Effects of vitamin K antagonist on aortic valve degeneration in non-valvular atrial fibrillation patients: Prospective 4-year observational study

Background The prevalence of atrial fibrillation (AF) is high in elder subjects. Our previous observational study suggested that vitamin K antagonist (VKA) promotes aortic valve degeneration, a principal cause of aortic stenosis in the elderly, and that angiotensin receptor blocker (ARB) attenuates its progression. This study aimed to prospectively investigate these observations in non-valvular AF patients. Methods Of enrolled 430 patients with calcification on no or one aortic valve leaflet, all of the planned 4-year follow-up data were obtained in 122 non-valvular AF patients treated with warfarin (warfarin group) and 101 patients with cardiovascular diseases and without AF and prescription of warfarin (non-warfarin group). Results Despite higher atherosclerotic risks in the non-warfarin group, 2 or 3 newly calcified leaflets emerged during 4 years in 18.0% of patients in the warfarin group and in 6.9% in the non-warfarin group (p = 0.014). Aortic valve area (AVA) did not significantly change in the non-warfarin group during the follow-up, but tended to decrease in the warfarin group (p = 0.057). Non-vitamin K antagonist oral anticoagulant got available in Japan after this study started, and warfarin was discontinued in 15 patients of the warfarin group. The reduction of AVA was significant in the remaining 107 patients on the continuous warfarin treatment (p = 0.002). The effects of ARB on AVA were obscure. Conclusion Major bleeding associated with VKA is well recognized. This study suggests that the development of aortic valve degeneration is another risk of long-term use of VKA in non-valvular AF patients with no or mild aortic valve degeneration.