They Lost Their Legs. Doctors and Health Care Giants Profited.

Troy Kirkpatrick, a spokesman for Becton, Dickinson & Company, which bought Bard in 2017, said collaboration between device companies and doctors is valuable. He described Dr. Mustapha as a leading expert on peripheral artery disease, whose work “aligns with our own ‘Love Your Limbs’ initiative in preventing amputations and improving patients’ lives.”

Dr. Mustapha made the most money — $633,200 — from Cardiovascular Systems International, known as C.S.I. Dr. Saab also received hundreds of thousands of dollars.

Dr. Mustapha said the payments were for teaching and consulting “so that I can spread the word and raise awareness” about treatment for peripheral artery disease.

Dr. Saab said, “All the medical decisions I make are motivated solely by what’s in the best interest of my patients.”

C.S.I. has a history of paying doctors to get them to use the company’s atherectomy devices. In 2016, the company agreed to pay $8 million to settle federal allegations that it had given illegal kickbacks.

According to a former C.S.I. executive, the company also contributed $100,000 to the CLI Global Society. The group was co-founded by Dr. Mustapha to advance the “common business interest” of doctors focused on severe artery disease. The society publishes a journal that frequently runs industry-sponsored studies that support the regular use of atherectomies and other procedures.

Dr. Barry Katzen, the president of the society, said the group was financed by its members as well as grants from companies.

A spokesman for Abbott, which bought C.S.I. this year, declined to comment on the company.

This year, Dr. Saab registered a business in Traverse City, Mich., using the same name as his and Dr. Mustapha’s other clinics. It is in a building with a podiatry clinic, whose website says it screens for peripheral artery disease. In May, Dr. Saab’s new business received a loan from Philips Medical Capital.

Susan Beachy contributed research.