The prestroke use of vitamin K antagonists for atrial fibrillation - trends over 15 years

BACKGROUND: Effective anticoagulation with vitamin K antagonists (VKAs) is the standard of stroke prevention in patients with non-valvular atrial fibrillation (AF). Although, everyday practice is becoming increasingly guideline-driven, proper anticoagulation is still problematic. We aimed to investigate changes in the use of VKAs for stroke prevention in patients with AF admitted because of acute stroke over a period of 15 years. METHODS: We analysed consecutive acute stroke patients admitted to our centre between June 1995 and December 2010. Data were prospectively collected in a detailed stroke registry. We distinguished between three periods: 1995-2000 (used as reference for comparisons), 2001-2005 and 2006-2010. RESULTS: The AF rate prior to stroke was similar in ischaemic stroke patients (1995-2000: 25%, 2001-2005: 24%, 2006-2010: 24%) but increased in patients with intracerebral haemorrhage (ICH) (6%, 11%, 19%, p = 0.003 since 2006). The proportion of patients with AF using VKAs before stroke has became higher in ischaemic stroke (10%, 16%, 28%, p < 0.001 since 2006) with non-significant trend in ICH (0%, 33%, 45%). The proportion of ischaemic strokes occurring in patients with AF using VKAs with INR < 2 tended to increase over time (58%, 83%, 80.3%). There was also tendency towards increasing proportion of ICHs occurring in patients with AF over treated with VKAs (INR > 3). CONCLUSIONS: The prescription rate of VKA for stroke prevention appears to be improving. However, because of a high proportion of patients on non-therapeutic INR, the proportion of cardioembolic ischaemic strokes remains stable. It may suggest that everyday use of VKAs is still far from optimal.