CARDIAC REHABILITATION - RISKS, SAFETY, AND COST ISSUES
Exercise training involves certain risks, especially in patients with undiagnosed or undertreated myocardial ischemia, ventricular arrhythmias, or LV dysfunction. The intensity of exercise must be kept below the level of exercise at which the abnormalities were elicited during the risk stratification and testing phase.
SELECTION OF PATIENTS
The proper selection of patients is of paramount importance before phase 2 or phase 3 exercise programs are begun. Patients with certain characteristics are at a higher risk and therefore require all attempts at correction of the high-risk condition prior to exercise training.
Patients also must be monitored with continuous electrocardiography and be supervised closely.
High-risk factors include the following:
Severe LV dysfunction, LV ejection fraction (EF) less than 30%, congestive heart failure (CHF), and history of cardiogenic shock
Severe exercise-induced ischemia (such as angina at a workload of less than 5 METs), ST-segment depression of greater than 0.2 mV on an ECG, multiple perfusion defects on exercise nuclear stress testing, or multiple dyskinetic LV segments on stress echocardiography
Complex ventricular arrhythmias, such as non-sustained ventricular tachycardia (a less than 30-second run of ventricular tachycardia [VT]) at rest or with exercise or a history of previous sudden cardiac arrest (SCA)
Hypotensive response to exercise (ie, drop in systolic pressure of more than 20 mm Hg at incremental exertion)
Low functional capacity (ie, peak workload of less than 5 METs, functional capacity determined by CPX testing with reduced peak oxygen [VO2 max] consumption)
Patient's inability to self-monitor his/her heart rate
For some patients, the risks of exercise may outweigh the benefits. In these instances, patients should be counseled against exercise training, and their medical management must first be optimized with thorough supervision.
SURVEILLANCE
High-risk patients, constituting approximately 15-25% of all patients referred for cardiac rehabilitation, require the maximum level of supervision and surveillance, including continual ECG monitoring. The group of high-risk patients described above constitutes the bulk of such patients.
Intermediate-risk patients need somewhat less intense surveillance. The level of supervision needed includes unmonitored exercise training in groups in the presence of health professionals who are certified in advanced cardiac life support (ACLS).
Very low-risk patients can exercise safely and independently once they have learned how to monitor their pulse rates and are able to recognize warning signs. Such patients have greater than 8 METs of exercise capacity without symptoms or signs of angina, heart failure, or arrhythmias.
Alternative approaches to the traditional supervised cardiac rehabilitation programs have been evaluated and found to be reasonably safe.
These off-site, self-monitored or telemetry-monitored programs are applicable primarily to very low-risk patients and include
Ø Home-based cardiac rehabilitation (effective & safe)
Ø Exercise with trans-telephonic surveillance
SAFETY
Supervised exercise training programs have extremely good safety records, despite the inherent potential for cardiovascular complications during exercise.
None of the more than 3 dozen randomized controlled trials of cardiac rehabilitation exercise testing and training in patients with coronary heart disease, involving over 4,500 patients, showed any increase in morbidity or mortality in rehabilitation compared with control patient groups.
A 1980-1984 survey of 142 US cardiac rehabilitation programs reported a low rate of nonfatal myocardial infarction (MI; 1 case per 294,000 patient-hours) and cardiac mortality (1 case per 784,000 patient-hours). A total of 21 episodes of cardiac arrest occurred, with resuscitation successfully performed in 17 of these episodes. Therefore, the safety of exercise within cardiac rehabilitation programs is well accepted and established.
ANALYSIS OF COST-EFFECTIVENESS
Cardiac rehabilitation, a clinically effective intervention for coronary heart disease, has been subjected to preliminary cost analyses. In a US study, a randomized, 8-week trial of rehabilitation beginning 6 weeks following MI showed a cost-effectiveness of $9,200 per quality adjusted life year.
Subsequently, a similar analysis showed a cost-effectiveness of only $4,950 per year of life saved. In contrast, cholesterol lowering for secondary prevention has a cost-effectiveness of $9,630 per year of life saved, thrombolytic therapy for acute MI has a C/E of $32,700 per year of life saved, and bypass surgery has a cost-effectiveness of $18,700 for a year of life saved.
In Sweden, a comprehensive cost analysis of cardiac rehabilitation, performed on patients following MI or bypass surgery (with a 5-year follow-up), showed that re-hospitalizations decreased from 16 to 11 days; the study also showed a higher rate of return to work (53% versus 38%). Overall, cardiac rehabilitation programs resulted in cost savings to the Swedish system of $12,000 per patient.
Research therefore indicates that cardiac rehabilitation is not only clinically effective, but is cost-effective as well. Cardiac rehabilitation compares favorably with other medical interventions performed commonly in patients with coronary heart disease.