Lower extremity peripheral artery disease: the 2024 ACC/AHA guideline versus the 2016 guideline

This is the MedBulletins entry "What changed in the guidelines". Today we compare the 2024 American guideline on lower extremity peripheral artery disease with the previous one, from 2016. This is not news from this year: it is a comparison between two versions that are already published. The 2024 guideline states that it supersedes the recommendations of the 2016 guideline.

How to listen to this entry. For each topic we first say "Before", meaning what the 2016 guideline said; then "Now", meaning what the 2024 guideline says; and finally, the "Change". For every recommendation we keep two different things apart. The class tells you the strength of the recommendation. The level of evidence tells you the quality of the data behind it. A recommendation can be strong with limited evidence, or weak with good evidence. The 2016 guideline writes its classes in Roman numerals; here we read them as numbers.

About the levels of evidence, we name them by their letters: level A; level B, R, randomized; level B, N, R, nonrandomized; level C, L, D, limited data; and level C, E, O, consensus of expert opinion. The full definition of each level is in the official table of the American College of Cardiology and the American Heart Association. And one important point: a recommendation that is missing from 2016 does not mean it was contraindicated at the time.

Part one: antiplatelet therapy and anticoagulation.

Topic one. Single antiplatelet therapy in symptomatic peripheral artery disease. Before: aspirin alone, seventy-five to three hundred twenty-five milligrams a day, or clopidogrel alone, seventy-five milligrams a day; class one, level of evidence A. Now: single antiplatelet therapy is class one, level A. Clopidogrel alone, class one, level B, R. Aspirin alone, class one, level C, L, D. Change: modified. The recommendation is now split by drug, and the level of evidence for aspirin alone is lower than for clopidogrel.

Topic two. Antiplatelet therapy in asymptomatic disease. Before: with an ankle-brachial index of zero point nine zero or less, it is reasonable to reduce heart attack, stroke or vascular death; class two a, level C, E, O. Now: it is reasonable to reduce major adverse cardiovascular events; class two a, level C, E, O. Change: unchanged in class and level. Nuance: the ankle-brachial index threshold is no longer mentioned.

Topic three. Antiplatelet therapy with a borderline ankle-brachial index, between zero point nine one and zero point nine nine, without symptoms. Before: usefulness uncertain; class two b, level B, R. Now: there is no equivalent recommendation in that section. Change: no equivalent.

Topic four. Rivaroxaban two point five milligrams twice daily, plus low-dose aspirin, in symptomatic disease. Before: there was no recommendation. Now: effective to reduce major adverse cardiovascular events and major adverse limb events; class one, level of evidence A. Change: new.

Topic five. The same combination, low-dose rivaroxaban plus aspirin, after revascularization. Before: there was no recommendation. Now: recommended; class one, level A. Change: new.

Topic six. Dual antiplatelet therapy after revascularization. Before: aspirin plus clopidogrel may be reasonable for limb events; class two b, level C, L, D. Now: after endovascular revascularization, a P two Y twelve antagonist plus low-dose aspirin, for at least one to six months, is reasonable; class two a, level C, L, D. And after surgery with a prosthetic graft, for at least one month, it may be reasonable; class two b, level B, R. Change: modified. Note: class two b is a weak recommendation; its specific wording is kept for each recommendation.

Topic seven. Dual antiplatelet therapy without recent revascularization. Before: effectiveness not well established; class two b, level B, R. Now: benefit uncertain; class two b, level B, R. Change: unchanged in class and level. Nuance: the 2024 guideline restricts the population to patients without recent revascularization.

Topic eight. Oral anticoagulation to reduce events. Before: should not be used; class three, harm, level A. Now: full-intensity oral anticoagulation should not be used when there is no other indication, for example atrial fibrillation; class three, harm, level A. Change: modified. The class is the same; what is new is that it specifies full intensity and the absence of another indication.

Part two: diabetes.

Topic nine. Glucagon-like peptide one receptor agonists, such as liraglutide and semaglutide, and sodium glucose cotransporter two inhibitors, such as canagliflozin, dapagliflozin and empagliflozin, in peripheral artery disease with type two diabetes. Before: there was no recommendation. Now: effective to reduce major adverse cardiovascular events; class one, level A. Change: new. This recommendation applies only to type two diabetes and is not stated for limb outcomes.

Topic ten. Coordinating diabetes care within the team. Before: class one, level C, E, O. Now: class one, level C, E, O. Change: unchanged.

Topic eleven. Glycemic control and limb outcomes. Before: in critical limb ischemia, it can be beneficial; class two a, level B, N, R. Now: in peripheral artery disease with diabetes, of any type, it may be beneficial; class two b, level B, N, R. Change: modified. The class goes down, from two a to two b, and the population changes.

Part three: exercise.

Topic twelve. Supervised exercise. Before: in claudication, to improve functional status, quality of life and symptoms; class one, level A. Now: in chronic symptomatic disease, to improve walking performance, functional status and quality of life; class one, level A. Change: unchanged in class and level. Nuance: the population described and the outcomes listed change.

Topic thirteen. A structured community-based program with behavioral change techniques. Before: community or home based, can be beneficial; class two a, level A. Now: community based, effective; class one, level A. Change: modified. It moves up from class two a to class one.

Topic fourteen. Exercise as an initial option before revascularization. Before: supervised exercise should be discussed before possible revascularization; class one, level B, R. Now: supervised or structured community-based exercise should be offered as an initial option in functionally limiting claudication; class one, level B, R. Change: modified in wording; the class and the level do not change.

Topic fifteen. Supervised exercise after revascularization. Before: there was no specific recommendation, although the 2016 supportive text already backed supervised exercise alone or combined with revascularization, citing the ERASE trial. Now: in patients revascularized for chronic symptomatic peripheral artery disease, subsequent supervised exercise is effective; class one, level A. Change: new as a formal recommendation.

Topic sixteen. Alternative exercise modalities. Before: arm ergometry, cycling and pain-free or low-intensity walking could be beneficial; class two a, level A. Now: nonwalking structured exercise, for example arm ergometry, can be beneficial; class two a, level A. And walking that avoids moderate to severe ischemic symptoms has uncertain usefulness; class two b, level B, R. Change: modified. Remember: class two b is a weak recommendation; its specific wording is kept for each recommendation.

In summary: four new recommendations, seven modified, four unchanged, and one with no equivalent.

Now, our interpretation. This is no longer the text of the guideline. The most consequential practical change appears to be antithrombotic: low-dose rivaroxaban with aspirin becomes a class one option, at the cost of more major bleeding, according to the guideline itself. The guideline also notes that the benefit in the VOYAGER P A D trial was observed in patients without prior stroke or high bleeding risk. Moving community-based exercise up to class one may make it easier to prescribe where supervised programs are not available. And we do not read the lower class for glycemic control as a reason to loosen it.

Limitations. This entry covers only antithrombotic therapy, diabetes and exercise. It does not compare diagnosis, revascularization, critical limb ischemia, acute limb ischemia or follow-up. Classes and levels are cited exactly as each guideline publishes them; we have not re-rated any recommendation. Always check the original sources, linked on the page.