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[When to begin reperfusion therapy in patients with acute myocardial infarct: in the early phase or whenever?]
1Koronární jednotka Kliniky kardiologie, Institut klinické a experimentální medicíny, Praha.
Insights
Early reperfusion therapy for acute myocardial infarction reduces heart damage and mortality. While delayed treatments have limited benefits, angioplasty may aid left ventricular remodeling, though cost is a barrier.
Area of Science:
- Cardiology
- Emergency Medicine
Context:
- Acute myocardial infarction (AMI) management focuses on early reperfusion therapy.
- Reperfusion aims to restore blood flow to the infarct-related artery, minimizing myocardial necrosis.
Purpose:
- To evaluate the efficacy and timing of reperfusion strategies in acute myocardial infarction.
- To assess the impact of early versus delayed recanalization on patient outcomes and cardiac remodeling.
Summary:
- Early recanalization (within 6 hours) of the infarct-related artery in AMI reduces necrosis, hospital mortality, and one-year mortality, and limits left ventricular expansion.
- Delayed recanalization (within 12-24 hours) offers limited necrosis reduction, with unclear mortality benefits. Percutaneous transluminal angioplasty may improve remodeling but is often impractical.
- Reperfusion injury is a potential drawback, though its impact on mortality requires further investigation.
Impact:
- Optimal timing for reperfusion therapy in AMI is crucial for improving patient survival and cardiac function.
- Understanding the benefits and limitations of delayed reperfusion strategies informs clinical decision-making.
- Percutaneous transluminal angioplasty shows potential for improving left ventricular remodeling in later stages of AMI.
Abstract:
As regards reperfusion therapy in patients with acute myocardial infarction, the general belief today is that early recanalization of the infarct-related artery--using either thrombolytic therapy or direct mechanical thrombolysis with angioplasty, and undertaken within 6 hours since the onset of ischaemia--can reduce the extent of necrosis, will reduce both mortality during hospitalization and one-year mortality, and will favourably limit regional expansion of the left ventricle affected by the infarction. Drawbacks include apparent reperfusion injury to the myocardium with possible impact on patients' mortality within the first 24 hours. The importance of reperfusion injury has not been fully established as yet. Delayed recanalization within 12 hours can only occasionally reduce the extent of necrosis (in specific cases where the development of necrosis has not yet been completed). The effect on patients' mortality remains unclear. While delayed institution of thrombolytic therapy must be considered on a case-by-case basis, it is not contraindicated. It does not seem advantageous to initiate thrombolytic therapy within 12 to 24 hours since the onset of ischemia. In such cases, percutaneous transluminal angioplasty may be more appropriate, but practical considerations and the costs involved render this option virtually unfeasible at present. However, delayed recanalization of the infarct-related artery using the latter method may exert a favourable effect on left ventricular remodeling. It should be noted it is no longer a mechanism of direct myocardial protection, as is the case in the early phase of infarction.