Blokhin will miss the match after undergoing surgery to remove a blood clot from a carotid artery, but has already indicated he will leave the national team after next week's game against Montenegro to return to Dynamo Kiev.
Pyatov said: "Oleg Blokhin is our head coach and we want him to recover quickly and return to us.
"Now we are thinking about the matches ahead, not who is going to be our next head coach.
"Currently we have a coach. Therefore we are not worried, and we are well prepared and well adjusted for the game against Moldova."
Ukraine's excellent performance in their opening Group H draw against England at Wembley will give them plenty of encouragement against the Moldovans, who remain pointless and goalless after their first two games.
But Blokhin's temporary replacement Andriy Bal has insisted his team must not be complacent, warning: "Moldova have some very good and experienced players. You do not get into a national team if you are a bad player."