by Annie Waldman, ProPublica, with data analysis by Alma Trotter and Fred Trotter, CareSet

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More than 6.5 million Americans have peripheral artery disease, a condition in which arteries are obstructed, restricting blood flow, most often in the legs. The first sign is often leg pain during activity, also known as claudication. While most treatments are safe, in recent years, experts have warned that some doctors may be subjecting patients to invasive procedures too early in their disease progression, needlessly exposing them to risks of complications, including amputation and even death.

Over the past year, ProPublica has investigated these vascular treatments, and we found some doctors are earning millions of dollars conducting a questionable number of procedures. For treatments in outpatient clinics, federal insurers, like Medicare, pay generous reimbursements to doctors, who can charge tens of thousands of dollars for procedures done in a single office visit.

Treatments include widening the arteries with stents and balloons and clearing plaque from vessel walls with a laser or bladed catheter, also known as an atherectomy. Despite minimal evidence to support the treatment’s benefits compared with less expensive alternatives, atherectomies have surged in recent years, researchers have found, with hundreds of outlier doctors performing the procedure in a majority of their patient cases.

ProPublica found that, from 2017 through 2021, about 200 doctors accounted for more than half of atherectomy procedures and Medicare payments, totaling nearly $1.5 billion, according to public federal data. Many of these physicians work in outpatient clinics.

To better understand how doctors are using the procedure, ProPublica sought to analyze Medicare data for patients who underwent atherectomy treatments, working with the data journalism team at CareSet, a health analytics group that exists to transform Medicare data into insights for better patient care.

For our analysis, we set out to understand how often doctors were performing atherectomy procedures for patients in the early stages of disease. We relied on Medicare fee-for-service claims data and examined atherectomy procedures conducted over the past four years, from 2019 through 2022, limiting our analysis to the first-time atherectomy procedures that patients underwent during this time. We focused on initial atherectomy procedures to better understand whether interventions were occuring in the early stages of vascular disease, before possible progression of the illness. For each doctor, we calculated what percentage of their patients receiving a first-time atherectomy appeared to have had only more mild vascular disease, based on a diagnosis of claudication.

When a patient is treated by a physician, medical details on their diagnoses and procedures are submitted to insurers for reimbursement payments. The Centers for Medicare and Medicaid Services collect this data for patients covered by its federal insurance and share it with the public and researchers, removing names and other private information to protect patient privacy.

To examine doctor reimbursement for atherectomy procedures, ProPublica relied on Medicare’s provider use and payment dataset, which contains details on the services and procedures provided to Medicare beneficiaries by physicians and other health care professionals. This public data let us calculate how much Medicare paid each provider in reimbursement per type of procedure. We looked at five years of data, from 2017 through 2021, the most recent year available.

But the public reimbursement data does not include detailed information on provider behavior or patient diagnosis, so ProPublica partnered with CareSet, which has special access to Medicare claims data. The data included carrier, institutional inpatient and institutional outpatient claims. We used codes from the Current Procedural Terminology system, devised by the American Medical Association and used by Medicare, and we identified patients who underwent a first-time atherectomy procedure. We limited our analysis to patients who had procedures from Jan. 1, 2019, through Dec. 31, 2022.

We classified patients into two categories: those with more severe chronic disease, who had a diagnosis of chronic limb-threatening ischemia; and those who appeared to have milder vascular disease, based on a diagnosis of claudication. Patients with claudication were defined by the International Classification of Diseases code families I70.20, I70.21 and I73.9, a set of diagnosis codes used by other researchers in peer-reviewed studies. We omitted patients who underwent an atherectomy procedure before their first treatment in our study period. To do this, we looked back at the data 12 months before the start of our study period. We also excluded patients with a diagnosis of acute limb ischemia, which is often linked to an emergency event. We included patients who initially had a claudication diagnosis at the time of their first atherectomy procedure but whose disease may have advanced to a more severe stage during our study period, because of concerns that the interventions may have contributed to disease progression.

We pooled the patient-level data by doctor to calculate what percentage of each physician’s patients underwent a first-time atherectomy for claudication versus chronic limb-threatening ischemia.

We wanted to know whether doctors who conduct atherectomies are using the procedure excessively on patients who appear to have milder vascular disease.

For many patients with peripheral artery disease, an initial symptom is pain when walking or exercising, which is also known as intermittent claudication. The discomfort often arises from limited oxygen in the leg muscles due to the narrowing of arteries, which can progressively become obstructed with plaque. According to experts, the majority of patients who experience claudication will not develop severe vascular disease, like chronic limb-threatening ischemia. While endovascular interventions are recognized by experts as appropriate for severe disease, best practices recommend that milder symptoms initially be managed by noninvasive care, which can slow or........

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