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- Högberg, Dominika, et al.
(author)
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Carotid Artery Atherosclerosis Among 65-year-old Swedish Men : A Population-based Screening Study
- 2014
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In: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 48:1, s. 5-10
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Journal article (peer-reviewed)abstract
- Objective: There are limited contemporary epidemiological data on the prevalence of carotid atherosclerosis in the general population. The aim was to determine the prevalence of and risk factors associated with carotid artery atherosclerosis among 65-year-old men. Methods: This was a population-based screening study. All 65-year-old men in the County of Uppsala, Sweden, who attended screehing for abdominal aortic aneurysm (AAA) 2007-2009, were invited for duplex scanning of the carotid arteries. Results: Of 4801 men invited, 4657 (97%) accepted. Carotid plaques (>2 x 6 mm) were observed in 1169 (25%) men, 94 (2.0%) had carotid stenoses (50-99%), and 15 (0.3%) had occluded carotid arteries. In a multivariate logistic regression model, smoking (OR 1.7, 95% CI 1.5-1.9), hypertension (1.5, 95% CI 1.3-1.7), diabetes mellitus (1.2, 95% CI 1.0-1.5), and coronary artery disease (1.5, 95% CI 1.3-1.8) were associated with prevalence of carotid atherosclerosis (plaque and/or stenosis). The use of antiplatelet agents and statins in participants with a carotid plaque was 20% and 29%, respectively. The corresponding figures in participants with a stenosis were 42% and 41%. Conclusions: This study offers contemporary data on the prevalence of carotid atherosclerosis in a population-based cohort of 65-year-old men. Most of those at risk had no other clinical manifestation of atherosclerosis, and therefore had no secondary prevention.
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| 2. |
- Högberg, Dominika, et al.
(author)
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Clinical effect and cost effectiveness of screening for asymptomatic carotid stenosis : A Markov model
- 2018
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In: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 55:6, s. 819-827
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Journal article (peer-reviewed)abstract
- Objectives: Screening for asymptomatic carotid artery stenosis (ACAS) is controversial. The cost-effectiveness of screening depends on screening cost, ACAS prevalence, and the potential stroke reducing effect of best medical treatment (BMT). The aim of the study was to determine the threshold values for these parameters in order for screening for ACAS to be cost-effective. Material and methods: The clinical effect and cost-effectiveness of ultrasound-screening for ACAS with subsequent initiation of BMT versus not screening, was assessed in a Markov model with a life-time perspective. Key parameters; including stroke risk, all-cause mortality, and costs were based on contemporary published data, population statistics and ongoing screening programs. Prevalence of ACAS and rate of ongoing BMT was based on data from a population recently screened for ACAS. Minimum required stroke-risk reduction from BMT, incremental cost-efficiency ratio (ICER), absolute risk reduction for stroke (ARR), number needed to screen (NNS) were calculated. Results: Screening was cost-effective at an ICER of €5744 per incremental quality adjusted life-year (QALY) gained. ARR was 135 per 100000 screened, NNS was 741 and QALYs gained were 6700 per 100000 invited. At a willingness-to-pay (WTP) threshold of €50,000 per QALY the minimum required stroke risk reduction from BMT was 22%. The assumed degree of stroke risk reduction was the most important determinant of cost-efficiency. Conclusion: A moderate (22%) reduction in the risk of stroke from BMT was required for an ACAS screening strategy to be cost-effective at WTP of €50,000/QALY. Targeting populations with higher prevalence of ACAS could improve cost-efficiency.
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| 3. |
- Högberg, Dominika, et al.
(author)
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Five-year outcomes in men screened for carotid artery stenosis at 65 years of age : a population-based cohort study
- 2019
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In: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 57:6, s. 759-766
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Journal article (peer-reviewed)abstract
- Objectives: The aim was to determine the prognosis of 65-year old men five years after carotid ultrasound screening, as well as risk factors for disease progression.Material and methods: All 65-year-old men living in the county of Uppsala 2007-2009 were invited to an ultrasound examination of both carotid arteries and re-invited at age 70. The cohort was grouped into: normal carotids, plaque without significant stenosis, moderate stenosis (50-79%), and severe stenosis (80-99%). The rates of disease progression to death, significant stenosis, and neurological events were assessed, as well as risk factors and medication.Results: Among men participating in carotid screening at age 65, 3057 were re-screened at age 70. In those with normal carotids (n=2318), 23 (1.0%) progressed to a moderate, and four (0.2%) developed a symptomatic severe stenosis. Among those with plaque (n=696), 25 (3.6%) progressed to moderate, and eight (1.1%) to severe stenosis, of whom four (0.6%) had symptoms. Of 31 with 50-79% stenosis, four (12.9%) had progressed to a severe stenosis, of whom two (6.5%) developed symptoms. Five of twelve subjects (42%) with 80-99% stenosis developed symptoms. Disease regression was present among 306 (41.4%) men. In multivariable analysis, smoking, coronary artery disease and hypercholesterolemia were associated with disease progression. The proportions of antiplatelet, statin and antihypertensive treatment in the population at age 70 were 22%, 29% and 55% respectively.Conclusion: Men with plaques and moderate stenosis have a good prognosis, but in those with severe stenosis there was a high risk of neurological events.
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| 4. |
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| 5. |
- Högberg, Dominika
(author)
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Screening for asymptomatic carotid atherosclerosis
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Ischemic stroke is the most common cause of handicap in adults and the third most common cause of death in Sweden. Internal carotid artery atherosclerosis is an important cause and accounts for 20% of ischemic strokes. Screening for carotid atherosclerosis has been debated over the past two decades.The aims of this thesis were (I) to study the prevalence of and risk factors associated with carotid artery atherosclerosis among 65 year old men, (II) to evaluate a simplified ultrasound protocol (the grayscale/mosaic method) for the exclusion of significant carotid artery stenosis for screening purpose, (III) to evaluate the required effect of primary preventive therapy in reducing risk of stroke among patients with asymptomatic carotid disease in order for screening to be cost-effective and (IV) to study natural history of carotid atherosclerosis and outcome five years after screening in 65-year old men.The prevalence of atherosclerotic plaques was high (25%), while the prevalence of >50% stenosis was relatively low (2.0%). Smoking, hypertension, diabetes mellitus and coronary artery disease were independent risk factors and individuals with several risk factors had a higher prevalence of stenosis. Most of those at risk were not on any preventive medication. A simplified grayscale/mosaic method was found to have a high negative predictive value for significant carotid stenosis. The minimum stroke risk reduction effect required for preventive intervention to be cost effective was 22%. Carotid atherosclerotic plaque and stenosis 50-79% has a relatively benign development during five years if treated with BMT and risk factor adjustment. Very few progressed to symptomatic disease. More severe stenosis (80-99%) had higher rate of neurological events, and may benefit from additional intervention.In conclusion, prevalence of silent atherosclerotic disease in carotid arteries was common among 65-year-old men. Most of those at risk had no secondary prevention. There is a simple DUS method that could be used for screening purpose. Screening for carotid disease is only cost-effective if the preventive strategy lowers the risk of stroke by 22%. Men with plaques and moderate stenosis have a good prognosis, but among those with severe stenosis there is a need for further intervention.
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| 6. |
- Högberg, Dominika, et al.
(author)
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Simplified ultrasound protocol for the exclusion of clinically significant carotid artery stenosis
- 2016
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In: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 121:3, s. 165-169
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Journal article (peer-reviewed)abstract
- Objectives: To evaluate a simplified ultrasound protocol for the exclusion of clinically significant carotid artery stenosis for screening purposes. Material and methods: A total of 9,493 carotid arteries in 4,748 persons underwent carotid ultrasound examination. Most subjects were 65-year-old men attending screening for abdominal aortic aneurysm. The presence of a stenosis on B-mode and/or a mosaic pattern in post-stenotic areas on colour Doppler and maximum peak systolic velocity (PSV) in the internal carotid artery (ICA) were recorded. A carotid stenosis was defined as The North American Symptomatic Carotid Endarterectomy Trial (NASCET) >20% and a significant stenosis as NASCET >50%. The kappa (kappa) statistic was used to assess agreement between methods. Sensitivity, specificity, positive predictive (PPV), and negative predictive (NPV) values were calculated for the greyscale/mosaic method compared to conventional assessment by means of PSV measurement. Results: An ICA stenosis was found in 121 (1.3%) arteries; 82 (0.9%) were graded 20%-49%, 16 (0.2%) were 50%-69%, and 23 (0.2%) were 70%-99%. Eighteen (0.2%) arteries were occluded. Overall, the greyscale/mosaic protocol showed a moderate agreement with ICA PSV measurements for the detection of carotid artery stenosis, x=0.455. The sensitivity, specificity, PPV, and NPV for detection of >20% ICA stenosis were 91% (95% CI 0.84-0.95), 97% (0.97-0.98), 31% (0.26-0.36), and 97% (0.97-0.97), respectively. The corresponding figures for >50% stenosis were 90% (0.83-0.95), 97% (0.97-0.98), 11% (0.08-0.15), and 100% (0.99-1.00). Conclusion: Compared with PSV measurements, the simplified greyscale/mosaic protocol had a high negative predictive value for detection of >50% carotid stenosis, suggesting that it may be suitable as a screening method to exclude significant disease.
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