| 11. |
- Ljungberg, Johan, et al.
(författare)
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Early impairment of renal function (shrunken pore syndrome) is associated with increased risk for future surgery for aortic stenosis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Introduction Renal insufficiency is a known risk factor for cardiovascular disease. However, it is unknown if early impairment in renal function is associated with increased risk for aortic stenosis (AS). Recently a new approach was proposed to detect early impairment in renal function by using the ratio between glomerular filtration rate (GFR) calculated by cystatin C and GFR calculated by creatinine. Purpose To evaluate if the ratio between GFR cystatin C and GFR creatinine is associated with increased risk for AS requiring surgery and further, to evaluate if the ratio associates with survival. Methods We identified 334 patients that underwent surgery for AS after participation in population surveys (median age (interquartile range) 59.4 (10.3) years at survey and 68.3 (12.7) at surgery, 48% females). For each patient, two matched referents were allocated. Circulating levels of cystatin C and creatinine were determined at baseline (survey). Estimated glomerular filtration rates (eGFR) were calculated using the CAPA and Lund-Malmö-Revised formulas. Uni- and multivariable conditional logistic regression analyses were used to estimate the risk (odds ratio (OR) with [95% confidence interval]) related to one (ln) standard deviation increase in cystatin C, creatinine, eGFR cystatin C, eGFR creatinine, and in the ratio between eGFR cystatin C and eGFR creatinine, respectively. Results A high ratio was associated with lower risk for AS requiring surgery (OR 0.84 [0.73–0.97]). After stratification for sex, this effect was seen in women but not in men (0.74 [0.60–0.92] and 0.93 [0.76 [0.76–1.13], respectively). After further stratification for CAD, the association remained in women with CAD, but the effect was not seen in men with CAD (0.60 [0.44–0.83] and 0.96 [0.76 [0.75–1.23]). A high ratio was associated with longer survival in the entire cohort (HR 0.84 [0.75–0.95]). Conclusion A high ratio between eGFR based on cystatin C and eGFR based on creatinine was associated with lower risk for surgery for AS in those with CAD with a clear sex-difference. Early renal impairment is thus associated with future risk for AS requiring surgery. Further, a high ratio relates to longer survival.
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| 12. |
- Ljungberg, Johan, et al.
(författare)
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Lipoprotein(a) and the Apolipoprotein B/A1 Ratio Independently Associate With Surgery for Aortic Stenosis Only in Patients With Concomitant Coronary Artery Disease
- 2017
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Ingår i: Journal of the American Heart Association. - : John Wiley & Sons. - 2047-9980. ; 6:12
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Aortic stenosis (AS) has different clinical phenotypes, including AS with or without concomitant coronary artery disease (CAD). It is unknown whether these phenotypes share the same risk factors. In particular, lipoprotein(a) [Lp(a)] and apolipoproteins (Apo) are associated with AS, but it is unknown whether these associations differ among phenotypes. In this prospective analysis we examined the impact of Lp(a) and Apo in subgroups of patients with AS.METHODS AND RESULTS: We identified 336 patients (mean age at survey 56.7 years, 48% female) who underwent surgery for AS after a median 10.9 years (interquartile range 9.3 years), participants in 1 of 3 large population surveys. For each patient, 2 matched referents were allocated. Lp(a) and Apo were analyzed in the baseline samples. Uni- and multivariable logistic regression analyses were used to estimate risks related to a 1 (ln) standard deviation increase in Lp(a) and the ratio of Apo B to Apo A1 (Apo B/A1 ratio). High levels of Lp(a) predicted surgery for AS in 203 patients with concomitant CAD (odds ratio [95% confidence intervals]) (1.29 [1.07-1.55]), but not in 132 patients without CAD (1.04 [0.83-1.29]) in the fully adjusted model. Similarly, a high Apo B/A1 ratio predicted surgery in patients with concomitant CAD (1.43 [1.16-1.76]) but not in those without CAD (0.87 [0.69-1.10]).CONCLUSIONS: High levels of Lp(a) and a high Apo B/A1 ratio were associated with surgery for AS in patients with concomitant CAD but not in those with isolated AS. This finding may lead to a new avenue of research for targeted risk factor interventions in this population.
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| 13. |
- Ljungberg, Johan, et al.
(författare)
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Mild impairment of renal function (shrunken pore syndrome) is associated with increased risk for future surgery for aortic stenosis
- 2019
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Taylor & Francis. - 0036-5513 .- 1502-7686. ; 79:7, s. 524-530
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Tidskriftsartikel (refereegranskat)abstract
- Recently, a new approach was proposed to detect mild impairment in renal function: a reduced ratio between estimated glomerular filtration rate (eGFR) calculated by cystatin C and eGFR calculated by creatinine. We aimed to evaluate if this ratio is associated with aortic stenosis (AS) requiring surgery. We identified 336 patients that first participated in population surveys and later underwent surgery for AS (median age [interquartile range] 59.8 [10.3] years at survey and 68.3 [12.7] at surgery, 48% females). For each patient, two matched referents were allocated. Cystatin C and creatinine were determined in stored plasma. eGFR(cystatin C) and eGFR(creatinine) and their ratio were estimated. Conditional logistic regression analyses were used to estimate the risk (odds ratio (OR) with [95% confidence interval (CI)]) related to one (ln) standard deviation increase in the ratio between eGFR(cystatin C) and eGFR(creatinine). A high ratio was associated with lower risk for AS requiring surgery (OR [95% CI]) (OR 0.84 [0.73-0.97]), especially in women (0.74 [0.60-0.92] vs. 0.93 [0.76-1.13] in men). After further stratification for coronary artery disease (CAD), the association remained in women with CAD but not in women without CAD (0.60 [0.44-0.83] and 0.89 [0.65-1.23], respectively). In conclusion, a high ratio between eGFR(cystatin C) and eGFR(creatinine) was associated with lower risk for surgery for AS, especially in women. Mild impairment of renal function is thus associated with future risk for AS requiring surgery.
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| 14. |
- Ljungberg, Johan, et al.
(författare)
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Proteomic Biomarkers for Incident Aortic Stenosis Requiring Valvular Replacement
- 2018
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Ingår i: Circulation. - : LIPPINCOTT WILLIAMS & WILKINS. - 0009-7322 .- 1524-4539. ; 138:6
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Tidskriftsartikel (refereegranskat)abstract
- Background: Aortic valve stenosis (AS) is the most common indication for cardiac valve surgery; untreated AS is linked to high mortality. The etiological background of AS is unknown. Previous human studies were typically based on case-control studies. Biomarkers identified in prospective studies could lead to novel mechanistic insights. Methods: Within a large population survey with blood samples obtained at baseline, 334 patients were identified who later underwent surgery for AS (median age [interquartile range], 59.9 [10.4] years at survey and 68.3 [12.7] at surgery; 48% female). For each case, 2 matched referents were allocated. Plasma was analyzed with the multiplex proximity extension assay for screening of 92 cardiovascular candidate proteins. Conditional logistic regression models were used to assess associations between each protein and AS, with correction for multiple testing. A separate set of 106 additional cases with 212 matched referents was used in a validation study. Results: Six proteins (growth differentiation factor 15, galectin-4, von Willebrand factor, interleukin 17 receptor A, transferrin receptor protein 1, and proprotein convertase subtilisin/kexin type 9) were associated with case status in the discovery cohort; odds ratios ranged from 1.25 to 1.37 per SD increase in the protein signal. Adjusting the multivariable models for classical cardiovascular risk factors at baseline yielded similar results. Subanalyses of case-referent triplets (n=133) who showed no visible coronary artery disease at the time of surgery in the index person supported associations between AS and growth differentiation factor 15 (odds ratio, 1.40; 95% confidence interval, 1.10-1.78) and galectin-4 (odds ratio, 1.27; 95% confidence interval, 1.02-1.59), but these associations were attenuated after excluding individuals who donated blood samples within 5 years before surgery. In triplets (n=201), which included index individuals with concurrent coronary artery disease at the time of surgery, all 6 proteins were robustly associated with case status in all sensitivity analyses. In the validation study, the association of all but 1 (interleukin 17 receptor A) of these proteins were replicated in patients with AS with concurrent coronary artery disease but not in patients with AS without coronary artery disease. Conclusions: We provide evidence that 5 proteins were altered years before AS surgery and that the associations seem to be driven by concurrent atherosclerotic disease.
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| 15. |
- Nohlert, Johan, 1987, et al.
(författare)
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Global monitoring of fluidized-bed processes by means of microwave cavity resonances
- 2014
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Ingår i: Measurement: Journal of the International Measurement Confederation. - : Elsevier BV. - 0263-2241. ; 55, s. 520-535
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Tidskriftsartikel (refereegranskat)abstract
- We present an electromagnetic measurement system for monitoring of the effective permittivity in closed metal vessels, which are commonly used in the process industry. The measurement system exploits the process vessel as a microwave cavity resonator and the relative change in its complex resonance frequencies is related to the complex effective permittivity inside the vessel. Also, thermal expansion of the process vessel is taken into account and we compensate for its influence on the resonance frequencies by means of a priori information derived from a set of temperature measurements. The sensitivities, that relate the process state to the measured resonance frequencies, are computed by means of a detailed finite element model. The usefulness of the proposed measurement system is successfully demonstrated for a pharmaceutical fluidized-bed process, where the water and solid contents inside the process vessel is of interest.
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| 16. |
- Nyström, Mattias, et al.
(författare)
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Detection of windthrown trees using airborne laser scanning
- 2014
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Ingår i: International Journal of Applied Earth Observation and Geoinformation. - : Elsevier BV. - 0303-2434 .- 1569-8432. ; 30, s. 21-29
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a method has been developed for the detection of windthrown trees under a forest canopy, using the difference between two elevation models created from the same high density (65 points/m(2)) airborne laser scanning data. The difference image showing objects near the ground was created by subtracting a standard digital elevation model (DEM) from a more detailed DEM created using an active surface algorithm. Template matching was used to automatically detect windthrown trees in the difference image. The 54 ha study area is located in hemi-boreal forest in southern Sweden (Lat. 58 degrees 29' N, Long. 13 degrees 38' E) and is dominated by Norway spruce (Picea abies) with 3.5% deciduous species (mostly birch) and 1.7% Scots pine (Pinus sylvestris). The result was evaluated using 651 field measured windthrown trees. At individual tree level, the detection rate was 38% with a commission error of 36%. Much higher detection rates were obtained for taller trees; 89% of the trees taller than 27 m were detected. For pine the individual tree detection rate was 82%, most likely due to the more easily visible stem and lack of branches. When aggregating the results to 40 m square grid cells, at least one tree was detected in 77% of the grid cells which according to the field measurements contained one or more windthrown trees. (C) 2014 Elsevier B.V. All rights reserved.
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| 17. |
- Sandberg, Gustaf, 1982, et al.
(författare)
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L- and P-band backscatter intensity for biomass retrieval in hemiboreal forest
- 2011
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Ingår i: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257 .- 1879-0704. ; 115:11, s. 2874 - 2886
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Tidskriftsartikel (refereegranskat)abstract
- At present, the greatest source of uncertainty in the global carbon cycle is in the terrestrial ecosystems. In orderto reduce these uncertainties it is necessary to provide consistent and accurate global estimates of the worldforest biomass. One of the most promising methods for obtaining such estimates is through polarimetric SARbackscatter measurements at low frequencies. In this paper, the relation between polarimetric SAR backscatterat L- and P-bands and forest biomass is investigated using data acquired within the BioSAR-I campaign insouthern Sweden during 2007. Methods for estimating biomass on stand level using these data are developedand evaluated, and the results for the two frequency bands are compared. For L-band data, the best results wereobtained using HV-polarized backscatter only, giving estimation errors in terms of root mean square errors(RMSE) between 31% and 46% of the mean biomass for stands with biomass ranging from 10 to 290 t/ha, and an(adjusted) coefficient of determination (R2) between 0.4 and 0.6. For P-band data, the results are better thanfor L-band. Models using HV- or HH-polarized P-band backscatter give similar results, as does a modelincluding both HV and HH. The RMSEs were between 18 and 27%, and the R2 values were between 0.7 and 0.8.
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| 18. |
- Ulander, Lars, 1962, et al.
(författare)
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BIOSAR 2010 - A SAR campaign in support to the BIOMASS mission
- 2011
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Ingår i: Proceedings of IGARSS 2011 Symposium, Vancouver, Canada, 24-29 July, 2011. - 9781457710056 ; , s. 1528-1531, s. 1528-1531
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The ESA funded campaign BioSAR 2010 was carried out at the forestry test site Remningstorp in southern Sweden, in support to the BIOMASS satellite mission under study. Fully polarimetric SAR data were successfully acquired at L- and P-band using ONERA's multi-frequency system SETHI. In addition with other data types gathered, e.g. LiDAR and in-situ measurements, the compiled data set will be used for analyses and comparisons with biomass estimation results obtained at the same test site in the campaign BioSAR 2007, in which DLR's E-SAR made the SAR imaging. Detection of forest changes, robustness of biomass retrieval algorithms and long-term P-band coherence will be in focus as well as cross-validations between the two SAR sensors.
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| 19. |
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| 20. |
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