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Intravenous streptokinase for acute myocardial infarction. Effects on global and regional systolic function
G V Martin1, F H Sheehan, M Stadius
1Department of Medicine, University of Washington School of Medicine, Seattle.
Insights
Intravenous streptokinase significantly improved artery patency and preserved left ventricular function in acute myocardial infarction patients. This thrombolytic therapy also enhanced the function of non-infarct regions, offering broader cardiac benefits.
Area of Science:
- Cardiology
- Thrombolytic Therapy
- Myocardial Infarction
Background:
- Acute myocardial infarction (AMI) poses significant risks to left ventricular (LV) function.
- Thrombolytic therapy aims to restore blood flow and improve outcomes in AMI.
- Evaluating the impact of thrombolytic agents on global and regional cardiac function is crucial.
Purpose of the Study:
- To assess the effects of intravenous streptokinase on global and regional systolic function in patients with acute myocardial infarction.
- To compare the efficacy of streptokinase versus standard therapy in improving infarct-related artery patency and LV function.
Main Methods:
- Randomized trial involving 368 AMI patients, comparing intravenous streptokinase to standard therapy.
- Ventriculography and coronary angiography performed on 170 patients post-infarction.
- Analysis of global systolic function (ejection fraction) and regional wall motion using the centerline method.
Main Results:
- Streptokinase significantly increased infarct-related artery patency (68.5% vs. 44.8%, p=0.003).
- Higher ejection fraction observed in streptokinase group (54% vs. 51%, p=0.056), particularly in anterior MI (53% vs. 44%, p=0.03).
- Improved regional wall motion in non-infarct areas (SD, 0.36 vs. -0.08, p=0.02) with streptokinase, especially in multivessel disease.
Conclusions:
- Intravenous streptokinase effectively preserves left ventricular function in acute myocardial infarction.
- Thrombolytic therapy with streptokinase demonstrates benefits beyond the infarct zone, improving function in remote myocardial regions.
- Streptokinase is a valuable therapeutic option for managing acute myocardial infarction and its impact on cardiac function.
Abstract:
The Western Washington Intravenous Streptokinase Trial randomized 368 patients with acute myocardial infarction to receive either intravenous streptokinase or standard therapy. The ventriculograms and coronary angiograms obtained in 170 patients 10.4 +/- 7.4 days after infarction were analyzed to evaluate the effects of thrombolytic therapy on global and regional systolic function. Streptokinase treatment resulted in a higher patency rate of the infarct-related artery (68.5%) than did standard therapy (44.8%) (p = 0.003). Ejection fraction was higher in streptokinase-treated patients (54% vs. 51%, p = 0.056), and the difference was most marked in patients with anterior myocardial infarction (53% vs. 44%, p = 0.03). Regional wall motion was measured by the centerline method and expressed in mean +/- SD motion in 52 normal subjects. There was a trend toward better function of the infarct zone in streptokinase-treated patients (SD, -2.48 vs. -2.70, p = 0.24). Additionally, streptokinase-treated patients had significantly better wall motion of noninfarct areas (SD, 0.36 vs. -0.08, p = 0.02). Treatment effects on function of noninfarct regions were most apparent in the subset of patients with multivessel disease. Thus, intravenous streptokinase preserves left ventricular function in patients with acute myocardial infarction. This benefit includes favorable effects on the function of regions remote from the site of infarction.