Rescue thrombolysis may work even though primary thrombolysis has failed

EDITOR—Gershlick and More discuss the new therapeutic options for myocardial infarction and suggest that patients in whom thrombolysis fails should receive rescue angioplasty.1 We challenge this view and propose that rescue thrombolysis might be considered in cases in which primary thrombolysis has failed.

Two trials have compared rescue angioplasty with conservative management, with equivocal results. 2 3 One trial randomised patients with an occluded artery three hours after the onset of symptoms; it detected a non-significant reduction in mortality in the angioplasty group compared with the group managed conservatively (1/16 v 4/12).2 A similar study with 73 patients who were managed conservatively and 78 who had angioplasty showed that rescue angioplasty performed more than 4.5 hours after the onset of symptoms failed to yield any effect on mortality or on resting ejection fraction.3 Furthermore, it leads to high rates of reocclusion, and an unsuccessful procedure is associated with a high mortality.4

These data suggest that rescue angioplasty has no proved benefit. Even if it is shown to be superior, its availability is limited and in most instances time consuming transfer to a centre with interventional facilities is needed. On the basis of the literature and our own experience we favour rescue thrombolysis instead. A recent trial in 37 patients with acute myocardial infarction with persistent electrocardiographic changes after treatment with streptokinase compared the effect of rescue tissue plasminogen activator with that of placebo. Rescue thrombolysis resulted in a significantly smaller infarct and better ejection fraction.5

Our department runs a home thrombolysis programme, which uses a telephone based electrocardiogram system. The electrocardiogram of symptomatic patients is transmitted from the patient's home to the hospital and anistreplase is given on the spot by the ambulance service if it is indicated. We considered rescue treatment with thrombolysis or angioplasty if the ST segment did not return to normal after 90 minutes of treatment. The decision for either treatment was left to the attending doctor. From 1993 to 1997, 51 patients were given rescue treatment (table). Mortality was similar with rescue angioplasty and thrombolysis but the extent of the myocardial infarction, as estimated from measurement of maximal serum creatinine kinase, was smaller with rescue thrombolysis. Repeated thrombolysis was safe and there was no excess of major bleeding (1.7% v 2.6%).

These data suggest that rescue thrombolysis is at least as effective as rescue angioplasty and should be considered when primary thrombolysis has been unsuccessful.