Atrial fibrillation (AF) is fairly prevalent in patients with end stage renal disease (ESRD) with the prevalence estimated to be 3.8 - 27%. While it is reported that patient with peritoneal dialysis (PD) has a lower incidence of AF as compared to patient with haemodialysis (HD), the risk is still substantially higher than in the general population. AF is a known risk factor for embolic stroke and stroke causes significant morbidity and mortality. Anticoagulation in an effective treatment for the prevention of stroke in the general population. However, this is less clear in the ESRD populations. Despite the risk of stroke is higher than general population, the management of AF in patients with ESRD remains controversial with limited and often conflicting result for the use of traditional vitamin K antagonists. It also showed an increased risk of bleeding with the use in ESRD patients. With the advent of direct oral anticoagulants (DOACs), there is growing interest in advocating their uses and studies have been done to assess their safety profile. In fact, several randomized control trials are being performed. However, these studies are done in HD populations and there is no data for PD populations at all so far. Given the physiology of drug clearance is different between the two renal replacement modalities, the investigators purpose to assess the pharmacokinetics and the safety profile of Apixaban in PD populations. By establishing the pharmacokinetics and its safety profile, apixaban may be a more attractive option for anticoagulation for AF or other venous thrombotic indications in PD population.