The Utility of Urinary Titin to Diagnose and Predict the Prognosis of Acute Myocardial Infarction

Early detection and management are crucial for better prognosis in acute myocardial infarction (AMI). Serum titin, a component of the sarcomere in cardiac and skeletal muscle, was associated with AMI. Thus, we hypothesized that urinary N-fragment titin may be a biomarker for its diagnosis and prognosis. Between January 2021 and November 2021, we prospectively enrolled 83 patients with suspected AMI. Their urinary N-fragment titin, serum high-sensitivity troponin I (hsTnI), creatine kinase (CK), and creatine kinase-MB (CK-MB) were measured on admission. Then, urinary titin was assessed as diagnostic and prognostic biomarker in AMI. Among 83 enrolled patients, 51 patients were diagnosed as AMI. In AMI patients who were admitted as early as 3 h or longer after symptom onset, their urinary titin levels were significantly higher than non-AMI patients who are also admitted 3 h or longer after symptom onset (12.76 [IQR 5.87-16.68] pmol/mgCr (creatinine) and 5.13 [IQR 3.93-11.25] pmol/mgCr, p = 0.045, respectively). Moreover, the urinary titin levels in patients who died during hospitalization were incredibly higher than in those who were discharged (15.90 [IQR 13.46-22.61] pmol/mgCr and 4.90 [IQR 3.55-11.95] pmol/mgCr, p = 0.023). Urinary N-fragment titin can be used as non-invasive early diagnostic biomarker in AMI. Furthermore, it associates with hospital discharge disposition, providing prognostic utility.