Immediate Management

ACS are essentially due to an imbalance between coronary supply and myocardial demand of oxygen and nutrients.

Therapy (pharmacological and interventional) is aimed at redressing this imbalance.

Pharmacological treatment can be divided into anti-thrombotic and anti-ischaemic:

• Anti-thrombotic agents inhibit intracoronary thrombosis through effects on the clotting cascade or via anti-platelet mechanisms
• Anti-ischaemic agents decrease myocardial oxygen demand through negative inotropic or chronotropic actions or through vasodilation

The image shows the reduction of blood supply to the myocardium caused by varying degrees of coronary occlusion.

General Measures – ‘Cardiac First Aid’

NICE recommends offering aspirin as soon as possible to all people with unstable angina or non‑ST‑segment elevation myocardial infarction (NSTEMI) and continue indefinitely unless contraindicated by bleeding risk or aspirin hypersensitivity. This should initially be a loading dose of 300mg aspirin, followed by 75mg once daily.  The only contraindication to the initial loading dose is clear evidence of allergy [3].

Patients should be offered opiate analgesia (morphine or diamorphine) and should be given supplementary oxygen to a target saturation level of >93%.  Excessive oxygen can increase infarct size, and should be avoided.  GTN should also be offered as adjunctive analgesia. It is also important to avoid uncontrolled hyperglycaemia.  Manage hyperglycaemia in people admitted to hospital for an acute coronary syndrome by keeping blood glucose levels below 11.0 mmol/litre while avoiding hypoglycaemia. In the first instance, consider a dose-adjusted insulin infusion with regular monitoring of blood glucose levels.