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R W Koster

Publications and source records attributed to R W Koster.

At least 19 recordsLinked to original sources
PubMed2000

Diagnostic accuracy of myoglobin concentration for the early diagnosis of acute myocardial infarction.

STUDY OBJECTIVE: We evaluated the diagnostic accuracy of myoglobin determination for the early diagnosis of acute myocardial infarction (AMI). METHODS: Consecutive patients with chest pain were included in the study. Receiver operating characteristic (ROC) analysis was used to assess optimal timing of blood sampling and cutoff values. RESULTS: A total of 309 patients were included, of whom 162 patients had a diagnosis of AMI. ROC analysis revealed that the diagnostic accuracy of myoglobin concentration as indicated by the area under the ROC curve (AUC) increased significantly from 3 (0.89+/-0.026) and 4 hours (0.93+/-0.019) to 5 hours after onset of symptoms (0. 96+/-0.014; P=.0040 and.035, respectively). At 5 hours (the earliest time point with maximal AUC), sensitivity was 87% and specificity was 97% using a myoglobin cutoff value of 90 microg/L. With a myoglobin cutoff value of 50 microg/L, sensitivity was 95% (95% confidence interval 90% to 98%), but specificity was 86% (95% confidence interval 80% to 93%). CONCLUSION: Myoglobin has maximal diagnostic accuracy for the diagnosis of AMI at 5 hours after the onset of symptoms, using a cutoff value of 50 microg/L. In combination with the measurement of other biochemical markers, myoglobin determination could be particularly useful for triage of patients with AMI at an early stage.

Adolescent↗
PubMed1999

In-hospital cardiopulmonary resuscitation: prearrest morbidity and outcome.

BACKGROUND: Considerations about the application of cardiopulmonary resuscitation (CPR) should include the expected probability of survival. The survival probability after CPR may be more accurately estimated by the occurrence in time of the prearrest morbidity of patients. OBJECTIVE: To identify risk factors for poor survival after CPR in relation to the dynamics of prearrest morbidity. METHODS: Medical records of CPR patients were reviewed. Prearrest morbidity was established by categorizing the medical diagnoses according to 3 functional time frames: before hospital admission, on hospital admission, and during hospital admission. Indicators of poor survival after CPR were identified through a logistic regression model. RESULTS: Included in the study were 553 CPR patients with a median age of 68 years (age range, 18-98 years); 21.7% survived to hospital discharge. Independent indicators of poor outcome were an age of 70 years or older (odds ratio [OR]=0.6, 95% confidence interval [CI]=0.4-0.9), stroke (OR=0.3, 95% CI=0.1-0.7) or renal failure (OR=0.3, 95% CI=0.1-0.8) before hospital admission, and congestive heart failure during hospital admission (OR=0.4, 95% CI=0.2-0.9). Indicators of good survival were angina pectoris before hospital admission (OR=2.1, 95% CI=1.3-.3.3) or ventricular dysrhythmia as the diagnosis on hospital admission (OR=11.0, 95% CI=4.1-33.7). Based on a logistic regression model, 17.4% of our CPR patients (n= 96) were identified as having a high risk for a poor outcome (< 10% survival). CONCLUSIONS: Time of prearrest morbidity has a prognostic value for survival after CPR. Patients at risk for poor survival can be identified on or during hospital admission, but the reliability and validity of the model needs further research. Although decisions will not be made by the model, its information can be useful for physicians in discussions about patient prognoses and to make decisions about CPR with more confidence.

Adult↗
PubMed1999

[Defibrillation with an automatic external defibrillator outside the hospital: a life-saving, but restricted treatment?].

Application of the automatic external defibrillator can improve the chance of success during resuscitation of out-of-hospital cardiac arrest, because lay persons can defibrillate awaiting the arrival of the ambulance. Defibrillation is mentioned in the Dutch Individual Health Care Professionals Act as a precluded action. Defibrillation with an automatic external defibrillator should be excluded from the list of precluded actions, because application is almost 100% safe and because the subject is not within the scope of the law which is restricted to professional activities and non-emergency actions. Defibrillation with an automatic external defibrillator is acceptable.

Electric Countershock↗
PubMed1999

Quality of survival after cardiopulmonary resuscitation.

BACKGROUND: Outcome of cardiopulmonary resuscitation (CPR) can be poor, in terms of life expectancy and quality of life. OBJECTIVES: To determine the impact of patient characteristics before, during, and after CPR on these outcomes, and to compare results of the quality-of-life assessment with published studies. METHODS: In a cohort study, we assessed by formal instruments the quality of life, cognitive functioning, depression, and level of dependence of survivors after inhospital CPR. Follow-up was at least 3 months after discharge from the hospital (tertiary care center). RESULTS: Of 827 resuscitated patients, 12% (n = 101) survived to follow-up. Of the survivors, 89% participated in the study. Most survivors were independent in daily life (75%), 17% were cognitively impaired, and 16% had depressive symptoms. Multivariate regression analysis showed that quality of life and cognitive function were determined by 2 factors known before CPR-the reason for admission and age. Factors during and after resuscitation, such as prolonged cardiac arrest and coma, did not significantly determine the quality of life or cognitive functioning of survivors. The quality of life of our CPR survivors was worse compared with a reference group of elderly individuals, but better than that of a reference group of patients with stroke. The quality of life did not importantly differ between the compared studies of CPR survivors. CONCLUSIONS: Cardiopulmonary resuscitation is frequently unsuccessful, but if survival is achieved, a relatively good quality of life can be expected. Quality of life after CPR is mostly determined by factors known before CPR. These findings may be helpful in informing patients about the outcomes of CPR.

Activities of Daily Living↗
PubMed1999

Independent prognostic value of C-reactive protein and troponin I in patients with unstable angina or non-Q-wave myocardial infarction.

OBJECTIVES: Elevated concentrations of C-reactive protein (CRP), a non-specific acute phase reactant, and troponin I (TnI), a cardiac-specific marker of myocardial damage, have been found to be associated with a higher risk for cardiac events in patients with an acute coronary syndrome. We evaluated CRP alone and in combination with TnI for predicting the incidence of major cardiac complications within 6 months in patients with unstable angina or non-Q-wave infarction (NQMI). METHODS: CRP and TnI was measured on admission in patients with unstable angina or NQMI, but results were kept blinded. Patients were treated according to a conservative management strategy, and the incidence of major cardiac events within 6 months was assessed. RESULTS: An abnormal CRP (> 5 mg/l) and an abnormal TnI (> 0.4 microgram/l) were more frequent in patients that suffered a major cardiac event (CRP: 93 vs. 35%, P < 0.0001; TnI: 73 vs. 26%, P < 0.001). The incidence of major cardiac events was higher in patients with an abnormal CRP than in patients with a normal CRP, both when TnI was abnormal (42 vs. 4.5%, P = 0.003) and when TnI was normal (11 vs. 0%, P = 0.014). Mean event-free survival was excellent in patients with both a normal CRP and TnI, whereas survival was poorest in patients with both an abnormal CRP and TnI (121 +/- 16 vs. 180 days, P < 0.0001). CONCLUSIONS: An abnormal CRP on admission in patients with unstable angina or NQMI is associated with increased incidence of major cardiac events within 6 months, both in patients with normal and abnormal TnI. CRP and TnI have independent and additive prognostic value in this patient group, and the combination may be useful for early risk stratification.

Aged↗
PubMed1999

Ruling out acute myocardial infarction early with two serial creatine kinase-MBmass determinations.

AIMS: We studied the diagnostic value for acute myocardial infarction of serial creatine kinase-MBmass measurements on admission and at 7 h after the onset of symptoms. METHODS AND RESULTS: Patients presenting to our chest pain unit with symptoms of <5-h duration were eligible. Patients were kept under observation at least until 12 h after onset of symptoms. Blood samples were drawn on admission and 7 and 10 h after onset of symptoms. Creatine kinase-MBmass>7.0 microg x 1(-1) (upper reference limit for acute myocardial infarction), or an increase >2.0 microg x 1(-1) (reference change value) between admission and at 7 h was considered abnormal. Of a total of 470 patients, 248 patients had acute myocardial infarction: 100 out of the 248 patients had a single creatine kinase-MBmass>7.0 microg x 1(-1) on admission (sensitivity 40%, 95% CI:34-46%), 234/248 patients at 7 h (sensitivity 94%, 95% CI:91-97%), and 240/248 at 10 h (sensitivity 97%, 95% CI:94-99%). At 7 h, 246/248 patients had either a single creatine kinase-MB >7.0 microg x 1(-1) or a significant increase between admission and 7 h (sensitivity 99%, 95% CI:98-100%). Of 222 patients without acute myocardial infarction, 214 had a normal serial creatine kinase-MBmass (specificity 96%, 95% CI:93-98%). CONCLUSION: In patients with symptoms of <5-h duration, acute myocardial infarction can be ruled out using serial creatine kinase-MBmass taken on admission and at 7 h.

Adult↗
PubMed1999

Cardiovascular disease in the Netherlands, 1975 to 1995: decline in mortality, but increasing numbers of patients with chronic conditions.

OBJECTIVE: To examine the relation between trends over time in mortality and hospital morbidity caused by various cardiovascular diseases in the Netherlands. DESIGN: Trend analysis by Poisson regression of national data on mortality and hospital admissions from 1975 to 1995. SUBJECTS: The Dutch population. RESULTS: All cardiovascular diseases combined were responsible for 39% of all deaths and 16% of all hospital admissions in 1995. From 1975 to 1995, age adjusted cardiovascular mortality declined by an annual change of -2.0% (95% confidence intervals (CI) -2.1% to -1.9%), while in the same period age adjusted discharge rates increased annually by 1. 3% (95% CI 1.1% to 1.5%). Around 60% of the gain in life expectancy in this period was related to lower cardiovascular mortality. For mortality, major reductions were seen in coronary heart disease (annual change -2.9%) and in stroke (-2.1%), whereas the increase in hospital admissions was mainly caused by chronic manifestations of coronary heart disease (5.1%), heart failure (2.1%), and diseases of the arteries (1.8%). In recent years, the gap between men and women at risk of dying from coronary heart disease became smaller for those aged </= 65 years. CONCLUSIONS: Our findings of a decrease in cardiovascular mortality and an increase in admission rates for chronic conditions such as heart failure, chronic coronary syndromes, and diseases of the arteries, support the hypothesis that the longer survival of many patients with heart diseases is leading to a growing pool of patients at increased risk for subsequent cardiovascular complications in Western countries.

Adolescent↗
PubMed1998

[Early exclusion of ischemic myocardial damage made possible by new biochemical cardiac markers].

New immunochemical assay methods for the cardiac markers creatine kinase (CK) MB mass, myoglobin, troponin T (TnT), troponin I (TnI), fatty acid binding protein (FABP) necessitate re-evaluation of their usefulness in the early diagnosis of myocardial damage. Cardiac markers play an important part in the exclusion of myocardial damage in patients with chest pain and an inconclusive ECG at admission. A serial CK-MB mass determination is particularly suitable for this exclusion of myocardial damage. The sensitivity of TnT shortly after an infarction is comparable with that of CK-MB mass; a single determination on admission is insufficient. The marker myoglobin is of limited value owing to the brief duration of myoglobin rise and insufficient heart specificity. An increased TnT or TnI value in patients with unstable angina pectoris is a prognostically negative sign. It is still not clear how this prognosis can be improved. A negative troponin finding appears not to exclude early complications. The department of Emergency Cardiac Care of the Academic Medical Centre, Amsterdam, the Netherlands, currently prefers the serial measurement of the CK-MB mass, in the future possibly to be supplemented by a troponin determination.

Angina Pectoris↗
PubMed1998

Effects of liver blood flow on the pharmacokinetics of tissue-type plasminogen activator (alteplase) during thrombolysis in patients with acute myocardial infarction.

BACKGROUND: The removal of recombinant tissue-type plasminogen activator (rt-PA; alteplase) by the liver is so rapid that liver blood flow becomes rate determining for its clearance. In patients with myocardial infarction changes in liver blood flow may result from impaired cardiac performance or drug treatment. OBJECTIVE: To estimate the effect of variations in liver blood flow on t-PA plasma concentrations during thrombolytic therapy. METHODS: Fifteen patients with acute myocardial infarction were investigated in an open single-center study at the coronary care unit of University Hospital Leiden. Patients received thrombolytic treatment with 100 mg rt-PA over 3 hours. Liver blood flow was estimated by indocyanine green clearance and by Doppler echocardiography. Concentrations of t-PA antigen, t-PA activity, indocyanine green, alpha 2-antiplasmin, fibrinogen, and fibrin and fibrinogen degradation products were measured. RESULTS: Indocyanine green clearance and clearance of both t-PA antigen (r = 0.78; p < 0:01) and t-PA activity (r = 0.54; p < 0.05) were significantly related. Significant associations between t-PA antigen and fibrin and fibrinogen degradation products and between t-PA antigen and alpha 2-antiplasmin were also found. CONCLUSIONS: The liver blood flow of patients with myocardial infarction is inversely correlated with plasma concentrations of t-PA. In patients with severely impaired liver blood flow and heart failure, high t-PA plasma concentrations may occur if standard doses are given. This finding could contribute to optimization of the dosage of t-PA in certain patient groups.

Aged↗
PubMed1998

Out-of-hospital cardiac arrests in Amsterdam and its surrounding areas: results from the Amsterdam resuscitation study (ARREST) in 'Utstein' style.

The purpose of this study was to describe the chain of survival in Amsterdam and its surroundings and to suggest areas for improvement. To ensure accurate data, collection was made by research personnel during the resuscitation, according to the Utstein recommendations. Between June 1, 1995 and August 1, 1997 all consecutive cardiac arrests were registered. Patient characteristics, resuscitation characteristics and time intervals were analyzed in relation to survival. From the 1046 arrests with a cardiac etiology and where resuscitation was attempted, 918 cases were not witnessed by EMS personnel. The analysis focussed on these 918 patients of whom 686 (75%) died during resuscitation, 148 (16%) died during hospital admission and 84 patients (9%) survived to hospital discharge. Patient and resuscitation characteristics associated with survival were: age, VF as initial rhythm, witnessed arrest and bystander CPR. EMS arrival time was significantly shorter for survivors (median 9 min) compared to non-survivors (median 11 min). In 151 cases the police was also alerted and arrived 5 min (median) earlier than EMS personnel. Using the OPC/CPC good functional health was observed in 50% of the survivors and moderate performance in 29%. All links in the chain of survival must be strengthened, but equipping the police with semi-automatic defibrillators may be the most useful intervention to improve survival.

Adolescent↗
PubMed1998

Clinical evaluation of the CARDIAC STATus, a rapid immunochromatographic assay for simultaneous detection of elevated concentrations of CK-MB and myoglobin in whole blood.

We studied the performance of the CARDIAC STATus, a new rapid, easy to perform qualitative whole blood bedside test for detection of elevated CK-MB and myoglobin in the emergency room. Blood samples from 182 consecutive patients with chest pain were drawn on admission and at five and seven hours after the onset of symptoms. The CARDIAC STATus tests were performed by coronary care unit nurses and, independently, by a trained laboratory technician. The results were compared with quantitative assays for CK-MB mass and myoglobin. At the end of the study, a second test series using a new lot number of cartridges was performed on the same blood samples because of possible elution buffer contamination. Nurses produced more false negative results than the technician (CK-MB 43 vs. 27 %, p=0.01, myoglobin 31 vs. 13%, p<0.0001), but the technician produced more false positive myoglobin results (9.3 vs. 5.5%, p=0.0001). In the second test series, the nurses produced significantly fewer false negative tests both for CK-MB (19%, p<0.0001) and myoglobin (13%, p=0.0002). The false negative rate for the technician was not different between the first and the second test series. The CARDIAC STATus yields a substantial number of false negative results both for CK-MB and myoglobin when compared to a quantitative assay, and therefore at present has limited value for ruling out an acute myocardial infarction.

Creatine Kinase↗
PubMed1997

Diagnostic accuracy of transesophageal echocardiography during cardiopulmonary resuscitation.

OBJECTIVES: We sought to establish the diagnostic accuracy of transesophageal echocardiography (TEE) during cardiopulmonary resuscitation. BACKGROUND: Because of its bedside diagnostic capabilities, excellent cardiac images and lack of interference with resuscitation efforts, TEE is ideally suited to determine the cause of a circulatory arrest that is not due to severe arrhythmia. However, the diagnostic accuracy of TEE during resuscitation is unknown. METHODS: TEE was performed in patients with prolonged circulatory arrest. The TEE diagnoses were compared with diagnoses from autopsy, surgery and clinical follow-up. RESULTS: Of the 48 study patients (29 male, 19 female, mean age +/- SD 61 +/- 20 years), 28 had an in-hospital cardiac arrest and 20 an out-of-hospital onset of arrest. Forty-four patients eventually died; four survived to discharge. The diagnoses made with TEE were cardiac tamponade (n = 6), myocardial infarction (n = 21), pulmonary embolism (n = 6), ruptured aorta (n = 1), aortic dissection (n = 4), papillary muscle rupture (n = 1), other diagnosis (n = 2) and absence of structural cardiac abnormalities (n = 7). A definite diagnosis from a reference standard was available in 31 patients. The TEE diagnosis was confirmed in 27 of the 31-by postmortem examination (n = 19), operation (n = 2), angiography (n = 2) or clinical course (n = 4). In the other four patients the TEE diagnosis proved incorrect by postmortem examination. The sensitivity, specificity and positive predictive value of TEE were 93%, 50% and 87%, respectively. In 15 patients (31%), major therapeutic decisions were based on TEE findings. CONCLUSIONS: TEE can reliably establish the cause of a circulatory arrest during cardiopulmonary resuscitation.

Adult↗
PubMed1997

Critical difference between serial measurements of CK-MB mass to detect myocardial damage.

To assess the critical difference in serial measurements of CK-MBmass and the ability of this critical difference to detect myocardial damage, we studied 110 patients in whom an acute myocardial infarction (AMI) had been ruled out. Blood samples were drawn at 3, 4, 5, 6, 7, 8, 12, 16, 20, and 24 h after onset of symptoms. With a critical difference of 72.6%, an increase of >2.0 microg/L between two CK-MBmass measurements was determined to be significant. Twenty-three of the non-AMI patients had an increase in CK-MBmass >2.0 microg/L, but five of these did not have an abnormal concentration of troponin T (i.e., not >0.1 microg/L). Also among the 110 non-AMI patients, 22 did have an abnormal troponin T value, 18 of whom (82%) also had CK-MBmass increased by >2.0 microg/L. In 20 of the 23 patients with an increase in CK-MBmass >2.0 microg/L, this increase was detected from the values for two samples collected at 5 and 12 h after onset of symptoms. In conclusion, using the critical difference for CK-MBmass defined as an increase >2.0 microg/L detected myocardial damage in patients without AMI.

Adult↗
PubMed1997

The clinical value of lactate dehydrogenase in serum: a quantitative review.

The aim of this article is to describe guidelines for rational use of lactate dehydrogenase and its isoenzymes, in the diagnostic processes and during follow-up, based on a systematic review of relevant literature. Sources of data for this study were English-language scientific publications, obtained from the database of the National Library of Medicine (Medline), concerning the clinical application (diagnosis, monitoring or treatment of disease) of lactate dehydrogenase and lactate dehydrogenase isoenzyme measurements in serum in the following main clinical fields: cardiology, hepatology, haematology and oncology. For acceptance in the present review, studies had to include: a proper definition of the tested patient population, diagnostic criteria, sampling time, sampling frequency, and test characteristics. Estimation of the relation between lactate dehydrogenase or lactate dehydrogenase isoenzymes and specific diseases expressed as sensitivity, specificity, survival or remission rate were extracted. The application of serum lactate dehydrogenase is relevant in the diagnosis of myocardial infarction (late detection), haemolytic anaemia, ovarian dysgerminoma and testicular germ cell tumor. For monitoring the progress of a disease lactate dehydrogenase is relevant in establishing the survival duration and rate in Hodgkin's disease and non-Hodgkin's lymphoma, and in the follow-up of ovarian dysgerminoma. Rational use of lactate dehydrogenase can be achieved when requests for its determination are limited to the above mentioned conditions. No rationale could be found for measuring lactate dehydrogenase isoenzymes.

Animals↗
PubMed1997

Effect of changes in liver blood flow on the pharmacokinetics of saruplase in patients with acute myocardial infarction.

BACKGROUND: The recombinant unglycosylated single chain urokinase-type plasminogen activator saruplase is cleared for a large part by the liver. A large interindividual variation in saruplase concentration is found in acute myocardial infarction (AMI) patients. The variable cardiac performance after an infarct may induce differences in liver blood flow that could explain the concentration diversity. This study was performed to investigate the relation between hepatic blood flow and the pharmacokinetic and pharmacodynamic properties of saruplase. METHODS AND RESULTS: Thirteen AMI patients were enrolled in this open label study. Patients received a bolus injection of 20 mg saruplase followed by a one-hour infusion of 60 mg saruplase. Concurrently 36 mg intravenous indocyanine green (ICG) was given over 1 h to measure hepatic blood flow. Blood samples were taken at regular time intervals to measure plasma levels of urokinase-type plasminogen activator (u-PA) antigen and activity, the two-chain form (tcu-PA) activity, indocyanine green, fibrinogen, fibrin and fibrin degradation products, alpha2-antiplasmin and thrombin antithrombin III complex. A correlation was seen between the clearance of ICG and both those of u-PA antigen (r = 0.62; p <0.05) and u-PA activity (r = 0.57; p <0.05). A negative correlation was seen between the area under the curve of tcu-PA activity and the areas under the effect curves of both fibrinogen and alpha2-antiplasmin (r = -0.84; p <0.01 and r = -0.65; p <0.05). CONCLUSIONS: Liver blood flow is an important determinant of the clearance of u-PA antigen and activity and reduction of flow in patients with heart failure will lead to an increase in plasma concentrations. High plasma concentrations of tcu-PA activity lead to increased systemic fibrinogenolysis. These results may be used to optimize saruplase treatment in patients with impaired cardiac function or after co-medication with drugs that affect liver blood flow.

Aged↗
PubMed1996

Pathogenesis of mitral regurgitation in acute myocardial infarction: importance of changes in left ventricular shape and regional function.

The pathogenesis of mitral regurgitation (MR) was determined by quantitative echocardiography in 188 patients with acute myocardial infarction (AMI) within 48 hours after admission. MR was classified, by using color Doppler, as significant (grades 3 to 4) or trivial (grades 0 to 2). Left ventricular (LV) function (global and regional), volume, and shape, as well as mitral valvular features, were measured and analyzed by stepwise logistic regression. Significant MR occurred in 25 (13%) patients. Univariately, recurrent infarction (p < 0.01), LV dilation (p < 0.001) and sphericity (p < 0.001), inferoposterolateral asynergy (p < 0.001), mitral annular dilatation (p < 0.005), and mitral leaflet restriction (p < 0.05) were associated with significant MR. In regression analysis, only recurrent infarction (odds ratio 5.08), LV sphericity index (odds ratio 1.12), and inferoposterolateral asynergy (odds ratio 6.07) were independently associated with significant MR, whereas none of the mitral valvular features examined had an independent association. In conclusion, changes in LV shape and regional function and not mitral valvular changes are prime determinants of significant MR after AMI.

Aged↗
PubMed1996

Prognostic value of troponin T, myoglobin, and CK-MB mass in patients presenting with chest pain without acute myocardial infarction.

OBJECTIVE: To assess the prognostic value of minor myocardial damage in patients presenting with chest pain without myocardial infarction. DESIGN: The relative risk of suffering a cardiac event in the next six months was assessed in patients with minor myocardial damage assessed by the cardiac markers CK-MB, myoglobin, and troponin T. SETTING: Emergency department of a large university hospital. PATIENTS: In 128 consecutive patients with chest pain, acute myocardial infarction (by WHO criteria) was ruled out; of these, 39 had a rise and fall of one or more markers, indicating minor myocardial damage. The presence of a documented history of coronary artery disease was assessed on admission. RESULTS: 24 patients had a subsequent event (cardiac death, acute myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting) in the next six months. An abnormal troponin T predicted a subsequent event while abnormal CK-MB or myoglobin did not. The relative risk for troponin T was 2.8 (95% confidence interval: 1.0 to 7.9), for myoglobin 1.0 (0.3 to 3.2), and for CK-MB 0.9 (0.2 to 3.4). A documented history of coronary artery disease predicted subsequent events with a relative risk of 3.9 (1.3 to 11.3). CONCLUSIONS: Troponin T was the only marker that predicted future events, but a documented history of coronary artery disease was the best predictor in patients in whom an acute myocardial infarction had been ruled out.

Aged↗