Abdominal Aortic Aneurysm In Population Research Articles

Abdominal aortic aneurysm screening: are those at high-risk being overlooked?

An abdominal aortic aneurysm (AAA) is defined as enlargement of an abdominal aorta with a diameter of 3.0 cm or larger in the anteroposterior or transverse plane. In order to diagnose and treat this disease early, clinical trials were conducted to evaluate the benefits of ultrasound screening for AAA. There is enough good evidence to recommend AAA population ultrasound scan screening for men over 65 years old. Prevalence rates for AAA amongst males at age 65 detected by screening appear to be decreasing, however AAA screening continues to be cost effective. There has been emerging evidence suggesting a strong link between family history and development of AAA. The prevalence of AAA amongst family members has been higher when compared to general population. This high prevalence of AAA in the first-degree relatives provide a strong argument for aggressive approach to screening of this specific cohort. After the latest literature review, there have been no data from a single randomised clinical trial or large nonrandomised studies published with ‘targeted USS screening’ with regards to family history of AAA. Ultrasound screening for the first-degree relatives, both male and female, of patients with AAA appears to be feasible and cost effective. A pilot study to determine the prevalence of familial AAA amongst probands and the prevalence amongst first degree relatives should identify the unmet need for AAA screening for this cohort and quantify the resources required for a sustainable screening programme.

Trajectory Modelling to Assess Trends in Long-Term Readmission Rate among Abdominal Aortic Aneurysm Patients.

Introduction The aim of the study was to use trajectory analysis to categorise high-impact users based on their long-term readmission rate and identify their predictors following AAA (abdominal aortic aneurysm) repair. Methods. In this retrospective cohort study, group-based trajectory modelling (GBTM) was performed on the patient cohort (2006-2009) identified through national administrative data from all NHS English hospitals. Proc Traj software was used in SAS program to conduct GBTM, which classified patient population into groups based on their annual readmission rates during a 5-year period following primary AAA repair. Based on the trends of readmission rates, patients were classified into low- and high-impact users. The high-impact group had a higher annual readmission rate throughout 5-year follow-up. Short-term high-impact users had initial high readmission rate followed by rapid decline, whereas chronic high-impact users continued to have high readmission rate. Results Based on the trends in readmission rates, GBTM classified elective AAA repair (n=16,973) patients into 2 groups: low impact (82.0%) and high impact (18.0%). High-impact users were significantly associated with female sex (P=0.001) undergoing other vascular procedures (P=0.003), poor socioeconomic status index (P < 0.001), older age (P < 0.001), and higher comorbidity score (P < 0.001). The AUC for c-statistics was 0.84. Patients with ruptured AAA repair (n=4144) had 3 groups: low impact (82.7%), short-term high impact (7.2%), and chronic high impact (10.1%). Chronic high impact users were significantly associated with renal failure (P < 0.001), heart failure (P = 0.01), peripheral vascular disease (P < 0.001), female sex (P = 0.02), open repair (P < 0.001), and undergoing other related procedures (P=0.05). The AUC for c-statistics was 0.71. Conclusion Patients with persistent high readmission rates exist among AAA population; however, their readmissions and mortality are not related to AAA repair. They may benefit from optimization of their medical management of comorbidities perioperatively and during their follow-up.

Validez de la ecografía abdominal en Atención Primaria para detección de aneurisma de aorta abdominal en varones de entre 65 y 75 años

ObjectiveTo determine the usefulness of ultrasound examination in Primary Care (PC) for the detection of abdominal aortic aneurysm (AAA) in male patients from 65-75 years old, as well as the consistency between observers on the diagnosis between general practitioners and the reference specialty in this area, Vascular Surgery. To estimate the prevalence of AAA in that population and its association with risk factors. DesignCross-sectional descriptive study. LocationHealthcare Centres of Coto and Calzada II (Gijón, Spain). ParticipantsMales born between 1 January 1939 and 31 December 1950. InterventionsFrom the 2,511 males found, 407 were selected using stratified random sampling. Aortic diameter was measured, with those ≥3cm and 20% from the <3cm being referred for a second measurement by a vascular surgeon. VariablesDependent: presence/absence of aneurism. Independent: age, abdominal perimeter, smoking, arterial hypertension, diabetes, dyslipidaemia, familial cases of AAA, cerebrovascular accident, and coronary disease. The analysis was performed using Bayesian inference with models for proportions and a multivariate logistic regression. ResultsFrom 304 ultrasound scans performed, 13 were referred with suspicion of AAA, and 63 with were within normal. The sensitivity was 93.3% and specificity 98.5% with a 95% credibility interval (CredI) of 75.4-99.9%, and 94.3-100%, respectively. The prevalence was 4.6% (95% CredI: 2.5-7.2%, and the intraclass correlation coefficient between PC and Vascular Surgery was 0.88 (95% CredI: 0.79-0.94). Age, smoking, dyslipidaemia, and diabetes tended to increase the odds of prevalence of AAA. ConclusionThe ultrasound performed by GPs for the detection of AAA had high diagnostic validity. Further studies on the effectiveness should be conducted in order to assess the appropriateness of introducing a system of early detection of AAA in the risk population.

Systematic review and qualitative evidence synthesis of patient-reported outcome measures for abdominal aortic aneurysm

The aim was to identify and evaluate existing patient-reported outcome measures (PROMs) for use in patients with an abdominal aortic aneurysm (AAA) to inform the selection for use in surgical practice. Two reviews were conducted: a systematic review to identify valid, reliable and acceptable PROMs for patients with an AAA, and a qualitative evidence synthesis to assess the relevance to patients of the identified PROM items. PROM studies were evaluated for their psychometric properties using established assessment criteria, and for their methodological quality using the COSMIN checklist. Qualitative studies were synthesized using framework analysis, and concepts identified were then triangulated using a protocol with the item concepts of the identified PROMs. Four PROMs from three studies were identified in the first review: Short Form 36, Australian Vascular Quality of Life Index, Aneurysm Dependent Quality of Life (AneurysmDQoL) and Aneurysm Symptoms Rating Questionnaire (AneurysmSRQ). None of the identified PROMs had undergone a rigorous psychometric evaluation within the AAA population. Four studies were included in the qualitative synthesis, from which 28 concepts important to patients with an AAA were identified. The AneurysmDQoL and AneurysmSRQ together provided the most comprehensive assessment of these concepts. Fear of rupture, control, ability to forget about the condition and size of aneurysm were all concepts identified in the qualitative studies but not covered by items in the identified PROMs. Further research is needed to develop PROMs for AAA that are reliable, valid and acceptable to patients.

Low prevalence of abdominal aortic aneurysm in the Seychelles population aged 50 to 65 years : cardiovascular topics

The prevalence of abdominal aortic aneurysm (AAA) and its risk factors are well known in Western countries but few data are available from low- and middle- income countries. We are not aware of systematically collected population- based data on AAA in the African region. We evaluated the prevalence of AAA in a population- based cardiovascular survey conducted in the Republic of Seychelles in 2004 (Indian Ocean, African region). Among the 353 participants aged 50 to 64 years and screened with ultrasound, the prevalence of AAA was 0.3% (95% CI: 0- 0.9) and the prevalence of ectatic dilatations of the abdominal aorta was 1.5% (95% CI: 0.2- 2.8). The prevalence of AAA in the general population seemed lower in Seychelles than in Western countries, despite a high prevalence in Seychelles of risk factors of AAA, such as smoking (in men), high blood pressure and hypercholesterolaemia.

Surface Curvature as a Classifier of Abdominal Aortic Aneurysms: A Comparative Analysis

An abdominal aortic aneurysm (AAA) carries one of the highest mortality rates among vascular diseases when it ruptures. To predict the role of surface curvature in rupture risk assessment, a discriminatory analysis of aneurysm geometry characterization was conducted. Data was obtained from 205 patient-specific computed tomography image sets corresponding to three AAA population subgroups: patients under surveillance, those that underwent elective repair of the aneurysm, and those with an emergent repair. Each AAA was reconstructed and their surface curvatures estimated using the biquintic Hermite finite element method. Local surface curvatures were processed into ten global curvature indices. Statistical analysis of the data revealed that the L2-norm of the Gaussian and Mean surface curvatures can be utilized as classifiers of the three AAA population subgroups. The application of statistical machine learning on the curvature features yielded 85.5% accuracy in classifying electively and emergent repaired AAAs, compared to a 68.9% accuracy obtained by using maximum aneurysm diameter alone. Such combination of non-invasive geometric quantification and statistical machine learning methods can be used in a clinical setting to assess the risk of rupture of aneurysms during regular patient follow-ups.

Screening for abdominal aortic aneurysm in coronary care unit patients with acute myocardial infarction using portable transthoracic echocardiography

Patients with acute myocardial infarction (AMI) represent a high-risk population in which screening for abdominal aortic aneurysm (AAA) is recommended but only occasionally performed. Transthoracic echocardiography (TTE) may offer the unique opportunity to evaluate the cardiac function and to screen for AAA during the same examination. We aimed to evaluate the feasibility of AAA screening at bedside using a portable cardiac ultrasound (US) echo machine and to determine the prevalence of AAA in population with AMI. The AA diameter was measured at bedside at the end of a regular TTE performed in consecutive patients admitted for AMI in the coronary care unit using a portable echo machine (Vividi, General Electric). AAA was defined by a transverse diameter of ≥ 30 mm. We prospectively enrolled 193 patients (65 ± 11 years, 77% male). Measurement of the AA diameter was feasible in 93% and the duration was 3 ± 1 min. An AAA was observed in nine patients (4.7%) and the prevalence increased with age (7.7% after 60 years and 9.2% after 65 years). No AAA was observed in patients under 50 years old. Inter-observer variability between cardiologists using the portable US system was excellent (mean difference 1.8 ± 2.0 mm) as well as the accuracy compared with measurements performed by a radiologist using a dedicated vascular US system (mean difference 1.5 ± 1.3 mm). Overall, the prevalence of AAA was 4.7%, increased with age, and seems higher than expected in the 'same-aged population'. In regard to the simplicity, accuracy, and feasibility, screening for AAA during TTE (one cardiovascular shot) may be of value after AMI especially in elderly patients.

229 Screening for abdominal aortic aneurysm among patients admitted for acute myocardial infarction using portable transthoracic echocardiography

Background Abdominal aortic aneurysm (AAA) remains asymptomatic for many years but often revealed dramatically (inaugural rupture). Its relatively low prevalence in the general population (5.5% of men over 65 years) implies specific target population screening. Patients with acute myocardial infarction (AMI) represent a high-risk population in which screening for other atherosclerotic locations is recommended but is still often neglected. We aimed to evaluate the feasibility of AAA screening during routine transthoracic echocardiography (TTE) in patients with AMI using a portable echocardiography system and to determine the prevalence of AAA in this population. Methods We prospectively measured the size of the abdominal aorta at the end of a regular TTE performed at bedside in consecutive patients admitted for AMI in our intensive care unit using a portable TTE system (Vividi, General electric). AAA was defined by a transverse diameter 30 mm. Results One hundred and fifty two patients were enrolled (mean age 65 ± 14 years old, 78% of male). Measurement of the size of the abdominal aorta was feasible in 93% (10 patients had poor echogenicity) and time duration was 3 ± 1 min. Interobserver variability between cardiologists was good (1.7 ± 1 mm). Eight patients had an AAA (5.2%) and prevalence increases with age, 8.7% after 60 years, 10.3% after 65 years. No patient below 50 years old had an AAA. Conclusion In patients admitted for AMI, screening for AAA during TTE using a portable TTE system was fast and highly feasible. Despite a striking low prevalence of AAA in this high cardiovascular risk population, analyse of the abdominal aorta should be recommended during TTE (“one cardiovascular shot”) especially in elderly patients in regard to the simplicity, inocuity and availability of the present screening.

Prehospital HMG Co-A Reductase Inhibitor Use and Reduced Mortality in Ruptured Abdominal Aortic Aneurysm

The compounds 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (HMG Co-A reductase inhibitors, statins) are popular medications for the control of elevated serum cholesterol. Recent evidence has demonstrated a survival benefit to patients who take statins in the premorbid period with severe sepsis, septic shock, or severe trauma. We hypothesized that a similar benefit would be seen in patients with ruptured abdominal aortic aneurysm. We completed a retrospective review of patients with ruptured abdominal aortic aneurysm in our institution from January 2000 to December 2008. We compared age, gender, mortality rates, and Physiologic and Operative Severity Score for the enumeration of Mortality and Morbidity (POSSUM) scores for all patients who met inclusion and exclusion criteria. We compared hospital and ICU lengths of stay, cardiac morbidity, and number of cardiac events per patient between survivor groups with and without prehospital statin use. We compared mortality, cardiac morbidity, and gender using the Pearson chi-square test, Physiologic and Operative Severity Score for the enumeration of Mortality and Morbidity scores and age using the Student's t-test and lengths of stay using the Mann Whitney-U test. Mortality in the group without prehospital statin use was 63.8%, and in the group with prehospital statin use was 34.8% (p=0.018, odds ratio 0.30 to 0.11). Physiologic and Operative Severity Score for the enumeration of Mortality and Morbidity scores were similar between survivor groups with and without statin use and nonsurvivor groups with and without statin use. Hospital and ICU lengths of stay, cardiac morbidity, and number of cardiac events per patient were not statistically different among survivors. Prehospital statin use appears to be associated with a significant survival benefit in the ruptured abdominal aortic aneurysm population.

Invited commentary

The high-risk patient has been haunting us for years. Before the endovascular era, very few patients were actually denied open aneurysm repair on account of extensive cardiovascular comorbidity and the increased mortality this type of surgery would be associated with. With the advent of endovascular aneurysm repair (EVAR), things changed. Because this therapy was initially considered most appropriate for patients who had a prohibitive risk for open surgery, an epidemic of high-risk patients seemed to ensue. In the subsequent years, many efforts were made to define “high risk,” but a widely accepted definition could not be accomplished. Recently, the EVAR-2 trial generated renewed interest in the preoperative risk profile of abdominal aortic aneurysm (AAA) patients, as it concluded that EVAR offers no benefit for high-risk patients compared with best medical treatment. Unfortunately, the EVAR-2 trialists had also failed to agree upon a clear definition of their high-risk patients. The Glasgow Aneurysm Scale (GAS) is a simple score that can be calculated in the office without complex formulas. It provides a numerical score representing the preoperative risk profile of an AAA patient. In a retrospective study, Hirzalla et al aimed at an external validation of the GAS score as a predictor for postoperative mortality and major morbidity after elective open AAA repair. They conclude that the GAS is a valid predictor for postoperative mortality and morbidity, but that it should merely be used to identify low-risk patients and not to identify high-risk patients. Apart from this being a bit of a disappointment in itself (we are really after a score that defines high-risk), a few methodologic issues of this study and some other limitations of the GAS score need to be highlighted. The study population that was used to validate the GAS score consisted of patients who were all considered suitable for open repair between 1994 and 2003. It is very likely that in the same period, patients who were considered at high risk for open repair (by whatever criteria) were treated by EVAR in this institution. As a result, young, low-risk patients are probably over-represented in the current study population. Unfortunately, the authors also included juxtarenal and suprarenal AAA repairs. As this subgroup is responsible for three of the total five deaths, it obviously plays a major role in the study outcome. With only two deaths in the remaining 193 infrarenal AAA repairs, one thing is clear for these authors: they really do not need a scoring system to predict deaths, as their mortality rate of open AAA-repair is exceptionally good. The reader is left with the conclusion that GAS may be helpful in identifying low-risk patients for this infrarenal AAA population, while this seems to be based upon a study population void of high-risk patients. Furthermore, it is important to realize that age is a major driver of the GAS score. The typical median of AAA patients at the time of surgery is between 70 and 75, which means that almost half of all AAA patients considered for repair already fall into the high-risk GAS-category (>77 points) on account of their age alone. With a history cerebrovascular or renal disease, it becomes almost impossible for a patient to qualify as low risk. Fortunately, these risk factors are uncommon (13% and 6%, respectively, in the current study). Patients with myocardial disease can only qualify as low risk if they are in their 60s. It therefore must be questioned if GAS really offers a lot more predictive power than age alone. Not to mention the issue of corrected or improved cardiac disease not being accounted for in the GAS score, as appropriately addressed by the authors. In conclusion, the authors are to be commended for tackling a vital issue in current AAA practice. The GAS score is a clever and simple test that deserves further evaluation; however, it needs application in larger studies with a higher proportion of patients with significant risk factors.

Screening for Abdominal Aortic Aneurysm: A Best-Evidence Systematic Review for the U.S. Preventive Services Task Force

While the prognosis for abdominal aortic aneurysm (AAA) rupture is poor, ultrasound imaging is an accurate and reliable test for detecting AAAs before rupture. To examine the benefits and harms of population-based AAA screening. MEDLINE (1994 to July 2004) supplemented by the Cochrane Library, a reference list of retrieved articles, and expert suggestions. Randomized trials of AAA population screening, population studies of AAA risk factors, and data on adverse screening and treatment events from randomized trials and cohort studies. All studies were reviewed, abstracted, and rated for quality by using predefined criteria. The authors identified 4 population-based randomized, controlled trials of AAA screening in men 65 years of age and older. On the basis of meta-analysis, an invitation to attend screening was associated with a significant reduction in AAA-related mortality (odds ratio, 0.57 [95% CI, 0.45 to 0.74]). A meta-analysis of 3 trials revealed no significant difference in all-cause mortality (odds ratio, 0.98 [CI, 0.95 to 1.02]). No significant reduction in AAA-related mortality was found in 1 study of AAA screening in women. Screening does not appear to be associated with significant physical or psychological harms. Major treatment harms include an operative mortality rate of 2% to 6% and significant risk for major complications. The population screening studies focused on men and provided no information on racial or ethnic groups. No information was available on uninvited control group characteristics, so the importance of risk factors such as tobacco use or family history could not be assessed. Since all trials were conducted in countries other than the United States, generalizability to the U.S. population is uncertain. For men age 65 to 75 years, an invitation to attend AAA screening reduces AAA-related mortality.

Abdominal aortic aneurysm, Leriche's syndrome, inguinal herniation, and smoking.

We previously found an increase in serum proteolytic activity in smokers with direct inguinal herniation and a similar imbalance in smokers with abdominal aortic aneurysm (AAA), but not in smokers with Leriche's syndrome (LS). If the protease imbalance in the blood of smokers with AAA or herniation is a causal factor, these conditions should be associated. Therefore, we determined whether this is true using patients with LS as control subjects. The frequency of inguinal herniation was significantly higher in the AAA population (N = 341; 25.8%) than in patients with LS (N = 417; 14.6%). In addition, patients with AAA had more severe herniation (direct, bilateral, recurrent, or earlier onset) and had more pronounced leukocytosis (9,000/cu mm v 8,190/cu mm). These data suggest that increased blood proteolytic activity may play a role in the development of both AAA and adult inguinal herniation but not LS. Men who smoke manifest different systemic effects.