Fate of the ectatic infrarenal aorta: expansion rates and outcomes

Editor's Choice - Risk of Rupture and All Cause Mortality of Abdominal Aortic Ectasia: A Systematic Review and Meta-Analysis

OBJECTIVE

To clarify the natural history of abdominal aortic ectasia (AAE) measuring 25 - 29 mm in maximum diameter, and to determine the optimal follow up based on the growth, risk of rupture, and overall mortality of AAE.

DATA SOURCES

MEDLINE, Web of Science Core Collection, and Google Scholar.

REVIEW METHODS

This was a systematic review and meta-analysis of AAE in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. MEDLINE, Web of Science Core Collection, and Google Scholar were searched, with the help of a health sciences librarian, up to 11 August 2021. Studies with longitudinal outcomes of AAE (prevalence, annual growth rate, aneurysmal enlargement, rupture, aneurysm related death, and all cause mortality) were included. Meta-analyses were conducted with a random effects model RESULTS: Twelve studies describing a total of 8 369 patients were eligible. The prevalence at population based settings was 3.2% (95% confidence interval [CI] 2.4 - 4.0); annual growth rate was 0.82 mm/year (95% CI 0.20 - 1.45). The estimated risks of aortic diameters exceeding 30 mm and 55 mm in five years were 45.0% (95% CI 28.5 - 61.5) and 0.3% (95% CI 0 - 0.6) respectively, while those beyond five years were 70.2% (95% CI 46.9 - 93.6) and 5.2% (95% CI 2.2 - 8.2). The rates of rupture and aneurysm related death were minimal until five years (0.1% and 0.1%, respectively) and beyond (0.4% and 0.2%, respectively). Overall mortality was 7.5% (95% CI 3.9 - 11.0) and 17.3% (95% CI 9.5 - 25.1) up to and beyond five years. Overall mortality from three studies showed no statistical difference between AAE and aneurysms (hazard ratio 0.62, 95% CI 0.32 - 1.21; p = .16). Cancer (35.0%) and cardiovascular diseases (31.9%) were major causes of death.

CONCLUSION

AAE carries minimal risk of aneurysm related lethal events during the first five years, but a similar overall mortality risk as abdominal aortic aneurysm. Cancer and cardiovascular diseases are leading causes of death in patients with AAE.

Abdominal aortic diameter and cardiovascular status in patients with idiopathic retroperitoneal fibrosis

Although much debated, an exaggerated inflammatory response to advanced atherosclerosis has been implicated in the pathogenesis of idiopathic retroperitoneal fibrosis (RPF). Clinical presentation, infrarenal abdominal aortic diameter and RPF mass thickness were retrospectively analyzed in 166 patients with idiopathic RPF seen at our referral center between April 1998 and December 2019. Patients were stratified to their infrarenal abdominal aortic diameter at presentation (i.e., non-ectatic [< 25 mm]; ectatic [25-29 mm]; and aneurysmal [≥ 30 mm]) to compare characteristics across groups with an undilated or dilated aorta. Ectatic or aneurysmal aortic dilatation was present in 34% of patients. Most clinical characteristics did not differ across abdominal aortic diameter stratified groups, but RPF mass thickness was greater in patients presenting with aortic aneurysmal dilatation compared to that in patients with an undilated aorta (49.0 mm [IQR 34.0-62.0] vs 32.5 mm [IQR 25.3-47.8]; P < 0.001). A positive linear association was found between aortic diameter on a continuous scale and RPF mass thickness (β 0.32 [95% CI 0.34-0.96]; P < 0.001). This association remained significant after adjusting for age, sex and acute-phase reactant levels (β 0.28 [95% CI 0.15-0.95]; P < 0.01). Treatment success across aortic diameter stratified groups did not differ (P = 0.98). Treatment induced RPF mass regression was not associated with an increase in aortic expansion rate (P = 0.44). Aortic dilatation was prevalent among patients. Infrarenal abdominal aortic diameter was independently associated with RPF mass thickness. Findings support the concept that at least in a subset of patients, RPF may be secondary to advanced atherosclerosis.

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.

Risk of developing an abdominal aortic aneurysm after ectatic aorta detection from initial screening

OBJECTIVE

Current abdominal aortic aneurysm (AAA) surveillance guidelines lack any follow-up recommendations after initial abdominal aortic screening diameter of less than 3.0 cm. Some reports have demonstrated patients with late AAA formation and late ruptures after initial ultrasound screening detection of patients with an aortic diameter of 2.5 to 2.9 cm (ectatic aorta). The purpose of this study was to determine ectatic aorta prevalence, AAA development, rupture risk, and risk factor profile in patients with detected ectatic aortas in a AAA screening program.

METHODS

A retrospective chart review of all patients screened for AAA from January 1, 2007, to December 31, 2016, within a regional health care system was conducted. Screening criteria were men 65 to 75 years of age that smoked a minimum of 100 cigarettes in their lifetime. An ectatic aorta was defined as a maximum aortic diameter from 2.5 to 2.9 cm. An AAA was defined as an aortic diameter of 3 cm or greater. Patients screened with ectatic aortas who had subsequent follow-up imaging of the aorta with a minimum of 1-year follow-up were analyzed for associated clinical and cardiovascular risk factors. All data were collected through December 3,/2018. A logistic regression of statistically significant variables from univariate and χ² analyses were performed to identify risks associated with the development of AAA from an initially diagnosed ectatic aorta. A Cox proportional hazard model was used to assess survival data. A P value of less than .05 was considered statistically significant.

RESULTS

From a screening pool of 19,649 patients, 3205 (16.3%) with a mean age of 72.1 ± 5.3 years were identified to have an ectatic aorta from January 1, 2007, to December 31, 2016. The average screening ectatic aortic diameter was 2.6 ± 0.1 cm. There were 672 patients (21.0%) with a mean age of 73.0 ± 5.7 years who received subsequent imaging for other clinical indications and 193 of these patients (28.7%) with ectatic aortas developed an AAA from the last follow-up scan (4.2 ± 2.5 years). The average observation length of all patients was 6.4 ± 2.9 years. No ruptures were reported, but 27.8% of deaths were of unknown cause. One patient had aortic growth to 5.5 cm or greater (0.15%). Larger initial screening diameter (P < .01), presence of chronic obstructive pulmonary disease (P < .01), and active smoking (P = .01) were associated with AAA development.

CONCLUSIONS

Patients with diagnosed ectatic aortas from screening who are active smokers or have chronic obstructive pulmonary disease are likely to develop an AAA.

Coronary Artery Disease as a Relevant Risk Factor in Screening of Abdominal Aortic Ectasia and Aneurysm

BACKGROUND

The aim of this study was to investigate the prevalence of abdominal aortic aneurysm (AAA) and abdominal aortic ectasia (AAE) in coronary artery disease (CAD) patients in a multicenter setting to obtain significant data to establish an AAA screening program in our departments.

METHODS

Between January and September 2016, 500 patients with suspected or diagnosed CAD planned for coronary angiography or coronary artery bypass graft (CABG) underwent a sonographic examination of the infrarenal abdominal aorta to diagnose AAA or AAE. We calculated the prevalence of AAA and AAE in patients diagnosed of CAD and investigated factors potentially associated with the occurrence of AAA.

RESULTS

The overall prevalence in all grades of CAD for AAE was 35.1% and for AAA 5.4%. In patients with three-vessel CAD, the prevalence of AAE was 34% and of AAA 6.8%. Significant correlation was found between the three-vessel CAD and AAA (p = 0.039). The logistic regression analysis showed significant correlation between AAA and age > 65 years (p = 0.05). The multivariate analysis of risk factors and CAD revealed significant correlations between one-vessel CAD and arterial hypertension (AH) (p = 0.004) and age > 65 years (p = 0.001) as well as between three-vessel CAD and AH (p = 0.01), peripheral artery disease (p = 0.01), and age > 65 years (p = 0.03).

CONCLUSION

Our results confirm, that in comparison to other data, the prevalence of AAA in patients with CAD is high. Thus, it is recommended to include patients with CAD, especially elderly patients with three-vessel CAD, in future AAA screening programs.

Endovascular vs Open AAA Repair: Does Size Matter?

Since the natural tendency of the aorta is to increase in diameter and tortuosity with age and since abdominal aortic aneurysms (AAAs) increase in diameter and length over time, encroaching on the renal and hypogastric orifices, early repair of AAAs (when =4.0 cm) may allow greater applicability of the endovascular option because of more favorable aortoiliac morphology. Patients who present at an older age with larger AAAs should be more likely to be anatomically excluded from endovascular AAA repair. Over a 42-month period, 317 consecutive patients referred with aortoiliac aneurysms (infrarenal AAA =4.0 cm) were evaluated by one of the authors (SGL) for endovascular vs open repair based on computed tomography (CT) and angiographic imaging. The 10 anatomic exclusion criteria were those applicable to the Zenith ® endograft (Cook, Inc), which currently is the most anatomically inclusive of the aortic endografts in commercial use in the United States. Based on their aortoiliac morphology, 212 patients were excluded from endovascular repair and 105 were included as acceptable anatomic candidates. Age, AAA size, and the reason(s) for exclusion were recorded for each patient. By use of Student's t test and logistic and linear regression analyses, the groups were compared by age, AAA size, and age + size. There was no significant difference in patient age or AAA size distribution between the group of patients excluded from endovascular repair based on aortoiliac morphology compared to those who met the inclusion criteria. Patients with small AAAs (4.0–5.4 cm) had similar age distribution as those with large (=5.5 cm) AAAs. The majority of patients (87%) were excluded based on proximal aortic neck morphology. The presence of aortoiliac morphology that precludes endovascular repair is independent of patient age or AAA size at presentation. A patient presenting with a small (4.0–5.4 cm) AAA is not more likely to be a candidate for endovascular repair than a patient with a large AAA.

The effect of recent chemotherapy in aorto-iliac aneurysm repair

The aim of the study was to investigate the effect of recent chemotherapy (Chx) on outcome of aorto-iliac aneurysm (AAA) repair. The 2005–2010 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried to identify vascular patients undergoing AAA repair within 30 days after Chx. Seventy-one patients underwent AAA repair within 30 days of receiving Chx, group A (71 ± 8.4 years, 77.5% males) and 20,024 patients underwent AAA repair without prior Chx, group B (73 ± 9 years, 79.2% males). The two groups did not significantly differ with respect to open or endovascular repair (open repair A: 32%, B: 35%, P = 0.66). However, patients in group A presented more often as emergent cases (A: 27%, B: 12%, P = 0.001). Multivariable regression analysis for emergent cases after adjustment for relevant confounders also demonstrated that patients with recent Chx present more often as emergency ( P = 0.001, odds ratio [OR]: 2.4). Thirty-day non-surgical complications were more common in group A (A: 25%, B: 16.5%, P = 0.046) while surgical complications were equivalent (A: 15.5%, B: 12.3%, P = 0.414). Risk of death was significantly higher in group A in univariate analysis (A: 13%, B: 5%, P = 0.005, OR: 2.6). Patients who receive Chx within 30 days prior to AAA repair present more frequently as emergencies leading to higher mortality. The reason for this cannot be sufficiently explained by the current database but patient selection for elective repair or the effect of Chx on the natural course of AAA may play a role.

[Infrarenal aortic ectasia in retroperitoneal fibrosis (RPF)]

We analysed the infrarenal aortic morphology by abdominal MR-examinations of 47 RPF patients compared to a control group. A significant larger aortic calibre and higher rates of infrarenal dilatation in male RPF patients were observed. The larger aortic diameter in male RPF patients may be due to periaortic inflammation with resulting aortic ectasia and supports the classification of RPF into the spectrum of chronic periaortitis.

Ultrasound surveillance of ectatic abdominal aortas

INTRODUCTION

Some studies have considered abdominal aortas of 2.6-2.9 cm diameter (ectatic aortas) at age 65 years as being abnormal and have recommended surveillance, whereas others have considered these normal and surveillance unnecessary. It is, therefore, not clear how to manage patients with an initial aortic diameter between 2.6-2.9 cm detected at screening. The aim of this study was to evaluate growth rates of ectatic aortas detected on initial ultrasound screening to determine if any developed into clinically significant abdominal aortic aneurysms (AAAs; > 5.0 cm) and clarify the appropriate surveillance intervals for these patients.

PATIENTS AND METHODS

Data were obtained from a prospective AAA screening programme which commenced in 1992. The group of patients with initial aortic diameters of 2.6-2.9 cm with a minimum of 1-year follow-up were included in this study (Group 2). This was further divided into two subgroups (Groups 3a and 3b) based on a minimum follow-up interval obtained from outcome analysis. Mean growth rate was calculated as change in aortic diameter with time. The comparison of growth rates in Groups 3a and 3b was performed using the t-test. The number and proportion of AAAs that expanded to >or= 3.0 cm and >or= 5.0 cm in diameter were also calculated.

RESULTS

Out of 999 patients with AAA >or= 2.6 cm with minimum 1-year follow-up, 358 (36%) were classified as ectatic aortas (2.6-2.9 cm) at initial ultrasound screening with the mean growth rate of 1.69 mm/year (95% CI, 1.56-1.82 mm/year) with a mean follow-up of 5.4 years. Of these 358 ectatic aortas, 314 (88%) expanded into >or= 3.0 cm, 45 (13%) expanded to >or= 5.0 cm and only 8 (2%) expanded to >or= 5.5 cm over a mean follow-up of 5.4 years (range, 1-14 years). No ectatic aortas expanded to >or= 5.0 cm within the first 4 years of surveillance. Therefore, the minimum follow-up interval was set at 4 years and this threshold was then used for further analysis. The mean growth rate in Group 3a (< 5.0 cm at last scan) was 1.33 mm/year (95% CI, 1.23-1.44 mm/year) with a mean follow-up of 7 years compared to Group 3b (>or= 5.0 cm at last scan) with the mean growth rate of 3.33 mm/year (95% CI 3.05-3.61 mm/year) and a mean follow-up of 8 years. The comparison of mean growth rates between Groups 3a and 3b is statistically significant (t-test; T = 13.00; P < 0.001).

CONCLUSIONS

One-third of patients undergoing AAA screening will have ectatic aortas (2.6-2.9 cm) and at least 13% of these will expand to a size of >or= 5.0 cm over a follow-up of 4-14 years. A threshold diameter of 2.6 cm for defining AAAs in a screening programme is recommended and ectatic aortas detected at age 65 years can be re-screened at 4 years after the initial scan. A statistically significant difference was found in the growth rates of ectatic aortas with minimum 4 years follow-up, expanding to >or= 5.0 cm compared to those less than 5.0 cm at last surveillance scan. Further studies are required to test the hypothesis of whether growth rate over the first 4 years of surveillance will identify those who are most likely to expand to a clinically significant size (> 5.0 cm).

Prevalence of abdominal aortic aneurysms in over 65-year-old men with inguinal hernias

INTRODUCTION

The aim of this study was to determine the prevalence of abdominal aortic aneurysms (AAAs) in over 65-year-old men who have inguinal hernias and discuss if pre-operative selective screening of this population is appropriate.

PATIENTS AND METHODS

A prospective study on 70 consecutive male patients with an age range of 65-88 years (mean, 74 years) who were referred to a single vascular consultant's out-patient clinic with an inguinal hernia were screened for the presence of an AAA with an ultrasound scan before hernia repair over a period of 3 years.

RESULTS

Two patients were found to have an AAA measuring 3.8 cm and 6.0 cm giving an AAA prevalence of 3% (exact 95% confidence interval = 0-10%).

CONCLUSIONS

This study does not demonstrate an increased AAA prevalence in over 65-year-old male patients with inguinal hernias, scanned pre-operatively when compared to screening programmes. Selective screening of this cohort cannot be justified on this evidence.

Cost-effectiveness of different screening strategies for abdominal aortic aneurysm

OBJECTIVE

The primary objective of this study was to develop a simulation model to assess the cost-effectiveness of different screening strategies for abdominal aortic aneurysms (AAAs) in men.

METHODS

A systematic review of the literature was conducted for different screening strategies in terms of age (60, 65, or 70 years) and risk profiles (all men or specific high-risk groups) of the screened population, and rescreening after 5 or 10 years. These data were analyzed in a Markov simulation cohort model.

RESULTS

The cost per life year gained for different screening strategies ranged from US 8,309 dollars to US 14,084 dollars and was estimated at US 10,474 dollars when 65-year-old men were screened once. Screening 60-year-old men was equally cost-effective, with the advantage of more life years gained. We demonstrated a trade-off between high prevalence of AAA and lower life expectancy, eliminating the expected benefits of screening high-risk groups such as smokers (US 10,695 dollars) or cardiovascular patients (US 10,392 dollars). Assuming general population utility resulted in a cost per quality-adjusted life year (QALY) gained of US 13,900 dollars, whereas a hypothetical 5% reduction in utility among men with a screening-detected AAA raised the cost per QALY gained to US 75,100 dollars.

CONCLUSION

This Markov model, which was based on a systematic review of the literature, supplied information on the estimated cost-effectiveness of different screening strategies. Screening men for AAA may be cost-effective in the long-term. Different screening strategies and quality-of-life effects related to screening for AAA need to be evaluated in future clinical studies.