Yamamoto K, et al. - The intention of the authors was to explore the effects of vitamin K antagonist (VKA) on aortic valve degeneration in non-valvular atrial fibrillation (AF) patients. The observation made was that major bleeding associated with VKA was well recognized. The development of aortic valve degeneration served as another risk of long-term use of VKA in non-valvular AF patients with no or mild aortic valve degeneration.