Reed Humphrey

Increasing Referral and Participation Rates to Outpatient Cardiac Rehabilitation: The Valuable Role of Healthcare Professionals in the Inpatient and Home Health Settings A Science Advisory From the American Heart Association

Cardiovascular disease (CVD) continues to be the leading cause of morbidity and mortality in the United States and worldwide.1 In fact, the prevalence of CVD is on the rise as a function of increased longevity and the mounting effects of cardiac risk factors that typically accumulate over a lifetime. Outpatient cardiac rehabilitation (CR) programs offer a cost-effective, multidisciplinary, comprehensive approach to address these risk factors and to restore individuals to their optimal physiological, psychosocial, nutritional, and functional status.2–6 Thus, the benefits of CR extend well beyond the cardiovascular system, positively affecting an individuals overall health status. These benefits may be particularly important to certain CVD cohorts such as elderly patients who are more likely to present with greater functional limitations and frailty. Additionally, outpatient CR has been shown to dramatically reduce morbidity and mortality by nearly 25% compared with usual care.7,8 Despite the clear benefits of formal, supervised outpatient CR and exercise training programs, as well as strides in automatic referrals,9 current statistics continue to demonstrate that referral and participation rates of eligible patients remain alarmingly low,10–13 with participation particularly poor in rural areas and in eligible patients who have lower socioeconomic status, limited education, advanced age, and/or female sex.14,15 In addition, Gurewich et al16 reported several factors that are likely responsible for the poor referral rates to outpatient CR, which included “the degree of automation and assertiveness in securing referrals, the level of integration of CR within the hospital setting and physician community, the relationship to other CR facilities, and capacity constraints.” Given the continually poor referral and participation rate in outpatient CR despite increased efforts to reverse this trend, additional actions are required. This scientific advisory calls on the inpatient and home healthcare …

Prognostic ability of VE/VCO2 slope calculations using different exercise test time intervals in subjects with heart failure

Background The minute ventilation-carbon dioxide production (VE/VCO2) slope, obtained during exercise testing, possesses prognostic value in heart failure (HF). The VE-VCO2 relationship is generally linear thereby hypothetically producing similar slope values regardless of the exercise-test time interval used for calculation. Design This study assesses the ability of the VE/VCO2 slope, calculated at different time intervals throughout a progressive exercise test, to predict 1-year cardiac-related hospitalization and mortality in subjects with HF. Methods Seventy-two subjects underwent symptom-limited exercise testing with ventilatory expired gas analysis. Mean age and left ventricular ejection fraction for 44 male and 28 female subjects were 51.2 years (± 13.0) and 27.0% (± 12.3) respectively. The VE/VCO2 slope was calculated from time 0 to 25, 50, 75 and 100% of exercise time and subsequently used to create five randomly selected VE/VCO2 slope categories. Results (The intraclass correlation coefficient found calculation of the VE/VCO2 slope, when divided into quartiles, to be a reliable measure (alpha = 0.94, P<0.0001). Univariate Cox regression analysis revealed all VE/VCO2 slope categories (25-100% and random selections) were significant predictors of cardiac-related hospitalization and mortality over a 1-year period. Multivariate Cox regression analysis revealed all VE/VCO2 slope categories outperformed peak oxygen consumption (VO2) in predicting hospitalization and mortality at 1 year. Conclusions Although the different classification schemes were not identical, these results suggest VE/VCO2 slope maintains prognostic significance regardless of exercise-test time interval. Calculation of VE/VCO2 slope may therefore still be valuable in subjects putting forth a sub-maximal effort while effort-dependent measures, such as peak VO2, are not.

Predicting peak oxygen consumption during a conservative ramping protocol implications for the heart failure population

PURPOSE A significant discrepancy between measured oxygen consumption (VO(2)) (via ventilatory expired gas analysis) and estimated VO(2) (via the imposed workload) frequently is reported in the heart failure (HF) population during symptom-limited exercise testing. The purpose of this investigation was to examine the difference between measured and estimated VO(2) (VO(2) discrepancy) during a highly conservative ramping protocol. METHODS For this study, 28 subjects with compensated HF (20 men and 8 women; age, 51.1 +/- 14.6 years) and 19 healthy control subjects (age-, gender-, and activity-matched to an HF subgroup) underwent symptom-limited exercise testing (treadmill) with ventilatory expired gas analysis. RESULTS Peak estimated and measured VO(2) values were significantly higher in the age-, gender-, and activity-matched control group than in the HF group, but the change in measured VO(2) per change in estimated VO(2) (Deltameasured/Deltaestimated VO(2) slope) and the VO(2) discrepancy did not reach statistical significance. Peak estimated VO(2) was a significant predictor of peak measured VO(2) in the overall HF group (R2 = 0.90; P <.001). CONCLUSIONS Although estimated VO(2) is not considered a replacement for measured VO(2), these results indicate that a highly conservative exercise protocol may allow for a more accurate prediction of peak measured VO(2) via the estimated oxygen cost for a given workload in patients with compensated HF.

Cardiac rehabilitation in Europe.

Cardiovascular disease (CVD) remains the main cause of death for men in most European countries, and in all for women. While mortality rates have been declining in most countries, hospital discharge for CVD has been stable since 2004, increasing the pool of patients eligible for cardiac rehabilitation (CR). The physical rehabilitation of patients with CVD has been practiced in Europe to varying degrees since the early 1970s with most countries now engaged in Phase I through Phase III programs. Funding for CR comes from a variety of sources including patient pay, private insurance, retirement and/or obligatory and governmental subsidy. CR is practiced based on best available evidence but participation rates range between 30-50% of eligible patients. Participation rates present one of several challenges and opportunities for future research in Europe, along with assessment of long-term CR outcomes and better extension to primary prevention.

Exercise physiology in patients with left ventricular assist devices.

LVAD use in the heart failure population is increasing and allows severely impaired patients an opportunity for exercise rehabilitation before cardiac transplantation. Although the LVAD provides nearly all of the cardiac output at rest, the native left ventricle contributes a modest amount during exercise, with the LVAD capable of providing a mechanical cardiac output of 10 L/min or greater. Given the parameters of the LVAD, exercise training responses should yield greater changes in submaximal exercise tolerance rather than changes in peak oxygen consumption. Heart rate and LVAD rate are driven by separate mechanisms but increase similarly during exercise. Blood pressure responses are somewhat variable early post LVAD implantation but normalize. Ratings of perceived exertion appear to be reliable and useful in this population. Evidence to date suggests that early mobilization and progressive exercise training in this population is safe and improves the transplantation experience. Although central contributions to oxygen consumption are limited by the inherent mechanical parameters of the LVAD, adequate cardiac output is provided for routine physical activities and moderate exercise training while the patient awaits transplantation.

Exercise, cardiovascular disease, and chronic heart failure

UNLABELLED In addition to patients with coronary artery disease, high-risk patients with severe congestive heart failure can benefit from rehabilitation. Traditionally, such patients were excluded from rehabilitation, but resistive exercise, higher-intensity programs, and interval training have now been safely conducted. Emerging data indicate that exercise training results in a number of improved physiologic and psychologic indices, including neural control, quality of life, exercise tolerance, ventricular function, skeletal muscle physiology, peripheral blood flow, and endothelial function. This review explores these beneficial outcomes through an assessment of therapeutic approaches, with special emphasis on the unique clinical characteristics of patients with congestive heart failure. OVERALL ARTICLE OBJECTIVE To describe the benefits and the evolving role of cardiac rehabilitation for patients with congestive heart failure.

Relationship between ventilatory expired gas and cardiac parameters during symptom-limited exercise testing in patients with heart failure.

PURPOSE This study investigates the relationship between ventilatory expired gas and cardiac parameters measured during exercise testing in patients with heart failure. METHODS Twenty-five subjects (12 male, 13 female) diagnosed with compensated heart failure underwent symptom-limited exercise testing with ventilatory expired gas analysis. Metabolic and cardiac measures of interest were collected during testing. RESULTS Mean peak oxygen consumption (VO2), minute ventilation/carbon dioxide production (VE/VCO2) slope, percentage of age predicted maximal heart rate achieved during exercise testing (%APMHR), and peak respiratory exchange ratio were 14.7 +/- 4.7 mL O2/kg/min-1, 33.8 +/- 9.8, 76% +/- 15%, and 1.1 +/- 0.11, respectively. The VE/VCO2 slope was significantly correlated with the following: %APMHR (r = -0.81, P < 0.001), peak VO2 (r = -0.83, P < 0.001), VO2 at ventilatory threshold (r = -0.70, P < 0.001), and the dead space to tidal volume ratio (VD/Vt) (r = 0.65, P < 0.001). The ability of peak VO2 and %APMHR to predict the VE/VCO2 slope was significant (r = 0.86, r2 = 0.72, P < 0.0001). CONCLUSION This study demonstrates the importance of analyzing multiple exercise test parameters, including metabolic measures, in patients with heart failure.

Function, Eligibility, Outcomes, and Exercise Capacity Associated With Left Ventricular Assist Devices EXERCISE REHABILITATION AND TRAINING FOR PATIENTS WITH VENTRICULAR ASSIST DEVICES

and Drug Administration in the United States, the most widely used of which are systems from Thoratec (formerly Thermo Cardiosystems) (Pleasanton, Calif) and Worldheart’s Novacor (formerly Novacor) (Ottawa, Ontario, Canada). Left ventricular assist devices have been designed with a variety of drive systems, including pneumatic and electric systems. The pneumatic devices significantly limit the patients’ daily function as a result of the sizable mobile external control unit (73 pounds for the Heartmate LVAD).9 The electric devices have two external batteries that can be worn in a shoulder holster or on a belt, allowing for 4 to 6 hours of tether-free support.10 Of the available pneumatic mechanical cardiac assist systems, two are extracorporeal devices (ABIOMED BVS 5000, Danvers, Mass; and Thoratec VAD, Pleasanton, Calif). Both of these units have been used in clinical situations wherein body surface area was less than1.5 m2.11 They seem to be preferred for patients who have been on cardiopulmonary bypass support, and those who require biventricular support.11 Currently, the electric intracorporeal LVAD devices produced by Worldheart (Novacor Left Ventricular Assist System [LVAS]) and Thoratec (Heartmate VE) are the preferred device for function of the LVAD, quality of life, and success in bridging to transplantation or recovery. Moreover, the implantable LVAD may reduce the need in specific cases for heart transplantation, with early intervention and rehabilitation in select cases.12 The current directions of mechanical assistance include development of new total artificial hearts,13 extracardiac assist devices,14 and the new generation of assist R E V I E W A R T I C L E

Altered exercise pulmonary function after left ventricular assist device implantation

The use of LVADs as a bridge to heart transplantation is increasing steadily as more surgical centers add this effective strategy for end-stage heart failure patients. Fundamental exercise physiology in the presence of LVADs has been described previously, and data is available that supports the safety and efficacy of exercise in this population. Variants to the expected exercise response that may be secondary to LVAD implantation, such as the pulmonary restrictive pattern that developed in the patient described in this case study, may occur. Clinicians should consider assessment and monitoring of pulmonary function in this patient population, especially in patients with exercise-induced dyspnea and perhaps patients with pre-existing pulmonary limitation.

Effectiveness of Preoperative Physical Therapy for Elective Cardiac Surgery

<LEAP> highlights the findings and application of Cochrane reviews and other evidence pertinent to the practice of physical therapy. The Cochrane Library is a respected source of reliable evidence related to health care. Cochrane systematic reviews explore the evidence for and against the effectiveness and appropriateness of interventions—medications, surgery, education, nutrition, exercise—and the evidence for and against the use of diagnostic tests for specific conditions. Cochrane reviews are designed to facilitate the decisions of clinicians, patients, and others in health care by providing a careful review and interpretation of research studies published in the scientific literature.1 Each article in this PTJ series summarizes a Cochrane review or other scientific evidence resource on a single topic and will present clinical scenarios based on real patients to illustrate how the results of the review can be used to directly inform clinical decisions. This article focuses on the effectiveness of preoperative physical therapy for elective cardiac surgery. More specifically, does preoperative physical therapy prevent postoperative pulmonary complications in patients undergoing elective cardiac surgery, and, if so, what types of interventions are most effective, and do patients with certain characteristics benefit from therapy? The American Heart Association has reported that the total number of inpatient cardiovascular operations and procedures increased 28% between 2000 and 2010, to 7,588,000 in 2010.2 Despite a decrease in coronary artery bypass graft (CABG) surgery, this surgery remains common; almost 400,000 CABG procedures were performed in the United States in 2010.3 Although there has been a reduction in overall postoperative mortality, there is ample evidence that the risk of pulmonary complications increases morbidity and mortality.2,4