Vascular specialist response to Medicare Evidence Development Coverage Advisory Committee (MEDCAC) panel on peripheral artery disease of the lower extremities

Abstract

Endorsed by the American College of Radiology (ACR), The Society for Cardiac Angiography and Interventions (SCAI), Society of Interventional Radiology (SIR), Society for Vascular Medicine (SVM), and Vascular InterVentional Advances (VIVA)

Introduction

On July 22, 2015 in Baltimore, Maryland, the Centers for Medicare and Medicaid Services (CMS) convened a Medicare Evidence Development and Coverage Advisory Committee (MEDCAC) panel to focus on lower extremity peripheral artery disease (PAD). The goal was to examine the scientific evidence of currently employed interventions that aim to improve health outcomes in the Medicare population, and address areas where evidence gaps may exist (https://www.cms.gov). The recommendations from this committee will then be considered by CMS as the basis for any future determinations about Medicare coverage for any interventions related to PAD. Therefore, the impact of this committee’s advice to CMS may affect millions of Americans over the age of 65 years with PAD.¹

The MEDCAC committee considered the impact of three categorical non-mutually exclusive interventions, namely medical therapy, exercise training, and revascularization (endovascular or surgical) on asymptomatic patients with PAD; patients with intermittent claudication; or those with critical limb ischemia. The intermediate/near-term and long-term outcomes of interest were reduction in pain; avoidance of amputation; improvement in quality of life and/or functional capacity including walking distance; wound healing; avoidance of cardiovascular events (including myocardial infarction, stroke, cardiovascular death) and all-cause mortality; and avoidance of harm from the specific interventions. Furthermore, for each condition, panel members rated (on a scale of 1 to 5) the degree of confidence they had that a particular intervention impacted the outcome/s of interest. The results were averaged. Therefore, a total of six averaged scores were provided.

Given the potential impact of MEDCAC panel recommendations on the health of patients over the age of 65 who suffer from PAD, a coalition of seven not-for-profit organizations – including the American College of Radiology (ACR), American College of Cardiology (ACC), American Heart Association (AHA), The Society for Cardiac Angiography and Interventions (SCAI), Society of Interventional Radiology (SIR), Society for Vascular Medicine (SVM), and Vascular InterVentional Advances (VIVA) – was formed. Collaboratively, the coalition represented more than 150,000 members who routinely manage patients with PAD. This cooperative effort was unprecedented, and reflects the commitment of the member organizations to their patients who suffer from PAD.

Here we summarize the comments and responses to panel questions made by members of this Coalition during the MEDCAC panel meeting (Table 1).

Table 1.

Recommendations of the Coalition to MEDCAC questions according to condition, categorical interventions, and immediate or long-term outcomes.*

Conditions	Categorical Intervention	Recommendation
		Immediate/near-term	Long-term
Asymptomatic
	Medical Therapy	Intermediate	High Confidence
	Exercise Training†	Intermediate	Intermediate
	Intervention	Low Confidence	Low Confidence
Intermittent Claudication
	Medical Therapy	High Confidence	High Confidence
	Exercise Training	High Confidence	Intermediate
	Intervention‡	High Confidence	Intermediate
Critical Limb Ischemia
	Medical Therapy	High Confidence	High Confidence
	Exercise Training	Intermediate	Intermediate
	Intervention	High Confidence	High Confidence

Scored according to the recommendation by CMS and MEDCAC as low confidence, intermediate, or high confidence.

†

Any form of exercise therapy to prevent cardiovascular outcomes.

‡

Only after failed attempt at medical therapy, lifestyle modification and supervised exercise training and in conjunction with those.

Asymptomatic PAD

The association between PAD and cardiovascular morbidity and mortality is well known; however, the majority of patients with PAD remain unrecognized or undiagnosed.¹ Importantly, most of these patients are over the age of 65 years.^{2, 3} Indeed, history and physical examination have significant limitations in identifying those individuals with PAD, as the majority have atypical symptoms or are considered asymptomatic.⁴ This has significant public health implications since PAD is considered a coronary artery disease risk equivalent, and, if unrecognized, carries significant morbidity and mortality.⁵ Even those patients with asymptomatic PAD tend to have shorter 6-minute walk test results and poorer functional status.⁶ Furthermore, timely diagnosis of PAD may lead to aggressive risk factor intervention as recommended by the AHA/ACC guidelines, and potentially result in a lower incidence of adverse cardiovascular and limb events. Data from the National Health and Nutrition Survey suggests that most patients remain undiscovered, are not treated with standard risk reduction medications, and the absence of appropriate medical therapy increases mortality significantly.⁷

Once PAD has been identified, appropriate attention to anti-platelet therapy, lipid lowering, blood pressure control, smoking cessation, exercise, and diet modification should be given (ACC/AHA guidelines).⁵ Indeed, the Coalition noted that the ankle brachial index (ABI), the test used to identify PAD, should be reclassified by CMS, based on CMS criteria, as a diagnostic test to permit patient identification and treatment. In contrast, the Coalition found no benefit for routine supervised exercise training or any form of revascularization in patients with asymptomatic PAD.

Intermittent claudication

Intermittent claudication, the symptomatic form of PAD, is associated with reductions in in longevity and functional capacity. A number of medical therapies, including lifestyle modification, cigarette cessation, statin therapy, anti-platelet therapy, and blood pressure control, have been shown to reduce cardiovascular morbidity and mortality in patients with PAD; these have been endorsed by all current guidelines.⁵ Of note, Cilostazol is the only medication that has been systematically shown to improve walking distance in patients with intermittent claudication.⁵ Unfortunately, despite these recommendations, many patients with PAD are undertreated.⁸ The Coalition strongly believes that comprehensive medical intervention as described by the current guidelines has both immediate/near-term and long-term benefits in patients with intermittent claudication.

Supervised exercise training has been shown to result in significant improvement in maximum walking time, pain-free walking, and maximum walking distance; however, despite the preponderance of data, this therapy is currently not reimbursed by CMS.⁹ While unsupervised exercise has some advantages, a meta-analysis of 27 studies demonstrated that supervised exercise is effective at improving maximum walking and initial claudication distance whereas unsupervised exercise therapy alone provides little or no benefit.¹⁰ The benefit for supervised exercise therapy has been reported by the Agency for Healthcare Research and Quality (AHRQ) in its ‘Treatment Strategies for Patients With Peripheral Artery Disease.’¹¹ Therefore, the Coalition strongly recommends full coverage of supervised exercise training programs for Medicare patients with intermittent claudication.

The Coalition also discussed the role of endovascular and open surgical therapies for patients with intermittent claudication. Recent data from the CLEVER and IRONIC trials demonstrate that endovascular intervention is complimentary to optimal medical therapy, and is associated with significant improvement in walking distance, quality of life as measured by the walking impairment questionnaire (WIQ), peripheral artery questionnaire, and physical limitation and quality of life scales.¹² The recent AHRQ review found that endovascular intervention, when added to exercise, improves both maximum walking distance and initial claudication distance more than endovascular intervention or exercise alone.^11–14

A number of trials, including those of drug-eluting stents, drug-coated balloons, and registries, were discussed. Studies using randomized and non-randomized prospective registry data have recently been published with 1-year patency rates of > 80% and target lesion revascularization (TLR) rates < 10%.^15,16 Collectively, newer technologies have resulted in an improvement in outcomes and quality of life; however, there remains a knowledge gap regarding cost effectiveness and objective improvement in physical functioning. In addition, the literature comparing outcomes of one endovascular intervention to another is lacking. Finally, there remains a knowledge gap for the relative effectiveness (but not relative safety) of surgical versus endovascular revascularization for patients with intermittent claudication.

Overall, the coalition felt that there was sufficient evidence for medical therapy, supervise exercise training, and revascularization in appropriate patients with intermittent claudication. The Coalition recognized the reported trend or increased use of endovascular procedures within the United States, but noted that arterial interventions were stable over 8 years whereas there was a significant increase in endovenous ablation procedures.¹⁷ Future analyses must separate endovenous procedures from intra-arterial revascularization. While all patients with intermittent claudication should be considered for aggressive medical and supervised exercise training, revascularization should be limited to individuals with significant lifestyle-limiting claudication who have failed medical and exercise training, as recommended by the current ACC/AHA guidelines.⁵

Critical limb ischemia

Critical limb ischemia (CLI) is classically defined as ischemic pain in the foot, ankle, or leg at rest, with or without ischemic ulcerations or necrotic tissue (generally defined as Rutherford class 4–6). The main consequences of this condition, in addition to increased death, stroke, and myocardial infarction rates, are amputation, disability, pain, depression, anxiety, decreased mobility, and declining physical fitness. Management of CLI is associated with substantial healthcare and societal costs, and these are expected to grow given the aging of the Medicare population and the expanding prevalence of diabetes mellitus and chronic kidney disease.^18–20

The goals of therapy in patients with CLI are two-fold: 1) prevention of cardiovascular and cerebrovascular events (death, stroke, and MI) and 2) relief of pain, timely healing, and prevention of amputation and its physical and psychosocial consequences.

Published guidelines have recommended lipid-lowering medications, anti-platelet therapy, antihypertensive medications, and smoking cessation for all patients with CLI for prevention of cardiovascular endpoints. However, there are no randomized clinical trials in patients with CLI that have shown a decrease in revascularization rate, an increase in patency, a lower amputation rate, or faster wound healing with medical therapy alone.²¹ A number of observational and single center studies have shown that patients with PAD and CLI are under-treated with guideline-recommended therapies (anti-platelet therapy, statins, and antihypertensive therapies).²² Furthermore, under-treatment with guideline-recommended therapies was associated with increased repeat revascularization and amputation in patients undergoing revascularization.²³

The role of supervised exercise training is limited in patients with CLI, given the extent of disease, associated ulcers or gangrene, and the fact that arterial perfusion is inadequate for basal metabolic requirements and not sufficient to improve the metabolic efficiency of exercising muscles. Indeed, exercise therapy does not address the specific treatment goals of CLI.

The cornerstone of therapy for CLI is improvement in perfusion through revascularization. Revascularization for CLI is recommended as Class I by all professional societies and guidelines.^{5, 24} In the absence of successful revascularization, up to 40% of patients will require limb amputation, which is associated with an annual mortality rate that exceeds 20%.²⁵ Patients with critical limb ischemia have two revascularization options available to them: 1) surgical and 2) endovascular. A hybrid approach that combines surgery and endovascular has also been described. To date, one randomized trial, ‘Bypass versus Angioplasty in Severe Ischemia of the Leg (BASIL)’, has examined surgery versus endovascular therapy among 452 patients with CLI.²⁶ After five years of follow-up, both surgery and endovascular intervention had similar rates of amputation-free survival and mortality. The recent review by AHRQ found no differences in all-cause mortality, amputation, and amputation free survival among the two therapies.¹¹

In the BASIL trial, surgery was found to be more expensive and was associated with a higher incidence of wound infection and longer hospital stay. The most important finding from BASIL and other non-randomized observational studies is that the choice of revascularization should be individualized. Some believe that surgery may be the best option for those with long segment arterial occlusions, good distal targets, available venous conduits, acceptable co-morbidities, and anticipated longevity. Alternatively, the endovascular approach is less invasive and does not require a bypass conduit. In the last decade, multiple publications have shown an increasing rate of endovascular procedures while rates of open surgery and amputations have declined.²⁷ The NIH-supported BEST-CLI trial (‘Best Endovascular versus Surgical Therapy’) promises to provide valuable evidence regarding which patients will benefit from surgical versus endovascular intervention. The Coalition encourages enrollment in BEST-CLI, which will add significantly to our evidence base in CLI.

A significant proportion of patients with CLI have complex vascular anatomy with long segment arterial occlusions.²⁸ Over 90% of patients with CLI have some degree of occlusion in the superficial femoral artery (SFA) or, importantly, in the tibial arteries. Because of this vascular complexity and poor surgical options (and/or high surgical risk) in many cases, endovascular treatment is the only available option. Endovascular revascularization in these cases is time consuming, often requires a large number of devices, and may benefit from a multidisciplinary approach for optimal outcomes. Yet, the current CMS payment system treats all endovascular procedures similarly, regardless of indication or complexity. There is concern that, in the current health care reimbursement climate, physicians and hospitals may be discouraged from treating complex disease in patients with CLI. Given that such patients may stand to benefit the most from revascularization by preventing the need for amputation, coverage and reimbursement should be aligned to encourage appropriate revascularization of CLI patients.

The Coalition strongly believes that medical therapy and revascularization have immediate/near-term and long-term impact on all outcomes related to individuals with CLI. However, the optimal and best revascularization strategy should be personalized to each patient.^29,30

Gaps

The Coalition remains concerned about significant disparities in amputations and revascularization rates by race, socioeconomic status (SES), and geography.³¹ Overall, black patients are twice as likely to undergo amputation compared to non-black patients. This rate is even higher among patients over the age of 75 years.³² Furthermore, the likelihood of revascularization is significantly lower among those residing in lower SES neighborhoods. Quality metrics that are tied to CMS payments should hold all parties accountable for the highest quality care given to all patients regardless of race and SES.

There is also concern about significant geographic disparities in amputation rates in the United States despite many advances in techniques and technologies.³³ Some of this variation may be related to concomitant co-morbidities; however, the Coalition remains concerned about access to qualified physicians with significant experience managing CLI. Therefore, it is important to train radiologists, cardiologists, vascular surgeons, and vascular medicine specialists so that they can effectively diagnose and treat PAD. The Coalition endorses the concept of CLI teams, which may include endovascular and surgical specialists, podiatrists, orthotists, and other wound care specialists for optimal care ( Table 1 ).

Finally, it should be noted that peripheral artery disease is not a disease, per se; it is a clinical manifestation of systemic atherosclerosis, similar to coronary heart disease and cerebrovascular disease. However, patients with PAD do not receive the same access to care or have the same outcomes as do patients with the other clinical manifestations of atherosclerosis. There is limited access to diagnostic testing, no access to exercise rehabilitation, poorer case findings, inadequate provision of medical therapy, and heightened rates of limb-specific morbidity. Patients with systemic atherosclerosis manifesting with lower extremity signs and symptoms deserve the same level of care as their brethren with CAD and stroke.

Conclusions

There is a worldwide pandemic of PAD, with the aging of the population and increasing incidence of risk factors such as diabetes mellitus and obesity. We commend CMS for taking the initiative to examine the current evidence and gaps related to PAD diagnosis and treatment. Peripheral artery disease is an entity associated with significant morbidity and mortality, and requires a timely diagnosis. Proven therapies, such as supervised exercise therapy, should be offered to all Medicare patients with intermittent claudication. Revascularization is appropriate for patients who have intermittent claudication that is lifestyle-limiting despite non-invasive measures. Revascularization for patients with CLI should be encouraged and reimbursed according to quality of care and outcomes. Systematic collection of reliable data regarding management of all patients with PAD will enhance our understanding of outcomes and help define appropriate care for the future. Disparities in amputation, revascularization, and access to medical care should be recognized and eliminated.

Footnotes

This article is being co-published in the following journals: Vascular Medicine; Journal of the American College of Radiology; and Catheterization and Cardiovascular Interventions.

Author disclosures

Mehdi H. Shishehbor: Non-compensated advisor and educator without any personal compensation from Medtronic, Boston Scientific, Abbott Vascular, Spectranetics, Cardiovascular System Inc, Cook Medical, Merck, and Terumo. Research grant from National Institute of Health and Astra Zeneca.

Herbert Aronow: None to report.

John R. Bartholomew: None to report.

Joshua A. Beckman: Consultant to Merck, Novartis, Astra Zeneca, Bristol Myers Squibb; VIVA Physicians, a 501 c 3 not-for-profit education and research organization.

James B. Froehlich: Consultant: Pfizer; Merck; Boehringer Ingelheim; Janssen pharmaceuticals; Johnson & Johnson; Novartis. Grant support: Jansson pharmaceuticals; Pfizer; Blue Cross Blue Shield of Michigan; Fibromuscular Disease Society of America.

Robert Lookstein: Consultant: Boston Scientific, Bayer Healthcare, The Medicines Company,Research Support: Venite, Boston Scientific, Spectranetics, Philips Healthcare Clinical Events Committee: Shockwave.

Sanjay Misra: Consultant: Boston Scientific; DSMB Chair Flexstent Cordis J and J, Research Grants: National Institute of Health, Boehringer Ingelheim.

Anne Roberts: None to report.

Kenneth Rosenfield: Consultant/Scientific Advisory Board: Abbott Vascular, Cardinal Health, Inari Medical, InspireMD, Surmodics, Volcano/Philips.Consultant/Scientific Advisory Board with Equity or Stock Options: Capture Vascular, Contego, CRUZAR Systems, Endospan, Eximo, MD Insider, Micell, Shockwave, Silk Road Medical, Valcare; Personal Equity: CardioMEMs, Contego, CRUZAR Systems, Embolitech, Icon, Janacare, MD Insider, Primacea, PQ Bypass. Research or Fellowship Support: Abbott Vascular, Atrium, NIH, Lutonix-Bard; Board Member: VIVA Physicians.

Michael R. Jaff: Non-Compensated Advisor: Abbott Vascular; Boston Scientific; Cordis; Medtronic; Paid Consultant: Cardinal Health; Equity Shareholder: PQ Bypass, Primacea; Board Member: VIVA Physicians, a 501 c 3 not-for-profit education and research organization; The Society for Cardiac Angiography and Interventions.

Provenance and peer review

Not commissioned; reviewed internally and by endorsing societies.

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