Association of asymmetric dimethylarginine levels with treadmill-stress-test-derived prognosticators

Background: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide production. The purpose of this study was to assess the correlation between ADMA and treadmill stress test outcome parameters with known prognostic value, in patients with intermediate risk for coronary artery disease (CAD).

Methods: Study participants were referred for treadmill exercise stress test (EST) due to symptoms of suspected CAD. Participants with prior history of CAD, cerebrovascular events, peripheral artery disease, systemic inflammatory disease or use of anti-inflammatory agents were excluded. ADMA levels were measured before EST.

Results: The study prospectively enrolled 209 individuals (165 males, aged 58.1±10.9). A significant negative correlation was detected between ADMA and maximal exercise time (r=-0.556, p<0.001), metabolic equivalents (METs) (r=-0.555, p<0.001) and Duke treadmill score (DTS) (r=-0.347, p<0.001). Subjects who exercised to ≥10 METs (n=114) had lower ADMA levels than those who achieved <7 METs (n=30) (0.58±0.06 vs 0.87±0.08μmol/L, p<0.001), and those with DTS<5 (n=63) had higher ADMA (0.75±0.19 vs 0.64±0.15μmol/L, p<0.001) compared to those with DTS ≥5 (n=146). In multivariable analysis, ADMA remained an independent predictor of DTS (R(2)=0.210; beta=-10.5; 95% confidence interval -14.9 to -6.2; adjusted p<0.001) and METs (R(2)=0.500; beta -8.5; 95% confidence interval -9.7 to -6.0; adjusted p<0.001) after adjustment for age, BMI, gender, diabetes, smoking status, dyslipidemia, hypertension and family history of premature CAD.

Conclusion: ADMA is correlated to EST parameters with proven prognostic value. This implies that ADMA itself might be a useful prognosticator in patients with suspected CAD.