In vivo investigation of filter order influence in eigen-based clutter filtering for color flow imaging

Eigen-based adaptive filters have shown potential for providing a superior attenuation of clutter in color flow imaging. Critical for the success of this technique is the correct selection of filter order. In this work we review and compare filter order selection schemes for eigen-based filters in an in vivo context. Data was acquired from a thyroid tumor (PRF = 250 Hz, ensemble size = 12), where substantial tissue movement was present due to carotid artery pulsations, respiratory movements, and probe navigation. Eigen-filtering performance was evaluated for 1) an eigenvalue spectrum threshold, 2) a threshold on the ratio of successive eigenvalues, and 3) a threshold on eigenvector mean frequency estimated by the autocorrelation approach. Based on the observed eigenvalue and eigen-frequency distributions in analytical and in vivo examples, all filter order algorithms investigated suffered from potential pitfalls in specific Doppler scenarios. In the in vivo examples, the fixed order eigenfilter gave a sufficient suppression of clutter, but also removed substantial blood signal. Thresholding the ratio of eigenvalues better retained signal from blood, but also spurious artifacts was observed. The most consistent results were achieved by thresholding the mean frequency of the eigenvectors. The results demonstrate that given a suitable filter order algorithm, robust filtering can be achieved with the eigen-based approach. © 2007 IEEE.published_or_final_versio

Return to the workforce following first hospitalization for heart failure: a Danish nationwide cohort study

Background: Return to work is important financially, as a marker of functional status and for self-esteem in patients developing chronic illness. We examined return to work after first heart failure (HF) hospitalization. Methods: By individual-level linkage of nationwide Danish registries, we identified 21455 patients of working age (18-60 years) with a first HF hospitalization in the period of 1997-2012. Of these 11880 (55%) were in the workforce prior to HF hospitalization and comprised the study population. We applied logistic regression to estimate odds ratios (OR) for associations between age, sex, length of hospital stay, level of education, income, comorbidity and return to work. Results: One year after first HF hospitalization, 8040 (67.7%) returned to the workforce, 2981 (25.1%) did not, 805 (6.7%) died and 54 (0.5%) emigrated. Predictors of return to work included younger age (18-30 vs. 51-60 years, OR 3.12; 95% CI 2.42-4.03), male sex (OR 1.22 [1.18-1.34]) and level of education (long-higher vs. basic school OR 2.06 [1.63-2.60]). Conversely, hospital stay >7 days (OR 0.56 [0.51-0.62]) and comorbidity including history of stroke (OR 0.55 [0.45-0.69]), chronic kidney disease (OR 0.46 [0.36-0.59]), chronic obstructive pulmonary disease (OR 0.62 [0.52-0.75]), diabetes (OR 0.76 [0.68-0.85]) and cancer (OR 0.49 [0.40-0.61]) were all significantly associated with lower chance of return to work. Conclusions: Patients in the workforce prior to HF hospitalization had low mortality but high risk of detachment from the workforce one year later. Young age, male sex, and higher level of education were predictors of return to work

Long-Term Prognostic Importance of Diabetes After a Myocardial Infarction Depends on Left Ventricular Systolic Function

Objective: This study was performed to understand how left ventricular function modulates the prognostic importance of diabetes after myocardial infarction (MI). Research Design and Methods: Consecutively hospitalized MI patients screened for three clinical trials were followed for a median of 7 years. Multivariable Cox regression models were used to assess the risk of mortality associated with diabetes, and the importance of diabetes was examined independently within defined left ventricular ejection fraction (LVEF) subgroups. Results: A total of 16,912 patients were included; 1,819 (11%) had diabetes. Diabetes and 15% unit depression in LVEF were of similar prognostic importance: hazard ratios (HRs) were 1.45 (95% CI 1.37–1.54) and 1.41 (1.37–1.45) for diabetes and LVEF depression, respectively. LVEF modified the outcomes associated with diabetes, with HRs being 1.29 (1.19–1.40) and 1.61 (1.49–1.74) in patients with LVEF <40% and LVEF ≥40%, respectively (P = 0.03). Conclusions: Patients within the higher LVEF categories have a greater mortality risk attributable to diabetes than patients within the lower LVEF categories

Risk of death or reinfarction associated with the use of selective cyclooxygenase-2 inhibitors and nonselective nonsteroidal antiinflammatory drugs after acute myocardial infarction

Udgivelsesdato: 2006-Jun-27BACKGROUND: The selective cyclooxygenase-2 (COX-2) inhibitors and other nonselective nonsteroidal antiinflammatory drugs (NSAIDs) have been associated with increased cardiovascular risk, but the risk in patients with established cardiovascular disease is unknown. We analyzed the risk of rehospitalization for acute myocardial infarction (MI) and death related to the use of NSAIDs including selective COX-2 inhibitors in patients with prior MI. METHODS AND RESULTS: All patients with first-time MI between 1995 and 2002 as well as all prescription claims for NSAIDs after discharge were identified from nationwide Danish administrative registers. The risk of death and rehospitalization for MI associated with the use of selective COX-2 inhibitors and nonselective NSAIDs was studied with the use of multivariable proportional hazards models and case-crossover analysis. A total of 58 432 patients were discharged alive and included in the study; 9773 experienced rehospitalization for MI, and 16 573 died. A total of 5.2% of patients received rofecoxib, 4.3% celecoxib, 17.5% ibuprofen, 10.6% diclofenac, and 12.7% other NSAIDs. For any use of rofecoxib, celecoxib, ibuprofen, diclofenac, and other NSAIDs, the hazard ratios and 95% confidence intervals for death were 2.80 (2.41 to 3.25; for rofecoxib), 2.57 (2.15 to 3.08; for celecoxib), 1.50 (1.36 to 1.67; for ibuprofen), 2.40 (2.09 to 2.80; for diclofenac), and 1.29 (1.16 to 1.43; for other NSAIDS); there were dose-related increases in risk of death for all of the drugs. There were trends for increased risk of rehospitalization for MI associated with the use of both the selective COX-2 inhibitors and the nonselective NSAIDs. CONCLUSIONS: Selective COX-2 inhibitors in all dosages and nonselective NSAIDs in high dosages increase mortality in patients with previous MI and should therefore be used with particular caution in these patients

Persistent use of evidence-based pharmacotherapy in heart failure is associated with improved outcomes

Udgivelsesdato: 2007-Aug-14BACKGROUND: Undertreatment with recommended pharmacotherapy is a common problem in heart failure and may influence prognosis. We studied initiation and persistence of evidence-based pharmacotherapy in 107,092 patients discharged after first hospitalization for heart failure in Denmark from 1995 to 2004. METHODS AND RESULTS: Prescriptions of dispensed medication and mortality were identified by an individual-level linkage of nationwide registers. Inclusion was irrespective of left ventricular function. Treatment with renin-angiotensin inhibitors (eg, angiotensin-converting enzyme inhibitors and angiotensin-2 receptor blockers), beta-blockers, spironolactone, and statins was initiated in 43%, 27%, 19%, and 19% of patients, respectively. Patients who did not initiate treatment within 90 days of discharge had a low probability of later treatment initiation. Treatment dosages were in general only 50% of target dosages and were not increased during long-term treatment. Short breaks in therapy were common, but most patients reinitiated treatment. Five years after initiation of treatment, 79% patients were still on renin-angiotensin inhibitors, 65% on beta-blockers, 56% on spironolactone, and 83% on statins. Notably, multiple drug treatment and increased severity of heart failure was associated with persistence of treatment. Nonpersistence with renin-angiotensin inhibitors, beta-blockers, and statins was associated with increased mortality with hazard ratios for death of 1.37 (95% CI, 1.31 to 1.42), 1.25 (95% CI, 1.19 to 1.32), 1.88 (95% CI, 1.67 to 2.12), respectively. CONCLUSIONS: Persistence of treatment was high once medication was started, but treatment dosages were below recommended dosages. Increased severity of heart failure or increased number of concomitant medications did not worsen persistence, but nonpersistence identified a high-risk population of patients who required special attention. A focused effort on early treatment initiation, appropriate dosages, and persistence with the regimen is likely to provide long-term benefit

Statin treatment and risk of recurrent venous thromboembolism: a nationwide cohort study

Statins may decrease the risk of primary venous thromboembolism (VTE), that is, deep vein thrombosis (DVT) and pulmonary embolism (PE) but the effect of statins in preventing recurrent VTE is less clear. The aim of this study was therefore to investigate the association between statin therapy and risk of recurrent VTE. A prospective cohort study. All hospitals in Denmark. All patients with a hospital diagnosis of VTE in Denmark during 1997-2009 associated with a warfarin or heparin prescription were identified. Adjusted HR of recurrent hospitalised VTE (ie, fatal or non-fatal DVT or PE) associated with use of statins. 44 330 patients with VTE were included in the study. Of these 3914 were receiving statin therapy at baseline. Patients receiving statins were older (68±11 compared to 62±18 years), had more comorbidity and used more medications. The incidence rate for recurrent VTE was 24.4 (95% CI 22.8 to 26.2) per 1000 person-years among statin users and 48.5 (95% CI 47.4 to 49.7) per 1000 person-years among non-statin users. Statin use was associated with a significantly lower risk of a recurrent VTE, adjusted HR 0.74 (95% CI 0.68 to 0.80), compared with no statin use. The association between statin use and risk of recurrent VTE was significantly affected by age. Among younger individuals (≤80 years), statin use was associated with lower risk of recurrent VTE, HR 0.70 (95% CI 0.65 to 0.76) whereas in older individuals (>80 years) statin use was significantly associated with higher risk of recurrent VTE, HR 1.28 (95% CI 1.02 to 1.60), p for interaction= <0.0001. Statin use was associated with a decreased risk of recurrent VT

Atrial fibrillation pharmacotherapy after hospital discharge between 1995 and 2004: a shift towards beta-blockers.

Udgivelsesdato: 2008-AprAIMS: To study evolvement in pharmacotherapy of atrial fibrillation from 1995 to 2004. METHODS AND RESULTS: All Danish patients were discharged following first-time atrial fibrillation and their pharmacotherapy was identified by individual-level-linkage of nationwide registers of hospitalization and drug dispensing from pharmacies. A total of 108 791 patients survived 30 days after discharge and were included. In 1995-1996, 7.4% of the patients received beta-blockers, increasing to 44.3% in 2003-2004. The corresponding figures for amiodarone were 2.9 and 5.4%. In contrast, use of nondihydropyridine calcium-channel blockers, digoxin, sotalol, and class 1C antiarrhythmics decreased from 20.6, 63.9, 21.3, and 4.0% in 1995-1996 to 12.6, 43.8, 4.2, and 1.3% in 2003-2004, respectively. Notably, patients receiving anticoagulants increased from 29.8 to 43.5%. Multivariate logistic regression analysis revealed females to be associated with more use of digoxin, but less use of amiodarone and oral anticoagulants than males. Patients above 80 years received less pharmacotherapy, apart from digoxin treatment that was more commonly used in elderly. CONCLUSION: Pharmacotherapy of atrial fibrillation has changed towards increased beta-blocker use with a coincident decrease in the use of other rate-limiting drugs and sotalol. Treatment with amiodarone or class 1C antiarrhythmics remained very low. Oral anticoagulant therapy increased considerably, but women and elderly were apparently undertreated

Dabigatran use in Danish atrial fibrillation patients in 2011: a nationwide study

OBJECTIVE: Dabigatran was recently approved for anticoagulation in patients with atrial fibrillation (AF); data regarding real-world use, comparative effectiveness and safety are sparse. DESIGN: Pharmacoepidemiological cohort study. METHODS/SETTINGS: From nationwide registers, we identified patients with an in-hospital or outpatient-clinic AF diagnosis who claimed a prescription of dabigatran 110 or 150 mg, or vitamin K antagonist (VKA), between 22 August and 31 December 2011. HRs of thromboembolic events (ischaemic stroke, transitory ischaemic attack and peripheral artery embolism) and bleedings were estimated using Cox regression analyses in all patients and stratified by previous VKA use. RESULTS: Overall, 1612 (3.1%) and 1114 (2.1%) patients claimed a prescription of dabigatran 110 and 150 mg, and 49640 (94.8%) of VKA. Patients treated with dabigatran 150 mg were younger with less comorbidity than those treated with dabigatran 110 mg and VKA, as were VKA naïve patients compared with previous VKA users. Recommendations set by the European Medicine Agency (EMA) for dabigatran were met in 90.3% and 55.5% of patients treated with 110 and 150 mg. Patients treated with 150 mg dabigatran, who did not fulfil the recommendations by EMA, were >80 years, patients with liver or kidney disease, patients with previous bleeding. Compared with VKA, the thromboembolic risk associated with dabigatran 110 and 150 mg was HR 3.52 (1.40 to 8.84) and 5.79 (1.81 to 18.56) in previous VKA users, and HR 0.95(0.47 to 1.91) and 1.14(0.60 to 2.16) in VKA naïve patients. Bleeding risk was increased in previous VKA users receiving dabigatran 110 mg, but not in patients with 150 mg dabigatran, nor in the VKA naïve users. CONCLUSIONS: Deviations from the recommended use of dabigatran were frequent among patients treated with 150 mg. With cautious interpretation, dabigatran use in VKA naïve patients seems safe. Increased risk of thromboembolism and bleeding with dabigatran among previous VKA users was unexpected and may reflect patient selection and ‘drug switching’ practices