Thrombolysis: state of the art.

Abstract

Thrombolytic treatment and aspirin will save about 50 in 1000 patients treated for acute myocardial infarction, but with a risk of cerebral or other serious bleeding in two to three in every 1000. Early treatment (< 4 h) about halves mortality; the benefits decline with time but are clearly proven up to 12 h from onset. Benefit is best and risk least when there is ST elevation and bundle branch (BB) block on the initial ECG. Hypotension is not a contraindication. There is no clear benefit from treatment of patients with ST depression, T wave change or a normal ECG. Streptokinase (SK), tissue plasminogen activator (tPA) or APSAC are equally effective with no mortality benefit for any of the drugs. SK is safer, particularly in older or more hypertensive patients. tPA is reserved for patients who have received SK during the previous year, when high antibody titres may neutralize its effect on a second myocardial infarction (MI). Heparin (either i.v. or high dose S/Q) added to aspirin may confer some small additional benefit, but at the cost of significantly increased risk of bleeding. It should be reserved for high risk patients. Routine angioplasty is unhelpful. Investigation should be reserved for patients with continuing symptoms or ECG evidence of ischaemia, at rest or after stress testing. The benefits of thrombolysis are seen at all ages, in both sexes, and whatever the site of the MI. Aspirin 75-100 mg daily should be continued long-term.