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Biomedical subjects

C A Schneider

Publications and source records attributed to C A Schneider.

At least 19 recordsLinked to original sources
PubMed2004

[Hyperglycemia and cardiovascular events].

Besides classical, modifiable risk factors (hypercholesterolemia, hypertension, smoking) abnormalities of the glucose metabolism (diabetes mellitus, impaired glucose tolerance) are strong emerging cardiovascular risk factors. Epidemiological data indicate that 8 % of the population and up to 60 % of patients with coronary artery disease have abnormalities of glucose metabolism. The prevalence of these abnormalities will increase as the population ages and the mean body weight increases. An abnormal glucose concentration damages the endothelium in several ways: increased oxidative stress, inflammatory processes and an activation of procoagulant factors all impair endothelial function. A blood glucose normalising therapy is thought to decrease the incidence of cardiovascular events in these patients. In patients with an acute myocardial infarction and diabetes mellitus an early intensive insulin therapy improves the outcome of these patients. In summary, the early detection and treatment of abnormalities of glucose metabolism reduces cardiac events.

Cardiovascular Diseases↗
PubMed2004

Use of NT-proBNP in routine testing and comparison to BNP.

OBJECTIVES: B-type natriuretic peptide (BNP) is a strong diagnostic predictor of left-ventricular (LV)-dysfunction. Recently, the aminoterminal portion of pro-BNP (NT-proBNP) has been introduced, which could be even more sensitive because of its longer half-life. The aim of this study was to evaluate the new marker NT-proBNP within a large, heterogeneous population of patients with suspected cardiovascular disease at risk of cardiovascular dysfunction and to compare it with the established diagnostic parameter BNP. SUBJECTS AND METHODS: NT-proBNP and BNP were measured in 339 hospitalised patients undergoing diagnostic angiography (median age 66 years, 244 male vs. 95 female). RESULTS: Median values of NT-proBNP increased with worsening LV-dysfunction and higher NYHA class. The area under the receiver operator characteristics curve (AUC) of NT-proBNP for detecting severe systolic dysfunction or for detecting any systolic LV-dysfunction was 0.83 and 0.77, respectively. The latter improved (AUC=0.81) when patients with clinically relevant heart disease like valvular dysfunction were included, independent of the haemodynamic values. Compared to BNP, NT-proBNP tended to be more accurate in identifying lesser degrees of LV-dysfunction. CONCLUSIONS: Even after optimisation of target criteria, there was still a substantial overlap of NT-proBNP values between patients with and without relevant heart disease. Therefore, NT-proBNP is not suitable as a screening test for LV-dysfunction in the community. Nevertheless, because of its good negative predictive value, NT-proBNP could be an easy and effective tool to rule out severe systolic LV-dysfunction in high risk patients. No clinically significant advantage of BNP testing could be found.

Aged↗
PubMed2004

[Secondary prevention of cardiovascular diseases].

Secondary prevention includes all measures to lower the risk of a relapse of a specific disease. For secondary prevention of cardiovascular diseases general measures and specific drug therapy are employed, according to the individual risk pattern. Among the general measures cessation of smoking is most important. In addition, an increase in daily exercise, a normalization of body weight and a healthy diet all lower the cardiovascular risk. For most cases secondary prevention includes also specific drug therapies. Aspirin, statins and beta-blockers are the cornerstones of this drug therapy. After myocardial infarction most patients will also benefit from an ACE-inhibitor therapy.

Adrenergic beta-Antagonists↗
PubMed2004

[The PreFord Study. A prospective cohort study to evaluate the risk of a cardiovascular event (overall-collective) as well as a prospective, randomized, controlled, multicentre clinical intervention study (high-risk-collective) on primary prevention of cardiovascular diseases in the Ford Motor Company employees in Germany].

The PreFord Study is a multicenter prospective cohort study to evaluate guideline based risk management on primary prevention of cardiovascular diseases. Furthermore a randomised controlled trial (RCT) will be designed to analyse the effect of a special intervention program. 40,000 employees of the Ford Motor Company, Visteon Company and Deutz Company in Germany will be included, monitored for ten years and the following primary endpoints will be investigated: 1. evaluation and comparison of established and newly developed risk-scores, 2. the relative impact of single and combined cardiovascular risk factors on cardiovascular diseases, 3. the influence of a novel occupationally integrated ambulant rehabilitation program in combination with a guideline oriented optimal drug therapy within a high risk group on the primary endpoint: risk reduction by, 4. the influence of this intervention on secondary endpoints: death, myocardial infarction and stroke, combined appearance of angina pectoris and hospitalisation, occurrence of cerebral circulatory disorder and hospitalisation, occurrence of peripheral occlusive arterial disease and hospitalisation and single cardiovascular risk factors and cost-benefit-analysis. Beginning with an cross sectional study there will be a systemic screening of cardiovascular risk profiles, of anthropometric data and different lifestyle-factors. Based on these data participants will be differentiated into three risk-groups according to the risk score of the European Society of Cardiology (risk of a lethal primary acute cardiovascular event: I < or = 1%; II > 1-< 5% and III > or = 5%). In the following longitudinal study different strategies will be applied: Group I: low risk (< 0.5% per year): repetition of the investigation after five and ten years. Group II: middle risk, (0.6% to 1.4% per year), repetition of the investigation every two years, instruction of the patients general practitioner (GP) with respect to a risk factor oriented and evidence based treatment. Group III: high risk, (> 1.5% per year or >15% within the next 10 years) will be randomised into two interventional groups. The first one, the intervention-group "PreFord" will perform an occupational integrated rehabilitation program (2,5-3 hours twice a week, for 15 weeks according to the BAR guidelines) with a following engagement in heart-groups and an annual repetition of the check-ups. The second group, the "classic" intervention-group will be treated evidence based in cooperation with their GP. As a result of this long term interventional study efficient, area wide implementable and economically feasible prevention concepts with special regards to operational healthcare will be developed and evaluated. Core elements will be exercise- and lifestyle-oriented concepts as well as guideline-based pharmacotherapy.

Adult↗
PubMed2004

Natriuretic peptides BNP and NT-pro-BNP: established laboratory markers in clinical practice or just perspectives?

A growing body of literature describes diagnostic and prognostic value of B-type natriuretic peptides (BNP) in cardiac diseases since it was first described in 1988. As BNP is mainly secreted in the left ventricular (LV) myocardium, BNP was found to reflect LV function much better than any other neurohumoral factor. Thus, BNP is recommended as the first noninvasive blood test for determination of cardiac function by some authors. The introduction of fully automated, rapid bioassays for measurement of BNP and the aminoterminal part of its pro-hormone (NT-pro-BNP) made it possible to use the test even in emergency care settings. Here we review the literature with special focus on assessment of BNP and NT-pro-BNP in the following clinical settings: community screening for LV dysfunction, primary diagnosis of heart failure in general practice and emergency department (ED) and risk stratification in cardiac dysfunction and acute coronary syndromes. In addition, we discuss which applications can be recommended for daily clinical use from the cardiologist's point of view.

Coronary Disease↗
PubMed2002

[The value of natriuretic peptides NT-pro-BNP and BNP for the assessment of left-ventricular volume and function. A prospective study of 150 patients].

BACKGROUND AND OBJECTIVE: An early detection of patients with left-ventricular (LV) dysfunction is essential for effective treatment of congestive heart failure. The B-type natriuretic peptide (BNP) was described as a strong diagnostic parameter of LV-dysfunction. Aim of this study was to compare the diagnostic value of BNP and the aminoterminal part of pro-BNP (NT-pro-BNP) within an heterogenous patient population. SUBJECTS AND METHODS: NT-pro-BNP and BNP were measured in 150 hospitalized cardiologic patients (age-median 64 years, 109 male versus 41 female). The values were correlated with clinical and haemodynamic parameters of the invasively determined LV-function. RESULTS: Patients with pathologic haemodynamic values of the LV-function had significantly higher NT-pro-BNP and BNP levels than patients with normal haemodynamic parameters. In our study population a severe systolic LV-dysfunction (ejectionfraction EF<40 %) could be detected with a sensitivity and specifity of 100 % and 64 % by NT-pro-BNP and 100 % and 45 % by BNP. Sensitivity and specifity for the detection of any systolic dysfunction (EF<60 %) and of a systolic or diastolic dysfunction, respectively, were 94 %, 37 % and 88 %, 41 % for NT-pro-BNP (94 %, 40 % and 84 %, 44 % for BNP). The corresponding negative predictive values were 100 %, 96 % and 71 % for NT-pro-BNP and 100 %, 96 % and 68 % for BNP. CONCLUSION: NT-pro-BNP and BNP were highly sensitive diagnostic parameters with a very good negative predictive value for LV-dysfunction. Because of the uncomplicated measurement, they could be used effectively to rule out LV-dysfunction in cardiovascular high risk patients by general practitioners.

Adult↗
PubMed2001

Non-Q-wave myocardial infarction: impaired myocardial energy metabolism in regions with reduced 99mTc-MIBI accumulation.

Reduced regional technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) accumulation in patients with chronic non-Q-wave infarction (NQWI) but without significant coronary artery stenosis indicates non-transmural damage of the myocardial wall. The aim of this study was to characterise cardiac energy metabolism after NQWI using phosphorus-31 magnetic resonance spectroscopy (31P-MRS) and to compare the biochemical remodelling with changes in regional 99mTc-MIBI uptake and with morphological and functional parameters assessed by magnetic resonance imaging (MRI). Fifteen patients with a history of NQWI, exclusion of significant coronary artery stenosis (<50% diameter stenosis) and hypokinesia of the anterior wall (group A) were examined with 31P-MRS to study the effects of NQWI on myocardial energy metabolism. Spectroscopic measurements were performed in the infarct-related myocardial region. Corresponding gradient-echo MR images and myocardial 99mTc-MIBI single-photon emission tomography images were acquired for exact localisation of the infarct region. All examinations were performed at rest under anti-ischaemic medication. Data were compared with those of patients in whom coronary artery disease had been excluded by angiography (group B, n=10). All patients of group A displayed anterior wall hypokinesia in the infarcted area on both ventriculography and MRI, with a reduced myocardial accumulation of 99mTc-MIBI (66.3%+/-11.8% vs 95.6%+/-2.2% in group B). The mean wall thickness during the complete cardiac cycle (9.5+/-1.8 mm vs 13.1+/-1.1 mm in group B, P<0.001), the systolic wall thickening (2.6+/-1.4 mm vs 5.8+/-1.5 mm in group B, P<0.01) and the phosphocreatine/adenosine triphosphate ratio (1.12+/-0.22 vs 1.74+/-0.23 in group B, P<0.01) in the hypokinetic area were all significantly reduced. It is concluded that persisting hypokinetic myocardium after NQWI combined with reduced myocellular uptake of 99mTc-MIBI displays a reduced PCr/ATP ratio. Our results indicate that morphological remodelling after NQWI is accompanied by fundamental changes in cardiac energy metabolism.

Adenosine Triphosphate↗
PubMed2001

Hypertension guidelines and their limitations--the impact of physicians' compliance as evaluated by guideline awareness.

OBJECTIVE: The initial step of an optimal therapeutic strategy for patients with arterial hypertension is the recognition and acceptance of new recommendations by the physicians themselves. This guideline awareness of the physicians has never been evaluated in detail. DESIGN: The awareness of content of current recommendations in hypertension diagnosis, treatment and treatment control was therefore assessed in primary care physicians using a questionnaire. The guidelines of the German Hypertension Society were used as the reference standard. PARTICIPANTS: A total of 24 899 German physicians, including all internists, all cardiologists and 22% of general practitioners were contacted in a nationwide survey. MAIN OUTCOME MEASURES: The number of answers in agreement with the guideline was used as a measure of guideline awareness. Adequate awareness of content of guideline recommendations was defined as the correct answer to five out of eight questions; the correct answers had to include the appropriate definition of hypertension. RESULTS: The analysis was based on 11 547 returned questionnaires (47.1%). An adequate guideline awareness was found in 23.7% of the total study population, especially in 37.1% of cardiologists, in 25.6% of internists and in 18.8% of general practitioners. While the guideline awareness was significantly influenced by the duration of private practice, regional and municipal factors had only minor influence on the results. CONCLUSION: The impact of hypertension guidelines on actual medical knowledge is modest. Thus, the information strategies about current treatment guidelines must be improved and tailored to the needs of physicians in clinical practice to ultimately improve patient care.

Awareness↗
PubMed2001

[Guideline-adequate knowledge in internists and general practitioners about the diagnosis and treatment of arterial hypertension].

Only a small proportion of patients with arterial hypertension are adequately treated. Although a possible cause for this fact may be the deficient knowledge of physicians about diagnosis and treatment of arterial hypertension, to date no studies have addressed this important problem in Germany. Therefore, we have reviewed the knowledge of internists and general practitioners about diagnosis and treatment of arterial hypertension using a questionnaire. The guidelines of the German Hypertension Society were used as the reference standard. The questionnaire was sent out in December 1999 to all internists (n = 15,952) and to a random sample of general practitioners (n = 8947) who work as statutory health insurance physicians. A total of 11,547 questionnaires were sent back and could be analysed. Adequate guideline knowledge was assumed if five out of eight questions were correctly answered; the correct answers had to include the correct definition of arterial hypertension (> 140/90 mmHg). The correct definition of arterial hypertension was known by 4103/11,547 participants (36%). An adequate guideline knowledge was found in 18.8% of the general practitioners and in 26.6% of the internists. There were no relevant regional differences. The level of awareness about diagnosis and treatment of arterial hypertension is insufficient among internists and general practitioners. This insufficient knowledge may in part explain the inadequate care for patients with arterial hypertension. Thus, the implementation and evaluation of new information and training strategies are mandatory to improve the care for patients with arterial hypertension.

Family Practice↗
PubMed2001

[Comparison of dobutamine-stress magnetic resonance imaging and dipyridamole-TL-201-SPECT as alternative strategies for the detection of coronary artery dis in patients no suitable for stress echocardiography].

AIM: During the past decade stress-echocardiography has gained increasing popularity for detection of myocardial ischemia in patients with coronary artery disease. However, about 10% to 15% of the patients submitted for stress-echocardiography do not have an adequate acoustic window. The purpose of this study was to compare high-dose dobutamine-stress magnetic resonance imaging (dobutamine-MRI) with dipyridamole-Tl-201-SPECT (dipyridamole-SPECT) as alternative strategies for detection of myocardial ischemia in patients with inadequate image quality by stress-echocardiography. PATIENTS AND METHODS: Of 296 patients which were consecutively submitted to stress-echocardiography 45 patients (15%) had two or more segments that could not be evaluated according to the 16-segment-model of the American Society of Echocardiography. They underwent dobutamine-MRI and dipyridamole-SPECT studies, which were evaluated using a 28-segment modell. Myocardial segments were attributed to perfusion territories of the coronary arteries. The results of ischemia detection were compared to the results of coronary angiography (stenosis > or = 50%). RESULTS: In comparison to coronary angiography dobutamine-MRI yielded a sensitivity of 87%, a specificity of 86%, a positive predictive value of 93%, a negative predictive value of 75% and a diagnostic accuracy of 86%. For dipyridamole-SPECT results were 90%, 86%, 93%, 80% and 89%, respectively. These values were not significantly different. CONCLUSIONS: In patients not suitable for stress-echocardiography, both dobutamine-MRI and dipyridamole-SPECT are reliable strategies for detection of myocardial ischemia. Selection is dependent on the patient criteria, technical considerations, local logistics and experience of the observer.

Adrenergic beta-Agonists↗
PubMed2000

In vivo uptake of azithromycin in human coronary plaques.

Ten patients with symptomatic coronary artery disease received oral azithromycin for 3 days and underwent directional atherectomy on the third day. Azithromycin was found in all plaque samples with a median concentration of 284 ng/ml (95% confidence interval 163 to 517 ng/ml).

Anti-Bacterial Agents↗
PubMed2000

[Dobutamine-induced changes in the myocardial blood flow in patients with coronary heart diseases. A quantitative analysis using [15O] H2O positron emission tomography].

BACKGROUND AND OBJECTIVE: Although dobutamine is currently widely used for stress testing, only little is known about the effects of dobutamine on myocardial blood flow. The purpose of the present study was therefore to analyze quantitatively the regional changes in myocardial blood flow during rest and stress. PATIENTS AND METHODS: In order to assess these effects 17 patients (12 men, five women, mean age 57 +/- 8 years) with symptomatic single vessel coronary artery disease (> 70% stenosis) scheduled for coronary angioplasty underwent dobutamine stress testing with a maximum dose of 40 micrograms/kg/min. Myocardial blood flow was measured using 15O H2O position emission tomography at rest and during maximum stress in ischemic and non-ischemic myocardial regions. RESULTS: Dobutamine stress (median dose 30 micrograms/kg/min) increased the rate pressure product significantly (from rest 8697 [95% confidence interval 7959-9435] to stress 16,512 [15,208-17,815] mmHg/min (p < 0.001). Myocardial blood flow during rest was similar in non-ischaemic and ischaemic regions (0.91 [0.93; 0.83-1.28] vs. 1.10 [1.23; 0.91-1.28] ml/min/g, n.s.). During dobutamine stress myocardial blood flow increased in non-ischaemic regions to 2.17 (2.15; 1.77-2.57) ml/min/g, while myocardial blood flow did not increase in ischaemic regions (1.06 [0.97; 0.83-1.28], p < 0.001). Accordingly, dobutamine coronary reserve was 2.42 (2.55; 2.10-2.74) for non-ischaemic regions and 0.98 (1.05; 0.84-1.13) for ischemic regions (p < 0.001). Rate pressure product and myocardial blood flow were significantly correlated (r = 0.79, p < 0.001). CONCLUSION: A dobutamine-induced increase in rate pressure product was proportional to an increase in myocardial blood flow in non-ischaemic regions. In contrast, myocardial blood flow did not increase in myocardial regions supplied by a severely stenosed coronary artery.

Blood Flow Velocity↗