CHAPTER 45: REHABILITATION OF THE PATIENT WITH CORONARY HEART DISEASE

Cardiac rehabilitation (CR) represents an important component of cardiovascular (CV) risk reduction and promotion of CV health. A key component of integrated care, CR provides implementation of exercise training, CV risk reduction, specifically in relation to nutrition and weight, diabetes management, lipid management, hypertension control, and stress reduction. The goal of CR services is to stabilize or reverse progression of atherosclerosis, reduce the risk of myocardial infarction (MI) and sudden death, control cardiac symptoms, and enhance the patient’s psychosocial and vocational status.

The beneficial effects of exercise have been investigated for centuries. In 1768, Herbeden observed that a patient with angina improved after chopping wood for 30 minutes a day. This finding is one of the first publications noting the CV benefit of exercise in patients with coronary disease.¹ William Stokes advocated walking for patients with heart disease in the mid-1800s, but this was in contradiction to the popular opinion stressing the importance of bed rest for weeks after a CV event. In the 1950s, Samuel Levine and Bernard Lown noted both physical and psychological benefits of early mobilization following acute coronary symptoms.² Concurrent with gradual changes from sedentary convalescence to early mobilization after acute coronary events, the importance of risk factors and lifestyles in the genesis of coronary disease was realized, and the concept of CR was born. The first structured rehabilitation program was pioneered in Israel in 1955.³

Furthermore, the differentiation between primary and secondary prevention (SP) of coronary heart disease (CHD) was challenged. Pathologic studies confirmed that atherosclerosis may develop insidiously over decades and may be advanced at time of presentation with symptoms or an acute event. Newer diagnostic tests for acute coronary syndromes have shown that MI represents a continuum of damage. The presentation of a person with angina, an acute coronary syndrome, or coincidental asymptomatic disease should now trigger the initiation of a lifelong program of risk factor modification including physical exercise.

In parallel with this philosophy, CR has evolved and is considered a class I indication in most clinical practice guidelines for patients with stable angina, acute MI within the Past 12 months, percutaneous coronary intervention (PCI) with or without stenting, or coronary artery bypass graft (CABG) surgery. In addition, CR is recommended for patients with peripheral arterial disease,⁴ valvular disease,⁵ congestive heart failure,⁶ and heart transplant. Additional candidates for CR include those with pulmonary hypertension and congenital heart disease.⁷

CR has developed worldwide but differs widely among countries, from highly structured inpatient programs to informal home-based programs. Although there may be no ideal rehabilitation program, the majority consist of regular outpatient exercise and educational programs. Comprehensive rehabilitation involves a multidisciplinary team comprising a physician, program manager, CV nurse, exercise physiologist or physical therapist, and access to a registered dietician and clinical psychologist.

This chapter, in addition to defining the essential components of CR programs, will provide an update on recently published studies that will impact the future of CR and health promotion programs. Specific studies address survival benefit, utilization of services, and alternative delivery strategies.

CR and SP programs are now accepted as an integral component of the comprehensive care of patients with CV disease. Typically, CR comprises exercise and educational programs with the aim to promote the uptake and maintenance of appropriate physical activity and healthier lifestyle changes, so as to positively influence the individual’s recovery and as a means of SP. Since the 1980s, a variety of working groups and committees have published guidelines and recommendations for CR.^{8,9,10,11,12,13}

In 1995, the US Department of Health and Human Services, Public Health Service, Agency for Health Care Policy and Research issued guidelines⁸ that are still widely used, describing CR as a comprehensive long-term program involving medical evaluation, prescribed exercise, cardiac risk factor modification, education, and counseling, designed to limit the physiologic and psychological effect of cardiac illness, reduce the risk of sudden death or reinfarction, control cardiac symptoms, and enhance the psychological and vocational status of the individual patient.

Early in the 21st century, the European Society of Cardiology¹⁰ published guidelines regarding evaluation and intervention in all aspects of CR. These initiatives were aimed at assisting CR staff with the development of CR programs in Europe. Physical activity is also strongly emphasized in the current European guidelines on CV disease prevention.¹⁴

The most recent advisory from the American Heart Association (AHA) makes a compelling argument for the importance of CR and SP programs: “Given the significant benefits that CR/SP programs bring CV disease prevention, every recent major evidence-based guideline from the AHA and the American College of Cardiology (ACC) about the management and prevention of CHD provides a Class 1 level recommendation for referral for those patients with acute coronary syndrome or MI, chronic stable angina, heart failure or after coronary artery bypass surgery or PCI; CR is also indicated for those patients after valve surgery or cardiac transplantation.”¹⁵ The Centers for Medicare and Medicaid Services (CMS) have mandated that CR services be individualized to provide optimal efficient care. In this era of patient-centered medical homes and accountable care organizations, CR/SP programs should be positioned to improve CV disease outcomes by providing important services to high-risk populations.

Mortality and Cardiovascular Outcomes

During the past 20 years, clinical trials and meta-analyses have reported the following CV benefits for patients enrolled in exercise training programs: reduced mortality at up to 5 years, decrease in CV events, improvement in modifiable CV risk factors, improvement in adherence to preventive medications, improvement in exercise capacity, and improvement in quality of life.^16,17,18 Evidence for the benefit of CR spans many subsets of patients with CHD. Studies of patients with stable CHD or those who have undergone revascularization with PCI provide evidence for reduction in all-cause mortality compared to control groups receiving usual care.¹⁹

The most recent and comprehensive meta-analysis of 63 trials of patients after either MI or revascularization was published in 2016 and confirmed that exercise-based CR reduces CV mortality and hospital admissions and improves quality of life consistently across patient types. This evaluation included 14,486 participants after MI or revascularization followed for 12 months.¹⁷ Results included the following:

• A lower risk of CV mortality (relative risk [RR], 0.74; 95% confidence interval [CI], 0.64-0.86)

• A lower risk of hospital admission (RR, 0.82; 95% CI, 0.70-0.96).

• No significant effect on rates of all-cause death, MI, or revascularization

Patients who have undergone CABG surgery were evaluated in a community-based analysis of 846 patients. Those who participated in a CR program (compared to those who did not) had reduced all-cause mortality at 10 years (23.0% vs 35.7%; adjusted hazard ratio [HR], 0.54; 95% CI, 0.40-0.74).²⁰

Dose Response

The relationship between the number of CR sessions completed in older patients found a dose-dependent reduction in mortality and recurrent MI. Of 30,161 Medicare patients, those who attended 36 sessions had a 14% lower risk of death (HR, 0.86; 95% CI, 0.77-0.97) than those who attended 24 sessions over a period of 5 years.²¹ Improvements in functional capacity and quality of life may translate to increased probability of returning to work or to maintenance of independent living in older patients. The relationship between completion of CR and mortality was also noted in a prospective cohort study of 5886 patients (70% with an acute coronary syndrome) referred for CR. Those who attended 36 sessions had a reduced rate of hospitalizations and a 22% lower risk of death than those who completed 12 sessions (HR, 0.78; 95% CI, 0.71-0.87).²²

Taken collectively, these studies suggest that reported mortality reductions associated with exercise-based rehabilitation may apply to both patients with acute coronary syndromes and those who have undergone revascularization. Psychological benefits, improved coronary blood flow and functional capacity, and reductions in risk factors and inducible ischemia have also been reported.^2,9,17

Physiologic Benefits

Exercise has been shown to improve CV risk factors, including blood pressure, lipid profile, weight, smoking, and prevention and treatment of diabetes mellitus.^16,23 Following MI, exercise training results in lower blood pressure and heart rate for a given level of exertion and may improve aerobic capacity. Resistance training in combination with aerobic training has been shown to improve both endurance and skeletal muscle strength.

Exercise is associated with positive atherogenic and anti-inflammatory effects. In addition, studies have shown improved endothelial function and a more favorable fibrinolytic balance.²⁴ Specific biologic mechanisms for the benefit of exercise are summarized in Table 45–1.

Heart Rate Recovery

Heart rate recovery is an indicator of CV health, and impaired heart rate recovery predicts mortality. In a study of 544 patients with abnormal heart rate recovery prior to starting CR, the exercise program resulted in a 41% improvement in heart rate recovery. Importantly, those who had evidence of poor heart rate recovery at the completion of CR had a higher likelihood of all-cause death.²⁵

Left Ventricular Remodeling

Following MI, exercise training has proven benefits on left ventricular (LV) function and remodeling. The most recent evaluation of this topic is a 2011 systemic review. In clinically stable patients after MI, exercise training had a positive effect on LV remodeling.²⁶ The effects were greatest when exercise training started 1 week after MI and lasted longer than 12 weeks.²⁶

Psychological Benefit

Depression is associated with fatigue, reduced exercise capacity, and reduced quality of life. The association between depression and CHD is well known, with an estimated 20% to 45% of patients demonstrating significant depression after MI.²⁷ In addition, anxiety is associated with a worse prognosis in patients with CHD.²⁸ CR programs assess psychological stress and depression at intake and provide access to group and individual counseling sessions. In a 40-month study of 500 consecutive CHD patients, improved fitness was associated with decreased depressive symptoms and decreased mortality. Patients with depression demonstrated a fourfold increase in mortality compared with nondepressed patients (22% vs 5%).²⁹

The indications and contraindications for CR are summarized in Table 45–2. To establish a safe and effective program of comprehensive CV disease risk reduction and rehabilitation, each patient should undergo a careful medical evaluation and exercise test before participating in an outpatient CR/SP program. The specific components of the medical evaluation should include a medical history, physical examination, and resting electrocardiogram (ECG). The exercise test should be repeated any time that symptoms or clinical changes warrant, as well as in the follow-up assessment of the exercise training outcome³⁰ (Table 45–3).

Phases

Worldwide, CR is structured in different ways. The term phase is used to describe the varying time frames following a cardiac event. There are four phases of CR in both Europe and the United States (Table 45–4), but variations in the structure of these phases exist.

Phase I

Inpatient

Phase I traditionally begins in the hospital. The patient is reviewed by the nutritionist, social worker, and physical therapist. Individual risk factors are discussed, and the patient is first introduced to the concept of lifelong lifestyle changes. Simple breathing and leg exercises are commenced with a program of gradual mobilization. The emphasis at this stage is to counteract the negative effects of deconditioning after a cardiac event. A patient is considered appropriate for daily ambulation/mobilization if (1) there has been no new or recurrent chest pain during the previous 8 hours; (2) neither troponin nor creatine phosphokinase (CPK) is increasing; (3) there are no signs of decompensated heart failure; and (4) there is no significant change in ECG or rhythm in previous 8 hours.³¹ A discharge plan is formulated taking into account individual needs (eg, return to work, medications, exercise program).

After Discharge

The length of time between discharge and commencement of the phase II program varies between countries and facilities. The usual mode of exercise prescribed initially is walking on level ground. The intensity should be maintained between 2 and 4 metabolic equivalents (METs) or a score of 11 to 12 on the Rating of Perceived Exertion (RPE) Scale in the early stages.³⁰ Patients should be told to increase their walking distance progressively to 3 to 5 km daily after 4 to 6 weeks.

Phase II (Outpatient Exercise Program)

The aim of this phase of the CR program is to enable the patient to exercise safely in a structured environment and to understand the benefits of exercise. Prior to commencing an exercise program, it is usual for a patient to undergo a symptom-limited exercise stress test. Exercise testing can be used as either a diagnostic or prognostic tool or as a test of functional capacity. It is mainly for the latter reason that exercise testing is recommended in CR. This information aids assessment for exercise prescription and return to work evaluation and helps in an estimation of prognosis. The absence of a test may lead to an inappropriate exercise prescription.³⁰ Absolute and relative contraindications to exercise testing are shown in Table 45–5.

Recommended intensities for the structured exercise in phase II (outpatient phase) vary depending on the technique used to prescribe exercise intensity. Cardiac patients should exercise in the low to moderate range of exercise intensity, corresponding to 60% to 75% of maximum heart rate (HR_max)¹³ or 60% to 70% of maximum heart rate reserve,³⁰ corresponding to a score of 12 to 14 on the RPE Scale.¹³ Although most accurately measured using a cardiac stress test, the most common way of calculating the HR_max is to subtract the patient’s age from 220. The heart rate reserve is calculated by subtracting the resting heart rate from the HR_max.

The types of exercises used during the exercise program should promote total physical conditioning, including treadmills, cycle and arm ergometers, stair climbers, and rowing machines.³¹ These exercises are mainly aerobic in nature, but resistance training can be used in lower to moderate risk cardiac patients. However, it is recommended that patients spend some time on aerobic-type exercises first before progressing to resistance exercise. The type and quantity of equipment available will depend on the resources available, the available space, and the number of patients in the group. It is usual for 8 to 10 patients of similar functional capacities to exercise together, but this number will vary depending on the patients’ functional limitations and the availability of staff. A warm-up period of approximately 15 minutes is followed by the exercise session, which lasts for 30 to 35 minutes; the exercise session is followed by a cool-down period of 10 minutes.

Phase III

During phase III, the patient may continue to exercise in the same CR facility, without telemetry monitoring, but with the supervision of an exercise physiologist or physical therapist. Most phase III programs are available 2 to 3 days a week, while promoting independent exercise and lifelong lifestyle modifications.

Phase IV

Phase IV is a maintenance program often in the form of a gym or health club facility membership, ideally with occasional sessions to help sustain lifestyle change.

Target Population

Traditionally, for patients with CHD, CR is offered to patients after uncomplicated MI or after successful revascularization with coronary artery bypass surgery or PCI.³² In addition, higher risk subjects, such as elderly patients with comorbidities, patients with automatic internal cardiac defibrillators, and patients before and after cardiac transplantation, often participate in tailored CR programs.

The exercise goals of a CR program are developed based on the individual’s baseline ability and limitations. An exercise prescription is developed and is composed of the mode, frequency, duration, and intensity of exercise.²⁴ Risk stratification is performed with each patient prior to initiation of exercise program. The guidelines published by the AHA use the following four categories according to clinical characteristics. Most patients who are referred to CR programs are class B or C, where supervised exercise is associated with a small risk of adverse events.²⁴

1. Class A individuals are apparently health without increased CV risk with exercise.

2. Class B individuals have clinical stable CHD and are at low risk of CV complications with vigorous exercise (Table 45–6).

3. Class C individuals are at moderate or high risk of cardiac complications during exercise due to one of the following: history of multiple MIs or cardiac arrest; New York Heart Association class III or IV angina, exercise capacity of less than 6 METs, and significant ischemia on exercise stress test (Table 45–7).

4. Class D individuals are those with unstable disease who require restriction of activity and for whom exercise is contraindicated.

The way in which CR is delivered may differ nationally and internationally, but certain standard core components, including baseline patient assessment, psychosocial interventions, nutritional counseling, risk factor management (lipids, blood pressure, weight, diabetes mellitus, and smoking), physical activity counseling, and exercise training, have been adopted by Europe and the United States.¹²

Exercise Training

Exercise Stress Testing

The exercise stress test, using a standard graded increase in demand, assesses exercise capacity while monitoring symptomatic and hemodynamic responses. The World Health Organization expert committee on CR states that the primary purpose of an exercise test is to determine the responses of the individual to efforts at given levels and, from this information, to estimate probable performance in specific life and occupational situations.³¹ Indications for exercise stress testing include diagnostic, prognostic, and therapeutic applications. In CR, the exercise test is used to determine the target heart rate for exercise prescription.³³ Exercise stress testing in CR is performed to measure the ischemic threshold, assess for arrhythmias, assess exercise tolerance, evaluate hemodynamic response (blood pressure, heart rate), and observe for signs and symptoms of ischemia. Table 45–5 outlines the contraindications to stress testing.

Various protocols are available for exercise testing, and the choice should depend on the outcome and the clinical characteristics of the patient. The Bruce protocol is perhaps one of the most common protocols that is used, although the increments between each stage are quite large; thus for older or deconditioned patients, protocols such as the Naughton protocol may be more appropriate.³¹ The test is traditionally carried out using a treadmill or a cycle ergometer (for those with orthopedic issues) with monitoring of ECG, heart rate, and blood pressure. The RPE Scale and the individual’s description of his or her levels of angina and dyspnea are also assessed. The exercise test usually lasts for 8 to 12 minutes and is terminated when the patient develops symptoms or when he or she achieves a physiologic end point, such as 85% of maximal predicted heart rate. Other absolute and relative indications for terminating the test are given in Table 45–8.

The subject’s general appearance during the exercise test is also of value and should be carefully observed during the exercise test. Signs of poor perfusion, such as cyanosis or pallor, and increasing nervous system symptoms, such as ataxia, dizziness, and vertigo, serve as absolute test termination criteria. Although the diagnostic value has not been confirmed, cardiac auscultation immediately after exercise has been proposed to assess cardiac function. The development of a mitral regurgitant murmur, fourth heart sound, or a palpable precordial bulge after exercise could suggest LV dysfunction resulting from exercise.²⁴

Exercise Capacity

Aerobic exercise capacity is one of the best predictors of risk for future adverse events in apparently healthy individuals, those at increased risk for CV disease, and virtually all patient populations, independent of other traditional risk factors. One MET is defined as 3.5 mL O₂ uptake/kg/min, or the resting oxygen uptake in a sitting position. A meta-analysis including 33 studies reported that a 1-MET increase in aerobic capacity resulted in a 13% and 15% decrease in rates of all-cause death and CV events, respectively.³⁴ In estimating exercise capacity, the amount of work performed in METs (or exercise stage achieved) is preferred to the number of minutes of exercise due to variations in protocols. Aerobic capacity should be reported as both the actual value achieved and a percent-predicted value.²⁴

Exercise Program

Entry into a CR program begins 1 to 3 weeks after discharge from the hospital after MI or PCI, depending on the clinical status of the patient. Patients who have undergone cardiac surgery should delay upper extremity training for 4 to 6 weeks. Sessions are scheduled for either 2 or 3 days per week and last for 9 to 36 weeks (average, 12 weeks) depending on patient’s achievement in significant improvement in functional status. Each session includes warm-up and flexibility exercises, which gradually increase heart rate into target range. Aerobic activity using a treadmill, stationary bike, or stepper is recommended for 20 to 30 minutes, followed by a cool down for 5 to 10 minutes involving low-intensity exercise to allow gradual recovery. ECG monitoring continues 6 to 8 minutes after exercise or if blood pressure, heart rate, and ST segments have not returned to normal.²⁴

Intensity

The intensity for exercise training can be calculated from the exercise test, and for cardiac patients, the heart rate is the most common method used. There are three methods of using the heart rate, and these include the direct method, the percentage of HR_max, and the heart rate reserve.²⁴ In the direct method, the heart rate is plotted against oxygen consumption, and the appropriate exercise intensity is extrapolated (Fig. 45–1). The percentage of HR_max method uses 65% to 75% of the heart rate achieved during the exercise test, which approximates to 40% to 60% of an individual’s maximal oxygen consumption (VO₂ max). In the heart rate reserve method, the resting heart rate is subtracted from the maximal heart rate (estimated as 220 minus the age in years) to give the heart rate reserve. If an exercise prescription of 60% to 80% of maximal oxygen consumption is required, then 60% and 80% values of the heart rate reserve are calculated, and the resting heart rate is added to each value to give the training heart rate values.²⁴

Patients are taught to measure intensity of exertion by heart rate and RPE Scale (or Borg scale; Table 45–9). Using this scale, an RPE of 12 to 13 (somewhat hard) corresponds to 60% VO₂ max, and an RPE of 16 (hard to very hard) corresponds to 85% VO₂ max. Low-risk patients (class B) may use low-level resistance training to increase muscle strength and endurance.²⁴

Safety of Cardiac Rehabilitation

The risk of a cardiac event in patients diagnosed with CHD is increased when there is extensive damage to the myocardium, residual ischemia, and ventricular arrhythmias.³⁰ The AHA Scientific Statement on exercise and acute CV events noted that the risk of any major CV complication is one event in 60,000 to 80,000 hours of supervised exercise.³³ The observation that the incidence of cardiac arrest is six-fold higher than the death rate indicates the value of successful resuscitation during supervised CR but also suggests that the death rate likely would be higher during unsupervised exercise. Staff supervising such exercise programs must be appropriately trained in advanced cardiac life support with ECG monitoring available for patients deemed high risk.³¹

Recommendations on prevention and rehabilitation acknowledge that patient management should be based on an assessment of total risk. The various components addressed by CR programs will generally include attention to the following aspects:

• Behavior change

• Smoking

• Weight management

• Nutrition

• Lipids

• Blood pressure

• Psychosocial factors

• Cardiopulmonary resuscitation training

Behavior Change

A primary principle of patient education is to facilitate necessary behavior change known to improve health outcomes. Changing health behavior requires assessment of a patients’ knowledge, attitudes, and beliefs as well as psychological health (especially anxiety and depression). The American Association of Cardiovascular and Pulmonary Rehabilitation acknowledges several guiding principles in effecting necessary change, as listed in Table 45–10. Support from the physician, program staff, and family contributes to the effective behavioral change. CR programs offer the opportunity for comprehensive, evidence-based, lifestyle modification.³⁰

Smoking

Cigarette smoking, a major risk factor for the development of CHD, remains a leading cause of preventable death worldwide.³⁵ It is expected that the number of smokers worldwide will increase to > 1.6 billion by 2025.³⁶ The causal relationship between smoking and CV disease is well established. The effects of smoking on the CV system include stimulation of smooth muscle proliferation and cell migration to intima, increase in platelet adhesion to the endothelium, and an increase in fibrinogen levels (increased clotting).² Smoking cessation will reduce the subsequent risk of death by up to 9% in absolute terms.³⁶ Observational studies in post-MI patients suggest that this may be reflected as a halving of long-term mortality.³⁷

CR programs are the ideal setting in which to promote smoking cessation. Educating patients about the association between smoking and heart disease at this vulnerable period may be the trigger to motivate smoking cessation. Numerous nonpharmacologic and pharmacologic agents are available to aid the patient and health professional with this campaign. Both group therapy and individual counseling to instigate behavioral change are useful in helping the patient to quit smoking. Nicotine replacement therapy in the form of transdermal patches, chewing gum, nasal spray, oral inhalers, and sublingual tablets may augment the process of smoking cessation.²

Weight Management

Obesity is a major public health problem throughout the developed world. Overweight, obesity, and excess abdominal fat are related to important CHD risk factors, including high levels of total cholesterol, low-density lipoprotein cholesterol, triglycerides, blood pressure, fibrinogen, and insulin and low levels of high-density lipoprotein cholesterol.³⁸

For overweight and obese patients with CHD, the combination of a reduced-energy diet and increased physical activity is recommended. An energy deficit is most readily achievable through choice of foods low in total fat content, with a reduction in saturated fat being more preferable. Further reductions in total energy intake can be achieved by reducing refined carbohydrate intake.²

Nutrition and Lipids

Nutrition plays a pivotal role in the etiology and development of CV disease. A range of dietary measures can make a favorable contribution to the secondary prevention of coronary artery disease.³⁰ Changes in the quantity and quality of dietary fat improve the lipid profile. Blood pressure is lowered by reducing sodium intake and by adhering to the Dietary Approaches to Stop Hypertension (DASH) diet, a diet rich in vegetables, fruits, and low-fat dairy products and low in saturated and total fat. Consumption of a diet relatively low in fat, trans-fatty acids, saturated fatty acids, cholesterol, and sodium or relatively high in fruit, vegetables, polyunsaturated fatty acids, monounsaturated fatty acids, fish, fiber, and potassium is likely to reduce the risk of CV disease.^39,40,41 Dietary therapy is additive to drug therapy and further reduces CV risk. Failure to adopt a cardioprotective diet may result in the need to use higher doses or combinations of medications.^42,43 A cardioprotective diet pattern has been developed for easy incorporation into CR programs. The cumulative advantage accruing from all food and nutrients in an integrated dietary pattern offers the prospect of a substantial reduction in risk of CV disease for individuals and populations.⁴⁴

This dietary pattern (which is based on the Mediterranean diet) may be summarized as follows:

• Low in saturated fatty acids

• Low in trans-fatty acids

• Replace saturated fats with monounsaturated and polyunsaturated fats

• Omega-3 fatty acids (eg, oily fish)

• Replace some fat intake with soluble fiber

• Reduce salt

• Five or more portions of fruit and vegetables daily

There is insufficient evidence to recommend nutrition supplements of antioxidant vitamins, minerals, or trace elements for the treatment of CV disease. There is evidence to support the effectiveness of nutritional education in generating positive and long-lasting changes in the dietary habits of patients involved in CR.⁴⁵ Therefore, nutritional evaluation, counseling, and monitoring must occur as part of a comprehensive CR program.

CR nutrition education is conducted over four phases to facilitate patient learning. Some patients may require more information/nutrition counseling than they can obtain in the context of a group program, such as patients with additional health needs (eg, diabetes mellitus, obesity, chronic heart failure) and patients from culturally and linguistically diverse backgrounds.² A structure for nutritional education sessions is available in Appendix 45–1.

Hypertension

Evidence exists regarding the importance of hypertension as a risk factor for CV disease and the importance of lifestyle measures and appropriate medication to treat and control hypertension.¹⁴ (See Chap. 25 for medical therapy of hypertension.)

Management of Hypertension

It is well recognized that hypertensive vascular disease is a continuum. Genetic, environmental, and coexisting risk factors influence the rapidity and progression of vascular changes within the blood vessel walls. Ambulatory blood pressure monitoring is recommended to confirm diagnosis.⁴⁶ Change in lifestyle behaviors may have important effects on BP control. Excessive alcohol consumption is associated with hypertension, and reduction or cessation of consumption of alcohol has been shown to improve blood pressure and reduce need for medication.⁴⁶ A majority of people with hypertension are salt-sensitive, and reductions in dietary salt are effective. There is a direct link between increasing body weight and blood pressure levels, particularly if fat distribution is central.³⁸ Obesity contributes to hypertension through its effect on the sympathetic and renin-angiotensin-aldosterone systems. Stress has a major effect on blood pressure, and recognition and elimination of this factor may have important effects. A weight loss of 5 kg has been shown to correspond to a blood pressure reduction of 10/5 mm Hg. Secondary causes of hypertension may be diagnosed if one of the following is noted: blood pressure of ≥ 180/110 mm Hg, uncontrolled hypertension despite three medications, or nondipping of blood pressure during 24-hour ambulatory blood pressure monitoring.

Lifestyle changes and patient education are paramount in the management of hypertension. Such lifestyle measures include smoking cessation, regular exercise, weight reduction, and dietary changes. These measures will also enhance the effects of antihypertensive medication and demonstrate favorable influence on overall CV risk. The recommended DASH diet (low in salt and saturated fat and high in fiber, fruit, and vegetables) can lower blood pressure as effectively as nondietary measures using maximum monotherapy.⁴⁷ Effective implementation of nonpharmacologic measures requires knowledge, time, and resources best undertaken by well-trained health professionals. CR provides an ideal setting to improve CV risk factors.

Psychosocial Factors

Psychosocial factors may impact on the occurrence and recurrence of CHD and may affect rehabilitation. Psychosocial factors are numerous and include anxiety and/or depression, personality issues (eg, hostility, cynicism, mistrust), social isolation, anger and hostility, type D (or distressed) personality, lack of social support, chronic or subacute life stress (eg, stress at work, high demands, limited decision making, low rewards), or accumulation of painful and difficult situations during a relatively short period of time.² Psychological stress can be as dangerous to the heart as physical stress for people with coronary artery disease. The link between depression, social isolation, and lack of quality social support and heart disease is strong and consistent. Depression, social isolation, and lack of quality social support are as risky to heart health as abnormal levels of blood fats, smoking, and high blood pressure. Prospective cohort studies provide strong evidence that psychosocial factors, particularly depression and social support, are independent etiologic and prognostic factors for CHD.²

Pathophysiologic mechanisms with acute stress and intense emotion lead to sympathetic nervous system stimulation with an increase in heart rate and blood pressure, vasoconstriction, proarrhythmic potential, reduced endothelial dysfunction, endothelial injury, platelet activation, and/or hemostatic changes, all of which can result in the clinical consequences of myocardial ischemia, arrhythmias, and the potential for thrombosis. Positive psychological effects of CR have been demonstrated, although the variety of instruments used to assess health-related quality of life makes quantitative analysis difficult.⁴⁸

Anxiety and depression are prevalent in both cardiac patients and their families, and are associated with increased morbidity and mortality. Although they may be normal responses after a cardiac event and a natural part of recovery after any life-threatening or stressful event, in excess, they may seriously impede rehabilitation. Anxiety can affect both short- and long-term recovery after a cardiac event. It may relate more to how an individual responds to his or her condition than to its severity. Anxiety may trigger a variety of physiologic responses, such as increased levels of circulating lipids, platelet and macrophage cell activation, and increased heart rate, blood pressure, and myocardial oxygen demand, all of which have the potential to contribute to atherosclerosis and acute coronary syndromes. These responses have implications for the development of atherosclerosis, ischemia, MI, and sudden death.²

CR programs provide a valuable chance to assess cardiac patients for anxiety and depression and provide interventions for those who need specialized care. Many instruments are available to CR professionals to assess anxiety and depression. The most practical method is the use of a self-report scale. Within psychology, psychometric robustness (which includes reliability and validity), sensitivity to change over time, brevity (which minimizes demands on patients), and a track record of having been used in past well-designed studies are some of the important hallmarks of good self-report measures for use in assessment, intervention, and evaluation studies with patients with chronic illness.⁴⁹ A commentary on these instruments is included in Appendix 45–2. There is evidence that the use of active coping, rather than avoidant coping strategies, may lead to positive psychological adjustment and improved quality of life. The principles of self-management programs are outlined in Appendix 45–3.

Cardiopulmonary Resuscitation Training for Relatives of Cardiac Patients

Sudden cardiac death is defined as follows: “An unexpected death due to cardiac causes that occurs within one hour of symptom onset. Cardiac arrest, usually due to cardiac arrhythmias, is the term used to describe the sudden collapse, loss of consciousness and loss of effective circulation that precedes biologic death.”⁵⁰

Recognition and treatment of potentially lethal arrhythmias in the coronary care unit has reduced mortality; however, up to 75% of fatalities occur out of hospital. Of these out-of-hospital cardiac arrests, it is estimated that a majority occur in the home with the spouse or family member being a witness.⁵¹

An important need identified by spouses of recovering cardiac patients is the need to learn what to do if their spouse has a cardiac arrest at home.⁵² Various professional associations have made recommendations regarding cardiopulmonary resuscitation (CPR) training for the relatives of cardiac patients. The AHA endorsed CPR training of the lay public in 1971, and from 1992, the AHA guidelines recommend targeting courses to relatives and close friends of persons at risk. The AHA International Guidelines starting in 2000 strongly recommend targeting family members of high-risk adult and pediatric patients, stating that: “Healthcare professionals should recommend CPR training for family members as part of the discharge teaching plan for high-risk patients. Persons caring for high-risk populations must be educated to recognize airway or CV emergencies and must be taught how to intervene appropriately and to contact the emergency medical system.”⁵³

Barriers to Utilization of Traditional Cardiac Rehabilitation Programs and the Future

The most common barrier to CR is lack of physician referral. Despite national guidelines in the United States designating CR as a Class IA recommendation, Menezes et al⁵⁴ report that up to 80% are not referred. In particular, women, those of lower socioeconomic status, and patients aged > 65 years have lower rates of referral.^11,55,56 Additionally, patients who have limitations due to geographic location or insurance coverage issues are less likely to be referred and to participate.¹⁵ Of those who are referred, patient factors for nonparticipation include financial burden, transportation difficulties, and competing priorities.^15,54,57 Importantly, once referred to CR, reasons for nonattendance were more likely due to personal factors, such as perceptions of heart disease and family influence, versus physical issues.⁵⁸ In Europe, the EuroAspire survey analyzed records and interviews of 9000 patients in 22 countries in Europe and reported that only one-third of patients with CHD received any form of CR.⁵⁹ Even among those referred to CR, the dropout rate is high among post-MI patients (29% dropout at 1 month).⁶⁰ Patient-related factors include affordability, including insurance coverage, transportation difficulties, and competing priorities. From a systems perspective, lack of personnel and resources have been cited as having a significant impact on utilization.

Global Issues

CR is a Class 1 recommendation from the AHA, the ACC, and the European Society of Cardiology.^61,62 In European CR programs, patients who are referred are more likely to enroll and complete CR due to both national health insurance coverage and employer support.⁶³ Although most of the literature regarding CR originates from higher income countries, CR has been evaluated in low- and middle-income countries (LMICs) and has demonstrated improved clinical results, but lower enrollment rates.⁶⁴ Worldwide, only 39% of countries offer CR, with a breakdown of 68% of high-income countries versus 23% of LMICs.⁶⁵ Although fewer randomized trials of SP programs have been undertaken in LMICs, improvement in clinical outcomes should be expected with CR programs, given the particularly poor rates of control of CV disease risk factors. Due to both financial constraints and geographic challenges, the use of home- or community-based programs warrants investigation in LMICs. Strategies to improve CR availability are necessary and include supportive public health policies as well as novel models of delivery.⁶⁵

Delivery Systems

In light of the known barriers to care, innovative strategies to bring CR to more patients necessitates newer delivery models. In addition to telemedicine models, Internet-based, home-based, and community-based programs may complement the current facility-based programs.⁶⁶ A systematic review and meta-analysis of home-based versus facility-based CR concluded that for low-risk patients after MI and revascularization, home-based CR improved health-related quality of life and clinical outcomes including death, revascularization, or hospital admission equally as well as center-based CR.⁶⁷ The out-of-facility delivery models should augment the various needs of individuals based on their individual CV risk, age, and social support. Recently, investigators from Toronto, Canada, compared health behaviors and outcomes of women randomly assigned to women-only CR programs with women assigned to participation in traditional programs and found both physical activity and quality of life improved in both groups.⁶⁸ Other alternatives for providing comprehensive CV risk reduction include electronic media programs.⁶⁹ Mobile health technologies such as the Circle of Health app provide education, motivation, and instruction for all individuals interested in maintaining CV health.⁷⁰ Mobile technologies may be used in connection with at-home or facility-based programs with the potential to improve outcomes.

CR programs provide comprehensive risk factor assessment and treatment and reduce morbidity and mortality in patients with chronic CV disease. Despite powerful evidence of clinical benefit, quality of life improvement, and cost-effectiveness, reimbursement for most services remains low. Although mortality from CV diseases is on the decline, there has been a dramatic increase in clinical conditions, such as obesity, diabetes mellitus, and the metabolic syndrome, that will lead to increases in CV morbidity. In addition, as the world’s population ages, CR will need to be provided to a growing number of elderly patients, many of whom will have a variety of comorbidities.

Although traditional CR focuses on SP, the future scope of CR should encompass aspects of primary prevention and promotion of wellness by providing intensive lifestyle management for physical, medical, and psychological support and education. Preventing these chronic conditions from developing into acute and chronic CV disease is vital. The nature of current CR is changing. Lower risk patients may be able to benefit from CR in community settings, and increasing numbers of higher risk patients with increasing complex medical conditions will require supervised, monitored CR. Both low- and high-risk patients, as well as at-risk patients, may benefit from mobile health technologies and novel hybrid delivery systems of care. As medical interventions and medications continue to lead to successful physical outcomes for cardiac patients, it will be necessary to continue to evaluate the efficacy of CR in terms of behavior change and health-related quality of life.

Thanks to the authors of prior edition: Ian M. Graham, Noeleen Fallon, Shirley Ingram, ToraLeong, John Gormley, Veronica O’Doherty, Vincent Maher, and Suzanne E. Benson. Acknowledgment to Dr. Cynara Maceda and Mr. Connor Haney for their assistance