Patrick D. Savage

Peak aerobic capacity predicts prognosis in patients with coronary heart disease

BACKGROUND It is unknown if contemporary preventive treatments such as statins or primary percutaneous coronary intervention in patients with coronary heart disease (CHD) have rendered obsolete the use of measured exercise capacity for assessment of future risk and prognosis. Using a sample of patients from 2 clinical sites, most of whom were taking beta-blockade, antiplatelet, and statin therapy, we hypothesized that peak oxygen consumption (Vo(2)) would remain a strong and independent predictor of all-cause and cardiovascular-specific mortality in men and women with CHD. METHODS We studied 2,812 patients with CHD between 1996 and 2004. All-cause and cardiovascular disease-specific mortality served as end points. RESULTS In all men and women and in a subgroup of patients following evidence-based care, peak Vo(2) remained a strong predictor of all-cause death, with every 1 mL x kg(-1) x min(-1) increase in peak Vo(2) associated with an approximate 15% decrease in risk of death. Among men, a peak Vo(2) (mL x kg(-1) x min(-1)) below approximately 15 was associated with the highest risk, whereas a peak Vo(2) above approximately 19 was associated with a low rate and risk for annual all-cause mortality. Among women, a peak Vo(2) below approximately 12 was associated with the highest risk, whereas a peak Vo(2) above approximately 16.5 was associated with the lowest rate and risk for annual all-cause mortality. CONCLUSIONS In men and women with CHD, peak Vo(2) remains an independent predictor of all-cause and cardiovascular-specific mortality.

Aerobic Capacity in Patients Entering Cardiac Rehabilitation

Background— Symptom-limited treadmill testing is commonly performed on entry to cardiac rehabilitation (CR) for its prognostic value and to design a safe and effective exercise program. Normative values for this evaluation are not available. The primary goals of this study were to establish normative values for peak aerobic capacity (peak &OV0312;o2) for patients entering CR and to create nomograms for conversion of peak &OV0312;o2 to a percentage of predicted exercise capacity, stratified by age, gender, and diagnosis. Methods and Results— Peak &OV0312;o2 was measured in 2896 patients entering CR from 1996 to 2004. Peak &OV0312;o2 was higher in men than in women: 19.3±6.1 mL · kg−1 · min−1 (range, 5.2 to 49.7 mL · kg−1 · min−1) versus 14.5±3.9 mL · kg−1 · min−1 (range, 3.8 to 29.8 mL · kg−1 · min−1) (P<0.0001). Peak &OV0312;o2 decreased steadily with age with a greater rate of decline in men than women (−0.242 versus −0.116 mL · kg−1 · min−1 per year) (P<0.01). Factors associated with lower peak &OV0312;o2 include coronary artery bypass grafting (CABG), angina at stress testing, hypertension, and, in women, &bgr;-blocking medications. Nomograms are presented for individual values to be compared with mean values by age, gender, and cardiac diagnosis. These include a nomogram to convert estimated maximal metabolic equivalents to actual peak &OV0312;o2 for patients who do not undergo direct measurement of peak &OV0312;o2. Conclusions— Values of peak &OV0312;o2 on entry to CR are extremely low, particularly in women, approaching values seen with severe chronic heart failure. This underscores the importance of CR after a major cardiac event to improve physical function and long-term prognosis.

High-Calorie-Expenditure Exercise A New Approach to Cardiac Rehabilitation for Overweight Coronary Patients

Background— More than 80% of patients entering cardiac rehabilitation (CR) are overweight, and >50% have metabolic syndrome. Current CR exercise protocols result in little weight loss and minimal changes in cardiac risk factors. We sought to design an exercise protocol that would lead to greater weight loss and risk factor change. Methods and Results— We performed a randomized controlled clinical trial to evaluate the effect of high-calorie-expenditure exercise (3000- to 3500-kcal/wk exercise-related energy expenditure) compared with standard CR exercise (7 to 800 kcal/wk) on weight loss and risk factors in 74 overweight patients with coronary heart disease. Both groups were counseled for weight loss and taking evidence-based preventive medications. High-calorie-expenditure exercise resulted in double the weight loss (8.2±4 versus 3.7±5 kg; P<0.001) and fat mass loss (5.9±4 versus 2.8±3 kg; P<0.001) and a greater waist reduction (−7±5 versus −5±5 cm; P=0.02) than standard CR exercise at 5 months. High-calorie-expenditure exercise reduced insulin resistance, measured with the euglycemic hyperinsulinemic clamp, along with the ratio of total to high-density lipoprotein cholesterol and components of the metabolic syndrome, more than standard CR exercise (each P<0.01). Overall, fat mass loss best predicted improved metabolic risk, and the prevalence of metabolic syndrome decreased from 59% to 31%. Changes in cardiac risk factors included decreased insulin resistance, increased high-density lipoprotein cholesterol, and decreased measures of insulin, triglycerides, blood pressure, plasminogen activator inhibitor-1, and the ratio of total to high-density lipoprotein cholesterol (each P<0.05). Significant weight loss was maintained at 1 year. Conclusion— High-calorie-expenditure exercise promotes greater weight loss and more favorable cardiometabolic risk profiles than standard CR for overweight coronary patients.Background Over 80% of patients entering cardiac rehabilitation (CR) are overweight and >50% have metabolic syndrome. Current CR exercise protocols result in little weight loss and minimal changes in cardiac risk factors. We sought to design an exercise protocol that would lead to greater weight loss and risk factor change.

Resistance training on physical performance in disabled older female cardiac patients

PURPOSE We evaluated the value of resistance training on measures of physical performance in disabled older women with coronary heart disease (CHD). METHODS The study intervention consisted of a 6-month program of resistance training in a randomized controlled trial format. Training intensity was at 80% of the single-repetition maximal lift. Control patients performed light yoga and breathing exercises. Study participants included 42 women with CHD, all >or= 65 yr of age and community dwelling. Subjects were screened by questionnaire to have low self-reported physical function. The primary study measurements related to the performance of 16 household activities of the Continuous Scale Physical Functional Performance test (CSPFP). These ranged from dressing, to kitchen and cleaning activities, to carrying groceries and walking onto a bus with luggage, and a 6-min walk. Activities were measured in time to complete a task, weight carried during a task, or distance walked. Other measures included body composition, measures of aerobic fitness and strength, and questionnaire-based measures of physical function and depression score. RESULTS Study groups were similar at baseline by age, aerobic capacity, strength, body composition, and in performing the CSPFP. After conditioning, 13 of 16 measured activities were performed more rapidly, or with increased weight carried, compared with the control group (all P < 0.05). Maximal power for activities that involved weight-bearing over a distance, increased by 40% (P < 0.05). CONCLUSIONS Disabled older women with CHD who participate in an intense resistance-training program improve physical capacity over a wide range of household physical activities. Benefits extend beyond strength-related activities, as endurance, balance, coordination, and flexibility all improved. Strength training should be considered an important component in the rehabilitation of older women with CHD.

Effects of Home Versus Supervised Exercise for Patients With Intermittent Claudication

PURPOSE This study was performed to test the efficacy of a supervised, hospital-based exercise program compared with a home-based exercise program involving minimal supervision, for both walking ability and quality of life measures in patients with exercise-limiting intermittent leg claudication. METHODS Twenty-one patients were assigned randomly to 12 weeks of supervised exercise or to a home-based exercise group. After 12 weeks the participants in the supervised group transitioned to a home-based program. Both groups were then reevaluated at the end of 24 weeks. The initial claudication distance (ICD) and absolute claudication distance (ACD) on progressive treadmill exercise was measured at baseline, 12 weeks, and 24 weeks. Additionally, self-reported quality of life status was evaluated using the MOS SF-36 questionnaire. RESULTS Each group improved (P < 0.01) ACD from baseline to 12 weeks, which was sustained at the 24-week follow-up. Both groups experienced similar long-term improvements (P < 0.05) in ACD (521.5 +/- 253.4 meters to 741.9 +/- 365.6 meters for the supervised group, 532.2 +/- 263.5 meters to 715.0 +/- 394.4 meters in the home group, P not significant, between groups). The supervised group experienced a greater improvement (P < 0.01) in the ICD after 12 weeks than the home group but not at 24 weeks. The on-site group also experienced significant improvements in ICD after 24 weeks (P < 0.05). Neither group manifested an improvement in self-reported physical function or mental health as assessed by the MOS SF-36. CONCLUSION A structured exercise program was more effective in improving the ICD over a 24-week period than a less formal, home-based program. However, if patients are screened properly and receive adequate instruction, a home-based program can be a safe, low-cost alternative providing similar long-term (24 weeks) exercise benefits in ACD.

Modest effects of exercise training alone on coronary risk factors and body composition in coronary patients.

BACKGROUND Cardiac rehabilitation programs have evolved to become secondary prevention centers. However, the independent effect of exercise alone on coronary risk factors and body composition in patients with coronary artery disease has not been well studied. OBJECTIVE The aim of this study was to determine the effect of exercise training alone, without modification of dietary intake, on coronary risk factors and body composition in a coronary population. METHODS The authors studied 82 coronary patients (23 females and 59 males) aged 61.2 +/- 12.2 years (mean +/- SD) before and after a 3-month exercise training program. Outcome variables included serum lipid values, glucose, insulin, body composition, body fat distribution, macronutrient intake, and peak aerobic capacity. RESULTS Neither male nor female patients experienced a significant overall improvement in plasma cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, glucose, or insulin levels after the 3-month exercise training program. Dietary macronutrient intake was unaltered during the study period. Peak aerobic capacity increased by 3.4 +/- 4.7 ml/kg/min (17%, P < 0.0001) and high-density lipoprotein (HDL)-cholesterol increased from 38 +/- 10 to 41 +/- 11 mg/dL (8%, P < 0.001) after the rehabilitation program. Patients with baseline triglyceride levels over 200 mg/dL experienced a 22% decrease (from 374 +/- 205 to 293 +/- 190 mg/dL; P < 0.05) after conditioning. Patients with baseline HDL-cholesterol levels under 35 mg/dL also improved overall by 17% (from 29 +/- 3 to 34 +/- 5 mg/dL; P < 0.0001). Exercise-induced changes in plasma HDL-cholesterol were more related to changes in body composition and/or body fat distribution, rather than changes in peak aerobic capacity. CONCLUSION Exercise conditioning alone resulted in relatively modest risk factor improvements in coronary patients after 3 months. High-density lipoprotein cholesterol measures increased by 3 +/- 8 mg/dL (8%). Patients with baseline triglyceride elevations experienced a 22% decrease. On the other hand, there were no overall effects on body weight, total cholesterol, LDL-cholesterol, triglycerides, glucose, or insulin levels. For most patients, exercise effects were minimal and nutritional and medical therapy will need to be used more aggressively to attain nationally recognized risk factor goals.

The Treatment of Obesity in Cardiac Rehabilitation

Obesity is an independent risk factor for the development of coronary heart disease (CHD). At entry into cardiac rehabilitation (CR), more than 80% of patients are overweight and more than 50% have the metabolic syndrome. Yet, CR programs do not generally include weight loss programs as a programmatic component and weight loss outcomes in CR have been abysmal. A recently published study outlines a template for weight reduction based on a combination of behavioral weight loss counseling and an approach to exercise that maximized exercise-related caloric expenditure. This approach to exercise optimally includes walking as the primary exercise modality and eventually requires almost daily longer-distance exercise to maximize caloric expenditure. In addition, lifestyle activities such as stair climbing and avoidance of energy-saving devices should be incorporated into the daily routine. Risk factor benefits of weight loss and exercise training in overweight CHD patients are broad and compelling. Improvements in insulin resistance, lipid profiles, blood pressure, clotting abnormalities, endothelial-dependent vasodilatory capacity, and measures of inflammation such as C-reactive protein have all been demonstrated. Cardiac rehabilitation/secondary prevention programs can no longer ignore the challenge of obesity management in CHD patients. Individual programs need to develop clinically effective and culturally sensitive approaches to weight control. Finally, multicenter randomized clinical trials of weight loss in CHD patients with assessment of long-term clinical outcomes need to be performed.

Changing Clinical Profile of Patients Entering Cardiac Rehabilitation/secondary Prevention Programs: 1996 to 2006

PURPOSE Cardiac rehabilitation (CR)/secondary prevention programming is dependent on clinical attributes of participants. We examined recent changes in the profile of individuals who are entering CR. METHODS We analyzed data for all patients entering our phase II CR program from 1996 to 2006. Patients were classified into 5 groups on the basis of recruitment period: period 1 (1996–1998) (n = 604), period 2 (1999–2000) (n = 571), period 3 (2001–2002) (n = 588), period 4 (2003–2004) (n = 519), and period 5 (2005–2006) (n = 532). RESULTS From period 1 to period 5, age increased from 60.6 to 63.4 years, and the proportion of patients 75 years or older increased by 59%. The proportion of women, initially 25%, did not change. Weight increased from 84.7 to 88.5 kg, whereas the proportion of patients with obesity, diabetes, and hypertension increased by 35%, 52%, and 48%, respectively. However, the proportion of patients with elevated blood pressure level did not change significantly. Peak relative aerobic capacity decreased by 10%. Total cholesterol, triglycerides, and low-density lipoprotein cholesterol decreased by 20%, 35%, and 27%, respectively, whereas high-density lipoprotein cholesterol increased by 12%. Use of all evidence-based cardiovascular drugs increased significantly, particularly statins (from 25% to 77%). CONCLUSIONS CR participants are now older, more frequently present with features of the metabolic syndrome, and are relatively less fit. However, a 3-fold increase in statin use over 10 years has contributed to a marked improvement of lipid parameters.

Cardiac Rehabilitation Participation in Underserved Populations

Cardiac rehabilitation (CR) services in the United States are underutilized and participation is particularly low for racial and ethnic minorities, low socioeconomic status patients, and rural residents. Reduced participation may not only indicate a failure in transitional cardiac care during the inhospital referral process but also could be due to barriers attributed to patients, providers, employers, or medical systems. In-depth analysis of this problem is impeded by difficulties with the identification of underserved groups in clinical settings. Disparities in CR participation certainly contribute to poor medical outcomes in these populations that stand to benefit greatly from lifestyle modifications. It is critical that CR providers survey their communities for underserved populations and coordinate creative efforts aimed at overcoming barriers to participation. Moreover, it is likely that referral to, and participation in, CR will soon be considered a quality indicator, providing further incentive for programs to optimize CR utilization among all eligible patients.

Combined resistive-aerobic training in older patients with coronary artery disease early after myocardial infarction.

BACKGROUND AND PURPOSE Older patients with artery disease have higher rates of disability than younger coronary patients, partly based on lower levels of skeletal muscle strength. We compared the effect of a combined resistive-aerobic training program on muscular strength in older and younger coronary patients early after myocardial infarction. METHODS The study population included 45 patients who had recently (4-12 weeks) suffered a myocardial infarction; 19 were age > or = 62 years (mean 68 +/- 3 years) and 25 were < 60 years of age (mean 48 +/- 7 years). Muscle strength was measured by single repetition maximum lifts for leg extension and bench press, before and after the 12-week conditioning program. Body composition was measured in a subset of 16 patients by dual x-ray absorptiometry. RESULTS At baseline, the older population demonstrated lower strength measures than the younger patients. With conditioning, both groups improved strength similarly with leg-extension and bench press measures increasing by 35% and 14% respectively in the older patients and 39% and 14% in the younger patients (both P < 0.05, NS between groups). Within the older patient group, the men were significantly stronger than the women at baseline yet the women tended to improve their strength measures to a greater degree than the men, increasing leg strength by 66% and bench press by 29% versus 29% and 10% in older men (P < 0.10 between groups). In the overall study population, body composition measures showed a slight decrease in body weight, a decrease in fat mass, and a maintenance of lean body mass and bone mineral content with no difference in response between older and younger patients. CONCLUSIONS Older coronary patients can effectively increase body strength with a combined resistive-aerobic exercise program in the early post-myocardial infarction period.