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J Lubsen

Publications and source records attributed to J Lubsen.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Reliability of blood pressure measurements; comparison of an electronic meter and a mercury manometer in family practice].

The Riva-Rocci indirect method of measuring the blood pressure carries a number of sources of error. A report is presented of a study of the serviceability of an electronic blood pressure meter as compared with the conventional mercury manometer. Seventy-six paired measurements were carried out in patients selected at random using an electronic blood pressure meter and a mercury manometer meeting all Health Council requirements. The systematic error and the incidental error in both measuring procedures were compared. The differences found were so slight as to be negligible in practice. It is concluded that the electronic blood pressure meter in practice constitutes an acceptable substitute for the conventional mercury manometer.

Blood Pressure Determination↗
PubMed1990

Medical management of unstable angina. What have we learned from the randomized trials?

Because of the absence of a generally accepted definition of unstable angina, the clinical context of drug trials for this condition has varied from trial to trial. Early- versus late-entry trials must be distinguished, and the possibility of a modification of effect caused by the nature of drug therapy already given when the patient became unstable or by concomitant treatment in addition to experimental treatment must be taken into account. These factors cannot be overlooked when the results from a limited number of reported trials are pooled together. The largest early-entry trial with a beta-blocker and a calcium antagonist was the Holland Interuniversity Nifedipine/metoprolol Trial (HINT), which enrolled patients with suspected unstable angina diagnosed at coronary care unit admission. HINT results showed that unstable angina cannot be reliably differentiated from evolving myocardial infarction (MI) in this particular context and that there are few early MIs that could have been prevented. In patients who were not already taking a beta-blocker, metoprolol reduced the incidence of acute MI or recurrent ischemia, and there was no benefit of nifedipine. On the other hand, the addition of nifedipine was effective in patients whose conditions became unstable despite maintenance treatment with a beta-blocker. Thus, previous beta-blockade modified the effect of the calcium antagonist studied. Based on evidence from HINT and other trials, it is concluded that beta-blockers should be used as the first-line treatment in patients with unstable angina and that a calcium antagonist should be added when patients remain unstable despite beta-blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1989

Large trials with simple protocols: indications and contraindications.

The design of a clinical trial derives from its objective, which in its turn is dictated by the needs of clinical practice. Therefore, a common condition, a simple treatment, and a simple outcome measure are opportunities rather than design options. The argument that the direction of the net treatment effect can be expected to be similar across patient subgroups is inconsistent with biologic reality, and may misguide interpretation of both individual and pooled trial results. If no data on patient characteristics are recorded, scientific generalization is hampered and there is limited opportunity to learn about mechanisms of action and about specific indications and contraindications. If the treatment influences an intermediary outcome, which is assumed to have a causal role in the disease process that the treatment eventually seeks to influence, the effect on the intermediary outcome is of great importance--for clinical practice is very much centered around this outcome and the effects on intermediary outcomes may serve as an aid in explaining why there is an effect or why not. In conclusion, there are some research questions that may warrant large and simple trials, but many clinically very relevant research questions require a more complex trial design.

Clinical Protocols↗
PubMed1989

Increased serum levels of fibrinogen degradation products due to treatment with recombinant tissue-type plasminogen activator for acute myocardial infarction are related to bleeding complications, but not to coronary patency. European Co-operative Study Groups for rt-PA.

The association of increasing serum levels of fibrinogen degradation products after recombinant tissue-type plasminogen activator (rt-PA) therapy with bleeding and early coronary patency was assessed in 242 patients with acute myocardial infarction. After administration of 5,000 IU heparin, a median of 40 mg (range 35 to 60) of double chain rt-PA was given intravenously in 90 min. Bleeding occurred in 62 patients; in 73% of patients it was observed within the 1st 24 h and 84% of events consisted of hematoma or prolonged bleeding, or both, at puncture sites. Bleeding events occurred 2.12 times as often in patients with serum levels of fibrinogen degradation products greater than 85 mg/liter as in patients with serum levels less than 22 mg/liter (95% confidence interval 1.01 to 4.43). The infarct-related coronary vessel was patent in 65% of patients at 90 min after the start of rt-PA infusion. In patients with high serum levels of fibrin(ogen) degradation products, coronary patency at 90 min after the start of rt-PA infusion was not better (13% less, 95% confidence interval - 33%, 13%) than in patients with low serum levels. This uncoupling of thrombolytic effect in terms of coronary patency and systemic fibrinogenolysis confirms the experimentally demonstrated fibrin specificity of double chain rt-PA in human subjects. Because fibrin specificity of single chain rt-PA is at least similar to that of double chain rt-PA, the observations in this analysis most likely hold also for single chain rt-PA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Multicentre European trials: their design, execution and relevance.

Multicentre randomized clinical trials in Europe over the past decade have made a major contribution to the practice of cardiology and will increasingly do so when the Single Europe Act becomes a fact of life in 1992. The arguments for independent scientifically based research organizations and their role in the area of coronary artery disease are outlined. These include cost-benefit considerations, the science of clinical trials, data acquisition techniques and data management requirements. The role of the pharmaceutical industry in relation to the investigator-trialist is discussed. A critique of the current fashion 'Big is beautiful', with arguments against 'simplicity' and 'large size' and the need for 'credibility' is provided. Applicability of data from trials and their economic usefulness and validity in terms of sound pathophysiological hypotheses are also discussed and illustrated by using the CABRI trial as an example.

Angioplasty, Balloon, Coronary↗
PubMed1988

Monitoring methods, considerations, and statement of the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS) Ethical Review Committee.

The Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS) was terminated prematurely when an independent Ethical Review Committee concluded, on the basis of interim analyses, that continuation would not be advisable on either ethical or scientific grounds. Among 124 patients treated with enalapril and 120 randomized to placebo, 6-month mortality rates were 27 and 48%, respectively. The 2 groups were found to be well balanced with regard to baseline clinical characteristics, and a consistent treatment effect was evident among subgroups. Furthermore, the difference favoring enalapril was found to have been present since the beginning of the study and was consistent over time. Based on these findings, the study was halted on December 14, 1986.

Chronic Disease↗
PubMed1988

Thrombolysis with tissue plasminogen activator in acute myocardial infarction: no additional benefit from immediate percutaneous coronary angioplasty.

A randomised trial of 367 patients with acute myocardial infarction was performed to determine whether an invasive strategy combining thrombolysis with recombinant tissue-type plasminogen activator (rTPA), heparin, and acetylsalicylic acid, and immediate percutaneous transluminal coronary angioplasty (PTCA) would be superior to a noninvasive strategy with the same medical treatment but without immediate angiography and PTCA. Intravenous infusion of 100 mg rTPA was started within 5 h after onset of symptoms (median 156 min). Angiography was performed 6-165 min later in 180 out of 183 patients allocated to the invasive strategy; 184 patients were allocated to the non-invasive strategy. Immediate PTCA reduced the percentage stenosis of the infarct-related segment, but this was offset by a high rate of transient (16%) and sustained (7%) reocclusion during the procedure and recurrent ischaemia during the first 24 h (17%). The clinical course was more favourable after non-invasive therapy, with a lower incidence of recurrent ischaemia within 24 h (3%), bleeding complications, hypotension, and ventricular fibrillation. Mortality at 14 days was lower in patients allocated to non-invasive treatment (3%) than in the group allocated to invasive treatment (7%). No difference between the treatment groups was observed in infarct size estimated from myocardial release of alpha-hydroxybutyrate dehydrogenase or in left ventricular ejection fraction after 10-22 days. Since immediate PTCA does not provide additional benefit there seems to be no need for immediate angiography and PTCA in patients with acute myocardial infarction treated with rTPA.

Adult↗
PubMed1988

Coronary patency after intravenous infusion of recombinant tissue-type plasminogen activator in acute myocardial infarction.

The relation between coronary patency after infusion of recombinant tissue-type plasminogen activator (rt-PA) and clinical and laboratory findings was assessed in patients with acute myocardial infarction. This study focused primarily on information available early in the hospitalization phase. Data were available for 243 patients who received the full dose of rt-PA and who had assessable coronary angiograms 90 min after the start of the intravenous infusion. The infarct-related vessel was scored by an independent assessment committee as being patent in 65% of patients. The left anterior descending coronary artery was involved in 53% of patients, and proximal localization of the infarct-related vessel occurred in 65%. In the majority of patients (85%), the infusion was started within 4 h of the acute event. Neither the angiographic location of the infarct-related vessel nor electrocardiographic evidence of infarct severity or location appeared to have a bearing on thrombolysis with rt-PA. Multivariate logistic regression analysis identified three independent predictors of coronary patency: hematocrit 43 to 47%, blood plasminogen level greater than or equal to 90% of normal and serum alkaline phosphatase greater than or equal to 82% of the local upper normal limit. In addition, the use of intravenous nitrates suggests a positive association with patency.

Aged↗
PubMed1988

Serum potassium values in relation to the use of diuretics in patients with unstable angina pectoris.

Transient hypokalaemia may occur in acutely ill patients and is associated with an increased incidence of life-threatening arrhythmias. Therefore, we performed a retrospective analysis of the serum potassium values of 538 patients with unstable angina included in the Holland Interuniversity Nifedipine/metoprolol Trial in relation to the use of diuretics. On admission, 113 of these patients used diuretics. Potassium sparing diuretics had been used in 65 patients (group A) and non-potassium sparing diuretics in 48 patients (group B). From the 425 patients not on diuretics a random sample of 56 (group C) was drawn. Blood samples were taken routinely on admission to the coronary care unit. The serum potassium values found for group A, B and C were 3.77 +/- 0.55, 3.44 +/- 0.69 and 4.14 +/- 0.48, respectively, and the prevalence of hypokalaemia (less than 3.6 mmol) 40, 65 and 14% respectively. Rate ratio [95% confidence interval (CI)] for hypokalaemia when compared to group C was 2.6 (1.2-5.6) for group A and 4.9 (2.4-10.1) for group B. The prevalence of hypokalaemia was higher for women than for men (rate ratio, 95% CI: 1.4, 0.9-2.2). Patients already on beta-blocker therapy showed a 10% lower prevalence of hypokalaemia (rate ratio, 95% CI: 0.7, 0.5-1.1). These data were compared with serum potassium values of 104 patients with stable angina, who reported to the outpatient clinic. These patients were also divided into three groups according to the use of diuretics. Only in 15% of the patients using non-potassium sparing diuretics was hypokalaemia observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1988

Early treatment of unstable angina with nifedipine and metoprolol--the HINT trial.

A multicenter, double-blind, placebo-controlled, randomized trial of nifedipine, metoprolol, and their combination was conducted in a group of 338 patients with unstable angina not pretreated with a beta-blocker and of nifedipine in 177 patients who were. The main outcome event was recurrent ischemia or myocardial infarction within 48 h. Trial medication effects were expressed as ratios of event rates relative to placebo. In patients not pretreated with a beta-blocker, the event rate ratios with associated 95% confidence intervals were 1.15 (0.83, 1.64) for nifedipine, 0.76 (0.49, 1.16) for metoprolol, and 0.80 (0.53, 1.19) for the combination. In patients already on a beta-blocker, the addition of nifedipine was beneficial [rate ratio of 0.68 (0.47, 0.97)]. Equal numbers of patients developed myocardial infarction and reversible ischemia. Most infarctions occurred early, within 6 h of randomization. These results suggest that in patients not on prior beta-blockade, metoprolol has a beneficial short-term effect on unstable angina, the fixed combination with nifedipine provides no further gain, and nifedipine may be counterproductive. On the other hand, the addition of nifedipine to existing beta-blockade when the patient becomes unstable seems beneficial. These findings accord with those of other trials on unstable angina.

Aged↗
PubMed1988

Enzyme tests in the evaluation of thrombolysis in acute myocardial infarction.

The activity of alpha-hydroxybutyrate dehydrogenase, creatine kinase, creatine kinase MB and aspartate aminotransferase was measured on serial plasma samples from patients with acute myocardial infarction. The study was part of a multicentre randomised trial of the effect of thrombolytic treatment in the acute phase of acute myocardial infarction. The applicability and comparability of enzyme tests for the estimation of myocardial injury were studied in 76 control patients and 74 patients treated with streptokinase. Treatment with streptokinase caused a considerable acceleration of enzyme release after acute myocardial infarction, both in patients with persistent coronary occlusion and in those with successful reperfusion. But this changed pattern of enzyme release did not affect the rate of enzyme elimination from plasma or the released proportions of different enzymes. Thus the assessment of infarct size by measurement of these enzyme activities can also be applied to patients treated with streptokinase. Moreover, the enzymes measured in the present study are all equally valid markers of myocardial injury.

Aspartate Aminotransferases↗
PubMed1988

Cost benefit analysis of early thrombolytic treatment with intracoronary streptokinase. Twelve month follow up report of the randomised multicentre trial conducted by the Interuniversity Cardiology Institute of The Netherlands.

The costs and benefits of early thrombolytic treatment with intracoronary streptokinase in acute myocardial infarction were compared in a randomised trial. All hospital admissions were recorded and the functional class was assessed at visits to the outpatient clinic during a 12 month follow up of 269 patients allocated to thrombolytic treatment and of 264 allocated to conventional treatment. Mean survival during the first year was calculated for patients with inferior and with anterior infarction and adjusted for impaired quality of life in cases where there were symptoms or hospital admission. In patients with inferior infarction mean survival was 337 days (out of a total follow up of 365 days) for patients allocated to thrombolytic treatment and 327 days for controls. Quality adjusted survival was seven days longer in the thrombolysis group (307 vs 300 days in controls). In patients with anterior infarction mean survival was significantly longer (35 days) in the thrombolysis group than in the control group as was quality adjusted survival (38 days) (304 vs 266 days in controls). The gain in life expectancy with thrombolytic treatment was 0.7 years for patients with inferior infarction, 2.4 years for patients with anterior infarction, and 3.6 years for the subset of patients with large anterior infarction who were admitted within two hours of the onset of symptoms. The costs of medical treatment, including medication, hospital stay, cardiac catheterisation, coronary angioplasty, and bypass surgery, in the first year follow up were higher inpatients allocated to thrombolytic treatment (an additional cost ofDfl 7000 in inferior and Dfl 9000in anterior infarction (1 pounds sterling approximately Dfl 3.3.)) than in conventionally treated patients. The additional costs per year of life gained were Dfl 10 000 in inferior infarction, Dfl 3 800 in anterior infarction, and only Dfl 1 900 in patients with large anterior infarction admitted within two hours of onset of symptoms. Intracoronary thrombolysis can be recommended as a cost effective treatment in patients with extensive anteroseptal infarction.

Clinical Trials as Topic↗
PubMed1988

Assessment of immediate and long-term functional results of percutaneous transluminal coronary angioplasty.

Assessment of the functional significance of coronary artery lesions during cardiac catheterization has recently become possible by calculating coronary flow reserve from both myocardial contrast appearance time and density in the resting and hyperemic states determined from digitized coronary cineangiograms. However, the interobserver and intraobserver variabilities, as well as the short-, medium-, and long-term variabilities of the coronary flow reserve measurements, have to be established before this technique becomes an acceptable means of assessing the immediate and long-term functional results of revascularization procedures such as percutaneous transluminal coronary angioplasty (PTCA). Variability was defined as the mean difference and standard deviation of the difference between duplicate determinations of coronary flow reserve. The intraobserver variability (mean difference +/- SD) in the measurement of coronary flow reserve was -0.01 +/- 0.07. Interobserver variability by two observers was +0.08 +/- 0.52. Short-term variability based on the analysis of two coronary cineangiograms taken 5 minutes apart was -0.02 +/- 0.26. Medium-term variability (coronary cineangiographies repeated 1-3 hours apart) was found to be -0.06 +/- 0.52. Long-term variability (coronary cineangiographies repeated 3-5 months apart) was 0.11 +/- 0.63. Having established the reproducibility of this radiographic method, we studied the prospective changes in coronary flow reserve in 25 patients undergoing PTCA for single vessel coronary artery disease. Coronary flow reserve measurements and quantitative coronary cineangiography were performed before, immediately after, and 3-5 months after PTCA. PTCA resulted in an immediate increase in coronary flow reserve from 1 +/- 0.3 to 2.3 +/- 0.6 with a concomitant increase in obstruction area from 0.9 +/- 0.3 to 3.3 +/- 0.7 mm2. Nine of the 25 patients developed restenosis defined as a diameter stenosis greater than 50% at follow-up. The other 16 patients had a coronary flow reserve of 3.3 +/- 0.6, which was measured 3-5 months after PTCA. Coronary flow reserve measurement from digitized coronary cineangiograms is a reproducible method for the assessment of the physiological importance of coronary artery obstructions. Short-, medium-, and long-term investigations of the functional results of interventions such as pharmacological therapy or revascularization can be performed reliably with this technique.

Adult↗