection. The objective of this paper was to determine the rates of failure for each type of EVAR stent-graft used in our local population. Also, this paper is the first step to create a Colombian and Latin American transnational EVAR device registry. Material and method: Single-center retrospective observational cohort study. Thirty-four patients with abdominal aortic aneurysms (AAA) treated with EVAR were included from 2011 through 2017. Data were collected from the patients’ electronic medical records.Results: The stent-graft Endologicx Ba (Endologix, Irvine, CA, United States), Excluder (W.L. Gore, Newark, DE, United States), Zenith (Cook Medical, Bloomington, IN, United States), and Nellix endovascular aneurysm sealing system (EVAS) (Endologix, Santa Rosa, CA, United States) were not associated with any endoleaks or any type of complications after the EVAR procedure. The Aorfix (Lombard, Didcot, United Kingdom), and Endurant (Medtronic, Minneapolis, MN, United States) stent-grafts had rates of type II endoleak (in 1 and 2 patients) of 2.9% and 5.8%, respectively that closed spontaneously. No stent-graft developed type I, III or IV endoleaks or any endovascular or open reinterventions were needed. Conclusions: This study shows that the different types of stent-graft used for to treat AAA with EVAR can be used in a safe and feasible way with good postoperative clinical outcomes in the Latin American population.

Abstract 298: Ketosis Prevents Abdominal Aortic Aneurysm Progression And Rupture In Male Rats

Abdominal aortic aneurysms (AAA) are common in aging populations, and its rupture is associated with high mortality. There is no effective medical therapy for the prevention of AAA expansion and rupture. Ketone bodies (KB) are argued to produce novel responses against injury. Serum KB are elevated through a ketogenic diet (KD) or the intake of exogenous KB (EKB). We hypothesize that ketosis can reduce AAA expansion and risk of rupture. Male Sprague-Dawley rats underwent intraluminal exposure to porcine pancreatic elastase (PPE) to induce AAA formation. Rats were also administered daily β-aminopropionitrile (BAPN) to promote AAA rupture. Control rats (N=12) were fed a standard diet (SD). Treated rats were given either a KD (N=9) or EKB (N=10) starting 3 days post AAA induction. Ketosis was verified by blood BHB level >0.5mmol/L. In vivo aortic diameter was evaluated by USG. After 2 weeks, survival animals were harvested, and AAA tissue analysis was performed. Rupture AAA was determined by necropsy. Rats treated with KD consistently remained in ketosis, while rats treated with EKB remained in ketosis for only 8-hour per day. AAA size was significantly reduced (p<0.01 and p<0.05) in both, KD and EKB groups at week 1 and 2 respectively. Rupture rate was also reduced in the KD and EKB groups (22% and 40%, respectively) compared to 67% in the SD group (p=0.03 and 0.12, respectively). AAA trichrome staining demonstrated greater content of collagen in KD and EKB groups when compared to SD group (p=0.08 and 0.02, respectively). AAA gelatin zymography demonstrated significantly decreased active MMP 9 levels in KD and EKB groups (p<0.05) while total MMP 2 was attenuated in the KD group (p<0.01). Ketosis appears to reduce AAA expansion and risk of rupture. This may have resulted from AAA increased collagen deposition as well as decreased MMP activity. These findings provide initial impetus to investigate whether ketosis in patients with small AAAs can prevent expansion and risk of rupture.

Abstract 363: Irf8 And Securinine: Seeking Treatments For Abdominal Aortic Aneurysm

Objective: Abdominal aortic aneurysm (AAA) is defined as local weakening and dilatation of the abdominal aorta ≥50% and has high incidence in elderly. Current therapy is limited to surgical repair, only, no pharmacological therapy has shown effectiveness against AAA development and growth. Untreated AAA rupture is highly associated with death, and aged patients are at augmented risk for surgical complications. We therefore sought to identify novel agents that could be employed for medical AAA therapy. Methods: Using whole genome DNA methylation analysis (RRBS-Seq) in a transgenerational model of murine AAA, combined with transcriptional analysis of murine AAA tissue, we identified interferon regulatory factors (IRFs: a group of immune-system-related transcription factors (TF)), as major drivers of AAA risk and pathophysiology. We performed TF enrichment analysis that specifically suggested IRF8 as being crucial for AAA development. Drug Signatures Database (DSigDB) and Connectivity Map (CMap) analysis identified securinine, an alkaloid and traditional Chinese herbal medicine derived from Securinega suffruticosa , as a probable IRF8 inhibitor. Its vascular effects are relatively unknown. Results: We studied the effects of securinine using the porcine pancreatic elastase (PPE) model of AAA. Sonographic imaging data of 28-day securinine-treated mice (15 mg/kg) showed smaller aneurysm diameters and significantly downregulated gene expression of IRF8 and IFN-γ compared to control PPE groups. Conclusion: These data suggest that securinine may have therapeutic benefits on AAA development, potentially through regulation of IRF8.

Complex and Successful Management of a Symptomatic Isolated Abdominal Aortic Aneurysm in a Pregnant Woman with Marfan Syndrome.

Aortopathies associated to Marfan syndrome (MFS) are important causes of maternal death during pregnancy. We present a 27-year-old and 24-week pregnant MFS woman who arrived to the emergency department with increasing abdominal pain; an obstetric ultrasound showed an Abdominal Aortic Aneurysm (AAA), a multislice computed tomography angiography (CTA) confirmed and demonstrated a 7.3centimeter (cm) infrarenal AAA without evidence of dissection. A multidisciplinary committee determined that an open repair would lead to a significantly high maternal-fetal morbidity and mortality. Although endovascular repair (EVAR) in MFS patients remains controversial, an urgent bridge therapy was considered to be the best option. She was transferred to the angiography suite for EVAR to prevent AAA rupture and ensure a satisfactory pregnancy. The patient and fetus presented no complications during the procedure and were discharged 3days later. She continued her pregnancy without eventualities and an elective C-section was performed on week 36. A CTA imaging at 12months revealed type 1A and 3 endoleaks, we decided to perform endograft explant and a definitive open repair, there were no complications during the procedure, the patient is currently asymptomatic. Our case illustrates a complex decision and management that successfully avoid morbidity and mortality of a MFS mother and her product; additionally, this experience reinforces the need for lifelong and close surveillance in these patients.

Identification of Risk Factors and Development of Predictive Risk Score Model for Mortality after Open Ruptured Abdominal Aortic Aneurysm Repair.

Background and Objectives: Despite the relatively large number of publications concerning the validation of these models, there is currently no solid evidence that they can be used with absolute precision to predict survival. The goal of this study is to identify preoperative factors that influenced 30-day mortality and to create a predictive model after open ruptured abdominal aortic aneurysm (RAAA) repair. Materials and Methods: This was a retrospective single-center cohort study derived from a prospective collected database, between 1 January 2009 and 2016. Multivariate logistic regression analysis was used to identify all significant predictive factors. Variables that were identified in the multivariate analysis were dichotomized at standard levels, and logistic regression was used for the analysis. To ensure that dichotomized variables were not overly simplistic, the C statistic was evaluated for both dichotomized and continuous models. Results: There were 500 patients with complete medical data included in the analysis during the study period. Of them, 37.6% were older than 74 years, and 83.8% were males. Multivariable logistic regression showed five variables that were predictive of mortality: age > 74 years (OR = 4.01, 95%CI 2.43–6.26), loss of consciousness (OR = 2.21, 95%CI 1.11–4.40), previous myocardial infarction (OR = 2.35, 95%CI 1.19–4.63), development of ventricular arrhythmia (OR = 4.54, 95%CI 1.75–11.78), and DAP < 60 mmHg (OR = 2.32, 95%CI 1.17–4.62). Assigning 1 point for each variable, patients were stratified according to the preoperative RAAA mortality risk score (range 0–5). Patients with 1 point suffered 15.3% mortality and 3 points 68.2% mortality, while all patients with 5 points died. Conclusions: This preoperative RAAA score identified risk factors readily assessed at the bedside and provides an accurate prediction of 30-day mortality after open repair of RAAA.

Single centre experience with Excluder® stent graft; 17-year outcome.

BackgroundEndovascular abdominal aortic aneurysm repair (EVAR) has become a mainstay of abdominal aorta aneurysm treatment. Long term follow-up on specific stent grafts is needed.Patients and methodsThis study included 123 patients (104 men; mean age 73.0 years, range 51–89) with abdominal aorta aneurysm, treated with Excluder® stent graft between October 2002 and June 2008. Periprocedural and follow-up data were retrieved by reviewing the records of our institution, while time and cause of death were retrieved from the National Institute of Public Health. If an abdominal aortic aneurysm rupture was listed as the cause of death, records were retrieved from the institution that issued the death certificate. Our primary goal was to assess the primary technical success rate, type 1 and type 2 endoleak, reintervention free survival, 30-day mortality, the overall survival and aneurysm rupture-free survival.ResultsThe median follow-up was 9.7 years (interquartile range, 4.6–13.8). The primary technical success was 98.4% and the 30-day mortality accounted for 0.8%. Secondary procedures were performed in 29 (23.6%) patients during the follow-up period. The one-, five-, ten-, fifteen- and seventeen-year overall survival accounted for 94.3%, 74.0%, 47.2%, 35.8% and 35.8%, while the aneurysm-related survival was 98.4%, 96.3%, 92.6%, 92.6%, 92.6%. In seven (5.7%) patients, abdominal aortic rupture was found as the primary cause of death during follow-up.ConclusionsOur data showed that EVAR with Excluder® stent graft offers good long-term results. More than 75% of patients can be treated completely percutaneously. Late ruptures do occur in the first ten years, raising awareness about regular medical controls.

Combined Curvature and Wall Shear Stress Analysis of Abdominal Aortic Aneurysm: An Analysis of Rupture Risk Factors

PurposeTo discuss the risk factors for abdominal aortic aneurysm rupture based on geometric and hemodynamic parameters.MethodsWe retrospectively reviewed the clinical data of those who were diagnosed with an abdominal aortic aneurysm by computed tomography angiography at our hospital between October 2019 and December 2020. Thirty-five patients were included in the ruptured group (13 patients) and the unruptured group (22 patients). We analyzed the differences and correlations of anatomical factors and hemodynamic parameters between the two groups using computational fluid dynamics based on computed tomography angiography.ResultsThere were significant differences in the maximum diameter [(79.847 ± 10.067) mm vs. (52.320 ± 14.682) mm, P < 0.001], curvature [(0.139 ± 0.050) vs. 0.080 (0.123 − 0.068), P = 0.021], and wall shear stress at the site of maximal blood flow impact [0.549(0.839 − 0.492) Pa vs. (1.378 ± 0.255) Pa, P < 0.001] between the ruptured and unruptured groups, respectively. And in the ruptured group, wall shear stress at the rupture site was significantly different from that at the site of maximal blood flow impact [0.025 (0.049 − 0.018) Pa vs. 0.549 (0.839 − 0.492) Pa, P = 0.001]. Then, the maximum diameter and curvature were associated with rupture (maximum diameter: OR: 1.095, P = 0.003; curvature: OR: 1.142E + 10, P = 0.012). Most importantly, curvature is negatively correlated with wall shear stress (r = − 0.366, P = 0.033).ConclusionsBoth curvature and wall shear stress can evaluate the rupture risk of aneurysm. Also, curvature can be used as the geometric substitution of wall shear stress.

Risk factors, risk stratification and risk-specific surveillance strategies after endovascular aneurysm repair: study protocol for a Delphi study by the International RIsk Stratification in EVAR (IRIS-EVAR) working group

IntroductionSeveral risk factors for adverse events after endovascular aneurysm repair (EVAR) have been described, but there is no consensus on their comparative prognostic significance, use in risk stratification and application...

The Effects of Geometric Features of Intraluminal Thrombus on the Vessel Wall Oxygen Deprivation.

The objective of this paper is to analyze the association of intraluminal thrombus (ILT) presence and morphology with oxygen transport in abdominal aortic aneurysms (AAA) and local hypoxia. The biomechanical role of the ILT layer in the evolution of the aneurysm is still not fully understood. ILT has been shown to create an inflammatory environment by reducing oxygen flux to the arterial wall and therefore decreasing its strength. It has been also hypothesized that the geometry of the ILT may further affect AAA rupture. However, no previous research has attempted to explore the effect of morphological features of ILT on oxygen distributions within the AAA, in a systematic manner. In this study, we perform a comprehensive analysis to investigate how physiologically meaningful variations in ILT geometric characteristics affect oxygen transport within an AAA. We simulate twenty-seven AAA models with variable ILT dimensions and investigate the extent to which ILT attenuates oxygen concentration in the arterial wall. Geometric variations studied include ILT thickness and ILT length, as well as the bulge diameter of the aneurysm which is related to ILT curvature. Computer simulations of coupled fluid flow-mass transport between arterial wall, ILT, and blood are solved and spatial variations of oxygen concentrations within the ILT and wall are obtained. The comparison of the results for all twenty-seven simulations supports the hypothesis that the presence of ILT in AAA correlates to significantly impaired oxygen transport to the aneurysmal wall. Mainly, we observed that ILT thickness and length are the parameters that influence decreased oxygen flow and concentration values the most, and thick thrombi exacerbate hypoxic conditions in the arterial wall, which may contribute to increased tissue degradation. Conversely, we observed that the arterial wall oxygen concentration is nearly independent of the AAA bulge diameter. This confirms that consideration of ILT size and anatomy is crucial in the analysis of AAA development.

Nationwide Outcomes of Octogenarians Following Open or Endovascular Management After Ruptured Abdominal Aortic Aneurysms

Purpose: Octogenarians are known to have less-favorable outcomes following ruptured abdominal aortic aneurysm (rAAA) repair compared with their younger counterparts. Accurate information regarding perioperative outcomes following rAAA-repair is important to evaluate current treatment practice. The aim of this study was to evaluate perioperative outcomes of octogenarians and to identify factors associated with mortality and major complications after open surgical repair (OSR) or endovascular aneurysm repair (EVAR) of a rAAA using nationwide, real-world, contemporary data. Methods: All patients that underwent EVAR or OSR of an infrarenal or juxtarenal rAAA between January 1, 2013, and December 31, 2018, were prospectively registered in the Dutch Surgical Aneurysm Audit (DSAA) and included in this study. The primary outcome was the comparison of perioperative outcomes of octogenarians versus non-octogenarians, including adjustment for confounders. Secondary outcomes were the identification of factors associated with mortality and major complications in octogenarians. Results: The study included 2879 patients, of which 1146 were treated by EVAR (382 octogenarians, 33%) and 1733 were treated by OSR (410 octogenarians, 24%). Perioperative mortality of octogenarians following EVAR was 37.2% versus 14.8% in non-octogenarians (adjusted OR=2.9, 95% CI=2.8–3.0) and 50.0% versus 29.4% following OSR (adjusted OR=2.2, 95% CI=2.2–2.3). Major complication rates of octogenarians were 55.4% versus 31.8% in non-octogenarians following EVAR (OR=2.7, 95% CI=2.1–3.4), and 68% versus 49% following OSR (OR=2.2, 95% CI=1.8–2.8). Following EVAR, 30.6% of the octogenarians had an uncomplicated perioperative course (UPC) versus 49.5% in non-octogenarians (OR=0.5, 95% CI=0.4–0.6), while following OSR, UPC rates were 20.7% in octogenarians versus 32.6% in non-octogenarians (OR=0.5, 95% CI=0.4–0.7). Cardiac or pulmonary comorbidity and loss of consciousness were associated with mortality and major complications in octogenarians. Interestingly, female octogenarians had lower mortality rates following EVAR than male octogenarians (adjusted OR=0.7, 95% CI=0.6–0.8). Conclusion: Based on this nationwide study with real-world registry data, mortality rates of octogenarians following ruptured AAA-repair were high, especially after OSR. However, a substantial proportion of these octogenarians following OSR and EVAR had an uneventful recovery. Known preoperative factors do influence perioperative outcomes and reflect current treatment practice.

Long-term outcomes of endovascular aneurysm repair according to instructions for use adherence status

ObjectiveEndovascular aneurysm repair (EVAR) has become the standard treatment for abdominal aortic aneurysms (AAAs). Endovascular device manufacturers have defined specific anatomic criteria for the aneurysm characteristics that should be observed as instructions for use (IFU) for specific grafts. In clinical practice, the prevalence of performing EVAR outside the IFU has been high. In the present study, we aimed to determine the effects of nonadherence to the IFU on the outcomes. MethodsPatients who had undergone EVAR for an infrarenal AAA between 2005 and 2013 were included. IFU nonadherence was defined as any violation of device-specific IFU criteria and was compared with IFU adherence. The primary outcomes were all-cause mortality, aneurysm-related mortality, AAA rupture, graft-related adverse events (GRAEs), including limb-related adverse events, and type Ia endoleaks. A second aim was to study whether the prevalence of EVAR performed outside the IFU has increased over time. ResultsA total of 258 patients were included, 144 (55.8%) of whom had been treated according to the IFU and 114 (44.2%) outside the IFU. In the IFU nonadherence group, all-cause mortality (hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.02-1.89; P = .037) and aneurysm-related mortality (HR, 5.1; 95% CI, 1.4-18.6; P = .015), and the incidence of AAA rupture (HR, 5.4; 95% CI, 1.1-26.6; P = .036) and GRAEs (HR, 1.7; 95% CI, 1.1-2.8; P = .025). No significant association was found between the incidence of type Ia endoleaks and neck-related IFU or limb-related adverse events and iliac-related IFU. However, neck length was a risk factor for type Ia endoleaks (HR, 18.2, 95% CI, 6.3-52.2; P < .001), aneurysm-related mortality (HR, 8.7; 95% CI, 1.8-41.6; P = .007), AAA rupture (HR, 21.7; 95% CI, 2.8-166; P = .003), and GRAEs (HR, 4.4; 95% CI, 2.0-9.7; P < .001). An IFU violation regarding neck angulation was also a risk factor for all-cause mortality (HR, 2.0; 95% CI, 1.1-3.7; P = .032), aneurysm-related mortality (HR, 7.6; 95% CI, 1.4-42.8; P = .021), AAA rupture (HR, 79.4; 95% CI, 6.3-999; P = .001), and GRAEs (HR, 4.3; 95% CI, 1.9-9.5; P < .001). The prevalence of EVAR performed outside the IFU did not increase over time. ConclusionsPerforming EVAR outside the IFU had a negative effect on outcomes, including all-cause mortality, aneurysm-related mortality, AAA rupture, and GRAEs. Neck angulation and neck length seemed to be the most crucial aneurysm characteristics.

Association between neighborhood deprivation and presenting with a ruptured abdominal aortic aneurysm before screening age

ObjectiveRecent data indicate social determinants of health (SDOH) have a great impact on prevention and treatment outcomes across a broad variety of disease states, especially cardiovascular diseases. The area deprivation index (ADI) is a validated measure of neighborhood level disadvantage capturing key social determinate factors. Abdominal aortic aneurysm rupture (rAAA) is highly morbid, but also preventable through evidence-based screening. However, the association between rAAA and SDOH is poorly characterized. Our objective is to study the association of SDOH with rAAA and screening age. MethodsThis retrospective study included patients who underwent operative repair of a rAAA at a multihospital healthcare system (2003-2019). Deprivation was measured by the ADI (scale 1-100), grouped into quintiles for simplicity, with higher quintiles indicating greater deprivation. Patients with the highest quintile ADI (89-100) were categorized as the most deprived. We investigated the association between neighborhood deprivation with the odds of (i) undergoing repair for rAAA before screening age 65 and (ii) undergoing endovascular aortic repair (EVAR) using logistic regression, sequentially modeling nonmodifiable then both nonmodifiable and modifiable confounding variables. ResultsThere were 632 patients who met the inclusion criteria (aged 74.2 ± 9.4 years; 174 women [27.6%]; 564 White [89.2%]; ADI 66.8 ± 22.3). Those from the most deprived neighborhoods (n = 118) were younger (71.7 ± 10.0 years vs 74.8 ± 9.2 years; P = .002), more likely to be female (36% vs 26%; P = .031), more likely to be Black (5.9% vs 0.4%; P = .007), and fewer underwent EVAR (28% vs 39.5%; P = .020) compared with those from other neighborhoods. On sequential modeling, residing in the most deprived neighborhoods was associated with undergoing rAAA repair before age 65 after adjusting for nonmodifiable factors (odds ratio [OR], 2.02; 95% confidence interval [CI], 1.39-2.95; P < .001), and nonmodifiable as well as modifiable factors (OR, 2.22; 95% CI, 1.56-3.16; P < .001). Those in the most deprived neighborhoods had a lower odds of undergoing EVAR compared with open repair after adjusting for nonmodifiable factors (OR, 0.64; 95% CI, 0.41-0.98; P = .042), and nonmodifiable as well as modifiable factors (OR, 0.61; 95% CI, 0.37-0.99; P = .047). ConclusionsAmong patients who underwent rAAA, residing in the most deprived neighborhoods was associated with greater adjusted odds of presenting under age 65 and undergoing an open repair. These neighborhoods represent tangible geographic targets that may benefit from a younger screening age, enhanced education, and access to care. These findings stress the importance of developing strategies for early prevention and diagnosis of cardiovascular diseases among patients with disadvantageous SDOH.

Characteristic distribution of eicosapentaenoic acid in human abdominal aortic aneurysm wall

Abdominal aortic aneurysm (AAA) is a vascular disease in which the abdominal aorta gradually dilates. Dilation of AAA is associated with the aortic wall weakness induced by chronic inflammation (1). Several epidemiologic studies reported that consumption of fish is associated with the prevention of AAA. Animal and human studies suggested n-3 PUFAs can protect against AAA development and rupture. These previous data provide evidence to suggest the suppressive effect of n-3 PUFAs on AAA, which has no pharmaceuticals; however, the distribution of n-3 PUFAs in the aorta is a “missing link” to understand mechanisms underlying suppressive effects of them.

In-hospital outcomes of ruptured abdominal aortic aneurysms: A single center experience.

Introduction: Ruptured abdominal aortic aneurysm (RAAA) is a catastrophic condition with in-hospital mortalities up to 89%. Patient survival depends on multiple factors; however, prompt surgery is essential to prevent mortality. We report the in-hospital outcomes of RAAA at a high-volume and teaching vascular surgery center in Iran. Methods: This study is a single-center retrospective analysis of patients with infrarenal RAAA during February 20, 2012 to December 21, 2019 at Shohada-Tajrish Medical Center, Tehran,Iran. We identified 66 patients with RAAA during the study period. The patients were dividedinto two groups based on their transfer status (Transfer group versus non-transfer group). The primary outcome was in-hospital death. The secondary outcomes were in-hospital myocardial infarction (MI), abdominal compartment syndrome (ACS) and postoperative renal dysfunction requiring dialysis. Results: The mean age of the patients was 74.2 ± 8.3 years. Forty-seven patients (71.2%) were transferred to our center from other institutions. There were 46 in-hospital deaths (69.7%) and three in-hospital MIs (4.5%). Three patients (4.5%) had postoperative ACS and six patients (9.1%)had postoperative renal dysfunction requiring dialysis. Transfer patients had an increased rate of in-hospital death compared to non-transferred patients (76.6.1% versus 52.6%); however, the difference was not statistically significant (P =0.055). Conclusion: We found no significant different between operative mortality of transferred and non-transferred RAAA patients. Transfer of patients to tertiary centers with experienced vascular surgeons may delay the surgery. However, the transfer may be inevitable in areas where the optimal care of RAAA patients is not possible.

26 Running a Safe Aortic Service in the Covid-Era

Abstract Introduction Within the Covid-19 pandemic, elective surgery has been cancelled to increase critical care capacity. With two thirds of abdominal aortic aneurysm ruptures lethal, it is important to consider how to run a safe aortic service within the pandemic. Vascular patients have an increased risk of mortality from Covid-19. By considering ambulatory care, shortening hospital stay and discharging to level 1 care for non-complex infrarenal endovascular aneurism repairs (EVAR), critical care capacity can be kept available and exposure to nosocomial Covid-19 can be reduced. Method A retrospective audit of EVAR patient’s documentation examined the ASA, level of postoperative care, time to discharge, geographical and personal care factors. These were compared with pre-established criteria deeming suitability for ambulatory or ward level care. Results were presented locally and subsequent reaudit conducted. Results The initial audit included 40 records. 30% of patients were potential targets for ambulatory care with the median discharge on postoperative day 3. All patients were admitted to the high dependency unit (HDU) with 12.5% of patients receiving treatment that required a HDU level of care. Upon reaudit, 8 records were included with all patients admitted to HDU and the median day of discharge postoperative day 2. Notably, 37.5% patients were discharged on postoperative day 1 and a day of surgery admission (DOSA) process was implemented. Conclusions By reviewing a health board’s EVAR caseload, suitability for short stay EVARs can be assessed. Implementing an early discharge and DOSA process keeps care capacity available and may protect against nosocomial Covid-19.

Establishment of a New Abdominal Aortic Aneurysm Model in Rats by a Retroperitoneal Approach.

BackgroundConstructing an ideal model of abdominal aortic aneurysm (AAA) is of great significance to elucidate its complex pathogenesis. Therefore, we introduce a new and simple method to simulate human AAA and construct a rat AAA model through a retroperitoneal approach.MethodsForty healthy adult Sprague Dawley (SD) rats were randomly divided into a control group, elastase + calcium chloride group (PPE+CaCl2), elastase group (PPE), and elastase + beta aminopropionitrile group (PPE+BAPN) according to a male-female ratio of 1:1, with 10 rats in each group. A retroperitoneal approach was used to free the infrarenal abdominal aorta in all four groups. In the PPE + CaCl2 group, 0.1 ml of elastase (approximately 5 U) was perfused into the arterial cavity for 20 min, and 1.0 mol/L calcium chloride was infiltrated out of the arterial cavity for 10 min. In the PPE group, 0.1 mL of elastase (approximately 5U) was perfused into the arterial cavity for 20 min, and normal saline was infiltrated out of arterial cavity for 10 min; the PPE + BAPN group combined with 0.3% BAPN drinking water/day on the basis of PPE group; the control group was treated with saline instead of elastase and calcium chloride. Abdominal aortic specimens were collected after 4 weeks of feeding. The diagnostic criteria of AAA were 50% dilation of the abdominal aorta or rupture of the aneurysm at 4 weeks after the operation. Histopathology, immunohistochemistry, quantitative PCR (qPCR), western blotting assay, gelatine zymogram, and other methods were used.ResultsThe operation time of the four groups was controlled at approximately 40 min, and the success rate of the operation was 100%. Survival rate: Control Group (100%) = PPE Group (100%) > PPE + CaCl2 Group (90%) > PPE + BAPN Group (40%); Aneurysm formation rate: PPE + BAPN Group (100%) > PPE + CaCl2 Group (80%) > PPE Group (60%) > Control Group (0%); Aneurysm rupture rate: PPE + BAPN group (60%) > PPE + CaCl2 group (12.5%) > PPE group (0%);Inflammatory cells (macrophages, T cells, B cells, dendritic cells) infiltrated in different degrees in the PPE + CaCl2, PPE and PPE + BAPN groups. Vascular thickness, elastic fiber content, collagen fiber content, and vascular smooth muscle cell content in the PPE + CaCl2 group and PPE + BNPA group were significantly lower than those in Control group (P < 0.05). The content of elastic fibers and vascular smooth muscle cells in the PPE group were significantly lower than that in Control group (P < 0.05). The expression and activity of matrix metalloproteinase 2 (MMP2) and MMP9 in the PPE + CaCl2 group, PPE group, and PPE + BNPA group were significantly higher than those in the control group (P < 0.05).ConclusionsA new, simple, and reproducible rat AAA model can be constructed by a retroperitoneal approach. The pathological features of the three models are effective simulation of human AAA inflammatory cell infiltration, protease activity enhancement, and extracellular matrix destruction. The PPE+ CaCl2 model has the advantages of a high survival rate, high aneurysm formation rate, good stability, and reproducibility. It is an ideal animal model for studying the pathogenesis of AAA. The PPE + BAPN model can simulate the characteristics of spontaneous rupture of aneurysms. It is an ideal animal model to study the mechanism of AAA rupture.

Clinical Presentation, Operative Management, and Long-Term Outcome of Rupture After Previous Abdominal Aortic Aneurysm Repair

Late abdominal aortic aneurysm rupture (LAR) after open or endovascular repair is uncommon but life-threatening. In the present study, we characterized the presentation trends, intervention, and survival after LAR. We performed a single-center, retrospective study of patients who had undergone LAR repair from 2000 to 2020. The endpoints were 30-day mortality, major postoperative complications, and survival. We compared the outcomes between LAR managed with endovascular aortic aneurysm repair (EVAR; group I) vs open surgical repair (OSR; group II). Of 390 patients with infrarenal aortic aneurysm rupture, 40 (10%) had undergone prior aortic repair and comprised the LAR cohort (34 men; mean age, 78 years; initial EVAR for 29; initial OSR for 11). LAR had occurred despite reintervention in 13 patients (44%). Endoleaks had developed in 26 patients and were type I in 21 patients (72%), type III in 3 patients, (10%) and type II in 2 patients (3%). Ten patients (29%) were lost to follow-up. LAR after prior OSR was secondary to ruptured para-anastomotic pseudoaneurysms, which were managed with endovascular salvage in nine patients. The time to LAR was shorter after prior EVAR compared with after OSR (6 ± 4 vs 12 ± 4 years, respectively; P = .003). Treatment of LAR was EVAR for 27 patients (67%; group I) and OSR for 14 (35%; group II). EVAR was more frequent in the latter one half of the study period (Fig). In group I, fenestrated repair had been used for seven patients (26%). Salvage for the rest was feasible with EVAR, aortic cuffs, or limb extensions. The incidence of free rupture, time to treatment, 30-day mortality, and disposition was similar between the two groups. Those in group I had had less blood loss (660 vs 3000 mL; P < .001) and need for dialysis (0% vs 33%; P < .001) than those in group II. The median follow-up was 20 months (interquartile range, 6-45 months). The 1-, 3-, and 5-year survival was 76%, 52%, and 41%, respectively, and was similar between the two groups (28 vs 22 months; P = .92). LAR after abdominal aortic aneurysm repair has become increasingly common, likely resulting from the frequency of EVAR. Most LARs, including those occurring after previous OSR, can be now be salvaged with endovascular techniques with lower morbidity and mortality.

Mouse Abdominal Aortic Aneurysm Model Induced by Perivascular Application of Elastase.

Abdominal aortic aneurysm (AAA), although primarily asymptomatic, is potentially life-threatening as the rupture of AAA usually has a devastating outcome. Currently, there are several distinct experimental models of AAA, each emphasizing a different aspect in the pathogenesis of AAA. The elastase-induced AAA model is the second most used rodent AAA model. This model involves direct infusion or application of porcine pancreatic elastase (PPE) to the infrarenal segment of the aorta. Due to technical challenges, most elastase-induced AAA model nowadays is performed with the external application rather than an intraluminal infusion of PPE. The infiltration of elastase will cause degradation of elastic lamellae in the medial layers, resulting in the loss of aortic wall integrity and subsequent dilation of the abdominal aorta. However, one disadvantage of the elastase-induced AAA model is the inevitable variation of how the surgery is performed. Specifically, the surgical technique of isolating the infrarenal segment of the aorta, the material used for aorta wrapping and PPE incubation, the enzymatic activity of PPE, and the time duration of PPE application can all be important determinants that affect the eventual AAA formation rate and aneurysm diameter. Notably, the difference in these factors from different studies on AAA can lead to reproducibility issues. This article describes a detailed surgical process of the elastase-induced AAA model through direct application of PPE to the adventitia of the infrarenal abdominal aorta in the mouse. Following this procedure, a stable AAA formation rate of around 80% in male and female mice is achievable. The consistency and reproducibility of AAA studies using an elastase-induced AAA model can be significantly enhanced by establishing a standard surgical procedure.

EGR1 and KLF4 as Diagnostic Markers for Abdominal Aortic Aneurysm and Associated With Immune Infiltration.

BackgroundFormation and rupture of abdominal aortic aneurysm (AAA) is fatal, and the pathological processes and molecular mechanisms underlying its formation and development are unclear. Perivascular adipose tissue (PVAT) has attracted extensive attention as a newly defined secretory organ, and we aim to explore the potential association between PVAT and AAA.MethodsWe analyzed gene expression and clinical data of 30 PVAT around AAA and 30 PVAT around normal abdominal aorta (NAA). The diagnostic markers and immune cell infiltration of PVAT were further investigated by WGCNA, CIBERSORT, PPI, and multiple machine learning algorisms (including LASSO, RF, and SVM). Subsequently, eight-week-old C57BL/6 male mice (n = 10) were used to construct AAA models, and aorta samples were collected for molecular validation. Meanwhile, fifty-five peripheral venous blood samples from patients (AAA vs. normal: 40:15) in our hospital were used as an inhouse cohort to validate the diagnostic markers by qRT-PCR. The diagnostic efficacy of biomarkers was assessed by receiver operating characteristic (ROC) curve, area under the ROC (AUC), and concordance index (C-index).ResultsA total of 75 genes in the Grey60 module were identified by WGCNA. To select the genes most associated with PVAT in the grey60 module, three algorithms (including LASSO, RF, and SVM) and PPI were applied. EGR1 and KLF4 were identified as diagnostic markers of PVAT, with high accurate AUCs of 0.916, 0.926, and 0.948 (combined two markers). Additionally, the two biomarkers also displayed accurate diagnostic efficacy in the mice and inhouse cohorts, with AUCs and C-indexes all >0.8. Compared with the NAA group, PVAT around AAA was more abundant in multiple immune cell infiltration. Ultimately, the immune-related analysis revealed that EGR1 and KLF4 were associated with mast cells, T cells, and plasma cells.ConclusionEGR1 and KLF4 were diagnostic markers of PVAT around AAA and associated with multiple immune cells.