A Dual-Modality Home-Based Cardiac Rehabilitation Program for Adults with Cardiovascular Disease: Single-Arm Remote Clinical Trial

Background: Cardiac rehabilitation (CR) is a safe and effective intervention for individuals with cardiovascular disease (CVD). However, the majority of eligible patients do not complete CR. Growing evidence suggests that home-based CR programs are comparable in effectiveness and safety to traditional center-based programs. More research is needed to explore different ways to deliver HBCR programs to CVD patients. Objective: This study aims to assess the feasibility (primary) and preliminary impact (secondary) of a digital CR program (RecoveryPlus.Health, RPH-D) that integrates both telehealth and mHealth modalities on functional exercise capacity, resting heart rate, and quality of life among adults with cardiovascular disease (CVD). Methods: This 12-week prospective, single-arm feasibility trial used a within-subject design. We recruited adults with CVD (age 40+) from the community with a CR-eligible diagnosis (stable angina pectoris, myocardial infarction, heart failure, etc.) between May and August of 2023. All enrolled patients referred to RPH clinic in Roanoke, TX were included. The care team provided guideline-concordant CR services to study participants via two modalities: 1) a synchronous telehealth exercise training via video conferencing; and 2) an asynchronous mHealth virtual coaching App (RPH App). Baseline intake survey, electronic health record (EHR), and app log data were used to extract individual characteristics, care processes, and telehealth/mHealth engagement data. Feasibility was measured by program completion rate and CR services use. Preliminary efficacy was measured by changes in 6-minute walk test (6MWT), resting heart rate, and quality of life (SF-12) before and after the 12-week program. Paired t tests were used to examine the changes in the outcome variables pre-post intervention. Results: A total of 162 met the inclusion criteria, 75 (46.3%) consented and were enrolled. The participants’ average age was 64.24 (SD 10.30) years; 37 (49.33%) were male, and 46 (61.33%) were White. Heart failure was the most common diagnosis (49.33%). A total of 62 (82.67%) participants completed the 12-week study, 62 (82.67%) used the telehealth modality with an average of 9.63 (SD 3.33) sessions completed, and 59 (78.67%) used the mHealth modality with an average of 10.97 (SD 11.70) sessions completed. Post intervention, 50 (80.65%) participants had improved 6MWT, with an average improvement of 40.0 meters (95% CI, 25.6 to 57.1). The average SF-12 physical and mental summary scores improved by 2.7 points (95% CI, 1.1 to 4.3) and 2.2 points (95% CI, 0.1 to 4.5), respectively. There were no changes in resting heart rate and no exercise-related adverse events were reported. Conclusions:


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Intro duction
Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in the United States, with more than two million hospitalizations and 400,000 deaths due to CVD [1,2].
Cardiac rehabilitation (CR) is a grade I guideline-recommended multidisciplinary program intended to reduce the risk of subsequent cardiovascular events and improve quality of life through activities shown to improve physical, psychological, and social functioning, and ultimately reduce associated morbidity among patients with CVD [3,4].Despite strong evidence regarding its safety and efficacy [5][6][7][8], CR utilization rate remains very low, with only about 1 in 4 eligible patients enroll in CR [9,10].In addition, disparities in CR uptake with respect to sex, age, race/ethnicity, and geographic locations persist [3], contributing to the low overall CR participation rate and substantial geographic variations in participation [11].With the initiation of the Million Hearts 2022, a national program aimed at achieving a target of 70% CR participation among eligible patients by 2027 [9], the current 2,300 center-based cardiac rehabilitation (CBCR) programs in the U.S. is unlikely to meet the demand for CR [12,13].Therefore, new Home-based cardiac rehabilitation (HBCR), an alternative to traditional CBCR that allows patients to undergo rehabilitation in their own homes, are urgently needed to expand CR access [3,14].
HBCR alone or in combination (hybrid) with CBCR, has been shown to be a safe and effective option for patients eligible for CR [15][16][17], with the potential to address some of the key barriers to CR access (e.g., time and cost of transportation) [5].HBCR programs uses the same multifaceted approaches (exercise training, education, dietary guidance, and lifestyle modification) as CBCR [4,18,19], providing patients with synchronous and/or asynchronous delivery of supervised and/or remote-monitored exercise trainings and care management.
While HBCR programs have certain disadvantages compared to CBCR (e.g., lack of published clinical standards, lower exercise training intensity, and potential safety concerns for high risk patients) [5], their key advantages include: reduced enrollment delays, expanded capacity, flexible scheduling, minimal travel, and improved access for patients with limited mobility [2,20].
The unexpected disruption to CBCR access caused by the COVID-19 pandemic, inadvertently accelerated the transition of many in person CR programs to the home setting and increased the acceptability to HBCR and center-home hybrid CR programs [21].There is a need for greater engagement in safe, evidence-based CR exercise programming for patients recovering from CVD.
Among these new approaches, home-based synchronous remote CR and asynchronous virtual CR modalities, alone or in combination, have the potential to improve access by expanding provider offering and/or reduce the time and costs associated with travel to traditional CR centers [22].
The RecoveryPlus.Health This study aimed to determine whether the dual-modality RPH-D program is feasible for delivering remote CR to a nationally recruited sample, and to e its impact on patients' functional exercise capacity (cardiorespiratory endurance), resting heart rate, and quality of life.Participants

Intervention
The All clinical team members had access to the RPH remote healthcare provider web portal (HIPAA complaint) to enter, store, and view participant demographic and clinical information, create fitness assessments, write and update a patient's exercise prescription, and generate reports.The clinicians were trained to use patient feedback along with data derived from heart rate monitors to assess exercise intensity, appropriateness, and adherence to the prescribed exercise program, and, importantly, make adjustments to better personalize the care plan for each patient.The RPH remote CR platform also provided real-time, automated alerts that were sent to the care team for any symptoms or reports of out-of-range heart rate reading to facilitate immediate attention/evaluation to determine the severity of a symptom and whether/which course of action is required for follow up.In these events, participants were instructed to stop exercising immediately and report any cardiacrelated symptoms to their clinician at any time, during or outside of exercise sessions.The clinical care team received and responded to alerts 24 hours a day, 7 days per week.

Outcomes and Measures
The main variables of interest were feasibility and efficacy.

Sample size calculation
Power calculation was based on the primary efficacy measure: six-minute walk test (6MWT).
At 5% level of significance, to achieve 85% power in detecting a small to moderate difference of 35 m for the 6MWT before and after the RPH-D program, a sample size of 75 participants was required [24,27].To account for an estimated 25% attrition rate, a total sample of 100 was set as the enrollment target.

Statistical Analysis
Standard descriptive statistics were used to describe the study sample and compare them by study completion status.Two-sample t test were used for continuous variables and Fisher's Exact Test were used for categorial variables.To explore the preliminary impact of the RPH-D program on the outcome measures, paired t tests were used to examine whether there were any within-subject changes post-intervention.To quantify the uncertainty surrounding the point estimates of effect sizes, 95% confidence intervals (CI) were calculated using non-parametric bootstrapping with 5000 repetitions [28].Statistical analysis was performed in Stata 17 BE (Stata Corp., College Station, TX).

Results
Of the 272 individuals screened for eligibility, a total of 162 individuals from 29 states met the study eligibility criteria and 75 (46%) consented to the study and were enrolled in the RPH-D program.Thirteen participants withdrew from the study and 62 (83%) were included in the analysis (Figure 1).     of participants completed all 12 sessions.59 out of 75 (79%) used the mHealth modality (10.97 [11.70] sessions) and 32 out of 62 (52%) completed all 12 sessions.Among those who completed the study, all participants used the telehealth modality and all but three participants used the mHealth modality.Participants completed an average of 654.1 minutes of telehealth sessions and 421.0 minutes of mHealth sessions (Table 2).A total of 12 participants visited the emergency room (15 visits total) and none were related to the RPH-D program.3).Overall, participants who completed the intervention had an average improvement in 6-minute walk test performance of 40.0 meters (95% CI, 25.6 to 57.1).The average SF-12 Physical and Mental Component Summary scores improved by 2.7 (95% CI, 1.1 to 4.3) and 2.2 (95% CI, 0.1 to 4.5) points, respectively.There was a small nonsignificant improvement in average resting heart rates (-1.1, 95% CI: -3.4,1.1).

Discussion
In this remote clinical study, the RPH-D digital home-based CR program that integrated a synchronous telehealth and an asynchronous mHealth modalities was tested among a group of nationally recruited individuals with cardiovascular disease.Screening, recruitment, and engagement outcomes showed that while enrollment yield was modest, the great majority of consented individuals were able to complete the program.Adherence to both modalities was high, although there were substantial variations in adherence to the mHealth exercise sessions.Overall, the program was feasible and efficacious in improving functional exercise capacity and quality of life.
Home-based versus center-based cardiac rehabilitation continues to receive much attention, with a recent Cochrane review identifying 24 completed trials and at least 14 more registered.While the extent evidence suggests that these two delivery approaches showed comparable effects on total morality and exercise capacity up to 12 months post intervention, with no significant differences in health-related quality of life for up to 24 months [12], evidence regarding the delivery modality for HBCR is less clear.A recent review of asynchronous and synchronous delivery models for HBCR showed that while most studies of HBCR tested asynchronous approaches prior to 2016, a growing number of HBCR trials started to incorporate synchronous approaches [14].The findings of this study add to the growing evidence base supporting the feasibility of a concurrent dual-modality remote CR for individuals with CVD.For example, a study in New Zealand among predominantly male patients with CHD found that 82.9% (68/82) of those assigned to the remote CR program completed the 12-week program.Two smaller studies in the U.S. reported slightly lower completion rates.Misra et al. tested a digitally delivered remote CR program among 12 patients underwent catheter ablation of AF in Charlotte, NC [29].92% (11/12) were able to complete the 12-week program, with an average of 2.9 exercise sessions per week.Giggins et al. reported a completion rate of 72.7% (8/11) for an 8-week web-based remote CR program among patients with CHD [30].Taken together, these findings support the feasibility of HBCR programs for individuals with CVD.
The broad geographic reach (29 states) of the RPH-D program conducted from a single clinic shows the promise of digital technology-enabled remote CR programs.As geographic disparities in access to traditional center-based CR has been highlighted as one of the main barriers to CR participation [3,31], asynchronous home-based CR programs like the RPH-D program provides greater flexibility for CVD patients.The findings indicate that the great majority of eligible participants initiated CR with high completion rates.The availability of the asynchronous mHealth modality may help narrowing the digital divide among patients from rural and remote areas [32].
Participation rate (of 50%) did not differ among participants based on sex and race/ethnicity, suggesting that the program may offer women and minority patients an equitable option for HBCR access.
Findings from this study are also in line with those from multiple systematic reviews concluding that eHealth delivery of cardiac rehabilitation increases patient physical activity and compliance [14,[33][34][35].As suggested by a recent review of virtual solutions for CR [20], the use of multiple devices for monitoring and communication with their healthcare team, program personalization, and continuous feedback for users all contributed to the program compliance and feasibility found in this study.This review of 19 different studies of virtual cardiac rehabilitation programs noted, as did ours, no intervention-related adverse events, suggesting that remote CR is generally safe.
The current study contributes to the literature in several ways.To the best of our knowledge, this is the first study that tested a concurrent telehealth and mHealth dual-modality HBCR program in a group of age and sex diverse adults in the U.S.An Australian-based randomized controlled trial with 24-week (12+12) sequential dual modality HBCR program is currently being tested [36].It was designed to be pragmatic, with care team members providing remote CR service using existing clinical procedures and electronic medical records system for workflow management.Hybrid, remote, and digitally supported CR services appear to be a safe and effective delivery approach for secondary prevention of CVD with growing evidence [4,[37][38][39][40].In addition, the encouraging uptake of remote CR services by women and minority patients may offer new ways to reduce disparities in CR care [41], with the potential to greatly increase the number of CVD patients engaging in evidence-based CR, an intervention shown to positively impact the health, fitness and quality of life outcomes for these patients [7,42,43].Our data demonstrates that CVD patients will sustain engagement with a platform like RPH remote CR that combines synchronous 1:1 telerehabilitation sessions with an EP with asynchronous exercise sessions longer than they would be traditional in person CR.Additionally, the on demand exercise feature of the program provides an engaging physical activity option outside of the one-on-one teleconferencing sessions, a promising solution to scheduling and scalability challenges of traditional in person CR programs.Finally, it is encouraging that this study enrolled a gender, culturally, and geographically diverse patient population, all of which has long been recognized as being underserved by CR services [44][45][46].

Limitations
Several limitations should be considered when interpreting the findings.This single-arm remote clinical trial did not include a control group, so we cannot rule out that the changes in the patient outcome measures may be due to factors other than the RPH-D program.This design choice was based on clinical and ethical reasons: CR is a well-established clinical approach to manage CVD, thus a randomized attention controlled/wait-listed trial could have required not offering/delaying the active intervention for half of eligible patients.Even a randomized controlled trial with an active CBCR arm would have required some patients to access center-based CR, which may not be readily available for this patient population.Second, study participants came from a national convenience sample with heterogeneous CR-eligible diagnoses and the sample size was modest.Therefore, the findings should be replicated in larger national studies that would allow for subgroup analyses (e.g., by referring diagnoses, age, or sex) to help inform clinical practice.Third, the 12-week follow-up period was limited and cannot offer evidence regarding longer term adherence and outcomes.In addition, the participation rate for the mHealth modality was limited, as some participants experienced challenges with using the iPad with wireless monitors due to limited digital literacy.Finally, relying on two primary recruitment channels (through community partner referral and online advertisement) contributed to the under recruitment of the study.Future studies should broaden the referral network to include primary and specialty care, and include an economic evaluation component to generate evidence regarding the value for payers [47].Devices that enable coverage beyond traditional WiFi technology (such as those based on 5G mobile phone network or satellite network) can further reduce geographic barriers to HBCR.These limitations notwithstanding, this is the first U.S. study to test an innovative dual-modality remote CR program that combined synchronous and asynchronous approaches to deliver a fully remote home-based CR program.

Conclusions
The results of this study show that a dual-modality home-based CR program can be a feasible option to improve access to home-based CR for improving functional exercise capacity after acute CVD.Future research using randomized controlled design (e.g. a preference-based RCT) is needed to test the RPH-D CR program in a larger, more diverse pool of patients.If the long-term impact of this program can be confirmed in a multi-center randomized controlled study, a stronger case can be made to implement HBCR programs in health care systems to increase the uptake of CR and bridge the gap between evidence and practice in secondary prevention of CVD.
® digital HBCR program (RPH-D) is an innovative program that combines two delivery modalities: a synchronous telehealth modality delivered via video conferencing by an interdisciplinary care team and an asynchronous mHealth modality delivered via a digital app (RPH App) for individualized exercise therapy.The RPH-D program was developed based on the American Heart Association CR guidelinefor delivering tailored, evidence-based CR to remotely and on demand.
This is prospective single-arm remote clinical trial used a within-subject design.The study protocol was approved by the Advarra IRB (Pro00070335) and written informed consent was obtained from all participants.Between May 1 st and November 30 th , 2023, a dedicated recruitment website was established to facilitate the sharing of study information for recruitment through two primary channels: referrals from cardiology providers in the Dallas-Fort Worth area, and through a collaboration with The Mended Hearts, Inc., a national and community-based nonprofit cardiovascular patient support organization.The community partners sent emails to their patients/members prompting potential participants to visit the study website.Potential participants were screened for eligibility criteria via a secure online questionnaire.Patients who passed the initial screeningwere contacted by the study coordinator by phone to verify eligibility and finalize enrollment.
RecoveryPlus.Health Digital CR Program (RPH-D) The RPH-D program for patients recovering from a CVD event leverages two weekly concurrent remote modalities to engage the study participants: (1) synchronous (telehealth) coaching sessions conducted by an exercise physiologist via Zoom for Healthcare; and (2) asynchronous (mHealth) exercise sessions via the RPH app.The telehealth sessions focused on the following core CR services: patient assessment, exercise training, care management, lifestyle counseling, and remote monitoring.The study iPads were preloaded with the RecoveryPlus.Health App, which offers a library of on-demand exercise videos with varying degrees of difficulties.Wireless heart rate and blood pressure monitors were connected to the iPad via Bluetooth to enable real-time monitoring of patient vital signs and feedback (e.g., patient rated difficulty for each prescribed exercise) and tailor individual patient regimens regularly for safety and fine-tuning the exercise therapy.During the appbased exercise sessions, Participants rated the perceived level of difficulty (exertion) of each exercise on a 1-10 scale.If a patient chooses to skip an exercise or exit a session prior to completing the prescribed exercises, reasons were documented via the app (Multimedia Appendix 1).
Feasibility was measured by program initiation (the proportion of enrolled patients who completed all baseline assessments and completed the initial virtual session with an EP) and participation (the proportion of enrolled patients who completed at least 50% or more of prescribed sessions).Feasibility data were captured via the HIPAA compliant, encrypted, RPH electronic health records.Efficacy was measured by: six-minute walk test (6MWT), resting heart rate, and quality of life.These measures were assessed by the study exercise physiologist and recorded on the RPH EHR platform.The 6MWT was measured via the 6WT app, an iOS application validated in 330 volunteers (age range: 16-91 years)[23].Participants were instructed to walk on a flat, hard surface outside of their homes in a period of six minutes.The 6-minute walk test is a widely used and well documented measure of aerobic exercise capacity used to indicate change in fitness[24].Resting heart rate is positively associated with mortality and is known to decline with regular exercise[25].Quality of life was measured by the 12-Item Short-Form Health Survey (SF-12™ Version 2), a validated and commonly used measure of perceived quality of life and functional health among patients with CVD[26].Individual characteristics included basic socio-demographic variables collected at baseline (age, sex, race/ethnicity, comorbidities, and referring diagnosis).

Figure 1 .
Figure 1.CONSORT flow diagram for patient enrollment and follow-up artery bypass grafting; CHF=chronic heart failure; AMI=acute myocardial infarction; PCI=percutaneous coronary intervention A total of 62 out of 75 (83%) participants completed the 12-week study.50 out of 62 (81%) completed at least 50% of CR sessions.All participants were prescribed 12 one-on-one videoconferencing (telehealth) sessions (55-minute per week, 660 minutes total) and 12 app-based exercise (mHealth) sessions (27.8-minute per week, 334 minutes total) over 12 weeks.A total of 62 out of 75 (83%) participants used the telehealth modality (9.63 [3.33] sessions) and 34 of 62 (55%) deviation; Q1=25 th percentile; Q3=75 th percentile Three outcome measures were used to examine the impact of the intervention before and after the 12-week intervention (Table were included if they were aged 45 or older; had stable CVD and under medical management; received referral to CR from a provider within 60 days; able to walk unassisted; deemed stable with low to moderate risk of cardiac event; and with a CR eligible diagnosis in prior 12 months as defined by Medicare Part B (stable angina pectoris, myocardial infarction, stable heart failure, coronary artery bypass graft surgery, etc.).Participants were excluded if they were unable to read and speak in English, had a body mass index (BMI) of greater than 40; had hospitalization or significant decline in health; had physical or mental health limitations that prohibit participation in exercise activities; cannot use a tablet computer; lack of access to WiFi; or had severe hearing and/or vision impairment.

Table 1
. displays the baseline participants' individual characteristics for the overall sample and by participation rate (less than or greater than 50%).Study participants had a mean age of 64.6 (SD=10.0;range:45-85 years) and 38 (51%) were female (Table1 Participants who completed 50% or more sessions were older and more likely to have PCI as the referring diagnosis.With the exception of age and BMI, there were no significant differences in the characteristics of the participants who completed the study versus those who did not (supplemental Table1 ). Non-Hispanic White participants made up the majority of the sample at 46 (61%), followed by 8 (11%) Black Americans, 5(7%) Hispanics, and 16(21%) other or missing race/ethnicity.The top five referring diagnosis/procedures were: chronic heart failure (37, 50%), coronary artery bypass grafting (9, 15%), valvular surgery (9, 15%), acute myocardial infarction (6, 10%), and percutaneous coronary intervention (6, 10%). ).

Table 2 .
Participant engagement with the two modalities of remote cardiac rehabilitation (n=62)