Silent cerebral microvascular disease and longitudinal risk of cognitive decline in atrial fibrillation

Abstract Background A relationship between silent stroke and cognitive disorder has recently been suggested in patients with nonvalvular atrial fibrillation (NVAF). This research is an exploratory research study to investigate the occurrence of asymptomatic cerebrovascular disorders with NVAF. Methods The SKAF (Silent cerebral microvascular disease and longitudinal risK of cognitive decline in Atrial Fibrillation) study is a prospective, investigator-initiated, multicenter, observational study of Japanese patients with NVAF aged 60 years or older. We had planned to enroll two hundred NVAF patients with no history of symptomatic stroke or dementia, and an anticoagulant therapy with edoxaban is being performed or an anticoagulant therapy is not being performed, and one hundred patients with sinus rhythm, for comparison. We collected patient characteristics, clinical course, the data of head MRI test and cognitive function test (Montreal Cognitive Assessment (MoCA)) at the baseline and the 24 months follow-up. The primary endpoint was the composite of silent ischemic stroke and micro-bleeding over a 24-month follow-up period. The secondary endpoint was cognitive decline over a 24-month follow-up period. Results The study was started in October 2016, with a planned 2-year recruitment period. As of January 31, 2018, a total of 326 patients were enrolled. Of those, 99 patients with sinus rhythm (SR group) and 214 patients with NVAF (NVAF group) were analyzed (male, 193 (62%) patients; age, 72.2±6.5 years). 156 of 195 (80%) patients with NVAF received the anticoagulant therapy with edoxaban. There was no significant difference of the primary composite for the endpoints between two groups (17.4% versus 17.4%; p=1.00). The incidences of silent ischemic stroke and micro-bleeding in SR and NVAF groups over a 24-month follow-up period were 9.3% and 10.8% (p= 0.833), and 8.1% and 9.2% (p=1.00), respectively. The NVAF group exhibited a significantly larger decline in cognition changes in MoCA score than SR group (-0.830 versus 0,000; p=0.0131). Notably, NVAF was found to be associated with cognitive decline. Conclusion The SKAF registry provided an equivalent risk of silent cerebral microvascular disease in patients with SR and NVAF. Clinically, NVAF had an impact on cognitive decline.