Abstract 3484: High Plasma Levels of Endogenous Free Dopamine Predict an Adverse Outcome in Patients with Heart Disease and Chronic Kidney Disease
Sympathetic activity is heightened in chronic kidney disease (CKD). The increased sympathetic activity is a risk of future cardiovascular disease (CVD) events. Dopamine, a precursor of norepinephrine biosynthesis, is metabolized in the kidney and excreted into urine, and its plasma levels are increased in renal dysfunction. Thus, we examined whether plasma levels of endogenous dopamine may be related to future CVD events in patients with CKD. A total of 840 patients in stable condition with chronic heart disease (622 patients with ischemic heart disease and 218 with non-ischemic heart disease) (586 patients with GFR ≥ 60 ml/min/1.73 m2 [normal/mild CKD]; 153 patients with 60 > GFR ≥ 30 [moderate CKD]; 101 patients with 30 > GRF [advanced CKD]) were prospectively followed-up for 5 years or until one of the following CVD events: cardiac death, non-fatal myocardial infarction, unstable angina pectoris requiring unplanned revascularization, worsening heart failure requiring hospitalization, or stroke. Plasma levels of endogenous free dopamine at entry were measured by high-performance liquid chromatography. Patients with a higher stage of CKD had higher dopamine levels than patients with a lower stage (63.0 ± 5.5, 45.0 ± 5.1, and 26 ± 1.2 pg/mL, respectively, ρ = 0.54, p < 0.0001 Spearman rank correlation test). During the follow-up period, 233 patients had CVD events (cardiac death in 54, myocardial infarction in 18, others events in 161) (113 events [19%] in normal/mild CKD, 64 [42%] in moderate CKD, and 56 [55%] in advanced CKD). In patients with moderate CKD and advanced CKD, higher dopamine levels (≥ 40 pg/mL, defined by ROC analysis) were the strongest predictor of CVD events (HR 2.1 and 3.3, 95% CI 1.2 – 3.7 and 1.5 – 7.2, p = 0.006 and 0.003, respectively) in a multivariate Cox hazards analysis using plasma norepinephrine and BNP levels, hypertension, and hyperlipidemia as covariates. In contrast, dopamine levels did not have predictive value in normal/mild CKD (HR 1.2, 95% CI 0.7 – 2.0, p = 0.5). High plasma levels of endogenous free dopamine are a risk factor for future CVD in patients with CKD independently of norepinephrine levels. Increases in plasma endogenous free dopamine levels may serve as a mechanistic link between CKD and CVD.