I would say no.
1: The swap space does not use the same concept of free space as filesystem
2: what matter is that you always keep at least 25% free space on your SSD (this value was given to me by Sandisk representative on the phone), to allow proper work of wear levelling.
=> as long as the disk has spare clusters to work with, and to perform WL, it does not really matter if 5% of your disk is never trimmed, or continusouly re-written: even when YOU rewrite the same logical or physical sectors, WL will use different clusters anyway, when you write large enough blocks.
The question remains unanswered if you are using a whole disk for swapping. A whole disk used for swap may suffer premature aging, if never trimmed.
The other question is: does the swap driver support discard ? ext3/ext4 do.
Maybe, if your swap occupies a significant % of the disk, if you can, you could discard/trim the swap space during shutdown: if you can, after killing all services, do swapoff, and find a way to discard the swapspace (since I am not an expert, and to not leave the question unanswered, I would propose to mkfs.ext3, fstrim, mkswap again - there are probably other better solutions. Check if shutdown is due to UPS. ).