[Platelet antiaggregation and hemorrhagic risk in hemodialysis]

Although the efficacy of antiplatelet therapy in the prevention of cardiovascular disease in chronic renal failure is not clearly defined, the improvement in cardiovascular disease outcomes in the general population has resulted in its use in dialysis patients. The hemorrhagic risk of hemodialysis patients treated with anti-platelet agents has not been clarified. Our aim was to evaluate the risk of bleeding in hemodialysis patients treated with antiplatelet agents. We assessed haemorrhagic complications (HC) in 190 haemodialysis patients from May 1998 to August 2000. HC was defined an event that required hospitalization and/or blood product transfusion. We evaluated the bleeding events in the haemodialysis patients treated with antiplatelet agents and compare them to those not receiving this therapy to establish the relative risk of bleeding. Uni- and multivariate analyses were conducted to establish the relationships between the haemorrhagic event and the following variables: age, gender, time on dialysis, dialysis membrane (synthetic or cellulosic), systemic anticoagulation during haemodialysis, anaemia (haematocrit), PTH, urea, dialysis efficacy (Kt/V), hypertension, diabetes, use of erythropoietin and antisecretory gastric agents.

81 (42.6%) were treated with antiplatelet agents. Of the 190 patients, 28 (14.7%) had 36 haemorrhagic events (10.3 episodes/100 patient-years); 31 digestive-tract haemorrhages, 4 intracranial and 1 pulmonary. Twenty (24.7%) of patients treated with antiplatelet agents had 16.2 episodes/100 patient-years and 8 (7.3%) without this therapy had 6 episodes/100 patient-years (p < 0.01). In the multivariate analysis the antiplatelet therapy remained associated with higher probability of having a haemorrhagic complication (OR 3.8; CI 95%: 1.52-9.76, p = 0.004). Older age (OR 1.03; CI 95%: 1-1.06, p = 0.043), anaemia (OR 0.91; CI 95%; 0.84-0.9, p = 0.027) and hypertension (OR 2.99; CI 95%: 1.05-8.48, p = 0.039) remained associated with the risk of bleeding. 88.2% of patients that had a digestive-tract haemorrhage with antiplatelet therapy were receiving an antisecretory agent (histamine H2-receptor antagonist or a proton-pump inhibitor).

1) dialysis patients with antiplatelet therapy had a higher haemorrhagic risk. The relative risk of bleeding was more than three times that of the dialysis population without antiplatelet therapy, and 2) older age and hypertension were associated with the haemorrhagic risk. Optimal correction of anaemia was associated with less probability of bleeding.