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W Niederer

Publications and source records attributed to W Niederer.

At least 19 recordsLinked to original sources
PubMed2005

In-hospital time to treatment of patients with acute ST elevation myocardial infarction treated with primary angioplasty: determinants and outcome. Results from the registry of percutaneous coronary interventions in acute myocardial infarction of the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausarzte.

OBJECTIVE: To determine the predictors of time between presentation and primary angioplasty and the influence of this delay time on in-hospital mortality in clinical practice. DESIGN: Analysis of data from the registry of percutaneous coronary interventions in acute myocardial infarction of the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausärzte (ALKK). PATIENTS: Data of 4815 patients registered at 80 hospitals between 1994 and 2000 were analysed. RESULTS: Mean age of the patients was 61.4 (12.5) years. Cardiogenic shock was present in 14.1%. Mean time from admission to primary angioplasty ("door to angiography" time) was 83 (122) minutes. Logistic regression analysis showed the presence of a bundle branch block (odds ratio (OR) 1.95, 95% confidence interval (CI) 1.15 to 3.29), prior coronary artery bypass grafting (OR 1.67, 95% CI 1.08 to 2.59), pre-hospital delay > 3 hours (OR 1.61, 95% CI 1.37 to 1.89), and female sex (OR 1.21, 95% CI 1.01 to 1.45) to be independently associated with longer door to angiography times, whereas a higher hospital volume of performing primary angioplasty (OR 0.53, 95% CI 0.46 to 0.62) and the year of the investigation (OR 0.96, 95% CI 0.92 to 1.00) were independently associated with shorter door to angiography times. Independent predictors of in-hospital mortality were cardiogenic shock (41.6% v 4.0% without cardiogenic shock, p < 0.0001), technical success (29.2% with TIMI (thrombolysis in myocardial infarction) flow < 3 v 6.5% with TIMI flow 3, p < 0.0001), age (16.5% > or = 70 years v 6.6% < 70, p < 0.0001), three vessel disease (16.5% v 6.8% with < 3 vessel disease, p < 0.0001), anterior location of infarction (12% v 7.4% without anterior infarction, p < 0.0001), year of inclusion (adjusted OR 0.92 per year, p = 0.011), and volume of primary angioplasty at the hospital (11% for < 20 angioplasty procedures/year v 8.3% for > or = 20/year, p = 0.027) but not the door to angiography time (adjusted OR 1.14 per tertile, p = 0.397). CONCLUSIONS: In current clinical practice in Germany median door to angiography time is quite short (83 (122) minutes). Some patients and hospital factors are independently associated with a longer door to angiography time. Within the observed short in-hospital delays door to angiography time did not influence in-hospital mortality. However, efforts to keep them as short as possible should be continued.

Angioplasty, Balloon, Coronary↗
PubMed1998

Direct percutaneous transluminal coronary angioplasty in acute myocardial infarction. Predictors of short-term outcome and the impact of coronary stenting. Study Group of The Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausärzte (ALKK).

BACKGROUND: Direct percutaneous transluminal coronary angioplasty (PTCA) is widely accepted in the treatment of acute myocardial infarction since excellent results had been reported from several small randomized trials. Less favourable results were observed in large-scale registries. In particular, the use of stents in acute myocardial infarction has become common practice without documented evidence of clinical efficacy. METHODS: Data were analysed from a registry of all consecutive percutaneous transluminal coronary angioplasty procedures from 62 centres in Germany, including 2331 direct percutaneous transluminal coronary angioplasty in acute myocardial infarction from July 1994 to April 1997. RESULTS: The overall angiographic success rate of percutaneous transluminal coronary angioplasty, defined as complete antegrade perfusion of the infarct vessel, was 87%. In-hospital mortality was 11.2%. The most important predictor of death was the presence of cardiogenic shock in 15% of patients, of whom 52% died. Mortality in patients without shock was 3.9%. Failed percutaneous transluminal coronary angioplasty was associated with a mortality of 36%. Further independent predictors of death were older age, multivessel disease, and anterior myocardial infarction. Stents were used in 4.1% of the procedures in 1994, increasing to 53% in 1997. However, this was not accompanied by improved clinical outcome. Mortality with coronary stenting was 9.9% vs 11.6% without stents (ns). CONCLUSIONS: Direct percutaneous transluminal coronary angioplasty is a valuable treatment strategy in acute myocardial infarction, although the results are less exceptional than reported from some highly specialized centres. Failed percutaneous transluminal coronary angioplasty seems to be harmful, thus outweighing much of the benefit from successful procedures. Stents did not improve the clinical outcome significantly, despite technically successful placement in 98%. Mortality from cardiogenic shock continues to be excessively high despite direct PTCA.

Adult↗
PubMed1998

HBW 023 (recombinant hirudin) for the acceleration of thrombolysis and prevention of coronary reocclusion in acute myocardial infarction: results of a dose-finding study (HIT-II) by the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausärzte.

OBJECTIVE: To define an optimal dose of hirudin that would improve early coronary artery Thrombolysis in Myocardial Infarction grade 3 (TIMI 3) patency and prevent reocclusions in patients with acute myocardial infarction treated with front-loaded recombinant tissue-type plasminogen activator (rt-PA). METHODS: Recombinant hirudin (HBW 023) was tested in a sequential dose-escalating study as adjunct to front-loaded rt-PA in 143 patients with acute myocardial infarction. The sequential model was assigned two 'decision boundaries': it triggered an increase in dosage if the 60-min TIMI 3 flow rate in a dosage group was statistically not consistent with a target patency rate of 75%, or if the deterioration in coronary blood flow (of at least one TIMI grade, from TIMI 2 or 3, from one angiography to the next) exceeded 5%. RESULTS: The decision boundary for TIMI 3 flow grade at 60 min was crossed when 18 patients were treated with 0.1/0.06 mg/kg (bolus/infusion per hour over 48 h) r-hirudin (dosage group I), 42 patients treated with 0.2/0.1 mg/kg (dosage group II), and 83 patients with 0.4/0.15 mg/kg (dosage group III). TIMI 3 flow at 60 min was 50%, 58%, and 63% in dosage groups I-III, respectively (P = 0.15). Early, complete, and sustained patency (TIMI 3 flow at 60 min, 90 min and 48 h) were 44%, 55% and 64% (P = 0.07). Reocclusion between 90-min and 48-h angiograms or reinfarction occurred in 0 to 15, two of 36, and one of 72 patients, respectively (P = 0.5). Four patients (2.8%) died in hospital and 14 patients suffered a major bleeding event, but no intracranial bleeding was encountered. CONCLUSIONS: With increasing doses of hirudin, there was a trend towards greater early and complete patency, but no clear dose--response relationship was observed. A borderline significant effect was observed with respect to early, complete, and sustained patencies. In all groups, reocclusions or reinfarctions were rare. Neither clinical nor laboratory data predicted the imbalance in haemorrhagic events observed in a subsequent, prematurely terminated, phase III trial with hirudin and rt-PA.

Adult↗
PubMed1997

PTCA registry of German community hospitals. Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausärzte (ALKK) Study Group.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) is widely used, but no quality control has been systematically performed as yet. METHODS: A registry of all PTCA procedures has been established since October 1992 for the majority of the German community hospitals performing PTCA, representing about one third of all PTCA activity in Germany. Baseline demographic data, indication for PTCA, primary success and in-hospital clinical events were recorded. Each centre was visited at regular intervals to assure completeness and reliability of the data. RESULTS: Of 52453 procedures performed from October 1992 to December 1994 the catheter laboratory and discharge forms were 99.7% and 98.1% complete, respectively. In 85.9% a single lesion was dilated per procedure, but 48.7% of the patients had multivessel disease. The success rate was 66.5% in complete occlusions (residual stenosis < 70%) and 91.2% in non-occluded vessels (residual stenosis < 50%). Abrupt vessel closure occurred in 3.4%, of which 77.5% could be recanalized by repeat intervention. In procedures not done for acute myocardial infarction, the in-hospital mortality was 0.52%, the procedure-related mortality 0.37%. In 3.02% of all patients a severe complication occurred (procedure-related death, myocardial infarction or emergency bypass surgery). CONCLUSION: Complete recording of all PTCA procedures is feasible even on a nationwide basis. This is a pre-requisite for continuous quality control. The reporting of the procedures by itself very probably, has an impact on the quality which is, however, not measurable quantitatively.

Aged↗
PubMed1996

Cardioversion of atrial fibrillation in the elderly. ALKK-Study Group. Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausaerzte.

The purpose of this investigation was to define cardioversion success rates, frequency of complications of cardioversion, and current treatment practices in elderly patients (aged > or = 65 years) with atrial fibrillation (AF). The results were compared with those in younger patients (aged < 65 years). The investigation was a prospective multicenter observational study with 61 participating cardiology clinics. Consecutive patients in whom cardioversion of AF was planned had to be prospectively registered. Of 1,152 patients registered, 570 (49.5%) were < 65 years old (group 1) and 582 (50.5%) were > or = 65 years (group 2). The overall success rate of cardioversion on an intention-to-treat basis was 76.1% in group 1 and 72.7% in group 2 (p = 0.18). In multivariate analysis, left atrial size and New York Heart Association functional class before cardioversion were identified as predictors of success (p < 0.001, respectively; p = 0.025). These clinical factors were not equally distributed between the age groups: Left atrial size was larger in the elderly than in younger patients (44.0 +/- 6.4 mm vs 42.8 +/- 6.4 mm; p = 0.006) and a New York Heart Association functional class > or = II was more prevalent in group 2 than in group 1 (48.6% vs 29.6%; p < 0.001). The overall complication rates were not significantly different between the 2 groups (4.2% in group 1 vs 5.3% in group 2; p = 0.37). The frequency of patients who were adequately anticoagulated for cardioversion was 56.9% in age group 1 and 39.6% in age group 2 (p < 0.001). In chronic AF the same trend for age-dependent underuse of anticoagulation was observed. Age itself was not a predictor of cardioversion success and did not predispose to higher complication rates. Therefore, cardioversion should be considered in older patients with the same criteria and emphasis as in younger patients. Anticoagulation and antithrombotic medication is underused for cardioversion and in treating chronic AF, especially in elderly patients.

Adult↗
PubMed1995

Frequency of "optimal anticoagulation" for acute myocardial infarction after thrombolysis with front-loaded recombinant tissue-type plasminogen activator and conjunctive therapy with recombinant hirudin (HBW 023). ALKK Study Group.

This retrospective analysis reviewed 183 patients with acute myocardial infarction who were given front-loaded recombinant tissue-type plasminogen activator (rt-PA) and r-hirudin (HBW 023) in 1 of 4 dose groups (bolus dose of 0.07, 0.1, 0.2, or 0.4 mg/kg, followed by an infusion of 0.05, 0.06, 0.1, or 0.15 mg/kg/hour over 48 hours). Activated partial thromboplastin time (aPTT) levels were determined at baseline and at 4, 8, 12, 16, 20, 24, 32, 40, and 48 hours. Of the 178 patients with r-hirudin treatment for > or = 12 hours, anticoagulation was optimal in 55.1% (all aPTTs > 2 x baseline), suboptimal in 33.7% (lowest aPTT > 1.5 but < 2 x baseline), and inadequate in 11.2% (> or = 1 aPTT but < 1.5 x baseline). Optimal anticoagulation was observed more frequently in the higher dose groups (dose 1, 15%; dose 2, 44.4%; dose 3, 63.4%; dose 4, 73.4%; p for trend < 0.0001). Patency (according to Thrombolysis in Myocardial Infarction trial grade 2 or 3) of the infarct artery after 36 to 48 hours was higher in the group with optimal anticoagulation compared with those with suboptimal or inadequate anticoagulation: 97.9%, 88.4%, and 85%, respectively (p = 0.03 optimal vs suboptimal or inadequate anticoagulation). In conclusion, r-hirudin in a dose of 0.1 or 0.15 mg/kg/hour achieves an optimal anticoagulation in about 63% or 74% of patients, which is associated with an enhanced patency 24 to 48 hours after rt-PA. A subsequent study revealed that this effective anticoagulation may be accompanied by an increased risk of severe bleeding complications after thrombolysis.

Adult↗
PubMed1994

Frequency of achieving optimal reperfusion with thrombolysis in acute myocardial infarction (analysis of four German multicenter studies).

Patients from 4 German multicenter studies on thrombolysis in acute myocardial infarction (AMI) were retrospectively evaluated to assess the incidence of optimal reperfusion, defined as a completely perfused infarct vessel after 90 minutes, without subsequent death or reinfarction, and without reocclusion or deterioration of flow in control angiograms. Of 907 patients with a 90-minute angiogram, 75% had an open infarct vessel by conventional definition (perfusion grade 2 or 3 according to the criteria of the Thrombolysis in Myocardial Infarction [TIMI] study). However, only 62% had TIMI grade 3 complete perfusion. Of the 561 patients with such primary treatment success, 106 (19%) had secondary treatment failure by death, reinfarction, or subtotal or total reocclusion of the infarct vessel. In a subset of 668 patients with a first angiogram after 60 minutes, conventional patency was 70%, complete perfusion 51%, and an optimal perfusion result was achieved in only 42%. The efficacy of thrombolysis in AMI is substantially overestimated by conventional 90-minute patency rates.

Adult↗
PubMed1994

[Analysis of parameters for calculating the intraocular lens].

We analysed the parameters used to calculate IOL power. The results suggest systematical errors in measuring axial length as well as in measuring corneal refractive power. For improving IOL calculation, however, it would in first place be necessary, to improve reproducibility of the measurements.

Humans↗
PubMed1992

Improved thrombolysis in acute myocardial infarction with front-loaded administration of alteplase: results of the rt-PA-APSAC patency study (TAPS)

Thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) and anisoylated plasminogen streptokinase activator (APSAC) in myocardial infarction has been proved to reduce mortality. A new front-loaded infusion regimen of 100 mg of rt-PA with an initial bolus dose of 15 mg followed by an infusion of 50 mg over 30 min and 35 mg over 60 min has been reported to yield higher patency rates than those achieved with standard regimens of thrombolytic treatment. The effects of this front-loaded administration of rt-PA versus those obtained with APSAC on early patency and reocclusion of infarct-related coronary arteries were investigated in a randomized multicenter trial in 421 patients with acute myocardial infarction. Coronary angiography 90 min after the start of treatment revealed a patent infarct-related artery (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3) in 84.4% of 199 patients given rt-PA versus 70.3% of 202 patients given APSAC (p = 0.0007). Early reocclusion within 24 to 48 h was documented in 10.3% of 174 patients given rt-PA versus 2.5% of 163 patients given APSAC. Late reocclusion within 21 days was observed in 2.6% of 152 patients given rt-PA versus 6.3% of 159 patients given APSAC. There were 5 in-hospital deaths (2.4%) in the rt-PA group and 17 deaths (8.1%) in the APSAC group (p = 0.0095). The reinfarction rate was 3.8% and 4.8%, respectively. Peak serum creatine kinase and left ventricular ejection fraction at follow-up angiography were essentially identical in both treatment groups. There were more bleeding complications after APSAC (45% vs. 31%, p = 0.0019).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Theoretical and practical vision quality with diffractive-multifocal lenses].

I investigated the discrimination of objects with diffractive bifocal contactlenses, when objects in different distances are presented simultaneously. Computer assisted considerations suggested an impairment of discrimination as compared to monofocal correction for far as well as for near. The theoretical loss of image information has been shown to occur also in a visual test with steric arrangement of object points. However, the experiments suggested, that this kinds of visual quality impairment does not play a dominant role in the qualification of diffractive bifocals, since a rather sophisticated procedure was needed to demonstrate the expected effect.

Computer Simulation↗
PubMed1989

Improved thrombolysis with a modified dose regimen of recombinant tissue-type plasminogen activator.

To improve further the patency rate of infarct-related coronary arteries, the following accelerated dosage regimen of recombinant tissue-type plasminogen activator (rt-PA) was administered to 80 patients with acute myocardial infarction of less than or equal to 6 h duration: 15 mg intravenous bolus, 50 mg infusion over 30 min and 35 mg infusion over the following 60 min. After coronary angiography at 90 min coronary angioplasty was performed in 16 patients and additional thrombolysis in 3 patients. Six patients were not included in the final angiographic analysis, mostly because of borderline ST segment elevations, in order to avoid overestimation of the efficacy of this dose regimen. Four of these had a patent infarct artery; no early angiogram was performed on two. Sixty minutes after the start of infusion, 54 (74%) of 73 patients had a patent infarct-related artery (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3) as did 67 (91%) of 74 patients at 90 min. At 24 h, 61 (92.4%) of 66 patients showed a patent infarct artery. Recurrent myocardial ischemia was noted in 12 patients, 7 (9.4%) of whom experienced reinfarction during the hospital stay. Minor local bleeding complications were observed in 14 patients (17.5%). There were four in-hospital cardiac deaths; one patient who underwent additional thrombolysis for recurrent ischemia died from bleeding complications. These results show that a rapid infusion of 100 mg of rt-PA over 90 min yields a high early patency rate of the infarct-related artery without an increase in reocclusion rate and adverse reactions.

Adult↗
PubMed1988

Intravenous recombinant tissue plasminogen activator (rt-PA) and urokinase in acute myocardial infarction: results of the German Activator Urokinase Study (GAUS).

The effects of recombinant tissue plasminogen activator (rt-PA) and urokinase on patency and early reocclusion of infarct-related coronary arteries were investigated in a single blind, randomized multicenter trial in 246 patients with acute myocardial infarction of less than 6 h duration. Both 70 mg of single chain rt-PA with an initial bolus of 10 mg and 3 million units of urokinase with an initial bolus of 1.5 million units were given intravenously over 90 min. The first angiographic study at the end of the infusion revealed a patent infarct-related artery (Thrombolysis in Myocardial Infarction trial [TIMI] grade 2 or 3) in 69.4% of 121 patients given rt-PA versus 65.8% of 117 patients given urokinase (p = NS). Among patients treated within 3 h from symptom onset a patent infarct-related artery was found in 63.9% of 72 patients given rt-PA versus 70% of 70 patients given urokinase (p = NS). There were five cardiac deaths in each group and one fatal intracranial hemorrhage in the rt-PA group. The in-hospital reinfarction rate was 8.9% versus 13.2% for patients treated with rt-PA and urokinase, respectively. There was no difference in left ventricular function at baseline and follow-up catheterization studies. Both drugs were well tolerated and there was no significant difference in cardiovascular or bleeding complications between the two groups. It is concluded that rt-PA and urokinase in the dosages used provide similar efficacy and safety in the treatment of acute myocardial infarction. Reocclusion during the first 24 h may be less frequent after urokinase treatment.

Adult↗
PubMed1988

[Intravenous infusion of recombinant tissue-type plasminogen activator (rt-PA) and urokinase in acute myocardial infarct: intermediate results of the G.A.U.S. study (German Activator Urokinase Study)].

The effects of recombinant tissue plasminogen activator (rt-PA) and urokinase on patency and early reocclusion of infarct-related coronary arteries were investigated in a single blind, randomised multicenter trial in up to now 125 patients with acute myocardial infarction of less than six hours duration. Both, 70 mg of single-chain rt-PA with an initial bolus of 10 mg, and 3 million U of urokinase with an initial bolus of 1,5 million U were given intravenously over 90 minutes. The first angiogram at the end of the infusion revealed a patent infarct-related artery (TIMI grade 2 or 3) in 68% of 62 patients with rt-PA vs. 63% of 63 patients with urokinase (n.s.). Twenty-four hours later patent infarct-related arteries occurred in the same frequency in the rt-PA group and in the urokinase group (71.5% vs. 74.6%, n.s.), although additional recanalisation procedures in sequence with the first angiography were performed more frequent in the rt-PA group. There were two cardiac deaths in either group. In-hospital reinfarction rate was 9.7% vs. 17.5% for patients treated with rt-PA and urokinase, respectively. Both drugs were well tolerated, no significant difference of cardiovascular or bleeding complications could be observed between the two groups. It is concluded that rt-PA and urokinase in the dosages used provide similar efficiency and safety in the treatment of acute myocardial infarction.

Adult↗
PubMed1984

[Late complications following heart valve replacement].

Patients with cardiac valve replacement require regular follow-up examinations since complications are not infrequent with valve prostheses. All mechanical valves are thrombogenic, only bioprostheses implanted in patients with constant sinus rhythm do not require anticoagulation. One of the most important practical tasks is the exact adjustment of anticoagulant administration in order to achieve prothrombin values of between 15 and 25%. During check-ups the physician has to pay special attention to changes in symptoms and auscultation which might point to dysfunction of the valve. Of special importance is fever of unclear origin since endocarditis of the valve is a very serious complication. The patient must be admitted to hospital at the slightest suspicion of endocarditis.

Endocarditis, Bacterial↗
PubMed1978

Glucagon, insulin, cortisol, and growth hormone levels following major surgery: their relationship to glucose and free fatty acid elevations.

Circulating hormone and substrate levels were measured in 7 patients at regular intervals before, during and after pulmonary surgery. During surgery, cortisol and growth hormone were significantly elevated, pancreatic glucagon was unchanged and insulin was depressed. One and two days after surgery, growth hormone had almost returned to preoperative fasting values, but cortisol, insulin and glucagon levels were significantly increased. The mean insulin:glucagon molar ratio declined from a preoperative fasting value of 3.2 +/- 0.5 (+/- SEM) to 1.7 +/- 0.4 during operation but was within normal limits 1 and 2 days after surgery due to a parallel rise and fall in plasma insulin and glucagon. Plasma glucose was elevated both during operation and for several days thereafter, whereas free fatty acid levels were increased only during operation. Thus, there was no consistent relation between insulin:glucagon ratio or any of the hormone levels and the observed elevations in plasma glucose and free fatty acids. It is concluded that neither any of the hormones assayed nor the insulin:glucagon ratio was the primary determinant of plasma glucose and free fatty acid responses to surgery. Rather, fuel homeostasis appeared to result from the combined effects of glucagon, insulin, growth hormone, cortisol and adrenergic activity.

Adult↗
PubMed1978

Failure of inhibiting corneal graft rejection in rabbits by 5 alpha-androstane-3,17-dione.

Corneal transplantations were performed on both eyes of 19 albino rabbits. For each animal both grafts were taken from one pigmented donor rabbit. In all animals one eye was treated with a 2% 5alpha-androstane-3,17-dione ointment (alphaA) and the other eye with an ointment containing no steroid (6 rabbits) or 2% cortisol (13 rabbits). Our experiments showed that alphaA cannot inhibit the efferent limb of corneal graft rejection as effectively as cortisol. we discuss some histological features of corneal graft rejection and our technique of corneal grafting in rabbits.

Androstanes↗