title: Reply.
authors.affiliation: Erasmus Medical Center, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands.
authors.forename: Robert M A
authors.initials: RM
authors.lastname: van der Boon
authors.affiliation: Erasmus Medical Center, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands.
authors.forename: Ron T
authors.initials: RT
authors.lastname: van Domburg
authors.affiliation: Erasmus Medical Center, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands. Electronic address: p.dejaegere@erasmusmc.nl.
authors.forename: Peter P T
authors.initials: PP
authors.lastname: de Jaegere