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Biomedical subjects

M L Simoons

Publications and source records attributed to M L Simoons.

At least 253 records · Page 14Linked to original sources

Effects of early intracoronary streptokinase on infarct size estimated from cumulative enzyme release and on enzyme release rate: a randomized trial of 533 patients with acute myocardial infarction.

The effects of early intracoronary streptokinase (SK) on enzymatic infarct size and rate of enzyme release were studied in a randomized multicenter trial. A total of 533 patients with acute myocardial infarction (AMI) were allocated to either the SK treatment group (n = 269) or the conventional (control) treatment group (n = 264). Enzymatic infarct size was represented by the cumulative quantity of alpha-hydroxybutyrate dehydrogenase (HBDH) released by the heart per liter of plasma in the first 72 hours. Rate of enzyme release was represented by the ratio of HBDH quantities released in 24 hours and 72 hours. On an "intention to treat" basis, the SK group had a smaller (by 30%; p = 0.0001) median enzymatic infarct size and a higher (by 35%; p = 0.0001) median rate of enzyme release than the control group. Limitation of infarct size was less apparent in patients treated with intracoronary SK only (25%) than in patients treated with intravenous plus intracoronary SK (34%). Compared to the control group, the enzyme release rate in patients treated with intracoronary SK only was slightly less (34%) than that in patients treated with intravenous plus intracoronary SK (38%). Patients with a patent infarct-related coronary artery at acute angiography had a median infarct size which was 55% (p = 0.0001) smaller than the median infarct size of the control group, and the median rate of enzyme release was 38% (p = 0.001) higher than the median release rate of the control group. Patients with successful recanalization during intracoronary SK infusion had a median infarct size which was 31% (p = 0.002) smaller than the median infarct size of the control group and a median rate of enzyme release which was 42% (p = 0.0001) higher than the median release rate of the control group. Patients with persistent coronary occlusion in spite of thrombolytic therapy had a median infarct size which was 11% (NS) higher than the median infarct size of the control group, although the median rate of enzyme release was still 23% (p = 0.02) higher than the median release rate of the control group. It is concluded that thrombolysis in the early phase of AMI limits infarct size and that intracoronary SK treatment itself accelerates the process of enzyme release from infarcted myocardium, independent of the angiographic result.

Clinical Trials as Topic↗

Relative value of clinical variables, bicycle ergometry, rest radionuclide ventriculography and 24 hour ambulatory electrocardiographic monitoring at discharge to predict 1 year survival after myocardial infarction.

The relative value of predischarge clinical variables, bicycle ergometry, radionuclide ventriculography and 24 hour ambulatory electrocardiographic monitoring for predicting survival during the first year in 351 hospital survivors of acute myocardial infarction was assessed. Discriminant function analysis showed that in patients eligible for stress testing the extent of blood pressure increase during exercise slightly improved the predictive accuracy beyond that of simple clinical variables (history of previous myocardial infarction, persistent heart failure after the acute phase of infarction and use of digitalis at discharge), whereas radionuclide ventriculography and 24 hour electrocardiographic monitoring did not. The predictive value for mortality was 12% with clinical variables alone and 15% with the stress test added. Radionuclide ventriculography and 24 hour electrocardiographic monitoring were slightly additive to clinical information in the whole group of patients independent of the eligibility for stress testing (predictive value for mortality 24% with clinical variables alone and 26% with radionuclide ejection fraction and 24 hour electrocardiographic monitoring added). It is concluded that the appropriate use of simple clinical variables and stress testing is sufficient for risk stratification in postinfarction patients, whereas radionuclide ventriculography and 24 hour electrocardiographic monitoring should be limited to patients not eligible for stress testing.

Aged↗

Early thrombolysis in acute myocardial infarction: limitation of infarct size and improved survival.

The effect of thrombolysis in acute myocardial infarction on infarct size, left ventricular function, clinical course and patient survival was studied in a randomized trial comparing thrombolysis (269 patients) with conventional treatment (264 control patients). All 533 patients were admitted to the coronary care unit within 4 hours after the onset of symptoms related to the infarction. Baseline characteristics were similar in both groups. Informed consent was requested only of patients allocated to thrombolysis; no angiography was performed in 35. The infarct-related artery was patent in 65 patients and occluded in 169. Recanalization was achieved in 133 patients. The median time to angiographic documentation of vessel patency was 200 minutes after the onset of symptoms. The clinical course in the coronary care unit was more favorable after thrombolysis. Infarct size, estimated from myocardial enzyme release, was 30% lower after thrombolysis. In patients admitted within 1 hour after the onset of symptoms the reduction of infarct size was 51%, in those admitted between 1 and 2 hours it was 31% and in those admitted later than 2 hours it was 13%. Left ventricular function measured by radionuclide angiography before hospital discharge was better after thrombolysis (ejection fraction 48 +/- 15%) than in control patients (44 +/- 15%). Similar improvement was observed in patients with a first infarct only (thrombolysis 50 +/- 14%, control subjects 46 +/- 15%), in patients with anterior infarction (thrombolysis 44 +/- 16%, control subjects 35 +/- 14%) and in those with inferior infarction (thrombolysis 52 +/- 12%, control subjects 49 +/- 12%). Similar results were obtained by contrast angiography. Mortality was lower after thrombolysis. After 28 days 16 patients allocated to thrombolysis and 31 control patients had died. One year survival rates were 91 and 84%, respectively. On the other hand, nonfatal reinfarction occurred more frequently after thrombolysis (36 patients) than in control subjects (16 patients). Early thrombolysis by intracoronary streptokinase leads to a smaller infarct size estimated by enzyme release, preserves left ventricular function at the second week and leads to improved 1 year survival.

Aged↗

Preservation of global and regional left ventricular function after early thrombolysis in acute myocardial infarction.

The effect of early myocardial reperfusion (within 4 hours after onset of symptoms) on regional left ventricular function in patients with acute myocardial infarction has been quantitated by analysis of segmental wall motion. Of 533 patients randomized either to conventional coronary care unit therapy or to a reperfusion strategy, in 332 high quality angiograms were obtained 2 to 8 weeks after the onset of myocardial infarction. In those assigned to thrombolytic therapy, angiographic data were also available after acute reperfusion. Analysis on an "intention to treat" basis revealed significant preservation of left ventricular function after thrombolytic therapy (ejection fraction 53%) compared with conventional treatment (ejection fraction 47%). In addition, wall motion analysis showed significant improvement of regional function in the infarct zone in both inferior and anterior infarction. In addition, significant changes occurred in regional function of the remote "noninfarct zone" in the acute as well as the chronic stage. It is concluded that improved regional and global left ventricular function can be achieved with early reperfusion and that this is the likely explanation for the reduction of early and late mortality after thrombolysis observed in this study.

Aged↗

Coronary angioplasty of the unstable angina related vessel in patients with multivessel disease.

This study is a retrospective analysis of the efficacy of percutaneous transluminal coronary angioplasty of the ischaemia-related vessel in patients with unstable angina. Forty-three patients had multivessel disease with dilatation of the ischaemia-related vessel only (group I; partial revascularization) while 111 patients had single vessel disease only (group II; total revascularization). The initial success rate in both groups was identical (88 versus 88%). The need for emergency coronary artery bypass surgery was similar in the two groups (group I 12% versus group II 9%; NS). The total post PTCA myocardial infarction rate (despite urgent CABG) was also similar in the two groups (group I 9% versus group II 10%; NS). The results of electrocardiographic exercise testing and Thallium-201 scintigraphy provide objective evidence for incomplete revascularization in group I. The maximum workload achieved was lower, and the frequency of exercise induced angina, ST-segment depression and reversible perfusion defect was higher than in group II. Moreover, at 6 months follow-up the recurrence rate of angina pectoris rate was higher in group I than in group II (29% versus 16% P less than 0.05). It is concluded that dilatation of the ischaemia related vessel only in patients with unstable angina and multivessel disease is as effective in the management of the acute phase of unstable angina as is dilatation of the ischaemia related vessel in patients with single vessel disease. However, due to only partial revascularization the recurrence rate of angina pectoris is higher.

Adult↗

Long term improvement in global left ventricular function after early thrombolytic treatment in acute myocardial infarction. Report of a randomised multicentre trial of intracoronary streptokinase in acute myocardial infarction.

The effect of reperfusion achieved by early intracoronary streptokinase in acute myocardial infarction on left ventricular function was studied in 533 patients enrolled in a prospective randomised multicentre study. Two hundred and sixty four patients were allocated to conventional treatment and 269 patients to thrombolysis. At the end of the procedure patency of the infarct related vessel was achieved in 198 (85%) of 234 patients in whom coronary angiography was performed. The median interval from onset of symptoms till the angiographic documentation of patency was 200 minutes. Data were analysed according to the original treatment allocation. Global left ventricular ejection fraction was determined by radionuclide angiography in 418 patients within two days of admission, in 361 patients after two weeks, and in 307 patients after three months. Global left ventricular function remained unchanged throughout the observation period in the control group, whereas it improved during the first two weeks in patients allocated to thrombolytic treatment. Improved function in these patients persisted up to three months after the infarction. Global left ventricular ejection fraction was significantly better in the thrombolysis group than in the control group at two days, two weeks, and at three months. In patients with anterior myocardial infarction the left ventricular ejection fraction was 9% better than in the control group at two weeks and at three months. In the patients with inferior myocardial infarction differences between the two treatment groups were smaller because of photon attenuation within the body. Angiographic evidence suggested that the improvement in function seen after thrombolysis is indeed associated with the patency of the infarct related artery.

Aged↗

Assessment for prognosis during and after myocardial infarction. A plea for a stratified approach.

Right after the first signs and symptoms of acute myocardial infarctions the prognosis is determined by the interventions which are carried out at that time. Preservation of as much myocardial tissue is the key element. Early deobstruction and reperfusion of the myocardium at jeopardy can lead to limitation of the ultimate infarct size, improved ventricular function and a halving of the 1-year mortality. Early supportive therapy with beta-blockade and calcium antagonists may enhance this effect. Data in 533 patients randomized to either a reperfusion strategy or to conventional therapy, combined with those from the recent literature on thrombolysis and early beta-blockade, provide the basis for this point of view. Once infarction is unavoidable and in the process of completion, probably 3-4 h after onset of symptoms, only supportive therapy is recommended, which will hardly change the outcome except for interventions during clinical care such as defibrillation. In 351 other survivors of myocardial infarction the value of clinical variables, a symptom-limited bicycle stress test at discharge, radionuclide ventriculography and 24-hour ambulatory electrocardiogram was compared in predicting 1-year survival. A history of previous myocardial infarction and heart failure during the current episode proved to be the strongest clinical predictors of death. Similarly, a low ejection fraction (less than 40%) and an insufficient blood pressure rise during stress testing (less than 30 mm Hg) identified a high risk group. Stress-test-induced angina and ST depression as well as ventricular arrhythmias from 24-hour electrocardiography were less good as predictors. In these patients treatment should be individualized and may require arteriography. Patients eligible for and completing a normal bicycle stress test after myocardial infarction proved to be a low risk group, which may constitute 65% of the total, seen in tertiary referral centers and even more in community hospitals. They neither require therapy nor further investigation. A subgroup with an intermediate risk can be identified when clinical variables, stress testing and/or resting radionuclide ventriculography are abnormal. This group requires 'tailored' therapy. Therefore, after infarction recovery, we recommend a pre-discharge stress test routinely to complement the clinical evaluation, since it also provides information on physical capacity, the indication of arrhythmias and the presence of myocardial ischemia. Thus, optimal management of acute myocardial infarction requires a stratified approach, which does not require expensive testing procedures.

Female↗

Which patients benefit most from early thrombolytic therapy with intracoronary streptokinase?

The effect of thrombolysis in acute myocardial infarction on enzymatic infarct size, left ventricular function, and early mortality was studied in subsets of patients in a randomized trial. Early thrombolytic therapy with intracoronary streptokinase (152 patients) or with intracoronary streptokinase preceded by intravenous streptokinase (117 patients) was compared with conventional treatment (264 patients). All 533 patients were admitted to the coronary care unit within 4 hr after onset of symptoms indicative of acute myocardial infarction. Four hundred eighty-eight patients were eligible for this detailed analysis, and 245 of these were allocated to thrombolytic therapy and 243 to conventional treatment. Early angiographic examinations were performed in 212 patients allocated to thrombolytic therapy. Patency of the infarct-related artery was achieved in 181 patients (85%). Enzymatic infarct size, as measured from cumulative alpha-hydroxybutyrate dehydrogenase release, was smaller in patients allocated to thrombolytic therapy (median 760 vs 1170 U/liter in control patients, p = .0001). Left ventricular ejection fraction measured by radionuclide angiography before discharge from the hospital was higher after thrombolytic therapy (median 50% vs 43% in control patients, p = .0001). Three month mortality was lower in patients allocated to thrombolytic therapy (6% vs 14% in the control group, p = .006). With the use of multivariate regression analysis, infarct size limitation, improvement in left ventricular ejection fraction, and three month mortality were predicted by sum of the ST segment elevation, time from onset of symptoms to admission, and Killip class at admission. Thrombolysis was most effective in patients admitted within 2 hr after onset of symptoms and in patients with a sum of ST segment elevation of 1.2 mV or more. On the other hand, no beneficial effects of streptokinase on enzymatic infarct size, left ventricular function, or mortality were observed in the subset of patients with a sum of ST segment elevation of less than 1.2 mV who were admitted between 2 and 4 hr after onset of symptoms.

Cardiac Catheterization↗

Thrombolytic therapy for acute coronary obstruction: status in 1986.

The effect of thrombolysis in acute myocardial infarction on enzymatic infarct size, left ventricular function, and early mortality was studied in subsets of patients in a randomized trial at The Netherlands Interuniversity Cardiological Institute during a 5-year period. Early thrombolytic therapy with intracoronary streptokinase (152 patients) or with intracoronary streptokinase preceded by intravenous streptokinase (117 patients) was compared to conventional treatment (264 patients). All 533 patients were admitted to the coronary care unit within 4 hours after onset of symptoms indicative of acute myocardial infarction. There were 488 patients eligible for this detailed analysis, of whom 245 were allocated for thrombolytic therapy. Early angiography was performed in 212 of the 245 patients. Patency of the infarct-related artery was achieved in 181 patients (85%). Enzymatic infarct size measured from cumulative alpha HBDH release was smaller in patients allocated to thrombolytic therapy (median 760 U/l vs. 1179 U/l in controls, p = 0.0001). LVEF measured by radionuclide angiography before discharge was higher after thrombolytic therapy (median 50% vs. 43% in controls, p = 0.0001). The 12-month mortality was lower in patients allocated to thrombolytic therapy (8% vs. 16% in the control group, p < 0.01). In multivariate regression analysis, infarct size limitation, improvement of LVEF, and a 3-month mortality were predicted by ST, time from onset of symptoms to admission, and Killip class at admission. Thrombolysis was most useful in patients admitted within 2 hours after onset of symptoms and in patients with ST of 1.2 mV or more. On the other hand, no beneficial effects of streptokinase on enzymatic infarct size, left ventricular function, or mortality were observed in the subset of patients with ST less than 1.2 mV admitted 2 to 4 hours after onset of symptoms. In the long term, improved survival and enhanced quality of life are most evident after thrombolytic therapy in patients with larger anterior wall infarction, and less pronounced in patients with smaller inferior wall infarction.

Journal Article↗

Improved survival after early thrombolysis in acute myocardial infarction. A randomised trial by the Interuniversity Cardiology Institute in The Netherlands.

Two strategies for treatment of acute myocardial infarction were compared in a randomised trial of 533 patients admitted within 4 h of the onset of symptoms. 264 patients were allocated to conventional treatment and 269 patients to a strategy aimed at rapid recanalisation of the occluded coronary artery. At first, intracoronary streptokinase (up to 250 000 U) was given immediately after angiography. In the last 117 patients intracoronary administration was preceded by intravenous streptokinase (500 000 U). No angiography was done in 35 patients allocated to thrombolytic therapy. Among the 234 patients who underwent angiography the infarct-related coronary artery was patent on admission or recanalised in 198 (85%). The median time between onset of symptoms and angiographic confirmation of a patent infarct-related artery was 200 min. Mortality was lower in patients randomised to thrombolysis than in controls at 28 days (16 v 31 patients) and at 8 months (23 v 42); 1-year survival was higher after thrombolysis (91%) than conventional treatment (84%). The clinical course in hospital was more favourable in patients allocated to thrombolysis, with a lower incidence of ventricular fibrillation (38 v 61), pericarditis (19 v 46), and cardiogenic shock (13 v 24), although they had a higher frequency of bleeding episodes (53 v 7). Non-fatal reinfarction was commoner after thrombolysis than after conventional therapy (36 V 16 patients). In both groups reinfarctions occurred predominantly in the same area as the initial infarct.

Aged↗

Prediction of mortality during the first year after acute myocardial infarction from clinical variables and stress test at hospital discharge.

The predictive value of a predischarge symptom-limited stress test was studied in 405 consecutive survivors of acute myocardial infarction (AMI). Three hundred patients performed bicycle ergometry; 105 could not perform it. Among these latter 105 patients, the stress test was contraindicated in 43 because of angina or heart failure and in 62 because of noncardiac limitations. One-year survival was 44% in the "cardiac-limited" group (19 of 43) and 92% in the "non-cardiac-limited" group (57 of 62). One-year survival among the patients who performed an exercise test at discharge was 93% (280 out of 300). The best stress test predictor of mortality by univariate analysis was the extent of blood pressure (BP) increase: 42 +/- 24 mm Hg in 280 survivors vs 21 +/- 14 mm Hg in 20 nonsurvivors (p less than 0.001). Among the 212 patients in whom BP increased 30 mm Hg or more, mortality was 3% (n = 6), while it was 16% (n = 14) among the 88 patients in whom BP increased less than 30 mm Hg. Angina, ST changes and arrhythmias were not as predictive. Stepwise discriminant function analysis showed inadequate BP increase to be an independent predictor of mortality. A high-risk group can be identified at discharge on clinical grounds in patients unable to perform a stress test, whereas intermediate- and low-risk groups can be identified by the extent of BP increase during exercise.

Aged↗

Early detection of restenosis after successful percutaneous transluminal coronary angioplasty by exercise-redistribution thallium scintigraphy.

The value of exercise testing and thallium scintigraphy in predicting recurrence of angina pectoris and restenosis after a primary successful transluminal coronary angioplasty (PTCA) was prospectively evaluated. In 89 patients, a symptom-limited exercise electrocardiogram (ECG) and thallium scintigraphy were performed 4 weeks after they had undergone successful PTCA. Thereafter, the patients were followed for 6.4 +/- 2.5 months (mean +/- standard deviation) or until recurrence of angina. They all underwent a repeat coronary angiography at 6 months or earlier if symptoms recurred. PTCA was considered successful if the patients had no symptoms and if the stenosis was reduced to less than 50% of the luminal diameter. Restenosis was defined as an increase of the stenosis to more than 50% luminal diameter. The ability of the thallium scintigram (presence of a reversible defect) to predict recurrence of angina was 66%, vs 38% for the exercise ECG (ST-segment depression or angina at peak workload). Restenosis was predicted in 74% of patients by thallium scintigraphy, but only in 50% of patients by the exercise ECG. Thus, thallium scintigraphy was highly predictive but the exercise ECG was not (p less than 0.005). These results suggest that restenosis had occurred to some extent already at 4 weeks after the PTCA in most patients in whom it was going to occur.

Angina Pectoris↗

Left ventricular performance in unstable angina: assessment with radionuclide techniques.

In a clinical trial we studied left ventricular performance at rest in 50 patients with unstable angina by radionuclide techniques. Thallium-201 scintigraphy was performed on admission in 38 patients and repeated after 48 hr in 32 patients. Also dynamic blood pool scintigraphy was performed in 37 patients on admission and in 45 patients after 48 hr. Of the 50 patients, 27 (54%) had no recurrent episodes of myocardial ischemia, but 23 (46%) patients showed recurrent ischemic episodes of whom 11 (22%) patients developed a myocardial infarction. The thallium-201 images showed perfusion defects in 27 (71%) of the 38 patients studied on admission and in 20 (63%) of the 32 patients studied at 48 hr. No relation between clinical outcome and presence or absence of defects was observed. Left ventricular ejection fraction was abnormal (less than 50%) in 19 (51%) of the 37 patients on admission and in 29 (64%) of the 45 patients studied at 48 hr. As with thallium-201, no relation could be established between clinical outcome and left ventricular ejection fraction. It is concluded that radionuclide techniques are useful to provide insight into the pathophysiological mechanism of unstable angina, but they are not helpful for the short-time assessment of clinical outcome.

Angina Pectoris↗

Prognosis of patients with different peak serum creatine kinase levels after first myocardial infarction.

The extent to which patients with low peak serum creatine kinase (CK) at their first myocardial infarction differ from patients with high CK levels in terms of risk for subsequent ischaemic events was investigated in 266 patients who survived the first 48 h from the onset of infarction. All patients were followed up for one year. Four groups were formed based on peak CK less than or equal to 200, 201-400, 401-800 and greater than 800 IU l-1. During follow-up the incidence of mortality was 15% (N = 39), non-fatal re-infarction 9% (N = 23), and angina 53% (N = 140). Hospital mortality was significantly higher (P less than 0.02) in the highest CK-group (16%), but the incidence of non-fatal re-infarction, angina pectoris and late mortality was similar in the four groups. In hospital survivors, ischaemic ST-changes during pre-discharge symptom limited bicycle stress test and multiple vessel disease were equally distributed in all four groups. We conclude that while hospital mortality is directly related to peak CK, there is no relationship between peak CK and late mortality, non-fatal re-infarctions, or recurrent angina. Accordingly, diagnostic and therapeutic procedures in the individual patients are not influenced by the amount of serum CK released during acute infarction.

Creatine Kinase↗

Recording the right atrial electrogram through the fluid column of a pulmonary artery catheter.

Analysis of the cardiac rhythm in patients with ventricular and supraventricular tachycardia can be difficult because P-waves tend to be obscured by other components of the ECG. Recording of the intracavitary electrogram by means of pacing wires and the use of esophageal leads can be very helpful under these circumstances. Because a number of these patients are monitored with pulmonary artery catheters, we developed a method to obtain the atrial electrogram using the fluid column of the pulmonary artery catheter as an electrical conductor. Only slight modifications of the ECG equipment were necessary.

Arrhythmias, Cardiac↗

Intracoronary streptokinase in acute myocardial infarction. A review.

The attempt to salvage myocardium threatened by ischemia during temporary or permanent occlusion of one or more of the nutrient arteries, is based on the observation that the major determinant of survival is the extent to which myocardium has been lost through infarction. Modern clinical cardiology has therefore looked at various approaches which might limit unnecessary loss of potentially viable myocardium. These are attempts to reduce the oxygen consumption through pharmacological means, attempts at restoring the blood supply and oxygen delivery at an early stage by manipulations on the coronary arteries and interventions aimed at "protecting" cardiac cells threatened by ischemia or reperfusion. Endpoints considered to be proof of improved left ventricular function will be wall motion and ejection fraction measurements as well as reduction in death rate and other serious cardiovascular complications. Although final proof from prospective randomized studies, one of which is carried out at this institution with intracoronary streptokinase in over 300 patients, will not be available at the time of this presentation, arguments will be provided which indicate that restoration of blood supply at an early stage, preferably supported by pharmacological therapy with beta-blockade and calcium antagonists, is to be preferred inasmuch as current data indicate improved function, and in certain subsets, improved life expectancy.

Angioplasty, Balloon↗

Predictive value of early maximal exercise test and thallium scintigraphy after successful percutaneous transluminal coronary angioplasty.

Restenosis of the dilated vessel after percutaneous transluminal coronary angioplasty can be detected by non-invasive procedures but their ability to predict later restenosis soon after a successful angioplasty as well as recurrence of angina has not been assessed. A maximal exercise test and myocardial thallium perfusion scintigraphy were, therefore, performed in 91 asymptomatic patients a median of 5 weeks after they had undergone a technically successful angioplasty. Primary success of the procedure was confirmed by the decrease in percentage diameter stenosis from 64(12)% to 30(13)% as measured from the coronary angiograms and in the trans-stenotic pressure gradient (normalised for mean aortic pressure) from 0.61(0.16) to 0.17(0.09). A clinical follow up examination (8.6(4.9) months later) was carried out in all patients and a late coronary angiogram obtained in 77. The thallium perfusion scintigram showing the presence or absence of a reversible defect was highly predictive for restenosis whereas the exercise test was not. The positive predictive value of an abnormal scintigram was 82% compared with 60% for the exercise test (ST segment depression/or angina or both at peak workload). Angina or a new myocardial infarction occurred in 60% of patients with abnormal and in 21% of patients with normal scintigrams.

Adult↗