Association of high levels of plasma free dopamine with future coronary events in patients with coronary artery disease

Abstract

Background: There is an intimate relationship between activation of the sympathetic nervous system and myocardial ischemia. This study examined whether plasma levels of dopamine, a precursor of norepinephrine, may provide prognostic information in coronary artery disease (CAD). Methods and Results: Plasma levels of free dopamine were measured by high-performance liquid chromatography in 210 consecutive patients with stable CAD. The patients were prospectively followed up for a period of ≤36 months until occurrence of a clinical coronary event. Coronary events occurred in 37 patients during follow-up. In Kaplan-Meier survival analysis, higher dopamine levels (≥30 pg/ml) resulted in a higher event probability (p<0.01). Multivariate Cox hazards analysis showed that higher dopamine levels were a significant and independent risk factor for future coronary events (hazard ratio 3.3, 95% confidence interval 1.3-8.1, p<0.01). Furthermore, patients with higher dopamine levels had lower left ventricular (LV) ejection fraction and higher levels of brain natriuretic peptide, C-reactive protein, and fibrinogen than those with lower dopamine levels. Conclusions: Plasma levels of free dopamine are increased in association with a decrease in LV function and an increase in inflammatory risk markers. Higher free dopamine levels are an independent risk factor for future coronary events in CAD patients.