Human heart-type cytoplasmic fatty acid-binding protein in serum and urine during hyperacute myocardial infarction

We have previously reported that serum and/or urinary human heart-type cytoplasmic fatty acid-binding protein (HH-FABP c) can be used as an early indicator of myocardial injury (Clin Biochem 1991; 24: 195–201). To confirm the usefulness of HH-FABP c as an early diagnostic indicator of acute myocardial infarction (AMI), its serum and urinary levels were measured in samples obtained within 6 h after the onset of acute coronary syndrome related symptoms. Samples were collected from 97 patients, who were composed of 63 with AMI, 24 with unstable angina and 10 with chest pain syndrome. The positivity of serum and urinary HH-FABP c and cardiac creatine kinase isozyme MB (CK-MB) was analyzed in these samples. Serum HH-FABP c levels in AMI were above normal in 91.4% ( 64 70 ) of the samples tested within 3 h of the onset of symptoms and in 100% ( 111 111 ) of those tested at 3–6 h. Elevated urinary HH-FABP c levels in AMI were obtained in 88.9% ( 8 9 ) of samples at 0–3 h and in 75% ( 6 8 ) at 3–6 h. CK-MB activity in AMI was positive in 20% ( 8 40 ) and 66.3% ( 53 80 ) of serum samples at 0–3 h and 3–6 h, respectively. HH-FABP c was always positive when a serum sample was positive for CK-MB. Serum HH-FABP c at 0–6 h in chest pain syndrome and in unstable angina were positive in 17.8% ( 5 28 ) and 56.7% ( 34 60 ), respectively. The elevated HH-FABP c in serum and urine was noted much earlier than that of CK-MB during the hyperacute phase of AMI. HH-FABP c showed high positive value in unstable angina, but it was low in normal coronary patients having chest pain. However, HH-FABP c level in unstable angina and chest pain syndrome was lower than that of AMI. Thus, HH-FABP c may be a valuable indicator for the diagnosis of hyperacute myocardial infarction.