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Left ventricular function after anisoylated plasminogen streptokinase activator complex
M Been1, A L Muir, D P de Bono
1Department of Cardiology, Freeman Hospital, Newcastle upon Tyne.
Insights
Early administration of anisoylated plasminogen streptokinase activator complex (APSAC) preserves left ventricular function after myocardial infarction. Prompt treatment maximizes therapeutic benefits, highlighting the importance of timely thrombolytic therapy.
Area of Science:
- Cardiology
- Thrombolytic Therapy
- Myocardial Infarction Research
Background:
- Left ventricular function reduction post-myocardial infarction (MI) is a key outcome measure.
- Thrombolytic therapy aims to limit infarct size and preserve cardiac function.
- Anisoylated plasminogen streptokinase activator complex (APSAC) is a thrombolytic agent used in acute MI.
Purpose of the Study:
- To evaluate the efficacy of APSAC in preserving left ventricular function after acute myocardial infarction.
- To assess the impact of treatment timing and infarct location on therapeutic outcomes.
- To determine the early and late effects of APSAC on global left ventricular ejection fraction.
Main Methods:
- Radionuclide ventriculography used in 91 patients across 3 studies.
- APSAC administered within 4 hours of acute myocardial infarction onset.
- Left ventricular ejection fraction (LVEF) measured at 10 days and 6 months post-treatment.
Main Results:
- Successful APSAC therapy preserved LVEF in anterior infarctions at 10 days.
- Therapeutic benefit diminished with longer symptom duration before treatment.
- Benefit was less pronounced in inferior infarctions, with no significant LVEF improvement by 6 months in some groups.
- Early treatment led to greater LVEF preservation and potentially faster functional recovery.
Conclusions:
- Early administration of APSAC is crucial for preserving left ventricular function following acute myocardial infarction.
- Timing of thrombolytic therapy significantly influences patient outcomes.
- Infarct location affects the degree of benefit observed with APSAC treatment.
Abstract:
Limitation of the reduction in left ventricular function after acute myocardial infarction is an important indicator of benefit following thrombolytic therapy. Therefore, left ventricular function was studied by radionuclide ventriculography in 91 patients entering 3 separate studies of anisoylated plasminogen streptokinase activator complex (APSAC) administered within 4 hours of acute myocardial infarction. Global left ventricular ejection fraction was measured at 10 days and at 6 months to assess early and late effects of therapy, with particular emphasis on the timing of treatment and the site of infarction. Successful therapy with APSAC in anterior infarction resulted in preservation of left ventricular function at 10 days. The magnitude of benefit declined with increasing symptom duration before treatment, and was maintained at 6 months in those patients without reocclusion. The benefit of successful therapy was less marked in the inferior infarct group at 10 days. By 6 months, no significant benefit was detected because of an increase in ejection fraction in the placebo and occlusion or reocclusion group with inferior infarction. Early therapy results in greater preservation of left ventricular function, and recovery of function may be more rapid than with later treatment. More emphasis on early administration of thrombolytic therapy is indicated.