The partial correction of anemia with recombinant human erythropoietin (rHuEpo) is frequently associated with an increase in arterial pressure and could oppose the beneficial effect of anemia correction on myocardial function. In order to analyze the influence of rHuEpo therapy on the vessels and the heart, we performed systemic and regional hemodynamics studies in 11 hemodialysis patients before and 10 to 35 weeks after initiation of rHuEpo therapy, when hemoglobin concentration was 6.8 +/- 0.9 and 10.6 +/- 0.66 g/dl (mean +/- SD), respectively. The mean arterial pressure remained unchanged during this period (88 +/- 21 vs. 88 +/- 15 mm Hg). Echocardiographic study showed that rHuEpo treatment led to a decrease in left ventricular end-diastolic diameter (4.9 +/- 0.5 vs. 5.1 +/- 0.6 cm; P less than 0.03), left atrial diameter (3.22 +/- 0.30 vs. 3.43 +/- 0.33; P less than 0.03), and left ventricular mass index (109.8 +/- 30.6 vs. 133 +/- 30.8 g/m2; P less than 0.05). Left ventricular ejection volume decreased from 86 +/- 24 to 75 +/- 19 ml (P less than 0.03) and heart rate from 76 +/- 9 to 70 +/- 10 beats/min (P less than 0.05). Cardiac index decreased from 4715 +/- 700 to 3635 +/- 444 ml/min/m2 (P less than 0.01) and peripheral resistances rose from 1480 +/- 162 to 1943 +/- 250 dynes.sec.cm-5.m2 (P less than 0.01). Fractional ejection and mean circumferential fiber shortening remained unchanged. The treatment with rHuEpo did not change the aortic diameters.(ABSTRACT TRUNCATED AT 250 WORDS)