Cardiac rehabilitation (CR), in its infancy, evolved in the 1950s with the advent of "chair treatment" for myocardial infarction (MI). This "treatment," described in 1951 by Levine and Lown,1 involved progressive periods of sitting in an armchair starting 1 day after MI. This was indeed a landmark change in the management of the patient with recent MI and set the stage for the slow but definite evolution of CR as we see it today. Of no surprise in those days, the "rehabilitation-exercise cardiologist" was often described as being "too aggressive," "too dangerous," and even "barbaric."
Nonetheless, in the "roaring seventies," CR became a trade of its own. Published reports2 provided data on organized programs for CR and its growing popularity. The patients involved voiced pleasure and gratitude to CR staff for what they experienced and for the camaraderie and social exchange benefit derived.
In the 1980s, a series of small randomized controlled trials of exercise training (typically starting 3-6 months post-MI) suggested significant benefit after MI. Although these studies were individually underpowered to demonstrate survival advantage, meta-analysis suggested a 24% reduction in cardiovascular disease mortality with exercise-based CR.3
Early rehabilitation programs focused almost exclusively on exercise training. As the discipline matured, patient education, risk factor management, psychological screening/intervention, and dietary, vocational, and smoking cessation counseling were integrated to forge the comprehensive CR programs that we know today. In the past 3 decades, the benefits of comprehensive CR programs have become widely recognized.4 Furthermore, the population deemed appropriate for this intervention continues to expand, incorporating higher risk individuals, including those with left ventricular systolic dysfunction or valvular heart disease and recipients of surgical or percutaneous revascularization. More recently, secondary prevention of cardiovascular events through optimizing proven pharmacologic therapies have been woven into the fabric of contemporary CR programs.
Acute and chronic therapy for coronary artery disease has evolved significantly since early meta-analyses3 have suggested survival benefit from exercise-based CR. More contemporary meta-analyses of randomized controlled trials of exercise-based CR have largely confirmed the findings of the 1980s,5 including one study that added more than 4,000 additional patients published through March 2003.5 In concert with this, based on data from a limited number of trials, significant improvements have been noted in total cholesterol, triglycerides, systolic blood pressure, and self-reported smoking rates.
Of special interest is that a number of studies have investigated the effect of exercise on the progression of atherosclerotic disease. Most of these studies incorporated exercise into a multifaceted intervention, including diet. A significant study reported on the long-term follow-up of one of these carefully controlled trials of diet and exercise in men with stable coronary artery disease.6 The men were randomized to an intensive diet and very intensive exercise intervention or limited diet and exercise advice. Sixty-six patients underwent follow-up angiography after 6 years. The exercise group was encouraged to perform 30 minutes of daily cycle-ergometer exercise at home and attend at least 2 supervised 60-minute group-exercise sessions weekly. The intervention group improved their physical work capacity by 28%, whereas the control group remained unchanged. There was no distinction between the 2 groups in temporal changes in total cholesterol, triglycerides, or body mass index. Analyzing serial quantitative coronary angiograms on a per patient basis, these investigators found significantly less progression (59% vs 74%) and significantly more regression (19% vs 0%) in the intervention group compared with the controls.
Historically, CR has been arbitrarily divided into successive phases, typically starting during hospitalization for an acute event. As clinical care and medical economics have evolved, these traditional phases have lost much of their relevance because contemporary CR emphasizes a continuum of care.
Inpatient CR has assumed an introductory role. It is focused on early mobilization, starting as soon as patients are hemodynamically stable and free of symptoms of ischemia, arrhythmia, or heart failure. As the patient progresses to an electrocardiogram telemetry environment, progressive ambulation is appropriate, initially with assistance and hemodynamic assessment before, during, and after exercise. Providing written information for the patient and family, ensuring stable clinical status with activities of daily living, and referring to an appropriate comprehensive CR program are the current emphases. In addition, ensuring that patients are discharged from the hospital on appropriate medical therapy is an important part of the initial intervention. Patients are usually more adherent with drug therapy when initiated in the inpatient environment.
In outpatient rehabilitation, exercise is individually prescribed and monitored. Currently, this monitoring goes beyond electrocardiogram telemetry and includes surveillance of symptoms, hemodynamics, glycemic response to exercise (in patients with diabetes), weight, tobacco use, emotional status, and adherence to medications, diet, and home exercise. It also includes a review of each individual's pharmacologic and device therapy to ensure adherence with consensus guidelines. This "monitored" phase is an intensive, multidisciplinary intervention focused on educating the individual about the disease, its manifestations, and all aspects of its treatment. The goal is to provide each participant with the tools needed to slow disease progression, maintain optimal functional status, and become an informed and active participant in managing his or her condition.
The maintenance phase follows the more formal outpatient phase and is the first true test of patient adherence. Some patients are concerned by the prospect of continuing exercise in unfamiliar surroundings and elect to continue exercising at a CR facility where they feel safe and are familiar with personnel, protocol, facilities, and clientele. Unfortunately, continuing CR services under such circumstances are generally not reimbursed by third-party payers. Regardless of the venue and the degree of medical surveillance, the goal of the maintenance phase is exercise independence and adherence to exercise prescription, healthy diet, weight management, tobacco abstinence, and medications.
The data herein reported by Gupta et al7 specifically address the outcomes of subjects discharged from a formal CR program. Outcome measures were assessed at baseline, CR completion, and at the end of the year. Of note, only 46% of the subjects returned for the 1-year evaluation. Those who returned were older, less likely to be obese, and had a lower body mass index, better diet score, and higher level of self-reported physical activity. Therefore, this 46% of subjects seemed to have continued a good maintenance program for 1 year, but what happened to effective maintenance in the other 54% of subjects?
When assessing the data in those who returned for the 1-year follow-up(compared with CR initiation),there were improvements in all outcome measures, except body mass index and triglycerides. However, when comparing 1-year follow-up to CR completion, there was a significant worsening in 6-minute walk, diet score, and smoking status, indicating a lack of adherence in the 1 year after CR. Of specific note in the improved outcomes is that the high-density lipoprotein cholesterol improved both from baseline to CR completion and, subsequently, to 1-year follow-up. This is, in part, consistent with other data supporting that high-density lipoprotein cholesterol improvements are seen more often after longer term follow-up in such studies.8
The results in this study by Gupta et al7 reflect clearly the great concerns that we have in CR with regard to adherence. Patient factors, the provider's role, and healthcare system factors must all be addressed.9 There are multiple strategies that have been shown to improve adherence. These include, but are not limited to, behavioral skill training, self-monitoring, telephone/mail contact, nurse-managed interventions, and work site clinics. Other mechanisms, such as signed agreements and contingency contracting, have been used.
Over time, with CR programs and with some improvements in adherence, we have seen improved outcomes. However, the central concern remains as to how we "instill" the motivation in our patients to achieve optimal outcomes in CR and secondary prevention. The answer to this is unknown; however, an important component must be one's "self-care responsibility" for his or her personal health. Such is an absolute necessity as we know the benefits of risk factor modification and control in preventing recurrent events. These preventative strategies can be effective with the individual patient practicing "self-responsibility" and can help curtail and control the enormous societal and financial burden of cardiovascular disease.
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