Pharmacy CVS has agreed to buy health insurer Aetna in a $69 billion deal. CVS’s CEO says he expects the deal to close next year.

And to get a sense of what this deal means, both for the companies involved, but also for patients, I called Toby Gordon. She's a professor of Health Care Management at Johns Hopkins University and is especially interested in innovations in health care delivery.

Gordon says this merger will be a big test of a market-driven innovation.