Urinary methylmalonic acid in patients with acute myocardial infarction

To investigate urinary methylmalonic acid (uMMA) levels and their relationship with markers of myocyte necrosis and inflammation in patients with acute myocardial infarction (AMI).

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 B(12), folate, homocysteine and methylmalonic acid analyses. uMMA measurements were made by a spectrophotometric method.

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).

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.