| 11. |
- Hager, Jakob, 1967-
(författare)
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Abdominal Aortic Aneurysm : Aspects on how to affect mortality from rupture
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abdominal Aortic Aneurysm (AAA) is a disease that mainly affects elderly men, and ruptured AAA (rAAA) is associated with a mortality of > 80%. AAA seldom gives any symptoms prior to rupture.The aims of this thesis were to investigate different aspects of how to affect mortality from rAAA.In Study I, we identified 849 patients treated for rAAA during 1987-2004, and studied the 30-day survival after surgery, depending on whether they came directly to the treating hospital (one-stop) or were transferred via another hospital (two-stop). A two-stop referral pattern resulted in a 27% lower population-based survival rate for patients 65-74 years of age. However, the consequences would be small even if a one-stop referral pattern could be generally accomplished, due to the huge over-all mortality related to rAAA, hence an argument to find and treat AAA before rupture, e.g. by screening.In Study II, we examined the AAA-prevalence and the risk factors for AAA among 70-year-old men. The screening-detected AAA-prevalence was 2.3%, thus less than half the predicted. The most important risk factor was smoking.In Study III, we compared the screening-detected AAA-prevalence, the attendance rate, and the rate of opportunistic detection of AAA, between almost 8000 65- and 6000 70-year-old men. There was no difference in the screening-detected prevalence; probably due to the fact that almost 40% of the AAAs among the 70-year-old were already known prior to screening, compared to roughly 25% in the 65-year-old. The attendance rate was higher among the 65-year-old men, 85.7% compared 84.0% in the 70-year-old. Thus, there is no benefit of screening for AAA among 70- instead of 65-year-old men.In Study IV, a cost-effectiveness analysis, we found that screening for AAA still appears to be cost-effective, despite profound changes in disease pattern and AAA-management.In conclusion, we found that mortality from rAAA is not affected in any substantial way by different referral patterns and hence centralisation of services for AAA/rAAA is not a solution. A better alternative is to prevent rupture through early detection by screening. Screening 65-year-old men for AAA still appears to be cost-effective, despite profound changes in disease pattern and AAA-management during the last decade. Screening 70- instead of 65-year-old men will not increase the efficacy of screening.
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| 12. |
- Hager, Jakob, et al.
(författare)
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Changing Conditions - the same Conclusion : Cost-effective to Screen for Abdominal Aortic Aneurysm among 65-year-old Men, based on Data from an Implemented Screening Programme
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: Health economic analyses based on randomized trials have shown that screening for abdominal aortic aneurysm (AAA) cost-effectively decreases AAA-related as well as allcause mortality. However, results from running screening programmes now reveal substantially changed conditions in terms of prevalence, attendance rate, costs and mortality after intervention. Our aim was to evaluate whether screening for AAA among 65-year-old men on a general basis is cost-effective under current clinical practice.Methods: A decision-analytic model, previously used to show the cost-effectiveness of an AAA-screening programme before decision to introduce screening in practice, was updated using results from implemented screening-programmes as well as data from contemporary published data and the Swedvasc registry.Results: The base-case analysis showed that the cost per life-year gained and quality-adjusted life year (QALY) gained were 3252 € and 4231 €, respectively. The probability of screening being cost-effective was high.Conclusion: Despite profound changes in disease pattern and AAA-management, the current results are similar to those reported almost 10 years ago, and thus screening 65-year-old men for AAA still appears to be cost-effective.
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| 13. |
- Hager, Jakob, et al.
(författare)
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Lower Prevalence than Expected when Screening 70-year-old Men for Abdominal Aortic Aneurysm
- 2013
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 46:4, s. 453-459
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundScreening 65-year-old men for abdominal aortic aneurysms (AAA) is a cost-effective method to reduce the mortality from ruptured AAA. However, contemporary results show a lower than expected prevalence of AAA, thus questioning the benefit of screening. Since the prevalence increases with age, a possible way to enhance the benefit of screening might be to screen older men. Our aim was to determine the contemporary screening-detected prevalence among 70-year-old men.MethodsA total of 5,623 unscreened 70-year-old men were invited to ultrasound screening. Uni- and multivariable analyses were used to assess the risk factors for AAA.ResultsThe attendance rate was 84.0%. The prevalence of previously unknown AAAs was 2.3%. When adding the 64 men with an already known AAA to the screening-detected ones, the total prevalence in the population was at least 3.0%, and the previously discovered AAAs constituted 37.4% of the total prevalence. “Ex smoker” and “Current smoker” were the most important risk factors.ConclusionsWhen screening 70-year-old men for AAA, the prevalence was less than half that expected, despite a high attendance rate. Smoking was the strongest risk factor. Almost 40% of the men with AAAs were already known from other means than screening.
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| 14. |
- Hager, Jakob, et al.
(författare)
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No benefit of screening for abdominal aortic aneurysm among 70- instead of 65-year-old men
- 2014
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Ingår i: International Angiology. - : EDIZIONI MINERVA MEDICA. - 0392-9590. ; 33:5, s. 474-479
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Screening 65-year-old men for abdominal aortic aneurysm (AAA) reduces mortality from ruptured AAA (rAAA). Lower than expected prevalence of AAA is now found, why screening at a higher age and rescreening has been discussed. Our aim was to determine if screening at 70 years of age, instead of 65, increases clinical effectiveness.Methods: 7951 and 5623 previously un-screened 65- and 70-year old men were invited to ultrasound screening.Results: The attendance rate was 85.7% and 84.0%, p<0.01, for the 65- and 70-year old men respectively. The screening-detected prevalence did not differ, being 1.9% and 2.3%, p=0.15, respectively, probably due to the fact that 23.5% and 37.4% of all known AAA among 65- and 70-year-old men, were detected by other means prior to screening, p<0.01. However, the total known prevalence differed between the age-groups, being at least 2.1% and 3.0% respectively, p<0.001.Conclusion: The screening-detected AAA-prevalence did not differ between 65- and 70-yearold men, due to the greater number of AAA known prior to screening among 70- compared to 65-year-old men. Screening men at 70 instead of 65 years of age would not result in detection of substantially more previously unknown AAA, thus not preventing rAAA and consequently not more saved life-years. Further, data also indicates that it is questionable if re-screening the 65-year-old male population after five years would generate any important clinical effect.
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| 15. |
- Hager, Jakob, 1967-, et al.
(författare)
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Population-based survival rate with a one- or two-stop referral pattern for patients with ruptured abdominal aortic aneurysms
- 2013
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Ingår i: International Journal of Angiology. - Turin, Italy : Edizioni Minerva Medica. - 0392-9590 .- 1827-1839. ; 32:5, s. 492-500
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Tidskriftsartikel (refereegranskat)abstract
- AIM:Is there a difference in the population-based survival rate for patients with ruptured abdominal aortic aneurysms (rAAA), handled by a "one-stop" or a "two-stop" referral pattern?METHODS:Ten regions in Sweden were identified where clear-cut "one-stop" or "two-stop" referral-patterns prevailed. From the Swedvasc Registry we identified 849 patients operated on for rAAA, 1987 to 2004, living in any of these ten regions, and related the number of survivors to the whole population served by each hospital.RESULTS:The population-based survival rate was 14% lower for patients following a "two-stop" compared to a "one-stop" referral pattern (P=0.084). For the group 65-74 years-of-age the difference was significant (P=0.021), but no corresponding effect was seen regarding operative mortality rate or sex.CONCLUSION:Compared to a "one-stop" referral pattern for rAAA, a "two-stop" referral pattern results in a lower population-based survival rate for patients 65-74 years old, but the consequences would be small even if a "one-stop" referral pattern could be generally accomplished.
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| 16. |
- Hager, Jakob, et al.
(författare)
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Revisiting the cost-effectiveness of screening 65-year-old men for abdominal aortic aneurysm based on data from an implemented screening programme.
- 2017
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Ingår i: International Journal of Angiology. - : Edizioni Minerva Medica. - 0392-9590 .- 1827-1839. ; 36:6, s. 517-525
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Health economic analyses based on randomized trials have shown that screening for abdominal aortic aneurysm (AAA) cost-effectively decreases AAA-related, as well as all- cause mortality. However, follow-up from implemented screening programmes now reveal substantially changed conditions in terms of prevalence, attendance rate, costs and mortality after intervention. Our aim was to evaluate whether screening for AAA among 65-year-old men is cost-effective based on contemporary data on prevalence and attendance rates from an ongoing AAA screening programme.METHODS: A decision-analytic model, previously used to analyse the cost-effectiveness of an AAA screening programme prior to implementation in clinical practice, was updated using data collected from an implemented screening programme as well as data from contemporary published data and the Swedish register for vascular surgery (Swedvasc).RESULTS: The base-case analysis showed that the cost per life-year gained and quality-adjusted life year (QALY) gained were €4832 and €6325, respectively. Based on conventional threshold values of cost-effectiveness, the probability of screening being cost-effective was high.CONCLUSION: Despite the reduction of AAA-prevalence and changes in AAA-management over time, screening 65-year-old men for AAA still appears to yield health outcomes at a cost below conventional thresholds of cost-effectiveness.
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| 17. |
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| 18. |
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| 19. |
- Heby, Margareta, et al.
(författare)
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Relationship between mismatch repair immunophenotype and long-term survival in patients with resected periampullary adenocarcinoma
- 2018
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Ingår i: Journal of Translational Medicine. - : Springer Science and Business Media LLC. - 1479-5876. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Periampullary adenocarcinomas, including pancreatic cancer, are a heterogeneous group of tumors with poor prognosis, where classification into intestinal type (I-type) or pancreatobiliary type (PB-type) is a relevant prognostic factor. The clinical significance of deficient mismatch repair (dMMR) in periampullary adenocarcinoma is comparatively unexplored. Herein, we examined the associations of MMR immunophenotype with long-term survival in patients with resected periampullary adenocarcinoma, with particular reference to morphology and adjuvant treatment response. Methods: MMR protein expression was assessed by immunohistochemistry on tissue microarrays with primary tumors from a retrospective cohort of 175 patients with periampullary adenocarcinoma treated with pancreaticoduodenectomy during 2001-2011 in Malmö and Lund University Hospitals, Sweden. Cox proportional hazards models were applied to calculate hazard ratios (HR) and 95% confidence intervals (CI). Results: After a mean follow-up of 46.5 (1.9-185.1) months, 35 patients (20.3%) were alive, 24 with I-type and 11 with PB-type tumors. MMR protein expression could be evaluated in 172 cases, in which dMMR was denoted in 20 (11.6%) cases, 13/63 (20.6%) in I-type and 7/109 (6.4%) in PB-type tumors. dMMR was associated with a significantly prolonged overall survival in the entire cohort (HR=0.28, 95% CI 0.13-0.57), and in I-type tumors (HR=0.20, 95% CI 0.06-0.68), however not independent of conventional prognostic factors. In PB-type tumors, dMMR was not prognostic, but there was a significant negative interaction between dMMR and adjuvant treatment (pinteraction=0.015). Conclusions: dMMR is more frequent in I-type compared to PB-type periampullary adenocarcinoma, and is a prognostic factor for long-term survival only in the former. The finding of the small number of PB-type tumors with dMMR potentially lacking benefit from adjuvant chemotherapy is however noteworthy and merits further validation.
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| 20. |
- Helander, Jakob, et al.
(författare)
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Reflection-Based Source Inversion for Sparse Imaging of Low-Loss Composite Panels
- 2020
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 68:6, s. 4860-4870
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a bistatic reflection-based imaging technique for electromagnetic testing of conductor-backed composite panels, which is based on an inverse formulation of the numerical problem at hand, and technically extends a previously demonstrated transmission-based system. The technique exploits the a priori assumption of pixel-based sparsity and retrieves the final image using data from only a single measurement, thereby removing the necessity of a reference measurement to be conducted. To demonstrate the capability of the technique, retrieved images are presented for a synthetic proof-of-concept device under test and an industrially manufactured composite panel. The presented technique can be considered as the initial model in the development of more complex bistatic imaging systems and has been developed for the purpose of extending the opportunities to conduct reflection-based electromagnetic nondestructive testing on aircraft structural components.
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