Pack, Quinn R.

Cardiac rehabilitation (CR) is a guideline-recommended, multidisciplinary program of exercise training, risk factor management, and psychosocial counseling for people with cardiovascular disease (CVD) that is beneficial but underused and with substantial disparities in referral, access, and participation. The emergence of new virtual and remote delivery models has the potential to improve access to and participation in CR and ultimately improve outcomes for people with CVD. Although data suggest that new delivery models for CR have safety and efficacy similar to traditional in-person CR, questions remain regarding which participants are most likely to benefit from these models, how and where such programs should be delivered, and their effect on outcomes in diverse populations. In this review, we describe important gaps in evidence, identify relevant research questions, and propose strategies for addressing them. We highlight 4 research priorities: (1) including diverse populations in all CR research; (2) leveraging implementation methodologies to enhance equitable delivery of CR; (3) clarifying which populations are most likely to benefit from virtual and remote CR; and (4) comparing traditional in-person CR with virtual and remote CR in diverse populations using multicenter studies of important clinical, psychosocial, and cost-effectiveness outcomes that are relevant to patients, caregivers, providers, health systems, and payors. By framing these important questions, we hope to advance toward a goal of delivering high-quality CR to as many people as possible to improve outcomes in those with CVD.

Background: Cardiac rehabilitation (CR) improves functional capacity after heart valve surgery (HVS), but no survival benefit has yet been described. We hypothesized that attendance at CR after HVS would be associated with improved long-term survival. Methods: In 2013, we surveyed all patients (or a close family member if the patient was deceased) who had isolated HVS between 2006 through 2010 at the Mayo Clinic to assess if they attended CR after their HVS. We assessed survey reliability among local patients by comparing self-reported vs. medical-record verified CR attendance with the kappa statistic. We then performed a propensity-adjusted landmark mortality analysis through October 2014 for the association between CR attendance and long-term all-cause mortality conditional upon surviving the first year after HVS. Results: Survey response rate was 40% (573/1420), with responders more likely to be older, have longer hospitalizations, more aortic valve disease, but have better survival than non-responders. Among local patients, there was “substantial” agreement between reported attendance and medical-record verified CR attendance (agreement at 84%, kappa = 0.62.) A total of 547 patients (age 70 yrs., 62% male, 59% aortic valve surgery) with valid survey responses were included in the propensity analysis, of whom 296 (54.1%) attended CR. There were 100 deaths during a median follow-up of 5.4 years. For all patients, the propensity-adjusted model suggested no impact of CR on mortality (HR 1.03, 95% CI, 0.66 to 1.62). When stratified by procedure type, results suggested a potentially favorable, but non-significant, effect among patients with mitral valve surgery (HR 0.49, 95% CI 0.15 to 1.56), but not among patients with aortic valve surgery (HR 1.00, 95% CI 0.61 to 1.64.) Conclusions: Important improvements in functional capacity from CR have been previously reported after HVS, but, contrary to our hypothesis, we found that CR does not provide long-term survival benefits after HVS. These findings need additional confirmation to better clarify any mortality impact that may exist for CR following HVS, particularly among patients undergoing mitral valve surgery.

Background: Participation in cardiac rehabilitation (CR) has been shown to decrease mortality following acute myocardial infarction (MI), but its impact on rehospitalizations requires examination. Methods: We included patients who were hospitalized with first-ever MI in Olmsted County Minnesota from 1987-2010 and survived to hospital discharge. Participation in CR within the first 30 days following MI was determined using billing data and was analyzed as a time-dependent covariate. The association between CR participation and all-cause rehospitalization was analyzed using Andersen-Gill models to account for repeated events. As CR participation is a non-randomized intervention, we adjusted for propensity to participate after fitting a logistic regression model using 13 factors significantly associated with participation on univariate analysis. Patients were censored at the time of death or last follow-up. Results: Among 2991 patients (mean age 67 years, 59% male, 31% ST elevation MI), 1480 (49%) participated in CR following acute MI hospital discharge (first session occurred at a mean of 9 days post-discharge). Most patients (75%) were rehospitalized at least once during a mean follow-up of 7.6 years, and CR participation was associated with reduced risk of rehospitalization. The rehospitalization rates were 39% and 59% at one year for participants and non-participants, respectively. In unadjusted analysis, CR participation was associated with a markedly decreased risk of rehospitalization (HR 0.51, 95% CI 0.49-0.53, p<0.001). After adjusting for propensity to participate, the association between CR participation and all-cause rehospitalization persisted (HR 0.70, 95% CI 0.67-0.73, p<0.001). Conclusions: CR participation is associated with a markedly reduced risk of rehospitalization after incident MI. In addition to reducing mortality, improving CR participation rates may have a large impact post-MI healthcare resource use.

Introduction: Cardiac rehabilitation (CR) is an effective but highly underutilized therapy for heart disease. Efforts are underway to increase CR referral and enrollment, but little is known about the potential capacity for growth in CR utilization in the United States. To address this concern, we estimated the current national capacity of CR programs across the United States and assessed obstacles to potential growth. Methods: We surveyed all CR Program Directors listed in the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR) database in November of 2012. Respondents reported current enrollment levels, current program capacity, program capacity given reasonable expansion, and obstacles to growth. Results: Of 812 Program Directors in the AACVPR database, 290 (36%) completed the full survey. Respondents represented somewhat larger programs compared to non-respondents (4.0 vs. 4.6 full time employees, p = 0.01), but were otherwise similar. Current enrollment levels demonstrated a median [IQ range] of 140 [75,232] patients per year and a current estimated capacity of 192 [100,300] patient per year. Respondents estimated that programs could expand services by 25% to 240 [141,380] patients annually, assuming a significant increase in patient demand and a feasible increase in resources. We estimate that if programs filled to their current capacity, national CR utilization rates would increase from 34.7% to 46.4% (95% CI, 43.9 to 48.9) of eligible US patients each year. Given feasible program expansion, utilization could increase to a maximum of 58.4% (95% CI, 55.2 to 61.6) of qualifying patients. Capacity projections based upon absolute patient numbers and national statistics revealed concordant results. The most commonly cited obstacles to increasing patient participation are shown in the figure. As seen, the majority (88%) are controllable system-related factors unrelated to patient behavior. Conclusions: Even with substantial expansion of all existing CR programs, there is currently insufficient capacity in current CR programs to meet national service needs. Solutions to this problem will likely include the creation of new CR programs, and new policies that improve reimbursement for CR and also embrace new models of CR delivery.

Background: Cardiac Rehabilitation (CR) is an effective but highly underutilized treatment for heart disease. Prior studies have demonstrated that the use of strategies such as systematic referral (as part of an order set that does not depend on physician initiative or memory, usually with an opt-out option), liaison facilitated referral (a specific staff member who discusses the program, encourages attendance, and facilitates referral), an early appointment (< 2 weeks), and telephone appointment reminder calls can all improved enrollment rates. However, it is unclear how frequently these strategies are utilized across the United States, how often CR programs monitor their participation rates, and how often quality improvement (QI) projects designed to improve participation rates are performed. Methods: We surveyed all CR program directors in the American Association of Cardiovascular and Pulmonary Rehabilitation’s (AACVPR) database. We assessed basic program features, use of systematic referral, liaison facilitated referral, early appointments, and telephone reminder calls and QI projects. We also assessed self-reported referral, enrollment, and completion rates. Results: Response rate was 36% (290/812). Non-response bias analysis showed reasonable survey representativeness. Over the past 5 years, 49% of programs measured hospital referral, 21% office/clinic referral, 71% program enrollment, and 74% program completion rates. Self-reported rates (interquartile range) were 68 [32 to 90]% for hospital referral, 35 [15 to 60]% for office/clinic referral, 70[46 to 80]% for program enrollment, and 75[62 to 82]% for program completion. Programs reported utilizing a hospital-based systematic referral, liaison facilitated referral, or inpatient CR program 64%, 68%, and 60% of the time, respectively. Early appointments (< 2 weeks) were utilized by 35% and consistent phone call appointment reminders were utilized by 50%. Over the past 5 years, the percent or programs performing QI projects were 62% for hospital referral, 42% for clinic referral, 60% for program enrollment, and 57% for program completion. Measurement of participation rates was highly correlated with performing QI projects (p < 0.0001.) Conclusions: Although programs are aware of participation rate gaps, the monitoring of participation rates is suboptimal, quality improvement initiatives are infrequent, and proven strategies for increasing patient participation are inconsistently utilized. Awareness in outpatient clinical settings is particularly low. These issues likely contribute to the national CR participation gap and may prove to be useful targets for national QI initiatives.

Introduction : Obesity is a common risk factor in cardiac rehabilitation (CR), yet many CR patients do not realize significant weight loss, despite engaging in regular exercise training while in CR. Hypothesis : We hypothesized that standard CR would demonstrate favorable body composition (BC) changes even in the absence of weight loss and sought to measure the performance characteristics of weight loss to predict BC changes. Methods : We included consecutive patients enrolled in early outpatient CR who underwent air displacement plethysmography with measurements of height, weight, and waist circumference at initiation and completion of CR. We calculated the accuracy of weight loss to identify significant improvements in BC. Results : Data from 112 patients were available for analysis; mean age 60±12 yr., 76% male, mean body mass index (BMI) 30.2±5.3 kg/m 2 . The indication for CR was myocardial infarction (n=33), percutaneous coronary intervention (n=29), coronary artery bypass or valve surgery (n=45), and heart transplant (n=5). Repeat testing occurred after a median of 81 days and 21 phase II CR sessions. There was no change in BMI (-0.53±1.3 kg/m 2 , p=0.43) and weight (-1.6±4.0 kg, p=0.51). Fat mass showed a borderline significant decrease of 2.9±3.9 kg (p=0.08). However, BC improved significantly as measured by body fat % (-2.5±3.2%, p=0.03) and waist circumference (-4.6±5.2 cm; p=0.01). There was a correlation between weight loss and fat mass loss (r=0.85, p=0.0001, positive predictive value=0.94), and % fat change (r=0.67, p=0.0001, positive predictive value=0.91). See table 1. However, the negative predictive value to detect no fat change for patients who did not lose weight was low (0.49, when assessed by % body fat loss, and 0.57, when assessed by fat mass loss). Among patients who did not lose weight, 29 (51%) had a greater than 1% body fat loss. Conclusions : The diagnostic performance of weight change to predict favorable BC changes is poor and highlights the potential utility of BC measurements in the CR setting. Table. Diagnostic Characteristics of Weight Loss as a Predictor of Improvements in Body Composition Weight Loss (kg) Body Fat % Loss ≤ 1% Fat Mass Loss (kg) > 1kg > 1% ≤ 1kg > 1kg 49 5 51 3 ≤ 1kg or gain 29 28 25 33 Sensitivity 0.63 0.67 Specificity 0.85 0.92 PPV * 0.91 0.94 NPV ** 0.49 0.57 * PPV = Positive Predictive Valve, ** NPV = Negative Predictive Value

Background: A women-based formula for calculation of age-predicted maximum heart rate [age-predicted maximum heart rate=206−(0.88×age)] was established in asymptomatic volunteer women undergoing treadmill exercise tolerance testing (ETT). We sought to perform a comparison of the performance of this women-based formula for prediction of peak heart rate to the traditional formula [220−age] and our own database-generated prediction formula in a large database of women undergoing ETT. Methods: We performed a retrospective analysis of all consecutive women who underwent symptom-limited Bruce protocol ETT at the Mayo Clinic from 1994 to 2010. Women with known cardiovascular disease or those using beta blockers, calcium channel blockers, or digitalis were excluded. Separate analyses were performed according to symptomatic status. Results: The study included 11,029 women (89.4% Caucasian) with a mean age 52±12 years; 3,632 (33%) were referred specifically for evaluation of symptoms. Age-predicted maximum heart rate calculated by the traditional formula was achieved by 49.7% of women versus 69.9% by the women-based formula with most of the underestimation observed in older women. Average absolute deviation between achieved and predicted peak heart rate (HR) was 10.85±9.18 bpm for traditional versus 11.98±9.00 for women-based formulas (dependent t =−16.64, p <0.0001). The linear regression line calculated from our population [HR=201−(0.67×age)] was closer to the women-based formula, both in terms of intercept and slope than the traditional formula. Peak HR was shown to be slightly affected (−2.5 bpm) by symptom status at referral, whereas smoking and diabetes more significantly reduced achieved peak HR. Conclusions: The women-based formula underestimated peak HR, especially in older women, but was observed to be closer in both intercept and slope to the regression line determined from our study in this large population of female patients. These sex-unique observations should be taken into account when determining adequacy and targets for ETT in women.

Background— Cardiac rehabilitation (CR) is recommended for all patients after coronary artery bypass surgery, yet little is known about the long-term mortality effects of CR in this population. Methods and Results— We performed a community-based analysis on residents of Olmsted County, Minnesota, who underwent coronary artery bypass surgery between 1996 and 2007. We assessed the association between subsequent outpatient CR attendance and long-term survival. Propensity analysis was performed. Cox proportional hazards regression was then used to assess the association between CR attendance and all-cause mortality adjusted for the propensity to attend CR. We identified 846 eligible patients (age 66±11 years, 76% men, and 96% non-Hispanic whites) who survived at least 6 months after surgery, of whom 582 (69%) attended CR. During a mean (±SD) follow-up of 9.0±3.7 years, the 10-year all-cause Kaplan-Meier mortality rate was 28% (193 deaths). Adjusted for the propensity to attend CR, participation in CR was associated with a 10-year relative risk reduction in all-cause mortality of 46% (hazard ratio, 0.54; 95% confidence interval, 0.40–0.74; P <0.001) and a 10-year absolute risk reduction of 12.7% (number needed to treat=8). There was no evidence of a differential effect of CR on mortality with respect to age (≥65 versus <65 years), sex, diabetes, or prior myocardial infarction. Conclusions— CR attendance is associated with a significant reduction in 10-year all-cause mortality after coronary artery bypass surgery. Our results strongly support national standards that recommend CR for this patient group.

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.