Personally, regardless of situation, I wouldn't apologize for stuttering (not that it's an option anyway). I stutter. That's that. If I was in a wheelchair I wouldn't apologize for not being able to walk. That aside, I think getting right in to it might be best. *Standard getting, then... I have a stutter and it may take me a moment to work through some words. This is more difficult than I thought in trying to make it sound "professional", but I'm still thinking just get right in to it.