THE USE OF MYOGLOBIN CARBONIC-ANHYDRASE-III RATIO AS A MARKER FOR MYOCARDIAL DAMAGE IN PATIENTS WITH RENAL-FAILURE

To evaluate the clinical significance of myoglobin and myoglobin/CA II I ratio as a biochemical marker for acute myocardial infarction (AMI) in patients with renal failure, we studied 300 patients admitted to th e hospital with a history of symptoms characteristic of AMI, and 33 re nal failure patients who were undergoing chronic maintenance dialysis treatment and who did not have clinical or electrocardiographic eviden ce of AMI. Fifteen of 300 patients admitted to the hospital had AMI ba sed on the WHO criteria, and a concomitant value of serum creatinine c oncentration (S-Crea) over 140 mu mol/l indicating renal failure. Four teen of these 15 patients (93%) had serum myoglobin concentration over 70 mu g/l and myoglobin/CA III ratio over 2,20 as measured by time-re solved fluoroimmunoassay (TR-FIA); these values were cutoff values for AMI diagnosis. Twenty-two of 300 patients admitted to the hospital ha d S-Crea over 140 mu mol/l in the absence of myocardial injury. Sixtee n of these 22 (73%) patients had increased serum myoglobin concentrati on, but only four of 22 (18%) had myoglobin/CA III ratio over 2,20. A positive correlation between serum myoglobin and CA III concentrations (r(S) = 0.933, P < 0.001) was observed in hemodialyzed patients with chronic renal failure. The values for serum myoglobin/CA III ratio obs erved in this group were similar to those measured in the 22 non-AMI p atients with S-Crea over 140 mu mol/l admitted to the hospital and dif fered statistically from that for patients with AMI (P < 0.001). We co nclude that serum myoglobin, as well as CA III values, are elevated in patients with renal failure, and therefore S-myoglobin can not be use d as a marker for AMI in these patients. Our results suggest that the serum myoglobin/CA III ratio is a reliable AMI marker even in renal fa ilure patients, and therefore provides a tool for AMI diagnosis in thi s patient group. (C) 1997 Elsevier Science B.V.