No, no risk of dying as nothing happened to the root system. The lack of stems does mean that there will be no bloomage in early Spring from the flower buds that macrophyllas normally develop in late summer or early Fall. Being in Chicago though, you would probably not get that early Spring bloomage unless you winter protected. Late blooms would not be affected.
Next year, all new growth will consist of new stems from the crown in Spring. If these stems get tall and old enough, they will produce flower buds and blooms around late summer... or thereabouts.
As far as care, I would make sure they have 2-4" of mulch. Keep the soil moist. .. as usual. do not fertilize. Water deeply if temps are scheduled to go down well below freezing and the soil has not frozen yet. The only bad thing about pruning late is that it can make some plants go into "grow" mode just as frosts and freezes arrive.
Luis
