After Dr. Mark Midei was accused of implanting unnecessary heart stents in hundreds of patients at St. Joseph Medical Center in Towson, a Maryland Health Care Commission committee began developing safeguards to prevent a repeat situation.

But now, one of the committee's members — Dr. John Chung-Yee Wang, a former colleague of Midei's who heads the cardiac catheterization lab at Union Memorial Hospital in Baltimore — is himself accused of improper stenting in three separate legal claims.

The allegations could cast a shadow over the work of the advisory committee, which is expected to release its recommendations for legislative changes to improve oversight at a public meeting before the health commission Thursday. The case also highlights how stent-related allegations have expanded in Maryland from an initial inquiry into one doctor at one facility.

Inquiries have taken place at several hospitals, including Union Memorial and Washington Adventist in Takoma Park. Both facilities have been asked by state health officials to review policies and cardiology cases based on concerns about high stenting rates. And several physicians are being sued by patients in multiple states.

Stents are tiny mesh tubes that prop open blocked arteries and improve blood flow and have been recommended after someone's arteries are more than 50 percent or 70 percent blocked. Cardiology experts prefer that medical therapies and lifestyle changes be used for lesser blockages, noting that stents carry an increased risk of blood clots that could lead to death.

Stents have "definitely become a legal target," said Arthur Caplan, a medical ethicist at the University of Pennsylvania. He said that "blood is in the water" and lawyers are circling. He also raised concerns that the allegations against Wang could "create controversy" whether "true or not."

Medical malpractice attorney Jay Miller, who is litigating more than 200 cases against Midei, has filed two of three complaints against Wang.

One of the cases, filed in a state health claims arbitration office, alleges that Wang, Midei and another doctor — Kourosh Mastali — each wrongfully stented patient John Bowers in back-to-back years starting in 2005. All three cardiologists were at the time partners at MidAtlantic Cardiovascular Associates, a cardiology practice that has since disbanded.

A call to Wang's office Wednesday was transferred to the public relations team at Union Memorial, which has repeatedly declined to comment about the allegations. Mastali, whose Maryland medical license expired earlier this year, could not be reached.

Miller's second case, filed on behalf of patient Lorrie Skillman, claims that Wang overstated "the extent of the disease" in Skillman's artery to justify placing a stent.

The claims are similar to others found in lawsuits filed against cardiologists in Pennsylvania, Tennessee and Kentucky. The physicians frequently defend themselves by saying, as Midei has, that blockage estimation is an art that relies on multiple subjective factors — in addition to an X-ray image of an artery.

"The notion that we in the [cardiac catheterization] lab have a very precise method for mathematically determining the degree of obstruction is false. It's subjective," Midei said in an interview last week. He also praised Wang's work and lamented the possibility that another physician would fall prey to allegations of unnecessary procedures.

Many of Midei's patients stand by the procedures, saying they felt much better after the devices were inserted to improve blood flow. A total of 585 patients were told by St. Joseph that their stents might not be necessary.

But others worry about having a piece of metal they don't need implanted in their arteries, increasing the risk of blood clots and requiring that they take blood thinners.

The cases against Wang — though unproved — raise questions about the vetting process used by the Maryland Health Care Commission when accepting assignments to its technical advisory committee on stenting, said state Del. Peter A. Hammen, a Baltimore Democrat and chairman of the Health and Government Operations Committee.

A "background" review should have been part of the process, Hammen said.

Ben Steffen, acting executive director of the state's health care commission, declined to discuss the selection process, other than to say the group's 19 members were nominated by "key stakeholders and relevant state agencies." Wang was nominated to the group this summer by the Maryland Chapter of the American College of Cardiology.

By then, at least one woman, Martha Jane Phillips, had filed a complaint against him with the state's Board of Physicians, alleging in the filing last year that Wang placed unnecessary stents in her arteries. Phillips has since filed a lawsuit against Wang.

When asked by The Baltimore Sun about Phillips' claims in September of last year, Union Memorial spokeswoman Debra Schindler said in an emailed statement that "Dr. John Wang is an integral part of the quality healthcare that we deliver, and the rigorous quality assurance review process that we employ. … All of our procedures, including the stent procedure, are performed according to best practices within the cardiology profession."