I did a rough pruning a couple weeks ago, but am now waiting a few more days to go in and do a final cut as I wanted to make sure I knew exactly what was alive and undamaged. My reds (Foch, Oberlin Noir, and Marquette) were mostly fine with some death on the smaller diameter wood.
My Cayuga, unfortunately, appear to be another story. We had three consecutive -15F days and then another couple later on. Everything under about 3/8" in diameter is definitely dead. What was green when I cut it is now browning with no sign of bud break, although there was some water weeping a week after I cut it.
At this point I think the best I can hope for is that the 2 feet of snow on the ground protected the roots and I can bring up new trunks. Kind of depressing to put 6 years into the vines, get a couple good crops with close to 1gal/vine yield last year, and then lose them.