Atrial fibrillation is prevalent in dialysis patients. Both ischaemic and haemorrhagic
stroke are common in patients on dialysis with
atrial fibrillation. In the general population,
warfarin is highly effective for prophylaxis of
ischaemic stroke, and though
warfarin use likely increases the risk of intracranial haemorrhage, the absolute increase in risk is small. In the general population, absolute and relative increases in major extracranial
bleeding from
warfarin use are also both modest. In patients on dialysis, the effectiveness of
warfarin as a prophylaxis for
ischaemic stroke and its effects on intracranial or extracranial
bleeding have not been assessed in randomized trials. Cohort studies vary greatly in their estimates of the magnitude of the increased risk of
bleeding from
warfarin use. A single cohort study found rates of intracranial haemorrhage in patients on dialysis with
atrial fibrillation to be in an order of magnitude that is greater than those in the general population with
atrial fibrillation, and that intracranial haemorrhage more than doubled in association with
warfarin use. Basic, translational and limited clinical observations also implicate
warfarin in the pathogenesis of
vascular calcification, which is likely on the causal pathway to patient-important vascular outcomes. Finally, the effect of
warfarin on
ischaemic stroke in three recent large observational studies has been in the direction of harm, no benefit, and modest, non-statistically significant benefit, respectively. We believe that no clear recommendation can be made between three alternative approaches. It is acceptable to withhold or discontinue
warfarin in patients on dialysis, to offer
anticoagulants to all dialysis patients without a
contraindication whose
congestive heart failure,
hypertension, age, diabetes and previous
stroke or transient ischaemic attack (CHADS(2)) score >1 or 2 and to discuss and individualize prophylaxis on a patient-by-patient basis. Randomized trials of new agents are needed in this area.