2994695 MAVD mixed aortic valve disease 38 2994699 MAVD mean absolute-volume difference 2 2994696 MAVD mixed AVD 2 2994700 MAVD mean AV difference 1 2994701 MAVD mitral and aortic valve disease 1 2994698 MAVD modified assisted venous drainage 1 2994697 MAVD modular anastomotic valve device 1