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Chapter 17. Thrombolytic Therapy

Which of the following most strongly suggests the failure of fibrinolytic therapy to achieve reperfusion?

A. >50% residual ST-segment elevation

B. Occurrence of ventricular tachycardia or ventricular fibrillation

C. Cardiogenic shock

D. Lack of complete relief of chest discomfort

The correct answer is A

A number of factors have been identified as being predictive of successful coronary reperfusion with fibrinolytic therapy, including the reduction and/or relief of chest pain, resolution of ST-segment elevation, and the presence of reperfusion arrhythmias. Conversely, >50% residual ST-segment elevation, ongoing chest discomfort, and the absence of reperfusion arrhythmias are indicative of reperfusion failure. The presence of cardiogenic shock is correlated with the amount of myocardium at jeopardy. Complete relief of chest discomfort does not always occur with coronary reperfusion.

Which of the following approaches is associated with the greatest reduction in mortality in the patient <75 years of age who fails to reperfuse within 90 to 120 minutes following fibrinolytic therapy?

A. Administration of a second dose of fibrinolytic therapy

B. Administration of a platelet glycoprotein IIb/IIIa inhibitor

C. Transfer of the patient to a percutaneous coronary intervention (PCI)-capable hospital for rescue PCI

D. Administration of enoxaparin by intravenous (IV) bolus and subcutaneous injection

The correct answer is C

The REACT study demonstrated the superiority of a strategy of immediate transfer of the patient for primary PCI compared with repeat fibrinolysis or conservative therapy. Several studies, including the GUSTO-V and FINESSE trials, evaluated glycoprotein IIb/IIIa therapy in conjunction with fibrinolysis in ST-segment elevation myocardial infarction (STEMI), but not as rescue therapy. Furthermore, these trials were negative. Enoxaparin, including dose adjustment based on age, proved superior to heparin as an adjunct to fibrinolytic therapy in the EXTRACT-TIMI 25 study when given in conjunction with the fibrinolytic agent, not in the context of reperfusion failure.

The time window of benefit of primary PCI in patients with cardiogenic shock extends to what duration?

A. 24 hours from symptom onset

B. 48 hours from symptom onset

C. 24 hours from the onset of shock

D. 48 hours from the onset of shock

The correct answer is B

Patients with shock complicating acute STEMI are a very-high-risk subgroup, with in-hospital mortality of 40% to 80% in reported series. In the SHOCK trial, the benefit of emergency ...

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