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David R Anderson

Publications and source records attributed to David R Anderson.

At least 19 recordsLinked to original sources
PubMed2006

PCDD/F and "Dioxin-like" PCB emissions from iron ore sintering plants in the UK.

Investigations have been carried out at the three Corus UK sinter plants over the period 2002-2004 to characterise the emissions of both 2,3,7,8-PCDD/Fs and WHO-12 PCBs, to estimate annual mass releases of these organic micro-pollutants using the I-TEF and WHO-TEF schemes, and to investigate the formation of PCBs in the iron ore sintering process. Results showed that the sintering of iron ore produces a characteristic WHO-12 PCB and PCDD/F congener pattern that is substantially the same for all UK sinter plants. With regard to WHO-12 PCBs, the most abundant congeners were typically PCBs 118 (6-9 ngNm(-3)), 105 (2-4 ngNm(-3)) and 77 (2-3 ngNm(-3)). All other WHO-12 PCBs were also detected at concentrations around 1 ngNm(-3). All sinter plants investigated exhibited very similar TEQ concentrations. WHO-12 PCB emissions were in the range 0.042-0.111 ngWHO-TEQNm(-3), whereas PCDD/F emissions ranged from 0.39 to 1.62 ngWHO-TEQNm(-3). PCDF congeners were the main contributors to the overall TEQ in sintering emissions (ca. 85%). Amongst WHO-12 PCBs, PCB 126 was the only noteworthy contributor to total TEQ (ca. 5-7%), a similar contribution to that from PCDDs. Based on the measurements that Corus UK has undertaken at these three sinter plants, annual mass releases of WHO-12 PCBs and PCDD/Fs have been calculated. For UK sinter plants, a total mass release of 29.5 g WHO-TEQ per annum [WHO-12 PCBs+PCDD/Fs] has been estimated, representing 9% of the total PCDD/F emissions to the UK atmosphere. Measurements were also carried out at a UK sinter plant to determine the windleg emission profile of WHO-12 PCBs. Results showed that WHO-12 PCBs were formed in the same regions of the sinter strand as 2,3,7,8-PCDD/Fs, indicating that there was a strong correlation between the formation of WHO-12 PCBs and PCDD/Fs in the iron ore sintering process.

Air Pollutants↗
PubMed2006

An evaluation of D-dimer in the diagnosis of pulmonary embolism: a randomized trial.

BACKGROUND: It may be safe to omit additional diagnostic testing in selected patients with suspected pulmonary embolism (PE) who have a negative D-dimer test, but this approach has never been evaluated in a randomized, controlled trial. OBJECTIVE: To determine if additional diagnostic testing can be safely withheld in patients with suspected PE who have negative erythrocyte agglutination D-dimer test results. DESIGN: Randomized comparisons in 2 subgroups of a prospective multicenter study. SETTING: 7 university hospitals. PATIENTS: 1126 outpatients or inpatients with suspected PE; of these, 456 patients with negative erythrocyte agglutination D-dimer test results were randomly assigned to the intervention groups. Patients were classified into 2 clinical probability groups: those with a low clinical probability of PE (low-probability group) and those with a moderate or high clinical probability of PE, a nondiagnostic ventilation-perfusion lung scan, and no evidence of proximal deep venous thrombosis on bilateral ultrasonography (moderate- or high-probability group). INTERVENTIONS: The experimental intervention for both probability groups was no further diagnostic testing for PE. The control intervention for the low-probability group was a ventilation-perfusion lung scan followed by ultrasonography of the proximal deep veins of the legs on the same day. If the lung scan was nondiagnostic, ultrasonography of the legs was repeated 7 and 14 days later. The control intervention for the moderate- or high-probability group was ultrasonography of the proximal deep veins of the legs after 7 and 14 days. In the control and experimental groups, anticoagulation was withheld or withdrawn if PE was not diagnosed. MEASUREMENTS: Symptomatic venous thromboembolism (VTE) during 6 months of follow-up. RESULTS: Prevalence of VTE was 15.2% in the 1126 enrolled patients. In the low-probability group, VTE occurred during follow-up in 0 of 182 patients who had no additional diagnostic testing and in 1 of 185 patients who had additional testing (difference, -0.5 percentage point [95% CI, -3.0 to 1.6 percentage points]). In the moderate- or high-probability group, VTE occurred during follow-up in 1 of 41 patients who had no additional diagnostic testing and in 0 of 41 patients who had additional testing (difference, 2.4 percentage points [CI, -6.4 to 12.6 percentage points]). LIMITATIONS: The authors could not enroll 2000 patients as originally planned; 3 randomly assigned patients did not receive the allocated intervention, and 7 received inadequate follow-up. Personnel who performed follow-up evaluations were not blinded to the results of diagnostic testing at enrollment or to allocation group assignments. CONCLUSION: In patients with a low probability of PE who have negative D-dimer results, additional diagnostic testing can be withheld without increasing the frequency of VTE during follow-up. Low clinical probability and negative D-dimer results occur in 50% of outpatients and in 20% of inpatients with suspected PE.

Fibrin Fibrinogen Degradation Products↗
PubMed2005

A randomized trial comparing 2 low-molecular-weight heparins for the outpatient treatment of deep vein thrombosis and pulmonary embolism.

BACKGROUND: Low-molecular-weight heparins (LMWHs) are now standard therapy for the treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE). No published trials have compared LMWHs, and few studies have examined outpatient therapy for PE. Only tinzaparin sodium has demonstrated superiority to unfractionated heparin in a clinical trial. METHODS: We compared 2 LMWH products, tinzaparin and dalteparin sodium, for the treatment of acute DVT and PE in a randomized, controlled clinical trial of consecutive outpatients presenting to a venous thromboembolism service at 4 tertiary-care hospitals. Patients were treated with subcutaneous tinzaparin sodium, 175 IU/kg every 24 hours, or subcutaneous dalteparin sodium, 200 IU/kg every 24 hours, for at least 5 days. Warfarin sodium therapy was started simultaneously and continued for 90 days. The primary end point was efficacy (recurrence of venous thromboembolism); safety (bleeding) was a composite end point. RESULTS: Two hundred fifty-four patients received tinzaparin (39 with PE and 215 with DVT) and 251 received dalteparin (51 with PE and 200 with DVT). Most patients had an active malignancy or idiopathic DVT/PE. The outcome events occurred in 11 (4.4%; 95% confidence interval [CI], 2.2%-7.7%) and 15 patients (5.9%; 95% CI, 3.3%-9.5%) in the dalteparin and tinzaparin groups, respectively, including 9 and 10 recurrences, respectively, and 2 and 5 major hemorrhages, respectively (P = .44). The 95% CI on the difference of -1.5% was -5.3% to 2.4%. CONCLUSIONS: Tinzaparin and dalteparin are safe and effective for the outpatient treatment of DVT or PE. Our finding of no differences between the LMWHs based on major clinical end points means that practical issues can be the deciding factor on which drug to use.

Acute Disease↗
PubMed2005

Influence of warfarin on symptoms of fatigue: findings of a randomized trial.

BACKGROUND: Some patients develop fatigue while taking warfarin, but causality is uncertain. OBJECTIVE: To assess whether warfarin use is associated with fatigue. METHODS: This investigation was a substudy of a randomized double-blind trial in 13 outpatient thromboembolism clinics. Subjects who had received one month of open-label warfarin therapy for venous thromboembolism due to a transient risk factor were randomly assigned to receive warfarin or placebo for 2 months and followed for another 9 months after stopping the study drug. Fatigue was measured using a Likert scale, and change of fatigue was measured by the patient's global rating. RESULTS: In 87 subjects, the overall ratings of fatigue were 0.1 unit lower (95% CI 0.6 units lower to 0.4 units higher) while taking warfarin. Global rating for change in fatigue intensity showed no increase of fatigue with warfarin use. CONCLUSIONS: The short-term use of warfarin was not associated with symptoms of fatigue.

Analysis of Variance↗
PubMed2005

Randomized placebo-controlled study of low-dose warfarin for the prevention of central venous catheter-associated thrombosis in patients with cancer.

PURPOSE: In this multicenter, randomized, placebo-controlled clinical trial, we studied whether warfarin 1 mg daily reduces the incidence of symptomatic central venous catheter (CVC) -associated thrombosis in patients with cancer. PATIENTS AND METHODS: Two hundred fifty-five patients with cancer who required a CVC for at least 7 days were randomly assigned to receive warfarin 1 mg or placebo. RESULTS: There were 11 (4.3%) symptomatic CVC-associated thromboses among 255 patients, with no difference in the incidence of symptomatic CVC-associated thrombosis between patients taking warfarin 1 mg daily (six of 130 patients; 4.6%) and patients taking placebo (five of 125 patients; 4.0%; hazard ratio, 1.20; 95% CI, 0.37 to 3.94). Warfarin had no effect on CVC life span (84 days v 63 days in control and warfarin groups, respectively; 95% confidence limit, -16 to 55 days; P = .09), and it did not affect the number of premature CVC removals (23.2% v 25.4% in control and warfarin groups, respectively; 95% confidence limit of difference -8.34 to 12.71; P = .68) or the frequency of major bleeding episodes (2% v 0% in control and warfarin groups, respectively; P = .5, Fisher's exact test). CONCLUSION: Symptomatic CVC-associated thrombosis in patients with cancer, although significant, is less common than previously reported. In this study, the administration of warfarin 1 mg daily did not reduce the incidence of symptomatic CVC-associated thrombosis in patients with cancer. However, the low rate of symptomatic CVC-associated thrombosis means that a much larger trial is required to address this issue definitively.

Adolescent↗
PubMed2005

Use of spiral computed tomography contrast angiography and ultrasonography to exclude the diagnosis of pulmonary embolism in the emergency department.

Spiral computed tomography (CT) contrast angiography is a promising imaging modality for the diagnosis of pulmonary embolism but the negative predictive value of this test remains controversial. We performed a multi-center prospective cohort study to determine the safety of relying on a negative spiral CT contrast angiography scan to exclude pulmonary embolism. Patients presenting to the Emergency Departments of three tertiary care institutions with clinically suspected pulmonary embolism were potentially eligible for the study. Patients underwent a clinical evaluation to categorize pretest probability into low, moderate, and high categories, and had D-dimer testing performed. Patients at low pretest probability with normal D-dimer were considered to have pulmonary embolism excluded. The remaining patients underwent spiral CT contrast angiography scan of the pulmonary arterial circulation and bilateral venous ultrasound of the proximal leg veins. Patients who were confirmed to have pulmonary embolism or deep vein thrombosis were treated with anticoagulant therapy. Patients in whom the diagnosis of pulmonary embolism was excluded did not receive anticoagulant therapy and were followed for a 3-month period for the development of venous thromboembolic complications. Eight hundred fifty-eight (858) patients were enrolled in this study. Three-hundred sixty-nine (369) patients had low pretest probability and negative D-dimer results and no further diagnostic tests were performed. None of these patients subsequently developed venous thromboembolic complications (0%, 95% confidence interval [CI] 0% to 1.0%). The remaining 489 were referred for spiral CT contrast angiography scan and ultrasound. Sixty-seven patients were confirmed to have pulmonary embolism and an additional 15 patients with negative CT scans had proximal deep vein thrombosis (DVT) on ultrasound for a total prevalence of venous thromboembolism of 82/489 (16.8%). Two of 409 patients who had pulmonary embolism excluded in the initial evaluation phase developed proximal venous thromboembolism (0.5%; 95% CI 0% to 1.8%) in the 3-month follow-up period. These findings suggest that the combination of a negative spiral CT contrast angiography scan and normal venous ultrasound imaging safely excludes the diagnosis of pulmonary embolism in the Emergency Department setting.

Contrast Media↗
PubMed2005

Population-based evaluation of the management of antithrombotic therapy for atrial fibrillation.

BACKGROUND: Oral anticoagulation is an effective therapy for the prevention of cardioembolic complications in patients with atrial fibrillation. However, previous practice reviews have indicated that oral anticoagulants are often underused in this setting. Most of those reports have focused on reviews of hospitalized and institutionalized patients, or small geographical areas. OBJECTIVES: To determine the use of antithrombotic therapy for the treatment of atrial fibrillation in Nova Scotia and to survey the knowledge of antithrombotic therapy for atrial fibrillation among a concurrent cohort of primary care and specialist physicians involved in the management of patients with atrial fibrillation. PATIENTS AND METHODS: Patients with atrial fibrillation were identified through outpatient electrocardiography clinics held throughout Nova Scotia. Following consent of the primary care physicians, patients were contacted and completed a survey about their current management. Family physicians and specialists in Nova Scotia were also surveyed about the management of atrial fibrillation with antithrombotic therapy through the receipt of one of four case scenarios. RESULTS: Four hundred twenty-five patients participated in the cross-sectional survey. The mean patient age was 70.6 years, 255 (60%) were male and 398 (93.6%) had at least one risk factor for stroke in addition to atrial fibrillation. Two hundred ninety-four patients (69.2%) were receiving oral anticoagulants either alone (61.9%) or in combination with acetylsalicylic acid (ASA) (7.3%). An additional 85 patients (20%) received ASA alone. There was no difference in the rates of prescription of oral anticoagulants between elderly patients (75 years of age and older) and those younger than 75 years (71.7% versus 67.3%, 95% CI -13.1% to 4.5%; P=0.34). Overall, 72.0% of patients were receiving antithrombotic therapy in accordance with the 2001 guidelines of the American College of Chest Physicians, with no difference in the rates between individuals younger than 75 years (72.2%) and those over 75 years of age (71.7%) (absolute difference -0.5%, 95% CI -9.2% to 8.1%). Physician responses to case scenarios indicated that knowledge was high among both general practitioners and specialists regarding the appropriate use of oral anticoagulants for the prevention of thrombotic complications associated with atrial fibrillation. CONCLUSIONS: The appropriate use of oral antithrombotic therapy for the prevention of thrombotic complications of atrial fibrillation occurs in approximately 72% of patients studied in Nova Scotia, and physician knowledge about this indication is high. There was no bias against prescribing oral anticoagulants to elderly patients. The findings suggest that with time, education and evidence have positively impacted the use of antithrombotic therapy in these patients.

Administration, Oral↗
PubMed2004

Venous protocols, techniques, and interpretations of the upper and lower extremities.

Deep venous thrombosis and pulmonary embolism are common problems and frequently included in the differential diagnosis of patients presenting to the emergency department and in the acute care setting. Clinical signs and symptoms of these entities are nonspecific and it is important to perform objective testing to confirm the diagnosis and initiate proper therapy. Compression ultrasonography is the diagnostic procedure of choice for the investigation of patients with suspected deep venous thrombosis. This article reviews the clinical indications, diagnostic techniques, and interpretation of compression ultrasound to assess deep venous thrombosis in the upper and lower extremities and to evaluate the role of compression ultrasonography in the assessment of patients with suspected pulmonary embolism.

Diagnostic Imaging↗
PubMed2004

Development and validation of a method for analysis of "dioxin-like" PCBs in environmental samples from the steel industry.

A method, previously used for determination of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), has been modified for quantitative analysis of "dioxin-like" polychlorobiphenyls (PCBs) in environmental samples from the steel industry. The existing sample clean-up procedure, involving liquid chromatography on multi-layered silica and Florisil columns, has been extended to include a third chromatography stage on a basic alumina stationary phase. The additional clean-up stage is required for PCB analysis in order to eliminate interferences from relatively large concentrations of saturated cyclic and aliphatic hydrocarbons. Samples were analysed for WHO-12 congeners using high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) and standard solutions of the method US EPA 1668A. Replicate analysis of method blanks revealed background contamination for PCBs 118, 105 and 77, which are generally abundant in ambient air. These contaminants were taken into account using a subtraction method. The entire procedure was validated by replicate analysis (N = 3) of a certified reference sediment. The RSD for each WHO-12 congener was below 15%, 13C12-labelled PCB internal standard recoveries were in the range 70-95%. A waste dust sample collected in the electrostatic precipitator of a UK sinter plant was analysed for determination of PCDD/Fs and WHO-12 PCBs and exhibited a PCDD/F I-TEQ of 148.5 +/- 21.2 ngkg(-1) and a WHO-TEQ of 7.2 +/- 1.5 ngkg(-1). WHO-12 congeners contributed only 4.6% to the overall TEQ and PCB 126 was the major congener contributing to the WHO-TEQ (96%). The contribution to the overall TEQ of the waste dust sample was mainly attributed to PCDF followed by PCDD, which accounted for 86.6% and 8.7% to the overall TEQ, respectively.

Air Pollution↗
PubMed2003

Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis.

BACKGROUND: Several diagnostic strategies using ultrasound imaging, measurement of D-dimer, and assessment of clinical probability of disease have proved safe in patients with suspected deep-vein thrombosis, but they have not been compared in randomized trials. METHODS: Outpatients presenting with suspected lower-extremity deep-vein thrombosis were potentially eligible. Using a clinical model, physicians evaluated the patients and categorized them as likely or unlikely to have deep-vein thrombosis. The patients were then randomly assigned to undergo ultrasound imaging alone (control group) or to undergo D-dimer testing (D-dimer group) followed by ultrasound imaging unless the D-dimer test was negative and the patient was considered clinically unlikely to have deep-vein thrombosis, in which case ultrasound imaging was not performed. RESULTS: Five hundred thirty patients were randomly assigned to the control group, and 566 to the D-dimer group. The overall prevalence of deep-vein thrombosis or pulmonary embolism was 15.7 percent. Among patients for whom deep-vein thrombosis had been ruled out by the initial diagnostic strategy, there were two confirmed venous thromboembolic events in the D-dimer group (0.4 percent; 95 percent confidence interval, 0.05 to 1.5 percent) and six events in the control group (1.4 percent; 95 percent confidence interval, 0.5 to 2.9 percent; P=0.16) during three months of follow-up. The use of D-dimer testing resulted in a significant reduction in the use of ultrasonography, from a mean of 1.34 tests per patient in the control group to 0.78 in the D-dimer group (P=0.008). Two hundred eighteen patients (39 percent) in the D-dimer group did not require ultrasound imaging. CONCLUSIONS: Deep-vein thrombosis can be ruled out in a patient who is judged clinically unlikely to have deep-vein thrombosis and who has a negative D-dimer test. Ultrasound testing can be safely omitted in such patients.

Agglutination Tests↗
PubMed2003

Comparing the quality of oral anticoagulant management by anticoagulation clinics and by family physicians: a randomized controlled trial.

BACKGROUND: There is growing evidence that better outcomes are achieved when anticoagulation is managed by anticoagulation clinics rather than by family physicians. We carried out a randomized controlled trial to evaluate these 2 models of anticoagulant care. METHODS: We randomly allocated patients who were expected to require warfarin sodium for 3 months either to anticoagulation clinics located in 3 Canadian tertiary hospitals or to their family physician practices. We evaluated the quality of oral anticoagulant management by comparing the proportion of time that the international normalized ratio (INR) of patients receiving warfarin sodium was within the target therapeutic range +/- 0.2 INR units (expanded therapeutic range) while they were managed in anticoagulation clinics as opposed to family physicians' care over 3 months. We measured the rates of thromboembolic and major hemorrhagic events and patient satisfaction in the 2 groups. RESULTS: Of the 221 patients enrolled, 112 were randomly assigned to anticoagulation clinics and 109 to family physicians. The INR values of patients who were managed by anticoagulation clinics were within the expanded therapeutic range 82% of the time versus 76% of the time for those managed by family physicians (p = 0.034). High-risk INR values (defined as being < 1.5 or > 5.0) were more commonly observed in patients managed by family physicians (40%) than in patients managed by anticoagulation clinics (30%, p = 0.005). More INR measurements were performed by family physicians than by anticoagulation clinics (13 v. 11, p = 0.001). Major bleeding events (2 [2%] v. 1 [1%]), thromboembolic events (1 [1%] v. 2 [2%]) and deaths (5 [4%] v. 6 [6%]) occurred at a similar frequency in the anticoagulation clinic and family physician groups respectively. Of the 170 (77%) patients who completed the patient satisfaction questionnaire, more were satisfied when their anticoagulant management was managed through anticoagulation clinics than by their family physicians (p = 0.001). INTERPRETATION: Anticoagulation clinics provided better oral anticoagulant management than family physicians, but the differences were relatively modest.

Ambulatory Care Facilities↗
PubMed2003

Comparison of low-intensity warfarin therapy with conventional-intensity warfarin therapy for long-term prevention of recurrent venous thromboembolism.

BACKGROUND: Warfarin is very effective in preventing recurrent venous thromboembolism but is also associated with a substantial risk of bleeding. After three months of conventional warfarin therapy, a lower dose of anticoagulant medication may result in less bleeding and still prevent recurrent venous thromboembolism. METHODS: We conducted a randomized, double-blind study, in which 738 patients who had completed three or more months of warfarin therapy for unprovoked venous thromboembolism were randomly assigned to continue warfarin therapy with a target international normalized ratio (INR) of 2.0 to 3.0 (conventional intensity) or a target INR of 1.5 to 1.9 (low intensity). Patients were followed for an average of 2.4 years. RESULTS: Of 369 patients assigned to low-intensity therapy, 16 had recurrent venous thromboembolism (1.9 per 100 person-years), as compared with 6 of 369 assigned to conventional-intensity therapy (0.7 per 100 person-years; hazard ratio, 2.8; 95 percent confidence interval, 1.1 to 7.0). A major bleeding episode occurred in nine patients assigned to low-intensity therapy (1.1 events per 100 person-years) and eight patients assigned to conventional-intensity therapy (0.9 event per 100 person-years; hazard ratio, 1.2; 95 percent confidence interval, 0.4 to 3.0). There was no significant difference in the frequency of overall bleeding between the two groups (hazard ratio, 1.3; 95 percent confidence interval, 0.8 to 2.1). CONCLUSIONS: Conventional-intensity warfarin therapy is more effective than low-intensity warfarin therapy for the long-term prevention of recurrent venous thromboembolism. The low-intensity warfarin regimen does not reduce the risk of clinically important bleeding.

Age Factors↗
PubMed2003

Comparison of 10-mg and 5-mg warfarin initiation nomograms together with low-molecular-weight heparin for outpatient treatment of acute venous thromboembolism. A randomized, double-blind, controlled trial.

BACKGROUND: The optimal means of achieving therapeutic oral anticoagulation in the outpatient setting has not been determined. OBJECTIVE: To compare a 10-mg dosing nomogram with a 5-mg nomogram that has been suggested to be sufficient for warfarin initiation. DESIGN: Randomized, controlled clinical trial. SETTING: Outpatient venous thromboembolism services of four tertiary care hospitals. PATIENTS: 201 of 210 consecutive patients with objectively confirmed diagnoses of acute venous thromboembolism. INTERVENTION: All patients were treated with subcutaneous low-molecular-weight heparin for a minimum of 5 days until a therapeutic international normalized ratio (INR) was achieved. Patients were randomly assigned to initially receive a 10-mg or 5-mg dose of warfarin. MEASUREMENTS: The primary end point was time in days to therapeutic INR. Secondary end points were the proportion of patients who had achieved a therapeutic INR by day 5, the total number of INR assessments, the number of INR measurements greater than 5.0, incidence of recurrent venous thromboembolism and major bleeding, and survival. RESULTS: 210 consecutive patients met the inclusion criteria. Of these, 9 were excluded and 201 were randomly assigned to study groups (104 to the 10-mg group and 97 to the 5-mg group). Demographic characteristics of both groups were similar. Patients in the 10-mg group achieved therapeutic INR 1.4 days earlier than patients in the 5-mg group (P < 0.001). Eighty-three percent of patients in the 10-mg group achieved a therapeutic INR by day 5 versus 46% in the 5-mg group (P < 0.001). Fewer INR assessments were performed in the 10-mg group than in the 5-mg group (8.1 vs. 9.1; P = 0.04). There were no significant differences between the two groups in recurrent events, major bleeding, survival, and number of INR measurements greater than 5.0. CONCLUSION: The 10-mg warfarin initiation nomogram is superior to the 5-mg nomogram because it allows more rapid achievement of a therapeutic INR.

Acute Disease↗
PubMed2003

Endoluminal repair of aneurysms associated with coarctation.

BACKGROUND: Late aneurysm formation is a well-recognized complication of surgery for aortic coarctation. Open surgery to repair these aneurysms is associated with significant morbidity and mortality. Endoluminal repair is an attractive alternative to open surgery. METHODS: Data were collected prospectively on consecutive patients who presented with aneurysms associated with coarctation RESULTS: Between June 1999 and October 2001, 5 patients underwent elective endoluminal repair for coarctation aneurysms. All procedures were technically successful and no patients died. Four patients previously had open surgery to repair aortic coarctation, and 1 presented with an aneurysm associated with a previously unrecognized coarctation. The median follow-up was 7 months (range, 3 to 29 months), and to date, all aneurysms remain excluded. CONCLUSIONS: Endoluminal repair is a promising alternative to redo open surgery for thoracic aneurysms associated with previous surgery for aortic coarctation. Long-term follow-up is required to assess the durability of the stent grafts.

Adult↗
PubMed2003

Studies into the formation of dioxins in the sintering process used in the iron and steel industry. 1. Characterisation of isomer profiles in particulate and gaseous emissions.

Dioxin analyses using a DB5MS chromatography column are presented for samples of dust from an electrostatic precipitator and emissions from the main stack of a UK sinter plant. The analyses have been repeated using the SP2331 column, for which the elution order has been determined for the whole range of tetra to octachlorodibenzo-p-dioxins and dibenzofurans, and which provides a larger degree of separation than the DB5MS column. Polychlorinated dibenzofurans are present in significantly larger amounts in both the dust and stack emissions, and are the main contributors to the I-TEQ. Analysis using the SP2331 column for dioxins show considerable similarity to those of Bacher et al. for soot from a wood-burning fire, but differ markedly from those of Addink et al. for simulation of waste incineration. The similarities to Bacher's results are less for the dibenzofurans. Comparison of absolute concentrations with reported vapour pressures shows the retention of significant dioxin in the dust to involve mechanisms other than pure condensation.

Benzofurans↗