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A difference between front-loaded streptokinase and standard-dose recombinant tissue-type plasminogen activator in
G J Taylor1, H W Moses, D Koester
1Prairie Cardiovascular Center, Springfield, Illinois.
Insights
Recombinant tissue-type plasminogen activator (rt-PA) improved left ventricular function in anterior acute myocardial infarction (AMI) patients better than streptokinase. No significant differences were observed in inferior wall AMI cases.
Area of Science:
- Cardiology
- Pharmacology
- Medical Research
Background:
- Acute myocardial infarction (AMI) poses significant risks to left ventricular (LV) function.
- Thrombolytic therapy is crucial for restoring blood flow and preserving cardiac function post-AMI.
- Comparing different thrombolytic agents is essential for optimizing patient outcomes.
Purpose of the Study:
- To compare the efficacy of front-loaded streptokinase versus recombinant tissue-type plasminogen activator (rt-PA) in preserving LV function after AMI.
- To evaluate the impact of these therapies on global and regional LV ejection fraction.
Main Methods:
- A blinded, randomized trial involving 253 patients with first AMI treated within 4 hours of symptom onset.
- Patients received either streptokinase or rt-PA, along with aspirin and heparin.
- Left ventricular function was assessed using angiography within 24 hours and radionuclide angiography during convalescence.
Main Results:
- In anterior wall AMI patients, rt-PA significantly improved global LV ejection fraction compared to streptokinase (45% vs. 39%, p < 0.03).
- rt-PA demonstrated a persistent beneficial effect on LV regional wall contractility, but not global ejection fraction, in convalescent studies.
- No significant differences in LV function preservation were found between rt-PA and streptokinase for inferior wall AMI.
Conclusions:
- Front-loaded rt-PA offers superior benefits in preserving left ventricular function for patients with anterior acute myocardial infarction compared to streptokinase.
- The choice of thrombolytic agent may influence LV function recovery differently based on the infarct location.
- Further research may explore optimal thrombolytic strategies for specific AMI presentations.
Abstract:
A blinded, randomized trial compared the effects of front-loaded streptokinase with those of the conventional dose of intravenous recombinant tissue-type plasminogen activator (rt-PA) on left ventricular (LV) function after acute myocardial infarction (AMI). Thrombolytic therapy was administered in the emergency departments of 30 community hospitals in central Illinois, and subsequent studies were performed at 1 tertiary referral center. Patients aged < or = 75 years with a first AMI who could be treated within 4 hours of the onset of chest pain were randomly assigned to receive either streptokinase (375,000 IU bolus, followed by 1,125,000 IU over 1 hour) or rt-PA (10 mg bolus, followed by 50 mg in the first hour, and 20 mg/hour for the next 2 hours). All patients were treated with aspirin (325 mg) and intravenous heparin. Patients were transferred for angiography within 24 hours. During the 30-month study, 253 patients were treated with intravenous thrombolytic therapy 2.4 +/- 1.0 hour after the onset of AMI. In patients with anterior wall AMI (n = 90), global LV ejection fraction measured by angiography within 24 hours was 45 +/- 12% with rt-PA, and 39 +/- 13% with streptokinase (p < 0.03). Convalescent radionuclide angiography documented a persistent beneficial effect of rt-PA on LV regional wall contractility, but not global ejection fraction. There were no differences between rt-PA and streptokinase in preserving global or regional LV function in patients with inferior wall AMI.