First Online: 25 June 2018
Conflict of interest
: J. Baan receives a research grant from Edwards Lifesciences and is proctor for Edwards Lifesciences. F. van Kesteren, M.S. van Mourik, E.M.A. Wiegerinck, J. Vendrik, J.J. Piek, J.G. Tijssen, K.T. Koch, J.P.S. Henriques, J.J. Wykrzykowska, R.J. de Winter, A.H.G. Driessen, A. Kaya, R.N. Planken and M.M. Vis declare that they have no competing interests.