Introduction
Evidence-based treatments for patients with myocardial infarction (MI) have improved outcomes, with substantive reductions in mortality rates ( Chapter 2 ). Nevertheless, patients who survive an acute MI remain at increased risk for recurrent MI and death and also suffer from clinical symptoms and loss of physical, psychological, or social functioning after discharge that can lead to impaired health-related quality of life. The effectiveness and accessibility of cardiac rehabilitation and secondary prevention services after MI have therefore never been more important. Current international clinical guidelines, including those of the American Heart Association, the American College of Cardiology, and the European Society of Cardiology, endorse rehabilitation and secondary prevention as key elements of standard post-MI management.
Our approach to post-MI rehabilitation has changed radically in the last 80 or so years. In the 1930s, restriction of physical activity and prolonged bed rest were standard of care for patients suffering from an MI. Subsequent evolution of practices such as chair therapy (1940s), brief daily walks of 3 to 5 minutes (1950s), and structured inpatient cardiac rehabilitation programs for early ambulation after MI (1960s) led to the development of today’s multidisciplinary, comprehensive cardiac rehabilitation and secondary prevention programs for a broad group of patients with atherosclerotic cardiovascular disease.
The following definition from the Agency for Health Care Policy and Research encompasses these contemporary concepts:
Cardiac rehabilitation [and secondary prevention] services are comprehensive, long-term programs involving medical evaluation, prescribed exercise, cardiac risk factor modification, education, and counselling. These programs are designed to limit the physiologic and psychological effects of cardiac illness, reduce the risk for sudden death or re-infarction, control cardiac symptoms, stabilize or reverse the atherosclerotic process, and enhance the psychosocial and vocational status of selected patients. 6a
Although exercise training remains a cornerstone of intervention, current practice guidelines consistently recommend “comprehensive rehabilitation” programs that should contain the necessary core components to optimize cardiovascular risk reduction, foster healthy behaviors and compliance with these behaviors, reduce disability, and promote an active lifestyle.
Cardiac rehabilitation and secondary prevention services should begin in the inpatient setting for patients who have survived an acute MI and continue into the early-outpatient and late-outpatient phases of follow-up ( Figure 34-1 ). Although in many countries this inpatient and early-outpatient care is covered by health care providers and insurers, the costs of late-outpatient or “maintenance” programs often need to be met by the patients themselves.
This chapter presents the evidence for cardiac rehabilitation and secondary prevention after MI, focusing on the findings of systematic reviews and meta-analyses; details the components of cardiac rehabilitation and secondary prevention delivery using current high-profile international practice and policy statements; and finally, considers current and future key challenges facing rehabilitation and secondary prevention services.
Evidence for Cardiac Rehabilitation and Secondary Prevention
The first systematic reviews and meta-analyses of cardiac rehabilitation were published more than 20 years ago and reported a 20% to 25% reduction in all-cause and cardiovascular mortality in pooled data from 22 randomized controlled trials (RCTs) in more than 4300 post-MI patients, comparing exercise-based cardiac rehabilitation with a no-exercise rehabilitation approach in the control group. A number of updated versions of this systematic review/meta-analysis of cardiac rehabilitation and secondary prevention have since been published.
The 2016 Cochrane systematic review and meta-analysis “Exercise-based cardiac rehabilitation for coronary heart disease” provides a useful summary of the available evidence. The inclusion and exclusion criteria for the 2016 Cochrane review are summarized in Table 34-1 . Bibliographic databases of Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, and Science Citation Index Expanded were searched to July 2014. The study authors identified a total of 63 RCTs ( Table 34-e1 ). Although this update included a total of 14,486 patients, most trials were relatively small in size (median number of patients, 126; range, 28 to 2304). Greater than 80% of the trial populations were post-MI patients, with the remainder consisting of patients who had undergone coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI); in more than one half of the patients in these cohorts, previous MI was the exclusive diagnosis. The median follow-up period was 12 months. Programs typically were conducted in a supervised outpatient hospital/center-based setting, either exclusively or in combination with some maintenance home exercise sessions. Although it was noted that the quality of reporting had improved in more recently published RCTs, overall, the authors judged the various individual categories of study risk of bias as either high or unclear.
| Inclusion |
|
| Exclusion |
|
| Category | No. of Studies (%) or Median ∗ (Range) |
|---|---|
| Study Characteristics | |
| Publication year | |
| 1970-1979 | 2 (3) |
| 1980-1989 | 12 (19) |
| 1990-1999 | 20 (32) |
| 2000-2009 | 21 (33) |
| 2010 onward | 8 (13) |
| Study location | |
| Europe | 37 (59) |
| North America | 12 (19) |
| Asia | 6 (10) |
| Australasia | 5 (8) |
| Other | 2 (3) |
| Not reported | 1 (2) |
| Single center | 45 (71) |
| Sample size | 126 (28-2304) |
| Duration of follow-up | 12 months (6-120) |
| Population Characteristics | |
| Gender | |
| Males only | 18 (29) |
| Females only | 1 (2) |
| Both males and females | 41 (65) |
| Not reported | 3 (5) |
| Age (years) | 56.0 (49.3-71.0) |
| Diagnosis | |
| Post–myocardial infarction only | 31 (49) |
| Revascularization only | 2 (3) |
| Angina only | 5 (8) |
| Mixed-CHD population | 25 (40) |
| Intervention Characteristics | |
| Intervention type | |
| Exercise-only programs | 25 † (38) |
| Comprehensive programs | 39 † (60) |
| Duration of intervention (months) | 6 (1-48) |
| Dose of intervention | |
| Duration | 6 months (1-48) |
| Frequency | 1-7 sessions/week |
| Length | 20-90 minutes/session |
| Intensity |
|
| Setting | |
| Center-based only | 33 (52) |
| Combination of center- and home-based | 13 (21) |
| Home-based only | 15 (24) |
| Not reported | 2 (3) |
† One study includes both exercise-only and comprehensive cardiac rehabilitation (CR) arms.
Meta-analyses showed that cardiac rehabilitation had no effect on total mortality compared with that for the control group but led to a reduction in cardiovascular mortality (relative risk, 0.74; 95% CI, 0.64 to 0.86) ( Table 34-2 and Figure 34-2 ). Exercise-based rehabilitation reduced the risk of hospital admissions (relative risk, 0.82; 95% CI, 0.70 to 0.96) ( Figure 34-e1 ). No significant impact on either the risk of recurrent MI or revascularization was noted. In view of the variation in health-related quality of life outcome measures across trials, meta-analysis for this aspect of outcomes was not possible. Of 20 studies that reported quality of life, however, a majority (13 trials, 65%) showed higher outcome levels in one or more quality of life domains after rehabilitation compared with those for control groups. With data from multiple RCTs and meta-analyses of RCTs, the efficacy of cardiac rehabilitation fulfills grade A/level I evidence.
| Outcome | No. of Participants (with No. of Studies) | No. of Events/ Participants | Relative Risk (with 95% CI) | Statistical Heterogeneity I statistic Chi-Square Test (with P value) | GRADE/Quality of Evidence | |
|---|---|---|---|---|---|---|
| Intervention | Comparator | |||||
| All-cause mortality (all studies) | 12,455 (47) | 838/6424 | 865/6031 | 0.94 (0.87-1.02) | 0% (0.58) | + + + − Moderate ∗ |
| CV mortality (all studies) | 7469 (27) | 292/3850 | 375/3619 | 0.74 (0.64-0.85) | 0% (0.70) | + + + − Moderate ∗ |
| Fatal and/or nonfatal MI (all studies) | 971 (36) | 356/4951 | 387/4766 | 0.89 ( 0.78-1.02) | 0% (0.48) | + + − − Low ∗† |
| CABG (all studies) | 5891 (29) | 208/3021 | 212/2870 | 0.94 ( 0.78-1.12) | 0% (0.86) | + + + − Moderate ∗ |
| PCI (all studies) | 4012 (16) | 171/2013 | 197/1999 | 0.86 (0.71-1.04) | 0% (0.59) | + + + − Moderate ∗ |
| Hospital admissions (all studies) | 3030 (15) | 407/1556 | 453/1474 | 0.86 (0.77-0.95) | 34.5% (0.10) | + + − − Low ∗† |
† Funnel plots and/or Egger test suggest evidence of asymmetry.
| Grade Working Group Quality of Evidence |
| High quality : Further research is very unlikely to change our confidence in the estimate of effect. |
| Moderate quality : Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. |
| Low quality : Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. |
| Very low quality : We are very uncertain about the estimate. |
∗ Random sequence generation, allocation concealment, and blinding of outcome assessors were poorly described in greater than 50% of included studies; bias likely.
In addition to efficacy, two key additional key evidence considerations for rehabilitation and secondary prevention are safety and cost-effectiveness. Exercise-based rehabilitation appears to be very safe. An observational study of more than 25,000 patients in a French registry of rehabilitation-related complications reported one cardiac event for 50,000 hours of exercise training—equivalent to 1.3 cardiac arrests per 1 million patient-hours. An earlier American study reported only one case of ventricular fibrillation per 111,996 patient-hours of exercise and one MI per 294,118 patient-hours. A systematic review of economic evaluations of cardiac rehabilitation and secondary prevention reported a cost per life-year gained ranging from US$2193 to US$28,193. In 2007, the National Institute of Health and Care Excellence (NICE) in the United Kingdom estimated the incremental cost-effectiveness ratio for rehabilitation after MI at approximately £7860 and £8360 per quality-adjusted life-year (QALY) gained for men and women, respectively. NICE’s current funding threshold is £20,000/QALY, indicating the provision of cardiac rehabilitation and secondary prevention to be cost-effective.
Components of Cardiac Rehabilitation and Secondary Prevention
Systematic Referral
All eligible patients with acute MI and all patients in the immediate postoperative period after CABG or PCI should be referred to a comprehensive outpatient rehabilitation and secondary prevention program either before hospital discharge or during the first immediate follow-up visit. The services should be instituted as soon as possible after hospital admission. Cardiac rehabilitation and secondary prevention generally are considered most beneficial when delivered soon after the index hospitalization. In certain situations, however, clinical, social, and logistic reasons can delay enrollment in a structured program. To ensure effective access to rehabilitation and preventive services, referral should be considered by all health care practitioners with responsibility for the care of post-MI patients in the 12 months after their acute event or cardiac surgery.
Despite the substantive evidence for the benefits of such services, implementation of and patient enrollment in cardiac rehabilitation and secondary prevention programs remain below desired levels. Studies in Europe, North America, and Australia have reported participation rates of 20% to 50%. The gap in delivery is especially large in older patients, women, and members of ethnic minorities. Reasons behind these gaps in participation are generally classified into three categories: (1) patient-based, especially lack of sufficient financial resources and/or health care insurance coverage to participate or lack of interest in participating in the program; (2) provider-based, especially lack of physician referral of patients; and (3) system-based barriers, especially lack of resources to fund rehabilitation/preventive services or lack of services within close proximity to a patient’s home. A Cochrane systematic review assessed the efficacy of interventions to improve uptake of and adherence to cardiac rehabilitation and secondary prevention. However, this review found only weak evidence (11 RCTs) supporting specific interventions to increase uptake. Systematic referral procedures and interventions targeting patient-identified barriers may increase the likelihood of success. At referral, clinicians need to be aware of potential patient barriers ( Table 34-3 ). Some particular approaches to overcoming these barriers are presented later under Innovative and Models of Rehabilitation and Prevention (in the section on maintaining long-term behavioral changes).
| Patient-Related Barriers | Provider- and System-Related Barriers |
|---|---|
|
|
Patient Risk Assessment and Tailored Planning
Formulation of an individually tailored, patient-specific plan for cardiac rehabilitation and secondary prevention should be based on a careful risk assessment at discharge or as soon as possible after hospital admission and before initiation of the program. This risk assessment should systematically collect and document the clinical information as listed in Table 34-4 .
| Assessment Component | Description |
|---|---|
| Clinical history | Screening for cardiovascular risk factors, comorbid conditions and disabilities, psychological stress, vocational situation |
| Symptoms | Cardiovascular disease—NYHA functional class for dyspnea and Canadian Cardiovascular Society (CCS) class for symptoms of angina |
| Medication | Including dose, frequency, side effects |
| Adherence | To medical regimen and self-monitoring (weight, BP, symptoms) |
| Physical examination | General health status, body mass index (BMI), waist circumference, heart failure signs, cardiac and carotid murmurs, pulse, BP control, extremities for presence of arterial pulses and orthopedic pathology, neurological abnormalities |
| ECG | Heart rate and rhythm, repolarization |
| Cardiac imaging | 2D and Doppler echocardiography when appropriate—in particular, ventricular function, valvular heart disease, presence of effusion |
| Blood testing | For routine biochemical assay: including full blood count, electrolytes, renal and liver function, fasting blood glucose (HbA 1C if fasting blood glucose is elevated or with known diabetes), total cholesterol, LDL-C, HDL-C, triglycerides |
| Physical activity level by history | Domestic, occupational, and recreational needs; activities relevant to age, gender, and daily life; readiness to change behavior; self-confidence; barriers to increased physical activity; and social support in making positive changes |
| Peak exercise capacity | Symptom-limited exercise testing, either on bicycle ergometer or on treadmill. If this is not feasible (e.g., because of recent surgery), submaximal exercise evaluation and/or six-minute walk test should be considered. |
| Education | Clear, comprehensible information on the basic purpose of the CR program and the role of each component (including optimal medical therapy compliance) Education on self-monitoring protocols (weight, blood pressure, warning symptoms and signs of instability, e.g., angina, dyspnea) and self-management |
Exercise Testing and Training
Symptom-limited exercise testing before participation in an exercise-based cardiac rehabilitation program is strongly recommended (see also Chapter 30 ). Exercise test parameters should include assessment of heart rate and rhythm, signs and symptoms, ST-segment changes, hemodynamics, perceived exertion, and exercise capacity. On the basis of this exercise test, patients can then be risk-stratified to select the appropriate level of supervision and monitoring required during their exercise-based rehabilitation program. Exercise training should incorporate an individualized exercise prescription for aerobic training that should be regularly reviewed by the program team and modified if necessary. Current recommendations for exercise prescription are as follows:
- •
Frequency: 3 to 5 sessions per week
- •
Intensity: 50% to 80% of maximal exercise capacity
- •
Duration: 20 to 60 minutes per session
- •
Modality: walking, treadmill, cycling, rowing, stair climbing, arm/leg ergometry, and other modalities, using continuous or interval training as appropriate
Exercise-based rehabilitation programs also can include resistance exercise.
Education
A Cochrane review identified 13 RCTs examining patient education interventions among 68,556 subjects with coronary heart disease, with a follow-up period of 6 to 60 months. The meta-analysis from this review showed weak evidence of an effect of education compared with usual care on all-cause mortality (relative risk [RR], 0.79; 95% CI, 0.55 to 1.13) and cardiac morbidity (recurrent MI: RR, 0.63; 95% CI, 0.26 to 1.48; revascularization: RR, 0.58; 95% CI, 0.19 to 1.71; and hospitalization: RR, 0.83; 95% CI, 0.65 to 1.07). After education, some evidence indicates that quality of life scores were higher than those in control groups. These findings generally are supportive of cardiac rehabilitation and secondary prevention, including some form of education, either in groups or as individual consultations. Further research into different models of education is needed, however, to inform future more specific recommendations on the nature and content of this education delivery.
Current guidelines for education include its role in providing a positive impact on healthy behavior ( Table 34-5 ), risk factor modification ( Table 34-6 ) and improving adherence to cardioprotective medications ( Table 34-7 ), as well as psychosocial support including vocational guidance and sexual functioning ( Table 34-8 ).
| Area of Interest, with Treatment Goals ∗ | Evaluation/Assessment | Intervention | Expected Outcomes |
|---|---|---|---|
Physical activity counseling
| Assess current physical activity level and determine domestic, occupational, and recreational needs. Assess readiness to change behavior, self-confidence, and barriers. | Recommend gradual increases in daily lifestyle activities over time, and how to incorporate it into daily routine and evenly spread throughout the week, i.e., minimum 5 days a week. Emphasize sedentary lifestyle as risk factor and the benefits of physical activity: Any increase in activity has a positive health benefit. Advise : Individualize physical activity according to patient’s age, past habits, comorbid conditions, preferences, and goals. Reassure regarding the safety of the recommended protocol. Encourage involvement in leisure activities that are enjoyable. Forewarn : Inform patients on the risk of relapses; education should underline how benefits may be achieved and the need for lifelong continuation. If physical activity interruption has occurred, physical, social, and psychological barriers should be explored, and alternative approaches suggested. | Increased participation physical activities. Improved psychosocial well-being Prevention of disability Improved aerobic fitness and body composition |
Smoking cessation
| Smoking status and use of other tobacco products Amount of smoking (per day) (number of years) Determine readiness to change; if ready, choose a date for quitting. | All smokers should be encouraged professionally to stop smoking all forms of tobacco permanently. Follow-up : Referral to special programs and/or pharmacotherapy (including nicotine replacement) are recommended, as is a stepwise strategy for smoking cessation. Provide structured follow-up. Offer behavioral advice and group or individual counseling. Consider nicotine replacement therapy, combined with bupropion or varenicline if not contraindicated. | Long-term abstinence from smoking |
Nutritional counseling
| Daily caloric intake and dietary content of fat, saturated fat, sodium, and other nutrients Assess eating habits. | Education regarding dietary goals and how to attain them
| Patient understands basic principles of dietary content. Patient adheres to prescribed diet. |
Weight control management
| Measure weight, height, and waist circumference. Calculate BMI. | BMI : It is useful to consistently encourage weight control through an appropriate balance of physical activity, caloric intake, and formal behavioral programs when indicated. Waist circumference : It is beneficial to initiate lifestyle changes and consider treatment strategies for metabolic syndrome as indicated. | To lose 5%-10% of body weight in 6 months. Consider referring patient to specialist obesity clinic if goal not reached. |
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