Purpose: The purpose of this study was to assess the usefulness of lactate and C-reactive protein as early markers of acute myocardial infarction (AMI) in conjunction with established markers, such as creatine phosphokinase (CPK)-MB and troponin I.
Methods: The study population consisted of all patients admitted with suspected AMI regardless of age, race, gender, or comorbid conditions. All patients in cardiac heart failure or cardiogenic shock were excluded. Lactate and C-reactive protein were drawn at admission, and then at 2 and 4 hours, respectively. The positive and negative predictive values of these markers were calculated in relation to the primary outcome measure.
Results: A total of 62 patients were enrolled in the study. Of those, 18 patients had documented AMI and all underwent thrombolysis, thrombolysis with angioplasty, or stent placement. The lactate was measured at 2 and 4 hours, and lactate levels correlated with CPK and CPK-MB, in addition to troponin I. In our cohort, lactate had a sensitivity of 75% and a specificity of 95.5%, with a positive predictive value of 85.7% and a negative predictive value of 91.3%.
Conclusion: As an inexpensive and readily available marker for AMI, lactate seems to be reliable and could be used in an emergency setting to facilitate the decision-making process for chest pain syndrome. It would be a helpful adjunct on whether the patient can be safely discharged or should be promptly admitted.