Canadian Task Force on Preventive Health Care. Recommendations on screening for abdominal aortic aneurysm in primary care

Machine learning-based prediction of abdominal aortic aneurysms for individualized patient care

OBJECTIVE

The United States Preventative Services Task Force guidelines for screening for abdominal aortic aneurysms (AAA) are broad and exclude many at risk groups. We analyzed a large AAA screening database to examine the utility of a novel machine learning (ML) model for predicting individual risk of AAA.

METHODS

We created a ML model to predict the presence of AAAs (>3 cm) from the database of a national nonprofit screening organization (AAAneurysm Outreach). Participants self-reported demographics and comorbidities. The model is a two-layered feed-forward shallow network. The ML model then generated AAA probability based on patient characteristics. We evaluated graphs to determine significant factors, and then compared those graphs with a traditional logistic regression model.

RESULTS

We analyzed a cohort of 10,033 patients with an AAA prevalence of 2.74%. Consistent with logistic regression analysis, the ML model identified the following predictors of AAA: Caucasian race, male gender, advancing age, and recent or past smoker with recent smoker having a more profound affect (P < .05). Interestingly, the ML model showed body mass index (BMI) was associated with likelihood of AAAs, especially for younger females. The ML model also identified a higher than predicted risk of AAA in several groups, including female nonsmokers with cardiac disease, female diabetics, those with a family history of AAA, and those with hypertension or hyperlipidemia at older ages. An elevated BMI conveyed a higher than expected risk in male smokers and all females. The ML model also identified a complex relationship of both diabetes mellitus and hyperlipidemia with gender. Family history of AAA was a more important risk factor in the ML model for both men and women too.

CONCLUSIONS

We successfully developed an ML model based on an AAA screening database that unveils a complex relationship between AAA prevalence and many risk factors, including BMI. The model also highlights the need to expand AAA screening efforts in women. Using ML models in the clinical setting has the potential to deliver precise, individualized screening recommendations.

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.

Ultrasound screening for abdominal aortic aneurysm in primary care

INTRODUCTION

Abdominal aortic aneurysm (AAA) constitutes a pathology with high mortality. There is currently no screening program implemented in primary care in Spain.

OBJECTIVES

To evaluate the usefulness of ultrasound in the detection of AAA in the at-risk population in primary care. Secondarily, to identify subjects whose vascular risk (VR) should be reclassified and to determine whether AAA is associated with the presence of carotid plaque and other risk factors.

MATERIAL AND METHODS

Cross-sectional, descriptive, multicenter, national, descriptive study in primary care.

SUBJECTS

A consecutive selection of hypertensive males aged between 65 and 75 who are either smokers or former smokers, or individuals over the age of 50 of both sexes with a family history of AAA.

MEASUREMENTS

Diameter of abdominal aorta and iliac arteries; detection of abdominal aortic and carotid atherosclerotic plaque. VR was calculated at the beginning and after testing (SCORE).

RESULTS

One hundred and fifty patients were analyzed (age: 68.3±5 years; 89.3% male). Baseline RV was high/very high in 55.3%. AAA was detected in 12 patients (8%; 95% CI: 4-12); aortic ectasia in 13 (8.7%); abdominal aortic plaque in 44% and carotid plaque in 62% of the participants. VR was reclassified in 50% of subjects. The detection of AAA or ectasia was associated with the presence of carotid plaque, current smoking and lipoprotein(a), p<0.01.

CONCLUSIONS

The prevalence of AAA in patients with VR is high. Ultrasound in primary care allows detection of AAA and subclinical atherosclerosis and consequently reclassification of the VR, demonstrating its utility in screening for AAA in the at-risk population.

One-time screening for abdominal aortic aneurysm in Ontario, Canada: a model-based cost-utility analysis

BACKGROUND

Screening programs for abdominal aortic aneurysm (AAA) are not available in Canada. We sought to determine the effectiveness and costutility of AAA screening in Ontario.

METHODS

We compared one-time ultrasonography-based AAA screening for people aged 65 years to no screening using a fully probabilistic Markov model with a lifetime horizon. We estimated life-years, quality-adjusted life-years (QALYs), AAA-related deaths, number needed to screen to prevent 1 AAA-related death and costs (in Canadian dollars) from the perspective of the Ontario Ministry of Health. We retrieved model inputs from literature, Statistics Canada, and the Ontario Case Costing Initiative.

RESULTS

Screening reduced AAA-related deaths by 84.9% among males and 81.0% among females. Compared with no screening, screening resulted in 0.04 (18.96 v. 18.92) additional life-years and 0.04 (14.95 v. 14.91) additional QALYs at an incremental cost of $80 per person among males. Among females, screening resulted in 0.02 (21.25 v. 21.23) additional life-years and 0.01 (16.20 v. 16.19) additional QALYs at an incremental cost of $11 per person. At a willingness-to-pay of $50 000 per year, screening was cost-effective in 84% (males) and 90% (females) of model iterations. Screening was increasingly cost-effective with higher AAA prevalence.

INTERPRETATION

Screening for AAA among people aged 65 years in Ontario was associated with fewer AAA-related deaths and favourable cost-effectiveness. To maximize QALY gains per dollar spent and AAA-related deaths prevented, AAA screening programs should be designed to ensure that populations with high prevalence of AAA participate.

Trends in Incidence of Abdominal Aortic Aneurysm Rupture, Repair, and Mortality in Nova Scotia

BACKGROUND

The purpose of this study was to examine sex-based trends in incidence of elective abdominal aortic aneurysm (AAA), ruptured AAA, ruptured AAA repair, and AAA-related mortality.

METHODS

A retrospective analysis of patients presenting with AAA from 2005 to 2015 was conducted. Rates of elective AAA repair, ruptured AAA, ruptured AAA repair, and mortality were obtained from linking provincial administrative data using medical services insurance billing number. The age-adjusted incidence of elective AAA repair, overall rate of ruptured AAA, ruptured AAA repair, and AAA-related mortality was calculated for each sex based on Canadian census estimates, adjusted to the Canadian standard population. Weighted linear regression was performed to analyze trends in incidence over time.

RESULTS

One thousand nine hundred eighty-six elective AAA repairs were identified, of which 1,098 were repaired open and 898 underwent endovascular abdominal aneurysm repair (EVAR). Five hundred and seventy ruptured AAAs were identified, of which 295 (52%) were repaired: 259 open and 36 EVAR. The proportion of ruptured AAA that was repaired did not change over time (P = 0.54). The proportion repairs performed using EVAR increased significantly in both elective (P < 0.001) and rupture repairs (P < 0.001). During the study period, 662 patients died of AAA-associated mortality. The average incidence of elective AAA repair in men was 29.3 (95% confidence interval (CI): 27.8 to 30.8) per 100,000 and decreased over time (P = 0.04), whereas the average incidence in women was 9.2 [8.3 to 10.0] and stable (P = 0.07). The incidence of open elective AAA repair was 10.5 [9.9-11.1] with a decreasing trend over time (P < 0.001) and EVAR was 9.0 (8.5-9.6) with an increasing trend over time (P < 0.001). A decreasing trend of overall ruptured AAA (5.4 [5.0-5.9], P < 0.001), ruptured AAA repair (2.9 [2.5-3.2], P = 0.02), and of AAA-related mortality (6.2 [5.8-6.8], P < 0.001) was found, with consistent trends in both sexes. The incidence of open ruptured AAA repair decreased over time (P = 0.001) whereas the incidence of ruptured EVAR remained stable (P = 0.23).

CONCLUSIONS

The incidence of elective AAA repair is decreasing in males but not females, whereas the incidence of rupture has decreased in both sexes. This has translated into reduced incidence of AAA-related mortality. Increased adoption of EVAR for ruptured AAA should continue these trends.

Mouse Abdominal Aortic Aneurysm Model Induced by Periarterial Incubation of Papain

For decades, numerous experimental animal models have been developed to examine the pathophysiologic mechanisms and potential treatments for abdominal aortic aneurysms (AAAs) in diverse species with varying chemical or surgical approaches. This study aimed to create an AAA mouse model by the periarterial incubation with papain, which can mimic human AAA with advantages such as simplicity, convenience, and high efficiency. Eighty C57BL/6J male mice were randomly assigned to 1 of the 4 groups: papain (1.0 or 2.0 mg), porcine pancreatic elastase, and phosphate-buffered solution. The aortic segment was wrapped for 20 minutes, and the diameter was measured using ultrasound preoperatively and postoperative days 7 and 14. Then, the mice were killed for histomorphometric and immunohistochemical analyses. According to ultrasound measurements and histomorphometric analyses, on postoperative day 7, 65% of mice in the 1.0-mg papain group and 60% of mice in the 2.0-mg papain group developed AAA. In both papain groups, 100% of mice developed AAA, and 65% of mice in the porcine pancreatic elastase group developed AAA on postoperative day 14. Furthermore, hematoxylin/eosin, elastin van Gieson, and Masson staining of tissues from the papain group revealed thickened media and intimal hyperplasia, collagen sediments, and elastin destruction, indicating that AAA histochemical alteration was similar to that of humans. In addition, the immunohistochemical analysis was conducted to detect infiltrated inflammatory cells, such as macrophages and leukocytes, in the aortic wall and hyperplasic adventitia. The expression of matrix metalloproteinase 2 and 9 was significantly upregulated in papain and human AAA tissues. Periarterial incubation with 1.0 mg of papain for 20 minutes can successfully create an experimental AAA model in mice for 14 days, which can be used to explore the mechanism and treatment of human AAA.

Sex and Gender Bias as a Mechanistic Determinant of Cardiovascular Disease Outcomes

Defined as a prejudice either for or against something, biases at the provider, patient, and societal level all contribute to differences in cardiovascular disease recognition and treatment, resulting in outcome disparities between sexes and genders. Provider bias in the under-recognition of female-predominant cardiovascular disease and risks might result in underscreened and undertreated patients. Furthermore, therapies for female-predominant phenotypes including nonobstructive coronary artery disease and heart failure with preserved ejection fraction are less well researched, contributing to undertreated female patients. Conversely, women are less likely to seek urgent medical attention, potentially related to societal bias to put others first, which contributes to diagnostic delays. Furthermore, women are less likely to have discussions around risk factors for coronary artery disease compared with men, partially because they are less likely to consider themselves at risk for heart disease. Provider bias in interpreting a greater number of presenting symptoms, some of which have been labelled as "atypical," can lead to mislabelling presentations as noncardiovascular. Furthermore, providers might avoid discussions around certain therapies including thrombolysis for stroke, and cardiac resynchronization therapy in heart failure, because it is incorrectly assumed that women are not interested in pursuing options deemed more invasive. To mitigate bias, organizations should aim to increase the visibility and involvement of women in research, health promotion, and clinical and leadership endeavours. More research needs to be done to identify effective interventions to mitigate sex and gender bias and the resultant cardiovascular outcome discrepancies.

Abdominal aortic aneurysm screening in an academic family practice: Short-term impact of guideline changes

OBJECTIVE

To investigate abdominal aortic aneurysm (AAA) screening rates in the 6 months before and after the introduction of updated Canadian Task Force on Preventive Health Care (CTFPHC) guidelines to determine effects on practice patterns, as well as to determine whether certain patient characteristics impact AAA screening rates.

DESIGN

Retrospective chart review.

SETTING

Academic family health centre in London, Ont.

PARTICIPANTS

Male patients between the ages of 65 and 80.

MAIN OUTCOME MEASURES

Screening rates for AAA before and after the guideline update were compared using the normal approximation of the binomial distribution. Analysis of demographic characteristic effects on screening rates was completed with the Fisher exact test. Number of visits to the clinic with a primary care provider within the study period and imaging type were collected.

RESULTS

Of the 266 patients included in the study, 160 patients were eligible for screening at the start of the study period, 6 months before publication of the CTFPHC AAA guideline. Individuals eligible for screening visited the clinic an average (SD) of 2.44 (1.82) times in the 6 months before and 2.66 (1.99) times in the 6 months after. Overall, 69 individuals had AAA screening completed and 9 had a discussion of AAA screening without any imaging, for a total uptake rate of 88.5% for those who had screening recommended. The overall imaging rate was 48.9%. There was no statistically significant difference in screening rates between the time periods (P=.337) among those eligible for screening. For demographic characteristics for risk stratification, 7 individuals had a documented family history, of whom 5 had imaging of their abdominal aorta performed, plus 1 additional individual who had screening recommended but not completed. This was not statistically significant relative to the total population (P=.0598). Positive smoking status (active or ex-smoker) was more common, with 135 individuals having a relevant smoking history. Approximately half of these current and former smokers (68 individuals [50.4%]) had any sort of abdominal aortic imaging performed or recommended, which was not statistically significantly different compared with non-smokers (62 of 126 imaging performed or recommended, 49.2%; P=.9016).

CONCLUSION

Screening practices did not change appreciably with the introduction of the CTFPHC AAA screening guidelines. Further research is needed to improve AAA screening rates. It is worth exploring electronic medical record-based reminders, nursing staff involvement in screening, screening programs via public health, and point-of-care ultrasound screening in a primary care setting.

Point-of-care ultrasound: An emerging clinical tool to enhance physical assessment

ABSTRACT

Point-of-care ultrasound (PoCUS) is a cost-effective diagnostic technology that, with training, is accessible, portable, and a convenient diagnostic modality to complement physical assessments. PoCUS is beneficial in that it can reduce the number of imaging tests required, while also mitigating barriers to healthcare for rural and remote communities.

Screening for abdominal aortic aneurysms in Canada: 2020 review and position statement of the Canadian Society for Vascular Surgery

Abdominal aortic aneurysms (AAAs) remain a major risk to patients, despite level 1 evidence for screening to prevent rupture events and decrease mortality. In 2007, the Canadian Society for Vascular Surgery (CSVS) published a review and position statement for AAA screening in Canada. Since that publication, there have been a number of updates in the published literature affecting screening recommendations. In this paper, we present a review of some of the controversies in the AAA screening literature to help elucidate differences in the various published screening guidelines. This article represents a review of the data and updated recommendations for AAA screening in the Canadian population on behalf of the CSVS.

Les anévrismes de l’aorte abdominale (AAA) continuent de poser un risque majeur pour les patients, malgré des données probantes de niveau 1 à l’appui du dépistage pour prévenir les ruptures et réduire la mortalité. En 2007, la Société canadienne de chirurgie vasculaire (SCCV) a publié une revue et un énoncé de position sur le dépistage de l’AAA au Canada. Depuis lors, plusieurs mises à jour ont paru dans la littérature et elles ont un impact sur les recommandations relatives au dépistage. Dans le présent article, nous présentons une synthèse de quelques controverses soulevées dans la littérature sur le dépistage de l’AAA afin d’expliquer les différences entre les diverses lignes directrices publiées à ce sujet. Cet article propose au nom de la SCCV une revue des données probantes et des recommandations à jour sur le dépistage de l’AAA dans la population canadienne.

Appraisal of transthoracic echocardiography for opportunistic screening of abdominal aortic aneurysm

ABSTRACT

Abdominal aortic aneurysm is a life threatening disease. Most of the patients diagnosed incidentally because of the asymptomatic nature of this disease. This study aimed to determine the frequency of abdominal aortic aneurysm and evaluate the value of opportunistic screening during transthoracic echocardiography.A total of 5138 patients referred for echocardiographic evaluation for any reason were screened for abdominal aortic aneurysm between November 2014 to July 2019. The aneurysm was defined as an abdominal aorta with a diameter greater than 30 mm, or segmental dilatation of more than 50% of its size in non-dilated parts.The overall frequency of abdominal aortic aneurysm was 2.2% (n = 109) in the study population. Male sex (P < .001), older age (P < .001), presence of diastolic dysfunction (P = .036), hypertension (P < .001), coronary artery disease (P < .001), and hyperlipidemia (P < .001) were associated with abdominal aortic aneurysm. Patients with aneurysm had significantly increased diameters of the aortic trunk (P < .001) and ascending aorta (P < .001), significantly thicker interventricular septum (P < .001) and posterior wall (P < .001), significantly increased end-diastolic diameter (P < .001) and enlarged left atrium (P < .001), and significantly decreased ejection fraction (P < .001). The mostly met criteria for screening abdominal aortic aneurysm in international guidelines was the age of the patients.Based on the results of this study, screening patients over 60 years of age who undergo a transthoracic echocardiography for any reason would be beneficial to detect an asymptomatic abdominal aortic aneurysm in Turkish population.

Global Burden of Aortic Aneurysm and Attributable Risk Factors from 1990 to 2017

Background

To date, our understanding of the global aortic aneurysm (AA) burden distribution is very limited.

Objective

To assess a full view of global AA burden distribution and attributable risk factors from 1990 to 2017.

Methods

We extracted data of AA deaths, disability-adjusted life years (DALYs), and their corresponding age-standardized rates (ASRs), in general and by age/sex from the 2017 Global Burden of Disease (GBD) study. The current AA burden distribution in 2017 and its changing trend from 1990 to 2017 were separately showed. The spatial divergence was discussed from four levels: global, five social-demographic index regions, 21 GBD regions, and 195 countries and territories. We also estimated the risk factors attributable to AA related deaths.

Results

Globally, the AA deaths were 167,249 with an age-standardized death rate (ASDR) of 2.19/100,000 persons in 2017, among which the elderly and the males accounted for the majority. Although reductions in ASRs were observed in developed areas, AA remained an important health issue in those relatively underdeveloped areas and might be much more important in the near future. AA may increasingly affect the elderly and the female population. Similar patterns of AA DALYs burden were noted during the study period. AA burden attributable to high blood pressure and smoking decreased globally and there were many heterogeneities in their distribution.

Discussion

AA maintained an incremental public health issue worldwide. The change pattern of AA burden was heterogeneous across locations, ages, and sexes and it is paramount to improve resource allocation for more effective and targeted prevention strategies. Also, prevention of tobacco consumption and blood pressure control should be emphasized.

Screening Older Adult Men for Abdominal Aortic Aneurysm: A Scoping Review

Abdominal aortic aneurysm (AAA) is a potentially fatal condition predominantly affecting older adult men (60 years or over). Based on evidence, preventative health-care guidelines recommend screening older males for AAA using ultrasound. In attempts to reduce AAA mortality among men, screening has been utilized for early detection in some Western countries including the UK and Sweden. The current scoping review includes 19 empirical studies focusing on AAA screening in men. The findings from these studies highlight benefits and potential harms of male AAA screening. The benefits of AAA screening for men include decreased incidence of AAA rupture, decreased AAA mortality, increased effectiveness of elective AAA repair surgery, and cost-effectiveness. The potential harms of AAA screening included lack of AAA mortality reduction, negative impacts on quality of life, and inconsistent screening eligibility criteria being applied by primary care practitioners. The current scoping review findings are discussed to suggest changes to AAA screening guidelines and improve policy and practice.

GRADE Concept Paper 1: Validating the "F.A.C.E" instrument using stakeholder perceptions of feasibility, acceptability, cost, and equity in guideline implement

BACKGROUND AND OBJECTIVE

To present a structured approach for assessing stakeholder perceptions and implementing the approach in guideline development.

METHODS

This work was carried out by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Equity and Stakeholder Engagement Project Groups through brainstorming and iterative frameworks, stakeholder engagement, pilot testing, refinement of ideas, using input from workshops, and discussions at GRADE Working Group meetings to produce this document, which constitutes a GRADE conceptual article on implementation.

RESULTS

We introduce the FACE implementation criteria, feasibility, acceptability, cost, and equity; priority; and "intent to implement" criterion. We outline the implementation importance of networks and approaches to patient and other stakeholder engagement. Implementation is often highly contextual and can benefit from stakeholder engagement and other assessments. Our FACE approach provides stakeholder questions and language to inform guideline implementation and tools.

CONCLUSION

The FACE criteria propose a series of knowledge translation questions to guide the assessment of implementation for evidence-based guidelines. It is desirable for guideline developers to use a conceptual approach, such as FACE, to tailor implementation and inform end of guideline dissemination and knowledge translation activities.

Screening for abdominal aortic aneurysm in patients with clinically manifest vascular disease

AIMS

Declining prevalence of abdominal aortic aneurysm (AAA) might force a more targeted screening approach (high-risk populations only) in order to maintain (cost-)effectiveness. We aimed to determine temporal changes in the prevalence of screening-detected AAA, to assess AAA-related surgery, and evaluate all-cause mortality in patients with manifest vascular disease.

METHODS AND RESULTS

We included patients with manifest vascular disease but without a history of AAA enrolled in the ongoing single-centre prospective UCC-SMART cohort study. Patients were screened at baseline for AAA by abdominal ultrasonography. We calculated sex- and age-specific prevalence of AAA, probability of survival in relation to the presence of AAA, and the proportion of patients undergoing AAA-related surgery. Prevalence of screening-detected AAA in 5440 screened men was 2.5% [95% confidence interval (CI) 2.1-2.9%] and in 1983 screened women 0.7% (95% CI 0.4-1.1%). Prevalence declined from 1997 until 2017 in men aged 70-79 years from 8.1% to 3.2% and in men aged 60-69 years from 5.7% to 1.0%. 36% of patients with screening-detected AAA received elective AAA-related surgery during follow-up (median time until surgery = 5.3 years, interquartile range 2.5-9.1). Patients with screening-detected AAA had a lower probability of survival (sex and age adjusted) compared to patients without screening-detected AAA (51%, 95% CI 41-64% vs. 69%, 95% CI 68-71%) after 15 years of follow-up.

CONCLUSION

The prevalence of screening-detected AAA has declined over the period 1997-2017 in men with vascular disease but exceeds prevalence in already established screening programs targeting 65-year-old men. Screening for AAA in patients with vascular disease may be cost-effective, but this remains to be determined.

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.

Evaluating the Use of a Generic Three-Dimensionally (3D) Printed Abdominal Aortic Aneurysm Model as an Adjunct Patient Education Tool

An abdominal aortic aneurysm (AAA) is a serious medical condition that requires invasive surgery or endovascular treatment with stent grafts. This procedure is primarily carried out by vascular surgeons and interventional radiologists. Current methods of educating patients about their procedure have been inadequate, causing unnecessary stress in patients who have this condition and seek treatment.

In this study, we evaluate a three-dimensionally (3D) printed AAA model to use as an adjunct patient education tool, thus allowing patients to make a more knowledgeable decision when providing informed consent. The physical attributes and realism of the model are evaluated through the use of a quantitative and qualitative survey completed by physicians at St. Clare’s Mercy Hospital in St. John’s, Newfoundland. These physicians are referred to as “Experts” in our study and also rate and comment on the necessity of having patient-specific versus generic 3D AAA models for patient education purposes.

The aim of this study is to determine whether our 3D printed AAA model is ready to be used as an adjunct patient education tool and to seek suggestions for improvements that can be made in the model. Furthermore, having generic 3D AAA models would significantly decrease healthcare costs as compared to patient-specific models. Thus, we also investigate if generic models would suffice from the perspective of the physicians.

Appropriateness of Abdominal Aortic Aneurysm Screening With Ultrasound: Potential Cost Savings With Guideline Adherence and Review of Prior Imaging

OBJECTIVE

To assess the appropriateness of abdominal aortic aneurysm (AAA) screening with ultrasound (US) and potential cost savings by adhering to guidelines and reviewing prior imaging.

METHODS

Screening aortic US performed in Nova Scotia from January 1 to April 30, 2019, were reviewed. Patient sex, age, risk factors, and study result (negative, <2.5 cm; ectatic, 2.5-2.9 cm; positive for AAA, ≥3 cm) were recorded. Previous imaging tests were reviewed for the presence/absence of aortic ectasia or aneurysm. Appropriateness was based on the Canadian Task Force on Preventive Health Care (CTFPHC) and the Canadian Society of Vascular Surgery (CSVS) guidelines. The number of potentially averted US, subsequent missed positive findings, and cost savings (over the 4-month period) were calculated according to: 1) each guideline; and 2) each guideline combined with review of imaging done 0 to 5 years and 0 to 10 years previously.

RESULTS

There were 17 (4.6%) of 369 ectatic aortas and 18 (4.9%) of 369 AAAs. The number of potentially averted examinations, missed ectatic aortas, missed AAAs, and cost savings were as follows, respectively: CTFPHC, 222 (60.2%) of 369, 8, 7, and CAD$20 501.70; CSVS, 117 (31.7%) of 369, 4, 2, and CAD$10 804.95. The model that would yield the greatest cost savings and fewest missed positive findings was the combination of CSVS guidelines with review of prior imaging within 5 years; this would avert 189 (51.2%) of 369 examinations, save CAD$17 454.15 over 4 months, and miss only 2 AAAs and 2 ectatic aortas.

CONCLUSION

Over half of aortic US screening tests can be safely averted by adhering to CSVS guidelines and reviewing imaging performed within 5 years.

Gender medicine: Towards a gender-specific treatment of neuropsychiatric disorders

Sex and gender are increasingly recognized as major influencing factors in disorders across all medical specialties. Even though there is ample evidence of sex and gender differences in neuropsychiatric disorders, a sex and gender-differentiated approach has not yet been sufficiently applied to diagnostics and management. Therefore, there is an urgent need to establish general recommendations and guidelines toward precision and sex/gender medicine, with regard to dosage, tolerability, interactions and side effects, sensitivity of diagnostic tests, and distinct treatment strategies. This chapter illustrates the current knowledge about sex and gender aspects in neuropsychiatric disorders, providing a base not only to assist the clinician in the handling of specific pathologic entities, but also to sensitize medical practitioners to consider sex and gender in clinical decision-making. As such, the chapter is a call to action to physicians and researchers to produce more sex- and gender-stratified evidence, leading to an acceleration of guideline development. Such novel guidelines will provide a base for medical education, of both medical students and specialists, as well as a reference point for practitioners, toward precision medicine.

Retrospective review of abdominal aortic aneurysm deaths in New Zealand: what proportion of deaths is potentially preventable by a screening programme in the contemporary setting?

OBJECTIVES

To describe the proportions of people dying from abdominal aortic aneurysm (AAA) who might have benefited from a formal screening programme for AAA.

DESIGN

Retrospective cross-sectional review of deaths.

SETTING AND STUDY POPULATIONS

All AAA deaths registered in New Zealand from 2010 to 2014 in the absence of a national AAA screening programme.

MAIN OUTCOME MEASURES

Known history of AAA prior to the acute event leading to AAA death, prognosis limiting comorbidities, history of prior abdominal imaging and a validated multimorbidity measure (M3-index scores).

RESULTS

1094 AAA deaths were registered in the 5 years between 2010 and 2014 in New Zealand. Prior to the acute AAA event resulting in death, 31.3% of the cohort had a known AAA diagnosis, and 10.9% had a previous AAA procedure. On average, the AAA diagnosis was known 3.7 years prior to death. At least 77% of the people dying from AAA also had one or more other prognosis limiting diagnosis. The hazard of 1-year mortality associated with the non-AAA related comorbidities for the AAA cohort aged 65 or above were 1.5-2.6 times higher than to the age matched general population based on M3-index scores. In 2014, overall AAA deaths accounted for only 0.7% of total deaths, and 1.0% of deaths among men aged 65 or above in New Zealand. At most, 20% of people dying from AAA in New Zealand between 2010 and 2014 might have had the potential to derive full benefit from a screening programme. About 51% of cases would have derived no or very limited benefit from a screening programme.

CONCLUSION

Falling AAA mortality, and high prevalence of competing comorbidities and/or prior AAA diagnosis and procedure raises the question about the likely value of a national AAA screening programme in a country such as New Zealand.

Sex-Specific Considerations in Guidelines Generation and Application

New knowledge about male-female differences in pathophysiology, diagnosis, and treatment is shifting the practice of medicine from a one-size-fits all approach to a more individualized process that considers sex-specific interventions at the point of care. In this article, we review how clinical practice guideline committees can incorporate a structured framework to determine whether sex-specific assessments of the quality of the evidence or the particular recommendations should be made. The process can be operationalized by societies who author clinical practice guidelines by developing formal policies to approach biological sex in a systematic way, and by ensuring that writing committees include an individual who will champion the formal appraisal of the literature for associations between sex and the outcomes of interest. Ongoing challenges are discussed, and solutions are provided for how to disaggregate the evidence, how to assess bias, how to improve search strategies, and what to do when the data are insufficient to make sex-specific recommendations. Application of sex-specific recommendations will involve routinely asking whether the presentation, diagnostic workup, or management might change for each patient if they were the opposite sex.