CARDIAC REHABILITATION

CARDIAC REHABILITATION

Cardiac rehabilitation aims to reverse limitations experienced by patients who have suffered the adverse pathophysiologic and psychological consequences of cardiac events.

Cardiovascular disorders are the leading cause of mortality and morbidity in the industrialized world, accounting for almost 50% of all deaths annually. The survivors constitute an additional reservoir of cardiovascular disease morbidity.

In the United States alone, over 14 million persons suffer from some form of coronary artery disease (CAD) or its complications, including congestive heart failure (CHF), angina, and arrhythmias. Of this number, approximately 1 million survivors of acute myocardial infarction (MI), as well as the more than 300,000 patients who undergo coronary bypass surgery annually, are candidates for cardiac rehabilitation.

Traditionally, cardiac rehabilitation has been provided to somewhat lower-risk patients who could exercise without getting into trouble. However, astonishingly rapid evolution in the management of CAD has now changed the demographics of the patients who can be candidates for rehabilitation training.

Currently, about 400,000 patients who undergo coronary angioplasty each year make up a subgroup that could benefit from cardiac rehabilitation. Furthermore, approximately 4.7 million patients with CHF are also eligible for a slightly modified program of rehabilitation, as are the ever-increasing number of patients who have undergone heart transplantation.

OBJECTIVES

The identification of the patients at risk for a cardiac event's recurrence (ie, risk stratification) is central to formulating an appropriate medical, rehabilitative, and surgical strategy to prevent such a recurrence.

Patients who are at low or moderate risk typically undergo early rehabilitation.

The major goals of a cardiac rehabilitation program are:

Cardiac rehabilitation programs have been consistently shown to improve objective measures of exercise tolerance and psychosocial well being without increasing the risk of significant complications.

UTILIZATION

The Agency for Health Care Policy and Research (AHCPR); the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR), and the National Heart, Lung and Blood Institute (NHLBI) have recognized the wide variation in awareness and understanding of the role of cardiac rehabilitation among physicians, ancillary health care providers, third-party payers, and patients with heart disease.

In the past, it was found that only 11% of patients participated in such programs following an acute coronary event. However, there is evidence that participation has increased. Approximately 38% of US patients and 32% of Canadian patients with acute MI who were involved in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) trial were enrolled in cardiac rehabilitation programs.

OUTCOME MEASURES

Current cardiac care has already reduced early acute coronary mortality so much so that further exercise training, as an "isolated" intervention, may not be able to cause significant reduction in the morbidity and mortality. Nonetheless, exercise training has the potential to act as a catalyst for promoting other aspects of rehabilitation, including risk factor modification through therapeutic lifestyle changes (TLC) and optimization of psychosocial support.

Therefore, the outcome measures of cardiac rehabilitation now include improvement in quality of life (QOL), such as the patient's perception of physical improvement, satisfaction with risk factor alteration, psychosocial adjustments in interpersonal roles, and potential for advancement at work commensurate with the patient's skills (rather than simply return to work).

Similarly, among patients who are elderly, such outcome measures may include the achievement of functional independence, the prevention of premature disability, and a reduction in the need for custodial care.

Despite limited data, older male and female patients in observational studies have shown improvement in their exercise tolerance comparable to that of younger patients participating in equivalent exercise programs. In addition, the safety of exercise within cardiac rehabilitation programs, as studied in over 4,500 patients, is well accepted and established.

Cardiac rehabilitation services are, therefore, an effective and safe intervention. These services are undoubtedly an essential component of the contemporary treatment of patients with multiple presentations of coronary heart disease and heart failure.

DEFINITION OF CARDIAC REHABILITATION

DEFINITION

According to the US Public Health Service (USPHS), a cardiac rehabilitation program is defined as a program that involves the following:

Ø  Medical evaluation

Ø  Prescribed exercise

Ø  Education

Ø  Counseling of patients with cardiac disease

Cardiac rehabilitation has to be comprehensive and, at the same time, individualized. The main goals of a cardiac rehabilitation program should include the following:

v  Short-term goals

o    "Reconditioning" the patient sufficiently enough to allow him/her to resume customary activities

o    Limiting the physiologic and psychological effects of heart disease

o    Decreasing the risk of sudden cardiac arrest or reinfarction

o    Controlling the symptoms of cardiac disease

v  Long-term goals

o    Identification and treatment of risk factors

o    Stabilizing or reversing the atherosclerotic process

o    Enhancing the psychological status of the patients

PHYSIOLOGY OF EXERCISE AND CARDIOVASCULAR BENEFIT

Coronary vasodilatation is mainly driven by the bioavailability of nitric oxide (NO), which is produced by the activities of the endothelially derived enzyme NO synthase and is metabolized by reactive oxygen species. This fine-tuned balance is disturbed in people with CAD. This form of impairment of NO production, along with excessive oxidative stress, results in the loss of endothelial cells via apoptosis.

Further aggravation of endothelial dysfunction ensues, which triggers myocardial ischemia in persons with coronary artery disease (CAD). In healthy individuals, an increased release of NO from the vascular endothelium in response to exercise training results from changes in endothelial NO synthase expression, phosphorylation, and conformation.

By the same token, exercise training has assumed a role in the cardiac rehabilitation of patients with CAD, because it reduces mortality and increases myocardial perfusion. This has been largely attributed to the exercise training – mediated correction of coronary endothelial dysfunction in persons with CAD.

In persons with CAD, regular physical activity leads to a restoration of the balance between NO production by NO synthase and NO inactivation by reactive oxygen species, thereby enhancing the vasodilatory capacity in various vascular beds.

Because endothelial dysfunction has been identified as a predictor of cardiovascular events, the partial reversal of endothelial dysfunction achieved by regular physical exercise appears to be the most likely mechanism behind the exercise training – induced reduction in cardiovascular morbidity and mortality in patients with CAD.

CONCLUSION

Cardiac rehabilitation is an important component of the current multidisciplinary approach to the management of the patients with various presentations of coronary heart disease.

Cardiac rehabilitation involves exercise training, education, counseling regarding risk reduction and lifestyle modification, and, frequently, behavior interventions.

The goals of cardiac rehabilitation services are to improve the physiologic and psychosocial condition of patients. Physiologic benefits include the improvement of exercise capacity and the reduction of risk factors (eg, cessation of smoking and lowering of lipid levels, body weight, blood pressure, blood glucose), with the exercise component provided through rehabilitation possibly reducing the progression of atherosclerosis.

Psychological improvements include the reduction of depression, anxiety, and stress. All of these improvements enable the patient to acquire and maintain functional independence and to return to satisfactory and appropriate activity that benefits the patient and society.