Early diagnosis and exclusion of acute myocardial infarction using biochemical monitoring. The BIOMACS Study Group. Biochemicals Markers of Acute Coronary Syndromes.

BACKGROUND

The aim was to evaluate whether frequent analysis of creatine kinase MB (CK-MB), myoglobin and troponin T alone or in combination could either confirm or exclude acute myocardial infraction (AMI) within the first few hours after patients were admitted to hospital with chest pain and a non-diagnostic ECG.

METHODS

One hundred and forty-two patients with chest pain (< or = 12 h) and a non-diagnostic ECG were included in the study. Blood samples were obtained every 30 min during the first 3 h and thereafter at longer intervals. Different discriminatory levels and combinations of markers were tested for their ability to detect (n = 59) or exclude (n = 83) AMI during the first 6 h after admission.

RESULTS

No single marker adequately combined high early sensitivity and specificity. However, a combination of myoglobin and CK-MB analyses had a sensitivity at entry of 59%, which increased by 5-10% every 30 min and reached 92% after 2 h and 98% after 6 h with a specificity of 93%. A combination of myoglobin and troponin T analyses showed identical sensitivity but a slightly inferior specificity. In the patients with no AMI it was possible to exclude AMI in 64% within 3 h by using myoglobin and within 6 h in approximately 70% by using CK-MB or troponin T.

CONCLUSIONS

Monitoring of a combination of myoglobin and CK-MB or troponin T will allow confirmation or exclusion of AMI within 3-6 h in almost all patients. This method will have a large impact on the handling of patients with suspected AMI without a diagnostic ECG.