Optimizing gamma-ray spectrometers for UAV-borne surveys with geophysical applications.

Heavy duty unmanned aerial vehicles (UAVs) have made it possible to fly with large gamma-ray spectrometers that weigh several kilograms. Moreover, they can be purchased at an affordable price. These large UAV-borne gamma-ray detection systems are used to map the naturally occurring radionuclides 40K, 238U, 232Th. Such platforms have the advantage that they can be deployed over terrain that is difficult to access, while still maintaining a high spatial resolution. In contrast to UAV-borne radioactive pollution studies, the naturally occurring radionuclides have a much lower activity and therefore require longer integration time, slower flying speed or a larger detector, in order to effectively determine the spatial radionuclide distribution. Therefore, the question arises: what is the minimum practical detector size required to successfully map 40K, 238U and 232Th concentrations from UAV platforms. In this study an agricultural field has been mapped with three different scintillator-based gamma-ray spectrometers: a 2000 ml, 1000 ml, and 350 ml detector. They were mounted together on the same UAV. At a flying height of 20 m and a speed of 5.6 m s-1 the field was mapped. The various aerial measurements were compared to each other and to the ground-based measurements. The field had a low spatial variation in the 40K concentration (relative standard deviation (RSD) = 9%) and a larger variation for 238U and 232Th concentrations (RSD = 24% and 31% respectively). Radionuclide concentrations have been extracted from the survey data by Full Spectrum Analysis (FSA). Uncertainties and variances of the radionuclides have been determined by using two methods. Firstly, they are calculated directly from the FSA output and secondly they are extracted from a variogram. The latter incorporates spatial variation and was shown to provide a lower uncertainty. When using small detectors, the former approach could lead to the conclusion that the uncertainty is larger than the variance, while the variogram approach does capture the spatial variation. All three detectors were able to characterize the spatial distribution of the 232Th concentration. It is shown that the 232Th concentration is a good predictor of the sand and clay fraction of the topsoil in the field. By comparing the UAV-borne measurements to the ground-based measurements it is found that UAV-borne measurements at 20 m height are less sensitive to extreme values than ground-based measurements and they have the tendency to shift to the mean concentration of the area. The results of this study can be used to optimize the detector volume, survey height, and survey speed to maintain an acceptable accuracy for gamma-ray studies with small UAV-borne detectors.

Footprint and height corrections for UAV-borne gamma-ray spectrometry studies.

Advancements in the development of gamma-ray spectrometers (GRS) have led to small and lightweight spectrometers that can be used under unmanned aerial vehicles (UAVs). Airborne GRS measurements are used to determine radionuclide concentrations in the ground, among which the natural occurring radionuclides 40K, 238U, and 232Th. For successful applications of these GRS sensors, it is important that absolute values of concentrations can be measured. To extract these absolute radionuclide concentrations, airborne gamma-ray data has to be corrected for measurement height. However, the current analysis models are only valid for the height range of 50-250 m. The purpose of this study is to develop a procedure that correctly predicts the true radionuclide concentration in the ground when measuring in the UAV operating range of 0-40 m. An analytical model is developed to predict the radiation footprint as a function of height. This model is used as a tool to properly determine a source-detector geometry to be used in Monte-Carlo simulations of detector response at various elevations between 0 and 40 m. The analytical model predicts that the smallest achievable footprint at 10 m height lies between 22 and 91 m and between 40 and 140 m at 20 m height. By using Monte-Carlo simulations it is shown that the analytical model correctly predicts the reduction in full energy peak gamma-rays, but does not predict the Compton continuum of a spectrum as a function of height. Therefore, Monte-Carlo simulations should be used to predict the shape and intensity of gamma-ray spectra as a function of height. A finite set of Monte-Carlo simulations at intervals of 5 m were used for the analysis of GRS measurements at heights up to 35 m. The resulting radionuclide concentrations at every height agree with the radionuclide concentration measured on the ground.

Outcome after Hybrid Outflow Interventions for Chronic Limb-threatening Ischemia.

BACKGROUND AND AIMS: Because chronic limb-threatening ischemia (CLTI) is often associated with multilevel arterial disease, it usually requires revascularization at different sites of the limb vasculature. We aim to assess the outcome of the hybrid interventions including open surgical revascularization together with outflow segment percutaneous transluminal angioplasty (PTA) in patients with chronic limb-threatening ischemia. MATERIAL AND METHODS: This study included all hybrid outflow-PTA interventions (n = 80) on patients suffering from CLTI performed in Helsinki University Hospital between 2003 and 2015. Follow-up ended on 31 December 2019. Patient data were prospectively collected into our vascular registry and scrutinized retrospectively. Thirty-one patients (39%) suffered from rest pain (Rutherford category IV) and 49 patients (61%) had ischemic ulcers (Rutherford category V-VI). The most common open surgical procedure was femoral endarterectomy (n = 63, 79%) and the most common endovascular procedure was superficial femoral artery percutaneous transluminal angioplasty (n = 65, 81%). Mean follow-up time was 56 months (range: 4 days-183 months). RESULTS: Limb salvage was at 30 days-92%, at 1 year-91%, and at 5 and 10 years-86%. Survival and amputation-free survival were at 30 days-93% and 86%, at 1 year-80% and 76%, at 5 years-51% and 48%, and at 10 years-21% and 21%. Wound healing at 3, 6, and 12 months was 48%, 71%, and 87%. Freedom from target lesion revascularization was at 30 days-97%, at 1 year-88%, at 5 years-72%, and at 10 years-66%. CONCLUSION: Hybrid outflow revascularization is an important tool in the vascular surgeon's armamentarium for treatment of patients with multilevel arterial disease causing chronic limb-threatening ischemia.

Herd and environmental determinants of reproductive performance in Swedish dairy herds, 2001-2009.

This was a retrospective cohort study of Swedish dairy herds. Summary measures of production and reproductive performance, details of soil, moss mineral concentrations, and temperature and rainfall measurements at each herd location were available for the period September 2001 to August 2009. A Bayesian mixed-effects regression model including spatial and non-spatial heterogeneity terms was developed to quantify associations between hypothesised explanatory variables and mean herd breeding interval, defined as the difference between mean calving to last service interval and mean calving to first service interval for each fiscal year. Mean herd breeding intervals were shorter in herds with greater than 80% Swedish Red Cattle, herds with lower mean age at first calving, herds comprised of older cows and in larger herds. None of the soil composition or moss mineral concentration estimates were associated with mean herd breeding interval and the effect of temperature and rainfall on mean herd breeding interval was small. We conclude that environmental conditions (soil composition, moss mineral concentrations, environmental temperature and rainfall) had relatively minor effects on dairy herd reproductive performance in Sweden between 2001 and 2009.

Risk assessment of high concentrations of molybdenum in forage.

Molybdenum is toxic to ruminants when present in high levels in forage, causing physiological copper deficiency. A critical level for ruminants is 3-10 mg Mo kg-1 dry matter. The average Mo level varies considerably between different arable soils, depending mainly on soil parent material. This study investigated the possibility of using various existing sources of geospatial information (geophysical, biogeochemical and soil chemical) to develop a geography-based risk assessment system. Forage samples (n = 173) were collected in 2006-2007. Three types of national geoscientific datasets were tested: (1) SEPA topsoil, comprising data from arable land within the Swedish environmental monitoring programme; (2) SGU biogeochemical, containing data from aquatic plant root material collected in small streams; and (3) SGU geophysical, consisting of data from airborne gamma-ray scanning. The digital postcode area map was used for geocoding, with Mo concentrations in forage assigned to arable parts of the corresponding postcode area. By combining this with the three national geoscientific databases, it was possible to construct a risk map using fuzzy classification depicting High-risk, Intermediate-risk, Low-risk and Very-low-risk areas. The map was validated using 42 randomly selected samples. All samples but one with Mo > 3 mg kg-1 were found in postcode areas designated High risk. Thus, the risk map developed seems to be useful as a decision support system on where standard forage analyses need to be supplemented with Mo analyses.

In vivo imaging of Lyme arthritis in mice by [18F]fluorodeoxyglucose positron emission tomography/computed tomography.

OBJECTIVE: Lyme borreliosis (LB) is a tick-borne infectious disease caused by Borrelia burgdorferi spirochaetes, which are able to disseminate from the tick-bite site to distant organs. Mouse models are widely used to study LB and especially Lyme arthritis (LA), but only a few whole-animal in vivo imaging studies on the pathogenesis of B. burgdorferi infection in mice have been published so far. The existing imaging techniques have their drawbacks and, therefore, novel tools to complement the array of available LB imaging methodologies are needed. METHOD: The applicability of positron emission tomography combined with computed tomography (PET/CT) imaging was evaluated as a method to monitor LB and especially LA in the C3H/HeN mouse model infected with wild-type B. burgdorferi N40 bacteria. The imaging results were compared with the traditional LA analysis methods, such as tibiotarsal joint swelling and histopathological assessment of joint inflammation. RESULTS: PET/CT imaging provided high-resolution images with quantitative information on the spatial and temporal distribution of the [18F]fluorodeoxyglucose ([18F]FDG) tracer in B. burgdorferi-infected mice. The [18F]FDG accumulated in the affected joints and activated lymph nodes of infected mice, while the tracer signal could not be visualized in these organs in uninfected control animals. Importantly, in vivo PET/CT imaging data were in agreement with the histopathological scoring of inflammation of mouse joints. CONCLUSION: PET/CT imaging with [18F]FDG is a reliable method to longitudinally monitor the development and progression of B. burgdorferi infection-induced inflammation in vivo in mouse joints.

Long-term Results of Inframalleolar Bypass for Critical Limb Ischaemia.

INTRODUCTION: As the population ages and the incidence of diabetes increases, the expected number of patients with critical limb ischaemia (CLI) requiring distal revascularization will remain high or even increase. The aim of this study was to investigate the long-term results of inframalleolar bypass. MATERIAL AND METHODS: A total of 352 inframalleolar bypasses for CLI performed between 2002 and 2013 were included. Risk factors were evaluated and patency (both clinical and imaging based), leg salvage, survival, and amputation free survival (AFS) assessed. RESULTS: The median follow up was 30 months (mean 42 months, range 1-186 months). The median age of the study population was 73 years, and 67% of the patients were male. The incidence of diabetes was 69%. In the majority of cases (82%), the indication for bypass was an ulcer or gangrene, and the remaining 18% of the patients had rest pain. Primary, assisted primary, and secondary clinical patency was 71.2%, 76.5%, 81.0%, and 59.7%, 69.3%, and 70.7%, and 49.0%, 58.6%, and 68.4% at 1, 5, and 10 years, respectively. The last imaging based secondary patency at 1, 5, and 10 years was 79.3%, 68.1%, and 62.8%, respectively. The popliteal artery as the inflow artery (n = 194) was associated with superior primary (p = .013), assisted primary (p = .028), and secondary patency (p = .014) when compared with bypasses originating from the femoral artery (n = 158). The leg salvage rate at 1, 5, and 10 years was 78.6%, 72.0%, and 67.2%, respectively. Leg salvage was equal in patients with and without diabetes (p = .460). The respective survival and AFS rates at 1, 5, and 10 years were 70.3%, 37.4%, and 15.9%, and 58.4%, 29.8%, and 12.8%. CONCLUSION: Bypass to the foot arteries yielded excellent long-term patency, and good limb salvage can be achieved in both non-diabetic and diabetic patients.

Differential impact of bypass surgery and angioplasty on angiosome-targeted infrapopliteal revascularization.

OBJECTIVE: The aim of this study was to evaluate the impact of angiosome targeted revascularization according to the revascularization method. DESIGN: Retrospective observational study. MATERIALS AND METHODS: This study cohort comprised 744 consecutive patients who underwent infrapopliteal endovascular or surgical revascularization between January 2010 and July 2013. Differences in outcomes after bypass surgery and PTA were adjusted by estimating a propensity score, which was employed for one to one matching as well as adjusted analysis. RESULTS: Cox proportional hazards analysis showed that angiosome-targeted revascularization (HR 1.29, 95% CI 1.02-1.65), bypass surgery (HR 1.79, 95% CI 1.41-2.27), C-reactive protein ≤10 mg/dL (HR 1.42, 95% CI 1.11-1.81), and the number of affected angiosomes (HR 0.85, 95% CI 0.74-0.98) were independent predictors of improved wound healing. When adjusted for the number of affected angiosomes and C-reactive protein ≤10 mg/dL, angiosome-targeted bypass surgery was associated with a significantly higher rate of wound healing than non-angiosome-targeted angioplasty (HR 2.27, 95% CI 1.61-3.20). This was confirmed in propensity score adjusted analysis (HR 1.72, 95% CI 1.35-2.16). Among patients who underwent angiosome-targeted revascularization, the propensity score adjusted analysis showed that bypass surgery was associated with a significantly better rate of wound healing (HR 154, 95% CI 1.09-2.16) but similar limb salvage rates when compared with angioplasty (HR 0.79, 95% CI 0.44-1.43). CONCLUSION: Rates of wound healing and limb salvage in patients with critical limb ischemia (CLI) were significantly better after angiosome-targeted revascularization, bypass surgery achieving significantly better wound healing than angioplasty.

Cdc20 and securin overexpression predict short-term breast cancer survival.

BACKGROUND: Cdc20 is an essential component of cell division and responsible for anaphase initiation regulated by securin degradation. Cdc20 function is strongly regulated by the spindle assembly checkpoint to ensure the timely separation of sister chromatids and integrity of the genome. We present the first results on Cdc20 in a large clinical breast cancer material. METHODS: The study was based on 445 breast cancer patients with up to 20 years of follow-up (mean 10.0 years). DNA content was determined by image cytometry on cell imprints, and Cdc20 and securin immunohistochemistry on tissue microarrays of breast cancer tissue. RESULTS: In our results, high Cdc20 and securin expression was associated with aneuploid DNA content. In prognostic analyses, high Cdc20 immunoexpression alone and in combination with high securin immunoexpression indicated aggressive course of disease and up to 6.8-fold (P<0.001) risk of breast cancer death. Particularly, high Cdc20 and securin immunoexpression identified a patient subgroup with extremely short, on average 2.4 years, breast cancer survival and triple-negative breast cancer (TNBC) subtype. CONCLUSIONS: We report for the first time the association of high Cdc20 and securin immunoexpression with extremely poor outcome of breast cancer patients. Our experience indicates that Cdc20 and securin are promising candidates for clinical applications in breast cancer prognostication, especially in the challenging prognostic decisions of TNBC.

Casein hydrolysate diet controls intestinal T cell activation, free radical production and microbial colonisation in NOD mice.

AIMS/HYPOTHESIS: Dietary and microbial factors and the gut immune system are important in autoimmune diabetes. We evaluated inflammatory activity in the whole gut in prediabetic NOD mice using ex vivo imaging of reactive oxygen and nitrogen species (RONS), and correlated this with the above-mentioned factors. METHODS: NOD mice were fed a normal diet or an anti-diabetogenic casein hydrolysate (CH) diet. RONS activity was detected by chemiluminescence imaging of the whole gut. Proinflammatory and T cell cytokines were studied in the gut and islets, and dietary effects on gut microbiota and short-chain fatty acids were determined. RESULTS: Prediabetic NOD mice displayed high RONS activity in the epithelial cells of the distal small intestine, in conjunction with a proinflammatory cytokine profile. RONS production was effectively reduced by the CH diet, which also controlled (1) the expression of proinflammatory cytokines and colonisation-dependent RegIIIγ (also known as Reg3g) in ileum; (2) intestinal T cell activation; and (3) islet cytokines. The CH diet diminished microbial colonisation, increased the Bacteroidetes:Firmicutes ratio, and reduced lactic acid and butyric acid production in the gut. CONCLUSIONS/INTERPRETATION: Epithelial RONS production and proinflammatory T cell activation appears in the ileum of NOD mice after weaning to normal laboratory chow, but not after weaning to an anti-diabetogenic CH diet. Our data suggest a link between dietary factors, microbial colonisation and mucosal immune activation in NOD mice.

The quality of the outdoor environment influences childrens health -- a cross-sectional study of preschools.

AIM: To test how the quality of the outdoor environment of child day care centres (DCCs) influences children's health. METHODS: The environment was assessed using the Outdoor Play Environmental Categories (OPEC) tool, time spent outdoors and physical activity as measured by pedometer. 172/253 (68%) of children aged 3.0-5.9 from nine DCCs participated in Southern Sweden. Health data collected were body mass index, waist circumference, saliva cortisol, length of night sleep during study, and symptoms and well-being which were scored (1-week diary - 121 parent responders). Also, parent-rated well-being and health of their child were scored (questionnaire, 132 parent responders). MANOVA, ANOVA and principal component analyses were performed to identify impacts of the outdoor environment on health. RESULTS: High-quality outdoor environment at DCCs is associated with several health aspects in children such as leaner body, longer night sleep, better well-being and higher mid-morning saliva cortisol levels. CONCLUSION: The quality of the outdoor environment at DCCs influenced the health and well-being of preschool children and should be given more attention among health care professionals and community planners.

Angiosome theory: fact or fiction?

The angiosome concept delineates the human body into three-dimensional blocks of tissue fed by specific arterial and venous sources named "angiosomes." Adjacent angiosomes are connected by a vast compensatory collateral web, or "choke vessels." This concept may provide new information applicable to improving targeted revascularization of ischemic tissue lesions. A few dedicated studies available seem to favor this strategy, as encouraging ulcer healing and limb preservation are reported in connection with both bypass and endovascular techniques based on these principles. The theory on the angiosome model of revascularization (AMV) may help the clinician to better refine vessel selection, vascular access, and specific strategies in the revascularization of critically ischemic legs with tissue lesions. Specific applications of angiosome-guided revascularization were recently suggested for patients with diabetes or renal insufficiency, with ischemic tissue lesions of the lower limb, and extended large- and medium-size collateral network decay. For these cases, the concept may allow deliberate arterial reconstruction following individual wound topographies in specific ischemic areas, although deprived from "rescue-vessel" supply. The AMV theory may contribute to a shift in common reperfusion options. However, the data available is suggestive and does not provide strong evidence as factors such as case mix and the severity of ischemia are unsatisfactorily controlled. At present, the evidence is scarce as to the effect of the severity of the arterial disease. In all comparisons, the groups treated are likely to be dissimilar and mismatched. The angiosome concept is postulated to be valid especially in diabetics, whose ischemic lesions tend to heal worse than those of non-diabetics.

End-stage renal disease and critical limb ischemia: a deadly combination?

OBJECTIVES: This study was planned to evaluate the prognostic impact of end-stage renal disease (ESRD) in patients with critical leg ischemia (CLI) undergoing infrainguinal revascularization. MATERIALS AND METHODS: 1425 patients who underwent infrainguinal revascularization for CLI were the subjects of the present analysis. Ninety-five patients had ESRD (eGFR < 15 ml/min/m²), and of them 66 (70%) underwent percutaneous transluminal angioplasty and 29 (30%) underwent bypass surgery. RESULTS: ESRD patients had significantly lower overall survival (at 3-year, 27.1% vs. 59.7%, p < 0.0001), leg salvage (at 3-year, 57.7% vs. 83.0%, p < 0.0001), and amputation free survival (at 3-year, 16.2% vs. 52.9%, p < 0.0001) than patients with no or less severe renal failure. The difference in survival was even greater between 86 one-to-one propensity matched pairs (at 3-year, 23.1% vs. 67.3%, p < 0.0001). ESRD was an independent predictor of all-cause mortality (RR 2.46, 95%CI 1.85-3.26). Logistic regression showed that age ≥ 75 years was the only independent predictor of 1-year all-cause mortality (OR 4.92, 95%CI 1.32-18.36). Classification and regression tree analysis showed that age ≥ 75 years and, among younger patients, bypass surgery for leg ulcer and gangrene were associated with significantly higher 1-year mortality CONCLUSIONS: Lower limb revascularization in patients with CLI and end-stage renal failure is associated with favourable leg salvage. However, these patients have a very poor survival and this may jeopardize any attempt of revascularization. Further studies are needed to identify ESRD patients with acceptable life expectancy and who may benefit from lower limb revascularization.

The role of chronic kidney disease as a predictor of outcome after revascularisation of the ulcerated diabetic foot.

AIMS/HYPOTHESIS: The aim of the study was to stratify the risk of diabetic patients with leg ulcer or gangrene undergoing infrainguinal revascularisation for critical limb ischaemia. METHODS: The study cohort included 732 revascularisation procedures performed in 597 diabetic patients with ulcer or gangrene. Logistic regression and CART analysis were used for identification of predictors of 1-year outcome. RESULTS: Logistic regression showed that chronic kidney disease (CKD) class (OR 1.38, 95% CI 1.16, 1.65) was an independent predictor of 1-year leg salvage (area under the receiver operating characteristic [ROC] curve 0.60, 95% CI 0.54, 0.65). The terminal nodes of the CART for 1-year leg salvage were CKD classes 4-5, the level (infrapopliteal vs femoropopliteal revascularisation), type of revascularisation (bypass surgery vs percutaneous transluminal angioplasty) and gangrene (area under the ROC curve 0.62, 95% CI 0.57, 0.68). Logistic regression showed that pulmonary disease (OR 1.76, 95% CI 1.11, 2.78), CKD class (OR 1.43, 95% CI 1.24, 1.65), foot gangrene (OR 1.76, 95% CI 1.21, 2.60) and patient age (OR 1.02, 95% CI 1.01, 1.04) were independent predictors of 1-year amputation-free survival (area under the ROC curve 0.65, 95% CI 0.60, 0.69). The terminal nodes of the CART for 1-year amputation-free survival were CKD classes 3-5, patient's age of ≥ 75 years and foot gangrene (area under the ROC curve 0.64, 95% CI 0.60, 0.68). CONCLUSIONS/INTERPRETATION: CKD is a formidable risk factor for poor intermediate outcome after infrainguinal revascularisation in diabetic patients with foot ulcer or gangrene. CART analysis indicates that foot gangrene is also a significant risk factor for adverse outcome.

Infrainguinal percutaneous transluminal angioplasty or bypass surgery in patients aged 80 years and older with critical leg ischaemia.

BACKGROUND: Infrainguinal revascularization for critical leg ischaemia (CLI) in patients aged 80 years and over is associated with increased operative risk. The aim was to compare the results of percutaneous transluminal angioplasty (PTA) and bypass surgery in these patients. METHODS: Some 584 consecutive patients aged at least 80 years treated with either PTA (277) or bypass surgery (307) for CLI between 2000 and 2007 were included in this study. RESULTS: After 2 years PTA achieved better results than bypass surgery (leg salvage: 85.4 versus 78.7 per cent, P = 0.039; survival: 57.7 versus 52.3 per cent, P = 0.014; amputation-free survival (AFS): 53.0 versus 44.9 per cent, P = 0.005). Cox regression analysis showed that increased age (relative risk (RR) 1.05, 95 per cent confidence interval 1.02 to 1.08), decreased estimated glomerular filtration rate (RR 0.99, 0.99 to 1.00), diabetes (RR 1.30, 1.04 to 1.62), coronary artery disease (RR 1.36, 1.05 to 1.75) and bypass surgery (RR 1.55, 1.24 to 1.93) were associated with decreased AFS. In 95 propensity score-matched pairs, leg salvage at 2 years (88 versus 75 per cent; P = 0.010) and AFS (53 versus 45 per cent; P = 0.033) were significantly better after PTA. Classification and regression tree analysis suggested that PTA was associated with better 1-year AFS, especially in patients with coronary artery disease (63.8 versus 48.9 per cent; P = 0.008). CONCLUSION: When feasible, a strategy of PTA first appears to achieve better results than infrainguinal bypass surgery in patients aged 80 years and older.

Femoropopliteal balloon angioplasty vs. bypass surgery for CLI: a propensity score analysis.

OBJECTIVES: To compare the outcomes of femoropopliteal percutaneous transluminal angioplasty (PTA) and bypass surgery for critical limb ischaemia (CLI). DESIGN: The study is retrospective in nature. MATERIALS AND METHODS: This study included 858 consecutive patients, who underwent femoropopliteal revascularisation for CLI at Helsinki University Central Hospital during 2000-2007. As many as 517 patients (60%) underwent PTA and 341 (40%) bypass surgery. Propensity score analysis was used for risk adjustment in multivariable analysis and for one-to-one matching. RESULTS: In the overall series, PTA had poorer long-term results than bypass (5-year leg salvage, 78.2% vs. 91.8%, p < 0.0001; survival 49.2% vs. 57.1%, p = 0.048; amputation-free survival, 42.0% vs. 53.7%, p = 0.003; freedom from surgical re-intervention 86.2% vs. 94.3%, p < 0.0001). When treatment method was adjusted for propensity score as well as in the propensity score-matched pairs, leg salvage and freedom from surgical re-intervention were worse after PTA than after bypass (among the 241 propensity score-matched pairs, 74.3% vs. 88.2%, p = 0.031, and 86.1% vs. 89.8%, p = 0.025, respectively). Differences in survival, amputation-free survival and freedom from any re-intervention were not observed. CONCLUSIONS: In CLI patients, femoropopliteal PTA seems to be associated with poorer long-term leg salvage and freedom from surgical re-intervention than bypass surgery. However, the treatment method did not affect long-term amputation-free survival.

High leg salvage rate after infrainguinal bypass surgery for ischemic tissue loss (Fontaine IV) is compromised by the short life expectancy.

BACKGROUND AND AIMS: Most studies analysing the prognosis of infrainguinal bypass surgery (IBS) in patients with critical leg ischemia (CLI) have combined the outcome of patients with rest pain and tissue loss. The aim of the present study was to evaluate amputation-free survival (AFS) after IBS in patients with the most advanced form of peripheral arterial disease, CLI with tissue loss (Fontaine IV), and to analyse the risk factors for an adverse outcome. PATIENTS AND METHODS: 636 patients with CLI and tissue loss who underwent unilateral IBS between January 2000 and December 2006 at our institution were included in this retrospective study. RESULTS: At one year, the leg salvage, survival and amputation-free survival rates were 83%, 71% and 55%, respectively, and at five years 76%, 38% and 30%, respectively. In univariate analysis, diabetes was associated with decreased AFS. In multivariate analysis, age, coronary artery disease, chronic pulmonary disease, gangrene and renal insufficiency were independent risk factors for decreased AFS. CONCLUSION: Infrainguinal bypass grafting results in a high rate of leg salvage. Amputation-free survival was low during the follow-up due to the high mortality of patients with CLI and tissue loss. Several co-morbidities of the CLI patients were associated with decreased amputation-free survival.

Outdoor environmental assessment of attention promoting settings for preschool children.

The restorative potential of green outdoor environments for children in preschool settings was investigated by measuring the attention of children playing in settings with different environmental features. Eleven preschools with outdoor environments typical for the Stockholm area were assessed using the outdoor play environment categories (OPEC) and the fraction of visible sky from play structures (sky view factor), and 198 children, aged 4.5-6.5 years, were rated by the staff for inattentive, hyperactive and impulsive behaviors with the ECADDES tool. Children playing in large and integrated outdoor areas containing large areas of trees, shrubbery and a hilly terrain showed less often behaviors of inattention (p<.05). The choice of tool for assessment of attention is discussed in relation to outdoor stay and play characteristics in Swedish preschool settings. The results indicate that the restorative potential of green outdoor environments applies also to preschool children and that environmental assessment tools as OPEC can be useful when to locate and develop health-promoting land adjacent to preschools.

Healing of ischaemic tissue lesions after infrainguinal bypass surgery for critical leg ischaemia.

OBJECTIVE: To evaluate healing time of ischaemic tissue lesions, limb salvage and survival in patients suffering from critical limb ischaemia (CLI) with tissue loss. DESIGN: Prospective single centre cohort study. MATERIAL AND METHODS: Consecutive patients with CLI and tissue loss (Fontaine IV) (148 patients, 150 limbs) were followed prospectively for 1 year after infrainguinal bypass. Healing time of tissue lesions, graft patency, limb salvage, survival rates and the overall need for any type of surgical and endovascular procedure were analysed. Patient comorbidities were assessed by uni- and multivariate analysis to determine risk factors for adverse outcome. RESULTS: Complete tissue healing, including healing of ischaemic tissue lesions and surgical wounds, at 6 and 12 months after the infrainguinal bypass were respectively 40% and 75%. The median time to complete tissue healing was 190 days. Diabetes was the only significant risk factor which delayed tissue healing. Overall patency, limb salvage, survival and amputation-free survival rates were respectively at 12 months 80%, 81%, 73% and 63%. The clinically important endpoint amputation-free survival with completely healed wounds was attained in 50% of patients at 1 year. CONCLUSION: Complete healing of ischemic tissue lesions is slow even after a successful infrainguinal bypass.

Estimated glomerular filtration rate (eGFR) as a predictor of outcome after infrainguinal bypass in patients with critical limb ischemia.

OBJECTIVES: Renal insufficiency is a risk factor for poor outcome after infrainguinal bypass in patients with critical limb ischemia (CLI). Estimated glomerular filtration rate (eGFR) takes age, gender and body size into account and therefore represents actual renal function more accurately than serum creatinine level alone. The aim of this study was to determine the impact of different stages of renal insufficiency on outcome and to assess the prognostic significance of eGFR in patients with CLI. MATERIAL AND METHODS: 603 patients with CLI who underwent infrainguinal bypass between January 2002 and December 2005 at our institution were included in this retrospective study. We estimated GFR using the Modification of Diet in Renal Disease (MDRD) Study equation. Survival, leg salvage and amputation-free survival were calculated using Kaplan-Meier method. Cox regression analysis was performed to calculate hazard ratios for different outcome variables. RESULTS: Adjusted hazard ratio (HR) of mortality, limb loss and limb loss and/or death for eGFR < 30 ml/min/1.73 m(2) versus serum creatinine > 200 micromol/l was 4.0 (95% CI 2.22-7.39) vs 3.5 (95% CI 1.82-6.84), 6.5 (95% CI 2.71-15.59) vs 6.2 (95% CI 2.47-15.56) and 4.0 (95% CI 2.40-6.63) vs 3.6 (95% CI 2.03-6.25), respectively. CONCLUSION: Estimated GFR is better predictor of survival, leg salvage and amputation-free survival than serum creatinine alone. eGFR < 30 ml/min/1.73 m(2) is independent risk factor for all three outcome endpoints.