Their existing properties are generally cash positive, and they're nearly done with Venetian-Macau and Palazzo using their existing ~$3B line of credit. None of that is really at risk.
What might cause them trouble is arranging the next ~$10B+ that they need to begin accessing right away to build stuff like Singapore that's already been given an opening date, but without the funding in place. If the lended crisis persists, and it slows down or prevents LVS from getting funds, it could at a minimum delay all those amazing expansion plans.
Long term, they're fine. If they wait long enough, the positive cash flow from the casinos they've already built can clear existing debt and/or pay for new development. And the lending crisis won't last forever - even if it lingers for a year or two LVS will still be here.
But they might not have a $200/sh stock price like the hypesters would believe is imminent...