Comprehensive Cardiac Rehabilitation for Patients With Myocardial Infarction　― Impact on Prognosis in Patients With Low Exercise Capacity ―

In Japan, the early phase mortality rate for acute myocardial infarction (AMI) has been reported to be 5–8%; however, gradual improvement in mortality has occurred since the development of primary percutaneous intervention and medical therapy.^1,2 Conversely, long-term prognosis for patients with AMI remains poor. The Japanese Registry of Acute Myocardial Infarction Diagnosed by Universal Definition (J-MINUET) study revealed that the incidence of the composite endpoint (death, non-fatal myocardial infarction [MI], non-fatal stroke, cardiac failure, and revascularization for unstable angina) from 1 month to 3 years after MI onset was 19.8% in patients with ST-elevation myocardial infarction (STEMI), 33.6% in patients with non-STEMI (NSTEMI) with elevated creatine phosphokinase (CPK) levels, and 34.2% in patients with NSTEMI without elevated CPK.³ This finding suggests that those with NSTEMI have a higher coronary risk than patients with STEMI, which leads to more advanced coronary atherosclerosis.² In addition, ischemic heart disease is the most common cause of acute decompensated heart failure in Japan at 31%,⁴ which suggests that patients who survive acute treatment for MI may be aging and develop heart failure. In addition to advanced age, these patients are often found to have comorbidities such as hypertension, diabetes, dyslipidemia, and atrial fibrillation. These findings indicate that comprehensive intervention, including the management of coronary risk factors, is important for improving the long-term prognosis of patients with MI.

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Comprehensive cardiac rehabilitation (CR) aims to improve exercise capacity and long-term prognosis, prevent the recurrence of cardiac disease and rehospitalization, and ameliorate quality of life, depression, and frailty.⁵ Components of a CR program include exercise training with appropriate intensity, patient education, counseling, and disease management based on medical evaluation. CR is a long-term intervention program for ‘self-support’, starting in the acute phase soon after the onset of cardiac disease, continuing through the early recovery phase during hospitalization, supporting patients in the late recovery phase after discharge back to their place of living, and enabling lifelong disease management during the maintenance phase. In patients with AMI, the prognostic benefits of CR have been reported. May et al comprehensively analyzed large comparative trials of CR and reported a potential 21–32% reduction in mortality.⁶ O’Connor et al investigated the effect of exercise therapy on 4,500 patients with AMI over a 3-year period and observed a 20% mortality reduction (Figure).⁷ Moreover, in a meta-analysis of 34 reports in patients with MI, Taylor et al reported that CR reduced all-cause mortality by 26%, cardiac mortality by 36%, and recurrent AMI by 47%.⁸ Conversely, low exercise tolerance is often reported to be a predictor of poor prognosis in heart failure patients.⁹ Similarly, in AMI, all-cause mortality, recurrent MI, and rehospitalization for heart failure were reported to be significantly more common in patients with low exercise capacity.¹⁰ Whether comprehensive CR improves long-term prognosis in patients after MI who have low exercise tolerance is unclear.

Figure.

Comprehensive cardiac rehabilitation (CR) for patients with acute myocardial infarction (AMI). HF, heart failure; MACE, major adverse cardiovascular events; QOL, quality of life; UAP, unstable angina pectoris.

In this issue of the Journal, Hiruma et al report on a retrospective single-center observational study of the effect of comprehensive CR in patients with AMI, with a focus on those with reduced exercise capacity.¹¹ In this study, the mean (±SD) follow-up period was 6.11±4.0 years, approximately 60% of patients with AMI had reduced exercise capacity, and comprehensive CR significantly reduced major adverse cardiovascular events (MACE) regardless of exercise capacity. Killip class ≥II, diuretics at discharge, and a lack of comprehensive CR participation were specified as independent predictors of MACE following AMI. Furthermore, improvement in peak V˙O₂ after completion of the CR program was not associated with MACE. The authors speculate that the reason for the long-term improvement in prognosis regardless of exercise tolerance at the start of CR is that the effects of CR go beyond short-term improvements in exercise tolerance; that is, the comprehensive interventions of the CR component, such as patient education, counseling, and disease management, contribute to improved outcomes.¹¹ Sjölin et al reported that participation in CR after AMI was associated with a higher success rate in smoking cessation, reduced triglyceride concentrations, and increased daily physical activity at 1 year.¹² As mentioned above, one must consider that patients with NSTEMI have a poorer prognosis than those with STEMI, which is influenced by the presence of more coronary risk factors,^2,3 and ischemic heart disease is the most common cause of acute heart failure in Japan.⁴ The fact that long-term prognosis was improved by participation in CR, even in patients with low exercise tolerance or poor improvement in exercise capacity at completion of CR, is crucial because it indicates the potential contribution of CR to lifelong risk management.

In contrast, the outpatient CR participation rate in the study of Hiruma et al was 70%, which is considerably higher than previously reported.¹¹ Kataoka et al reported on trends in CR participation in Japan.¹³ In that study, between 2013 and 2019, the number of inpatient CR participants increased, but the growth in the number of outpatients participating in CR hardly increased in comparison. Only 7.9% of patients participated in the outpatient CR program, compared with a 44% inpatient participation rate in those with acute coronary syndrome.¹³ In recent years, telecardiac rehabilitation has shown promise as a way to improve participation rates, with its effectiveness and safety reported in patients with heart failure,¹⁴ but further evidence is required.

Acknowledgment

The author thanks Editage (www.editage.com) for English language editing.

Disclosure

The author has no conflicts of interest relevant to the content of this article.

References

• 1.   Miyachi H, Takagi A, Miyauchi K, Yamasaki M, Tanaka H, Yoshikawa M, et al. Current characteristics and management of ST elevation and non-ST elevation myocardial infarction in the Tokyo metropolitan area: From the Tokyo CCU network registered cohort. Heart Vessels 2016; 31: 1740–1751.
• 2.   Ishihara M, Fujino M, Ogawa H, Yasuda S, Noguchi T, Nakao K, et al. Clinical presentation, management and outcome of Japanese patients with acute myocardial infarction in the troponin era: Japanese Registry of Acute Myocardial Infarction Diagnosed by Universal Definition (J-MINUET). Circ J 2015; 79: 1255–1262.
• 3.   Ishihara M, Nakao K, Ozaki Y, Kimura K, Ako J, Noguchi T, et al. Long-term outcomes of non-ST-elevation myocardial infarction without creatine kinase elevation: The J-MINUET study. Circ J 2017; 81: 958–965.
• 4.   Sato N, Kajimoto K, Keida T, Mizuno M, Minami Y, Yumino D, et al. Clinical features and outcome in hospitalized heart failure in Japan (from the ATTEND registry). Circ J 2013; 77: 944–951.
• 5.   Makita S, Yasu T, Akashi YJ, Adachi H, Izawa H, Ishihara S, et al. JCS/JACR 2021 guideline on rehabilitation in patients with cardiovascular disease. Circ J 2022; 87: 155–235.
• 6.   May GS, Eberlein KA, Furberg CD, Passamani ER, DeMets DL. Secondary prevention after myocardial infarction: A review of long-term trials. Prog Cardiovasc Dis 1982; 24: 331–352.
• 7.   O’Connor GT, Buring JE, Yusuf S, Goldhaber SZ, Olmstead EM, Paffenbarger RS, et al. An overview of randomized trials of rehabilitation with exercise after myocardial infarction. Circulation 1989; 80: 234–244.
• 8.   Taylor RS, Brown A, Ebrahim S, Jolliffe J, Noorani H, Rees K, et al. Exercise-based rehabilitation for patients with coronary heart disease: Systematic review and meta-analysis of randomized controlled trials. Am J Med 2004; 116: 682–692.
• 9.   Keteyian SJ, Patel M, Kraus WE, Brawner CA, McConnell TR, Piña IL, et al. Variables measured during cardiopulmonary exercise testing as predictors of mortality in chronic systolic heart failure. J Am Coll Cardiol 2016; 67: 780–789.
• 10.   Tashiro H, Tanaka A, Ishii H, Motomura N, Arai K, Adachi T, et al. Reduced exercise capacity and clinical outcomes following acute myocardial infarction. Heart Vessels 2020; 35: 1044–1050.
• 11.   Hiruma T, Nakayama A, Sakamoto J, Hori K, Nanasato M, Hosoda T, et al. Comprehensive cardiac rehabilitation following acute myocardial infarction improves clinical outcomes regardless of exercise capacity. Circ J 2024; 88: 982–992.
• 12.   Sjölin I, Bäck M, Nilsson L, Schiopu A, Leosdottir M. Association between attending exercise-based cardiac rehabilitation and cardiovascular risk factors at one-year post myocardial infarction. PLoS One 2020; 15: e0232772.
• 13.   Kanaoka K, Iwanaga Y, Fukuma N, Nakai M, Sumita Y, Nishioka Y, et al. Trends and factors associated with cardiac rehabilitation participation: Data from Japanese nationwide databases. Circ J 2022; 86: 1998–2007.
• 14.   Nakayama A, Takayama N, Kobayashi M, Hyodo K, Maeshima N, Takayuki F, et al. Remote cardiac rehabilitation is a good alternative of outpatient cardiac rehabilitation in the COVID-19 era. Environ Health Prev Med 2020; 25: 48.