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Coronary thrombolysis with recombinant tissue-type plasminogen activator: patency rate and regional wall motion after
Insights
Recombinant tissue-type plasminogen activator (rt-PA) improved coronary artery patency after myocardial infarction. While rt-PA did not significantly enhance left ventricular function compared to placebo, it demonstrated no antigenicity, allowing for potential repeat administration.
Area of Science:
- Cardiology
- Pharmacology
- Biochemistry
Background:
- Myocardial infarction (MI) remains a leading cause of cardiovascular mortality.
- Restoring coronary blood flow is crucial for preserving left ventricular function post-MI.
- The efficacy and safety of thrombolytic agents like recombinant tissue-type plasminogen activator (rt-PA) require long-term evaluation.
Purpose of the Study:
- To compare the long-term effects of intravenous rt-PA versus placebo on left ventricular function and coronary artery patency in patients with first myocardial infarction.
- To assess the antigenicity of rt-PA in this patient population.
- To evaluate the relationship between coronary patency and left ventricular function recovery.
Main Methods:
- A double-blind, placebo-controlled, randomized trial involving 28 patients with a first myocardial infarction.
- Intravenous administration of rt-PA or placebo.
- Assessment of coronary patency rates at the end of infusion and after 3 months of medical treatment.
- Quantification of regional wall motion using digital subtraction angiography.
- Serological testing for antibodies against rt-PA.
Main Results:
- Coronary artery patency rates were significantly higher in the rt-PA group (71% at 3 months) compared to the placebo group (58% at 3 months).
- Both rt-PA and placebo groups showed significant improvement in regional wall motion, with no significant difference between groups.
- Patients with persistent coronary artery patency (early and late) demonstrated improved global and regional left ventricular function, irrespective of treatment group.
- No antibodies against rt-PA were detected, indicating a lack of antigenicity.
Conclusions:
- Intravenous rt-PA significantly improves long-term coronary artery patency after myocardial infarction compared to placebo.
- While rt-PA does not independently enhance left ventricular function recovery beyond placebo, maintaining coronary patency is critical for functional improvement.
- rt-PA exhibits a favorable safety profile with no detected antigenicity, supporting its potential for repeated administration.
Abstract:
In a double-blind, placebo-controlled, randomized trial the long-term (+/- 3 months) effects of intravenous administration of recombinant tissue-type plasminogen activator (rt-PA) versus placebo were compared in relation to left ventricular function, coronary patency rate and antigenicity in 28 patients with a first myocardial infarction. Patency rate of the infarct-related coronary artery at the end of the rt-PA/placebo infusion and after 3 months of medical treatment (including oral anticoagulant agents) was 86 and 71%, respectively, in the rt-PA group, and 21 and 58%, respectively, in the placebo group. Regional wall motion of the infarct-related area was quantitated with digital subtraction angiography. Intrapatient comparisons revealed significant improvement in regional wall motion after 3 months in both the rt-PA and placebo groups. The improvement in the rt-PA group was not significantly greater than that in the placebo group. Thirteen patients (10 with rt-PA and 3 with placebo) with persistent patency (both early and late) of the infarct-related coronary artery showed a significant improvement of both global and regional left ventricular function, while 8 patients (2 with rt-PA and 6 with placebo) with persistent occlusion showed no changes. Antibodies against rt-PA were not detected in serum 2 weeks after the infusion, which is indicative of the lack of antigenicity of rt-PA and allows for its repeated administration.