KEY PERSPECTIVES
This article summarizes contemporary key items necessary to understand when developing and implementing a supervised exercise therapy (SET) program for those with symptomatic peripheral artery disease.
Clinical exercise program staff should familiarize themselves with all aspects of SET, which include patient recruitment and selection, SET implementation and progression, and insurance and billing information.
It is well established by numerous randomized controlled trials that regular structured exercise therapy improves the walking performance of those with symptomatic peripheral artery disease (PAD).1 2 , 3 4 5
Currently, little is known about the implementation of SET in the United States. Dua et al6
AEROBIC EXERCISE MODES AND PRESCRIPTION FOR SET
Peripheral artery disease is caused by atherosclerotic lesions and obstructions in the arteries of the lower extremities, which reduces blood flow to the leg musculature and causes a mismatch between oxygen supply and metabolic demands of the muscle during exercise.7 8 9 , 10 11 12 13 14 15 16 11 17 18
The goal of SET for patients with PAD is to improve walking performance. Most studies have demonstrated the efficacy of intermittent treadmill walking exercise in patients with PAD.19 Figure 1 . Table 1 provides the pain/discomfort scale. This training pattern should be continued throughout the 12 wk/36 sessions of a SET program.
Figure 1.: Progressive treadmill walking training program example for supervised exercise therapy (SET) in those with symptomatic peripheral artery disease. Each arrow provides information about decisions to be made for individual patient participating in SET. This figure is available in color online (
www.jcrpjournal.com ).
Table 1 -
Pain/Discomfort Scale for Exercise Training
a
0: No pain
1: Initial pain/discomfort, very mild
2: Mild pain/discomfort
3: Moderate pain/discomfort
4: Severe pain/discomfort
a Careful use of the pain/discomfort scale is important. All patients should be anchored to what “no pain” and “severe pain” feel like. This will improve the likelihood that a patient can recognize when he or she is at the “mild” or “moderate” pain/discomfort levels. Some guidelines refer to level 3 as moderately severe pain/discomfort.
Although the typical mode of exercise during the SET program is treadmill exercise, alternative modes of exercise may be utilized.4 , 8 20–22 23
It is recommended that the initial exercise prescription begin with intermittent treadmill walking and then switch to another mode if needed for safety, or if the patient does not progress after performing several sessions of treadmill exercise. Examples are provided in case format later in this article. If patients who perform these alternative modes of exercise experience ischemic leg symptoms (ie, pain/discomfort of claudication), progression would mirror that of treadmill exercise. If no pain/discomfort is experienced, progression of the exercise prescription would be based on rating of perceived exertion and target heart rate.10
For the first SET session, the exercise professional should have specific objectives as described previously.10 Table 2 . Also refer to Figure 1 and Table 1 for information on progression and the pain/discomfort scale.
Table 2 -
Exercise Prescription for Training Patients With Peripheral Artery Disease With Claudication
a
Variable
Recommendation
Ideal modality
Supervised treadmill walking
Intensity
40-60% maximal workload based on baseline treadmill test
Session duration
Begin with 30-50 min intermittent exercise with the goal of accumulating 30-50 min of total walking exercise
Maximum claudication intensity
Mild to moderate pain/discomfort (see )
Work-to-rest ratio
Ideally walking duration should be between 5-10 min. If mild/moderate pain/discomfort occurs earlier than 5 min, then intensity should be reduced. If later than 10 min, then intensity should be increased. Walking bouts are followed by rest until pain/discomfort has dissipated (often in 2-5 min)
Frequency
3 times/wk supervised; supplemented with home walking
Program duration
≥12 wk and 36 sessions; consider more sessions as indicated by individual patient
Progression
Every 1-2 wk or greater: increase duration of training session to achieve 50 min (see Figure 1 )
Maintenance
Lifelong maintenance ≥2 times/wk, but preferably 6-7 times/wk
a Adapted from Treat-Jacobson et al.
10
EXERCISE TRAINING LOCATION: CLINIC VERSUS COMMUNITY SETTINGS
RATIONALE FOR CONSIDERING COMBINING SET AND HOME-BASED EXERCISE SESSIONS
During the initial SET program, a total of 36 exercise sessions are covered during a 12-wk period by CMS and most commercial insurers.10
In addition, although a SET program is highly efficacious to improve walking ability, overall functional status, and health-related quality of life,9 24–26
PRACTICAL ASPECTS FOR COMBINING SET AND HOME-BASED EXERCISE SESSIONS
During the initial 12-wk program, three SET sessions and more should be performed each week, with a goal of two additional home-based exercise sessions and more included in the weekly exercise prescription to provide an adequate volume of weekly exercise. Given that these exercise sessions will be performed at a moderate intensity or above, the combination of the SET and home-based sessions will enable patients to meet the 2018 aerobic Physical Activity Guidelines for Americans by performing 150-300 min/wk of moderate-intensity aerobic activity.27
In addition, another advantage of combining SET sessions with home-based exercise is that patients learn to incorporate exercise into their lifestyle. This aspect becomes increasingly important if patients transition from the 12-wk/36 visit program to an additional 36 SET sessions afterward. As an example, one approach to this phase might be completing one SET session/wk for 36 wk, supplemented with four home-based exercise sessions/wk. The SET sessions could be interspersed >1 wk apart to lengthen the total time of utilizing all the additional 36 SET sessions, if desired. In this manner, a similar weekly volume of exercise can be completed during the long-term phase compared with the initial 12-wk phase of the program, and supervised SET sessions can occur continuously for ≥48 sessions/wk.
It is important that home-based exercise sessions match SET sessions as closely as possible.28
Because a Medicare-insured patient is limited to 72 SET sessions during their lifetime, consideration for each individual patient should be made regarding whether to use all those sessions at once, or to save them if the patient requires SET in the future. One avenue of thought is to use them all at the initial referral so that patients can maximize their improvement and potentially learn to exercise long-term. In addition, there is no guarantee that a patient will ever be able to use remaining sessions in the future because of financial or health situations. Another avenue of thought is to save the sessions. An example would be to discharge patients from SET once they have demonstrated sufficient improvement (to be defined by the patients) and are able to independently exercise. Another example might be to transfer to a maintenance program (eg, phase 3) to save SET sessions. This latter suggestion, in most cases, would be a less expensive out-of-pocket cost for the patient (eg, SET session copay ∼$11.50 vs typical maintenance program cost of $50–60/mo).
EXAMPLES OF THE PAD PATIENT IN “REAL-LIFE” SET
The clinical exercise professional is regularly presented with several challenges over the course of a SET program. Often, the first and most challenging aspects are establishing the proper initial exercise prescription and the overall evaluation of the initial SET sessions. The exercise goals of the first two SET sessions are to (1) establish the primary exercise modality to be used during the SET program, and (2) determine the proper intensity where mild to moderate pain/discomfort (2-3/4) (Table 1 ) develops within 5-10 min of exercise for modalities that induce pain/discomfort.20 , 29
EXAMPLE 1: APPROPRIATE USE OF MULTIMODAL AEROBIC EXERCISE
Following the first two SET sessions, it is essential for the clinical exercise professional to review the exercise logs to determine the primary exercise modality in subsequent SET sessions. To accomplish this, attention should be focused on absolute exercise intensity (metabolic equivalent task [METs]), durations of exercise and rest bouts, and total exercise time. For instance, if an individual performs treadmill exercise and has a pattern of low intensity (ie, <2.5 METs) and short walking bouts (<5 min), it is important to prescribe multimodal aerobic exercise instead of treadmill exercise alone.29 https://links.lww.com/JCRP/A412 23 , 29
EXAMPLE 2: ESTABLISHING THE CORRECT INTENSITY FOR EXERCISE MODALITIES THAT INDUCE CLAUDICATION
Determining the intensity that produces mild to moderate (2-3/4 rating; see Table 1 ) pain/discomfort during walking (or other exercise) within 5-10 min requires both a review of the exercise history of the patient and a trial-and-error approach.29 https://links.lww.com/JCRP/A412
EXAMPLE 3: PROLONGED REST PERIODS
Careful consideration of the length of rest intervals, particularly in the initial several SET sessions, can help achieve a maximal dose of exercise. The typical amount of time for pain/discomfort to dissipate following exercise to mild to moderate pain ranges between 2 and 5 min and may depend on patient perception of pain, disease severity, pain severity during exercise, and method of rest (eg, sitting vs standing). In Supplemental Digital Content 3, available at: https://links.lww.com/JCRP/A412
EXAMPLE 4: “I DON'T THINK MY WALKING IS GETTING BETTER” VERSUS “THE TRUE NON-RESPONDER”
It is not unusual for patients to become frustrated with progress during SET, particularly during interval exercise. Patients may focus on the lack of increase in bout (interval) duration and may not recognize that progression in exercise intensity is designed to keep bout durations within 5-10 min. In this event, the clinical exercise professional should listen to the patient concerns and utilize the exercise logs to demonstrate potential changes in exercise intensity that the patient may have not considered. Alternatively, repeating the exercise prescription of the first SET session is an excellent practical method to demonstrate improvement in walking bout duration. This is demonstrated in Supplemental Digital Content 4, available at: https://links.lww.com/JCRP/A412 https://links.lww.com/JCRP/A412
An example of lack of improvement is depicted for patient B where a review of the exercise logs showed no change in total exercise time and intensity (METs). As for patient A, the first walking bout of session 1 was repeated at the beginning of the 13th session. However, in the case of patient B, there was only a 22-sec improvement in walking time to mild to moderate pain when repeating the session 1 exercise prescription. As a result, the exercise prescription of patient B was switched from a treadmill only modality to multimodal aerobic exercise including both treadmill and total body recumbent stepping. This is a suggested practice in those showing little improvement during walking.10
MISINTERPRETATION OF THE EXERCISE PRESCRIPTION FOR INTERVAL TRAINING MODALITIES
Finally, it is important for the clinical exercise professional to closely review the duration of exercise bouts recorded in patient exercise logs, particularly in patients allowed to independently determine when to stop walking, and intensity progression. When performing exercise that induces pain, it is a common misinterpretation by the patient to exercise for a specific bout duration and not into mild to moderate pain. Since the goal in this type of exercise is to induce mild to moderate pain/discomfort within 5-10 min, look for exercise logs that are continuously displaying bout durations of 5 or 10 min.
PAYMENT AND REIMBURSEMENT
Although most insurance carriers now consider SET for those with symptomatic PAD to be a reimbursable service, there are questions, issues, and concerns relative to coverage determinations, out-of-pocket expenses, and potential for low adherence and nonparticipation. This section reviews the general reimbursement rules and provides other payment information.
As stated, CMS reimburses for SET services for Medicare beneficiaries with symptomatic PAD. Well-established evidence for the benefit of SET with this population led to the CMS coverage policy in 2017.5
The Medicare regulation is the National Coverage Determination (NCD) 20.35 (5-25-2017), Supervised Exercise Therapy for Symptomatic Peripheral Artery Disease. Within this document, the following expectations are outlined for the physician referral of an eligible patient to a SET program:
The patient must have a face-to-face visit with the physician to obtain a referral to SET.
The patient must receive information at the office visit regarding PAD risk factor reduction and cardiovascular disease; this may include education, counseling, behavioral interventions, and outcome assessments.
The NCD also outlines requirements specifically for the SET program, which have been provided elsewhere in this document.
Although SET can be provided in a CR program setting, by the same staff, and concurrent with a CR session, it is important to recognize that SET is a separate service from CR. Each program (CR and SET) has a distinct coverage provision. For example, CR requires a monthly individualized treatment plan (ITP) with exercise, educational, and assessment components. Supervised exercise therapy does not require this. As noted previously, education/counseling for PAD is the responsibility of the referring physician. Although both CR and SET services may be delivered concurrently and in the same space with the same qualified staff, it would not be clinically logical for a patient to receive CR and SET at the same time. Clinical need should determine which treatment takes precedence. It would be clinically appropriate for a patient with qualifying diagnoses for both CR and for SET to enroll in and complete one program (typically CR) and then follow with SET if CR training did not resolve claudication and symptoms continue to justify a course of SET.
Another stipulation in the SET NCD that merits clarification is that Medicare Administrative Contractors have the discretion to cover SET beyond 36 sessions over 12 wk and may cover up to an additional 36 sessions with a new referral order, but not exceeding 72 sessions, over an extended period. Keep the points in Table 3 in mind when interpreting coverage by Medicare.
Table 3 -
Considerations for Interpreting Insurance Coverage
a
CMS limits SET to a maximum of 72 sessions in the “Medicare lifetime” of a beneficiary.
CMS uses the HIPAA Eligibility Transaction System (HETS) software to track Medicare services that are capped. SET for PAD and pulmonary rehabilitation are two examples of such services.
HETS initially displays 72 SET sessions on provider query screens for all Medicare beneficiaries. Hospital billing departments have access to this information.
As sessions are used, HETS displays the remaining number of SET sessions left. There can be a 1- to 2-mo lag in the accuracy of the HETS sessions count.
When 72 SET sessions have been delivered, any further claims to FFS Medicare will be denied, with or without a qualifying diagnosis for SET.
Medicare Advantage Organizations (MAOs) process and pay their own claims. It is plan-specific whether the KX modifier rule is followed and whether the total number of sessions in the “Medicare lifetime” of a beneficiary is limited.
It is suggested to ask each patient whether he or she has had SET sessions previously for his or her PAD. If they respond “yes,” it is recommended to investigate how many sessions are remaining using HETS. A hospital or clinic billing office should be able to determine this information.
It is at the MAC discretion, retroactively, whether more sessions will be reimbursed beyond the “up-to-36 session” course or beyond the 12-wk time frame (ie, extra 36 visits over 24 or 36 wk).
A second referral is required for these additional sessions.5
The inclusion of a KX modifier on the claim is attestation by the provider of the services that documentation is on file verifying that further treatment beyond the 36 sessions and/or over 12 wk meets the requirements of the medical policy.30
Retroactive claims that are denied by the MAC are the financial responsibility of
Various commercial insurances will have their own coverage conditions.
For commercial payors, consider performing a “coverage determination” before enrolling a patient in SET.
Abbreviations: ABN, advanced beneficiary notice; CMS, Centers for Medicare & Medicaid; FFS, fee-for-service; HIPAA, Health Insurance Portability and Accountability Act; MAC, Medicare Administrative Contractors; PAD, peripheral artery disease; SET, supervised exercise therapy.
a Each bullet provides information to consider when assessing individual patient insurance coverage for SET and when making determinations to extend visits beyond the initial 36.
There is one procedure code (CPT 93668) available for SET services, which may be used one time/d.31 International Classification of Diseases, Tenth Revision (ICD-10 ) codes can be found in published Medicare regulations for SET.31
A major barrier to adherence to a SET program is Medicare and Medicare Advantage plan copayments. These patient costs are incurred per session and are in the range of $11 to $12. For beneficiaries with a lower socioeconomic status, and others, it is a deterrent to completion. Research indicates a higher prevalence of PAD in this subset of patients, possibly due to an increased prevalence of cardiovascular risk factors and poor access to health care.32
REFERRAL PROCESSES AND PROGRAM BEST PRACTICES
Divakaran et al33 ICD-10 coding. Of these, only 1735 (1.3%) enrolled in a SET program and had ≥1 billable session. And of these, the median sessions performed was 16 (IQR: 6, 28), and only 89 (5.1% of those enrolled) completed the full allotment of 36 sessions. Those who enrolled (vs not enrolled) were slightly older (74 ± 8 vs 73 ± 9 yr; P = .02), more likely to be White (87% vs 84%), less likely to be Black (9% vs 11%) and female (39% vs 43%), and less likely to be dually enrolled in Medicaid (13% vs 22%). Most enrollees were from the Midwest (48%) and Northeast (16%) regions of the United States. These data suggest that age, race, sex, and socioeconomic status may play a role in enrollment to SET. A possible limitation of this early data is a low availability of programs providing SET. Although this remains a barrier to participation, there has been an increase in locations offering SET across the United States.
Using CMS data for 2020, 30 945 claims were submitted to CMS for SET through November 23, 2020.34
Although the article by Divakaran et al did not report on SET program referral rates, it is likely that this rate is low.33
Although CMS lists several deliverables that must be provided during SET (eg, 30- to 60-min sessions of therapeutic exercise training; delivered by qualified auxiliary personnel trained in exercise therapy for PAD; under the direct supervision of a physician or advanced practice practitioner) that align with CR, they are silent on several other items that are considered best practices for CR. These would seem to reasonably apply to patients performing SET in the CR setting and include an adequate patient-to-staff ratio and the use of an individualized treatment plan to target behavior change and risk factor reduction. Important areas of focus for the individualized treatment plan would be exercise, smoking cessation, and diabetes management with the latter two being the most important risk factors in these patients relative to disease progression. Also note that CMS allows advanced practice practitioners to provide the required direct supervision for SET services, different than the current requirement for CR, which changes in 2024 to allow advanced practice practitioners the same ability. Regarding the patient-to-staff ratio, it is likely in many instances that this ratio is lower than the 4:1 or 5:1 often considered the norm in CR, although this can vary on the basis of patient factors (age, frailty, ambulatory independence, etc). Because of the specific intermittent exercise training typically performed, there is often a need for a 1:1 staffing ratio, particularly during the initial several SET sessions. This is because patients need to learn the atypical exercise, rest, and intensity progression process used in most SET programs. Once a patient adequately learns and can apply this process, he or she likely will not require as much staff attention. However, some patients may never reach this level of independence.
SUMMARY
Improvement in walking performance is a universally accepted benefit of SET for those with claudication. Supervised exercise therapy has been an insurance-reimbursed therapy since mid-2017 in the United States. Although referral rates are unknown, but likely low, participation rate of eligible patients is assuredly low. Barriers include poor accessibility to locations offering SET, transportation, and cost (eg, copay). These issues were similar in the past in CR and have, to some degree, been overcome, although CR participation is still low. Education of CR programs currently not offering SET and physicians who see eligible patients but do not refer are two areas in which strategies may be focused to help overcome barriers to participation in SET. Ongoing research is a must as there is a paucity of SET-related presentations at national vascular surgery, vascular medicine, and cardiology meetings. Finally, a national PAD awareness campaign by the American Heart Association was released on May 25, 2022 (https://professional.heart.org/-/media/PHD-Files-2/Science-News/p/PAD-National-Action-Plan.pdf
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