Charles E. Johnson Jr. was a hearty 62 in early 2008. He walked about 20 miles a month, worked out four times a week and played tennis on weekends.

But he noticed a tightness in his chest sometimes. So he went to St. Joseph Medical Center in Towson and saw Dr. Mark G. Midei, who found significant blockage in three major coronary arteries and used mesh stents to prop open two of them.

Johnson says he has been irreversibly disabled ever since. According to a lawsuit filed this year in Baltimore County Circuit Court, the stents caused a blood clot, which led to a heart attack and a series of medical events that left Johnson with permanent heart damage.

And now Johnson is questioning whether he should have gotten a stent in the first place.

"A lot of doctors would argue that he wasn't a candidate," said his attorney, Robert Weltchek.

Johnson's medical history illustrates what patients and researchers have found throughout the country since coronary stents became a multibillion-dollar medical industry: The devices might not be as safe — or as effective — as once thought.

But cardiologists are unclear about much more than simply whether stents have medical value, as evidenced by the case of Midei, who is accused of performing hundreds of unnecessary procedures yet is defended vociferously by patients and colleagues.

Some doctors still argue over seemingly fundamental details, such as how to measure blockage on an X-ray, or when it is appropriate to choose surgery over stenting or medication. And now they have a new uncertainty to resolve: Will placing a stent lead to a patient's survival or the doctor's indictment?

"Every interventional cardiologist is going to be afraid that some angry patient or angry attorney or disgruntled colleague or competitor is going to turn him in for doing unnecessary procedures," said Dr. William O'Neill, executive dean of clinical affairs at the University of Miami's Miller School of Medicine. He was hired by Midei's attorneys to review some of the Towson cardiologist's case files and says he found no unwarranted stents.

"Though we kind of brought it on ourselves," he added. "Two or four years ago, [the field of interventional cardiology] became overly aggressive."

Since the mid-1990s, stents have been hailed as a relatively risk-free alternative to coronary artery bypass graft surgery. But their use soared after the 2003 introduction of a drug-coated version that prevents scarring. The devices have brought in more than $1 billion to Maryland hospitals since mid-2004.

Recent scientific studies have cast doubt that stents are any more effective than surgery, however. And that, combined with the regulatory and legal climate created by Midei and a handful of other physicians across the county accused of similarly overusing stents, is contributing to a steady decline in the use of the devices.

The number of stent procedures in Maryland is expected to drop 25 percent this fiscal year to about 10,650, compared with a peak in 2006 of 14,255, according to data from the state Health Services Cost Review Commission.

"Everyone's taking a bit of a step back, and saying, 'Gee, should we really be doing all this?' and I think that answer is probably now no," said Dr. Thomas Aversano, an associate professor at the Johns Hopkins University's School of Medicine and its Heart and Vascular Institute.

The recent studies "gave some evidence that [stenting] really isn't any better to [some patients than] pills," Aversano said. "There is some downside to it, and there are risks."

O'Neill sees the slowdown as a correction from earlier days, when doctors were stenting patients specifically because they didn't see a "downside."

The tiny, tubular, mesh devices, which act as a sort of scaffolding to widen compromised arteries, are lucrative. They've improved thousands of lives by restoring healthy blood flow. And they're easy to insert, often placed during the same procedure that's used to determine whether a patient has blocked blood vessels in the first place, called a cardiac catheterization.

"For some of these doctors, it was like, 'I'm here, so let me go ahead and put a stent in,' " O'Neill said. "What we've learned in the last two years is that there is a price to pay, and you should be conservative."

Midei is accused of falsifying hundreds of medical records going back two years at St. Joseph to make it appear that patients needed stent procedures when they didn't. Investigators who have since reviewed the records say they show far less blockage than Midei wrote in his notes. He lost his privileges to practice at St. Joseph last year, and he has denied the accusations made against him.