Effect of nifedipine on changes in fibrinogen and von Willebrand factor in haemodialysis patients treated with recombinant human erythropoietin.

Erythropoietin (EPO) therapy in haemodialysis patients may be associated with the development of hypertension and vascular access thrombosis. Raised levels of fibrinogen and von Willebrand factor have been implicated in the pathophysiology of thrombosis under these circumstances. The effect of nifedipine, used to treat EPO therapy-related hypertension, on levels of fibrinogen and von Willebrand factor antigen (vWf) was studied in a group of 21 EPO-treated haemodialysis patients. Significant increments in both fibrinogen and vWf following EPO therapy were observed in the 13 patients who did not receive nifedipine (fibrinogen (median range), pre-EPO: 3.73 (2.41-6.38) mg/ml, post-EPO: 4.59 (3.03-8.80) mg/ml, P < 0.05; vWf pre-EPO: 183 (118-374)% normal, post-EPO: 253 (124-392)% normal, P < 0.01). Similar changes were not seen in the eight nifedipine-treated patients (fibrinogen, pre-EPO: 3.35 (2.58-6.32) mg/ml, post-EPO: 3.36 (2.69-7.20) mg/ml, P = NS; vWf, pre-EPO: 176 (104-298)% normal, post-EPO: 175 (82-371)% normal, P = NS). These effects were independent of blood pressure control. The use of nifedipine to treat EPO therapy-related hypertension may therefore potentially help to reduce the risk of vascular access thrombosis.