Saccular Abdominal Aortic Aneurysms: Patient Characteristics, Clinical Presentation, Treatment, and Outcomes in the Netherlands

Saccular and Fusiform Abdominal Aortic Aneurysms Treated With Endovascular Repair Differ in Presentation and Treatment Threshold: Analyses Using a National Clinical Database in Japan

BACKGROUND

Saccular abdominal aortic aneurysms (AAAs) are considered to be at higher risk of rupture than fusiform AAAs, but not much is known about the extent of this risk. Therefore, this study aimed to compare the rupture presentation between fusiform and saccular AAAs.

METHODS AND RESULTS

This is a retrospective cohort study on 27 290 patients who underwent primary endovascular repair for a degenerative AAA between 2016 and 2019, and who were registered in the National Clinical Database in Japan. At operation for nonruptured case, the aneurysm diameter was significantly smaller in saccular AAAs than in fusiform AAAs (median, 44.0 versus 51.0 mm; P<0.001). Similarly, aneurysm diameter at rupture was significantly smaller in saccular AAAs than in fusiform AAAs (median, 55.6 versus 68.0 mm; P<0.001). The likelihood of repair for rupture was significantly higher in saccular AAAs than in fusiform AAAs in the 40- to 54-mm diameter range, in which saccular morphology was found to be an independent risk factor for rupture against fusiform morphology by adjusting for sex and aneurysm diameter (odds ratio, 2.54 [95% CI, 1.75-3.69]). In addition, receiver-operating characteristic curve analysis revealed that the cutoff diameter to predict rupture was smaller in saccular AAAs than in fusiform AAAs (50.5 and 59.5 mm, respectively) based on the Youden index.

CONCLUSIONS

Saccular AAAs presented at smaller diameters than fusiform AAAs in patients with ruptured AAAs treated with endovascular aortic repair, which supports the idea that saccular AAAs should be treated at smaller diameters.

Narrative Review of Risk Assessment of Abdominal Aortic Aneurysm Rupture Based on Biomechanics-Related Morphology

CLINICAL IMPACT

Studies have shown that the biomechanical indicators based on multi-scale models are more effective in accurately assessing the rupture risk of AAA. To meet the need for clinical monitoring and rapid decision making, the typical morphological parameters associated with AAA rupture and their relationships with the mechanical environment have been summarized, which provide a reference for clinical preoperative risk assessment of AAA.

Clinical presentation, outcomes, and threshold for repair by sex in degenerative saccular vs fusiform aneurysms in the descending thoracic aorta

OBJECTIVE

Saccular-shaped thoracic aortic aneurysms (TAAs) are often treated at smaller diameters compared with fusiform TAAs, despite a lack of strong clinical evidence to support this practice. The aim of this study was to examine differences in presentation, treatment, and outcomes between saccular TAAs and fusiform TAAs in the descending thoracic aorta. We also examined the need for sex-specific treatment thresholds for TAAs.

METHODS

All Vascular Quality Initiative (VQI) patients undergoing thoracic endovascular aneurysm repair (TEVAR) for degenerative TAAs in the descending thoracic aorta from 2012 through 2022 were reviewed. Patients were stratified by urgency: emergent/urgent vs elective repairs (ruptured/symptomatic). Demographics, comorbidities, anatomical/procedural characteristics, and outcomes for fusiform TAAs and saccular TAAs were compared. Cumulative distribution curves were used to plot the proportion of patients who underwent emergent/urgent repair according to sex-stratified aortic diameter.

RESULTS

Among 655 emergent/urgent TEVARs, 37% were performed for saccular TAAs, whereas among 1352 elective TEVARs, 35% had saccular TAA morphology. Compared with fusiform TAAs, saccular TAAs more frequently underwent emergent/urgent (ruptured/symptomatic) TEVAR below the repair threshold in both females (<50 mm: 38% vs 10%; relative risk, 3.39; 95% confidence interval [CI], 2.04-5.70; P < .001), and males (<55 mm: 47% vs 21%; relative risk, 2.26; 95% CI, 1.60-3.18; P < .001). Moreover, among patients with emergent/urgent fusiform TAAs, females presented at smaller diameters compared with males, whereas there was no difference in preoperative aneurysm diameter among patients with saccular TAAs. Regarding outcomes, emergent/urgent treated saccular TAAs had similar postoperative outcomes and 5-year mortality compared with fusiform TAAs. Nevertheless, in the elective cohort, patients with saccular TAAs had similar postoperative mortality compared with those with fusiform TAAs, but a lower rate of postoperative spinal cord ischemia (0.7% vs 3.2%; P = .010). Furthermore, patients with saccular TAAs had a higher rate of 5-year mortality compared with their fusiform counterparts (23% vs 17%; hazard ratio, 1.53; 95% CI, 1.12-2.10; P = .010).

CONCLUSIONS

Patients with saccular TAAs underwent emergent/urgent TEVAR at smaller diameters than those with fusiform TAAs, supporting current clinical practice guideline recommendations that saccular TAAs warrant treatment at smaller diameters. Furthermore, these data support a sex-specific treatment threshold for patients with fusiform TAAs, but not for those with saccular TAAs. Although there were no differences in outcomes following TEVAR between morphologies in the emergent/urgent cohort, patients with saccular TAAs who were treated electively were associated with higher 5-year mortality compared with those with fusiform TAAs.

2022 ACC/AHA guideline for the diagnosis and management of aortic disease: A report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Brazilian Society for Angiology and Vascular Surgery guidelines on abdominal aortic aneurysm

The Brazilian Society of Angiology and Vascular Surgery, through the Guidelines Project, presents new Abdominal Aortic Aneurysm Guidelines, on the subject of care for abdominal aortic aneurysm patients. Its development prioritized descriptive guidelines, using the EMBASE, LILACS, and PubMed databases. References include randomized controlled trials, systematic reviews, meta-analyses, and cohort studies. Quality of evidence was evaluated by a pair of coordinators, aided by the RoB 2 Cochrane tool and the Newcastle Ottawa Scale forms. The subjects include juxtarenal aneurysms, infected aneurysms, and new therapeutic techniques, especially endovascular procedures. The current version of the guidelines include important recommendations for the primary topics involving diagnosis, treatment, and follow-up for abdominal aortic aneurysm patients, providing an objective guide for medical practice, based on scientific evidence and widely available throughout Brazil.

Correlation Between Aneurysm Dome Direction and Patient Outcomes Following Surgery for Ruptured Anterior Communicating Artery Aneurysms

Background Anterior communicating (Acom) artery aneurysms are the most common type of intracranial aneurysms. Despite the enormous advancements in the field of endovascular surgery for intracranial aneurysms, open surgical clipping of aneurysms remains the most durable management of Acom aneurysms. There have been various studies based on the clinical-radiological profile and outcome of open clipping for intracranial aneurysms, but the correlation of the direction of the aneurysm with the surgical outcome remains incompletely defined. Aim To analyze the correlation between the direction of the aneurysm dome and patient outcomes after surgery for ruptured Acom artery aneurysms. Materials and methods  CT angiography of the brain was done in all patients pre-operatively as part of the standard treatment protocol. Retrospective data was collected from an inter-departmental computerized database, which included the patient's details, history, investigations, a course in the hospital from admission to discharge, and an operative note by the surgeon. Prospective data was collected from patients with ruptured Acom artery aneurysms. We analyzed the relationship between the direction of the dome of the Acom aneurysm and preoperative, intraoperative, and postoperative variables. Results Of the 48 patients who underwent surgery for ruptured aneurysms, 34 (70.8%) were female and 14 (29.2%) were male. Among the 27 cases with anteriorly projecting aneurysms, 11 (40.7%) experienced postoperative complications. Of the five cases with posteriorly projecting aneurysms, two (40%) experienced postoperative complications. One-third of cases of the inferior dome direction and 10% of cases of the superior direction of the dome of aneurysm were also found to have postoperative complications. However, using the chi-square test, the association between postoperative complications and the direction of the aneurysm was determined to be statistically non-significant (p-value = 0.93). Conclusion The findings of our investigation indicate that aneurysms with superior projection exhibit the lowest likelihood of experiencing intraoperative rupture. However, it was seen that the outcome was influenced by dome projection throughout the three-month follow-up. The findings of our study indicate that aneurysms with a superior orientation exhibit the least likelihood of experiencing intraoperative rupture.

3D Visual Guide to Lines and Stripes in Chest Radiography

Chest radiography continues to be the first-line imaging modality for evaluation of the chest. Interpretation is based on the understanding of complex three-dimensional (3D) structural relationships, which are translated into a two-dimensional (2D) plane. These 2D projections form multiple "lines and stripes" on chest radiographs, representing the interfaces between the pulmonary parenchyma, pleura, and normal mediastinal structures. Given the subtlety of overlying tissue and the need to mentally synthesize planar images into three dimensions, structural relationships may be difficult to appreciate. An understanding of these relationships forms the basis of recognizing pathologic conditions and providing an accurate differential diagnosis, which can assist in targeted appropriate further workup. On a 2D radiograph, this means recognizing the normal lines and stripes as well as their appearance when effaced or displaced. Once this abnormality is identified, a focused differential diagnosis can be generated, which can be further narrowed on the basis of other factors, such as patient history or ancillary findings. Three-dimensional cinematic rendering is an innovative tool that can help radiologists grasp these anatomic relationships and discern subtle findings at radiography. This technique allows improved visualization of structures such as the pleura that are difficult to appreciate with traditional imaging modalities. The authors provide an updated review of lines and stripes on chest radiographs, using 3D cinematic rendering as a teaching tool. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Comparing maximum diameter and volume when assessing the growth of small abdominal aortic aneurysms using longitudinal CTA data: cohort study

BACKGROUND

Monitoring of abdominal aortic aneurysms (AAAs) is currently based on serial measurements of maximum aortic diameter. Additional assessment of aneurysm volume has previously been proposed to possibly improve growth prediction and treatment decisions. To evaluate the use of supplementing volume measurements, the authors aimed to characterise the growth distribution of AAA volume and to compare the growth rates of the maximum diameter and volume at the patient level.

METHODS

Maximum diameter and volume were monitored every 6 months in 84 patients with small AAAs, with a total of 331 computed tomographic angiographies (with initial maximum diameters of 30-68 mm). A previously developed statistical growth model for AAAs was applied to assess the growth distribution of volume and to compare individual growth rates for volume and for maximum diameter.

RESULTS

The median (25-75% quantile) expansion in volume was 13.4 (6.5-24.7) % per year. Cube root transformed volume and maximum diameter showed a closely linear association with a within-subject correlation of 0.77. At the surgery threshold maximum diameter of 55 mm, the median (25-75% quantile) volume was 132 (103-167) ml. In 39% of subjects, growth rates for volume and maximum diameter were equivalent, in 33% growth was faster in volume and in 27% growth was faster in maximum diameter.

CONCLUSION

At the population level, volume and maximum diameter show a substantial association such that the average volume is approximately proportional to the average maximum diameter raised to a power of three. At the individual level, however, in the majority of patient's AAAs grow at different pace in different dimensions. Hence, closer monitoring of aneurysms with sub-critical diameter but suspicious morphology may benefit from complementing maximum diameter by volume or related measurements.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate. Structure: Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

A Finite Element Based Analysis of a Hemodynamics Efficient Flow Stent Suitable for Different Abdominal Aneurysm Shapes

This research aimed to examine the impact of a proposed flow stent (PFS) on different abdominal artery shapes. For that purpose, a finite element-based model using the computational fluid dynamics (CFD) method is developed. The effect of PFS intervention on the hemodynamic efficiency is estimated by all of the significant criteria used for the evaluation of aneurysm occlusion and possible rupture; the flow velocity, pressure, wall shear stress (WSS), and WSS-related indices. Results showed that PFS intervention preserves the effects of high flow rate and decreases irregular flow recirculation in the sac of the aneurysm. The flow velocity decreases inside the aneurysm sac in the range of 55% to 80%. The time-averaged wall shear stress (TAWSS) was reduced from 42% to 53% by FPS deployment. The simulation results implies that PFS could heal an aneurysm efficiently with a mechanism that causes the development of thrombus and ultimately leads to aneurysm resorption.

Endovascular Aneurysm Repair With AFX Stent-Grafts or Tube Grafts for Sacciform Infrarenal Pathologies in a Narrow Aortic Anatomy

PURPOSE

The objective of this study was to compare the outcomes of patients treated with tube grafts and AFX stent-graft in the narrow infrarenal aortic anatomy.

MATERIALS AND METHODS

Patients with penetrating aortic ulcers (PAUs) or sacciform aneurysms of the infrarenal aorta and an aortic bifurcation diameter ≤20 mm who underwent endovascular aneurysm repair (EVAR) with bifurcated AFX or tube stent-grafts (TUBE) between 2012 and 2020 were included. Demographic data and the outcome of the AFX group were compared with the TUBE group. All morphological measurements in the preoperative and postoperative computed tomography scans were performed in the aortic centerline.

RESULTS

Fifty-one patients (female: 12/51; 29%; median age: 72 years [63, 77]) with a median follow-up of 10 (3, 39) months, were included, of whom 35/51 (69%) had PAUs and 11/51 were symptomatic (22%). The aortic bifurcation diameter was 17 mm (15, 18) with severe calcifications in 25/51 (49%). The distal aortic landing zone was longer in the TUBE group (9 mm vs 24 mm; p<0.001). The technical success was 96% with a median aneurysm shrinkage of 8% (3, 13), which was comparable between the groups (p=0.264). Periprocedural mortality, conversion to open surgery, myocardial infarction, and stroke were not observed. Two type Ia endoleaks (EL) and 2 type Ib EL occurred, all in the TUBE group (Type 1 EL; 19 vs 0%; p=0.013). The limb patency in the AFX group was 100%. One patient with a tube graft developed an infrarenal aortic thrombosis 40 months after the intervention. The reintervention rate in the TUBE group was higher (14 vs 0%; p=0.032) and included 3 aortic cuff implantations and 1 covered endovascular aortic reconstruction of aortic bifurcation (CERAB).

CONCLUSION

AFX stent-graft showed a lower rate of type I endoleaks and reinterventions in sacciform infrarenal aortic pathologies during the early and midterm follow-up.

AAA Revisited: A Comprehensive Review of Risk Factors, Management, and Hallmarks of Pathogenesis

Despite declining incidence and mortality rates in many countries, the abdominal aortic aneurysm (AAA) continues to represent a life-threatening cardiovascular condition with an overall prevalence of about 2-3% in the industrialized world. While the risk of AAA development is considerably higher for men of advanced age with a history of smoking, screening programs serve to detect the often asymptomatic condition and prevent aortic rupture with an associated death rate of up to 80%. This review summarizes the current knowledge on identified risk factors, the multifactorial process of pathogenesis, as well as the latest advances in medical treatment and surgical repair to provide a perspective for AAA management.

Thresholds for abdominal aortic aneurysm repair in Canada and United States

BACKGROUND

Previous studies have demonstrated significant geographic variations in the management of abdominal aortic aneurysms (AAA) despite standard guidelines. Differences in patient selection, operative technique, and outcomes for AAA repair in Canada versus United States were assessed.

METHODS

The Vascular Quality Initiative was used to identify all patients who underwent elective endovascular or open AAA repair between 2010 and 2019 in Canada and the United States. Demographic, clinical, and procedural characteristics were recorded and differences between countries were assessed using independent t test and χ² test. The primary outcome was the percentage of AAA repaired below recommended diameter thresholds (men, <5.5 cm; women, <5.0 cm). The secondary outcomes were in-hospital and 1-year mortality rates. Associations between region and outcomes were assessed using univariate/multivariate logistic regression and Cox proportional hazards analysis.

RESULTS

There were 51,455 US patients and 1451 Canadian patients who underwent AAA repair in Vascular Quality Initiative sites during the study period. There was a higher proportion of endovascular repairs in the United States (83.7% vs 68.4%; odds ratio [OR], 2.38; 95% confidence interval [CI], 2.13-2.63; P < .001). US patients had more comorbidities, including hypertension, congestive heart failure, chronic kidney disease, and prior revascularization. The percentage of AAA repaired below recommended thresholds was significantly higher in the United States (38.8% vs 15.2%; OR, 3.57; 95% CI, 3.03-4.17; P < .001). This difference persisted after controlling for demographic, clinical, and procedural characteristics (adjusted OR, 3.57; 95% CI, 2.63-4.17; P < .001). Factors that predicted AAA repair below recommended thresholds were US region (adjusted OR, 3.57; 95% CI, 3.03-4.17), male sex (adjusted OR, 2.89; 95% CI, 2.72-3.07), and endovascular repair (adjusted OR, 2.08; 95% CI, 1.95-2.21). The in-hospital mortality rate was low (1.0% vs 0.8%) and the 1-year rate mortality was similar between countries (hazard ratio, 0.96; 95% CI, 0.70-1.31; P = .79).

CONCLUSIONS

There are significant variations in AAA management between Canada and the United States. A greater proportion of US patients underwent AAA repair below the recommended diameter thresholds. This finding is partly driven by a higher percentage of endovascular repairs. Despite these differences, the perioperative and 1-year mortality rates are similar. Future studies should investigate reasons for these variations and quality improvement projects are needed to standardize care.

Abdominal aortic aneurysms

Abdominal aortic aneurysms (AAA) are prevalent among older adults and can cause significant morbidity and mortality if not addressed in a timely fashion. Their etiology remains the topic of continued investigation. Known causes include trauma, infection, and inflammatory disorders. Risk factors include cigarette smoking, advanced age, dyslipidemia, hypertension, and coronary artery disease. The pathophysiology of the disease is related to an initial arterial insult causing a cascade of inflammation and extracellular matrix protein breakdown by proteinases leading to arterial wall weakening. When identified early, aneurysms must be monitored for size, growth rate, and other factors which could increase the risk of rupture. Factors predisposing to rupture include size, active smoking, rate of growth, aberrant biomechanical properties of the aneurysmal sac, and female sex. Medical management includes the control of risk factors that may prevent growth, stabilize the aneurysm, and prevent rupture. Surgical management prevents rupture of high risk aneurysms, most commonly predicted by size. Less frequently, surgical management is required when the aneurysm has ruptured. Surgery involves a multidisciplinary approach to evaluate the patient's risk profile and to develop an operative plan involving either an endovascular or an open surgical repair. The patient must be carefully monitored post-operatively for complications and, in the case of endovascular repairs, for endoleaks. AAA management has evolved rapidly in recent years. Technical and technological advances have transformed the diagnosis and treatment of this disease.