It is almost impossible to kill Clematis by pruning. Clematis benefit from pruning and can be cut back at any time during active growing season. If nothing else happened to your Clematis, it it will definitely come back.

The combination of cold weather + rains + poor drainage can cause a crown rot which is fatal in most cases. If you will not see any growth, dig the rootball and examine it. Read the Gardengal's post about inspecting the roots in 'Clematis wilt' post.

Quoting Clematis author Linda Buetler:

"Clematis cannot read or count. They do not know in which pruning group they are"

"you cannot kill a clematis by pruning it"

thanks ... I will dig down and see what is happening. I thought I had good drainage, but maybe not. Oh, loved the 'clematis cannot read or count". Hahaha!