Cardiorespiratory fitness attenuates risk for major adverse cardiac events in hyperlipidemic men and women independent of statin therapy: The Henry Ford ExercIse Testing Project

AIMS

We sought to evaluate the effect of cardiorespiratory fitness (CRF) in predicting mortality, myocardial infarction (MI), and revascularization in patients with hyperlipidemia after stratification by gender and statin therapy.

METHODS AND RESULTS

This retrospective cohort study included 33,204 patients with hyperlipidemia (57 ± 12 years old, 56% men, 25% black) who underwent physician-referred treadmill stress testing at the Henry Ford Health System from 1991 to 2009. Patients were stratified by gender, baseline statin therapy, and estimated metabolic equivalents from stress testing. We computed hazard ratios using Cox regression models after adjusting for demographics, cardiac risk factors, comorbidities, pertinent medications, interaction terms, and indication for stress testing.

RESULTS

There were 4,851 deaths, 1,962 MIs, and 2,686 revascularizations over a median follow-up of 10.3 years. In men and women not on statin therapy and men and women on statin therapy, each 1-metabolic equivalent increment in CRF was associated with hazard ratios of 0.86 (95% CI 0.85-0.88), 0.83 (95% CI 0.81-0.85), 0.85 (95% CI 0.83-0.87), and 0.84 (95% CI 0.81-0.87) for mortality; 0.93 (95% CI 0.90-0.96), 0.87 (95% CI 0.83-0.91), 0.89 (95% CI 0.86-0.92), and 0.90 (95% CI 0.86-0.95) for MI; and 0.91 (95% CI 0.88-0.93), 0.87 (95% CI 0.83-0.91), 0.89 (95% CI 0.87-0.92), and 0.90 (95% CI 0.86-0.94) for revascularization, respectively. No significant interactions were observed between CRF and statin therapy (P > .23).

CONCLUSION

Higher CRF attenuated risk for mortality, MI, and revascularization independent of gender and statin therapy in patients with hyperlipidemia. These results reinforce the prognostic value of CRF and support greater promotion of CRF in this patient population.

Cardiorespiratory fitness and incident diabetes: the FIT (Henry Ford ExercIse Testing) project

OBJECTIVE

Prior evidence has linked higher cardiorespiratory fitness with a lower risk of diabetes in ambulatory populations. Using a demographically diverse study sample, we examined the association of fitness with incident diabetes in 46,979 patients from The Henry Ford ExercIse Testing (FIT) Project without diabetes at baseline.

RESEARCH DESIGN AND METHODS

Fitness was measured during a clinician-referred treadmill stress test performed between 1991 and 2009. Incident diabetes was defined as a new diagnosis of diabetes on three separate consecutive encounters derived from electronic medical records or administrative claims files. Analyses were performed with Cox proportional hazards models and were adjusted for diabetes risk factors.

RESULTS

The mean age was 53 years with 48% women and 27% black patients. Mean metabolic equivalents (METs) achieved was 9.5 (SD 3.0). During a median follow-up period of 5.2 years (interquartile range 2.6-8.3 years), there were 6,851 new diabetes cases (14.6%). After adjustment, patients achieving ≥12 METs had a 54% lower risk of incident diabetes compared with patients achieving <6 METs (hazard ratio 0.46 [95% CI 0.41, 0.51]; P-trend < 0.001). This relationship was preserved across strata of age, sex, race, obesity, hypertension, and hyperlipidemia.

CONCLUSIONS

These data demonstrate that higher fitness is associated with a lower risk of incident diabetes regardless of demographic characteristics and baseline risk factors. Future studies should examine the association between change in fitness over time and incident diabetes.

Rationale and design of the Henry Ford Exercise Testing Project (the FIT project)

Although physical fitness is a powerful prognostic marker in clinical medicine, most cardiovascular population-based studies do not have a direct measurement of cardiorespiratory fitness. In line with the call from the National Heart Lung and Blood Institute for innovative, low-cost, epidemiologic studies leveraging electronic medical record (EMR) data, we describe the rationale and design of the Henry Ford ExercIse Testing Project (The FIT Project). The FIT Project is unique in its combined use of directly measured clinical exercise data retrospective collection of medical history and medication treatment data at the time of the stress test, retrospective supplementation of supporting clinical data using the EMR and administrative databases and epidemiologic follow-up for cardiovascular events and total mortality via linkage with claims files and the death registry. The FIT Project population consists of 69 885 consecutive physician-referred patients (mean age, 54 ± 10 years; 54% males) who underwent Bruce protocol treadmill stress testing at Henry Ford Affiliated Hospitals between 1991 and 2009. Patients were followed for the primary outcomes of death, myocardial infarction, and need for coronary revascularization. The median estimated peak metabolic equivalent (MET) level was 10, with 17% of the patients having a severely reduced fitness level (METs < 6). At the end of the follow-up duration, 15.9%, 5.6%, and 6.7% of the patients suffered all-cause mortality, myocardial infarction, or revascularization procedures, respectively. The FIT Project is the largest study of physical fitness to date. With its use of modern electronic clinical epidemiologic techniques, it is poised to answer many clinically relevant questions related to exercise capacity and prognosis.

Systolic Blood Pressure Response During Exercise Stress Testing: The Henry Ford ExercIse Testing (FIT) Project

Background

The prognostic significance of modest elevations in exercise systolic blood pressure response has not been extensively examined.

Methods and Results

We examined the association between systolic blood pressure response and all-cause death and incident myocardial infarction (MI) in 44 089 (mean age 53±13 years, 45% female, 26% black) patients who underwent exercise treadmill stress testing from the Henry Ford ExercIse Testing (FIT) Project (1991–2010). Exercise systolic blood pressure response was examined as a categorical variable (>20 mm Hg: referent; 1 to 20 mm Hg, and ≤0 mm Hg) and per 1 SD decrease. Cox regression was used to compute hazard ratios (HR) and 95% CI for the association between systolic blood pressure response and all-cause death and incident MI. Over a median follow-up of 10 years, a total of 4782 (11%) deaths occurred and over 5.2 years, a total of 1188 (2.7%) MIs occurred. In a Cox regression analysis adjusted for demographics, physical fitness, and cardiovascular risk factors, an increased risk of death was observed with decreasing systolic blood pressure response (>20 mm Hg: HR=1.0, referent; 1 to 20 mm Hg: HR=1.13, 95% CI=1.05, 1.22; ≤0 mm Hg: HR=1.21, 95% CI=1.09, 1.34). A trend for increased MI risk was observed (>20 mm Hg: HR=1.0, referent; 1 to 20 mm Hg: HR=1.09, 95% CI=0.93, 1.27; ≤0 mm Hg: HR=1.19, 95% CI=0.95, 1.50). Decreases in systolic blood pressure response per 1 SD were associated with an increased risk for all-cause death (HR=1.08, 95% CI=1.05, 1.11) and incident MI (HR=1.09, 95% CI=1.03, 1.16).

Conclusions

Our results suggest that modest increases in exercise systolic blood pressure response are associated with adverse outcomes.

Prognostic significance of depression in blacks with heart failure: insights from Heart Failure: a Controlled Trial Investigating Outcomes of Exercise Training

BACKGROUND

Although studies have shown that depression is associated with worse outcomes in patients with heart failure, most studies have been in white patients. The impact of depression on outcomes in blacks with heart failure has not been studied.

METHODS AND RESULTS

We analyzed 747 blacks and 1420 whites enrolled in Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training, which randomized 2331 patients with ejection fraction ≤35% to usual care with or without exercise training. We examined the association between depressive symptoms assessed by the Beck Depression Inventory-II (BDI-II) at baseline and after 3 months with all-cause mortality/hospitalization. A race by baseline BDI-II interaction was observed (P=0.003) in which elevated baseline scores were associated with worse outcomes in blacks versus whites. In blacks, the association was nonlinear with a hazard ratio of 1.44 (95% confidence interval, 1.24-1.68) when comparing the 75th and 25th percentile of BDI-II (score of 15 and 5, respectively). No race interaction was observed for mortality (P=0.34). There was no differential association between BDI-II change and outcomes in blacks versus whites. In blacks, an increase in BDI-II score from baseline to 3 months was associated with increased mortality/hospitalization (hazard ratio, 1.33; 95% confidence interval, 1.12-1.57 per 10 point increase), whereas a decrease was not related to outcomes.

CONCLUSIONS

In blacks with heart failure, baseline symptoms of depression and worsening of symptoms over time are associated with increased all-cause mortality/hospitalization. Routine assessment of depressive symptoms in blacks with heart failure may help guide management.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00047437.

Authorship in a multicenter clinical trial: The Heart Failure-A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) Authorship and Publication (HAP) scoring system results

BACKGROUND

Few guidelines exist regarding authorship on manuscripts resulting from large multicenter trials. The HF-ACTION investigators devised a system to address assignment of authorship on trial publications and tested the outcomes in the course of conducting the large, multicenter, National Heart, Lung, and Blood Institute-funded trial (n = 2,331; 82 clinical sites; 3 countries). The HF-ACTION Authorship and Publication (HAP) scoring system was designed to enhance rate of dissemination, recognize investigator contributions to the successful conduct of the trial, and harness individual expertise in manuscript generation.

METHODS

The HAP score was generated by assigning points based on investigators' participation in trial enrollment, follow-up, and adherence, as well as participation in committees and other trial activity. Overall publication rates, publication rates by author, publication rates by site, and correlation between site publication and HAP score using a Poisson regression model were examined.

RESULTS

Fifty peer-reviewed, original manuscripts were published within 6.5 years after conclusion of study enrollment. In total, 137 different authors were named in at least 1 publication. Forty-five (55%) of the 82 sites had an author named to at least 1 article. A Poisson regression model examining incident rate ratios revealed that a higher HAP score resulted in a higher incidence of a manuscript, with a 100-point increase in site score corresponding to an approximately 32% increase in the incidence of a published article.

CONCLUSIONS

Given the success in publishing a large number of manuscripts and widely distributing authorship, regular use of a transparent, objective authorship assignment system for publishing results from multicenter trials may be recommended to optimize fairness and dissemination of trial results.

Maximal exercise testing variables and 10-year survival: fitness risk score derivation from the FIT Project

OBJECTIVE

To determine which routinely collected exercise test variables most strongly correlate with survival and to derive a fitness risk score that can be used to predict 10-year survival.

PATIENTS AND METHODS

This was a retrospective cohort study of 58,020 adults aged 18 to 96 years who were free of established heart disease and were referred for an exercise stress test from January 1, 1991, through May 31, 2009. Demographic, clinical, exercise, and mortality data were collected on all patients as part of the Henry Ford ExercIse Testing (FIT) Project. Cox proportional hazards models were used to identify exercise test variables most predictive of survival. A "FIT Treadmill Score" was then derived from the β coefficients of the model with the highest survival discrimination.

RESULTS

The median age of the 58,020 participants was 53 years (interquartile range, 45-62 years), and 28,201 (49%) were female. Over a median of 10 years (interquartile range, 8-14 years), 6456 patients (11%) died. After age and sex, peak metabolic equivalents of task and percentage of maximum predicted heart rate achieved were most highly predictive of survival (P<.001). Subsequent addition of baseline blood pressure and heart rate, change in vital signs, double product, and risk factor data did not further improve survival discrimination. The FIT Treadmill Score, calculated as [percentage of maximum predicted heart rate + 12(metabolic equivalents of task) - 4(age) + 43 if female], ranged from -200 to 200 across the cohort, was near normally distributed, and was found to be highly predictive of 10-year survival (Harrell C statistic, 0.811).

CONCLUSION

The FIT Treadmill Score is easily attainable from any standard exercise test and translates basic treadmill performance measures into a fitness-related mortality risk score. The FIT Treadmill Score should be validated in external populations.

Prognostic value of exercise capacity in patients with coronary artery disease: the FIT (Henry Ford ExercIse Testing) project

OBJECTIVE

To examine the prognostic value of exercise capacity in patients with nonrevascularized and revascularized coronary artery disease (CAD) seen in routine clinical practice.

PATIENTS AND METHODS

We analyzed 9852 adults with known CAD (mean ± SD age, 61±12 years; 69% men [n=6836], 31% black race [n=3005]) from The Henry Ford ExercIse Testing (FIT) Project, a retrospective cohort study of patients who underwent physician-referred stress testing at a single health care system between January 1, 1991, and May 31, 2009. Patients were categorized by revascularization status (nonrevascularized, percutaneous coronary intervention [PCI], or coronary artery bypass graft [CABG] surgery) and by metabolic equivalents (METs) achieved on stress testing. Using Cox regression models, hazard ratios for mortality, myocardial infarction (MI), and downstream revascularizations were calculated after adjusting for potential confounders, including cardiac risk factors, pertinent medications, and stress testing indication.

RESULTS

There were 3824 all-cause deaths during median follow-up of 11.5 years. In addition, 1880 MIs, and 1930 revascularizations were ascertained. Each 1-MET increment in exercise capacity was associated with a hazard ratio (95% CI) of 0.87 (0.85-0.89), 0.87 (0.85-0.90), and 0.86 (0.84-0.89) for mortality; 0.98 (0.96-1.01), 0.88 (0.84-0.92), and 0.93 (0.90-0.97) for MI; and 0.94 (0.92-0.96), 0.91 (0.88-0.95), and 0.96 (0.92-0.99) for downstream revascularizations in the nonrevascularized, PCI, and CABG groups, respectively. In each MET category, the nonrevascularized group had similar mortality risk as and higher MI and downstream revascularization risk than the PCI and CABG surgery groups (P<.05).

CONCLUSION

Exercise capacity was a strong predictor of mortality, MI, and downstream revascularizations in this cohort. Furthermore, patients with similar exercise capacities had an equivalent mortality risk, irrespective of baseline revascularization status.

Relation of resting heart rate to risk for all-cause mortality by gender after considering exercise capacity (the Henry Ford exercise testing project)

Whether resting heart rate (RHR) predicts mortality independent of fitness is not well established, particularly among women. We analyzed data from 56,634 subjects (49% women) without known coronary artery disease or atrial fibrillation who underwent a clinically indicated exercise stress test. Baseline RHR was divided into 5 groups with <60 beats/min as reference. The Social Security Death Index was used to ascertain vital status. Cox hazard models were performed to determine the association of RHR with all-cause mortality, major adverse cardiovascular events, myocardial infarction, or revascularization after sequential adjustment for demographics, cardiovascular disease risk factors, medications, and fitness (metabolic equivalents). The mean age was 53 ± 12 years and mean RHR was 73 ± 12 beats/min. More than half of the participants were referred for chest pain; 81% completed an adequate stress test and mean metabolic equivalents achieved was 9.2 ± 3. There were 6,255 deaths over 11.0-year mean follow-up. There was an increased risk of all-cause mortality with increasing RHR (p trend <0.001). Compared with the lowest RHR group, participants with an RHR ≥90 beats/min had a significantly increased risk of mortality even after adjustment for fitness (hazard ratio 1.22, 95% confidence interval 1.10 to 1.35). This relationship remained significant for men, but not significant for women after adjustment for fitness (p interaction <0.001). No significant associations were seen for men or women with major adverse cardiovascular events, myocardial infarction, or revascularization after accounting for fitness. In conclusion, after adjustment for fitness, elevated RHR was an independent risk factor for all-cause mortality in men but not women, suggesting gender differences in the utility of RHR for risk stratification.

Study of adherence to exercise in heart failure: the HEART camp trial protocol

BACKGROUND

Adherence to the Heart Failure Society of America (HFSA) 2010 guidelines recommending 30 minutes of supervised moderate intensity exercise five days per week is difficult for patients with heart failure (HF). Innovative programs are needed to assist HF patients to adhere to long-term exercise. The objective of this prospective randomized two-group repeated measures experimental design is to determine the efficacy of a behavioral exercise training intervention on long-term adherence to exercise at 18 months in patients with heart failure.

METHODS/DESIGN

A sample size of 246 subjects with heart failure will be recruited over a 3 year period. All subjects receive a cardiopulmonary exercise test and 9 supervised exercise training sessions during a 3 week run-in period prior to randomization. Subjects completing at least 6 of 9 training sessions are randomized to the HEART Camp Intervention group (HC) or to a standard care (SC) exercise group. The HC intervention group receives cognitive-behavioral strategies that address the intervention components of knowledge, attitudes, self-efficacy, behavioral self-management skills and social support. The SC group is provided access to the exercise facility and regular facility staff for the 18 month study period. The primary aim is to evaluate the effect of HEART Camp on adherence to exercise, with our central hypothesis that the HC group will have significantly better adherence to exercise at 18 months. Secondary aims include evaluating which components of the HEART Camp intervention mediate the effects of the intervention on adherence; evaluating the effect of HEART Camp on specific health outcomes; exploring selected demographic variables (race, gender, age) as potential moderators of the effect of the HEART Camp intervention on adherence; and exploring the perceptions and experiences that contextualize exercise adherence.

DISCUSSION

The HEART Camp intervention is the first to test a multi-component intervention designed to improve long-term adherence to exercise behavior in patients with HF. Improving long-term adherence to exercise is the logical first step to ensure the required dose of exercise that is necessary to realize beneficial health outcomes and reduce costs in this burdensome chronic illness.

TRIAL REGISTRATION

Clincaltrials.gov NCT01658670.

Exercise training and implantable cardioverter-defibrillator shocks in patients with heart failure: results from HF-ACTION (Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing)

OBJECTIVES

The purpose of this study was to determine whether exercise training is associated with an increased risk of implantable cardioverter-defibrillator (ICD) therapy in patients with heart failure (HF).

BACKGROUND

Few data are available regarding the safety of exercise training in patients with ICDs and HF.

METHODS

HF-ACTION (Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing) randomized 2,331 outpatients with HF and an ejection fraction (EF) ≤35% to exercise training or usual care. Cox proportional hazards modeling was used to examine the relationship between exercise training and ICD shocks.

RESULTS

We identified 1,053 patients (45%) with an ICD at baseline who were randomized to exercise training (n = 546) or usual care (n = 507). Median age was 61 years old, and median EF was 24%. Over a median of 2.2 years of follow-up, 20% (n = 108) of the exercise patients had a shock versus 22% (n = 113) of the control patients. A history of sustained ventricular tachycardia/fibrillation (hazard ratio [HR]: 1.93 [95% confidence interval (CI): 1.47 to 2.54]), previous atrial fibrillation/flutter (HR: 1.63 [95% CI: 1.22 to 2.18]), exercise-induced dysrhythmia (HR: 1.67 [95% CI: 1.23 to 2.26]), lower diastolic blood pressure (HR for 5-mm Hg decrease <60: 1.35 [95% CI: 1.12 to 1.61]), and nonwhite race (HR: 1.50 [95% CI: 1.13 to 2.00]) were associated with an increased risk of ICD shocks. Exercise training was not associated with the occurrence of ICD shocks (HR: 0.90 [95% CI: 0.69 to 1.18], p = 0.45). The presence of an ICD was not associated with the primary efficacy composite endpoint of death or hospitalization (HR: 0.99 [95% CI: 0.86 to 1.14], p = 0.90).

CONCLUSIONS

We found no evidence of increased ICD shocks in patients with HF and reduced left ventricular function who underwent exercise training. Exercise therapy should not be prohibited in ICD recipients with HF. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437)

Cardiac rehabilitation improves functional capacity and patient-reported health status in patients with continuous-flow left ventricular assist devices: the Rehab-VAD randomized controlled trial

OBJECTIVES

This study examined the effects of a cardiac rehabilitation (CR) program on functional capacity and health status (HS) in patients with newly implanted left ventricular assist devices (LVADs).

BACKGROUND

Reduced functional capacity and HS are independent predictors of mortality in patients with heart failure. CR improves both, and is related to improved outcomes in patients with heart failure; however, there is a paucity of data that describe the effects of CR in patients with LVADs.

METHODS

Enrolled subjects (n = 26; 7 women; age 55 ± 13 years; ejection fraction 21 ± 8%) completed a symptom-limited cardiopulmonary exercise test, the Kansas City Cardiomyopathy Questionnaire (KCCQ), a 6-min walk test (6MW), and single-leg isokinetic strength test before 2:1 randomization to CR versus usual care. Subjects in the CR group underwent 18 visits of aerobic exercise at 60% to 80% of heart rate reserve. Within-group changes from baseline to follow-up were analyzed with a paired t-test, whereas an independent t-test was used to determine differences in the change between groups.

RESULTS

Within-group improvements were observed in the CR group for peak oxygen uptake (10%), treadmill time (3.1 min), KCCQ score (14.4 points), 6MW distance (52.3 m), and leg strength (17%). Significant differences among groups were observed for KCCQ, leg strength, and total treadmill time.

CONCLUSIONS

Indicators of functional capacity and HS are improved in patients with continuous-flow LVADs who attend CR. Future trials should examine the mechanisms responsible for these improvements, and if such improvements translate into improved clinical outcomes. (Cardiac Rehabilitation in Patients With Continuous Flow Left Ventricular Assist Devices:Rehab VAD Trial [RehabVAD]; NCT01584895).

Effects of exercise training on outcomes in women with heart failure: analysis of HF-ACTION (Heart Failure-A Controlled Trial Investigating Outcomes of Exercise TraiNing) by sex

OBJECTIVES

The authors hypothesized that the women enrolled in the HF-ACTION (Heart Failure-A Controlled Trial Investigating Outcomes of Exercise TraiNing) trial and randomly assigned to exercise training (ET) would improve functional capacity as measured by peak oxygen uptake (VO2) compared with those in the usual care group. Furthermore, they hypothesized that the improvement in peak VO2 would correlate with prognosis. They explored whether exercise had a differential effect on outcomes in women versus men.

BACKGROUND

There is less evidence for the benefit of ET in women with heart failure (HF) compared with men because of the small numbers of women studied.

METHODS

HF-ACTION was a randomized trial of ET versus usual care in 2,331 patients with class II-IV HF and a left ventricular ejection fraction of ≤35%. Sex differences in the effects of randomized treatment on clinical outcomes were assessed through the use of a series of Cox proportional hazards models, controlling for covariates known to affect prognosis in HF-ACTION.

RESULTS

Women had lower baseline peak VO2 and 6-min walk distance than did men (median, 13.4 vs. 14.9 ml/min/kg and 353 vs. 378 m, respectively). An increase in peak VO2 at 3 months was present in women and men in the ET group (mean ± SD; median, 0.88 ± 2.2, 0.80 and 0.77 ± 2.7, 0.60, respectively, women vs. men; p = 0.42). Women randomly assigned to ET had a significant reduction in the primary endpoint, (hazard ratio: 0.74) compared with men (hazard ratio: 0.99) randomly assigned to ET, with a significant treatment-by-sex interaction (p = 0.027).

CONCLUSIONS

Although there is no significant difference between men and women in the effect of ET on peak VO2 change at 3 months, ET in women with HF is associated with a larger reduction in rate of the combined endpoint of all-cause mortality and hospital stay than in men.

Cardiac rehabilitation exercise and self-care for chronic heart failure

Chronic heart failure (CHF) is highly prevalent in older individuals and is a major cause of morbidity, mortality, hospitalizations, and disability. Cardiac rehabilitation (CR) exercise training and CHF self-care counseling have each been shown to improve clinical status and clinical outcomes in CHF. Systematic reviews and meta-analyses of CR exercise training alone (without counseling) have demonstrated consistent improvements in CHF symptoms in addition to reductions in cardiac mortality and number of hospitalizations, although individual trials have been less conclusive of the latter 2 findings. The largest single trial, HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training), showed a reduction in the adjusted risk for the combined endpoint of all-cause mortality or hospitalization (hazard ratio: 0.89, 95% confidence interval: 0.81 to 0.99; p = 0.03). Quality of life and mental depression also improved. CHF-related counseling, whether provided in isolation or in combination with CR exercise training, improves clinical outcomes and reduces CHF-related hospitalizations. We review current evidence on the benefits and risks of CR and self-care counseling in patients with CHF, provide recommendations for patient selection for third-party payers, and discuss the role of CR in promoting self-care and behavioral changes.

Race, exercise training, and outcomes in chronic heart failure: findings from Heart Failure - a Controlled Trial Investigating Outcomes in Exercise TraiNing (HF-ACTION)

BACKGROUND

The strength of race as an independent predictor of long-term outcomes in a contemporary chronic heart failure (HF) population and its association with exercise training response have not been well established. We aimed to investigate the association between race and outcomes and to explore interactions with exercise training in patients with ambulatory HF.

METHODS

We performed an analysis of HF-ACTION, which randomized 2331 patients with HF having an ejection fraction ≤35% to usual care with or without exercise training. We examined characteristics and outcomes (mortality/hospitalization, mortality, and cardiovascular mortality/HF hospitalization) by race using adjusted Cox models and explored an interaction with exercise training.

RESULTS

There were 749 self-identified black patients (33%). Blacks were younger with significantly more hypertension and diabetes, less ischemic etiology, and lower socioeconomic status versus whites. Blacks had shorter 6-minute walk distance and lower peak VO2 at baseline. Over a median follow-up of 2.5 years, black race was associated with increased risk for all outcomes except mortality. After multivariable adjustment, black race was associated with increased mortality/hospitalization (hazard ratio [HR] 1.16, 95% CI 1.01-1.33) and cardiovascular mortality/HF hospitalization (HR 1.46, 95% CI 1.20-1.77). The hazard associated with black race was largely caused by increased HF hospitalization (HR 1.58, 95% CI 1.27-1.96), given similar cardiovascular mortality. There was no interaction between race and exercise training on outcomes (P > .5).

CONCLUSIONS

Black race in patients with chronic HF was associated with increased prevalence of modifiable risk factors, lower exercise performance, and increased HF hospitalization, but not increased mortality or a differential response to exercise training.

Association between resting heart rate, chronotropic index, and long-term outcomes in patients with heart failure receiving β-blocker therapy: data from the HF-ACTION trial

AIMS

The aim of this study was to assess the association between resting heart rate (HR), chronotropic index (CI), and clinical outcomes in optimally treated chronic heart failure (HF) patients on β-blocker therapy.

METHODS AND RESULTS

We performed a sub-study in 1118 patients with HF and reduced ejection fraction (EF < 35%) included in the HF-ACTION trial. Patients in sinus rhythm who received a β-blocker and who performed with maximal effort on the exercise test were included. Chronotropic index was calculated as an index of HR reserve achieved, by using the equation (220-age) for estimating maximum HR. A sensitivity analysis using an equation developed for HF patients on β-blockers was also performed. Cox proportional hazards models were fit to assess the association between CI and clinical outcomes. Median (25th, 75th percentiles) follow-up was 32 (21, 44) months. In a multivariable model including resting HR and CI as continuous variables, neither was associated with the primary outcome of all-cause mortality or hospitalization. However, each 0.1 unit decrease in CI <0.6 was associated with 17% increased risk of all-cause mortality (hazard ratio 1.17, 95% confidence interval 1.01-1.36; P = 0.036), and 13% increased risk of cardiovascular mortality or HF hospitalization (hazard ratio 1.13, 1.02-1.26; P = 0.025). Overall, 666 of 1118 (60%) patients had a CI <0.6. Chronotropic index did not retain statistical significance when dichotomized at a value of ≤ 0.62.

CONCLUSION

In HF patients receiving optimal medical therapy, a decrease in CI <0.6 was associated with adverse clinical outcomes. Obtaining an optimal HR response to exercise, even in patients receiving optimal β-blocker therapy, may be a therapeutic target in the HF population.

Clinical characteristics, response to exercise training, and outcomes in patients with heart failure and chronic obstructive pulmonary disease: findings from Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing (HF-ACTION)

BACKGROUND

The aim of this study was to investigate the clinical characteristics, exercise training response, β-blocker selectivity, and outcomes in patients with heart failure (HF) and chronic obstructive pulmonary disease (COPD).

METHODS

We performed an analysis of HF-ACTION, which randomized 2,331 patients with HF having an ejection fraction of ≤35% to usual care with or without aerobic exercise training. We examined clinical characteristics and outcomes (mortality/hospitalization, mortality, cardiovascular [CV] mortality/CV hospitalization, and CV mortality/HF hospitalization) by physician-reported COPD status using adjusted Cox models and explored an interaction with exercise training. The interaction between β-blocker cardioselectivity and outcomes was investigated.

RESULTS

Of patients with COPD status documented (n = 2311), 11% (n = 249) had COPD. Patients with COPD were older, had more comorbidities, and had lower use of β-blockers compared with those without COPD. At baseline, patients with COPD had lower peak oxygen consumption and higher V(E)/V(CO)(2) slope. During a median follow-up of 2.5 years, COPD was associated with increased mortality/hospitalization, mortality, and CV mortality/HF hospitalization. After multivariable adjustment, the risk of CV mortality/HF hospitalization remained increased (hazard ratio [HR] 1.46, 95% CI 1.14-1.87), whereas mortality/hospitalization (HR 1.15, 95% CI 0.96-1.37) and mortality (HR 1.33, 95% CI 0.99-1.76) were not significantly increased. There was no interaction between COPD and exercise training on outcomes or between COPD and β-blocker selectivity on mortality/hospitalization (all P > .1).

CONCLUSIONS

Chronic obstructive pulmonary disease in patients with HF was associated with older age, more comorbidities, reduced exercise capacity, and increased CV mortality/HF hospitalization, but not a differential response to exercise training. β-Blocker selectivity was not associated with differences in outcome for patients with vs without COPD.

An early appointment to outpatient cardiac rehabilitation at hospital discharge improves attendance at orientation: a randomized, single-blind, controlled trial

BACKGROUND

Outpatient cardiac rehabilitation (CR) decreases mortality rates but is underutilized. Current median time from hospital discharge to enrollment is 35 days. We hypothesized that an appointment within 10 days would improve attendance at CR orientation.

METHODS AND RESULTS

At hospital discharge, 148 patients with a nonsurgical qualifying diagnosis for CR were randomized to receive a CR orientation appointment either within 10 days (early) or at 35 days (standard). The primary end point was attendance at CR orientation. Secondary outcome measures were attendance at ≥1 exercise session, the total number of exercise sessions attended, completion of CR, and change in exercise training workload while in CR. Average age was 60±12 years; 56% of participants were male and 49% were black, with balanced baseline characteristics between groups. Median time (95% confidence interval) to orientation was 8.5 (7-13) versus 42 (35 to NA [not applicable]) days for the early and standard appointment groups, respectively (P<0.001). Attendance rates at the orientation session were 77% (57/74) versus 59% (44/74) in the early and standard appointment groups, respectively, which demonstrates a significant 18% absolute and 56% relative improvement (relative risk, 1.56; 95% confidence interval, 1.03-2.37; P=0.022). The number needed to treat was 5.7. There was no difference (P>0.05) in any of the secondary outcome measures, but statistical power for these end points was low. Safety analysis demonstrated no difference between groups in CR-related adverse events.

CONCLUSIONS

Early appointments for CR significantly improve attendance at orientation. This simple technique could potentially increase initial CR participation nationwide.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01596036.

Randomized controlled trial comparing simultaneous versus optimized sequential interventricular stimulation during cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality and improves symptoms in patients with systolic heart failure (HF) and ventricular dyssynchrony. This randomized, double-blind, controlled study evaluated whether optimizing the interventricular stimulating interval (V-V) to sequentially activate the ventricles is clinically better than simultaneous V-V stimulation during CRT.

METHODS

Patients with New York Heart Association (NYHA) III or IV HF, meeting both CRT and implantable cardioverter-defibrillator indications, randomly received either simultaneous CRT or CRT with optimized V-V settings for 6 months. Patients also underwent echocardiography-guided atrioventricular delay optimization to maximize left ventricular filling. The V-V optimization involved minimizing the left ventricular septal to posterior wall motion delay during CRT. The primary objective was to demonstrate noninferiority using a clinical composite end point that included mortality, HF hospitalization, NYHA functional class, and patient global assessment. Secondary end points included changes in NYHA classification, 6-minute hall walk distance, quality of life, peak VO(2), and event-free survival.

RESULTS

The composite score improved in 75 (64.7%) of 116 simultaneous patients and in 92 (75.4%) of 122 optimized patients (P < .001, for noninferiority). A prespecified test of superiority showed that more optimized patients improved (P = .03). New York Heart Association functional class improved in 58.0% of simultaneous patients versus 75.0% of optimized patients (P = .01). No significant differences in exercise capacity, quality of life, peak VO(2), or HF-related event rate between the 2 groups were observed.

CONCLUSIONS

These findings demonstrate modest clinical benefit with optimized sequential V-V stimulation during CRT in patients with NYHA class III and IV HF. Optimizing V-V timing may provide an additional tool for increasing the proportion of patients who respond to CRT.

Relation between volume of exercise and clinical outcomes in patients with heart failure

OBJECTIVES

This study determined whether greater volumes of exercise were associated with greater reductions in clinical events.

BACKGROUND

The HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) trial showed that among patients with heart failure (HF), regular exercise confers a modest reduction in the adjusted risk for all-cause mortality or hospitalization.

METHODS

Patients randomized to the exercise training arm of HF-ACTION who were event-free at 3 months after randomization were included (n = 959). Median follow-up was 28.2 months. Clinical endpoints were all-cause mortality or hospitalization and cardiovascular mortality or HF hospitalization.

RESULTS

A reverse J-shaped association was observed between exercise volume and adjusted clinical risk. On the basis of Cox regression, exercise volume was not a significant linear predictor but was a logarithmic predictor (p = 0.03) for all-cause mortality or hospitalization. For cardiovascular mortality or HF hospitalization, exercise volume was a significant (p = 0.001) linear and logarithmic predictor. Moderate exercise volumes of 3 to <5 metabolic equivalent (MET)-h and 5 to <7 MET-h per week were associated with reductions in subsequent risk that exceeded 30%. Exercise volume was positively associated with the change in peak oxygen uptake at 3 months (r = 0.10; p = 0.005).

CONCLUSIONS

In patients with chronic systolic HF, volume of exercise is associated with the risk for clinical events, with only moderate levels (3 to 7 MET-h per week) of exercise needed to observe a clinical benefit. Although further study is warranted to confirm the relationship between volume of exercise completed and clinical events, our findings support the use of regular exercise in the management of these patients.

Randomized controlled trial comparing simultaneous versus optimized sequential interventricular stimulation during cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality and improves symptoms in patients with systolic heart failure (HF) and ventricular dyssynchrony. This randomized, double-blind, controlled study evaluated whether optimizing the interventricular stimulating interval (V-V) to sequentially activate the ventricles is clinically better than simultaneous V-V stimulation during CRT.

METHODS

Patients with New York Heart Association (NYHA) III or IV HF, meeting both CRT and implantable cardioverter-defibrillator indications, randomly received either simultaneous CRT or CRT with optimized V-V settings for 6 months. Patients also underwent echocardiography-guided atrioventricular delay optimization to maximize left ventricular filling. The V-V optimization involved minimizing the left ventricular septal to posterior wall motion delay during CRT. The primary objective was to demonstrate noninferiority using a clinical composite end point that included mortality, HF hospitalization, NYHA functional class, and patient global assessment. Secondary end points included changes in NYHA classification, 6-minute hall walk distance, quality of life, peak VO(2), and event-free survival.

RESULTS

The composite score improved in 75 (64.7%) of 116 simultaneous patients and in 92 (75.4%) of 122 optimized patients (P < .001, for noninferiority). A prespecified test of superiority showed that more optimized patients improved (P = .03). New York Heart Association functional class improved in 58.0% of simultaneous patients versus 75.0% of optimized patients (P = .01). No significant differences in exercise capacity, quality of life, peak VO(2), or HF-related event rate between the 2 groups were observed.

CONCLUSIONS

These findings demonstrate modest clinical benefit with optimized sequential V-V stimulation during CRT in patients with NYHA class III and IV HF. Optimizing V-V timing may provide an additional tool for increasing the proportion of patients who respond to CRT.

Current status of preventive cardiology training among United States cardiology fellowships and comparison to training guidelines

We evaluated preventive cardiology education in United States cardiology fellowship programs and their adherence to Core Cardiovascular Training Symposium training guidelines, which recommend 1 month of training, faculty with expertise, and clinical experience in cardiac rehabilitation, lipid disorder management, and diabetes management as a part of the prevention curricula. We sent an anonymous survey to United States cardiology program directors and their chief fellow. The survey assessed the program curricula, rotation structure, faculty expertise, obstacles, and recommended improvements. The results revealed that 24% of surveyed programs met the Core Cardiovascular Training Symposium guidelines with a dedicated 1-month rotation in preventive cardiology, 24% had no formalized training in preventive cardiology, and 30% had no faculty with expertise in preventive cardiology, which correlated with fewer rotations in prevention than those with specialized faculty (p = 0.009). Fellows rotated though the following experiences (% of programs): cardiac rehabilitation, 71%; lipid management, 37%; hypertension, 15%; diabetes, 7%; weight management/obesity, 6%; cardiac nutrition, 6%; and smoking cessation, 5%. The program directors cited "lack of time" as the greatest obstacle to providing preventive cardiology training and the chief fellows reported "lack of a developed curriculum" (p = 0.01). The most recommended improvement was for the American College of Cardiology to develop a web-based curriculum/module. In conclusion, most surveyed United States cardiology training programs currently do not adhere to basic preventive cardiovascular medicine Core Cardiovascular Training Symposium recommendations. Additional attention to developing curricular content and structure, including the creation of an American College of Cardiology on-line knowledge module might improve fellowship training in preventive cardiology.

Predicting maximal HR in heart failure patients on β-blockade therapy

PURPOSE

Standards for estimating maximal HR are important when interpreting the adequacy of physiologic stress during exercise testing, assessing chronotropic response, and prescribing an exercise training regimen. The equation 220 - age is used to estimate maximum HR; however, it overestimates measured maximal HR in patients taking β-adrenergic blockade (βB) therapy. This study developed and validated a practical equation to predict maximal HR in patients with heart failure (HF) taking βB therapy.

METHODS

Data from symptom-limited exercise tests completed on patients with systolic HF participating in the Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training trial and taking a βB agent were used to develop a simplified equation, which was validated using bootstrapping.

RESULTS

The simplified derived equation was 119 + 0.5 (resting HR) - 0.5 (age) - (0, if test was completed using a treadmill; 5, if using a stationary bike). The R2 and SEE were 0.28 and 18 beats·min(-1), respectively. Validation of this equation yielded a mean R and SEE of 0.28 and 18 beats·min(-1), respectively. For the equation 220 - age, the R2 was -2.93, and the SEE was 43 beats·min(-1).

CONCLUSIONS

We report a valid and simple population-specific equation for estimating peak HR in patients with HF taking βB therapy. This equation should be helpful when evaluating chronotropic response or assessing if a maximum effort was provided during exercise testing. We caution, however, that the magnitude of the variation (SEE = 18 beats·min(-1)) associated with this prediction equation may make it impractical when prescribing exercise intensity.

Subspecialty training in preventive cardiology: the current status and discoverable fellowship programs

BACKGROUND

Preventive cardiology is currently not an American Board of Medical Specialties-recognized subspecialty. However, several programs offer non-accredited fellowships throughout the country. No source currently exists listing all available programs, and finding programs requires time-intensive search strategies. Our aim was to find all current preventive cardiology fellowships in the United States and describe their basic structure, duties, and faculty.

METHODS

We searched the Internet, contacted national organizations, and networked through any institution thought likely to have a fellowship.

RESULTS

We found 15 programs currently offering subspecialty training in preventive cardiology but with considerably different styles, structures, duties, clinical time, lengths, and hosting departments.

CONCLUSIONS

We provided a list of these programs and discussed the implications for the future of formal subspecialty preventive cardiology education.

Benefit of exercise therapy for systolic heart failure in relation to disease severity and etiology-findings from the Heart Failure and A Controlled Trial Investigating Outcomes of Exercise Training study

BACKGROUND

This post hoc analysis of the HF-ACTION cohort explores the primary and secondary results of the HF-ACTION study by etiology and severity of illness.

METHODS

HF-ACTION randomized stable outpatients with reduced left ventricular (LV) function and heart failure (HF) symptoms to either supervised exercise training plus usual care or to usual care alone. The primary outcome was all-cause mortality or all-cause hospitalization; secondary outcomes included all-cause mortality, cardiovascular mortality or cardiovascular hospitalization, and cardiovascular mortality or HF hospitalization. The interaction between treatment and risk variable, etiology or severity as determined by risk score, New York Heart Association class, and duration of cardiopulmonary exercise test was examined in a Cox proportional hazards model for all clinical end points.

RESULTS

There was no interaction between etiology and treatment for the primary outcome (P = .73), cardiovascular (CV) mortality or CV hospitalization (P = .59), or CV mortality or HF hospitalization (P = .07). There was a significant interaction between etiology and treatment for the outcome of mortality (P = .03), but the interaction was no longer significant when adjusted for HF-ACTION adjustment model predictors (P = .08). There was no significant interaction between treatment effect and severity, except a significant interaction between cardiopulmonary exercise duration and training was identified for the primary outcome of all-cause mortality or all-cause hospitalization.

CONCLUSION

Consideration of symptomatic (New York Heart Association classes II to IV) patients with HF with reduced LV function for participation in an exercise training program should be made independent of the cause of HF or the severity of the symptoms.

Factors related to morbidity and mortality in patients with chronic heart failure with systolic dysfunction: the HF-ACTION predictive risk score model

BACKGROUND

We aimed to develop a multivariable statistical model for risk stratification in patients with chronic heart failure with systolic dysfunction, using patient data that are routinely collected and easily obtained at the time of initial presentation.

METHODS AND RESULTS

In a cohort of 2331 patients enrolled in the HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise TraiNing) study (New York Heart Association class II-IV, left ventricular ejection fraction ≤0.35, randomized to exercise training and usual care versus usual care alone, median follow-up of 2.5 years), we performed risk modeling using Cox proportional hazards models and analyzed the relationship between baseline clinical factors and the primary composite end point of death or all-cause hospitalization and the secondary end point of all-cause death alone. Prognostic relationships for continuous variables were examined using restricted cubic spline functions, and key predictors were identified using a backward variable selection process and bootstrapping methods. For ease of use in clinical practice, point-based risk scores were developed from the risk models. Exercise duration on the baseline cardiopulmonary exercise test was the most important predictor of both the primary end point and all-cause death. Additional important predictors for the primary end point risk model (in descending strength) were Kansas City Cardiomyopathy Questionnaire symptom stability score, higher serum urea nitrogen, and male sex (all P<0.0001). Important additional predictors for the mortality risk model were higher serum urea nitrogen, male sex, and lower body mass index (all P<0.0001).

CONCLUSIONS

Risk models using simple, readily obtainable clinical characteristics can provide important prognostic information in ambulatory patients with chronic heart failure with systolic dysfunction.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00047437.

Is social isolation/alienation confounded with, and non-independent of, emotional distress in its association with early onset of coronary artery disease?

Both emotional distress (ED) and social isolation/alienation (SI/A) have been found to prospectively predict adverse cardiac events, but few studies have tested the confounding/redundancy of these measures as correlates/predictors of outcomes. In this study, 163 patients with documented coronary artery disease (CAD) were interviewed for multiple indices of SI/A and administered the Symptom Checklist 90 - Revised (SCL90R). A spouse or friend provided an independent rating of ED using the spouse/friend version of the Ketterer Stress Symptom Frequency Checklist (KSSFC). The measures of ED and SI/A covaried. All three scales from the KSSFC (depression, anxiety, and "AIAI" - aggravation, irritation, anger, and impatience), and three scales from the SCL90R (anxiety, depression, and psychoticism), were associated with early Age at Initial Diagnosis (AAID) of CAD. Neither three scales derived from the SCL90R (shyness, feeling abused, and feeling lonely) nor the interview indices of SI/A (married, living alone, having a confidant, self description as a lone wolf, and self-description as lonely) were associated with early AAID. Thus, it is concluded that the present results indicate that ED and SI/A are confounded and that, even when tested head-to-head in a multivariate analysis, only ED is associated with AAID.

Social network and health outcomes among African American cardiac rehabilitation patients

OBJECTIVE

We tested the hypotheses that the number of close social network members and the health-related support provided by social network members are predictive of coping efficacy and health behaviors.

METHODS

Cross-sectional data were collected from 115 African Americans enrolled in cardiac rehabilitation. Measures included the social convoy model, SF-36, the Social Interaction Questionnaire, the Patient Self-Efficacy Questionnaire, and an investigator-developed assessment of health behaviors.

RESULTS

Bivariate relationships were found between the number of inner network members and coping efficacy (r = .19, P < .05) and health behaviors (r = .18, P < .06), and between health-related support and coping efficacy (r = .22, P < .05) and health behaviors (r = .28, P < .001). Regression analyses support the hypothesis that close network members predicted better coping efficacy (β = .18, P < .05) and health behaviors (β = .19, P < .05). Health-related support also predicted coping efficacy (β = .23, P < .05) and health behaviors (β = .30, P < .01).

CONCLUSION

African Americans with larger inner networks have more health support, better health behaviors, and higher coping efficacy. The number of close social network members and related health-support promote health through health behaviors and coping efficacy.

Role and benefits of exercise in the management of patients with heart failure

Initial research established the feasibility of exercise training in patients with heart failure, as well as associated physiological benefits. This review summarizes the findings from over two dozen single-site studies that address the effect of exercise training on exercise capacity and cardiovascular and peripheral function. In addition, it incorporates the results from two meta-analyses and a recently completed multi-center trial, all of which studied the effects of exercise training on clinical outcomes. The major conclusions from these studies are that exercise training is safe; improves health status and exercise capacity; helps attenuate much of the abnormal pathophysiology that develops with heart failure; and yields a modest reduction in clinical events. The magnitude of the clinical benefits appears related to the volume of exercise completed. Future research is needed to identify which patient subgroups might benefit the most from exercise training, the optimal exercise dose or load needed to lessen disease-related symptoms and maximize clinical benefit, and the effects of exercise training in patients with heart failure and preserved left ventricular systolic function.

Exercise self-regulation among older women participating in a heart disease-management intervention

Using behavioral self-regulation processes may facilitate exercise among older women with heart disease. Data from women in a heart disease-management program (n = 658, mean 73 years), was used to explore associations among exercise self-regulation components (i.e., choosing to improve exercise and observing, judging, and reacting to one's behavior) and exercise capacity. General linear models showed that choosing exercise predicted higher exercise self-regulation scores postprogram and 8 months later. In turn, these scores predicted greater improvements in exercise capacity concurrently and 8 months later. Interaction analyses revealed that the effect of self-regulation on exercise capacity was stronger among women who chose to work on exercise.

Healthcare utilization and emotional distress in coronary artery disease patients

BACKGROUND

No studies to-date have examined the various types of emotional distress (ED) for their relative power at predicting costs in patients with coronary artery disease (CAD).

OBJECTIVE

The authors investigated the association between expenditure for CAD patients and various measures of emotional/psychological functioning.

METHOD

The authors assessed dollars spent in relation to dimensions of the Symptom Checklist 90-Revised and traditional risk factors in the year preceding referral of 164 CAD patients for stress management.

RESULTS

Total costs were associated with the Anxiety, Phobic Anxiety, and Psychoticism scales. Hypertension was also associated with increased costs.

CONCLUSIONS

Present results indicate an association of higher costs with anxiety. Because the symptoms of anxiety overlap with those of cardiac disease, increased vigilance by both patients and practitioners, resulting in more testing and longer hospital stays is not surprising. Results suggest that there is a potential for substantial cost savings with enhanced detection and treatment of anxiety-spectrum emotional distress.