Cardiac Rehabilitation — Challenges, Advances, and the Road Ahead

Authors, Journal, Affiliations, Type, DOI

• Randal J. Thomas, M.D.
• Division of Preventive Cardiology, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
• New England Journal of Medicine, 2024;390(9):830-841
• Review article
• DOI: 10.1056/NEJMra2302291

Overview

Cardiac rehabilitation (CR) is a multidisciplinary, 36-session, 12-week secondary prevention program encompassing exercise training, nutritional counseling, psychosocial support, and guideline-directed risk factor management. Despite robust evidence of benefit — including 1–2% mortality reduction per session attended and NNT=12 for preventing one hospital readmission — only ~24% of eligible US patients participate in CR, representing one of the largest quality gaps in cardiovascular medicine. Participation disparities are most pronounced among women, racial/ethnic minorities, elderly patients, and those with low socioeconomic status. Home-based CR provides equivalent short-term outcomes and better initiation rates than center-based programs, and future directions include wearable technologies, prehabilitation, and expanded eligibility to AF, HFpEF, and cancer+CVD populations.

Keywords

Cardiac rehabilitation, secondary prevention, exercise training, cardiovascular disease, home-based rehabilitation, participation gap, health disparities

Key Takeaways

History

• CR began in the mid-20th century as bed rest was replaced by progressive physical activity after MI; Levine and Lown (1952) introduced armchair exercise; Hellerstein and Ford extended CR to the outpatient setting in the 1950s–60s
• Safety of outpatient CR was established by Haskell (1978): 1 fatal event per 100,000 patient-hours
• Oldridge et al. 1988 meta-analysis (10 RCTs, 4,347 patients): 25% reduction in cardiovascular mortality with CR
• CMS began covering outpatient CR and guidelines were published in 1995
• Current safety data: 1 cardiac arrest per 1.3 million patient-hours of CR exercise

Program Structure

• Eligible patients: post-MI, PCI, CABG, heart-valve surgery, heart transplantation, stable angina, HFrEF, symptomatic peripheral artery disease (ACC/AHA Class I or IIa indications)
• Prompt enrollment critical: participation is 1% lower for every 1-day delay; 67% greater exercise capacity improvement when enrolled within 15 days vs ≥30 days post-discharge
• 36 sessions × 1 hour over 12 weeks; individualized treatment plan reviewed every 30 days
• Four core domains: (1) exercise (aerobic, resistance, flexibility, balance); (2) nutritional counseling; (3) psychosocial support; (4) cardiovascular risk factor control + GDMT adherence
• Multidisciplinary team: physicians, nurses, exercise physiologists, dietitians, social workers, psychologists
• ECG monitoring used for high-risk arrhythmias but does not improve safety outcomes

Benefits

• Functional capacity: improved exercise capacity sources/crp-nejm-2024
• Psychological health: reduced anxiety and depression
• GDMT adherence: improved medication adherence
• Risk factor control: improved BP, lipid, glucose, weight targets
• Hospital readmission: NNT=12 to prevent 1 readmission at 12 months sources/crp-nejm-2024
• Mortality (observational): 1–2% reduction per session attended (dose-response); NNT=34 at 1 year, NNT=22 at 5 years after PCI
• Cost savings: ~$2,920 CAD/year savings per CR participant vs non-referred; ICER $1,065–$71,755 per QALY
• Contradiction: Cochrane systematic review of RCTs shows little or no effect on all-cause mortality; benefit clearest in large observational studies — may reflect improved usual care in the contemporary era or healthy-participant bias

Participation Gap

• Only 24% of eligible US patients participated in CR in 2020
• Only 24% enrolled within 21 days of qualifying event; only 27% completed a full course
• Trends: CABG participation improved from 31% (1997) to 55% (2020); post-MI with PCI from 21% to 33%; post-MI without revascularization fell from 11% to 7%
• Estimated program capacity sufficient for only 37% of eligible patients nationally
• Disparities by group:
  • Women: 18.9%
  • Age >85: 9.8%
  • Non-Hispanic Black: 13.6%
  • Hispanic: 13.2%
  • Dual Medicare-Medicaid: 6.9%
  • Geographic: 39% (West North Central) vs 20% (East/West South Central, Middle Atlantic, Pacific)
• Strategies to bridge gap: automatic referral systems, patient navigators → boost participation from 30% to 74%; financial incentives (Medicaid: 2× completion rate with moderate financial incentives); removal of cost-sharing adds average 6 sessions (theoretical 6–12% mortality reduction)

Home-Based CR

• First studied by DeBusk et al. 1994; uses same clinical components as center-based CR but delivered remotely (telephone, video, synchronous or asynchronous)
• AACVPR–ACC–AHA 2019 scientific statement: short-term outcomes equivalent to center-based CR; recommended as reasonable alternative for those unable to attend center
• Higher adherence and initiation rates: 43% vs 13% for center-based CR
• VA observational study: 36% lower mortality in home-based CR vs no CR participation
• Southern California observational study: similar secondary prevention target attainment + lower 12-month hospital readmission vs center-based
• Cost-effective vs no CR, but comparison with center-based unclear
• Future of CMS coverage for home-based CR uncertain after COVID-19 public health emergency ended

Future Directions

• Wearable technologies, physiological monitors, communication devices to deliver CR anywhere
• Expanded eligibility: AF, HFpEF, cancer+CVD, congenital heart disease
• Prehabilitation: CR before a procedure (not only after)
• Goal: shift from high-value/low-utilization to high-value/high-utilization

Limitations of the Document

• Review article — no primary data; relies on heterogeneous observational studies and older RCTs for mortality benefit
• Cochrane meta-analysis (primary evidence base for RCT mortality) shows neutral all-cause mortality — review frames this cautiously but the disconnect with observational data creates uncertainty
• US-centric perspectives on CMS coverage and participation statistics; may not apply internationally
• Home-based CR evidence largely from observational studies; limited RCT data for long-term outcomes, women, minority groups, and elderly

Key Concepts Mentioned

• concepts/Cardiac-Rehabilitation — primary subject; program structure, evidence, and access gaps
• concepts/Secondary-Prevention-CVD — overarching framework CR operates within
• concepts/Exercise-in-HCM — tangentially relevant; CR exercise principles

Key Entities Mentioned

• Mayo Clinic — author's institution; key CR research center
• American College of Cardiology (ACC) — guideline source for CR indications
• American Heart Association (AHA) — guideline source and Million Hearts Collaborative
• American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR) — certifying body and scientific statement author
• Centers for Medicare and Medicaid Services (CMS) — coverage determinations for CR
• Million Hearts Cardiac Rehabilitation Collaborative — multi-stakeholder initiative targeting 70% national participation
• Joint Commission — Comprehensive Cardiac Center Certification includes CR as key component

Wiki Pages Updated

• wiki/sources/crp-nejm-2024.md — created (this file)
• wiki/concepts/Cardiac-Rehabilitation.md — created
• wiki/sourceindex.md — updated
• wiki/wikiindex.md — updated