The diagnostic and prognostic value of first hour glycogen phosphorylase isoenzyme BB level in acute coronary syndrome.

BACKGROUND Evaluating patients with symptoms suggestive of acute coronary syndrome (ACS) is a time consuming, expensive and problematic process in the emergency department. This study aimed to evaluate the diagnostic and prognostic value of glycogen phosphorylase isoenzyme-BB (GP-BB) in ACS. METHODS A total of 72 patients (mean age 61.8 ± 11.6 years) with ACS were enrolled. The ELISA method for determining GP-BB level was performed and considered positive at 〉 10 ng/mL. Duration of angina, type of ACS, demographic features, myoglobin, creatinine kinase and troponin T (cTnT) were also assessed. The cTnT levels eight hours after pain onset was considered the gold standard test for the diagnosis of myocardial infarction. RESULTS The most sensitive biomarker at first hour of admission was GP-BB (95.8%). However, the specificity of GP-BB was low (43.7%). Receiver operating characteristics curve analysis of the GP-BB level for predicting myocardial infarction revealed the area under the curve value as 0.82 (SE 0.04; 95% CI 0.78-0.85). Positive treadmill exercise test (60% vs 17%, p = 0.047), coronary artery disease (CAD; 59% vs 19%, p = 0.007), percutaneous coronary intervention (44% vs 27%, p = 0.031) and 30-day mortality and/or readmission (33% vs 5%, p = 0.028) were found to be higher in unstable angina (UA) patients having GP-BB (+). CONCLUSIONS GP-BB is considerably cardiosensitive at the first hour of admission in patients with ACS, but the specificity of GP-BB is lower and it is elevated in nearly half of the patients with UA. However, in this group, GP-BB predicts significant CAD and the combined end-point of mortality and re-hospitalization.