In the absence of an adequate collateral blood supply the myocardium downstream of the coronary thrombosis will infarct unless blood flow can be restored. Infarction occurs over hours and myocardium is potentially salvageable by prompt treatment. The aim is to restore coronary blood flow as quickly as possible. Usually this is attempted by intravenous administration of thrombolytic therapy in the emergency department as soon as the diagnosis is established and any contraindications are excluded. Contraindications are a high risk of bleeding, eg recent surgery, trauma or cerebrovascular accident.
Results are best when therapy is initiated within the first four hours from the onset of chest pain.
The most common drugs used are streptokinase and recombinant human tissue plasminogen activator. Patients are routinely prescribed aspirin and heparin for their antiplatelet and anticoagulant effects. In centres with access to cardiac catheter laboratories an alternative to thrombolytic therapy is acute primary coronary angioplasty. This procedure uses a balloon tipped catheter to mechanically break-up thrombus and dilate underlying stenosis. The decision whether to treat with thrombolysis or angioplasty depends on the patient circumstances and availability of a cardiac catheter laboratory.