Risk factors for aneurysm rupture in patients kept under ultrasound surveillance. UK Small Aneurysm Trial Participants

Effects of head position on internal and external carotid pressures in standing sedated horses

The effects of head position on internal carotid artery (ICA) and external carotid artery (ECA) pressures in standing sedated horses were evaluated in this study. The common carotid artery (CCA) was catheterized in 6 horses using an ultrasound-guided technique to facilitate placement of a pressure transducer within the ICA and ECA at the level of the guttural pouch. Transducer position was confirmed by endoscopic visualization. Mean arterial pressure (MAP) was measured with horses in both a head-up and head-down position. The dorsal metatarsal artery was catheterized as a control. Maintaining a head-up position decreased MAP in both the ICA (median: 75.21 mmHg) and ECA (median: 79.43 mmHg), relative to the head-down position (ICA median: 104.65 mmHg; ECA median: 102.26 mmHg). Mean arterial pressure in the dorsal metatarsal artery was not affected by head position. The head-up position resulted in lower arterial pressures in both the ICA and ECA (P = 0.03) compared with the head-down position in standing sedated horses.

Sex Differences in Rupture Risk and Mortality in Untreated Patients With Intact Abdominal Aortic Aneurysms

Background

Studies on intact abdominal aortic aneurysms mainly focus on treated patients, and data on untreated patients are sparse. The objective was to investigate sex differences among untreated patients regarding rupture and mortality rates and to determine predictors for these events. Sex‐specific causes of death were evaluated.

Methods and Results

All patients ≥40 years diagnosed from 2001 to 2015 (n=32 393) with intact abdominal aortic aneurysms were identified in national registries; 60% (n=19 569) were untreated. Comorbid loads, crude rupture, and mortality rates were assessed. Predictors of 5‐year rupture and mortality were analyzed in Cox models (sex, age, comorbidities, income, and marital status). The proportion of men and women with multiple comorbidities was similar. Within 5 years, 798 ruptures occurred (9.7% women versus 6.9% men, P<0.001). Ruptures were independently predicted by female sex (hazard ratio [HR], 1.23; 95% CI, 1.07–1.42; P=0.004), chronic obstructive pulmonary disease (HR, 1.36; 95% CI, 1.15–1.62; P<0.001), age (HR, 11.49; 95% CI, 5.68–23.25 for ≥80 years; P<0.001), and income (HR, 0.63; 95% CI, 0.53–0.75 for highest tertile; P<0.001). After 5 years, 56.5% women and 50.4% men were deceased. Mortality was not independently predicted by female sex. Rupture was the third most common cause of death (11.9% women versus 8.7% men; P<0.001). The median time‐to‐events was 2.8 years.

Conclusions

A considerable proportion of patients with intact abdominal aortic aneurysms in surveillance remain untreated. Despite surveillance algorithms, the healthcare system fails to prevent a high number of ruptures, especially among women. The time‐to‐event data highlight the urgency to develop more individualized surveillance.

Characteristics and outcomes of small abdominal aortic aneurysm rupture in the American College of Surgeons National Surgical Quality Improvement Program database

OBJECTIVE

The current guidelines recommend elective abdominal aortic aneurysm (AAA) repair at 5.5 cm for men and 5.0 cm for women. However, rupture can occur in patients with an aneurysm smaller than these size thresholds. In the present study, we investigated the proportion of AAAs that rupture at sizes less than elective operative thresholds and compared the outcomes of repair with those of aneurysms that had ruptured at a larger size. Our hypothesis was that the rupture of small AAAs carries mortality similar to that of rupture at larger sizes.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program targeted vascular files for open AAA repair and endovascular aneurysm repair (EVAR) were reviewed for all cases of ruptured AAAs (rAAAs) from 2011 to 2018. The patients were divided into two groups: those with small AAAs that had ruptured at a size less than the current size guidelines for elective repair and those with large AAAs that had ruptured at a size that had met the criteria for elective repair. Univariate analyses were conducted to compare the comorbidities and perioperative outcomes of infrarenal rAAA repair between the groups. Multivariable logistic regression was performed to examine the differences in mortality between small and large rAAAs after controlling for confounding variables.

RESULTS

Of the 1612 rAAA repairs, 167 (10.4%) were small rAAAs. The proportion of small rAAAs did not significantly change during the study period (P = .15). The large rAAA group was more likely to have juxtarenal or suprarenal aneurysms compared with the small rAAA group (27% vs 16%; P = .001). A comparison of infrarenal rAAAs only demonstrated that the mean small rAAA (n = 141) diameter was 4.1 cm in the women and 4.5 cm in the men compared with the large rAAAs (n = 1051), with a mean diameter of 7.1 cm in women and 8.3 cm in men (P < .01 for the women; P < .01 for the men). The patients in the small rAAA group had had a significantly lower body mass index but were more likely to be African American and to have hypertension. The small rAAA group was more likely to present without hypotension and to have undergone EVAR. The repair of small rAAAs was associated with lower bleeding and mortality and a shorter mean operative time but with more readmissions. Multivariable regression analysis demonstrated that size was not associated with outcome after adjusting for other variables.

CONCLUSIONS

Of all AAA repairs classified as treating rupture, 10% were for patients with small AAAs. Patients with small rAAA were less likely to present with hypotension and were more likely to have undergone EVAR. Further research into sac morphology and more sensitive imaging modalities might help identify small rAAAs at high risk of rupture that would benefit from elective repair.

Is there an immunogenomic difference between thoracic and abdominal aortic aneurysms?

BACKGROUND AND AIM

Aortic aneurysms most commonly occur in the infra-renal and proximal thoracic regions. While generally asymptomatic, progressive aneurysmal dilation can become rapidly lethal when dissection or ruptures occurs, highlighting the need for more robust screening. Abdominal aortic aneurysm (AAA) is more prevalent compared to thoracic aortic aneurysm (TAA). The true incidence of TAA is underreported due to the absence of population screening and the silent nature of TAA. To achieve the optimum survival rate in aortic aneurysms, knowledge of natural course, genetic association, and surgical results are needed to be applied with adequate medical treatment and careful selection of patients for operation. The purpose of this paper is to provide a comprehensive review of the literature on natural history, immunology, and genetic differences between thoracic and AAAs.

METHOD

The literature was collected from OVID, SCOPUS, and PubMed.

RESULTS

(1) AAA expands faster than TAA. AAA expands at approximately 0.3-0.45 cm annually, depending on various factors (advancing age, diameter of aorta, smoking etc.). TAA expands up to 0.3 cm annually in a non-bicuspid aortic valve patient. (2) An increase in Matrix metallopeptidase 1, 2, 9, 12, 14 led to degrading extracellular matrix of the aortic vessel wall. This significantly contributed to the pathogenesis in AAA, whereas overactive Transforming growth factor-beta played a major role in the pathogenesis of TAA.

CONCLUSION

In the future, genetic testing may be the gold standard for tackling the geneticheterogeneity of aneurysms, therefore, identifying at-risk individuals developing TAA andAAA earlier.

Linking Aortic Mechanical Properties, Gene Expression and Microstructure: A New Perspective on Regional Weakening in Abdominal Aortic Aneurysms

Background: Current clinical practice for the assessment of abdominal aortic aneurysms (AAA) is based on vessel diameter and does not account for the multifactorial, heterogeneous remodeling that results in the regional weakening of the aortic wall leading to aortic growth and rupture. The present study was conducted to determine correlations between a novel non-invasive surrogate measure of regional aortic weakening and the results from invasive analyses performed on corresponding ex vivo aortic samples. Tissue samples were evaluated to classify local wall weakening and the likelihood of further degeneration based on non-invasive indices.

Methods: A combined, image-based fluid dynamic and in-vivo strain analysis approach was used to estimate the Regional Aortic Weakness (RAW) index and assess individual aortas of AAA patients prior to elective surgery. Nine patients were treated with complete aortic resection allowing the systematic collection of tissue samples that were used to determine regional aortic mechanics, microstructure and gene expression by means of mechanical testing, microscopy and transcriptomic analyses.

Results: The RAW index was significantly higher for samples exhibiting lower mechanical strength (p = 0.035) and samples classified as low elastin content (p = 0.020). Samples with higher RAW index had the greatest number of genes differentially expressed compared to any constitutive metric. High RAW samples showed a decrease in gene expression for elastin and a down-regulation of pathways responsible for cell movement, reorganization of cytoskeleton, and angiogenesis.

Conclusions: This work describes the first AAA index free of assumptions for material properties and accounting for patient-specific mechanical behavior in relation to aneurysm strength. Use of the RAW index captured biomechanical changes linked to the weakening of the aorta and revealed changes in microstructure and gene expression. This approach has the potential to provide an improved tool to aid clinical decision-making in the management of aortic pathology.

Serum Lipid Oxidative Stress Products as Risk Factors Are the Candidate Predictive Biomarkers for Human Abdominal Aortic Aneurysms

This research was designed to determine the association of serum lipid peroxidation products with disease severity in patients with abdominal aortic aneurysm (AAA). In total, 76 pairs of AAA cases as well as matched controls were enrolled in our research using propensity score matching (PSM). And their malondialdehyde (MDA), lipid hydroperoxide (LPO), and glutathione peroxidase (GSH-Px) levels were also detected through enzyme-linked immunosorbent assay (ELISA). Additionally, the relative clinical data of enrolled participants were extracted. The serum biomarker concentrations were measured in 76 patients with AAAs (diameter between 30 and 54 mm, n = 54; diameter ≥55 mm, n = 22) and 76 control patients from observational cohort study. After PSM adjustment for clinical variables, including age, gender, heart ratio, body mass index, smoking, hypertension, diabetes mellitus, coronary heart disease, and stroke, the serum MDA and LPO among AAA cases were remarkably increased compared with those from the normal patients. Inversely, serum GSH-Px was significantly decreased in patients with AAA compared to the control group. Besides, the serum levels of MDA and LPO were independently associated with AAA risk. Typically, there was significantly positive correlation between MDA level and LPO level (R = 0.358) but negative correlation of MDA level with GSH-Px (R = -0.203) level in patients with AAA. Meanwhile, the area under the receiver operating characteristic curve was 0.965 when MDA was used to diagnose AAA, and the optimal threshold value was 0.242 nmol/mL. Moreover, serum MDA level was significantly increased in cases with rupture AAA compared to those in selective AAA cases. Logistic regression analysis suggested that a higher serum MDA level indicated an elevated risk of AAA rupture (odds ratio = 2.536; 95% CI: 1.037-6.203; P =0.041). Our present findings suggest that serum peroxidation contents were evidently changed among AAA cases. Serum MDA and LPO concentrations could be used to predict disease severity in patients with AAA. Moreover, serum MDA may serve as the candidate biomarker for diagnosis of AAA and accurate identification of increased risks of AAA rupture.

Influence of Sex on Outcomes After Thoracic Endovascular Repair for Type B Aortic Dissection

We aimed to investigate whether sex differences influence the clinical outcomes of patients who undergo thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). We retrospectively analyzed a prospectively maintained single-center cohort of patients with TBAD who underwent TEVAR between January 2010 and June 2017. We evaluated the in-hospital and long-term mortality and composite end point. Of the 913 patients, 793 (86.8%) were male and 120 (13.1%) were female. Compared to male patients, the female patients were older, more likely to have diabetes mellitus, but less likely to smoke or have hypertension. The proximal landing zone in 0 and 1 was higher in male patients (P = .023), who were more likely to require an aortic arch bypass. Endoleak, delirium, and ICU stay after stent-graft implantation were also more frequent in men. Sex factor was not associated with in-hospital or long-term mortality or the composite end point in the multivariable regression analyses and Cox regression model. The mean estimated survival time was similar between males and females (2462.9 ± 141.2 vs 2804.1 ± 117.4 days, P = .167) in the propensity score-matched cohort. Despite distinct characteristics between sex, there was no sex-related difference in long-term clinical outcomes after TEVAR for TBAD.

[Summary of the S3 guideline on abdominal aortic aneurysm from an anesthesiological perspective]

The current article is a summary of the 2018 revised S3 guideline on screening, diagnosis, therapy, and follow-up of the abdominal aortic aneurysm (AAA) from an anesthesiological point of view. It is the only interdisciplinary guideline that describes in particular the perioperative anesthesiological and intensive care management.

Impact of Chronic Kidney Disease on Aortic Disease-related Mortality: A Four-year Community-Based Cohort Study

Objective Despite advances in medicine, aortic diseases (ADs), such as aneurysm rupture and aortic dissection, remain fatal and carry extremely high mortality rates. Due to its low frequency, the risk of developing AD has not yet been fully elucidated. Chronic kidney disease (CKD) is an established risk factor for cardiovascular disease and mortality. The aim of the present study was to examine whether or not CKD is a risk for AD-related mortality in the general population. Methods We used a nationwide database of 554,442 subjects (40-75 years old) who participated in the annual "Specific Health Check and Guidance in Japan" checkup between 2008 and 2013. Results There were 131 aortic aneurysm and dissection deaths during the follow-up period of 2,123,512 person-years. A Kaplan-Meier analysis revealed that subjects with CKD had a higher rate of AD-related deaths than those without it. A multivariate Cox proportional hazard regression analysis demonstrated that CKD was an independent risk factor for AD-related death in the general population after adjusting for cardiovascular risk factors. The addition of CKD to cardiovascular risk factors significantly improved the C, net reclassification, and integrated discrimination indexes. Conclusion CKD is an additional risk for AD-related death, suggesting that CKD may be a target for the prevention and early identification of subjects at high risk for AD-related death in the general population.

Nationwide Study to Predict Colonic Ischemia after Abdominal Aortic Aneurysm Repair in The Netherlands

BACKGROUND

Colonic ischemia remains a severe complication after abdominal aortic aneurysm (AAA) repair and is associated with a high mortality. With open repair being one of the main risk factors of colonic ischemia, deciding between endovascular or open aneurysm repair should be based on tailor-made medicine. This study aims to identify high-risk patients of colonic ischemia, a risk that can be taken into account while deciding on AAA treatment strategy.

METHODS

A nationwide population-based cohort study of 9,433 patients who underwent an AAA operation between 2014 and 2016 was conducted. Potential risk factors were determined by reviewing prior studies and univariate analysis. With logistic regression analysis, independent predictors of intestinal ischemia were established. These variables were used to form a prediction model.

RESULTS

Intestinal ischemia occurred in 267 patients (2.8%). Occurrence of intestinal ischemia was seen significantly more in open repair versus endovascular aneurysm repair (7.6% vs. 0.9%; P < 0.001). This difference remained significant after stratification by urgency of the procedure, in both intact open (4.2% vs. 0.4%; P < 0.001) and ruptured open repair (15.0% vs. 6.2%); P < 0.001). Rupture of the AAA was the most important predictor of developing intestinal ischemia (odds ratio [OR], 5.9, 95% confidence interval [CI] 4.4-8.0), followed by having a suprarenal AAA (OR 3.4; CI 1.1-10.6). Associated procedural factors were open repair (OR 2.8; 95% CI 1.9-4.2), blood loss >1L (OR 3.6; 95% CI 1.7-7.5), and prolonged operating time (OR 2.0; 95% CI 1.4-2.8). Patient characteristics included having peripheral arterial disease (OR 2.4; 95% CI 1.3-4.4), female gender (OR 1.7; 95% CI 1.2-2.4), renal insufficiency (OR 1.7; 1.3-2.2), and pulmonary history (OR 1.6; 95% CI 1.2-2.2). Age <68 years proved to be a protective factor (OR 0.5; 95% CI 0.4-0.8). Associated mortality was higher in patients with intestinal ischemia versus patients without (50.6% vs. 5.1%, P < 0.001). Each predictor was given a score between 1 and 4. Patients with a score of ≥10 proved to be at high risk. A prediction model with an excellent AUC = 0.873 (95% CI 0.855-0.892) could be formed.

CONCLUSIONS

One of the main risk factors is open repair. Several other risk factors can contribute to developing colonic ischemia after AAA repair. The proposed prediction model can be used to identify patients at high risk for developing colonic ischemia. With the current trend in AAA repair leaning toward open repair for better long-term results, our prediction model allows a better informed decision can be made in AAA treatment strategy.

An update on the ovation abdominal stent graft for the treatment of abdominal aortic aneurysms: current evidence and future perspectives

Introduction: The Ovation stent-graft has presented satisfactory mid-term results in the management of abdominal aortic aneurysms (AAA). Its unique design with uncoupling of fixation and sealing and the lowest profile in the market has expanded the treatment in AAA with challenging neck anatomies and, especially, in the females presenting mostly with narrow iliac access vessels. Morever, a new design modification, the Ovation Alto was recently introduced in the Market, while certain off-label uses of the Ovation in treating either juxtarenal- or short-necked AAA have been proposed. Areas covered: Aim of this article was to present the current articles with the long-term results of the Ovation endograft and discuss the new developments and modifications in its use. Expert commentary: the Ovation stent-graft exhibits very satisfactory clinical long-term results in AAA treated within the instructions-for-use, expands significantly the treatment of AAA in females and overcomes reliably challenging anatomical issues of the infrarenal neck that would render these cases ineligible for treatment with any other endograft. Εxperience with the specific, unique technical features of Ovation as well as careful selection of patients and meticulous preoperative study of the AAA anatomy are key-elements to the successful performance of this endograft.

Vogl T, T. Grundmann R. Endovascular and Open Repair of Abdominal Aortic Aneurysm

BACKGROUND

This review presents the surgical indications, surgical procedures, and results in the treatment of asymptomatic and ruptured abdominal aortic aneurysms (AAA).

METHODS

An updated search of the literature on screening, diagnosis, treatment, and follow-up of AAA, based on the German clinical practice guideline published in 2018.

RESULTS

Surgery is indicated in men with an asymptomatic AAA ≥ 5.5 cm and in women, ≥ 5.0 cm. The indication in men is based on four randomized trials, while in women the data are not conclusive. The majority of patients with AAA (around 80%) meanwhile receive endovascular treatment (endovascular aortic repair, EVAR). Open surgery (open aneurysm repair, OAR) is reserved for patients with longer life expectancy and lower morbidity. The pooled 30-day mortality is 1.16% (95% confidence interval [0.92; 1.39]) following EVAR, 3.27% [2.7; 3.83] after OAR. Women have higher operative/interventional mortality than men (odds ratio 1.67%). The mortality for ruptured AAA is extremely high: around 80% of women and 70% of men die after AAA rupture. Ruptured AAA should, if possible, be treated via the endovascular approach, ideally with the patient under local anesthesia. Treatment at specialized centers guarantees the required expertise and infrastructure. Long-term periodic monitoring by mean of imaging (duplex sonography, plus computed tomography if needed) is essential, particularly following EVAR, to detect and (if appropriate) treat endoleaks, to document stable diameter of the eliminated aneurysmal sac, and to determine whether reintervention is necessary (long-term reintervention rate circa 18%).

CONCLUSION

Vascular surgery now offers a high degree of safety in the treatment of patients with asymptomatic AAA. Endovascular intervention is preferred.

Experimental Study of Rupture Pressure and Elasticity of Abdominal Aortic Aneurysms Found at Autopsy

BACKGROUND

Resistance and elasticity of normal and aneurysmal aorta walls are directly associated with this vessel's growth and rupture. This study aims to experimentally analyze the biomechanical behavior of aneurysmal specimens found at autopsy, comparing them with normal diameter aortas removed from age-matched donors.

METHODS

Thirty-eight human aortas (30 normal aortas; 8 infrarenal abdominal aortic aneurysms) were harvested during autopsy. An apparatus was built with a digital gauge, plastic tray, connections, and hoses that conducted fluid (air) from a pump through the system. Specimens were dissected, and a flexible balloon was introduced in each of them to avoid leakage. The specimens were fastened on the test tray, and activation of the air pump enhanced system pressure up to their rupture.

RESULTS

All 8 aneurysms and all 30 normal aortas specimens evolved to rupture under inflation pressures above 590 mm Hg (mean ± standard deviation = 1,035 ± 375 mm Hg) and 840 mm Hg (mean ± SD = 1,405 ± 342 mm Hg), respectively. In the aneurysm group, 25% of specimens did not rupture in their most dilated region. Percentage of increment in diameter was higher in normal aortas (mean ± SD = 0.2106 ± 0.144) than in aneurysms (mean ± SD = 0.093 ± 0.070).

CONCLUSIONS

In the present experiment, unruptured infrarenal abdominal aortic aneurysms could support high pressures nearly as much as nonaneurysmal abdominal aortas. In some specimens, the most dilated part of the aneurysm was not the most vulnerable under pressure. Normal aortas presented higher elasticity than aneurysms.

Impact of hyperuricemia on mortality related to aortic diseases: a 3.8-year nationwide community-based cohort study

Despite advances in medicine, aortic diseases (ADs) such as aortic dissection and aortic aneurysm rupture remain fatal with extremely high mortality rates. Owing to the relatively low prevalence of AD, the risk of AD-related death has not yet been elucidated. The aim of the present study was to examine whether hyperuricemia is a risk factor for AD-related mortality in the general population. We used a nationwide database of 474,725 subjects (age 40-75 years) who participated in the annual "Specific Health Check and Guidance in Japan" between 2008 and 2013. There were 115 deaths from aortic dissection and aortic aneurysm rupture during the follow-up period of 1,803,955 person-years. Kaplan-Meier analysis revealed that subjects with hyperuricemia had a higher rate of AD-related death than those without hyperuricemia. Multivariate Cox proportional hazard regression analysis demonstrated that hyperuricemia was an independent risk factor for AD-related death in the general population. The net reclassification index was improved by addition of hyperuricemia to the baseline model. This is the first report to demonstrate that hyperuricemia is a risk factor for AD-related death, indicating that hyperuricemia could be a crucial risk for AD-related death in the general population.

Aortic dissection and accelerated aneurysmal degeneration in a patient with giant cell arteritis

Giant cell arteritis (GCA) is associated with nonatheromatous aortic pathology. Here we present a case in which a 76-year-old woman with a biopsy-proven history of GCA and a previous repair of her ascending aortic aneurysm presents with an acute dissection of a 4-cm aneurysm in the descending thoracic aorta. It was treated using endovascular techniques. This report adds to a growing body of evidence that GCA is a risk factor for aortic dissection and nonatheromatous aortic aneurysms.

Predictors of Abdominal Aortic Aneurysm Risks

Computational biomechanics via finite element analysis (FEA) has long promised a means of assessing patient-specific abdominal aortic aneurysm (AAA) rupture risk with greater efficacy than current clinically used size-based criteria. The pursuit stems from the notion that AAA rupture occurs when wall stress exceeds wall strength. Quantification of peak (maximum) wall stress (PWS) has been at the cornerstone of this research, with numerous studies having demonstrated that PWS better differentiates ruptured AAAs from non-ruptured AAAs. In contrast to wall stress models, which have become progressively more sophisticated, there has been relatively little progress in estimating patient-specific wall strength. This is because wall strength cannot be inferred non-invasively, and measurements from excised patient tissues show a large spectrum of wall strength values. In this review, we highlight studies that investigated the relationship between biomechanics and AAA rupture risk. We conclude that combining wall stress and wall strength approximations should provide better estimations of AAA rupture risk. However, before personalized biomechanical AAA risk assessment can become a reality, better methods for estimating patient-specific wall properties or surrogate markers of aortic wall degradation are needed. Artificial intelligence methods can be key in stratifying patients, leading to personalized AAA risk assessment.

SPECT/CT imaging of apoptosis in aortic aneurysm with radiolabeled duramycin

The objective of this research was to estimate whether a ^[99mTc]duramycin probe can be used for apoptosis imaging in patients with aortic aneurysm (AA). Vascular smooth muscle cell (SMC) apoptosis has an important influence on AA development. Thus, non-invasive imaging of SMC apoptosis may be able to evaluate AA progress and risk stratification. SMCs were treated with hydrogen peroxide (H₂O₂; 200 μΜ) or culture medium as a control. Apoptosis was measured using flow cytometry and ^[99mTc]duramycin to detect the binding efficiency to apoptotic SMCs. C57/BL6 mice were administered angiotensin-II and beta-aminopropionitrile (BAPN) subcutaneously to establish an AA model, or saline for controls. Aortic specimens underwent pathological evaluation and their aortic diameters were measured after 6 weeks. Micro-SPECT/CT scanning of ^[99mTc]duramycin and ¹⁸F-FDG PET detection were performed. SMCs treated with H₂O₂ showed more apoptosis compared with the control group (67.2 ± 3.8% vs. 16.1 ± 0.6%, P < 0.01). The experimental group showed a high rate of AA formation (70%) compared with no AA formation in the control group. The average aorta diameter was higher and ^[99mTc]duramycin uptake at the AA site was higher in the experimental group compared with the control group. Compared with the normal aorta in the control group, AA in experiment group had more severe medial degeneration, elastic fiber reduction and fracture, and collagen degeneration. TUNEL staining verified the higher apoptosis rate at the AA site in experiment group compared with the control group (63.9 ± 3.7% in ascending AA, 66.4 ± 4.0% in thoracic AA, vs. 3.5 ± 0.3% in normal aorta, P < 0.01). ^[99mTc]Duramycin may be an effective probe to evaluate apoptosis in AA.

High prevalence of abdominal aortic aneurysms in patients with lung cancer

BACKGROUND

Lung cancer and abdominal aortic aneurysms (AAAs) possess multiple shared risk factors. Whereas both have screening guidelines in place, they vary in methodology despite having significant overlap in populations of patients screened.

METHODS

Our hospital system's Lung Cancer Program database was used to identify patients diagnosed with primary lung cancer within the past 15 years. Demographic and risk factor data were obtained, and patients' original positron emission tomography-computed tomography scans were re-read for measurements of the abdominal aorta (aortic diameter ≥3.0 cm). A cancer-free control group was obtained for comparison. Multilinear regression modeling was used to evaluate the independent associations of multiple variables on the presence of AAA.

RESULTS

Among 814 patients with primary lung cancer, 90 (11.1%; 95% confidence interval [CI], 8.9%-13.3%) had AAA compared with 4 of 200 (2%; 95% CI, 0.1%-3.9%) in the control group (P = .0001). Patients who smoked were more likely than nonsmokers to have AAA (11.9% [95% CI, 9.8-14.6] vs 2.2% [95% CI, 0.1-8.1]; P = .0021). In patients with AAA, 12% (11/90) had aneurysms that required treatment, and 76.6% had early-stage lung cancer. Women in our study also had a high prevalence of AAA (4.6%). Logistic regression analysis showed male sex (odds ratio [OR], 3.70; P <.001), increasing age (OR, 1.07 per year; P <.001), smoking amount (OR, 1.01 per pack-year; P = .004), and hypertension (OR, 2.30; P = .020) to be independent risk factors for AAA.

CONCLUSIONS

Patients with lung cancer have a high prevalence of AAA. If future studies can demonstrate a reduction in AAA mortality by screening for AAA and lung cancer simultaneously, it may prove worthwhile to extend the low-dose computed tomography scan through the lower abdomen in select patients.

Top 10 candidate aortic disease trials

Aortic pathologies such as aneurysm, dissection and trauma are relatively common and potentially fatal diseases. Over the past two decades, we have experienced unprecedented technical and medical developments in the field. Despite this, there is a great need, and great opportunities, to further explore the area. In this review, we have identified important areas that need to be further studied and selected priority aortic disease trials. There is a pressing need to update the AAA natural history and the role for endovascular AAA repair as well as to define biomarkers and genetic risk factors as well as influence of gender for development and progression of aortic disease. A key limitation of contemporary treatment strategies of AAA is the lack of therapy directed at small AAA, to prevent AAA expansion and need for surgical repair, as well as to reduce the risk for aortic rupture. Currently, the most promising potential drug candidate to slow AAA growth is metformin, and RCTs to verify or reject this hypothesis are warranted. In addition, the role of endovascular treatment for ascending pathologies and for uncomplicated type B aortic dissection needs to be clarified.

Feasibility and accuracy of a novel automated three-dimensional ultrasonographic analysis system for abdominal aortic aneurysm: comparison with two-dimensional ultrasonography and computed tomography

Background

Accurate measurement of the maximum aortic diameter (Dmax) is crucial for patients with abdominal aortic aneurysm (AAA). Aortic computed tomography (CT) provides accurate Dmax values by three-dimensional (3-D) reconstruction but may cause nephrotoxicity because of contrast use and radiation hazard. We aimed to evaluate the accuracy of a novel semi-automated 3-D ultrasonography (3-D US) system compared with that of CT as a reference.

Methods

Patients with AAA (n = 59) or individuals with normal aorta (n = 18) were prospectively recruited in an outpatient setting. Two-dimensional ultrasonography (2-D US) and 3-D US images were acquired with a single-sweep volumetric transducer. The analysis was performed offline with a software. Dmax and the vessel area of the Dmax slice were measured with 2-D US, 3-D US, and CT. The lumen and thrombus areas of the Dmax slice were also measured in 40 patients with intraluminal thrombus. Vessel and thrombus volumes were measured using 3-D US and CT.

Results

The Dmax values from 3-D US demonstrated better agreement (R² = 0.984) with the CT values than with the 2-D US values (R² = 0.938). Overall, 2-D US underestimated Dmax compared with 3-D US (32.3 ± 12.1 mm vs. 35.1 ± 12.0 mm). The Bland-Altman analysis of the 3-D US values, revealed better agreement with the CT values (2 standard deviations [SD], 2.9 mm) than with the 2-D US values (2 SD, 5.4 mm). The vessel, lumen, and thrombus areas all demonstrated better agreement with CT than with 2-D US (R² = 0.986 vs. 0.960 for the vessel, R² = 0.891 vs. 0.837 for the lumen, and R² = 0.977 vs. 0.872 for the thrombus). The thrombus volume assessed with 3-D US showed good correlation with the CT value (R² = 0.981 and 2 SD in the Bland-Altman analysis: 13.6 cm³).

Conclusions

Our novel semi-automated 3-D US analysis system provides more accurate Dmax values than 2-D US and provides precise volumetric data, which were not evaluable with 2-D US. The application of the semi-automated 3-D US analysis system in abdominal aorta assessment is easy and accurate.

Variation in Surgical Treatment of Abdominal Aortic Aneurysms With Small Aortic Diameters in the Netherlands

OBJECTIVE

To evaluate reasons to deviate from aneurysm diameter thresholds, and focus on the difference in how Dutch vascular surgical units (VSUs) perceive their deviation and their actual deviation.

BACKGROUND

Guidelines recommend surgical treatment for asymptomatic abdominal aortic aneurysms (AAAs) with a diameter of at least 55 mm for men and 50 mm for women. We evaluate reasons to deviate from these guidelines, and focus on the difference in how Dutch vascular surgical units (VSUs) perceive their deviation and their actual deviation.

METHODS

All patients undergoing elective AAA repair between 2013 and 2016 registered in the Dutch Surgical Aneurysm Audit (DSAA) were included. Surgery at diameters of <55 mm for men and <50 mm for women were considered guideline deviations. National deviation and hospital variation in deviation were evaluated over time. Questionnaires were distributed among all Dutch VSUs, inquiring for acceptable reasons for guideline deviation. VSUs were asked to estimate the guideline deviation percentage in their hospital which was then compared with their DSAA percentage.

RESULTS

In all, 9039 patients were included. In 15%, we found guideline deviation, varying from 2% to 40% between VSUs. Over time, 21 VSUs were identified with a lower percentage of deviation than the national mean each year and 8 VSUs with a higher percentage. 44/60 VSUs completed the questionnaire. Most commonly reported reasons to deviate were concomitant large iliac diameter (91%) and saccular aneurysm (82%). The majority of the VSUs (77%) estimated their guideline deviation to be <5%. Eleven VSUs (25%) estimated their deviation concordant with their DSAA percentage, but 75% of VSUs underestimated their deviation.

CONCLUSIONS

Dutch VSUs regularly deviate from the guidelines regarding aneurysm diameter, with variation between VSUs. Consensus exists amongst VSUs on acceptable reasons for guideline deviations; however, the majority underestimates their actual deviation percentage.

Long-Term Follow-Up of Men Invited to Participate in a Population-Based Abdominal Aortic Aneurysm Screening Program

A screening program for abdominal aortic aneurysm (AAA), inviting 65-year-old men, was started in Stockholm in 2010 (2.3 million inhabitants). The aim was to present a long-term follow-up of men participating in screening, as well as AAA repair and ruptures among nonparticipants. Demographics were collected for men with screening detected with AAA 2010 to 2016 (n = 672) and a control group with normal aortas at screening (controls, n = 237). Medical charts and regional Swedvasc (Swedish Vascular registry) data were analyzed for aortic repair for men born 1945 to 1951. Ultrasound maximum aortic diameter (AD) as well as Aortic Size Index (ASI) was recorded. Participation was 78% and prevalence of AAA was 1.2% (n = 672). Aortic repair rates correlated with high ASI and AD. During the study period, 22% of the AAA patients were treated with the elective repair; 35 men in surveillance died (5.2%), non-AAA-related causes (82.9%) dominated, followed by unknown causes among 4 (11.4%), and 2 (5.7%) possibly AAA-related deaths. Abdominal aortic aneurysm rupture rate was higher among nonparticipants (0.096% vs 0.0036%, P < .001). The low dropout rate confirms acceptability of follow-up after screening. The efficacy is shown by the much higher rupture rate among the nonparticipating men.

Pulmonary complications and survival after elective infrarenal endovascular abdominal aneurysm repair in patients with documented chronic obstructive pulmonary disease

BACKGROUND

Elective abdominal aortic aneurysm (AAA) repair is advocated in patients where risk of rupture exceeds the risks of peri-procedural morbidity and mortality. Chronic obstructive pulmonary disease (COPD) is a known risk factor for AAA and increased operative morbidity in general. Since literature on the correlation between the clinical classification of COPD and morbidity following endovascular infrarenal AAA repair (EVAR) is scarce, assessment per individual remains a challenge.

OBJECTIVE

To analyse the pulmonary and all-cause morbidity and mortality in patients with documented COPD and relate this to their GOLD classification.

METHODS

Sixty-eight patients with COPD, documented by a lung function test, who underwent elective EVAR between July 2002 and July 2018 were retrospectively reviewed. The primary endpoint was the incidence of 30-day pulmonary adverse events. Procedural characteristics, length of hospital stay, pulmonary and all-cause morbidity including major adverse events (MAEs) during follow-up and five-year survival divided per GOLD classification were the secondary endpoints.

RESULTS

There was no statistically significant difference in the incidence of pulmonary adverse events between GOLD I/II and GOLD III/IV patients. There was neither procedural nor 30-day mortality in either group. Through 30 days and 1 year, there was no difference in pulmonary and all-cause morbidity between groups. Three MAEs occurred in the GOLD I/II group versus 2 MAE in the GOLD III/IV group during the first postoperative year. The five-year survival was 66.0%, 60.9% and 61.9% for patients with GOLD I, GOLD II and GOLD III, respectively. Three of four GOLD IV died within the first year after EVAR.

CONCLUSION

EVAR can be safely performed in patients with COPD, with low 30-day morbidity and mortality rates. Although severe co-morbidity should be taken into account, EVAR seems to be justified in patients with COPD with a GOLD classification I, II or III. Further research should focus on optimising the pulmonary condition in patients selected for EVAR.

Association of hernia with subsequent aortic aneurysm in geriatric patients

OBJECTIVE

Although inguinal hernia and aortic aneurysm share similar pathogenic mechanisms of collagen and elastin destruction, their clinical association in geriatric patients is inconclusive. We assessed the association between hernia and the subsequent occurrence of aortic aneurysm in geriatric patients.

METHODS

Adult patients with hernias between 2000 and 2012 were identified from a longitudinal claims database of 1 million beneficiaries from Taiwan's National Health Insurance program, and a control group of patients without hernia were matched by propensity score in a ratio of 1:3. Patients previously diagnosed with aortic aneurysms or connective tissue diseases were excluded. Follow-up ended on December 31, 2013. The incidence rate of aortic aneurysm was compared between patients with hernia and those without. Cox proportional hazards models were used to estimate relative hazards.

RESULTS

After propensity score matching, there were 16,933 patients with hernia (aged 20-64 years: 10,326; ≥65 years: 6607) and 50,799 patients without hernia (aged 20-64: 30,978; ≥65: 19,821). Patients with hernia had a greater incidence rate and hazard ratio of aortic aneurysm than did patients without hernia (6.4 vs 4.8/10,000 person-years; adjusted subdistribution hazard ratio [sdHR], 1.34; 95% confidence interval [CI], 1.02-1.76; P = .03), especially for those aged ≥65 years (15.6 vs 10.4/10,000 person-years; adjusted sdHR, 1.44; 95% CI, 1.07-1.94; P = .01) In addition, geriatric patients with hernia were associated with a marginally greater risk of thoracic (adjusted sdHR, 1.66; 95% CI, 0.96-2.86) and abdominal (adjusted sdHR, 1.36; 95% CI, 0.96-1.94) aortic aneurysm rupture.

CONCLUSIONS

Geriatric patients with hernia were associated with a greater incidence of aortic aneurysm than were those without.

Dipeptidyl peptidase-4 is increased in the abdominal aortic aneurysm vessel wall and is associated with aneurysm disease processes

BACKGROUND

Abdominal aortic aneurysm (AAA) is a potentially life-threatening disease, and until today there is no other treatment available than surgical intervention. Dipeptidyl peptidase-4 (DPP4)-inhibitors, used clinically to treat type 2 diabetes, have in murine models been shown to attenuate aneurysm formation and decrease aortic wall matrix degradation, inflammation and apoptosis. Our aim was to investigate if DPP4 is present, active and differentially expressed in human AAA.

METHODS AND RESULTS

DPP4 gene expression was elevated in both media and adventitia of AAA tissue compared with control tissue, as measured by microarrays and qPCR, with consistent findings in external data. The plasma activity of DPP4 was however lower in male patients with AAA compared with age- and gender-matched controls, independently of comorbidity or medication. Immunohistochemical double staining revealed co-localization of DPP4 with cells positive for CD68, CD4 and -8, CD20, and SMA. Gene set enrichment analysis demonstrated that expression of DPP4 in AAA tissue correlated with expression of biological processes related to B- and T-cells, extracellular matrix turnover, peptidase activity, oxidative stress and angiogenesis whereas it correlated negatively with muscle-/actin-related processes.

CONCLUSION

DPP4 is upregulated in both media and adventitia of human AAA and correlates with aneurysm pathophysiological processes. These results support previous murine mechanistic studies and implicate DPP4 as a target in AAA disease.

LUCY results show females have equivalent outcomes to males following endovascular abdominal aortic aneurysm repair despite more complex aortic morphology

OBJECTIVE

Females remain underrepresented in studies of endovascular aneurysm repair (EVAR) owing to anatomic ineligibility for EVAR devices. The aim of the LUCY study is to explore the comparative safety and effectiveness of EVAR using a low-profile stent graft (Ovation; Endologix, Inc, Irvine, Calif) in females as well as males.

METHODS

The LUCY registry was a prospective, nonrandomized, multicenter study where patient enrollment was stratified by sex in a two-to-one ratio (male-to-female). Main outcomes were procedural data, 30-day major adverse events, device-related adverse events confirmed with contrast-enhanced computed tomography scans, secondary interventions, and hospital readmissions. Adverse events were adjudicated by a clinical events committee. Patients were followed at their 1-month and 1-year follow-up visits.

RESULTS

A total of 225 patients (76 females, 149 males) were enrolled at 39 U.S. centers. No statistically significant sex differences were observed in demographics or medical history. Females presented with smaller access vessels (6.2 vs 7.7 mm; P < .001), statistically smaller neck diameter (22 mm vs 23 mm; P = .001), similar neck angulation (11% vs 9% angulation >45°; P = .81), and smaller maximum abdominal aortic aneurysm (AAA) diameter (50 mm vs 53 mm; P = .01), however, these factors do not seem to be clinically significant. Technical success was 99%, and the median hospital stay was 1 day. The incidence of MAE through 30 days was 1.3% in females and 2.0% in males. There were no differences between sexes observed among the 30-day perioperative outcomes. The 30-day secondary intervention rate was 0.4%. The all-cause readmission rate through 30 days was 5.3% in females and 6.7% in males. There were no reports of limb occlusion or deaths within the first 30 days. At 1 year, there were no deaths in the female arm but nine deaths (6.0%) were observed in males, two of which were AAA related (1.3%). Through 1 year, there were eight type IA endoleaks (one female, seven males; P = .27) and three cases with limb occlusion (one female, two males). There were no reports of migration, AAA rupture, or surgical conversion through the end of follow-up.

CONCLUSIONS

Despite more complex aortic morphology in females than males, EVAR with a low-profile stent graft was associated with comparable procedural and perioperative outcomes through 1 year between the sexes.

Is the aortic size index relevant as a predictor of abdominal aortic aneurysm? A population-based prospective study: the Tromsø study

Objectives. The normal aortic diameter (AD) varies with gender, age and body surface area (BSA). The aortic size index (ASI) is defined as the AD divided by BSA. The primary aim of this study was to investigate if ASI is a predictor of development AAA, and to compare the predictive impact of ASI to that of the absolute AD. Design. Population-based prospective study including 4161 individuals (53.2% women) from the Tromsø study with two valid ultrasound measurements of the AD and no AAA at baseline (Tromsø 4, 1994). The primary outcome was AAA (AD ≥30 mm) in Tromsø 5 (2001). A secondary outcome was aortic growth of >5 mm over 7 years. Estimates of relative risk were calculated in logistic regression models. The main exposure variable was ASI. Adjustments were made for age, gender, smoking, body mass index, total and high-density lipoprotein (HDL) cholesterol, and hypertension. Results. In total, 124 incident AAAs (20% among women) were detected. In adjusted analyses, both ASI and AD were strong predictors of AAA, with similar results for men and women. Both ASI and AD were also significant predictors of aortic growth >5 mm. In comparison, AD was superior to ASI as a predictor of both endpoints. Conclusions. ASI was a significant predictor of both AAA development and aortic growth of >5 mm for both men and women, but not a better predictor of either outcomes compared to the AD. The role of ASI compared to the AD as a predictor of AAA development seems to be limited.

The Seed Coat Extract of Black Soybean Decreases Nicotine-Induced Vascular Fiber Degradation by Suppressing Matrix Metalloproteinase 2 Expression

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by weakening of vascular walls and progressive dilation of the abdominal aorta. Nicotine, the main component of tobacco, is reportedly associated with the development and rupture of AAA. It is desirable to attenuate the destructive effect of nicotine on vascular walls, using dietary food components. However, effective methods for preventing AAA progression using dietary food components remain unestablished. This study focuses on proanthocyanidins, well known for their potent antioxidant activity. We speculated that proanthocyanidins can suppress nicotine-induced weakening of vascular walls. To estimate the effect of black soybean seed coat extract (BSSCE), rich in proanthocyanidins, on nicotine-induced weakening of the aortic wall, mice were divided into four groups: the control diet and distilled water group (named C), BSSCE solution diet and distilled water group (named B), control diet and 0.5 mg/mL nicotine solution group (named CN), and BSSCE solution diet and 0.5 mg/mL nicotine solution group (named BN). Nicotine-induced degradation of elastin and collagen fibers were significantly suppressed in BN group. The positive areas for matrix metalloproteinase (MMP)-2 and oxidative stress in BN group were significantly decreased compared to those in CN group. These results suggest that proanthocyanidins-rich BSSCE can prevent the weakening of the aortic wall via inhibiting MMP-2 upregulation.

Primary Care Screening for Abdominal Aortic Aneurysm: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Ruptured abdominal aortic aneurysms (AAAs) have mortality estimated at 81%.

OBJECTIVE

To systematically review the evidence on benefits and harms of AAA screening and small aneurysm treatment to inform the US Preventive Services Task Force.

DATA SOURCES

MEDLINE, PubMed (publisher supplied only), Database of Abstracts of Reviews of Effects, and Cochrane Central Register of Controlled Trials for relevant English-language studies published through September 2018. Surveillance continued through July 2019.

STUDY SELECTION

Trials of AAA screening benefits and harms; trials and cohort studies of small (3.0-5.4 cm) AAA treatment benefits and harms.

DATA EXTRACTION AND SYNTHESIS

Two investigators independently reviewed abstracts and full-text articles and extracted data. The Peto method was used to pool odds ratios (ORs) for AAA-related mortality, rupture, and operations; the DerSimonian and Laird random-effects model was used to pool calculated risk ratios for all-cause mortality.

MAIN OUTCOMES AND MEASURES

AAA and all-cause mortality; AAA rupture; treatment complications.

RESULTS

Fifty studies (N = 323 279) met inclusion criteria. Meta-analysis of population-based randomized clinical trials (RCTs) estimated that a screening invitation to men 65 years or older was associated with a reduction in AAA-related mortality over 12 to 15 years (OR, 0.65 [95% CI, 0.57-0.74]; 4 RCTs [n = 124 926]), AAA-related ruptures over 12 to 15 years (OR, 0.62 [95% CI, 0.55-0.70]; 4 RCTs [n = 124 929]), and emergency surgical procedures over 4 to 15 years (OR, 0.57 [95% CI, 0.48-0.68]; 5 RCTS [n = 175 085]). In contrast, no significant association with all-cause mortality benefit was seen at 12- to 15-year follow-up (relative risk, 0.99 [95% CI 0.98-1.00]; 4 RCTs [n = 124 929]). One-time screening was associated with significantly more procedures over 4 to 15 years in the invited group compared with the control group (OR, 1.44 [95% CI, 1.34-1.55]; 5 RCTs [n = 175 085]). Four trials (n = 3314) of small aneurysm surgical treatment demonstrated no significant difference in AAA-related mortality or all-cause mortality compared with surveillance over 1.7 to 12 years. These 4 early surgery trials showed a substantial increase in procedures in the early surgery group. For small aneurysm treatment, registry data (3 studies [n = 14 424]) showed that women had higher surgical complications and postoperative mortality compared with men.

CONCLUSIONS AND RELEVANCE

One-time AAA screening in men 65 years or older was associated with decreased AAA-related mortality and rupture rates but was not associated with all-cause mortality benefit. Higher rates of elective surgery but no long-term differences in quality of life resulted from screening.

Statins Reduce Abdominal Aortic Aneurysm Growth, Rupture, and Perioperative Mortality: A Systematic Review and Meta-Analysis

Background

There are no recognized pharmacological treatments for abdominal aortic aneurysms (AAA), although statins are suggested to be beneficial. We sought to summarize the literature regarding the effects of statins on human AAA growth, rupture, and 30‐day mortality.

Methods and Results

We conducted a systematic review and meta‐analysis of randomized and observational studies using the Cochrane CENTRAL database, MEDLINE, and EMBASE up to June 15, 2018. Review, abstraction, and quality assessment were conducted by 2 independent reviewers, and a third author resolved discrepancies. Pooled mean differences and odds ratios with 95% confidence intervals were calculated using random effects models. Heterogeneity was quantified using the I² statistic, and publication bias was assessed using funnel plots. Our search yielded 911 articles. One case‐control and 21 cohort studies involving 80 428 patients were included. The risk of bias was low to moderate. Statin use was associated with a mean AAA growth rate reduction of 0.82 mm/y (95% confidence interval 0.33, 1.32, P=0.001, I²=86%). Statins were also associated with a lower rupture risk (odds ratio 0.63, 95% confidence interval 0.51, 0.78, P<0.0001, I²=27%), and preoperative statin use was associated with a lower 30‐day mortality following elective AAA repair (odds ratio 0.55, 95% confidence interval 0.36, 0.83, P=0.005, I²=57%).

Conclusions

Statin therapy may be associated with reduction in AAA progression, rupture, and lower rates of perioperative mortality following elective AAA repair. These data argue for widespread statin use in AAA patients.

Clinical Trial Registration

URL: http://www.crd.york.ac.uk. Unique identifier: CRD42017056480.

Let-7f: A New Potential Circulating Biomarker Identified by miRNA Profiling of Cells Isolated from Human Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a progressive vascular disease responsible for 1–4% of the deaths in elderly men. This study aimed to characterize specific microRNA (miRNA) expression in aneurysmal smooth muscle cells (SMCs) and macrophages in order to identify circulating miRNAs associated with AAA. We screened 850 miRNAs in aneurysmal SMCs, M1 and M2 macrophages, and in control SMCs isolated by micro-dissection from aortic biopsies using microarray analysis. In all, 92 miRNAs were detected and 10 miRNAs were selected for validation by qRT-PCR in isolated cells (n = 5), whole control and aneurysmal aorta biopsies (n = 13), and plasma from patients (n = 24) undergoing AAA (over 50 mm) repair matched to patients (n = 18) with peripheral arterial disease (PAD) with atherosclerosis but not AAA. Seven miRNAs were modulated similarly in all aneurysmal cells. The Let-7f was downregulated in aneurysmal cells compared to control SMCs with a significant lower expression in M1 compared to M2 macrophages (0.1 fold, p = 0.03), correlated with a significant downregulation in whole aneurysmal aorta compared to control aorta (0.2 fold, p = 0.03). Significant levels of circulating let-7f (p = 0.048) were found in AAA patients compared to PAD patients with no significant correlation with aortic diameter (R² = 0.03). Our study underlines the utility of profiling isolated aneurysmal cells to identify other miRNAs for which the modulation of expression might be masked when the whole aorta is used. The results highlight let-7f as a new potential biomarker for AAA.

Comprehensive Cardiac Rehabilitation as a Therapeutic Strategy for Abdominal Aortic Aneurysm

Abdominal aortic aneurysms (AAA) are referred to as “time bombs”. The only way to prevent AAA rupture is elective repair beforehand using surgical replacement or an endovascular procedure. Non-surgical strategies to prevent AAA expansion are under intense investigation. At each AAA stage, that is, occurrence, expansion, and rupture, the mechanisms and risk factors are different, as discussed in this review. Based on the mechanism and risk factors for AAA expansion, the most effective strategy against AAA expansion need to be identified, but so far none has. Exercise is known to be essential for preventing atherosclerosis related to the coexistence of AAA and CAD, but some doctors are hesitant to prescribe exercise programs to AAA patients given that BP elevation during exercise can cause AAA expansion or rupture. In our retrospective study and prospective study on the safety and effectiveness of exercise for AAA patients, the protective role of mild-moderate exercise against expansion of small AAA was clearly shown. The stability of AAA on exercise might be related to reduced inflammatory activity in the aortic wall, stabilized elevation in BP during exercise, increased aortic blood flow, upregulation of transforming growth factor-β1, moderated BMI and/or fat, or improved endothelial function. Until a revolutionary drug emerges that can regress AAA, cardiac rehabilitation remains the best strategy for preventing AAA expansion and rupture.

Plasma Desmosine and Abdominal Aortic Aneurysm Disease

Background

It is recognized that factors beyond aortic size are important in predicting outcome in abdominal aortic aneurysm (AAA) disease. AAA is characterized by the breakdown of elastin within the aortic tunica media, leading to aortic dilatation and rupture. The aim of this study was to investigate the association of plasma desmosine (pDES), an elastin‐specific degradation product, with disease severity and clinical outcome in patients with AAA.

Methods and Results

We measured pDES and serum biomarker concentrations in 507 patients with AAAs (94% men; mean age, 72.4±6.1 years; mean AAA diameter, 48±8 mm) and 162 control subjects (100% men; mean age, 71.5±4.4 years) from 2 observational cohort studies. In the longitudinal cohort study (n=239), we explored the incremental prognostic value of pDES on AAA events. pDES was higher in patients with AAA compared with control subjects (mean±SD: 0.46±0.22 versus 0.33±0.16 ng/mL; P<0.001) and had the strongest correlation with AAA diameter (r=0.39; P<0.0001) of any serum biomarker. After adjustment for baseline AAA diameter, pDES was associated with an AAA event (hazard ratio, 2.03 per SD increase [95% CI, 1.02–4.02]; P=0.044). In addition to AAA diameter, pDES provided incremental improvement in risk stratification (continuous net reclassification improvement, 34.4% [95% CI, −10.8% to 57.5%; P=0.09]; integrated discrimination improvement, 0.04 [95% CI, 0.00–0.15; P=0.050]).

Conclusions

pDES concentrations predict disease severity and clinical outcomes in patients with AAA.

Clinical Trial Registration

http://www.isrctn.com. Unique identifier: ISRCTN76413758.

Design and protocol of a comprehensive multicentre biobank for abdominal aortic aneurysms

INTRODUCTION

The pathophysiology and natural course of abdominal aortic aneurysms (AAAs) are insufficiently understood. In order to improve our understanding, it is imperative to carry out longitudinal research that combines biomarkers with clinical and imaging data measured over multiple time points. Therefore, a multicentre biobank, databank and imagebank has been established in the Netherlands: the 'Pearl Abdominal Aortic Aneurysm' (AAA bank).

METHODS AND ANALYSIS

The AAA bank is a prospective multicentre observational biobank, databank and imagebank of patients with an AAA. It is embedded within the framework of the Parelsnoer Institute, which facilitates uniform biobanking in all university medical centres (UMCs) in the Netherlands. The AAA bank has been initiated by the two UMCs of Amsterdam UMC and by Leiden University Medical Center. Participants will be followed during AAA follow-up. Clinical data are collected every patient contact. Three types of biomaterials are collected at baseline and during follow-up: blood (including DNA and RNA), urine and AAA tissue if open surgical repair is performed. Imaging data that are obtained as part of clinical care are stored in the imagebank. All data and biomaterials are processed and stored in a standardised manner. AAA growth will be based on multiple measurements and will be analysed with a repeated measures analysis. Potential associations between AAA growth and risk factors that are also measured on multiple time points can be assessed with multivariable mixed-effects models, while potential associations between AAA rupture and risk factors can be tested with a conditional dynamic prediction model with landmarking or with joint models in which linear mixed-effects models are combined with Cox regression.

ETHICS AND DISSEMINATION

The AAA bank is approved by the Medical Ethics Board of the Amsterdam UMC (University of Amsterdam).

TRIAL REGISTRATION NUMBER

NCT03320408.

Gender differences in outcomes after aortic aneurysm surgery should foster further research to improve screening and prevention programmes

Background Gender-related biases in outcomes after thoracic aortic surgery are an important factor to consider in the prevention of potential complications related to aortic diseases and in the analysis of surgical results. Methods The aim of this study is to provide an up-to-date review of gender-related differences in the epidemiology, specific risk factors, outcome, and screening and prevention programmes in aortic aneurysms. Results Female patients affected by aortic disease still have worse outcomes and higher early and late mortality than men. It is difficult to plan new specific strategies to improve outcomes in women undergoing major aortic surgery, given that the true explanations for their poorer outcomes are as yet not clearly identified. Some authors recommend further investigation of hormonal or molecular explanations for the sex differences in aortic disease. Others stress the need for quality improvement projects to quantify the preoperative risk in high-risk populations using non-invasive tests such as cardiopulmonary exercise testing. Conclusions The treatment of patients classified as high risk could thus be optimised before surgery becomes necessary by means of numerous strategies, such as the administration of high-dose statin therapy, antiplatelet treatment, optimal control of hypertension, lifestyle improvement with smoking cessation, weight loss and careful control of diabetes. Future efforts are needed to understand better the gender differences in the diagnosis, management and outcome of aortic aneurysm disease, and for appropriate and modern management of female patients.

Numerical Investigation of Turbulence in Abdominal Aortic Aneurysms

Computational fluid dynamics (CFD) is a powerful method to investigate aneurysms. The primary focus of most investigations has been to compute various hemodynamic parameters to assess the risk posed by an aneurysm. Despite the occurrence of transitional flow in aneurysms, turbulence has not received much attention. In this article, we investigate turbulence in the context of abdominal aortic aneurysms (AAA). Since the clinical practice is to diagnose an AAA on the basis of its size, hypothetical axisymmetric geometries of various sizes are constructed. In general, just after the peak systole, a vortex ring is shed from the expansion region of an AAA. As the ring advects downstream, an azimuthal instability sets in and grows in amplitude thereby destabilizing the ring. The eventual breakdown of the vortex ring into smaller vortices leads to turbulent fluctuations. A residence time study is also done to identify blood recirculation zones, as a recirculation region can lead to degradation of the arterial wall. In some of the geometries simulated, the enhanced local mixing due to turbulence does not allow a recirculation zone to form, whereas in other geometries, turbulence had no effect on them. The location and consequence of a recirculation zone suggest that it could develop into an intraluminal thrombus (ILT). Finally, the possible impact of turbulence on the oscillatory shear index (OSI), a hemodynamic parameter, is explored. To conclude, this study highlights how a small change in the geometric aspects of an AAA can lead to a vastly different flow field.

A large proportion of patients with small ruptured abdominal aortic aneurysms are women and have chronic obstructive pulmonary disease

Objective

In a population-based cohort of ruptured abdominal aortic aneurysms (rAAAs), our aim was to investigate clinical, morphological and biomechanical features in patients with small rAAAs.

Methods

All patients admitted to an emergency department in Stockholm and Gotland, a region with a population of 2.1 million, between 2009–2013 with a CT-verified rupture (n = 192) were included, and morphological measurements were performed. Patients with small rAAAs, maximal diameter (Dmax) ≤ 60 mm were selected (n = 27), and matched 2:1 by Dmax, sex and age to intact AAA (iAAAs). For these patients, morphology including volume and finite element analysis-derived biomechanics were assessed.

Results

The mean Dmax for all rAAAs was 80.8 mm (SD = 18.9 mm), women had smaller Dmax at rupture (73.4 ± 18.4 mm vs 83.1 ± 18.5 mm, p = 0.003), and smaller neck and iliac diameters compared to men. Aortic size index (ASI) was similar between men and women (4.1 ± 3.1 cm/m² vs 3.8 ± 1.0 cm/m²). Fourteen percent of all patients ruptured at Dmax ≤ 60 mm, and a higher proportion of women compared to men ruptured at Dmax ≤ 60 mm: 27% (12/45) vs. 10% (15/147), p = 0.005. Also, a higher proportion of patients with a chronic obstructive pulmonary disease ruptured at Dmax ≤ 60 mm (34.6% vs 14.6%, p = 0.026). Supra-renal aortic size index (14.0, IQR 13.3–15.3 vs 12.8, IQR = 11.4–14.0) and peak wall rupture index (PWRI, 0.35 ± 0.08 vs 0.43 ± 0.11, p = 0.016) were higher for small rAAAs compared to matched iAAAs. Aortic size index, peak wall stress and aneurysm volume did not differ.

Conclusion

More than one tenth of ruptures occur at smaller diameters, women continuously suffer an even higher risk of presenting with smaller diameters, and this must be considered in surveillance programs. The increased supra-renal aortic size index and PWRI are potential markers for rupture risk, and patients under surveillance with these markers may benefit from increased attention, and potentially from timely repair.

Impact on Quality of Life of Men with Screening-Detected Abdominal Aortic Aneurysms Attending Regular Follow ups: A Narrative Literature Review

OBJECTIVE

This study aimed to review, summarise, and assess the available evidence regarding the impact on the quality of life (QoL) of men undergoing screening for abdominal aortic aneurysm (AAA) and attending regular follow ups.

METHODS

PubMed, MEDLINE, CINAHL, and PsycINFO were used for searching. The search was performed from April to July 2016, with an update in February-March 2018. The quality of the studies was appraised with respective checklists from the Critical Appraisal Skills Programme. A narrative synthesis of the included studies was performed. The analysis included studies evaluating QoL in relation to one or more of the following concepts: physical function, psychological impact and social life in men undergoing AAA screening, but excluded studies evaluating QoL in AAA patients diagnosed outside a screening program.

RESULTS

The initial results from the search were 128 articles. Duplicates were removed, titles and abstracts were screened, and 22 full text articles were collected. Based on the inclusion criteria, 11 quantitative studies were included. Inferior quality of life among men with detected AAA was identified compared to those without the diagnosis and the general population in the included studies. The self-perceived health decreased over time for the participants with AAA. Assessments after surgery showed that the participants returned to similar health as before the screening. A wide variety of factors regarding the methodologies, designs, measurements, sample sizes, and the time for the assessment were noted in the included studies.

CONCLUSION

Quality of life is an important outcome for AAA screening and studies have been conducted in an attempt to address the imbalance between benefits and harm. However, it is still difficult to draw clear conclusions, possibly due to the heterogeneity of the original studies. Nevertheless, it is important to identify men with an AAA who develop conditions influencing their health and QoL in order to understand their care needs to further support them and improve their situation.

Clinical course of abdominal aortic aneurysms in Behçet disease: a retrospective analysis

Arterial aneurysms are rare manifestations of Behçet Disease (BD) with high morbidity and mortality. This study aimed to investigate the clinical course of BD patients with abdominal aortic aneurysms (AAA). We retrospectively searched charts of BD patients, followed up between 1988 and 2011, to identify those with AAA with at least 6-month clinical and radiological follow-up data. Chart review revealed 12 patients (11 males) with AAA amongst 1224 patients; follow-up data from 11 patients were available. The most common symptoms were lower back and abdominal pain. The only pre-treatment complication was a spontaneous rupture. All but one patient received corticosteroid and cyclophosphamide pulses for the induction, and corticosteroid and azathioprine for the maintenance treatment; one patient received only the maintenance treatment. Two patients had surgical graft interposition, without postoperative complications. Seven patients had endovascular stenting; five of them (71.4%) showed radiological regression after 32.5 (13.4-53.8) months, while four (57%) had clinical improvement after 11.8 (0.2-29.4) months. However, one non-responsive patient developed stent infection and exsanguinated during percutaneous drainage, and one patient developed femoral artery pseudo-aneurysm at the catheter insertion site. Another patient developed a new aneurysm under the maintenance treatment. Medical treatment alone yielded radiological regression in one of two patients. Current immunosuppressive, surgical or endovascular approaches can provide clinical and radiological improvements lately in BD patients with AAA. Furthermore, complication rates seem to be high with interventional approaches. These findings suggest an unmet need for safer alternative treatments.

Washington State abdominal aortic aneurysm-related mortality shows a steady decline between 1996 and 2016

OBJECTIVE

Management of abdominal aortic aneurysms (AAA) has undergone considerable advances over the last two decades. Our aim was to evaluate AAA-related mortality trends in Washington State over a 21-year period and to assess variation in AAA-related mortality by sex, race, and county over the same time period. We hypothesized that a significant decrease in AAA-related mortality in Washington State would be noted.

METHODS

Death certificate records were obtained from the Washington State Department of Health from 1996 to 2016. Records in which AAA was listed as an underlying or associated cause of death were selected for analysis. Age-standardized mortality rates for each year were calculated using the 2016 Washington State population as the standard. Mortality trends were compared by sex and race using linear regression. County-specific age-standardized ruptured AAA (rAAA) mortality rates were compared using a Kruskal-Wallis test.

RESULTS

Of the 1,014,039 deaths occurring in Washington State during the study period, 4438 (0.4%) had AAA listed as an underlying or associated cause of death (66.1% male; 94.8% white; mean age at death, 79.4 ± 9.3 years). In 64.1% of the cases, AAA was listed as the underlying cause of death. AAA-related mortality rates decreased by 62.1% over the 21 years from 5.8 to 2.2 deaths per 100,000. Notably, there was a statistically significant decrease in rAAA-related mortality rates (from 3.2 to 0.95 per 100,000, a decrease of 0.12 deaths/100,000/year; 95% confidence interval, 0.11-0.14; r² = 0.95). Men had a significantly steeper decrease in age-standardized AAA-related mortality rates with a 55% decrease (from 6.5 to 3.0 per 100,000) vs a 41% decrease (2.4 to 1.4 per 100,000) among women. Men were younger at the time of death than women (78.1 ± 9.4 years vs 81.9 ± 8.6 years, respectively; P < .001). Individuals who were white had a significantly steeper decrease in age-standardized AAA-related mortality rates with a 53% decrease (from 5.3 to 2.5 per 100,000) compared with a 13% decrease among individuals who were nonwhite (from 1.5 to 1.3 per 100,000). Age-standardized rAAA-related mortality rates varied by county (P < .001).

CONCLUSIONS

Age-standardized AAA-related mortality rate has decreased in Washington State between 1996 and 2016, with a notable decrease in the rAAA-related mortality rate. The decrease in AAA-related mortality rates varied by sex and race. Additionally, rAAA-related mortality rates differed between counties. These observations are a first step toward regional population assessments. Future work to understand the sources of variation can influence public health interventions on a state level.

Forecasting aortic aneurysm rupture: A systematic review of seasonal and atmospheric associations

BACKGROUND

Abdominal aortic aneurysms (AAAs) represent a significant burden of disease worldwide, and their rupture, without treatment, has an invariably high mortality rate. Whereas some risk factors for ruptured AAAs (rAAAs) are well established, such as hypertension, smoking, and female sex, the impact of seasonal and meteorologic variables is less clear. We systematically reviewed the literature to determine whether these variables are associated with rAAA.

METHODS

Review methods were according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We calculated pooled proportions and incidence rate ratios (IRRs) for the different months and seasons. Funnel plots were constructed to assess for publication bias. Given the poor methodologic quality of included studies, a sensitivity analysis was performed on better-quality studies, which scored 6 and above of 9 in the author-modified Newcastle-Ottawa Scale.

RESULTS

The pooled proportion of rAAA was highest in the autumn season (incidence rate, 26.6%; 95% confidence interval [CI], 25.6%-27.7%; I² = 15.4%), followed by winter (incidence rate, 26.2%; 95% CI, 24.1%-28.2%; I² = 72.4%), and lowest in summer (incidence rate, 21.1%; 95% CI, 19.3%-23.0%; I² = 70.4%). The IRRs of rAAA were -6.9% (95% CI, -9.8% to -3.9%), -19.5% (95% CI, -22% to -16.8%), +10.5% (95% CI, 7.2%-13.9%), and +18.1% (95% CI, 15%-22%) in spring, summer, autumn, and winter compared with the remaining seasons, respectively (all P < .0001), thus affirming existence of seasonal variation. The pooled proportion of rAAA was highest in December (incidence rate, 8.9%; 95% CI, 7.1%-10.9%; I² = 54.5%) but lowest in July (incidence rate, 5.7%; 95% CI, 4.2%-7.3%; I² = 54.5%). The IRR was significantly the highest in January (IRR, 1.14; 95% CI, 1.01-1.29; P = .031) but lowest in July (IRR, 0.75; 95% CI, 0.65-0.87; P < .0001). There is also some evidence for a possible association with atmospheric pressure. Associations with temperature and daylight hours, however, are at best speculative.

CONCLUSIONS

Autumn and winter are significantly associated with a higher incidence of rAAAs, and autumn is associated with the highest rupture incidence of all the seasons. However, the inability to appropriately control for other confounding factors known to increase the risk of AAA rupture precludes any additional recommendations to alter current provision of vascular services on the basis of these data.

Spatial Distribution of Abdominal Aortic Aneurysm Surface Expansion and Correlation With Maximum Diameter and Volume Growth

BACKGROUND

Abdominal aortic aneurysm (AAA) growth rate, measured as maximum diameter (Dmax) change over time, is used as a surrogate marker of rupture risk. However, AAA expansion presents significant spatial variability. We aim to record the spatial distribution of regional wall surface expansion.

METHODS

Thirty AAAs were retrospectively studied. Each AAA had one baseline and at least one follow-up computed tomography scan. Three-dimensional AAA models were reconstructed, and change in Dmax and total aneurysm volume was recorded to calculate annual growth rates. Regional surface growth was quantified using the VascForm algorithm, which is based on nonrigid point cloud registration and iterative closest point analysis. Maximum and average surface growths were calculated and correlated with the diameter/volume growth rates. Furthermore, to identify potential correlation between maximum thrombus (intraluminal thrombus) thickness and maximum surface growth, as well as between peak wall stress (PWS) and surface growth, their colocalization was examined.

RESULTS

The median average annual surface growth was 6% (0%-28%), and the maximum surface growth 24% (11%-238%). There was strong evidence of a moderate correlation between Dmax and average as well as maximum surface growth. Regarding volumes, there was strong evidence of a very strong association with average surface growth rate and a moderate association with maximum surface growth rate (rho: 0.91, P < 0.001; rho: 0.7, P < 0.001, respectively). In 51.6% of the follow-ups, maximum surface growth occurred away from Dmax site. Sixteen cases presented maximum surface growth away and fifteen at the region of maximum initial intraluminal thrombus thickness. AAAs in the former group had significantly thinner initial intraluminal thrombus thickness (11.3 vs 19.5 mm, P < 0.001) than those in the latter. Apart from a single case, maximum surface growth did not occur at the PWS region.

CONCLUSIONS

More than half of the lesions display maximum growth away from Dmax, suggesting that a more accurate method of analyzing AAA growth needs to be established in clinical practice that will take into account local surface growth.