CLIPPER Attempts to Draw Out Useful Quality Metrics for CLTI

PHOENIX, AZ—Troubling disparities in care and outcomes for the most vulnerable patients with chronic limb threatening ischemia (CLTI) signal the need for quality measures to keep hospitals in check, according to results of a large Medicare analysis presented here at the Society for Cardiovascular Angiography and Interventions (SCAI) 2023 Scientific Sessions.

Researchers are hoping to pinpoint why so many CLTI patients seem to receive minimal vascular care and what’s driving the epidemic of unnecessary amputations. To do so, they created the CLIPPER cohort.

“Unlike other common and morbid cardiovascular diseases like heart attack, stroke, [and] heart failure, there are no quality metrics to measure process of care in CLTI,” said Alexander Fanaroff, MD (Perelman School of Medicine at the University of Pennsylvania, Philadelphia), during his presentation. CLIPPER was derived from the baseline characteristics and long-term outcomes of 1.13 million Medicare patients (mean age 75 years; 48.4% women, 14.6% Black) managed in inpatient and outpatient settings. Half had diabetes, 80% had hypertension, and one-quarter had kidney disease.

Approximately 70% of patients had ankle-brachial index testing within the 6 months before or after entry into the study, 54% had duplex ultrasonography, and 33% underwent angiography. Slightly less than half of all patients had more than one imaging test.

Within 30 days of a CLTI diagnosis, about 20% of patients underwent endovascular or surgical revascularization, which was more prevalent in those with Rutherford classes 5 and 6. By 6 months after diagnosis, 3.3% had undergone major amputation. Mortality rates were 16.7% at 1 year, 50% at 5 years, and 76.5% at 10 years.

The findings were simultaneously published in JSCAI.

What Do We Measure?

Fanaroff noted that process and outcome measures captured from administrative claims data and registries have been successfully used as quality indicators in heart failure, MI, and stroke. Drawing an analogy to door-to-balloon and door-to-needle times, which have become benchmarks for quality in STEMI care, he said it may be possible to zero in on a similar metric or metrics for CLTI that could be used to evaluate care at individual hospitals and health systems.

“The next steps will be looking at association between various process measures and outcomes to discover things like time from diagnosis to revascularization, the extent to which patients receive subspecialty care, wound care, imaging, and revascularization,” he noted.

Unlike other common and morbid cardiovascular diseases like heart attack, stroke, [and] heart failure, there are no quality metrics to measure process of care in CLTI. Alexander Fanaroff

In a press conference prior to Fanaroff’s presentation, he said the CLIPPER data set is a good first step toward identifying problems and will allow for future deep dives by sex, race, socioeconomics, and geographic location “to understand where quality of care is lagging [and what can be done] to improve it.”

In patient groups that are having good outcomes, he added, the data may reflect earlier revascularization strategies, better wound care, or more frequent doctor visits. “If so, then you can say: ‘If that's why these patients have better outcomes, then we should be doing this for all patients,’” Fanaroff added.

“The other final point is we've probably got to link up with primary care physicians,” said David A. Cox, MD (Sanger Heart & Vascular Institute, Charlotte, NC), who moderated the press conference. “This is a great opportunity [to] come up with ideas and thoughts and plans with the people that are taking care of these patients.”

A Failure of the Entire Healthcare System

Earlier in the day, Fanaroff presented additional research using Medicare beneficiary data to analyze CLTI patients who underwent amputation, which found that only 55% had seen a vascular specialist before that amputation and just 39% had undergone revascularization. By race, Black patients were less likely than white patients to have a primary care physician or vascular specialist visit in the year prior to a major lower-extremity amputation, or to receive surgical or endovascular revascularization.

The findings regarding what happened ahead of amputation were consistent even in metropolitan areas with ready access to specialty PAD care.

“What these data highlight is the difficulties in untangling race and socioeconomic status in our highly geographically segregated US cities,” Fanaroff said. He added that there are numerous junctions at which patients can get lost in the complicated pathway that they must negotiate to get from the development of PAD to appropriate care, dodging amputation along the way.

“An amputation is not a failure at the moment when a patient presents with critical limb ischemia—it’s a failure of the entire healthcare system and represents a missed opportunity to intervene in a disease that progresses over years and years,” he said. “We need to think about how we can improve referral patterns to vascular subspecialists and improve patients’ access to vascular care and testing. And in the best case, change incentives to reward health systems for avoiding amputations in their catchment areas, especially among our most vulnerable patients.”