Fibrinolytic therapy in patients with ST-elevation myocardial infarction

Abstract

ST-elevation myocardial infarction (STEMI) is related to acute occlusion of a coronary artery by a fibrin-rich thrombus. Early reperfusion in STEMI reduces infarct size and improves prognosis. Acute reperfusion may be achieved with percutaneous coronary intervention (PCI) and/or fibrinolytic agents. When performed in a timely manner, primary PCI is the preferred method of reperfusion; however, due to logistic reasons, including lack of PCI-capable hospitals and delay in the first medical contact-to-balloon time, this simplified approach lacks universal applicability. Due to clinical efficacy and the ease of administration, fibrinolysis is still an important reperfusion modality in patients with STEMI who cannot have primary PCI within guideline-recommended time. This review focuses on the role of fibrinolysis in patients with STEMI.

Keywords::

• fibrinolysis
• percutaneous coronary intervention
• pharmacoinvasive strategy
• prehospital
• ST-elevation myocardial infarction

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Fibrinolysis is an important mode of reperfusion in patients with ST-elevation myocardial infarction (STEMI) when primary percutaneous coronary intervention (PPCI) cannot be performed within guideline recommended time.

• In patients with STEMI presenting to non-PCI-capable hospitals, If first medical contact to PPCI delay is expected to be >120 min, fibrinolysis should be started within 30 min of hospital arrival followed by immediate transfer to a PCI-capable hospital.

• The bolus fibrinolytic agents do not have better efficacy than the accelerated tissue plasminogen activator (tPA), but reteplase and tenecteplase have the similar efficacy to tPA. These agents, especially tenecteplase, are currently used as standard fibrinolysis because they can be easily administered.

• In patients with STEMI, prehospital diagnosis is required and should be combined with field triage directly to cardiac catheterization laboratory in PPCI centers if available, bypassing local hospitals, coronary care units and emergency centers.

• The time taken for transportation by emergency medical services (EMSs) to the hospital is an opportunity to reduce total ischemic time through active prehospital patient evaluation and prehospital fibrinolytic administration by trained EMSs.

• Fibrinolytic therapy is more effective within first few hours after STEMI occurs. Optimal balance between safety and efficacy in STEMI patients who are not able to undergo immediate PPCI can be achieved by using pharmacoinvasive strategy. This was recently confirmed by the Strategic Reperfusion Early After Myocardial Infarction trial.

• One of the strategies to achieve the goal of total ischemic time <120 min will be prehospital diagnosis and initiation of reperfusion with reduced dose of fibrinolytic agents immediately at the scene by trained EMSs providers acting under protocol, followed by urgent infarct artery PCI after the patient is transported. Randomized clinical trials need to be conducted to further investigate the efficacy and safety of this approach.

• Intracranial hemorrhage is the worst bleeding complication of fibrinolytic therapy, especially in elderly, patients with weight <70 kg, women and those with hypertension on admission. Although some data show that fibrinolytic therapy may offer some benefits even in elderly patients, more randomized clinical trials evaluating the efficacy and safety of fibrinolytic agents in elderly are required.

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