Determining prognosis after acute myocardial infarction in the thrombolytic era

Editor—Beller brings to readers’ attention the fact that routine invasive procedures after acute myocardial infarction offer no significant benefit over that offered by the routine practice of risk stratification with non-invasive methods.1 We are concerned, however, with the blanket statement that high risk patients should have early angioplasty or rescue angioplasty after failed thrombolysis. This technique should be used with caution. A meta-analysis by Ellis et al indicated a mortality of 10.6% after the procedure, either from the disease process or as a direct complication of the procedure.2 Furthermore, this procedure fails in 20% of cases and those failed cases have a mortality of 40%. Vigorous clinical assessment is therefore necessary before a patient is classified as being at high risk. Inadequate optimisation of supportive treatment often leads to signs such as hypotension and sinus tachycardia, which in turn predispose to further chest pain, interpreted as postinfarction angina even in the absence of electrocardiographic changes. Chest crepitations related to aging are often confused with those associated with pulmonary oedema. One prime example is inferior myocardial infarction with right ventricular extension. This is due to an occlusion of a dominant right coronary artery, which carries a relatively good prognosis. Suboptimal fluid replacement and the indiscriminate use of inotropic agents without prior careful assessment of left ventricular function with echocardiography and guidance by Swan-Ganz catheterisation lead to patients being classified as at high risk without having prior or incidental left coronary artery disease. The fact that rescue angioplasty for right coronary artery occlusion is associated with excessive complications3 should lead doctors to question whether this form of intervention is putting a patient’s life at risk, turning a relatively benign course into a fatal one.