Acute myocardial infarction: failed thrombolysis
- South Cleveland Hospital, Middlesbrough, UK
- Dr MA de Belder, South Cleveland Hospital, Marton Road, Middlesbrough TS4 3BW, UKmdb.sch.heart{at}onyxnet.co.uk
Reperfusion strategies in the early phase of treatment of acute myocardial infarction aim to rapidly normalise and maintain tissue perfusion. Primary angioplasty is probably the best current treatment but it can only be applied to a minority of patients and has its own problems. Thrombolysis remains the most commonly used treatment. It has well demonstrated benefits, saving lives and reducing left ventricular damage, but is far from perfect.1 The mega-trials have sent a clear message that the greatest benefits are seen with patients who are treated early. Clinical efforts have therefore been concentrated on educating the population to heed the early symptoms, encouraging rapid admission to hospital (sometimes with thrombolytic treatment being administered in the ambulance) and minimising “door to needle” times. Continuous and widespread use of audit increases the number of patients treated and the speed with which treatment is administered.
Key points
-
Failure of thrombolytic treatment at 1–2 hours is associated with a 30 day mortality > 15%
-
The diagnosis of failed thrombolytic treatment is currently best achieved with repeat 12 lead ECGs
-
The absence of chest pain 1–2 hours after the onset of thrombolytic treatment does not imply reperfusion
-
Conversely, the presence of chest pain does not imply failure to achieve TIMI-3 flow at coronary angiography
-
Angiographic coronary patency at 60–90 minutes is achieved more frequently after t-PA or r-PA compared with streptokinase, but there is no significant difference in vessel patency at 6–12 hours between these agents
-
Angiographic TIMI-3 flow is achieved in only 25–50% of patients with modern thrombolytic agents at 90 minutes after onset of treatment
-
Normal tissue perfusion is achieved in < 40% of patients treated with current thrombolytic agents
-
Repeat thrombolysis has not been shown to reduce mortality associated with failure of initial treatment
-
Rescue angioplasty has been shown to confer …
