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

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 2 10 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 (>= 30pg/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.