Prognosis of patients with different peak serum creatine kinase levels after first myocardial infarction

The extent to which patients with low peak serum creatine kinase (CK) at their first myocardial infarction differ from patients with high CK levels in terms of risk for subsequent ischaemic events was investigated in 266 patients who survived the first 48 h from the onset of infarction. All patients were followed up for one year. Four groups were formed based on peak CK less than or equal to 200, 201-400, 401-800 and greater than 800 IU l-1. During follow-up the incidence of mortality was 15% (N = 39), non-fatal re-infarction 9% (N = 23), and angina 53% (N = 140). Hospital mortality was significantly higher (P less than 0.02) in the highest CK-group (16%), but the incidence of non-fatal re-infarction, angina pectoris and late mortality was similar in the four groups. In hospital survivors, ischaemic ST-changes during pre-discharge symptom limited bicycle stress test and multiple vessel disease were equally distributed in all four groups. We conclude that while hospital mortality is directly related to peak CK, there is no relationship between peak CK and late mortality, non-fatal re-infarctions, or recurrent angina. Accordingly, diagnostic and therapeutic procedures in the individual patients are not influenced by the amount of serum CK released during acute infarction.