the echo itself cant control the anova. as far as im aware the only bluetooth profiles it really uses are those used for speakers like a2dp etc... and i dont believe the bluetooth hardware of the echo is even exposed to alexa developers.
i know that some guy made a bluetooth bridge for the anova in python though, and it technically would in fact be possible to get an echo to control a device running his bluetooth bridge software. something like an odroid or raspi with a bt radio running the anova bt bridge software as well as some kind of webserver to accept commands from the internet, triggered by alexa, would allow you to do this. however since it involves the user doing super tricky stuff in their own environment, it's not going to really be something easily integrated into the "published" anova skill, it'd have to be a user's own private development skill.