Effect of increasing serum albumin on plasma D-dimer, von Willebrand factor, and platelet aggregation in CAPD patients

This study was performed to investigate the interrelation between blood albumin level and D-dimer (a marker of intravascular coagulation) and von Willebrand factor (vWF; a marker of endothelial injury) levels or platelet aggregation. Blood levels of albumin, D-dimer, vWF, and C-reactive protein (CRP) and the threshold aggregating concentration (TAC) of ristocetin were measured in 64 continuous ambulatory peritoneal dialysis (CAPD) patients and compared with 36 healthy controls. Twenty-two CAPD patients with albumin levels less than 3.0 g/dL were divided into experimental and disease-control groups. In the experimental group, levels were measured before and after repeated infusions of 20% albumin, 100 mL/d for 7 days. The same parameters were measured in the disease-control group that did not receive the albumin infusion. CAPD patients had higher D-dimer and vWF levels than the healthy controls. There were inverse correlations between albumin and D-dimer (r = -0.48; P < 0.001), vWF (r = -0.29; P < 0.05), or logCRP (r = -0.44; P < 0.001) in CAPD patients. There were positive correlations between logCRP and D-dimer (r = 0.38; P < 0.01) and between logCRP and vWF (r = 0.32; P = 0.01) in CAPD patients. No change was seen in D-dimer, vWF, and CRP levels in either group. The TAC of ristocetin in the 18 CAPD patients was not different from that in the 11 healthy controls (0.55 +/- 0.09 v 0.65 +/- 0.07 mg/mL). There was a correlation between albumin level and TAC in the CAPD patients (r = 0.59; P < 0.01). TAC increased from 0.50 +/- 0.09 to 0.62 +/- 0.13 mg/mL (123% +/- 17%; P < 0.05; n = 6) at the end of the repeated albumin infusions in the experimental group, whereas it did not change in the control group. CRP level did not change in either group. The results of this study indicate that hypoalbuminemia increases platelet aggregability. The observation that the albumin infusion was not associated with changes in D-dimer and vWF despite the inverse correlations suggests that these relationships may be secondary to other factors, such as inflammation.