Mike McKee was walking up to 10 miles a day in 2008 when his heart abruptly stopped and he collapsed between his home and downtown Minneapolis office. Quick-reacting bystanders and paramedics got him to the hospital in time. A defibrillator and a heart stent got him back to walking but last year a clogged artery in his left leg began causing severe pain.

McKee, 65, had developed peripheral artery disease (PAD), one of the most common, debilitating and deadly conditions in the world.

McKee could have gotten a metal stent to reopen the artery, but he chose a supervised exercise program designed at the University of Minnesota that has proved as effective as angioplasty at less than half the cost. Researchers say it could alter the care for an estimated 2 million American PAD patients.

After just four weeks of supervised work on a treadmill, McKee says he’s back to walking ­several miles a day.

“I’m just confident next summer I’ll be doing 7 to 8 miles a day,” McKee said.

An article in the British medical journal the Lancet estimated that PAD affects more than 202 million people worldwide, including about 9 million in the U. S., where it leads to more than 150,000 amputations a year. In Minnesota alone, about 1,200 limbs are amputated annually as a result.

The disease is associated with advancing age, smoking, diabetes, high cholesterol, high blood ­pressure and heart artery blockages. Patients exhibit symptoms called “claudication,” described variously as discomfort, fatigue, cramping or pain in the leg muscles.

The U’s treadmill regimen differs from ordinary walking and requires trained supervision. The leg muscles are slowly stressed to moderate discomfort, followed by a few minutes of rest. Then the process starts over. Supervisors gradually increase the elevation of the treadmill over the course of three months or more.

The U researchers collaborated with Fairview Health System rehabilitation specialists on the program, which has spread to seven cardiac-rehabilitation clinics in the Twin Cities, making it the only place in the country where it’s so widely available.

The treadmill regimen joins a growing number of research projects that have shown that physical therapy can be as effective as surgery for some ailments, such as chronic pain in the shoulder, knee, neck or back. If widely adopted, it could slow a growing market for manufacturers of leg stents, like Twin Cities-based Medtronic.

Diane Treat-Jacobson, an associate professor at the U’s School of Nursing who ­specializes in exercise ­training in PAD patients, said it’s unclear how it works but one theory is that by gradually stressing the leg muscles to the point of oxygen depletion it changes the muscle metabolism to either extract more oxygen or become more efficient in how it’s used.

For now, stents remain the go-to treatment in about 9 out of 10 patients with claudication, said Dr. Alan Hirsch, a U cardiologist and vascular specialist who chairs a multi-center evaluation of the exercise program, which underwent a federally funded trial known by the acronym “CLEVER.”

The trial involved 119 patients who either received a stent, a six-month supervised exercise program, or standard medical therapy — a prescription drug that improves blood flow to the legs, and advice to exercise on their own. The supervised exercise got people walking significantly farther without pain than those who got stents or standard therapy alone, but the patients who underwent surgery were slightly more satisfied with their quality of life.

Critics said the trial was too small and some argued that the effects of stenting would outlast the effects of exercise. So researchers followed the patients 18 months after the trial completed and found the results essentially unchanged, Hirsch said.

Those results were presented last year at the annual meeting of the Society for Interventional Radiology by Dr. Timothy Murphy, medical director of the Rhode Island Hospital Vascular Disease Research Center. He also is lead author of a final article pending publication in the Journal of the American College of Cardiology.

A separate paper, published in November in the Journal of the American Heart Association, evaluated the cost-effectiveness and quality-of-life measures of supervised ­exercise vs. stenting. Lead author Dr. Matt Reynolds, director of economics and quality-of-life research at Harvard Clinical Research Institute, said the outcome was clear. “There’s no question in the medium term that the stenting approach is spending significantly more money per patient. And it is clear that in the medium term the global quality-of-life benefits [of stenting] are really not importantly better,” Reynolds said. “So my bias is, physicians should really be pushing this exercise thing a little bit more.”

One obstacle is insurance.

“There’s good reimbursement around the country for stenting; it’s not hard for patients and hospitals to get that paid for. There’s not nearly as good of coverage nationally for these exercise programs,” Reynolds said. “Medicare, for example, on a national basis does not globally cover this. And that doesn’t make any sense to us, really.”

Dr. David Cohen, director of cardiovascular research at St. Luke’s Mid America Heart Institute in Kansas City, Mo., senior author of the cost-effectiveness study, said he hopes it will make waves.

“Exercise delivers the vast majority of the benefit of stenting for a fraction of the cost,” Cohen said. “And therefore, if we were in a fully rational health care system, it would make sense that we should reimburse for the exercise as well.”

The researchers say they’re not against stents, which are needed by many patients. They simply argue that stents shouldn’t be the default.

Larry Lessard, 73, gets that. He had a heart transplant in 2004 and an aortic aneurysm a year later. It took two more years before his PAD symptoms were recognized. He then chose to have two stents put in his legs, but they didn’t alleviate his leg pain and resulted in an aneurysm. In 2013, he was finally referred to Hirsch and his exercise program.

Although he’s been a regular in aerobic-style exercise classes for years, it was the gradual, supervised increase of treadmill workload that made a difference. He said he could feel the benefit after just a few weeks.

“I was really surprised,” Lessard said. “It’s a tough road, but my goodness, you’ve got to do something,” he said. “If you’re going to just sit in the chair and not do anything about it, you’re not going to get anywhere.”