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[Long-term therapy following myocardial infarct with isosorbide dinitrate in a low and high dose]
G Kober1, R Bettinger, H Klepzig
1Zentrum der Inneren Medizin, J.-W.-Goethe-Universität Frankfurt am Main.
Insights
Long-term isosorbide dinitrate (ISDN) therapy did not significantly impact patient prognosis after myocardial infarction. Different ISDN dosages showed no difference in major cardiac events over two years.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Trials
Background:
- Nitrates, including isosorbide dinitrate (ISDN), are known to benefit coronary heart disease by reducing cardiac load and improving coronary flow.
- Understanding the long-term effects of ISDN therapy on post-myocardial infarction prognosis is crucial for patient management.
Purpose of the Study:
- To investigate the long-term efficacy of different isosorbide dinitrate (ISDN) dosages in patients following myocardial infarction.
- To evaluate the impact of ISDN therapy on endpoints such as sudden cardiac death, reinfarction, and the need for revascularization.
Main Methods:
- A double-blind study involving 608 patients post-myocardial infarction.
- Patients were randomized into two groups receiving different daily dosages of ISDN (2.5 mg vs. 40 mg) for two years.
- Outcomes including cardiac death, reinfarction, revascularization, and adverse events were monitored.
Main Results:
- No significant differences were observed between the low-dose and high-dose ISDN groups regarding sudden cardiac death, reinfarction, or revascularization.
- The low-dose ISDN group required more frequent additional administration of calcium antagonists (p < 0.05).
- Drop-out rates due to lack of efficacy were higher in the low-dose group, while drop-outs due to side effects were more frequent (though not statistically significant) in this group as well.
Conclusions:
- Long-term ISDN therapy at the studied dosages did not demonstrate a significant benefit in improving prognosis for patients after myocardial infarction.
- Potential reasons for the lack of observed differences include ISDN dose-potency issues, low-dose ineffectiveness, absence of influence on target parameters, or insufficient follow-up duration.
- Further research is warranted to clarify the role and optimal dosing of ISDN in post-myocardial infarction care.
Abstract:
The favorable response to nitrates in the case of coronary heart diseases is based on both reduction in left ventricular pre- and afterload and improvement in coronary flow. These effects were studied in the setting of a long-term ISDN therapy with reference to the prognosis of patients after myocardial infarction. Following acute treatment in the respective hospitals, 608 patients with myocardial infarctions were allocated to two double-blind treatment groups with different ISDN dosage levels (group 1 = 5 x 2.5 mg i.d.; group 2 = 5 x 40 mg i.d.) and followed up over a period of 2 years. No differences were found with regard to the end points sudden cardiac death, reinfraction, and indication for revascularization. There was, however, a more frequent additional administration of calciumantagonists to patients of the low-dose group (p less than 0.05), a more frequent drop-out due to the lack of beneficial therapeutic results, and a more exceptional drop-out due to side effects in patients treated with low doses of ISDN (n.s.). The absence of any significant difference with regard to the end points might be attributed to; 1) a loss of potency of high-dose ISDN and simultaneous ineffectiveness of low-dose ISDN; 2) an efficacy of low doses; 3) an absence of actual influence on the target parameters, and 4) an inadequate follow-up time period.