Squires, Ray W.

Introduction: Cardiac rehabilitation (CR) is associated with improvements in exercise capacity (peak oxygen uptake (VO 2 peak)); however, 23% of CR patients do not improve VO 2 peak following CR. CR adherence (i.e. number of CR sessions attended) has been proposed to play an important role in VO 2 peak improvement following CR, but has not been investigated. Identifying clinical predictors of VO 2 peak improvement are critical as the degree of VO 2 peak improvement is associated with improved long-term outcomes in these patients. Purpose: To determine if clinical characteristics and number of CR sessions attended were predictive of patients who exhibited improvement in VO 2 peak following CR. Methods: Using the Rochester Epidemiology Project records-linkage system, we identified all consecutive patients >18 years old from Olmsted County, Minnesota who underwent cardiopulmonary exercise testing prior to and following CR from 1999 to 2017. Regression models were created to assess clinical predictors of VO 2 peak improvement (>0% baseline) following CR. Results: The analysis included 804 patients (75% men) with a mean age of 60.7±12.4 years. Of the 804 patients, 609 (76%) patients exhibited VO 2 peak improvement following CR. Significant univariate predictors of VO 2 peak improvement included younger age (OR: 0.99, 95% CI: 0.97-1.00), lower pre-CR VO 2 peak (OR: 0.97, 95% CI: 0.94-0.99), history of peripheral artery disease (OR: 0.48, 95% CI: 0.32-0.73), and smoking (OR: 0.63, 95% CI: 0.45-0.90). Significant independent predictors of VO 2 peak improvement from a multivariate analysis included younger age (OR: 0.98, 95% CI: 0.96-1.00), number of CR sessions (OR: 1.02, 95% CI: 1.01-1.03), lower pre-CR VO 2 peak (OR: 0.94, 95% CI: 0.91-0.96), history of peripheral artery disease (OR: 0.42, 95% CI: 0.27-0.66), and smoking (OR: 0.56, 95% CI: 0.39-0.82). Conclusions: These findings demonstrate the importance of CR adherence and individual clinical characteristics in influencing VO 2 peak improvement following CR in patients with CVD. These findings may influence the clinical practice by providing specific clinical characteristics to account for when personalizing the CR treatment plan to maximize positive outcomes.

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: We conducted this study to assess the safety of symptom-limited cardiopulmonary exercise testing (CPX) in patients with varying severity of aortic stenosis (AS). We hypothesized that exercise testing would be safe, as defined by a rates for all-cause death of <0.01% and rate of nonfatal major cardiovascular (CV) events <0.1% within 24 hours of CPX. Secondary purpose of this study was to determine the frequency of complications during CPX. Methods: This cohort study was carried out with 308 consecutive patients with varying degree of AS (as determined by standard echocardiographic criteria) with no or equivocal symptoms who were referred for clinically indicated cardiopulmonary testing between 1994 and 2009. We did not include patients with pending or completed heart transplant, or ventricular assist device implantation. These patients underwent standard symptom limited CPX, and continuous monitoring of heart rate, blood pressure, and electrocardiogram was performed. Complications recorded included death, non-fatal major CV events (cardiac arrest, symptomatic and sustained ventricular or atrial tachycardia, and syncope), and minor events such as hypotension, non-sustained atrial and ventricular arrhythmias, positive exercise ECG and anginal pain. Results: The mean age of patients was 66 ± 14 years, and 252 (82%) were males. The number of patients with mild, moderate and severe AS were 44 (14%), 138 (49%), and 126 (41%) respectively. No death or major CV event occurred during or within 24 hours of CPX. Eleven patients developed supraventricular arrhythmias without compromising hemodynamic status, and one had asymptomatic non-sustained ventricular tachycardia. Detailed description of complications is presented in the Table 1 . Conclusion: Our results show that symptom-limited CPX is safe among AS patients with no or equivocal symptoms based on no deaths or major CV events in our cohort. Minor complications occurred in 110 patients (36%). Table 1 Mild AS (n=44) Moderate AS (n=138) Severe AS (n=126) Age 61.7 ± 15.3 66.5 ± 13.86 67.89 ± 12.74 Males 36 (81%) 128 (83%) 96 (85%) Test protocol O2 protocol 39 (86%) 123 (89%) 104 (82%) Other 5 15 22 Reason for termination Symptom-limited 41 (93%) 114 (82%) 96 (76%) Other 3 24 30 Chest pain None 41 (93%) 122 (88%) 117 (93%) Non-cardiac 0 2 0 Non-anginal 0 2 0 Anginal 2 14 9 Treadmill ECG interpretation Negative 27 (61%) 67 (49%) 45 (37%) Non-diagnostic 14 48 58 Positive 3 23 23 Ventricular arrhythmia None 42 (95%) 134 (97%) 122 (97%) 3-5 beats VT 2 3 4 NSVT 0 1 0 Supraventricular arrhythmia None 42 (95%) 135 (97%) 120 (95%) SVT ≤ 30 sec 2 3 4 SVT > 30 sec 0 0 1 Afib 0 0 1 BP response Normal 41 (93%) 117 (85%) 93 (74%) Hypotensive 3 21 33 AS = Aortic Stenosis, ECG = Electrocardiogram, VT = Ventricular tachycardia, NSVT = Non-sustained ventricular tachycardia, SVT = Supraventricular tachycardia, Afib = Atrial fibrillation, BP = Blood pressure

Background: Randomized controlled trials and meta-analyses have demonstrated the benefits of cardiac rehabilitation (CR) in patients with acute myocardial infarction (AMI). Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of AMI. However, the benefit of CR has not been well studied in patients with SCAD. Purpose: Our objective was to compare the psychosocial and physiological characteristics and outcomes of CR in SCAD patients who participated in CR compared to those who did not. Methods: We performed a retrospective descriptive analysis of patients with angiographically confirmed SCAD enrolled in the Mayo Clinic SCAD Registry from January 2010 through December 2014 who had completed questionnaires (n=354). Demographics, clinical characteristics, Generalized Anxiety Disorder 7-Item Scale (GAD-7), Patient Health Questionnaire-9 (depression measure; PHQ-9), and details about participants’ CR participation and experience were collected via medical record review and questionnaires. Univariate analyses were performed to determine the differences between baseline characteristics and outcomes according to CR participation status. Results: Mean age of participants at time of SCAD was 46 ± 10 years; 95% were female. Seventy-six percent of participants participated in at least one CR session, and those users averaged 18 ± 12 sessions. A majority of CR participants reported physical and emotional benefits (82% and 75%, respectively). Of those who did not participate in CR, the primary reason was because their healthcare provider did not recommend CR (67%). Other reasons included inadequate transportation (12%), no insurance coverage (8%), cost (2%), no energy (2%), and being too ill (2%). On comparative analyses, CR participants had higher mean GAD-7 scores (4.9 vs. 3.9; p=0.03) and were more likely to increase their amount of exercise (p<0.01). Conclusions: Despite the well-known benefits of CR, in this international registry, only 76% of SCAD patients participated. Lack of recommendation for CR by a health care provider was the primary reason patients did not participate. The majority of patients reported benefits from CR. Higher GAD-7 scores were associated with CR participation, an interesting result requiring further evaluation in a larger or prospective cohort.

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

Body mass index (BMI) does not differentiate fat and lean mass or the distribution of adipose tissue. The purpose of this study was to examine the prevalence of metabolic syndrome (MetS) among patients entering outpatient cardiac rehabilitation (CR) across fat mass index (FMI) categories compared with BMI. This retrospective cross-sectional study evaluated dual-energy x-ray absorptiometry in 483 CR patients from 1 January 2014, through 31 December 2017. Clinical data were extracted from the electronic health record. Patients were grouped by FMI and BMI categories. Mean (SD) age of patients was 64.3 (14) years. The normal FMI category had 15 patients; excess fat, 74; and obese, 384. In contrast, 93, 174, and 216 were in the normal, overweight, and obese BMI categories, respectively. Prevalence of MetS was 0 (0%) in normal, 5 (1%) in excess fat, and 167 (54%) in obese FMI, with 97% in the obese category. MetS prevalence was 4 patients (0.8%) in normal, 39 (8%) in overweight, and 129 (27%) in obese BMI categories, with 75% of MetS in the obese category. FMI more accurately classified CR patients with metabolically abnormal fat (p < 0.001). FMI is a more sensitive index than BMI for metabolically abnormal fat of outpatient CR patients.

The measurement of peak oxygen uptake (VO2peak) is an important metric for evaluating cardiac transplantation (HTx) eligibility. However, it is unclear which factors (e.g., recipient demographics, clinical parameters, cardiac rehabilitation (CR) participation) influence VO2peak following HTx. Consecutive HTx patients with cardiopulmonary exercise testing (CPET) between 2007–2016 were included. VO2peak was measured from CPET standard protocol. Regression analyses determined predictors of the highest post-HTx VO2peak (i.e., quartile 4: VO2peak > 20.1 mL/kg/min). One hundred-forty HTx patients (women: n = 41 (29%), age: 52 ± 12 years, body mass index (BMI): 27 ± 5 kg/m2) were included. History of diabetes (Odds Ratio (OR): 0.17, 95% Confidence Interval (CI): 0.04–0.77, p = 0.021), history of dyslipidemia (OR: 0.42, 95% CI: 0.19–0.93, p = 0.032), BMI (OR: 0.90, 95% CI: 0.82–0.99, p = 0.022), hemoglobin (OR: 1.29, 95% CI: 1.04–1.61, p = 0.020), white blood cell count (OR: 0.81, 95% CI: 0.66–0.98, p = 0.033), CR exercise sessions (OR: 1.10, 95% CI: 1.04–1.15, p < 0.001), and pre-HTx VO2peak (OR: 1.17, 95% CI: 1.07–1.29, p = 0.001) were significant predictors. Multivariate analysis showed CR exercise sessions (OR: 1.10, 95% CI: 1.03–1.16, p = 0.002), and pre-HTx VO2peak (OR: 1.16, 95% CI: 1.04–1.30, p = 0.007) were independently predictive of higher post-HTx VO2peak. Pre-HTx VO2peak and CR exercise sessions are predictive of a greater VO2peak following HTx. These data highlight the importance of CR exercise session attendance and pre-HTx fitness in predicting VO2peak post-HTx.