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Emergency And Acute Medicine – Reperfusion Therapy, Cardiac
Cardiac reperfusion therapy is indicated for patients presenting with ST-segment elevation myocardial infarction (STEMI), which results from acute occlusion of an epicardial coronary artery, usually due to thrombus formation. Early restoration of coronary blood flow reduces myocardial necrosis, morbidity, and mortality. The two primary reperfusion strategies are percutaneous coronary intervention (PCI) and fibrinolytic therapy. In unstable angina (UA) and non–ST-segment elevation myocardial infarction (NSTEMI), early PCI may be considered, but fibrinolytics are not indicated.
Primary PCI is the preferred reperfusion method when it can be performed in a timely fashion. The goal is a door-to-balloon time of 90 minutes from first medical contact in STEMI patients presenting to PCI-capable centers, or within 120 minutes if transfer from a non-PCI facility is required. PCI includes balloon angioplasty, stent placement, and thrombus removal. It achieves higher rates of coronary patency, lower mortality and reinfarction rates, reduced bleeding risk compared with fibrinolytics, and immediate assessment of coronary anatomy. Stent placement decreases early and late luminal loss compared with balloon angioplasty alone. PCI should also be strongly considered within 48 hours for NSTEMI patients after cardiology consultation. Post–cardiac arrest patients may undergo therapeutic hypothermia prior to or during PCI.
Fibrinolytic therapy is indicated in STEMI when PCI cannot be performed within 120 minutes. The goal is a door-to-needle time of 30 minutes. Earlier administration results in greater myocardial salvage. Fibrinolytics are contraindicated in patients with active bleeding, recent hemorrhagic stroke, recent intracranial surgery or trauma, intracranial neoplasm or vascular malformation, severe uncontrolled hypertension, pregnancy, or recent major trauma or surgery.
Adjunctive pharmacotherapy is essential in both PCI and fibrinolytic strategies. Aspirin should be administered immediately. Dual antiplatelet therapy with clopidogrel, prasugrel (contraindicated in prior stroke), or ticagrelor should be added. Anticoagulation with unfractionated heparin, low-molecular-weight heparin (such as enoxaparin), or bivalirudin is indicated in STEMI (whether treated with PCI or fibrinolytics) and in UA/NSTEMI. Low-molecular-weight heparin has more predictable pharmacokinetics and lower bleeding risk compared with unfractionated heparin. Glycoprotein IIb/IIIa inhibitors may be used in patients undergoing PCI but are not indicated in STEMI without PCI. Statin therapy should be initiated early as it reduces subsequent cardiovascular events.
Patients typically present with chest pain described as pressure or heaviness, dyspnea, radiation to the arm, neck, or back, diaphoresis, nausea, vomiting, weakness, palpitations, or syncope. Diagnosis relies on history and ECG findings. STEMI is defined by new ST-segment elevation at the J point in two contiguous leads meeting sex-specific criteria or new ST changes consistent with acute infarction. Left bundle branch block may obscure diagnosis; Sgarbossa criteria can aid interpretation. ECGs may initially be normal and should be repeated if suspicion remains high. Troponin is the preferred cardiac biomarker. Baseline creatinine, hematocrit, and coagulation studies are also obtained. Chest radiograph may be helpful if aortic dissection is suspected.
Prehospital care includes intravenous access, oxygen if hypoxic, cardiac monitoring, sublingual nitroglycerin (unless phosphodiesterase inhibitors were recently used), and aspirin 162–325 mg nonenteric coated. STEMI patients should be transported preferentially to PCI-capable facilities. In the emergency department, continuous cardiac monitoring, blood pressure monitoring, oxygen, nitrates, and analgesia are initiated. β-blockers such as metoprolol may be administered unless contraindicated. Fibrinolytics are given only when PCI is unavailable within the recommended timeframe and no contraindications exist.
All patients undergoing reperfusion therapy require hospital admission to a cardiac catheterization laboratory, intensive care unit, or telemetry unit. No patient considered for reperfusion therapy should be discharged from the emergency department.
The central goal of reperfusion therapy in STEMI is rapid restoration of coronary blood flow, preferably with primary PCI within 90 minutes of first medical contact. If PCI cannot be achieved within 120 minutes, fibrinolytic therapy should be administered within 30 minutes of arrival. Prompt recognition, rapid decision-making, and adherence to time targets are critical determinants of survival.
Cardiac reperfusion therapy is indicated for patients presenting with ST-segment elevation myocardial infarction (STEMI), which results from acute occlusion of an epicardial coronary artery, usually due to thrombus formation. Early restoration of coronary blood flow reduces myocardial necrosis, morbidity, and mortality. The two primary reperfusion strategies are percutaneous coronary intervention (PCI) and fibrinolytic therapy. In unstable angina (UA) and non–ST-segment elevation myocardial infarction (NSTEMI), early PCI may be considered, but fibrinolytics are not indicated.
Primary PCI is the preferred reperfusion method when it can be performed in a timely fashion. The goal is a door-to-balloon time of 90 minutes from first medical contact in STEMI patients presenting to PCI-capable centers, or within 120 minutes if transfer from a non-PCI facility is required. PCI includes balloon angioplasty, stent placement, and thrombus removal. It achieves higher rates of coronary patency, lower mortality and reinfarction rates, reduced bleeding risk compared with fibrinolytics, and immediate assessment of coronary anatomy. Stent placement decreases early and late luminal loss compared with balloon angioplasty alone. PCI should also be strongly considered within 48 hours for NSTEMI patients after cardiology consultation. Post–cardiac arrest patients may undergo therapeutic hypothermia prior to or during PCI.
Fibrinolytic therapy is indicated in STEMI when PCI cannot be performed within 120 minutes. The goal is a door-to-needle time of 30 minutes. Earlier administration results in greater myocardial salvage. Fibrinolytics are contraindicated in patients with active bleeding, recent hemorrhagic stroke, recent intracranial surgery or trauma, intracranial neoplasm or vascular malformation, severe uncontrolled hypertension, pregnancy, or recent major trauma or surgery.
Adjunctive pharmacotherapy is essential in both PCI and fibrinolytic strategies. Aspirin should be administered immediately. Dual antiplatelet therapy with clopidogrel, prasugrel (contraindicated in prior stroke), or ticagrelor should be added. Anticoagulation with unfractionated heparin, low-molecular-weight heparin (such as enoxaparin), or bivalirudin is indicated in STEMI (whether treated with PCI or fibrinolytics) and in UA/NSTEMI. Low-molecular-weight heparin has more predictable pharmacokinetics and lower bleeding risk compared with unfractionated heparin. Glycoprotein IIb/IIIa inhibitors may be used in patients undergoing PCI but are not indicated in STEMI without PCI. Statin therapy should be initiated early as it reduces subsequent cardiovascular events.
Patients typically present with chest pain described as pressure or heaviness, dyspnea, radiation to the arm, neck, or back, diaphoresis, nausea, vomiting, weakness, palpitations, or syncope. Diagnosis relies on history and ECG findings. STEMI is defined by new ST-segment elevation at the J point in two contiguous leads meeting sex-specific criteria or new ST changes consistent with acute infarction. Left bundle branch block may obscure diagnosis; Sgarbossa criteria can aid interpretation. ECGs may initially be normal and should be repeated if suspicion remains high. Troponin is the preferred cardiac biomarker. Baseline creatinine, hematocrit, and coagulation studies are also obtained. Chest radiograph may be helpful if aortic dissection is suspected.
Prehospital care includes intravenous access, oxygen if hypoxic, cardiac monitoring, sublingual nitroglycerin (unless phosphodiesterase inhibitors were recently used), and aspirin 162–325 mg nonenteric coated. STEMI patients should be transported preferentially to PCI-capable facilities. In the emergency department, continuous cardiac monitoring, blood pressure monitoring, oxygen, nitrates, and analgesia are initiated. β-blockers such as metoprolol may be administered unless contraindicated. Fibrinolytics are given only when PCI is unavailable within the recommended timeframe and no contraindications exist.
All patients undergoing reperfusion therapy require hospital admission to a cardiac catheterization laboratory, intensive care unit, or telemetry unit. No patient considered for reperfusion therapy should be discharged from the emergency department.
The central goal of reperfusion therapy in STEMI is rapid restoration of coronary blood flow, preferably with primary PCI within 90 minutes of first medical contact. If PCI cannot be achieved within 120 minutes, fibrinolytic therapy should be administered within 30 minutes of arrival. Prompt recognition, rapid decision-making, and adherence to time targets are critical determinants of survival.
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