Cardiac mortality assessment improved by evaluation of cardiac sympathetic nerve activity in combination with hemoglobin and kidney function in chronic heart failure patients.

UNLABELLED: We examined prognostic interactions among cardiac autonomic function assessed by (123)I-labeled metaiodobenzylguanidine ((123)I-MIBG) activity, hemoglobin, and kidney function in chronic heart failure patients. Anemia, chronic kidney disease, and impairment of cardiac sympathetic function have been shown as determinants of prognosis in heart failure patients, but there has been little information on their synergistic correlations with cardiac mortality.

METHODS: After evaluations of hemoglobin and estimated glomerular filtration rate (GFR), 468 heart failure patients with left ventricular ejection fraction less than 50% underwent cardiac (123)I-MIBG imaging before discharge and were then followed up for a mean interval of 60.5 mo with a primary endpoint of cardiac death. Cardiac (123)I-MIBG activity was quantified using heart-to-mediastinum ratio (HMR) and washout rate.

RESULTS: For 89 fatal cardiac events documented (19.0%), besides New York Heart Association class, multivariate Cox analysis revealed HMR, hemoglobin, and estimated GFR as significant independent determinants, with hazard ratios of 0.215 (P = 0.0129; 95% confidence interval [CI], 0.064-0.718), 0.821 (P = 0.0062; 95% CI, 0.708-0.946), and 0.984 (P = 0.0243; 95% CI, 0.970-0.998), respectively. Receiver-operating-characteristic analysis determined the thresholds for identifying patients at increased risk for cardiac death to be 1.57 for HMR, 11.9 g/dL for hemoglobin, and 46.4 mL/min/1.73 m(2) for estimated GFR. Combining the 4 independent predictors incrementally (P < 0.05) improved prognostic powers maximally up to a global χ(2) value of 97.3 compared with sole or other combinations.

CONCLUSION: Hemoglobin, kidney function, and alterations of cardiac sympathetic nerve activity are independently and synergistically associated with increased cardiac mortality in chronic heart failure patients, together with New York Heart Association functional class.