Urinary Methylmalonic Acid in Patients with Acute Myocardial Infarction

Abstract

Objective: To investigate urinary methylmalonic acid (uMMA) levels and their relationship with markers of myocyte necrosis and inflammation in patients with acute myocardial infarction (AMI). Subjects and Methods: The study participants consisted of 80 consecutive patients with AMI and 72 age- and sex-matched consecutive controls. Of the patients, 38 had ST segment elevation myocardial infarction (STEMI) and 42 had non-ST segment elevation. All patients with STEMI underwent fibrinolytic therapy. Routine laboratory tests included troponin-I, creatinine phosphokinase MB (CK-MB), high-sensitivity C-reactive protein (hs-CRP), vitamin B₁₂, folate, homocysteine and methylmalonic acid analyses. uMMA measurements were made by a spectrophotometric method. Results: uMMA levels were significantly higher in patients with AMI than in controls (10.1 vs. 5.2 mmol/mol creatinine, p < 0.001) and higher in patients with anterior MI compared to those with non-anterior MI (18.9 vs. 8.7 mmol/mol creatinine, p < 0.001). In addition, uMMA levels were significantly higher in patients without successful reperfusion compared to those with successful reperfusion. In patients with STEMI, a strong positive association was found between urinary MMA and plasma hs-CRP levels (r = 0.81, p < 0.001), symptom duration (r = 0.91, p < 0.001) and wall motion score (r = 0.60, p = 0.006). More importantly, a strong positive association was observed between uMMA and the size of myocardial infarction in patients without successful reperfusion (for CK-MB r = 0.81, p = 0.013; for wall motion score r = 0.82, p = 0.012). Conclusion: uMMA levels were elevated in patients with AMI and, as such, may be a candidate biochemical indicator of larger infarct size and enhanced inflammation in patients with AMI.