Can I subsitute crushed tomatoes with tomato puree?
You've substituted tomato for tomato (both precooked). It might not be exactly what you were intending to make but it will be fairly similar (very similar in flavour, less so in texture). It will certainly be edible. You might want to adjust the quantities of other liquid ingredients, or cook for a little longer before asking the pasta (if that's an option at this stage) just to thicken it a little. 

This is the sort of substitution some people might choose to make to suit their tastes so you don't need to worry about it.