Assessment of Subclinical Atherosclerosis in Asymptomatic People In Vivo: Measurements Suitable for Biomarker and Mendelian Randomization Studies.

BACKGROUND: One strategy to reduce the burden of cardiovascular disease is the early detection and treatment of atherosclerosis. This has led to significant interest in studies of subclinical atherosclerosis, using different phenotypes, not all of which are accurate reflections of the presence of asymptomatic atherosclerotic plaques. The aim of part 2 of this series is to provide a review of the existing literature on purported measures of subclinical disease and recommendations concerning which tests may be appropriate in the prevention of incident cardiovascular disease. METHODS: We conducted a critical review of measurements used to infer the presence of subclinical atherosclerosis in the major conduit arteries and focused on the predictive value of these tests for future cardiovascular events, independent of conventional cardiovascular risk factors, in asymptomatic people. The emphasis was on studies with >10 000 person-years of follow-up, with meta-analysis of results reporting adjusted hazard ratios (HRs) with 95% CIs. The arterial territories were limited to carotid, coronary, aorta, and lower limb arteries. RESULTS: In the carotid arteries, the presence of plaque (8 studies) was independently associated with future stroke (pooled HR, 1.89 [1.04-3.44]) and cardiac events (7 studies), with a pooled HR, 1.77 (1.19-2.62). Increased coronary artery calcium (5 studies) was associated with the risk of coronary heart disease events, pooled HR, 1.54 (1.07-2.07) and increasing severity of calcification (by Agaston score) was associated with escalation of risk (13 studies). An ankle/brachial index (ABI) of <0.9, the pooled HR for cardiovascular death from 7 studies was 2.01 (1.43-2.81). There were insufficient studies of either, thoracic or aortic calcium, aortic diameter, or femoral plaque to synthesize the data based on consistent reporting of these measures. CONCLUSIONS: The presence of carotid plaque, coronary artery calcium, or abnormal ankle pressures seems to be a valid indicator of the presence of subclinical atherosclerosis and may be considered for use in biomarker, Mendelian randomization and similar studies.

Sex-specific differences in alive hospital discharge following infrarenal abdominal aortic aneurysm repair.

BACKGROUND AND AIMS: A longer time to alive hospital discharge following infrarenal abdominal aortic aneurysm (AAA) repair is associated with reduced patient-satisfaction and increased length of stay, hospital-acquired deconditioning, infection and costs. This study investigated sex-specific differences in, and drivers of, the rate of alive hospital discharge. METHODS: Examination of UK National Vascular Registry (UK NVR), 2014-2019 and Swedish National Patient Registry (SE NPR) elective AAA patients, 2010-2018, for endovascular (EVAR) or open (OAR) aneurysm repair. Cox models assessed sex-specific difference in rate of alive hospital discharge, adjusting for co-morbidity, anatomy, standard-of-care, post-operative complications, and year, with in-hospital death as the competing risk. RESULTS: 29,751 AAA repairs (UK NVR -EVAR 12518:1532; OAR 6803:837; SE NPR - EVAR 4234:792; OAR 2638:497, men:women) were assessed. For EVAR, the unadjusted rate of alive hospital discharge was ∼25% lower for women (UK NVR HR 0.75 [0.71-0.80], p<.001; SE NPR HR 0.75 [0.69-0.81], p<.001). Following adjustment the sex-specific hazard ratio narrowed but remained significant (UK NVR: HR 0.83 [0.79-0.88], p<.001; SE NPR HR 0.83 [0.76-0.89], p<.001). For OAR, the rate of alive hospital discharge was 23-27% lower for women (UK NVR HR 0.73 [0.67-0.78], p<.001; SE NPR HR 0.77 [0.70-0.85], p<.001). Following adjustment the sex-specific hazard ratio narrowed (UK NVR HR 0.82 [0.76-0.88], p<.001; SE NPR HR 0.79 [0.72-0.88], p<.001) but remained significant. CONCLUSIONS: Women have a 25% lower rate of alive discharge after aortic surgery, despite adjustment for pre/peri- and postoperative parameters. Efforts to increase rate of alive hospital discharge for women should be sought.

Editor's Choice - A Core Outcome Set for Intact Abdominal Aortic Aneurysm Repair.

OBJECTIVE: Technology and advances in clinical care have changed the management of abdominal aortic aneurysms (AAAs) but the clinical effectiveness of continuing advances needs to be assessed. To facilitate rapid synthesis of new evidence and improve stakeholder representation, including patients, the concept of core outcome sets (COS) has been developed. COS, reflecting the needs of all stakeholders, have been established across several surgical specialties. This study aimed to develop an international core outcome set for intact AAA repair. METHODS: Following COMET methodology, potential outcomes were identified from a systematic review of published outcomes and focus groups involving patients, carers, and nurses. A 38 question Delphi consensus survey in lay language was developed (with translation to local languages); this included 35 themes identified from the findings of the systematic review and three themes from the focus groups. All three of the themes identified by the focus groups (cognitive, physical, and social functioning) can be evaluated from quality of life instruments, with overall quality of life being identified from the systematic review. The survey was completed by patients, carers or family members, vascular nurses, vascular surgeons, trainees, interventional radiologists, anaesthetists, and industry partners from six European countries. After two rounds of the survey, the top outcomes were discussed at a face to face multistakeholder consensus meeting. RESULTS: The 38 item questionnaire was amended after piloting among all stakeholder groups. After the first round of the Delphi survey (98 respondents) 15 questions were eliminated, and 11 further questions were eliminated after round 2 (90 respondents). This left two outcome questions for discussion at the consensus meeting, where the top six outcomes were unanimously endorsed: death at 30 days (or in hospital if longer), secondary AAA rupture, overall quality of life and retention of cognitive functioning after recovery, five year survival, and continued sac growth. CONCLUSION: Six core outcomes are recommended for use as a minimum framework in all future studies and registries of intact open and endovascular AAA repair. Further work to select instruments for quality of life and to define instruments for cognitive functioning is needed.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms.

OBJECTIVE: The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy. METHODS: The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence. RESULTS: A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed. CONCLUSION: The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Pathogenesis and management of abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) causes ∼170 000 deaths annually worldwide. Most guidelines recommend asymptomatic small AAAs (30 to <50 mm in women; 30 to <55 mm in men) are monitored by imaging and large asymptomatic, symptomatic, and ruptured AAAs are considered for surgical repair. Advances in AAA repair techniques have occurred, but a remaining priority is therapies to limit AAA growth and rupture. This review outlines research on AAA pathogenesis and therapies to limit AAA growth. Genome-wide association studies have identified novel drug targets, e.g. interleukin-6 blockade. Mendelian randomization analyses suggest that treatments to reduce low-density lipoprotein cholesterol such as proprotein convertase subtilisin/kexin type 9 inhibitors and smoking reduction or cessation are also treatment targets. Thirteen placebo-controlled randomized trials have tested whether a range of antibiotics, blood pressure-lowering drugs, a mast cell stabilizer, an anti-platelet drug, or fenofibrate slow AAA growth. None of these trials have shown convincing evidence of drug efficacy and have been limited by small sample sizes, limited drug adherence, poor participant retention, and over-optimistic AAA growth reduction targets. Data from some large observational cohorts suggest that blood pressure reduction, particularly by angiotensin-converting enzyme inhibitors, could limit aneurysm rupture, but this has not been evaluated in randomized trials. Some observational studies suggest metformin may limit AAA growth, and this is currently being tested in randomized trials. In conclusion, no drug therapy has been shown to convincingly limit AAA growth in randomized controlled trials. Further large prospective studies on other targets are needed.

Sex-specific differences in the standard of care for infrarenal abdominal aortic aneurysm repair, and risk of major adverse cardiovascular events and death.

BACKGROUND: This study investigated whether sex-specific differences in preoperative/perioperative standard of care (SOC) account for disparity in outcomes after elective infrarenal abdominal aortic aneurysm repair. METHODS: This was a retrospective cohort study of elective infrarenal abdominal aortic aneurysm repairs (2013-2020) using depersonalized patient-level National Vascular Registry data. SOC was defined for waiting times, preoperative assessment (multidisciplinary/anaesthetic review), cardiovascular risk prevention, and perioperative medication. The primary outcome was major cardiovascular event and/or death (MACED). RESULTS: Some 21 810 patients with an infrarenal abdominal aortic aneurysm were included, 2380 women and 19 430 men. Women less often underwent aneurysm repair within SOC waiting times (51.5 versus 59.3 per cent; P < 0.001), but were equally likely to receive preoperative assessment (72.1 versus 72.5 per cent; P = 0.742). Women were less likely to receive secondary prevention for known cardiac disease (34.9 versus 39.6 per cent; P = 0.015), but more often met overall cardiovascular risk prevention standards (52.1 versus 47.3 per cent; P < 0.001). Women were at greater risk of MACED (open: 12.0 versus 8.9 per cent, P < 0.001; endovascular: 4.9 versus 2.9 per cent, P < 0.001; risk-adjusted OR 1.33, 95 per cent c.i. 1.12 to 1.59). A significant reduction in the odds of MACED was associated with preoperative assessment (OR 0.86, 0.75 to 0.98) and SOC waiting times (OR 0.78, 0.69 to 0.87). There was insufficient evidence to confirm a significant sex-specific difference in the effect of SOC preoperative assessment (women: OR 0.69, 0.50 to 0.97; men: OR 0.89, 0.77 to 1.03; interaction P = 0.170) or SOC waiting times (women: OR 0.84, 0.62 to 1.16; men: OR 0.76, 0.67 to 0.87; interaction P = 0.570) on the risk of MACED. CONCLUSION: SOC waiting times and preoperative assessment were not met for both sexes, which was associated with an increased risk of MACED. Sex-specific differences in SOC attenuated but did not fully account for the increased risk of MACED in women.

Shared Decision Making and the Management of Intact Abdominal Aortic Aneurysm: A Scoping Review of the Literature.

OBJECTIVE: The aim of this study was to summarise the current knowledge of shared decision making (SDM) in patients facing a treatment decision about an intact abdominal aortic aneurysm (AAA), and to identify where further evidence is needed. DATA SOURCES: MEDLINE, Embase, and the Cochrane Library were searched on 18 July 2021. An updated search was run on 31 May 2022 for relevant studies published from 1 January 2000 to 31 May 2022. REVIEW METHODS: This scoping review was undertaken in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines following a pre-defined protocol, retrieving studies reporting on aspects of SDM in those with intact AAAs. Qualitative synthesis of the articles was performed, and the results grouped according to theme. RESULTS: Fifteen articles reporting on a total of 1 344 participants (age range 62-74 years) from hospital vascular surgery clinics with intact AAAs were included. Studies were observational (n = 9), non-randomised studies of an intervention (n = 3), and randomised clinical trials (n = 3). The first theme was the preferences and practice of SDM. The proportion of patients preferring SDM ranged from 58% to 95% (three studies), although objective rating of SDM practice was consistently < 50% (three studies). Clinician training improved SDM practice. The second theme was poor provision of information. Fewer than half of patients (0 - 46%) surveyed were informed about all available treatment options (three studies). Publicly available information sources were rated as poor. The third theme concerned the utility of decision making support tools (DSTs). Two randomised trials demonstrated that the provision of DSTs improves patient knowledge and agreement between patient preference and repair type received but not objective measures of SDM for patients with AAAs. CONCLUSION: SDM for patients with an intact AAA appears to be in its infancy. Most patients with an AAA want SDM, but this is not commonly applied. Most patients with an AAA do not receive adequate information for SDM, although the use of bespoke DSTs leaves patients better informed to facilitate SDM.

Towards a Core Outcome Set for Abdominal Aortic Aneurysm: Systematic Review of Outcomes Reported Following Intact and Ruptured Abdominal Aortic Aneurysm Repair.

OBJECTIVE: To encompass the needs of all stakeholders and allow effective data synthesis from trials, registries, and other studies; a core outcome set for infrarenal abdominal aortic aneurysm (AAA) repair is needed. In this first stage, the aim was to report the range, frequency, and time of pre-specified outcomes reported following AAA repair. DATA SOURCES: Medline, Embase, and CENTRAL databases 2010 - 2019 were searched using ProQuest Dialog™. REVIEW METHODS: The systematic review was reported to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (PRISMA), PROSPERO registration CRD42019130119. Outcomes were coded using Core Outcome Measures in Effectiveness Trials (COMET) taxonomy and presented separately for intact and rupture repairs, endovascular aneurysm repair (EVAR) and open repair, and time from repair (acute < 90 days vs. ≥ 1 year) (COMET Initiative 1582). RESULTS: For intact AAA and rupture repair, a total of 231 and 70 reports with 589 255 and 177 465 patients respectively were included: only 98 and 19 respectively provided ≥ 1 year outcomes. Most studies were retrospective, with 13 randomised trials of intact AAA repair and five randomised trials of ruptured AAA repair. For intact AAA, the most common pre-specified COMET taxonomy outcomes were mortality (181), vascular complications (137), and re-intervention (52). EVAR studies dominated the vascular outcomes in acute and later time periods: excluding 47 reports from device registries, reduced vascular outcomes to 83. For ruptured AAA, the three most common outcomes were mortality (64), vascular (11), and hospital stay (10). The range of outcomes reported was wide with functioning outcomes reported from most randomised trials but few retrospective studies. CONCLUSION: This review identifies the paucity of long term data and the disproportionate attention paid to vascular complications vs. patient functioning outcomes, this skew being accentuated by reporting from EVAR device registries. These data will inform focus groups, prior to a pan-European Delphi consensus, involving clinicians, patients, carers and providers, for developing core outcomes for repair of intact and ruptured AAA.

Editor's Choice - Systematic Review and Meta-Analysis of Sex Specific Differences in Adverse Events After Open and Endovascular Intact Abdominal Aortic Aneurysm Repair: Consistently Worse Outcomes for Women.

OBJECTIVE: Previously, reports have shown that women experience a higher mortality rate than men after elective open (OAR) and endovascular (EVAR) repair of abdominal aortic aneurysm (AAA). With recent improvements in overall AAA repair outcomes, this study aimed to identify whether sex specific disparity has been ameliorated by modern practice, and to define sex specific differences in peri- and post-operative complications and pre-operative status; factors which may contribute to poor outcome. METHODS: This was a systematic review, meta-analysis, and meta-regression of sex specific differences in 30 day mortality and complications conducted according to PRISMA guidance (Prospero registration CRD42020176398). Papers with ≥ 50 women, reporting sex specific outcomes, following intact primary AAA repair, from 2000 to 2020 worldwide were included; with separate analyses for EVAR and OAR. Data sources were Medline, Embase, and CENTRAL databases 2005 - 2020 searched using ProQuest Dialog. RESULTS: Twenty-six studies (371 215 men, 65 465 women) were included. Meta-analysis and meta-regression indicated that sex specific odds ratios (ORs) for 30 day mortality were unchanged from 2000 to 2020. Mortality risk was higher in women for OAR and more so for EVAR (OR [95% CI] 1.49 [1.37 - 1.61]; 1.86 [1.59 - 2.17], respectively) and this remained following multivariable risk adjustment. Transfusion, pulmonary complications, and bowel ischaemia were more common in women after OAR and EVAR (OAR: ORs 1.81 [1.60 - 2.04], 1.40 [1.28 - 1.53], 1.54 [1.36 - 1.75]; EVAR: ORs 2.18 [2.08 - 2.29] 1.44 [1.17 - 1.77], 1.99 [1.51 - 2.62], respectively). Arterial injury, limb ischaemia, renal and cardiac complications were more common in women after EVAR (ORs 3.02 [1.62 - 5.65], 2.13 [1.48 - 3.06], 1.46 [1.22 - 1.72] and 1.19 [1.03 - 1.37], respectively); the latter was associated with greater mortality risk on meta-regression. CONCLUSION: Increased mortality risk for women following AAA repair remains. Women had a higher incidence of transfusion, pulmonary and bowel complications after EVAR and OAR. Higher mortality risk ratios for EVAR may result from cardiac complications, additional arterial injury, and embolisation, leading to renal and limb ischaemia. These findings indicate possible causes for observed outcome disparities and targets for quality improvement.

Morphology and Hemodynamics in Isolated Common Iliac Artery Aneurysms Impacts Proximal Aortic Remodeling.

Objective- Isolated common iliac artery aneurysms (CIAA) are rare. Their prognosis and influence on aortoiliac blood flow and remodeling are unclear. We evaluated the hypotheses that morphology at and distal to the aortic bifurcation, together with the associated hemodynamic changes, influence both the natural history of CIAA and proximal aortic remodeling. Approach and Results- Twenty-five isolated CIAAs (15 intact, 10 ruptured), in 23 patients were reconstructed and analyzed with computational fluid dynamics: all showed abnormal flow. Then we studied a series of 24 hypothetical aortoiliac geometries in silico with varying abdominal aortic deflection and aortic bifurcation angles: key findings were assessed in an independent validation cohort of 162 patients. Wall shear stress in isolated unilateral CIAAs was lower than the contralateral common iliac artery, 0.38±0.33 Pa versus 0.61±0.24 Pa, inversely associated with CIAA diameter ( P<0.001) and morphology (high shear stress in variants distal to a sharp kink). Rupture usually occurred in regions of elevated low and oscillatory shear with a wide aortic bifurcation angle. Abdominal aortas deflected towards the CIAA for most unilateral isolated CIAAs (14/21). In silico, wider bifurcation angles created high focal regions of low and oscillatory shear in the common iliac artery. The associations of unilateral CIAA with aortic deflection and common iliac artery diameter with bifurcation angle were confirmed in the validation cohort. Conclusions- Decreasing wall shear stress is strongly associated with CIAA progression (larger aneurysms and rupture), whereas abnormal blood flow in the CIAA seems to promote proximal aortic remodeling, with adaptive lateral deflection of the abdominal aorta towards the aneurysmal side.

Analysis of the Differences Between the ESVS 2019 and NICE 2020 Guidelines for Abdominal Aortic Aneurysm.

OBJECTIVE: The aim was to understand why two recently published guidelines for the diagnosis and management of patients with abdominal aortic aneurysm, the National Institute for Health and Care Excellence (NICE) 2020 guidelines and the European Society for Vascular Surgery (ESVS) 2019 guidelines, have discordant recommendations in several important areas. METHODS: A review of the approach, methodology, and evidence used by the two guideline committees was carried out to understand potential reasons for their differing recommendations in their two final published guidelines. RESULTS: NICE guidelines use a multidisciplinary committee to address a limited number of prospectively identified questions, using rigorous methods heavily reliant on evidence from randomised controlled trials (RCTs) supported by in house economic modelling, with the purpose of providing the best, cost-effective health care in the UK in 46 main recommendations. The ESVS guidelines use an expert committee to encourage clinical effectiveness across a range of European health economies. ESVS guideline topics, but not questions, are prospectively identified, assessment of evidence was less rigorous, and 125 recommendations were made. More up to date evidence searches by the ESVS committee partially underscore the differences in recommendations for screening women. The NICE committee did not consider sex specific analysis or evidence for thresholds for intervention but relied on sex specific modelling to support their advice to use endovascular repair (EVAR) for ruptures in women. Their recommendation to use open repair for ruptured abdominal aortic aneurysms (AAAs) in men aged < 71 years was based on in house economic modelling. NICE recommends an open first strategy for non-ruptured AAA mainly based on earlier RCTs and UK specific economic modelling, while the ESVS guidelines recommend an EVAR first strategy after consideration of modern, but lower quality, evidence from observational studies. Similar reasons explain differences in the recommended treatments of juxtarenal aneurysms. CONCLUSION: Differences between the NICE and ESVS guidelines can be explained, at least in part, by their differing perspectives, methodologies, and quality assurance. Future ESVS guidelines may benefit from more multidisciplinary input and prospectively identified questions.

Morphology and Computational Fluid Dynamics Support a Novel Classification of Common Iliac Aneurysms.

OBJECTIVE: Isolated common iliac artery aneurysms (CIAAs) are uncommon, and evidence concerning their development, progression, and management is weak. The objective was to describe the morphology and haemodynamics of isolated CIAAs in a retrospective study. METHODS: Initially, a series of 25 isolated CIAAs (15 intact, 10 ruptured) in 23 patients were gathered from multiple centres, reconstructed from computed tomography, and then morphologically classified and analysed with computational fluid dynamics. The morphological classification was applied in a separate, consecutive cohort of 162 patients assessed for elective aorto-iliac intervention, in which 55 patients had intact CIAAs. RESULTS: In the isolated CIAA cohort, three distinct morphologies were identified: complex (involving a bifurcation); fusiform; and kinked (distal to a sharp bend in the CIA), with mean diameters of 90.3, 48.3, and 31.7 mm, and mean time averaged wall shear stresses of 0.16, 0.31, and 0.71 Pa, respectively (both analysis of variance p values < .001). Kinked cases vs. fusiform cases had less thrombus and favourable haemodynamics similar to the non-aneurysmal contralateral common iliac artery (CIA). Ruptured isolated CIAAs were large (mean diameter 87.5 mm, range 55.5-138.0 mm) and predominantly complex. The mean CIA length for aneurysmal arteries was greatest in kinked cases followed by complex and fusiform (100.8 mm, 91.1 mm, and 80.6 mm, respectively). The morphological classification was readily applicable to a separate elective patient cohort. CONCLUSION: A new morphological categorisation of CIAAs is proposed. Potentially this is associated with both haemodynamics and clinical course. Further research is required to determine whether the kinked CIAA is protected haemodynamically from aneurysm progression and to establish the wider applicability of the categorisation presented.

Meta-Analysis and Meta-Regression Analysis of Outcomes of Endovascular and Open Repair for Ruptured Abdominal Aortic Aneurysm.

OBJECTIVE: The aim was to assess peri-operative mortality of endovascular aneurysm repair (EVAR) vs. open repair for ruptured abdominal aortic aneurysm (AAA) and to investigate whether outcomes have improved over the years and whether there is an association between institutional caseload and peri-operative mortality. METHODS: Electronic information sources (MEDLINE, EMBASE, CINAHL and CENTRAL) were searched up to August 2019. A systematic review was carried out according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using a registered protocol (CRD42018106084). Studies were selected that reported peri-operative mortality of EVAR for ruptured AAA. A proportion meta-analysis was conducted, and summary estimates of odds ratios (ORs) and 95% confidence intervals (CIs) for EVAR vs. open surgical repair were obtained using random effects models. Mixed effects regression models were developed to investigate outcome changes over time and with institutional caseload. RESULTS: One hundred and thirty-six studies were included in quantitative synthesis reporting a total of 267 259 patients (EVAR 58 273; open surgery 208 986). The pooled peri-operative mortality of EVAR and open surgical repair was 0.245 (95% CI 0.234-0.257) and 0.378 (95% CI 0.364-0.392), respectively. EVAR was associated with reduced peri-operative mortality (OR 0.54, 95% CI 0.51-0.57, p < .001). Meta-regression analysis found decreasing peri-operative mortality over the years following EVAR (p < .001) and open repair (p < .001), and a decreasing OR of peri-operative mortality in favour of EVAR (p = .053). Meta-regression found a significant positive association between peri-operative mortality and institutional case load for open repair (p = .004). CONCLUSION: If EVAR can be done, it is a better treatment for ruptured AAA in view of the reduced peri-operative mortality compared with open surgery. The outcomes of both EVAR and open surgical repair have improved over the years, and the difference in peri-operative mortality in favour of EVAR has become more pronounced. There is a significant association between peri-operative mortality and institutional case load for open repair of ruptured AAA.

Biomechanical Assessment Predicts Aneurysm Related Events in Patients with Abdominal Aortic Aneurysm.

OBJECTIVE: To test whether aneurysm biomechanical ratio (ABR; a dimensionless ratio of wall stress and wall strength) can predict aneurysm related events. METHODS: In a prospective multicentre clinical study of 295 patients with an abdominal aortic aneurysm (AAA; diameter ≥ 40 mm), three dimensional reconstruction and computational biomechanical analyses were used to compute ABR at baseline. Participants were followed for at least two years and the primary end point was the composite of aneurysm rupture or repair. RESULTS: The majority were male (87%), current or former smokers (86%), most (72%) had hypertension (mean ± standard deviation [SD] systolic blood pressure 140 ± 22 mmHg), and mean ± SD baseline diameter was 49.0 ± 6.9 mm. Mean ± SD ABR was 0.49 ± 0.27. Participants were followed up for a mean ± SD of 848 ± 379 days and rupture (n = 13) or repair (n = 102) occurred in 115 (39%) cases. The number of repairs increased across tertiles of ABR: low (n = 24), medium (n = 34), and high ABR (n = 44) (p = .010). Rupture or repair occurred more frequently in those with higher ABR (log rank p = .009) and ABR was independently predictive of this outcome after adjusting for diameter and other clinical risk factors, including sex and smoking (hazard ratio 1.41; 95% confidence interval 1.09-1.83 [p = .010]). CONCLUSION: It has been shown that biomechanical ABR is a strong independent predictor of AAA rupture or repair in a model incorporating known risk factors, including diameter. Determining ABR at baseline could help guide the management of patients with AAA.

Surgery for small asymptomatic abdominal aortic aneurysms.

BACKGROUND: An abdominal aortic aneurysm (AAA) is an abnormal ballooning of the major abdominal artery. Some AAAs present as emergencies and require surgery; others remain asymptomatic. Treatment of asymptomatic AAAs depends on many factors, but the size of the aneurysm is important, as risk of rupture increases with aneurysm size. Large asymptomatic AAAs (greater than 5.5 cm in diameter) are usually repaired surgically; very small AAAs (less than 4.0 cm diameter) are monitored with ultrasonography. Debate continues over the roles of early repair versus surveillance with repair on subsequent enlargement in people with asymptomatic AAAs of 4.0 cm to 5.5 cm diameter. This is the fourth update of the review first published in 1999. OBJECTIVES: To compare mortality and costs, as well as quality of life and aneurysm rupture as secondary outcomes, following early surgical repair versus routine ultrasound surveillance in people with asymptomatic AAAs between 4.0 cm and 5.5 cm in diameter. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, two other databases, and two trials registers to 10 July 2019. We handsearched conference proceedings and checked reference lists of relevant studies. SELECTION CRITERIA: We included randomised controlled trials where people with asymptomatic AAAs of 4.0 cm to 5.5 cm were randomly allocated to early repair or imaging-based surveillance at least every six months. Outcomes had to include mortality or survival. DATA COLLECTION AND ANALYSIS: Three review authors independently extracted data, which were cross-checked by other team members. Outcomes were mortality, costs, quality of life, and aneurysm rupture. For mortality, we estimated risk ratios (RR) (endovascular aneurysm repair only), hazard ratios (HR) (open repair only), and 95% confidence intervals (CI) based on Mantel-Haenszel Chi2 statistics at one and six years (open repair only) following randomisation. MAIN RESULTS: We found no new studies for this update. Four trials with 3314 participants fulfilled the inclusion criteria. Two trials compared early open repair with surveillance and two trials compared early endovascular repair (EVAR) with surveillance. We used GRADE to access the certainty of the evidence for mortality and cost, which ranged from high to low. We downgraded the certainty in the evidence from high to moderate and low due to risk of bias concerns and imprecision (some outcomes were only reported by one study). All four trials showed an early survival benefit in the surveillance group (due to 30-day operative mortality with repair) but no evidence of differences in long-term survival. One study compared early open repair with surveillance with an adjusted HR of 0.88 (95% CI 0.75 to 1.02, mean follow-up 10 years; HR 1.21, 95% CI 0.95 to 1.54, mean follow-up 4.9 years). Pooled analysis of participant-level data from the two trials comparing early open repair with surveillance (maximum follow-up seven to eight years) showed no evidence of a difference in survival (propensity score-adjusted HR 0.99, 95% CI 0.83 to 1.18; 2226 participants; high-certainty evidence). This lack of treatment effect did not vary to three years by AAA diameter (P = 0.39), participant age (P = 0.61), or for women (HR 0.84, 95% CI 0.62 to 1.11). Two studies compared EVAR with surveillance and there was no evidence of a survival benefit for early EVAR at 12 months (RR 1.92, 95% CI 0.73 to 5.06; 846 participants; low-certainty evidence). Two trials reported costs. The mean UK health service costs per participant over the first 18 months after randomisation were higher in the open repair surgery than the surveillance group (GBP 4978 in the repair group versus GBP 3914 in the surveillance group; mean difference (MD) GBP 1064, 95% CI 796 to 1332; 1090 participants; moderate-certainty evidence). There was a similar difference after 12 years. The mean USA hospital costs for participants at six months after randomisation were higher in the EVAR group than in the surveillance group (USD 33,471 with repair versus USD 5520 with surveillance; MD USD 27,951, 95% CI 25,156 to 30,746; 614 participants; low-certainty evidence). After four years, there was no evidence of a difference in total medical costs between groups (USD 48,669 with repair versus USD 46,112 with surveillance; MD USD 2557, 95% CI -8043 to 13,156; 614 participants; low-certainty evidence). All studies reported quality of life but used different assessment measurements and results were conflicting. All four studies reported aneurysm rupture. There were very few ruptures reported in the trials of EVAR versus surveillance up to three years. In the trials of open surgery versus surveillance, there were ruptures to at least six years and there were more ruptures in the surveillance group, but most of these ruptures occurred in aneurysms that had exceeded the threshold for surgical repair. AUTHORS' CONCLUSIONS: There was no evidence of an advantage to early repair for small AAA (4.0 cm to 5.5 cm), regardless of whether open repair or EVAR is used and, at least for open repair, regardless of patient age and AAA diameter. Thus, neither early open nor early EVAR of small AAAs is supported by currently available evidence. Long-term data from the two trials investigating EVAR are not available, so, we can only draw firm conclusions regarding outcomes after the first few years for open repair. Research regarding the risks related to and management of small AAAs in ethnic minorities and women is urgently needed, as data regarding these populations are lacking.

Analysis of clinical benefit, harms, and cost-effectiveness of screening women for abdominal aortic aneurysm.

BACKGROUND: A third of deaths in the UK from ruptured abdominal aortic aneurysm (AAA) are in women. In men, national screening programmes reduce deaths from AAA and are cost-effective. The benefits, harms, and cost-effectiveness in offering a similar programme to women have not been formally assessed, and this was the aim of this study. METHODS: We developed a decision model to assess predefined outcomes of death caused by AAA, life years, quality-adjusted life years, costs, and the incremental cost-effectiveness ratio for a population of women invited to AAA screening versus a population who were not invited to screening. A discrete event simulation model was set up for AAA screening, surveillance, and intervention. Relevant women-specific parameters were obtained from sources including systematic literature reviews, national registry or administrative databases, major AAA surgery trials, and UK National Health Service reference costs. FINDINGS: AAA screening for women, as currently offered to UK men (at age 65 years, with an AAA diagnosis at an aortic diameter of ≥3·0 cm, and elective repair considered at ≥5·5cm) gave, over 30 years, an estimated incremental cost-effectiveness ratio of £30 000 (95% CI 12 000-87 000) per quality-adjusted life year gained, with 3900 invitations to screening required to prevent one AAA-related death and an overdiagnosis rate of 33%. A modified option for women (screening at age 70 years, diagnosis at 2·5 cm and repair at 5·0 cm) was estimated to have an incremental cost-effectiveness ratio of £23 000 (9500-71 000) per quality-adjusted life year and 1800 invitations to screening required to prevent one AAA-death, but an overdiagnosis rate of 55%. There was considerable uncertainty in the cost-effectiveness ratio, largely driven by uncertainty about AAA prevalence, the distribution of aortic sizes for women at different ages, and the effect of screening on quality of life. INTERPRETATION: By UK standards, an AAA screening programme for women, designed to be similar to that used to screen men, is unlikely to be cost-effective. Further research on the aortic diameter distribution in women and potential quality of life decrements associated with screening are needed to assess the full benefits and harms of modified options. FUNDING: UK National Institute for Health Research Health Technology Assessment programme.