[Is the plasma ANP level an index of volume expansion in dialysis patients?]

Fluid overload is a frequent complication in anuric patients undergoing hemodialysis (HD) or hemofiltration (HF). Elevated ANP plasma concentrations are associated with overhydration or congestive heart failure (CHF). After intensive ultrafiltration in 18 HD patients with high ANP levels at the end of HD, ANP values normalized (28 +/- 4 fmol/ml) in 11 patients (group A), suggesting previous volume overload, whereas ANP remained elevated (126 +/- 31 fmol/ml) in seven patients (group B). Left ventricular ejection fraction by radionuclide ventriculography (LVEF) was significantly (p less than 0.01) lower in group B (41 +/- 7%) as compared to normal values in group A (67 +/- 8%). M-mode echocardiography demonstrated left atrial enlargement (53 +/- 3 mm) and pathologic enddiastolic left ventricular diameters (58 +/- 4 mm) in group B, compared to normal dimensions of left atrial (43 +/- 1 mm) and left ventricular enddiastolic diameters (47 +/- 4 mm) in group A. Persisting high ANP concentrations after intensive ultrafiltration in HD patients indicate CHF and require further diagnostic evaluation.