The Case for Cardiac Rehabilitation After Coronary Revascularization

The objectives of contemporary cardiac rehabilitation are to increase functional capacity, decrease symptoms, reduce disability, improve quality of life, and modify coronary risk factors in an effort to promote plaque stability and/or regression to reduce morbidity and mortality. 1 The most compelling evidence to support these goals comes from studies in postmyocardial infarction patients who have undergone structured, exercise-based rehabilitation programs. 2 Meta-analyses of randomized, controlled clinical trials conducted in the early 1980s on predominantly male survivors of acute myocardial infarction showed that cardiac rehabilitation decreased cardiovascular related and all-cause mortality by 20% to 24% (Figure 1), 3–5 especially as a component of multifactorial rehabilitation (ie, 26% reduction in mortality versus 15% in exercise-only trials), 2 with no difference in the rate of nonfatal recurrent cardiac events. Yet, the generalizability of these widely promulgated endorsements to patients who have undergone elective coronary revascularization (ie, percutaneous transluminal coronary angioplasty or coronary artery bypass graft [CABG] surgery), although promising, 6 remains unproven. 7 Moreover, contemporary thrombolytic interventions, pharmacotherapies, and revascularization procedures, which markedly decrease early postinfarction mortality, may diminish the short-term impact of adjunctive cardiac rehabilitation programs on survival.Figure 1.: Reduced all-cause mortality in postinfarction patients who participated in exercise-based rehabilitation programs in 3 meta-analyses. Confidence intervals are indicated with the bars in the Odds Ratio column.In a prospective cohort study of 691 subjects (81% male) who had undergone CABG surgery at 14 centers in Washington State, published in this issue of JCR, Goss et al 8 found that participation in postdischarge cardiac rehabilitation did not appear to provide a measurable benefit in “self-reported” health status beyond that achieved from the revascularization procedure alone. Perhaps a more fundamental question is, in our search for favorable outcomes to justify the services that we provide (and their commensurate reimbursement), are we sometimes overzealous and unrealistic in our expectations of cardiac rehabilitation, considering the brevity of varied programs for some patients, the challenge of suboptimal compliance rates, and the myriad of potentially confounding variables (eg, comorbidities, medications, congestive heart failure, lack of social support, depression) that may, independently and collectively, positively or negatively influence our results. Coronary artery bypass surgery may be another example, as it alone can serve as a motivator, at least over the short-term, for substantive lifestyle change, facilitating many of the aforementioned objectives of cardiac rehabilitation. In addition to clinical and demographic data, Goss and associates 8 administered the SF-36 Survey, 9 which includes 8 health status domains, and the Seattle Angina Questionnaire (SAQ), 10 which encompasses 5 domains reflecting symptom-related limitations, and other clinically germane questions at baseline and at 6 and 12 months after CABG surgery. In the 1-year survey, patients were asked whether they had participated in cardiac rehabilitation programs following hospital discharge for CABG surgery, and to “recall” their total number of weeks of participation and any perceived benefits. This enabled the investigators to divide their patient population into 3 groups: 1) patients with ≥ 8 weeks of cardiac rehabilitation; 2) patients with < 8 weeks of cardiac rehabilitation; and, 3) nonparticipants. With few exceptions, participants and non-participants in cardiac rehabilitation had similar baseline characteristics. The vast majority of patients stated that cardiac rehabilitation was beneficial, especially those participating for ≥ 8 weeks. When this subset (n = 132) was compared with those who participated < 8 weeks (n = 107), the former were significantly (P < 0.05) more likely to report cardiac rehabilitation as beneficial, as well as an improved energy level, a more favorable outlook on life, enhanced cardiovascular condition, augmented activity in daily living, and a reduced cholesterol level. On the other hand, unadjusted and adjusted 6- and 12-month scores for the SF-36 and the SAQ generally failed to reveal significant differences between participants and nonparticipants in cardiac rehabilitation. When participation status was defined as those patients who completed ≥ 8 weeks of cardiac rehabilitation, only 2 of 13 health status domains favored the intervention, both related to functional status. There was a trend toward higher SF-36 Physical Functioning, and a statistically significant benefit in SAQ Exertional Capacity. Other studies of rehabilitation after CABG surgery, including two randomized controlled trials 11,12 and two observational investigations, 13,14 have reported either no influence or only a modest benefit. Nevertheless, virtually all of these reports had significant methodologic flaws, limiting their generalizability to contemporary medical practice in the United States. Previous studies have, for the most part, evaluated the global effectiveness of cardiac rehabilitation (ie, on all patients, collectively), which may serve to camouflage or attenuate the impact of these interventions on specific patient subsets. To evaluate this possibility, Goss et al 8 conducted a subanalysis of the “sickest” quartile of patients undergoing CABG surgery, defined by their predicted mortality, who also underwent cardiac rehabilitation (n = 47). Once again, there was no measurable added benefit in this patient subset at 6 and 12 months after surgery. Perhaps differences may have been noted had the investigators defined “sickest” as those patients with the worst (ie, most abnormal) initial scores on the surveys that were used to assess self-reported health status, that is, the SF-36 and SAQ, respectively? Recently, Franklin and associates 15 reported that patients with the worst coronary risk factor profiles at baseline demonstrated the greatest improvements after a contemporary phase II cardiac rehabilitation program, as opposed to those with the lowest ejection fraction or most severe coronary disease. Goss and associates 8 appropriately highlighted the major limitations of their study, including the lack of randomization, making self-selection a threat to the interpretation of the findings and proposed conclusions. In addition, the investigators were unable to verify the validity of the “recall” responses, patient participation in cardiac rehabilitation, the duration of participation, compliance/adherence rates, nor the apportioning of services that were provided among the varied rehabilitation programs (eg, what proportion of time was devoted to exercise, education, counseling, and risk factor modification). The study population was relatively young and healthy, which may have also minimized the benefit of cardiac rehabilitation. Moreover, it is possible that the assessment points chosen (6 and 12 months) may have camouflaged early benefits, which dissipated over time, or that the survey instruments selected were unable to detect subtle health status benefits beyond those of the coronary revascularization procedure itself. Oldridge et al 16 demonstrated that a brief period of cardiac rehabilitation of the type used in this trial resulted in an accelerated recovery in some outcome measures at 8 weeks, but by 12 months the benefits were no longer apparent when compared with patients undergoing conventional care. In summary, brief (< 8 weeks) or “extended” (≥ 8 weeks) formal cardiac rehabilitation provided little apparent prolonged benefit in self-reported health status following CABG surgery beyond that observed in nonparticipants. Nevertheless, the case for cardiac rehabilitation services after CABG surgery, individualized for appropriately selected patients, with adequate compliance over an extended period of time, should not be based primarily on the outcomes underscored in the present study. In contrast, the case should be made on the basis of assisting patients in rapidly returning to a productive and active role in society, as well as promoting plaque stability, facilitating global cardiovascular risk reduction, and enhancing coronary artery endothelial function. 17 Contemporary studies have shown that the latter objectives, if achieved, can result in fewer recurrent cardiac events, and a diminished need for costly and oftentimes repeat coronary revascularization procedures. 18,19 The secondary prevention of cardiovascular disease must be recognized as a lifetime pursuit and not a formal program of 8 to 12 weeks duration with long-lasting residual effects. The patient must develop the mind-set to change deleterious behaviors and lifestyles. One approach that has received wide acceptance is to address the individual’s ability to make these changes based on their emotional and intellectual “readiness to change.”20 Patients should also be counseled to deal with relapses, and to recognize that these behaviors, if infrequent, are not necessarily tantamount to failure. How do we achieve long-term compliance to medical therapies and lifestyle change? Physicians, behavioral scientists, and allied health professionals will play a major role in facilitating this outcome measure. The challenge is yours.