Related Experiment Videos
What have the ACE-inhibitor trials in postmyocardial patients with left ventricular dysfunction taught us?
G Reynolds1, A S Hall, S G Ball
1Institute for Cardiovascular Research, Leeds University, UK.
Abstract:
A series of elegant experimental studies and careful clinical observation over a decade or more have led to the concept of 'infarct expansion' and 'remodelling' of the heart, culminating in a number of major mortality studies indicating the effectiveness of angiotensin-converting enzyme (ACE) inhibitors in patients after myocardial infarction (MI). But has this concept been too narrow in predicting which patients might benefit from treatment with ACE inhibitors? Measurable infarct-expansion with progressive dilatation probably occurs in less than 20% of patients, whereas increase in volume and hypertrophy of the heart as responses to compromised function are likely wherever significant myocardial damage has occurred. Irrespective of infarct expansion, cumulative extensive damage can lead to an inevitable downward spiral with gross ventricular dilatation and death in heart failure. But in the majority of patients after MI a 'new equilibrium' is established in which initial dilatation and subsequently hypertrophy restore adequate function. Is it possible to distinguish patients in whom the cost and inconvenience of long-term therapy with an ACE inhibitor justify the likely benefit from treatment after an MI? The SAVE, AIRE and recent TRACE studies allow a rational approach for the clinician, indicating the effectiveness of these drugs in patients with evidence of impaired ventricular function. However, the prospect that ACE inhibitors prescribed long term might also prevent myocardial reinfarction could justify wider use. Post-MI patients are an easily identifiable high-risk group for a cost-effective programme of secondary prevention. Reinfarction in an already damaged ventricle carries a particularly poor prognosis and its prevention by ACE inhibitors could make a major contribution to the undoubted benefit from these agents. The recently completed TRACE study with its long-term follow-up may help resolve this issue, which is also being investigated in a number of long-term prospective studies in populations at high risk of cardiovascular disease.
Insights
Angiotensin-converting enzyme (ACE) inhibitors benefit patients after myocardial infarction (MI), especially those with impaired ventricular function. Wider use may be justified for preventing reinfarction in high-risk post-MI patients.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Medicine
Background:
- The concepts of infarct expansion and cardiac remodeling following myocardial infarction (MI) have guided treatment strategies.
- Angiotensin-converting enzyme (ACE) inhibitors have demonstrated mortality benefits in post-MI patients.
- The narrow focus on infarct expansion may limit the identification of all patients who could benefit from ACE inhibitors.
Purpose of the Study:
- To evaluate the effectiveness of ACE inhibitors in post-myocardial infarction (MI) patients beyond the traditional infarct expansion concept.
- To determine if ACE inhibitors can be justified for long-term use in a broader post-MI population.
- To explore the potential of ACE inhibitors in preventing reinfarction and improving secondary prevention outcomes.
Main Methods:
- Review of experimental studies and clinical observations on cardiac remodeling post-MI.
- Analysis of major mortality studies (e.g., SAVE, AIRE, TRACE) evaluating ACE inhibitor efficacy.
- Consideration of long-term follow-up data and ongoing prospective studies in high-risk cardiovascular populations.
Main Results:
- While infarct expansion occurs in <20% of patients, ventricular hypertrophy and dilatation are common responses to myocardial damage.
- ACE inhibitors are effective in patients with evidence of impaired ventricular function post-MI.
- Long-term ACE inhibitor therapy may offer benefits in preventing recurrent myocardial infarction (reinfarction).
Conclusions:
- ACE inhibitors provide significant benefits for post-MI patients, particularly those with compromised ventricular function.
- The role of ACE inhibitors in secondary prevention, including reinfarction prevention, warrants broader consideration.
- Post-MI patients represent a high-risk group amenable to cost-effective secondary prevention strategies using ACE inhibitors.