Editor—Lim and Shiels state that pooled data suggest patients do not benefit from rescue angioplasty after failed thrombolysis and that their outcome is adversely affected when interventional techniques fail to open the vessel affected by the infarct.1 They also state that “vigorous clinical assessment” is required before a patient can be classified as high risk after thrombolytic treatment to prevent misinterpretation of signs such as hypotension and sinus tachycardia. Both points should be addressed.
Firstly, the only large scale randomised trial comparing rescue angioplasty with conservative treatment for failed thrombolysis found a significant reduction in the incidence of death or severe heart failure among patients in the rescue angioplasty group (6% v 17%, P=0.05).2 Additionally, the trial was performed without the use of abciximab, a glycoprotein IIb/IIIa inhibitor shown to be beneficial in high risk angioplasty without increasing the risk of haemorrhage.3 The trial also did not incorporate regular intra-aortic balloon pumping, a treatment shown to be effective in maintaining arterial patency after rescue angioplasty.4 Thus, rescue angioplasty using the modern adjunctive treatments now available might offer more benefit to high risk patients than could be shown in the trial, although further trials are needed.
Secondly, while clinical assessment is clearly important, electrocardiography can be used to identify high risk patients after thrombolytic treatment for acute myocardial infarction. Purcell et al found 18.2% mortality in unselected patients with acute myocardial infarction and <50% resolution of ST segment elevation in the worst lead 60 minutes after the initiation of thrombolytic treatment.5 Mortality in the group with ⩾50% ST segment resolution was just 1.3%. Thus, in Lim and Shiels’s example of a dominant right coronary artery occlusion, the degree of ST segment resolution after thrombolytic treatment is equally as important in risk stratification as the clinical examination, particularly if signs such as hypotension and sinus tachycardia are, as the authors suggest, regularly misinterpreted as indicating a patient at high risk of further adverse events.
References
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