Subclinical volume overload in stable outpatients with chronic heart failure

Objective The objective of this study was to characterize stable outpatients with subclinical volume overload in chronic heart failure (CHF) by using bioelectrical impedance analysis (BIA) measurements. Methods and results Venous blood sampling and BIA were performed in consecutive CHF patients (n = 58) free from clinical signs of volume overload and treated with oral loop diuretics. Subclinical volume overload was defined as excess extracellular water on BIA. Patients with (n = 34) versus without (n = 24) subclinical volume overload were significantly older (72 +/- 10 versus 65 +/- 9 years; P-value = 0.016), had higher systolic blood pressure (126 +/- 20 versus 114 +/- 17 mmHg; P-value = 0.012), and took angiotensin-converting enzyme inhibitors more often (65% versus 33%; P-value = 0.032). Dyspnoea symptoms were similar among both groups. Subclinical volume overload was associated with low serum albumin (P-value = 0.014) and protein levels (P-value = 0.041). In contrast, serum sodium levels (141 +/- 3 versus 139 +/- 2 mEq/L; P-value = 0.033) but not chloride levels (99 +/- 14 versus 101 +/- 3 mEq/L; P-value = 0.980) were significantly higher in patients with versus without subclinical volume overload, respectively. The former versus latter group also demonstrated lower plasma aldosterone levels [276 (195-475) versus 400 (306-717) ng/L, respectively; P-value = 0.032]. Conclusions Subclinical volume overload assessed by BIA in stable CHF is associated with low serum protein levels, increased serum sodium but not serum chloride, as well as decreased neurohumoral activation.