likely that it is just sleeping....be patient....If you absolutely MUST know then gently scratch a LITTLE of the coating off the stem low down. If its green underneath its alive...if its brown then that stem is probably dead but the can shoot from the base so wait and see!
Agree with the others. I prune mine back quite severely in the autumn and have often thought I'd killed it off. Come the spring, come the growth then the flowers.
Some decades ago I recall planting a clematis. If memory serves it seemed alive at the time. A while later I realised I'd not seen it. Never found it again. Are they capable of surviving planting ?