Systematic review and meta-analysis of the prevalence of abdominal aortic aneurysm in Asian populations

OBJECTIVE

The prevalence of abdominal aortic aneurysms (AAAs) is well reported in Western countries and AAA screening programs are well-established. However, although individual studies have reported that the prevalence of AAAs is lower in Asian populations, high-quality data on the prevalence of AAA in Asians are relative lacking. The present study aimed to systematically synthesize the data available in the literature and report the prevalence of AAAs in Asians.

METHODS

An electronic search was performed using two major databases (PubMed and EMBASE) with no limitations imposed on the year of publication. The review conformed to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Studies that reported the prevalence of AAAs in Asians were selected, and the population characteristics, AAA definition, method of screening, target population, and total number of patients screened were recorded.

RESULTS

Our search yielded 157 unique articles. After a full-text review, 17 articles were included in the present study. All 17 studies of fair quality. The overall AAA prevalence was 1.30% (95% confidence interval [CI], 1.01%-1.59%) in Asian populations. The prevalence of AAAs was 2.56% (95% CI, 1.81%-3.31%) in Asian populations selected for cardiovascular risk factors and 0.61% (95% CI, 0.37%-0.85%) in Asian populations not selected for cardiovascular risk factors.

CONCLUSIONS

The prevalence of AAAs in the general Asian population is low. However, the prevalence in Asian populations selected for cardiovascular risk factors approaches the prevalence of AAAs in Western populations. As such, screening for AAAs in carefully selected Asian male populations with cardiovascular risk factors could potentially yield benefits. Opportunistic screening for AAAs during ultrasound examination of the abdomen or transthoracic echocardiography for other indications could also be considered. However, further studies are needed to evaluate the potential benefits of screening for AAAs in carefully selected Asian populations.

Early Detection of Undiagnosed Abdominal Aortic Aneurysm and Sub-Aneurysmal Aortic Dilatations in Patients with High-Risk Coronary Artery Disease: The Value of Targetted Screening Programme

INTRODUCTION

Abdominal aortic aneurysm (AAA) and coronary artery disease (CAD) share common risk factors. The objective of this study was to determine the prevalence of undiagnosed AAA in patients with angiographically diagnosed significant CAD.

PATIENTS AND METHODS

Male patients aged 50 years and above (including indigenous people) with angiographically diagnosed significant CAD in the recent one year were screened for AAA. Standard definition of abdominal aortic aneurysm and CAD was used. All new patients were followed up for six months for AAA events (ruptured AAA and AAA-related mortality).

RESULTS

A total of 277 male patients were recruited into this study. The total prevalence of undiagnosed AAA in this study population was 1.1% (95% CI 0.2-3.1). In patients with high-risk CAD, the prevalence of undiagnosed AAA was 1.7% (95% CI 0.3-4.8). The detected aneurysms ranged in size from 35.0mm to 63.8mm. Obesity was a common factor in these patients. There were no AAA-related mortality or morbidity during the follow-up. Although the total prevalence of undiagnosed AAA is low in the studied population, the prevalence of sub-aneurysmal aortic dilatation in patients with significant CAD was high at 6.6% (95% CI 3.9-10.2), in which majority were within the younger age group than 65 years old.

CONCLUSION

This was the first study on the prevalence of undiagnosed AAA in a significant CAD population involving indigenous people in the island of Borneo. Targeted screening of patients with high-risk CAD even though they are younger than 65 years old effectively discover potentially harmful asymptomatic AAA and sub-aneurysmal aortic dilatations.

Point-of-care ultrasound for the acute abdomen in the primary health care

Point-of-care ultrasound (POCUS) is a focused examination, which is performed and interpreted at the bedside by the treating physician answering a specific clinical question. It is currently utilized as an essential adjunct to physical examination in many medical specialties. Recent advances in technology have made POCUS machines portable, affordable, and could be used with minimal training even by nonradiologists. This review aims to cover the fundamental physics of POCUS and its applications for diagnosing the acute abdomen in the primary health care including the most common causes encountered by family physicians. These are acute appendicitis, acute cholecystitis, renal colic, ectopic pregnancy, acute diverticulitis, bowel obstruction, and abdominal aortic aneurysm. We hope to encourage primary care physicians to incorporate POCUS in their routine clinical practice. We also highlight challenges encountered when using POCUS in the primary health care including limited availability and the need for proper training. Furthermore, we review the POCUS results when performed by primary health-care physicians. Integrating POCUS in primary health care empowers primary health-care physicians to provide high-quality, safe, and cost-effective care to the patients.

Establishment of Novel Murine Model showing Vascular Inflammation-derived Cognitive Dysfunction

Inflammation is a critical feature of aging and its related diseases, including cardiovascular diseases. Recent epidemiological studies demonstrated that abdominal aortic aneurysm (AAA), an aging-related vascular pathological condition, is associated with cognitive decline. However, the underlying mechanism, especially the role of vascular inflammation, is largely unknown because of lack of an available animal model. In this study, we examined whether vascular inflammation affects synaptic and cognitive dysfunction, using an AAA mouse model. In young (3 months) and middle-aged (12 months) C57BL/6J mice, AAA was induced by angiotensin II infusion with calcium chloride application. After 4 weeks of induction, aortic diameter was significantly increased and excessive Mac3-positive inflammatory cells infiltrated the destroyed aorta in middle-aged mice. AAA-induced middle-aged mice further exhibited cognitive impairment. Neuronal loss was observed in the CA3 region of the hippocampus. IBA1/MHCII-double-positive microglia activation was also seen in the hippocampus, suggesting that vascular inflammation drives neuroinflammation and subsequent cognitive dysfunction. Furthermore, we found that senescence-accelerated mice prone 8 exhibited robust AAA formation and a marked decrease of cognitive and synaptic function in the hippocampus mediated by inflammation. In conclusion, this novel murine model convincingly suggested the occurrence of vascular inflammation-derived cognitive dysfunction.

Aortic Aneurysm as a Complication of Myeloperoxidase-antineutrophil Cytoplasmic Antibody-associated Vasculitis

Myeloperoxidase-antineutrophil cytoplasmic antibody-associated vasculitis (MPO-AAV) does not usually involve large vessels, such as the aorta. However, we experienced three cases having an aortic aneurysm as a complication of MPO-AAV with renal insufficiency. In one patient it involved the onset of descending aortic dissection during treatment for MPO-AAV; another two patients had an abdominal aortic aneurysm at the time of our diagnosis of MPO-AAV. Although we found no pathological evidence in our patients, MPO-AAV might result in large vessel inflammation. Therefore, we suggest that patients with MPO-AAV should be examined by computed tomography scan to check for the presence of an aortic aneurysm.

Non-visualized aorta in abdominal aortic aneurysm screening: Screening outcomes and the influence of subject and programme characteristics

Objectives To compare abdominal aortic aneurysm screening outcomes of men with non-visualized aorta at original scan with subsequent scans and to determine predictors of non-visualized aorta. Methods In the Northern Ireland Abdominal Aortic Aneurysm screening programme, outcomes (discharge, annual surveillance, three-monthly surveillance, or vascular referral) and patient and programme characteristics (age, deprivation quintile, family history, technician experience, and screening location) for men with non-visualized aorta were investigated at original scan, and first and second rescans. Results Non-visualized aorta proportions were 2.9, 11.4, and 4.7% at original, first, and second rescan, respectively. There were no differences in screening outcomes between scanning stages (98.4, 97.6, and 97.4% <3 cm). There were 42 men (0.13%) with aortas ≥5.5 cm at original scan, but none at first and second rescan. A significantly greater proportion with non-visualized aorta were from more deprived (5.0%) than less deprived areas (1.7%). Deprivation quintile and staff role were significant independent non-visualized aorta predictors at original scan, and staff role at first rescan. Men from less deprived areas were three times as likely to have aortas visualized than those from more deprived areas (OR = 3.0, CI = 2.4-3.8) at original scan. A man scanned by screening technician compared with lead sonographer was 51% less likely to have aorta visualized at original scan and 94% less likely at first rescan. Conclusions The risk of abdominal aortic aneurysm in men with non-visualized aorta on first or subsequent rescans is no more than for those with visualized aorta on original scanning. Men from deprived areas are much more likely to have non-visualized aorta at original scan.

Chronic Kidney Disease Is Positively and Diabetes Mellitus Is Negatively Associated with Abdominal Aortic Aneurysm

BACKGROUND AND AIMS

Chronic kidney disease (CKD) and diabetes mellitus (DM) are considered as risk factors for cardiovascular diseases. The purpose of this study was to clarify the relationship of CKD and DM with the presence of abdominal aortic aneurysm (AAA).

METHODS

We enrolled 261 patients with AAA (AAA+) and age-and-sex matched 261 patients without AAA (AAA-) at two hospitals between 2008 and 2014, and examined the association between the risk factors and the presence of AAA. Furthermore, in order to investigate the prevalence of AAA in each group, we enrolled 1126 patients with CKD and 400 patients with DM.

RESULTS

The presence of CKD in patients with AAA+ was significantly higher than that in patients with AAA- (AAA+; 65%, AAA-; 52%, P = 0.004). The presence of DM in patients with AAA+ was significantly lower than that in patients with AAA- (AAA+; 17%, AAA-; 35%, P < 0.001). A multivariate logistic regression analysis demonstrated that hypertension, ischemic heart disease and CKD were independent determinants, whereas, DM was a negatively independent determinant, for the presence of AAA. The prevalence of AAA in patients with CKD 65 years old and above was 5.1%, whereas, that in patients with DM 65 years old and above was only 0.6%.

CONCLUSION

CKD is a positively associated with the presence of AAA. In contrast, DM is a negatively associated with the presence of AAA in Japanese population.

Primary aortoduodenal fistula with a history of distal gastrectomy

Case

A 69‐year‐old man was transferred to our hospital because of an aortoduodenal fistula with hematemesis and pre‐shock vital signs. He had a history of alcoholism, malnutrition, and distal gastrectomy and Billroth I reconstruction. Endovascular aneurysm repair was successfully carried out; however, the presence of comorbidities affected further radical treatment.

Outcome

The patient survived for 2 months postoperatively.

Conclusion

Endovascular aneurysm repair is a useful first‐line treatment for high‐risk aortoduodenal fistula patients; however, it requires improvement for long‐term outcomes in complicated high‐risk cases.