But when a warranty card arrived in the mail for the device stitched into her heart, Vlahoulis got the first of several shocks.
Vlahoulis, of Niles, said McCarthy had told her he would choose a ring from those listed in a booklet he gave her. She flipped through it, but this ring wasn't there.
She checked the Food and Drug Administration's website, looking for the ring on the agency's list of approved devices. But she couldn't find it. When she contacted the FDA to ask about it, she received a startling email in reply.
"Due to our confidentiality concerns we are unable to provide any information about a product until after it is approved," the public affairs specialist wrote.
"Oh my God," Vlahoulis remembers thinking. "I can't believe this."
Patients in need of permanently implantable, life-sustaining medical devices may assume that the products have undergone rigorous clinical and regulatory scrutiny and that rules put in place to protect their rights are enforced to the letter of the law.
But that wasn't the case at Northwestern and other hospitals where two different annuloplasty rings co-invented by McCarthy were sewn into the hearts of more than 700 patients to treat their valve diseases over a number of years though the FDA didn't clear the rings until 2009.
The situation highlights the tangled web of interests patients face when they require medical devices not just at Northwestern but across the U.S., showing what can happen in a profitable industry with few controls and plenty of gray areas.
It's especially true when doctors study their own inventions using data from their patients, who don't always know of the potential conflicts of interest.
That's what happened at Northwestern, and it's a cautionary tale that centers on two questions: Were the rings experimental? And was McCarthy conducting clinical research on one of his inventions while receiving royalties or other payments from the manufacturer?
McCarthy is a world-class heart surgeon who has saved thousands of lives, improved the well-being of countless patients and made weighty contributions to the art and science of cardiac surgery. His recruitment to Northwestern from the Cleveland Clinic in 2004 was a coup, instantly making the hospital one of the nation's premier cardiac centers.
In an interview, he said the rings' manufacturer had told him they were cleared for use under FDA rules. The hospital received those same assurances, a spokeswoman said.
In fact, the company — California-based Edwards Lifesciences — had not submitted the rings to the agency for review. It would later argue, incorrectly, that doing so was not necessary under FDA regulations.
McCarthy, who does about 150 valve surgeries a year, said that at the time he had no knowledge of the rules governing medical devices and that he relies on industry and the FDA to ensure the ones he uses are safe and effective.
"There are no guideposts for us," he said. "You don't learn about this stuff in med school."
He also said he had stopped telling patients some of the heart rings he uses were his inventions because most didn't seem interested in such details.
The controversy over the device Vlahoulis received triggered an FDA investigation that found Edwards should have sought FDA clearance before allowing surgeons to use two of its annuloplasty rings. But the agency took no action against the company, saying it had "made a good faith effort" to follow the law, and soon allowed the devices back on the market.