But before catheterization, patients and doctors should discuss the options, Hlatky said. When a doctor does the test and finds a significant blockage, most stents are placed immediately, during the same procedure. If a patient has reservations about having a stent put in, at that point, it's too late to discuss them, he said.
"You don't have a lot of time to reflect on this," he said. "The doctor sits there and says, 'I can do this now,' and they do. It's important to have the conversation beforehand."
But for some patients, these steps don't always unfold easily. Determining the severity of a blocked artery isn't an exact science, said Dr. Jon Resar, an interventional cardiologist and director of the adult cardiac catheterization laboratory at Johns Hopkins Hospital.
By clinical guidelines, an artery should be clogged at least 70 percent before a stent should be placed, Resar said. "A 50 percent blockage doesn't need to be stented," he said. "Give them Lipitor, control their blood pressure and have them exercise."But often, catheterization and a coronary angiogram, which takes pictures of the heart vessels, give a doctor a range of a blockage, not an exact number, he said. That wiggle room leaves the decision to use a stent in the hands of the cardiologist doing the procedure, making the device susceptible to overuse, he said.
"There are a lot of intermediate blockages that shouldn't be stented but end up being stented primarily because of financial incentive to the physicians who get paid for doing the procedure," Resar said.
Stents are big business for hospitals, which can charge $10,000 or more for the process.
Some insurance carriers are pushing for more stringent justification of stents, Resar said. Techniques that can help include using a pressure wire to help measure whether blockages are significant enough to warrant a stent, he said.
"Then you're not doing unnecessary procedures and not putting stents where they don't need to be," he said. "And you're decreasing costs by only treating blockages that need to be treated."
Still, whether to insert a stent can be a tough call for even the most ethical of clinicians, Aggarwal said.
"Nobody wants to miss heart disease," she said. "It's the No. 1 cause of death in men and women. There may be more aggressiveness on invasive testing because we want to make the right decision for the patient.
"It's not that bad cardiology is being practiced, it's not that we're not making good decisions," she added. "It's just not always clear."
Since a 2007 clinical trial found that drug therapy is often as effective as stents, cardiologists have been re-evaluating the use of the implants, Aggarwal said.
"That was a turning point for us," she said. "We stepped back and said, gosh, medical therapy is really great. Before, you see a blockage, you stent it. It works. It seemed so obvious. But it was a good opportunity for us to step back and say maybe we aren't giving enough consideration to medical therapy."
And even if a patient does end up getting a stent, that shouldn't be seen as the cure-all for a heart problem, Aggarwal said. Exercising, eating a healthful diet and quitting smoking are still crucial.
"Getting any procedure on your heart doesn't give you a free pass to not take care of yourself," she said.