Abstract
BACKGROUND: The pathophysiological condition between heart failure (HF) with preserved left ventricular ejection fraction (LVEF; HFpEF) and non-HFpEF is different. To elucidate the prognostic value of monocytes, as representatives of the innate immune system, we examined the association between peripheral monocyte counts and future HF-related events in patients with HF. METHODS AND RESULTS: A total of 678 patients with HF referred for hospitalization was enrolled. These patients were categorized into 2 groups according to LVEF: HFpEF, and non-HFpEF. Based on the median monocyte values, we then defined the high monocyte group as having peripheral monocyte counts ≥363/mm(3) in patients with non-HFpEF, and as peripheral monocyte counts ≥322/mm(3) in patients with HFpEF. There were 200 patients with non-HFpEF and 478 with HFpEF. Based on receiver operating characteristic analysis, patients with non-HFpEF who were in the high peripheral monocyte group had a significantly higher risk of HF-related events compared with those in the low peripheral monocyte group. In contrast, the high and low peripheral monocyte groups for patients with HFpEF had no significant difference in HF-related events. Multivariate Cox hazard analysis identified high peripheral monocyte counts as an independent and significant predictor of future HF-related events only in patients with non-HFpEF. CONCLUSIONS: High peripheral monocyte count was an independent and incremental predictor of HF-related events in non-HFpEF, rather than in patients with HFpEF.