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M L Simoons

Publications and source records attributed to M L Simoons.

At least 199 records · Page 11Linked to original sources
PubMed1991

Strategies for pre-hospital thrombolysis: an overview.

Improvement in survival as a result of thrombolytic therapy in patients with myocardial infarction is determined by the delay between coronary occlusion and reperfusion. Treatment at home can reduce this delay, provided that appropriate patients can be identified. Different strategies for pre-hospital thrombolysis have been developed. Most studies require ECG confirmation of evolving myocardial infarction. In many, the ECG is interpreted by a physician in the ambulance. Others transmit the ECG to a remote physician or use computer analysis of an ECG made 'on the spot', A few studies use no ECG criteria at all. The pooled data show that with physician interpretation, 723 patients in 14 studies could be treated within 103 min after onset of symptoms (range 60-138 min) with a time gain of 51 min (range 30-74 min), compared with thrombolytic treatment after hospital admission. The therapeutic delay was 93 +/- 45 min (SD) with time gains of 62 and 86 min in two studies with ECG transmission (61 patients). In another study using computer analysis, ambulance nurses were able to treat 300 patients within 102 +/- 63 min after onset of symptoms, resulting in a time gain of 48 +/- 2 min. Without ECG confirmation, cardiologists accompanying the ambulance could administer thrombolysis within 83 +/- 4 min after onset of symptoms with a time gain of 45 min in one study. The diagnostic accuracy of this last approach was 42%. With each of the four approaches, patients can be treated within approximately 100 min after onset of symptoms, resulting in a time gain of 45 min or more.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory Care↗
PubMed1990

[Earlier treatment of acute myocardial infarction with administration of alteplase (rt-PA) before hospitalization].

The gain in survival by thrombolytic therapy in patients with myocardial infarction is determined by the delay between coronary occlusion and reperfusion. The REPAIR study was designed to examine the feasibility and safety of prehospital thrombolysis with alteplase (rt-PA, Actilyse). Indications and contraindications are verified by general practitioner or ambulance nurse with a short questionnaire. A small portable ECG computer system is used to confirm the presence of a large evolving myocardial infarction 'on the spot'. Between June 1988 and May 1990, 150 patients were treated by the ambulance service. Therapy could be initiated within an average of 91 (+/- 40) minutes (sd) after the onset of symptoms, and within 23 (+/- 9) minutes after ambulance arrival. Three patients were defibrillated during transportation, in one of these therapy had to be discontinued because of cardiac massage. No other complications were observed. Five patients (3%) died after arrival in the hospital. The time gained by prehospital treatment averaged 47 (+/- 2) minutes in comparison with 220 patients who received thrombolytic therapy after hospital admission. The procedure allows rapid and safe initiation of thrombolytic therapy in selected patients, even in the absence of a physician.

Acute Disease↗
PubMed1990

[Early thrombolysis improves the long-term prognosis for patients with a heart infarct].

In a previously reported clinical study treatment of myocardial infarction with intracoronary streptokinase (269 patients) was compared with conventional therapy (264 patients). To determine the long-term effects of thrombolytic therapy patient data were collected from 3 to 7 years after admission. Three-year survival rates were 87% after thrombolysis and 79% after conventional therapy. Bypass surgery was done in 19% versus 16%, and PTCA in 9% versus 6% of patients. Patients treated with thrombolysis also had a better prognosis after discharge. The difference in survival between the two treatment groups was 6% after 1 year and 10% after 5 years. Benefit was largest in patients with an anterior infarction, patients with extensive myocardial ischaemia and patients treated shortly after onset of infarction. Left ventricular function appeared to be the best determinant predicting survival after discharge. The findings show that early thrombolysis after acute myocardial infarction also results in improved long-term survival.

Aged↗
PubMed1990

[An unexpected complication of exercise testing].

A male patient 40 years of age died after diagnostic exercise testing for stable exercise induced angina, which had existed for two months. The ECG prior to the stress was normal and there had been no signs of unstable angina. The exercise test was discontinued at a load of 120 Watts because of angina without significant ECG changes. Subsequently shock developed with widening of the QRS complex. Immediate coronary angiography revealed an occluded main stem of the left coronary artery. Although recanalisation was achieved, the patient died. The risks of exercise testing and the appropriate precautions are discussed. Laboratories for stress testing of patients with suspected coronary diseases should be located in a hospital with facilities for coronary care.

Adult↗
PubMed1990

Changes in the electrocardiographic response to exercise in healthy women.

Changes in the P wave, QRS complex, ST segment, and T wave during and after maximal exercise were quantitatively analysed in 116 healthy women with a mean age of 39. The corrected orthogonal Frank lead electrocardiogram was continuously recorded and computer processed during bicycle ergometry. With exercise, maximal spatial P wave vectors shifted downward. The Q wave amplitude became more negative and the R wave amplitude diminished considerably in leads X and Y: the S wave amplitude decreased only slightly in these leads. The QRS vectors shifted towards right and posteriorly during exertion and a further shift in the same direction was seen in the recovery period. The ST segment amplitude 60 ms after the J point decreased with exertion and became negative at heart rates above 140 beats per minute, in particular in lead Y. ST segment depression increased with age. The T wave amplitude decreased during exercise and increased sharply in the recovery period. Though mean R wave amplitude in leads X and Y became more negative with exercise, this response was unpredictable in individual women. The exercise induced changes in QRS vectors in women resembled those described in men. Changes in the amplitude of the R wave should not be used for the diagnosis of coronary disease in women. ST segment depression was more pronounced in the inferiorly oriented lead Y than in lead X but it was unrelated to changes in the QRS vectors in these leads.

Adult↗
PubMed1989

Long-term benefit of early thrombolytic therapy in patients with acute myocardial infarction: 5 year follow-up of a trial conducted by the Interuniversity Cardiology Institute of The Netherlands.

Patients (n = 533) who participated in the Interuniversity Cardiology Institute of the Netherlands Trial were followed up for 3 to 7 years. The 5 year survival rate after thrombolytic therapy with intracoronary streptokinase was 81% (269 patients) compared with 71% after conventional therapy (264 patients). The greatest improvement in survival was observed in patients with anterior infarction (81% versus 64% with thrombolytic therapy or conventional therapy, respectively), in those with heart failure on admission or a previous infarction and in those with extensive myocardial ischemia on admission. Left ventricular ejection fraction at the time of hospital discharge was better after thrombolytic therapy. In the hospital survivors, long-term outcome was related to left ventricular function at the time of discharge and, to a lesser extent, to the underlying coronary artery disease. The initial therapy (thrombolysis or conventional) was not an independent additional determinant of long-term survival when left ventricular function and coronary status at the time of hospital discharge were taken into account. Thus, the salutary effects of thrombolytic therapy appear to be the result of myocardial salvage. Reinfarction within 3 years was observed more frequently after thrombolytic therapy, particularly in patients with inferior wall infarction and those with greater than or equal to 90% stenosis of the infarct-related vessel at discharge. Coronary bypass surgery and coronary angioplasty were performed more frequently after thrombolytic therapy than in conventionally treated patients. At 5 years, approximately 40% of patients in both groups had an uneventful course without reinfarction or additional revascularization procedures. These observations demonstrate that the benefits of thrombolytic therapy are maintained throughout 5 years of follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
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

Diagnostic merits of exercise testing in females.

The diagnostic accuracy of conventional exercise electrocardiography was compared with exercise algorithms specifically aimed at application in females, with R wave and heart rate adjusted ST-segment changes, and with discriminant analysis. A symptom-limited bicycle exercise test was performed by 189 females without previous infarction with a normal electrocardiogram (ECG) at rest. Frank lead ECG was computer processed. ST-segment amplitudes in lead X were superior to measurements in lead Y, but their sensitivity amounted only to 50% at a specificity of 90%. Correction for R wave amplitude marginally increased sensitivity. It was confirmed that leads with inferiorly directed vectors such as standard leads II, III, aVF or Frank lead Y should not be used for diagnostic purposes in females. Exercise-induced increases in R-wave amplitude of at least 0.1 mV occurred in only 8% of females with coronary disease. Previously described discriminant function using attained heart rate, ST-segment depression and a sex-dependent ST segment correction factor yielded a sensitivity of 60% at a specificity of 90%. Sensitivities of heart rate adjusted ST-segment changes and of a previously proposed discriminant function were greater than 70% at a specificity of 90%. It is concluded that the diagnostic yield of exercise testing in females can be improved by use of more sophisticated electrocardiographic and exercise variables.

Coronary Disease↗
PubMed1989

Indirect enzyme-linked immunosorbent assay for immunoglobulin G and four immunoassays for immunoglobulin M to Toxoplasma gondii in a series of heart transplant recipients.

Toxoplasma gondii infections in heart transplant recipients were monitored by indirect enzyme-linked immunosorbent assay for immunoglobulin G (ELISA-IgG), indirect ELISA-IgM in serum IgM fractions, antibody capture ELISA-IgM, IgM-immunosorbent agglutination assay (ISAGA), and IgM immunoblotting. Basic immunosuppression consisted of cyclosporine and low-dose steroids. Before transplantation, 26 of 43 recipients showed serological evidence of infection. In serum samples from 15 (35%) recipients, specific antibodies were not detected. Approximately 50% of the heart donors, were toxoplasma seropositive. Eight of the fifteen seronegative recipients received hearts from toxoplasma-seropositive donors. In four of the eight recipients, seroconversion could be demonstrated with all tests used. In three of these four patients, clinical disease developed. One patient with strong serological evidence of toxoplasmosis died, but toxoplasma parasites and antigens were not detected at autopsy. In two patients, toxoplasma cysts were found in cardiac biopsies. Seroconversion was not prevented by the use of spiramycin prophylaxis in two recipients. Reactivations of latent infections or reinfections were detected by indirect ELISA in six (23%) seropositive recipients, but symptoms and signs of active T. gondii infection were not seen. Seroconversion and reactivation of infection were readily found by a combined use of indirect ELISA-IgG and ELISA-IgM and antibody capture ELISA-IgM. Discrepancies in results could be examined by immunoblotting. IgM-ISAGA retained stable positive values longer than IgM-ELISAs did. Cyclosporine treatment did not hamper detection of seroconversion but could cause antibody levels to remain relatively low in primary infections. Seronegative recipients should receive antitoxoplasma treatment on seroconversion.

Agglutination Tests↗
PubMed1989

A comparison of methods of analysing exercise tests for diagnosis of coronary artery disease.

The diagnostic accuracy of the following methods of analysing exercise tests were evaluated: (a) the cumulative area of ST segment depression during exercise normalised for workload and heart rate (exercise score); (b) discriminant analysis of electrocardiographic exercise variables, workload, and symptoms; and (c) ST segment amplitude changes during exercise adjusted for heart rate. Three hundred and forty five men without a history of myocardial infarction were studied. One hundred and twenty three were apparently healthy. Less than half (170) had coronary artery disease. All had a normal electrocardiogram at rest. A Frank lead electrocardiogram was computer processed during symptom limited bicycle ergometry. The accuracy of the exercise score (a) was low (sensitivity 67%, specificity 90%). Discriminant analysis (b) and ST segment amplitude changes adjusted for heart rate (c) had excellent diagnostic characteristics (sensitivity 80%, specificity 90%), which were little affected by concomitant use of beta blockers. Both methods seem well suited for diagnostic application in clinical practice.

Adult↗
PubMed1989

Thrombolytic therapy in acute myocardial infarction.

Early thrombolytic therapy has been shown to reduce hospital mortality after myocardial infarction by 20-50%. This is achieved through reperfusion of the ischemic myocardium, which leads to limitation of infarct size by 15-30% and preservation of regional and global left ventricular function. Thrombolysis and reperfusion can be achieved by intravenous administration of streptokinase, urokinase, APSAC, or rt-PA, or by intracoronary administration of streptokinase or urokinase. Thrombolytic therapy is most effective in patients with extensive myocardial ischemia (large infarction) treated early after the onset of symptoms, but also patients with smaller infarcts may benefit from the therapy. It is uncertain whether treatment later than six hours after the onset of symptoms is beneficial, and if so, in which patients. Thrombolytic therapy leads to bleeding complications in a minority of patients. The risk of intracranial bleeding is approximately 0.5%. However, in several large trials the rate of cerebrovascular accidents (bleeding plus embolism) was not higher after thrombolytic therapy with streptokinase or rt-PA than after placebo. In order to prevent rethrombosis, additional treatment with acetyl salicylic acid and heparin is recommended. Nitrates and antiarrhythmic drugs are not recommended as routine practice. Immediate PTCA does not improve patient outcome. At present angiography and subsequent angioplasty or bypass surgery is recommended in patients with recurrent ischemia (spontaneous or upon exercise) after the infarct.

Angioplasty, Balloon↗
PubMed1989

Acute consequences of ischemic myocardial damage.

The current revolution in the treatment of acute myocardial infarction by means of thrombolytic therapy has as its underlying strategy three aims: early restoration of the blood flow in order to salvage jeopardized but still viable tissues; limitation of acute consequences of ischemic heart disease, such as infarct size, ventricular fibrillation, and pericardial effusion; and preservation, as far as possible, of ventricular function. It is also hoped that these three achievements will result in reduced short- as well as long-term mortality rates. The techniques employed in this overall strategy are still under investigation, and several leading pharmacological compounds vie for supremacy: streptokinase (SK) and its anisoylated form (APSAC), recombinant technique tissue type plasminogen activator (rt-PA), and urokinase (UK) with or without prourokinase (PUK). Other pharmacological agents, such as angiotensin converting enzyme (ACE) inhibitors, beta-blockers, Ca2+ antagonists, and O2 radical scavengers, might find here their "finest hour" yet. In addition, the underlying anatomy may require early or, where needed, delayed PTCA, backed up by coronary artery bypass grafting. Thus, the tactics of the intervention may vary from case to case and indeed from center to center depending on experience and facilities, but the strategic conclusion is clearly the same: early reperfusion is a must if one wishes to save ischemic but still viable tissue.

Acute Disease↗
PubMed1989

Reocclusion/restenosis after coronary artery bypass surgery, percutaneous transluminal coronary angioplasty and thrombolysis.

Occlusion, reocclusion, and/or restenosis after interventions can be due to four mechanisms which require different approaches: 1) mechanical problems should be prevented by careful surgery and PTCA; 2) early platelet aggregation and thrombosis can be reduced by acetylsalicylic acid; 3) fibrocellular hyperplasia leading to restenosis after PTCA. So far prevention has been unsuccessful; and 4) progression of coronary disease, which may be prevented or delayed by rigorous reduction of risk factors and lipid lowering drugs, while again, acetylsalicylic acid may prevent late platelet aggregation and infarction.

Angioplasty, Balloon↗