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Peripheral arterial disease (PAD) interventions got moderate to poor ratings on evidence of effectiveness by a Medicare evidence development and coverage advisory committee (MEDCAC).

The panel's average scores largely hovered around 3 points on a 5-point scale for confidence in benefit in symptomatic lower-limb PAD.

"The lack of data is impressive and disappointing," said panel member , a cardiothoracic surgeon and director of the Mount Sinai Heart Institute Center for Medical Devices in New York City. "It's where cardiac valve disease was 30 years ago."

In an presented by , and , both of Duke University Medical Center, previously published in 2013 and updated qualitatively for the MEDCAC meeting, no intervention had evidence of benefit for asymptomatic patients and there was a high level of evidence for no benefit from aspirin in that group.

The panel members rated their level of confidence of a short-term benefit at 1 year for intervention for asymptomatic disease discovered through systematic screening at an average score of 1.4 on a 5-point scale, and that score only rose to a mean of 2.8 for long-term benefit at 5 years.

Those scores reflected a consistent theme voiced through the day-long discussion: that interventions for these patients can help their overall health but are unlikely to impact limb outcomes, noted the non-voting meeting chair, , director of the Center for Health Policy and Outcomes at Memorial Sloan-Kettering Cancer Center in New York City.

The panel member who voted the highest level of confidence in intervention for asymptomatic patients, , a radiologist at Vanderbilt University in Nashville, Tenn., agreed.

"Current guidelines for both primary and secondary prevention have significant benefit on cardiovascular hard [outcomes] and cardiovascular fatality anywhere from 20 to 40 percent," he said in explaining his vote. "That was the intervention I was thinking of -- lifestyle, control of risk factors, and medical intervention where appropriate."

"If we're saying ... this is a truly asymptomatic limb population, then there is nothing to do," said , director of the Vascular Medicine Program at the University of Minnesota Medical School in Minneapolis.

However, Hirsch, whose guest vote was not tallied in with those of the 10 voting panel members, suggested that PAD is never truly asymptomatic and likewise supported intervention for cardiovascular disease risk reduction.

For PAD patients with symptoms of intermittent claudication, the average votes of confidence in intervention were better, at 3.2 for short-term and 3.3 for long term benefit of treatment.

Swain and others argued that supervised exercise should be reimbursed for Medicare beneficiaries based on "very reasonable" results in the evidence review.

But on the issue of endovascular or open revascularization for these patients, the group was less certain, citing "moderate evidence" and questions on durability.

The evidence review turned up a large effect in intermittent claudication from supervised exercise training for improving walking distance but a low level of evidence for a moderate effect of aspirin and endovascular therapy alike.

Endovascular therapy had a high level of evidence for moderate effect on functional improvement but not quality of life. Survival and amputation-free survival appeared similar between open and endovascular procedures, although the review cautioned about limited evidence.

"I gave it a 3 and the reason I did was because it really is dependent on the level of disease," explained , chief of vascular surgery at the University of California Los Angeles, adding that "the durability is a major question with both open and endovascular approaches."

Swain agreed, saying she downgraded her vote because "we don't have good durability for endovascular or open surgical interventions, and I don't believe have good 5-year durability data for things like exercise."

, medical director of the Mercy Care Plan, voted 3 and 2 on the short- and long-term votes for intermittent claudication, respectively, "because the evidence report showed moderate level of confidence, moderate level of evidence and it didn't go past a couple years."

In critical limb ischemia, the panel again indicated "moderate" confidence, with scores averaging 3.6 for short-term benefit of treatment in the first 6 months and 3.0 for long-term benefit at 2 years.

While the studies again weren't robust, the standard of care in these cases is to do something rather than nothing, the panel members agreed in discussion after the vote.

"This is an issue where we could accept a lower level of evidence," said panelist , medical director of the BlueCross BlueShield Association's Center for Clinical Policy Technology Evaluation Center.

"If you have a patient population that truly has no other alternatives and is heading for limb loss, certainly this would improve outcomes," he noted. "But the reason why I only gave it a 3 and not higher is because I think that's a slippery slope for selecting patients. It's not easy to select just the patients who are going to lose their limb. You might end up selecting patients with less disease and potentially even do them harm."

The lukewarm recommendations for coverage nevertheless got praise from the Society of Cardiovascular Angiography and Interventions (SCAI).

"SCAI applauds the panel for supporting the physician's ability to make the best judgment for each individual patient's condition, and maintaining access to life-enhancing treatments," it said in a press release. "SCAI is pleased the panel sees the value of PAD interventions on patient outcomes, as evidenced by the panel's vote of intermediate confidence for nearly all levels of disease discussed today."

The Centers for Medicare and Medicaid doesn't have to follow the recommendations of its advisory panels. A CMS representative at the panel said the advice would be considered over the next 6 to 8 months for a possible coverage determination thereafter.

From the American Heart Association:

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