No.

But these kind of scenarios are exactly what travel insurance is for.

Good luck with your procedure! ^

(Have you asked Expedia if they will credit you the balance in a similar deal with the one offered by Aegean? i.e. Expedia allows you to use the price already paid on another trip (not necessarily on Aegean). Afterall, your contract is with Expedia - not with Aegean. They passed you directly over to Aegean in this case, but ask them specifically, since your contract is with them, what they can do for you).