100 QUESTIONS IN CARDIOLOGY

22 What medical treatments of unstable angina

are of proven benefit?

Diana Holdright

The treatment of unstable angina is dictated by the underlying

pathophysiology, namely, rupturing of an atheromatous plaque

and secondary platelet aggregation, vasoconstriction and thrombus

formation.

Anti-ischaemic therapy

Nitratesrelieve ischaemic pain but there is no evidence of

prognostic benefit from their use.

Calcium antagonists are effective anti-ischaemic and vasodilator

drugs. However, in the absence of beta blockade, nifedipine

should be avoided due to reflex tachycardia. Verapamil and

diltiazem have useful rate-lowering properties, but should be

used cautiously in patients with ventricular dysfunction and

patients already taking beta blockers.

Beta-adrenoceptor blockers are an important treatment in unstable

angina, not only relieving symptoms but also reducing the

likelihood of progression to infarction and cardiac death. There is

no evidence to favour one class of beta blocker over another.

Antithrombotic therapy

Aspirin has an important and undisputed role in the treatment of

unstable angina, reducing the risk of fatal/non-fatal MI by 70%

acutely, by 60% at 3 months and by 52% at 2 years.^1 A first dose of

160-325mg should be followed by a maintenance dose of 75mg

daily.

Ticlopidineand clopidogrel, antagonists of ADP-mediated platelet

aggregation, are possible alternatives in patients unable to take

aspirin, although ticlopidine has important side effects and trials

using clopidogrel have yet to be completed (e.g. CURE study).