Size thresholds for repair of abdominal aortic aneurysms warrant reconsideration.

BACKGROUND: The historical size threshold for abdominal aortic aneurysm (AAA) repair is widely accepted to be 5.5 cm for men and 5.0 cm for women. However, contemporary AAA rupture risks may be lower than historical benchmarks, which has implications for when AAAs should be repaired. Our objective was to use contemporary AAA rupture rates to inform optimal size thresholds for AAA repair. METHODS: We used a Markov chain analysis to estimate life expectancy for patients with AAA. The primary outcome was AAA-related mortality. We estimated survival using Social Security Administration life tables and published contemporary AAA rupture estimates. For those undergoing repair, we modified survival estimates using data from the Vascular Quality Initiative and Medicare on complications, late rupture, and open conversion. We used this model to estimate the AAA repair size threshold that minimizes AAA-related mortality for 60-year-old average-health men and women. We performed a sensitivity analysis of poor-health patients and 70- and 80-year-old base cases. RESULTS: The annual risk of all-cause mortality under surveillance for a 60-year-old woman presenting with a 5.0 cm AAA using repair thresholds of 5.5 cm, 6.0 cm, 6.5 cm, and 7.0 cm was 1.7%, 2.3%, 2.7%, and 2.8%, respectively. The corresponding risk for a man was 2.3%, 2.9%, 3.3%, and 3.4% for the same repair thresholds, respectively. For a 60-year-old average-health woman, an AAA repair size of 6.1 cm was the optimal threshold to minimize AAA-related mortality. Life expectancy varied by <2 months for repair at sizes from 5.7 cm to 7.1 cm. For a 60-year-old average-health man, an AAA repair size of 6.9 cm was the optimal threshold to minimize AAA-related mortality. Life expectancy varied by <2 months for repair at sizes from 6.0 cm to 7.4 cm. Women in poor health, at various age strata, had optimal AAA repair size thresholds that were >6.5 cm, whereas men in poor health, at all ages, had optimal repair size thresholds that were >8.0 cm. CONCLUSIONS: The optimal threshold for AAA repair is more nuanced than a discrete size. Specifically, there appears to be a range of AAA sizes for which repair is reasonable to minmized AAA-related mortality. Notably, they all are greater than current guideline recommendations. These findings would suggest that contemporary AAA size thresholds for repair should be reconsidered.

Racial disparities in treatment of ruptured abdominal aortic aneurysms.

OBJECTIVE: The Society for Vascular Surgery has recommended immediate transfer of patients with ruptured abdominal aortic aneurysms (rAAAs) to a regional center when feasible. However, Black patients might be less likely to be transferred and more likely to be turned down for repair. We, therefore, examined the transfer rates, turndown rates, and outcomes for Black vs White patients presenting with rAAAs in two large databases. METHODS: We examined all rAAA repairs in the Vascular Quality Initiative from 2003 to 2020 to evaluate the transfer rates and outcomes for Black vs White patients. We used the National Inpatient Sample from 2004 to 2015 to examine the turndown rates. Mixed effects logistic regression, Cox regression, and marginal effects modeling were used to study the interaction between race, insurance status, surgery type (open repair vs endovascular aortic aneurysm repair), and hospital volume. RESULTS: We identified 4935 patients with rAAAs in the Vascular Quality Initiative (6.2% Black) and 48,489 in the National Inpatient Sample (6.0% Black). The rates of transfer were high; however, Black patients were significantly less likely to undergo transfer before repair compared with White patients (49% Black vs 62% White; P = .002). The result was consistent in both crude and adjusted analyses when considering only stable patients and was not modified by insurance status, surgery type, or hospital volume. No significant differences were found in perioperative mortality (22% vs 26%; P = .098) or complications (52% vs 52%; P = .64). However, Black patients were significantly more likely to be turned down for repair (37% vs 28%; odds ratio, 1.5; 95% confidence interval, 1.2-1.9; P < .001). A significant interaction was found between race and insurance status with respect to turndown. Patients with private insurance had undergone surgery at a similar rate, regardless of race. However, among patients with Medicare or Medicaid/self-pay, Black patients were less likely than were White patients to undergo repair (Medicare, 64% vs 72%; P = .001; Medicaid/self-pay, 43% vs 61%; P = .031). Patients with Medicaid/self-pay were also less likely to undergo repair than were patients of the same race with either Medicare or private insurance (P < .05). CONCLUSIONS: We found that Black patients with rAAAs are poorly served by the current systems of interhospital transfer in the United States, because they less often undergo transfer before repair. Although the postoperative outcomes appeared similar, this finding could be falsely optimistic, because Black patients, especially the underinsured, were turned down for repair more often even after adjustment. Significant work is needed to better understand the reasons underlying these disparities and identify the targets to improve the care of Black patients with rAAAs.

Long-term Outcomes Associated With Open vs Endovascular Abdominal Aortic Aneurysm Repair in a Medicare-Matched Database.

Importance: Endovascular aneurysm repair is associated with a significant reduction in perioperative mortality and morbidity compared with open aneurysm repair in the treatment of abdominal aortic aneurysm. However, this benefit decreases over time owing to increased reinterventions and late aneurysm rupture after endovascular repair. Objective: To compare long-term outcomes of endovascular vs open repair of abdominal aortic aneurysm. Design, Setting, and Participants: This multicenter retrospective cohort study used deidentified data with 6-year follow-up from the Medicare-matched Vascular Quality Initiative Vascular Implant Surveillance and Interventional Outcomes Network database. Patients undergoing first-time elective endovascular or open abdominal aortic aneurysm repair from 2003 to 2018 were propensity score matched. Patients with ruptured abdominal aortic aneurysm, concomitant procedures, or prior history of abdominal aortic aneurysm repair, were excluded. Data were analyzed from January 1, 2003, to December 31, 2018. Exposures: First-time elective endovascular or open repair for abdominal aortic aneurysm. Main Outcomes and Measures: The primary long-term outcome of interest was 6-year all-cause mortality, rupture, and reintervention. Secondary outcomes included 30-day mortality and perioperative complications. Results: Among a total of 32 760 patients (median [IQR] age, 75 [70-80] years; 25 706 [78.5%] men) who underwent surgical abdominal aortic aneurysm repair, 28 281 patients underwent endovascular repair and 4479 patients underwent open repair. After propensity score matching, there were 2852 patients in each group. Open repair was associated with significantly lower 6-year mortality compared with endovascular repair (548 deaths [35.6%] vs 608 deaths [41.2%]; hazard ratio [HR], 0.83; 95% CI, 0.74-0.94; P = .002), with increases in mortality starting from 1 to 2 years (84 deaths [4.3%] vs 126 deaths [6.7%]; HR, 0.63; 95% CI, 0.48-0.83; P = .001) and 2 to 6 years (211 deaths [25.8%] vs 241 deaths [30.6%]; HR, 0.73; 95% CI, 0.61-0.88; P = .001). Open repair, compared with endovascular repair, also was associated with significantly lower rates of 6-year rupture (117 participants [5.8%] vs 149 participants [8.3%]; HR, 0.76; 95% CI, 0.60-0.97; P < .001) and reintervention (190 participants [11.6%] vs 267 participants [16.0%]; HR, 0.67; 95% CI, 0.55-0.80; P < .001). Open repair was associated with significantly higher odds of 30-day mortality (OR, 3.56; 95% CI, 2.41-5.26; P < .001) and complications. Conclusions and Relevance: These findings suggest that overall mortality after elective abdominal aortic aneurysm repair was higher with endovascular repair than open repair despite reduced 30-day mortality and perioperative morbidity after endovascular repair. Endovascular repair additionally was associated with significantly higher rates of long-term rupture and reintervention. These findings emphasize the importance of careful patient selection and long-term follow-up surveillance for patients who undergo endovascular repair.

Modelling the impact of changes to abdominal aortic aneurysm screening and treatment services in England during the COVID-19 pandemic.

BACKGROUND: The National Health Service (NHS) abdominal aortic aneurysm (AAA) screening programme (NAAASP) in England screens 65-year-old men. The programme monitors those with an aneurysm, and early intervention for large aneurysms reduces ruptures and AAA-related mortality. AAA screening services have been disrupted following COVID-19 but it is not known how this may impact AAA-related mortality, or where efforts should be focussed as services resume. METHODS: We repurposed a previously validated discrete event simulation model to investigate the impact of COVID-19-related service disruption on key outcomes. This model was used to explore the impact of delayed invitation and reduced attendance in men invited to screening. Additionally, we investigated the impact of temporarily suspending scans, increasing the threshold for elective surgery to 7cm and increasing drop-out in the AAA cohort under surveillance, using data from NAAASP to inform the population. FINDINGS: Delaying invitation to primary screening up to two years had little impact on key outcomes whereas a 10% reduction in attendance could lead to a 2% lifetime increase in AAA-related deaths. In surveillance patients, a 1-year suspension of surveillance or increase in the elective threshold resulted in a 0.4% increase in excess AAA-related deaths (8% in those 5-5.4cm at the start). Longer suspensions or a doubling of drop-out from surveillance would have a pronounced impact on outcomes. INTERPRETATION: Efforts should be directed towards encouraging men to attend AAA screening service appointments post-COVID-19. Those with AAAs on surveillance should be prioritised as the screening programme resumes, as changes to these services beyond one year are likely to have a larger impact on surgical burden and AAA-related mortality.

Late outcomes after endovascular and open repair of large abdominal aortic aneurysms.

OBJECTIVE: The risk of aortic abdominal aneurysm (AAA) rupture increases with an increasing aneurysm diameter. However, the effect of the AAA diameter on late outcomes after aneurysm repair is unclear. Therefore, we assessed the association of a large AAA diameter with late outcomes for patients undergoing open and endovascular AAA repair. METHODS: We identified all patients who had undergone elective open or endovascular infrarenal aneurysm repair from 2003 to 2016 in the Vascular Quality Initiative linked to Medicare claims for long-term outcomes. A large AAA diameter was defined as a diameter >65 mm. We assessed the 5-year reintervention, rupture, mortality, and follow-up rates. We constructed propensity scores and used inverse probability-weighted Kaplan-Meier estimations and Cox proportional hazard models to identify independent associations between large AAA repair and our outcomes. RESULTS: Of the 21,119 aneurysm repairs identified, 15.2% were for large AAAs. Of the 21,119 repairs, 19,017 were endovascular and 2102 were open. The large AAA cohort was less likely to have undergone endovascular aneurysm repair (EVAR; 84.9% vs 91%; P < .001), more likely to be older (median age, 76 vs 75 years; P < .001), and were less likely to be women (16.2% vs 21.7%; P < .001). After EVAR, patients with large AAAs had had lower adjusted 5-year freedom from reintervention (73.9% vs 84.6%; P < .001), freedom from rupture (88.5% vs 93.6%; P < .001), survival (58.0% vs 66.4%; P < .001), and freedom from loss to follow-up (77.7% vs 83.3%; P < .001) compared with patients with smaller AAAs. However, after open repair, the adjusted 5-year freedom from reintervention (95.8% vs 93.3%; P = .11), freedom from rupture (97.4% vs 97.8%; P = .32), survival (70.4% vs 74.0%; P = .13), and loss to follow-up (60.5% vs 62.8%; P = .86) were similar to the results for patients with smaller AAAs. For patients with large AAAs, the adjusted 5-year survival was lower after EVAR than that after open repair (55.3% vs 63.7%) but not after smaller AAA repair (67.3% vs 70.6%). CONCLUSIONS: The 5-year adjusted reintervention, ruptures, mortality, and loss to follow-up rates for patients who had undergone large AAA EVAR were higher than those for patients who had undergone small AAA EVAR and large AAA open repair. Therefore, for patients with large AAAs who are medically fit, open repair should be strongly considered. Furthermore, these findings highlight the necessity for rigorous long-term follow-up after EVAR.

Optimizing Surveillance and Re-intervention Strategy Following Elective Endovascular Repair of Abdominal Aortic Aneurysms.

BACKGROUND: EVAR for abdominal aortic aneurysm has an initial survival advantage over OR, but more frequent complications increase costs and long-term aneurysm-related mortality. Randomized controlled trials of EVAR versus OR have shown EVAR is not cost-effective over a patient's lifetime. However, in the EVAR-1 trial, postoperative surveillance may have been sub-optimal, as the importance of sac growth as a predictor of graft failure was overlooked. METHODS: Real-world data informed a discrete event simulation model of postoperative outcomes following EVAR. Outcomes observed EVAR-1 were compared with those from 5 alternative postoperative surveillance and re-intervention strategies. Key events, quality-adjusted life years and costs were predicted. The impact of using complication and rupture rates from more recent devices, imaging and re-intervention methods was also explored. RESULTS: Compared with observed EVAR-1 outcomes, modeling full adherence to the EVAR-1 scan protocol reduced abdominal aortic aneurysm (AAA) deaths by 3% and increased elective re-interventions by 44%. European Society re-intervention guidelines provided the most clinically effective strategy, with an 8% reduction in AAA deaths, but a 52% increase in elective re-interventions. The cheapest and most cost-effective strategy used lifetime annual ultrasound in primary care with confirmatory computed tomography if necessary, and reduced AAA-related deaths by 5%. Using contemporary rates for complications and rupture did not alter these conclusions. CONCLUSIONS: All alternative strategies improved clinical benefits compared with the EVAR-1 trial. Further work is needed regarding the cost and accuracy of primary care ultrasound, and the potential impact of these strategies in the comparison with OR.

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.

Editor's Choice - Assessment of Correlation Between Mean Size of Infrarenal Abdominal Aortic Aneurysm at Time of Intact Repair Against Repair and Rupture Rate in Nine Countries.

OBJECTIVE: This study aimed to analyse the mean abdominal aortic aneurysm (AAA) diameter for repair in nine countries, and to determine variation in mean AAA diameter for elective AAA repair and its relationship to rupture AAA repair rates and aneurysm related mortality in corresponding populations. METHODS: Data on intact (iAAA) and ruptured infrarenal AAA (rAAA) repair for the years 2010-2012 were collected from Denmark, England, Finland, Germany, Hungary, New Zealand, Norway, Sweden, and the USA. The rate of iAAA repair and rAAA per 100 000 inhabitants above 59 years old, mean AAA diameter for iAAA repair and rAAA repair, and the national rates of rAAA were assessed. National cause of death statistics were used to estimate aneurysm related mortality. Direct standardisation methods were applied to the national mortality data. Logistic regression and analysis of variance model adjustments were made for age groups, sex, and year. RESULTS: There was a variation in the mean diameter of iAAA repair (n = 34 566; range Germany = 57 mm, Denmark = 68 mm). The standardised iAAA repair rate per 100000 inhabitants varied from 10.4 (Hungary) to 66.5 (Norway), p<.01, and the standardised rAAA repair rate per 100 000 from 5.8 (USA) to 16.9 (England), p<.01. Overall, there was no significant correlation between mean diameter of iAAA repair and standardised iAAA rate (r2 = 0.04, p = .3). There was no significant correlation between rAAA repair rate (n = 12 628) with mean diameter of iAAA repair (r2 = 0.2, p = .1). CONCLUSION: Despite recommendations from learned society guidelines, data indicate variations in mean diameter for AAA repair. There was no significant correlation between mean diameter of AAA repair and rates of iAAA repair and rAAA repair. These analyses are subject to differences in disease prevalence, uncertainties in rupture rates, validations of vascular registries, causes of death and registrations.

A Novel Quality of Life Instrument for Patients with an Abdominal Aortic Aneurysm.

OBJECTIVE: The surveillance and treatment of abdominal aortic aneurysms (AAAs) may impact patient quality of life (QOL). A novel AAA specific QOL instrument was developed and validated to quantify the impact of AAA surveillance on QOL. METHODS: The study was performed in two phases: development (2011-2013) and validation (2013-2014) of a survey instrument. Content was informed by focus groups at three centres (22 patients) and two multidisciplinary physician focus groups (6 vascular surgeons, 7 primary care providers). Cognitive interviews (17 patients) ensured questions were understood as intended. The final survey was mailed to AAA patients at six US institutions. Patients were scored on two AAA specific domains of QOL: emotional impact (EIS) and behavioural change (BCS), range 0-100 with higher scores indicating worse quality of life. Test retest reliability and internal consistency were assessed. Discriminant validity was determined by comparing scores between patients under surveillance vs. those who had undergone AAA repair. Scores were externally validated by correlation with the Short Form (SF)-12. RESULTS: A total of 1,008 (73%) of 1,373 patients returned surveys: 351 (35%) were under surveillance, 657 (65%) had undergone repair (endovascular, 414; open, 179; unsure, 64). Median EIS was 11 (range 0-95; IQR 7-26). Median BCS was 13 (range 0-100; IQR 9-47). To test reliability, 337 patients repeated the survey after four weeks with no significant differences between scores over time. EIS and BCS demonstrated good internal consistency (Cronbach's Alpha 0.85 and 0.75 respectively). There was strong correlation between scores (r = 0.53) and both related moderately to SF-12 scores (r = 0.45 and r = 0.39, respectively). Patients under AAA surveillance had worse EIS than repair patients (22 vs. 13; p < .001). Patients with a higher perceived rupture risk had a worse EIS (45 vs. 12; p < .001) and BCS (30 vs. 13; p < .001). CONCLUSIONS: An AAA specific QOL instrument was successfully created and validated. The range of impact on QOL by AAA surveillance is broad. For most patients the impact is minimal, but for some, especially those with a greater perceived rupture risk, it is severe.

Select early type IA endoleaks after endovascular aneurysm repair will resolve without secondary intervention.

OBJECTIVE: Although it is traditionally considered ominous, the natural history of early proximal attachment site endoleaks (IA) after endovascular aneurysm repair (EVAR) is not well known. Our aim was to identify risk factors for persistent type IA endoleaks and to determine their effect on long-term outcomes after EVAR. METHODS: All patients who underwent infrarenal EVAR at a single institution between 1998 and 2015 were identified. Preoperative axial imaging and intraoperative arteriograms were reviewed, and those patients with a type IA endoleak were further studied. Aneurysm features were characterized by two reviewers and were studied for predictors of persistent endoleaks at the conclusion of the case. Patient records and the Social Security Death Index were used to record 1-year and overall survival. RESULTS: We identified 1484 EVARs, 122 (8%) of which were complicated by a type IA endoleak on arteriography after graft deployment, with a median follow-up of 4 years. The majority of patients underwent additional ballooning of the proximal site (52 [43%]) or placement of an aortic cuff (47 [39%]); 30 patients (25%) received a Palmaz stent, and four patients were treated with coils or anchors. At case end, only 43 (35%) of the type IA endoleaks remained; at 1 month, only 16 endoleaks persisted (13%), and only six persisted at 1 year (6%). In multivariable analysis, the only independent predictor of persistence of type IA endoleak at the conclusion of the case was the presence of extensive neck calcifications (odds ratio [OR], 9.9; 95% confidence interval [CI], 1.4-67.9; P = .02). Thirteen patients (11%) underwent reintervention for type IA endoleaks, with a time frame ranging from 3 days postoperatively to 11 years. There were three patients (2.4%) who experienced aneurysm rupture. Postoperative type IA endoleak was associated with lower survival at 1 year (79% vs 91%; relative risk, 2.5; 95% CI, 1.1-5.4; P = .02), but it did not affect long-term survival (log-rank, P = .45). Both an increase in aneurysm sac size and failure of the endoleak to resolve by case end were independent predictors of a need for reintervention (growth: OR, 8.3; 95% CI, 2.2-31.6; P < .01; persistent endoleak: OR, 7.6; 95% CI, 1.8-31.5; P < .01). A persistent type IA endoleak was not independently associated with an increase in sac size on surveillance imaging (P = .28). CONCLUSIONS: Aneurysm rupture secondary to persistent type IA endoleak is rare, and most will resolve within 1 year. Extensive neck calcification is the only independent predictor of persistent type IA endoleak, and an increase in sac size warrants reintervention. These data suggest that select early persistent type IA endoleaks can be safely observed.

Economic evaluation in the context of rare diseases: is it possible? / Evaluación económica en el contexto de enfermedades raras: ¿es posible? / Avaliação econômica no âmbito das doenças raras: isto é possível?

This study analyzes the available evidence on the adequacy of economic evaluation for decision-making on the incorporation or exclusion of technologies for rare diseases. The authors conducted a structured literature review in MEDLINE via PubMed, CRD, LILACS, SciELO, and Google Scholar (gray literature). Economic evaluation studies had their origins in Welfare Economics, in which individuals maximize their utilities based on allocative efficiency. There is no widely accepted criterion in the literature to weigh the expected utilities, in the sense of assigning more weight to individuals with greater health needs. Thus, economic evaluation studies do not usually weigh utilities asymmetrically (that is, everyone is treated equally, which in Brazil is also a Constitutional principle). Healthcare systems have ratified the use of economic evaluation as the main tool to assist decision-making. However, this approach does not rule out the use of other methodologies to complement cost-effectiveness studies, such as Person Trade-Off and Rule of Rescue.

El objetivo fue sistematizar las evidencias disponibles sobre la pertinencia de utilizar la evaluación económica para la incorporación/exclusión de tecnología en enfermedades raras. Se realizó una revisión sistemática de la literatura en MEDLINE vía PubMed, CRD, LILACS, SciELO y Google Académico (literatura gris). Los estudios de evaluación económica se originan de la Economía del Bienestar, en la que los individuos maximizan sus utilidades, basándose en la eficiencia de asignación. No existe un criterio ampliamente aceptado para examinar las utilidades, a fin de dar más peso a los individuos con mayores necesidades. Generalmente, los estudios no equilibran asimétricamente las utilidades, todas son consideradas iguales, lo que en Brasil es también un principio constitucional. Los sistemas de salud han ratificado el uso de la evaluación económica como la principal herramienta para ayudar en la toma de decisiones. Sin embargo, este abordaje no excluye el uso de otras metodologías complementarias a los estudios de coste-efectividad, como la técnica de compensación personal o la regla del rescate.

O objetivo deste estudo foi analisar as evidências disponíveis sobre a adequação do uso de avaliação econômica sobre incorporação/exclusão de tecnologias para doenças raras. Foi realizada uma revisão estruturada da literatura, nas bases MEDLINE, via PubMed, CRD, LILACS, SciELO e Google Acadêmico (literatura cinzenta). Os estudos de avaliação econômica têm origem na Economia do Bem-Estar, na qual os indivíduos maximizam suas utilidades, fundamentando-se na eficiência alocativa. Não há um critério amplamente aceito para ponderar as utilidades esperadas, no sentido de dar mais peso aos indivíduos com maiores necessidades em saúde. Geralmente não se ponderam assimetricamente as utilidades; todas são tratadas de forma igualitária, que, no caso brasileiro, também é um princípio constitucional. Os sistemas de saúde têm ratificado o uso de avaliação econômica como principal instrumento para auxiliar na tomada de decisão. No entanto, essa postura não exclui o uso de outras metodologias complementares aos estudos de custo-efetividade, como Person Trade-Off e regra de resgate.

Quality assessment of elective abdominal aortic aneurysm repair from referral to surgery.

BACKGROUND: The risk of rupture for a large (≥ 55 mm) abdominal aortic aneurysm(AAA) is significant and therefore operative treatment should take place before possible aneurysm rupture. Timing of elective AAA surgery has rarely been investigated previously. The aim of this study is to evaluate success in the elective treatment process of large AAAs from referral to surgery in Helsinki University Central Hospital. PATIENTS AND METHODS: We retrospectively analyzed all 361 patients who were assigned for elective treatment of AAA during 2005 - 2010. We divided the patients into subgroups according to size of the aneurysm: <60 mm, 61 - 70 mm and >70 mm. The main focus was set on the preoperative period and on potential factors causing delay. End points indicating failure in the treatment process were aneurysm ruptures and deaths before surgery. RESULTS: The median time from referral to surgery for the three subgroups was 112, 91 and 45 days respectively (p < 0,001). There were no significant differences between the treatment methods: open repair (OR) with 103 days and endovascular aortic repair (EVAR) with 113 days until surgery. Twenty three (6.4 %) patients were operated on emergency basis while waiting for the operation, six of them for ruptured aneurysm. There were an additional five patients with aneurysm ruptures who all died, as did four out the six operated ones. CONCLUSIONS: The whole treatment process starting from the referral should be considered in order for elective AAA treatment to succeed. Recommendations should be established for the preoperative period to guarantee rapid preoperative evaluation.

A new aortic injury score predicts early rupture more accurately than clinical assessment.

OBJECTIVE: The optimal timing for repair of a high-grade blunt thoracic aortic injury (BTAI) is uncertain. Delayed repair is common and associated with improved outcomes, but some lesions may rupture during observation. To determine optimal patient selection for appropriate management, we developed a pilot clinical risk score to evaluate aortic stability and predict rupture. METHODS: Patients presenting in stable condition with Society for Vascular Surgery grade III or IV BTAI diagnosed on computed tomography (CT) were retrospectively reviewed. To determine clinical and radiographic factors associated with aortic rupture, patients progressing to aortic rupture (defined by contrast extravasation on CT or on operative or autopsy findings) were compared with those who had no intervention ≤48 hours of admission. A model targeting 100% sensitivity for rupture was generated and internally validated by bootstrap analysis. Clinical utility was tested by comparison with clinical assessment by surgeons experienced in BTAI management who were provided with CT images and clinical data but were blinded to outcome. RESULTS: The derivation cohort included 18 patients whose aorta ruptured and 31 with stable BTAI. There was no difference in age, gender, injury mechanism, nonchest injury severity, blood pressure, or Glasgow Coma Scale on admission between patient groups. As dichotomous factors, admission lactate >4 mM, posterior mediastinal hematoma >10 mm, and lesion/normal aortic diameter ratio >1.4 on the admission CT were independently associated with aortic rupture. The model had an area under the receiver operator curve of .97, and in the presence of any two factors, was 100% sensitive and 84% specific for predicting aortic rupture. No aortic lesions ruptured in patients with fewer than two factors. In contrast, clinical assessment had lower accuracy (65% vs 90% total accuracy, P < .01). CONCLUSIONS: This novel risk score can be applied on admission using clinically relevant factors that incorporate patient physiology, size of the aortic lesion, and extent of the mediastinal hematoma. The model reliably identifies and distinguishes patients with high-grade BTAI who are at risk for early rupture from those with stable lesions. Although preliminary, because it is more accurate than clinical assessment alone, the score may improve patient selection for emergency or delayed intervention.

Gaps in preoperative surveillance and rupture of abdominal aortic aneurysms among Medicare beneficiaries.

OBJECTIVE: Screening and surveillance are recommended in the management of small abdominal aortic aneurysms (AAAs). Gaps in surveillance after early diagnosis may lead to unrecognized AAA growth, rupture, and death. This study investigates the frequency and predictors of rupture of previously diagnosed AAAs. METHODS: Data were extracted from Medicare claims for patients who underwent AAA repair between 2006 and 2009. Relevant preoperative abdominal imaging exams were tabulated up to 5 years prior to AAA repair. Repair for ruptured AAAs was compared with repair for intact AAAs for those with an early diagnosis of an AAA, defined as having received imaging at least 6 months prior to surgery. Gaps in surveillance were defined as no image within 1 year of surgery or no imaging for more than a 2-year time span after the initial image. Logistic regression was used to examine independent predictors of rupture despite early diagnosis. RESULTS: A total of 9298 patients had repair after early diagnosis, with rupture occurring in 441 (4.7%). Those with ruptured AAAs were older (80.2 ± 6.9 vs 77.6 ± 6.2 years; P < .001), received fewer images prior to repair (5.7 ± 4.1 vs 6.5 ± 3.5; P = .001), were less likely to be treated in a high-volume hospital (45.4% vs 59.5%; P < .001), and were more likely to have had gaps in surveillance (47.4% vs 11.8%; P < .001) compared with those receiving repair for intact AAAs. After adjusting for medical comorbidities, gaps in surveillance remained the largest predictor of rupture in a multivariate analysis (odds ratio, 5.82; 95% confidence interval, 4.64-7.31; P < .001). CONCLUSIONS: Despite previous diagnosis of AAA, many patients experience rupture prior to repair. Improved mechanisms for surveillance are needed to prevent rupture and ensure timely repair for patients with AAAs.

Current state of experimental imaging modalities for risk assessment of abdominal aortic aneurysm.

BACKGROUND: Abdominal aortic aneurysm (AAA) is a major cause of death in developed countries. Patients often lack clinical symptoms, most acute AAA patients do not survive rupture, and subsequent surgical repair has a significant postoperative mortality. Diagnostics for AAAs are currently centered on aneurysm diameter, but recent studies claim this method to be insufficiently accurate. More accurate diagnostic criteria need to be indentified to minimize the amount of unnecessary interventions and to provide earlier diagnosis of rupture-prone AAAs. METHODS: A literature study using the MEDLINE database followed by manual cross-referencing provided original studies concerning AAA diagnostics. RESULTS: The currently validated imaging modalities such as ultrasound, computed tomography, and magnetic resonance imaging allow AAA research to develop in several directions. Some studies investigate whether clinically visible entities like thrombus, calcification, and vascular anatomy could be implemented directly into clinical practice through use of ultrasound or computed tomography. Experimental studies on intravascular ultrasound, positron emission tomography-computed tomography, ultrasound particle image velocimetry and superparamagnetic particles in magnetic resonance imaging propose new methodologies to benefit AAA research. Other studies focus on available technology toward inflammation, metabolism, and the effects of hemodynamics on vascular integrity. CONCLUSIONS: Contradictory outcomes, low availability of experimental imaging modalities, and an often small population size hamper research in this field. Introducing new techniques and biomarkers in current or experimental modalities may prove to be the next step in the development of new diagnostic criteria for the risk assessment of AAA rupture. Until then, the AAA diameter remains the gold standard as a clinical risk factor.

Preliminary intraobserver and interobserver variability in wall stress and rupture risk assessment of abdominal aortic aneurysms using a semiautomatic finite element model.

OBJECTIVE: We investigated the intraobserver and interobserver variability of using semiautomatic finite element analysis to calculate the von Mises stress and peak wall rupture risk (PWRR) in patients with an abdominal aortic aneurysm (AAA) in longitudinal studies. METHODS: Four independent observers made 3-dimensional (3D) reconstructions, with minimal manual adjustments, of small AAAs (<5.0 cm) in 17 patients and processed finite element analysis. We used semiautomatic diagnostic software with a finite element model (A4research, VASCOPS GmbH, Graz, Austria). The finite element method was used to calculate von Mises stress and PWRR, which are indicators for wall stress. The differences of each pair of measurements of von Mises stress and PWRR were plotted against their mean and the difference of the mean, according to Bland-Altman analysis. RESULTS: The intraobserver variability had an overall mean percentage difference of 6.86% ± 6.46% for the von Mises stress and 7.70% ± 6.26% for PWRR. The interobserver variability for the four observers showed an overall mean percentage difference of 7.09% ± 6.16% for the von Mises stress and 9.47% ± 8.18% for the PWRR measurement. No significant differences were found (P < .05), for the von Mises stress and PWRR for all observers. CONCLUSIONS: The von Mises stress and PWRR of small AAAs calculated in this semiautomatic finite element analysis program show good interobserver and intraobserver variability. It is suitable for clinical use to evaluate mechanical aortic wall characteristics and to compare it with other current methods such as maximum aortic diameter measurements.

Radiographic monitoring of incidental abdominal aortic aneurysms: a retrospective population-based cohort study.

BACKGROUND: An abdominal aortic aneurysm (AAA) that is identified when the abdomen is imaged for some other reason is known as an incidental AAA. No population-based studies have assessed the management of incidental AAAs. The objective of this study was to measure the completeness of radiographic monitoring of incidental AAAs by means of a population-based analysis. METHODS: We linked a cohort of patients with incidental AAA (defined as a previously unidentified aortic enlargement exceeding 30 mm in diameter found in an imaging study performed for another reason) to various population-based databases. We followed the patients to elective repair or rupture of the aneurysm, death or 31 Mar. 2009. We used evidence-based monitoring guidelines to calculate the proportion of observation time during which each incidental AAA was incompletely monitored. We used negative binomial regression to determine the association of patient-related factors with this outcome. RESULTS: For the period between January 1996 and September 2008, we identified 191 patients with incidental AAA (mean diameter 37.6 mm, 95% confidence interval [CI] 36.6-38.6 mm; median follow-up 4.4 [range 0.6-12.7] years). Fifty-six of these patients (29.3%) had no radiographic monitoring of the aneurysm. Overall, patients spent one-fifth of their time with incomplete monitoring of the AAA (median 19.4%, interquartile range 0.3%-44.0%). Factors independently associated with incomplete monitoring included older age (relative rate [change in proportion of time with incomplete monitoring] [RR] 1.27, 95% CI 1.10-1.47, per decade), larger size (RR 1.65, 95% CI 1.38-2.01, per 10-mm increase) and detection of the aneurysm while the patient was in hospital or the emergency department (RR 1.34, 95% CI 1.00-1.79). Comorbidities were not associated with monitoring. INTERPRETATION: Radiographic monitoring of incidental AAAs was incomplete, and almost one-third of patients underwent no monitoring at all. Incomplete monitoring did not appear to be related to patients' comorbidity.

Cost-effectiveness of intensive smoking cessation therapy among patients with small abdominal aortic aneurysms.

INTRODUCTION: Smoking cessation is one of the few available strategies to decrease the risk for expansion and rupture of small abdominal aortic aneurysms (AAAs). The cost-effectiveness of an intensive smoking cessation therapy in patients with small AAAs identified at screening was evaluated. METHODS: A Markov cohort simulation model was used to compare an 8-week smoking cessation intervention with adjuvant pharmacotherapy and annual revisits vs nonintervention among 65-year-old male smokers with a small AAA identified at screening. The smoking cessation rate was tested in one-way sensitivity analyses in the intervention group (range, 22%-57%) and in the nonintervention group (range, 3%-30%). Literature data on the effect of smoking on AAA expansion and rupture was factored into the model. RESULTS: The intervention was cost-effective in all tested scenarios and sensitivity analyses. The smoking cessation intervention was cost-effective due to a decreased need for AAA repair and decreased rupture rate even when disregarding the positive effects of smoking cessation on long-term survival. The incremental cost/effectiveness ratio reached the willingness-to-pay threshold value of €25,000 per life-year gained when assuming an intervention cost of > €3250 or an effect of ≤ 1% difference in long-term smoking cessation between the intervention and nonintervention groups. Smoking cessation resulted in a relative risk reduction for elective AAA repair by 9% and for rupture by 38% over 10 years of follow-up. CONCLUSIONS: An adequate smoking cessation intervention in patients with small AAAs identified at screening can cost-effectively increase long-term survival and decrease the need for AAA repair.

Rural hospitals face a higher burden of ruptured abdominal aortic aneurysm and are more likely to transfer patients for emergent repair.

BACKGROUND: The influence of rural hospital location on abdominal aortic aneurysm (AAA) outcomes is unknown. We undertook a study to determine the difference in the risk of ruptured AAA presentation and outcomes after ruptured AAA between rural and urban areas. STUDY DESIGN: Patients in the Nationwide Inpatient Sample from 2001 to 2007, with intact AAA repair or ruptured AAA, were included. Patients transferred from another hospital, with unrecorded hospital ZIP code, or age less than 50 years were excluded. Health system variables were obtained from the Area Resource File. Vascular surgeon census was determined from the Society for Vascular Surgery online registry. Multivariable logistic regression was used to analyze outcomes in patients with AAA, adjusting for patient, hospital, and health system variables. RESULTS: Rural hospital location was associated with higher risk of ruptured AAA presentation (odds ratio [OR] 2.46, 95% CI 1.90 to 3.19) and transfer to another hospital without ruptured AAA repair (9.3% vs 1.4%, p < 0.001). The adjusted risk of death was similar for patients with ruptured AAA admitted to rural and urban hospitals (OR 0.96, 95% CI 0.73 to 1.27). Hospital elective AAA repair volume less than 15 was a risk factor for death after ruptured AAA. CONCLUSIONS: Rural hospitals face a disproportionate burden of ruptured AAA and are more likely to transfer patients with ruptured AAA without performing repair, compared with urban hospitals. Solutions to rural disparity in ruptured AAA outcomes should focus on improving rural patients' access to vascular surgeons for elective and emergent AAA repair.