Which CAD patient should be referred for cardiac rehabilitation?

I. Cardiac Rehabilitation: What every physician needs to know.

Cardiac rehabilitation (CR) is generally defined as a medically supervised secondary prevention program for patients with established cardiovascular disease (CVD). The goal of this comprehensive long-term program is to help patients with CVD to recover more quickly after a cardiac event and to reduce the risk of future cardiac illness. The services encompass several areas of rehabilitative care:

  • Baseline medical evaluation;

  • Prescribed exercise;

  • Cardiac risk factor modification;

  • Education, counseling, and psychosocial management.

II. Diagnostic Confirmation: Is the patient eligible for Cardiac Rehab?

Under the Centers for Medicare and Medicaid Services (CMS) guidelines, a coronary patient with one or more of the following conditions is eligible for CR services:

  • Acute myocardial infarction (MI) within the preceding 12 months;

  • Coronary artery bypass surgery;

  • Current stable angina pectoris;

  • Percutaneous coronary intervention.

  • Stable, chronic heart failure with left ventricular ejection fraction <35% and New York Heart Association class II to IV symptoms despite being on optimal medical therapy for at least six weeks

III. Benefits of Cardiac Rehab

The specific benefits of this multifactorial approach are to:

Limit the physiologic and psychological effects of cardiac illness;

  • Reduce the risk of sudden cardiac death or reinfarction;

  • Control cardiac symptoms;

  • Stabilize or reverse the atherosclerotic process;

  • Improve the psychosocial and vocational status.

Depending on the type of initial cardiac event and the individual circumstances, the rehabilitation process may have different goals for each patient. Certain categories of patients may benefit particularly from a specific component of CR.

In addition to reductions in recurrent MI and mortality, exercise training is likely to enhance functional capacity. Therefore, supervised exercise training may be most beneficial for individuals who have not previously exercised or those with low functional capacity, such as many elderly patients. In particular, for patients with angina – either in the office or following a hospitalization – exercise training may be considered an additional anti-anginal intervention, as exercise training increases the activity threshold before the onset of symptomatic ischemia. Finally, patients who might be anticipated to develop symptoms with exercise and those who are anxious about exercise will likely benefit from the surveillance and reassurance a supervised exercise program provides.

Patients with uncontrolled cardiovascular risk factors will benefit from interventions that specifically target these risk factors, either by counseling regarding lifestyle modifications or by the use of evidence-based preventive medications.

The education and counseling component of CR is important for all areas of rehabilitative care. Certainly depressed patients, patients who have not previously had experience with medication-taking, and patients with multiple comorbidities may gain particular benefit from this aspect of CR.

The more components of a comprehensive secondary prevention program are adopted for a patient, the more likely the outcomes will improve. Thus, even patients with barriers to CR should adhere to as many components as possible.

IV. Timing of Cardiac Rehabilitation Services

CR services have historically been divided into 3 main phases:

  • Inpatient phase/ Phase I

  • Early outpatient phase/ Phase II

  • Long-term outpatient phase/ Phase III

The inpatient phase consists of early graded mobilization of the stable cardiac patient to the level of activity required to perform simple household tasks.

Early outpatient CR ideally occurs promptly following the hospitalization and usually within the first 3 to 6 months after the index event. It commonly includes supervised physical exercise. It also is the phase with the most data showing reduced risk of CVD mortality among its participants and is considered the traditional structured CR program. This early outpatient phase of CR at clinical centers has now become the standard of care by which patients with CVD are restored to their optimal physical, medical, vocational, and psychosocial status. Most medically supervised outpatient programs consist of three times weekly ECG-monitored exercise sessions for 8 to 12 weeks, and sometimes longer.

The long-term phase has the goal that the patient can exercise independently and maintain the principles learned during phase II.

Secondary prevention strategies are most beneficial when initiated soon after the index hospitalization, but due to clinical, social, and logistical reasons there are often delays. Optimally, CR is initiated 1 to 3 weeks after hospital discharge.

One of the main barriers to ensure patient attendance in a CR program is to persuade patients of their need to go to CR sessions. Waiting longer than 3 weeks to refer a patient to a CR program may diminish the patient’s memory of the index event and a patient may be less likely to enroll.

Many third-party payers allow CR services to begin up to 6 to 12 months following a cardiac event. Therefore, health care providers responsible for the referral of patients to a CR program include not only hospital staff but also outpatient physicians with primary responsibility for the care of patients after a CVD event.

The index hospitalization offers a unique opportunity to educate the patient and initiate the referral process to an outpatient CR program. If this has not occurred, it is the responsibility of the outpatient provider to ensure patient referral.

Patients with barriers to structured CR services may participate in modified CR programs that adapt their services to the patient’s limitations. Before hospital discharge it is important to assess and document a patient’s risk for adverse events during exercise. It is good practice to provide the patient with an exercise prescription that accompanies the outpatient CR referral.

V. Requirements for a CR program

Medical evaluation

At program entry, a medical and surgical history are obtained and recent cardiovascular tests are reviewed (e.g., 12-lead ECG, coronary angiogram, stress test, echocardiogram). Comorbidities, functional limitations, cardiovascular risk factors, and current medications are reviewed and documented. It should be ascertained that the patient is taking appropriate doses of cardioprotective drugs that have evidence-based efficacy for secondary prevention as per American College of Cardiology/ American Heart Association guidelines.

Knowledge of clinical symptoms, coronary anatomy and revascularization status, left ventricular systolic function, as well as the presence and the degree of residual myocardial ischemia is crucial to determine the risk for cardiovascular complications of exercise.

The patient’s functional status at baseline, including activities of daily living and exercise capacity, both occupational and recreational, should be ascertained and serve to guide the desired level of activity the patient may reach after program completion. This baseline encounter can also serve as an opportunity to ensure that the patient receives an annual influenza vaccination.

Psychosocial assessment

The patient’s mental and emotional functioning should be assessed as it relates to the individual’s rehabilitation. This typically includes an evaluation of the family and home situation. Further, it encompasses identification of depression, anxiety, anger or hostility, social isolation, family distress, sexual dysfunction, and substance abuse using standard interview and measurement techniques. A large number of CAD patients are depressed, and their families are typically apprehensive about allowing them to partake in life’s activities.

Physician-prescribed and physician-supervised exercise

The exercise program consists of aerobic exercise supplemented with other types of exercise (i.e., strengthening, stretching) as determined appropriate for the individual patient. Symptom-limited exercise testing may be helpful before enrollment in an exercise-based CR program, with exercise test performance guiding the level of supervision during the rehabilitation session. Patients can be classified into four groups depending on their cardiovascular risk:

  • Class A individuals are apparently healthy and have no increased cardiovascular risk with exercise;

  • Class B identifies patients with clinically stable CVD who are considered at low risk of cardiovascular complications with vigorous exercise;

  • Class C individuals are considered to be at moderate or high risk of cardiac complications during exercise and comprise patients with a history of multiple myocardial infarctions, left ventricular dysfunction or cardiac arrest, New York Heart Association functional class III or an exercise capacity of <6 metabolic equivalents, or significant ischemia at exercise testing

  • Class D patients are those with unstable CVD or decompensated symptomatic heart failure, for whom exercise is contraindicated.

The typical patients referred for an outpatient exercise-based CR program are in class B or C. Patients from each risk class require differing extents of exercise monitoring or supervision. Class C patients are recommended to participate in a medically supervised exercise program for at least 8 to 12 weeks after an acute event, until the safety of the prescribed exercise regimen has been established. Although low-risk patients (class B) may initially benefit from medically supervised exercise (3 to 4 weeks), self-monitored home-based exercise programs have also been documented to be effective and safe.

Cardiac risk factor modification

In a CR program, patients will learn how to make changes in lifestyle and to use preventive medications as indicated and necessary. Patients will undergo counseling regarding nutrition and physical activity. They will be advised on management of weight, blood pressure, and blood lipids. Smoking status and the presence or absence of diabetes should be confirmed and adequately addressed. Education and counseling provided by CR programs are especially important because of the limited time available during the initial hospitalization and the brief outpatient physician visits now customary in current clinical practice.

Individualized treatment plan and outcomes assessment

According to CMS guidelines, a CR treatment plan should be written and tailored to each individual patient and reviewed by a physician every 30 days. This plan includes:

  • A description of the individual’s diagnosis.

  • The type, amount, frequency, and duration of the CR services.

  • The goals set for the individual patient.

The outcomes assessment includes objective clinical measures of the effectiveness of the CR program for the individual patient, such as exercise performance and self-reported measures of exertion and functional capacity.

VI. Safety of exercise

The risk of sudden death or acute myocardial infarction during exercise in patients with coronary disease is mainly a function of the baseline fitness level. The least active patients are 50 times more likely to incur an event during exercise than the most active patients. In medically supervised cardiac rehabilitation programs, the incidence of death appears generally very low. Contemporary exercise-based CR programs report a risk of any major cardiovascular complication (cardiac arrest, death or MI) as one event in 60,000 to 80,000 hours of supervised exercise. The presence of skilled providers for adult cardiovascular life support as well as pre-participation screening of patients may explain these favorable data.

No randomized controlled studies have been conducted to define strategies against exercise-induced cardiovascular events. The available data suggest that maintaining an adequate fitness level is a critical protective factor. Thus, an important aspect of supervised physical activity is to build up a patient’s fitness level and to develop and teach an individualized exercise prescription that is both safe and effective. This makes it less likely that the patient will be exposed to unaccustomed activity afterwards as long as fitness level is maintained.

Patients may exercise without supervision when they understand safety issues during exercise, including warning signs and symptoms, and after they have learned how to monitor their own activity levels. They are taught to guide exercise intensity by heart rate and rating of perceived exertion.

There are several ways to assess the risk of physical exercise after a cardiovascular event. The traditional submaximal stress test between day 2 and day 5 after the event is only rarely performed nowadays. It may be helpful for patients who present late after an ST-elevation MI. The main endpoints of a submaximal stress test include a peak heart rate of 120 to 130 bpm or 70% of maximal predicted heart rate for age, a peak work level of 5 metabolic equivalents (METs), or clinical or ECG end points of mild angina or dyspnea, ST-segment depression greater than 2 mm, exertional hypotension, or 3 or more consecutive premature ventricular contractions, whichever end point is reached first.

This test permits detection of profound ischemia that could be associated with cardiac events that might occur before a scheduled 3- to 6-week postdischarge, symptom-limited stress test. If this test is abnormal, the patient should undergo invasive testing and possible revascularization. If normal, it provides psychological benefits to the patient.

A symptom-limited stress test is performed without stopping for a predefined physiological end point such as target heart rate or MET level. The optimal timing for a symptom-limited stress test is not completely clear, but should not be done earlier than 5 days after an ST-elevation MI. The cardiovascular complication rate is about 2 times higher for a symptom-limited exercise test than for a submaximal test. The safety of early symptom-limited exercise testing is based on relatively limited data, and clinical judgment must be used. Most symptom-limited exercise tests are performed approximately 2 to 3 weeks after the index event.

At this time, it enables more optimal assessment of functional capacity, and the test results can be used to establish intensity and target heart rate during CR. Until safe exercise levels have been determined, it is prudent to caution patients to avoid performing unaccustomed vigorous physical activity and to recommend gradual increases in physical activity over time.

VII. Delivery of exercise training

The patient should be free to choose the most enjoyable mode of exercise involving large muscle groups such as walking, jogging, cycling, rowing, machine stair climbing, and other endurance activities.

Exercise intensity is commonly categorized using the percent of the peak heart rate (PHR) achieved during a symptom-limited exercise test. Exercise is considered light in intensity as long as the heart rate remains <60% of PHR. Activity that produces 60%–80% of PHR corresponds to moderate exercise levels, while heavy exercise is any heart rate above 80% of PHR. The intensity and duration of exercise determine overall energy expenditure.

An individualized exercise prescription should incorporate aerobic and resistance training and should consider specific patient comorbidities.

The exercise training sessions should include 5-10 minutes of warm-up and 5-10 minutes of cool-down time. The conditioning or training phase usually lasts 30-45 minutes and should also incorporate flexibility exercises. Throughout the course of CR, the exercise prescription is progressively updated as clinical status changes. Exercise programs generally begin with light intensity exercise and gradually progress.

The clinical trial evidence for the benefits of exercise in reducing cardiovascular events or mortality is limited. Much of the evidence for the benefit of exercise for cardiovascular health comes from long-term observational studies. In regard to CR, it appears to be a combination of exercise and secondary prevention measures that leads to improved patient outcomes. Exercise-based CR also improves functional capacity, which may help individuals return to work and improve quality of life.

For elderly patients and patients with significantly reduced baseline functionality, the beneficial effects of CR may contribute to maintaining independent living.

VIII. Alternate approaches to referral for Cardiac Rehabilitation

To rectify the unacceptable underuse of CR programs in contemporary medical practice, alternative models to traditional clinic- and hospital-based CR programs have been suggested.

Home-based CR is defined as a structured program with clear objectives for the participants, including monitoring, follow-up, visits, letters, telephone calls from staff, or at least self-monitoring diaries.

Center-based CR is a supervised group-based program undertaken in a hospital or community setting such as a sports center. Home-based and community-based rehabilitative programs appear safe and effective for stable patients with CVD.

A Cochrane meta-analysis has shown that home-based and medically supervised forms of CR seem to be equally effective in improving clinical and health-related quality of life outcomes in patients at low risk after cardiovascular events. This provides treating physicians with alternate approaches to referral for CR services for patients unable to afford or with limited access to center-based CR programs. Nevertheless, home-based CR programs have not been widely implemented and are currently not covered by CMS guidelines.

A recent AHA science advisory calls on the inpatient and home health teams to implement a coordinated effort to facilitate outpatient CR enrollment. A key recommendation of this advisory is to promote a better understanding of outpatient CR as a multidisciplinary secondary prevention program and not just an exercise program that might discourage patients with comorbidities.

A meta-analysis of 63 randomized trials examining a wide variety of secondary prevention programs found significant reduction in recurrent MI and all-cause mortality. Interestingly, these beneficial effects were similar for programs that included risk factor education with a structured exercise component, for programs that included risk factor education without an exercise component, and for programs that were solely exercise-based. Furthermore, benefits were similar in recently published trials compared to those before the widespread use of contemporary medical and revascularization therapies.

CMS now reimburses an alternative CR intervention program, designated intensive CR (ICR), which furnishes CR more frequently and often in a rigorous manner. This means up to 72 one-hour sessions, up to 6 sessions per day, over a period of up to 18 weeks as opposed to 36 sessions, up to 2 one-hour sessions per day, over a period of up to 36 weeks with the option of an additional 36 sessions over an extended period of time for a traditional CR program.

IX. Performance Measures

In recent years there has been increasing focus on improving the quality of healthcare. Clinical practice guidelines are designed to help clinicians synthesize available evidence and provide recommendations for diagnostic and therapeutic interventions for patients in most situations. Adopting guidelines to the care of individual patients still requires careful clinical judgment. Nevertheless, certain aspects in the process of care may be so important that failure to perform such steps likely results in suboptimal patient outcomes. Such specific actions should therefore be adopted for every patient unless individual circumstances are prohibitive.

Adherence to guideline recommendations can serve as an internal quality control, but can also be quantified as a provider performance measure. One such aspect in the care of patients with cardiovascular disease (CVD) is referral of eligible patients to a CR program. Data from recent years show that CR services remain as beneficial as they were in the pre-revascularization era. Even though mortality from CVD has declined over the past several decades, morbidity and subsequent disability remain high. Newer treatment options for patients with acute cardiovascular events have reduced case fatality and led to an increased number of survivors who require long-term medical follow-up and lifelong secondary prevention.

Most cardiology associations, including the American College of Cardiology (ACC) and the American Heart Association (AHA), have endorsed the use of CR services in their practice guidelines. All recent ACC/AHA coronary guidelines have elevated CR to a class IA recommendation because of the accumulating evidence for benefit.

Outpatient CR has been shown to significantly reduce the morbidity and mortality of patients with CVD compared with usual care. Despite this, CR remains vastly underutilized. Current statistics show that fewer than 30% of eligible US patients are referred to exercise CR following a cardiovascular event. Women, minorities, and elderly patients are particularly underrepresented in CR programs. Patients with comorbidities, less medical insurance coverage, and longer geographic distance to CR program sites are also less likely to participate. In 2007, a CR performance measure set was implemented with the intent to improve delivery of CR to patients with CVD. In addition to its implications for the prognosis and quality of life of every affected patient, morbidity after cardiovascular events is a significant socioeconomic burden. Both hospitals at discharge and office practices may soon be asked to be accountable to these various performance measures.

Thus, not only patients but also healthcare providers have to be educated about CR benefits; and health care system and societal barriers to CR referral have to be addressed. To help health care groups identify potentially correctable causes of suboptimal clinical care, the performance measures are structure-based (relating to facilities, personnel and equipment) and process-based (relating to specific program components, such as a comprehensive, standardized list of cardiovascular risk factors for every patient upon entry into the CR program).

X. What's the evidence for specific management and treatment recommendations? (Annotated bibliography)

Thomas, RJ, King, M, Lui, K. “AACVPR/ACC/AHA 2007 performance measures on cardiac rehabilitation for referral to and delivery of cardiac rehabilitation/secondary prevention services endorsed by the American College of Chest Physicians, American College of Sports Medicine, American Physical Therapy Association, Canadian Association of Cardiac Rehabilitation, European Association for Cardiovascular Prevention and Rehabilitation, Inter-American Heart Foundation, National Association of Clinical Nurse Specialists, Preventive Cardiovascular Nurses Association, and the Society of Thoracic Surgeons”. J Am Coll Cardiol. vol. 50. 2007. pp. 1400-33. (These performance measures are intended to provide practitioners and institutions that deliver CR care with tools to measure the quality of their care and identify opportunities for improvement.)

Clark, AM, Hartling, L, Vandermeer, B, McAlister, FA. “Meta-analysis: secondary prevention programs for patients with coronary artery disease”. Ann Intern Med. vol. 143. 2005. pp. 659-72. (This study shows that outpatient CR improves outcomes of patients with CVD when added to standard therapy.)

Thomas, RJ, King, M, Lui, K. “AACVPR/ACCF/AHA 2010 Update: Performance Measures on Cardiac Rehabilitation for Referral to Cardiac Rehabilitation/Secondary Prevention Services Endorsed by the American College of Chest Physicians, the American College of Sports Medicine, the American Physical Therapy Association, the Canadian Association of Cardiac Rehabilitation, the Clinical Exercise Physiology Association, the European Association for Cardiovascular Prevention and Rehabilitation, the Inter-American Heart Foundation, the National Association of Clinical Nurse Specialists, the Preventive Cardiovascular Nurses Association, and the Society of Thoracic Surgeons”. J Am Coll Cardiol. vol. 56. 2010. pp. 1159-67.

Corté s, O, Arthur, HM. “Determinants of referral to cardiac rehabilitation programs in patients with coronary artery disease: a systematic review”. Am Heart J. vol. 151. 2006. pp. 249-56.

Witt, BJ, Jacobsen, SJ, Weston, SA. “Cardiac rehabilitation after myocardial infarction in the community”. J Am Coll Cardiol. vol. 44. 2004. pp. 988-96.

Suaya, JA, Shepard, DS, Normand, SL. “Use of cardiac rehabilitation by Medicare beneficiaries after myocardial infarction or coronary bypass surgery”. Circulation. vol. 116. 2007. pp. 1653-62.

Wenger, NK, Froelicher, ES, Smith, LK. “Cardiac rehabilitation as secondary prevention. Agency for Health Care Policy and Research and National Heart, Lung, and Blood Institute”. Clinical Pract Guidel Quick Ref Guide Clin . vol. 1. 1995. pp. 23

Wenger, NK. “Current status of cardiac rehabilitation”. J Am Coll Cardiol. vol. 51. 2008. pp. 1619-31.

Thompson, PD, Franklin, BA, Balady, GJ. “Exercise and acute cardiovascular events placing the risks into perspective: a scientific statement from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism and the Council on Clinical Cardiology”. Circulation. vol. 115. 2007. pp. 2358-68.

Burke, AP, Farb, A, Malcom, GT. “Plaque rupture and sudden death related to exertion in men with coronary artery disease”. JAMA. vol. 281. 1999. pp. 921-6.

Cobb, LA, Weaver, WD. “Exercise: a risk for sudden death in patients with coronary heart disease”. J Am Coll Cardiol. vol. 7. 1986. pp. 215-9.

Squires, RW, Gau, GT, Miller, TD. “Cardiovascular rehabilitation: status, 1990”. Mayo Clin Proc. vol. 65. 1990. pp. 731-55.

Mittleman, MA, Maclure, M, Tofler, GH. “Triggering of acute myocardial infarction by heavy physical exertionProtection against triggering by regular exertion. Determinants of Myocardial Infarction Onset Study Investigators”. N Engl J Med. vol. 329. 1993. pp. 1677-83.

Fletcher, GF, Balady, GJ, Amsterdam, EA. “Exercise standards for testing and training: a statement for healthcare professionals from the American Heart Association”. Circulation. vol. 104. 2001. pp. 1694-740.

Antman, EM, Anbe, DT, Armstrong, PW. “ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction; A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction)”. J Am Coll Cardiol. vol. 44. 2004. pp. E1-E211.

Balady, GJ, Ades, PA, Bittner, VA. “Referral, enrollment, and delivery of cardiac rehabilitation/secondary prevention programs at clinical centers and beyond: a presidential advisory from the American Heart Association”. Circulation. vol. 124. 2011. pp. 2951-60. (Presidential advisory from the AHA that highlights opportunities to expand CR services through novel methods of delivery.)

Dalal, HM, Zawada, A, Jolly, K. “Home based versus centre based cardiac rehabilitation: Cochrane systematic review and meta-analysis”. BMJ. vol. 340. 2010. pp. b5631

Arena, R, Williams, M, Forman, DE. “Increasing referral and participation rates to outpatient cardiac rehabilitation: the valuable role of healthcare professionals in the inpatient and home health settings: a science advisory from the American Heart Association”. Circulation. vol. 125. 2012. pp. 1321-9. (Science advisory from the AHA that emphasizes that home health care services can facilitate a patient's transition to CR programs.)

XI. DRG Codes

Hospitals that provide CR services have to be in compliance with associated transmittals and federal regulations prior to billing for the services. As phase I CR is initiated in the acute care setting following a cardiac event, it is usually covered but not separately payable, as it is included in the inpatient payment, such as an MS-DRG.

Transmittals refer to outpatient CR programs only. Unlike CR, intensive CR (ICR) programs must be approved by CMS through the National Coverage Determination process after meeting very specific criteria. Once ICR programs are approved through this process, individual sites wishing to furnish ICR services via an approved ICR program may enroll with their local Medicare contractor as ICR program suppliers. Once a patient begins CR, he or she may not switch to ICR and vice versa. Upon completion of either program, the patient must experience another indication to be eligible for more CR or ICR.

  • CR without continuous monitoring: HCPCS 93797

  • CR with continuous monitoring: HCPCS 93798

  • ICR with exercise: HCPCS G0422

  • ICR without exercise: HCPCS G0423