Time has come to develop routine exercise training interventions in patients with chronic coronary syndrome

This editorial refers to ‘Exercise-based cardiac rehabilitation versus percutaneous coronary intervention for chronic coronary syndrome: impact on morbidity and mortality’, by B.J.R. Buckley et al., pp. 1074–1080. Recently, after the COURAGE trial,1 also the ISCHEMIA2 trial showed that in patients with chronic coronary syndrome (CCS), including those with multivessel coronary artery disease, a conservative strategy is superior to an invasive one in reducing the primary endpoint including death from cardiovascular causes, myocardial infarction, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest. Invasive strategy remains a useful option for symptoms control. Both studies confirm that an aggressive cardiovascular risk factor control, reducing plaques vulnerability, may improve the prognosis of patients with CCS. In the COURAGE and ISCHEMIA trials, regular exercise was recommended, but a routine supervised exercise programme was not provided. Nevertheless, most patients enrolled in exercise-based cardiac rehabilitation programmes had recent acute myocardial infarction or coronary artery bypass graft surgery, and only very few patients were enrolled for CCS. In 2004, in a randomized study from the University of Leipzig,3 compared with percutaneous coronary intervention, a 12-month programme of regular physical exercise in 101 selected patients with CCS was superior for event-free survival and exercise capacity at lower costs, notably due to reduced re-hospitalizations and repeated revascularizations. In the present study, Buckley et al.,4 from the University of Liverpool, retrospectively studied 18383 patients with CCS, of which 12676 had undergone percutaneous coronary intervention and 4368 exercise-based cardiac rehabilitation. A conservative strategy with intensive cardiovascular risk factors management significantly reduced all-cause mortality, re-hospitalizations, acute myocardial infarction, and stroke. The study presents several main limitations, because no data are available on coronary anatomy, type of exercise, adherence to treatments, left ventricular function, and extent of myocardial ischaemia, potentially causing a possible bias, which could affect the selection of patients and the results. Overall, cardiac rehabilitation is a complex intervention that includes exercise training, physical activity promotion, health education, cardiovascular risk management, and psychological support, personalized to the individual needs of patients with heart disease. The recent 2021 Cochrane review,5 based on 84 trials that included patients with coronary artery disease, mainly after acute myocardial infarction or coronary revascularization, showed that exercise-based cardiac rehabilitation has no effect on all-cause mortality, and shows a significant reduction of fatal and non-fatal myocardial infarctions, and all-cause re-hospitalizations. The Cochrane review has been strongly criticized for the inclusion of older randomized controlled trials (RCTs), spanning the period from 1974 to 2020, conversely, in the CROS-II analysis,6 including only RCTs available after 1995, exercise-based cardiac rehabilitation reduced all-cause mortality. Unfortunately, the strong evidences of exercise-based cardiac rehabilitation are confined to low-risk patients who are survived to an acute myocardial infarction and no randomized clinical trials tested exercise among patients with CCS. Recently, Eijsvogels et al.7 collected data from 83 000 Dutch patients undergoing exercise-based cardiac rehabilitation showing a significant reduction of all-cause mortality also in patients with CCS, but, again, a selection bias may affect the results. According to recent studies, a moderate exercise training intervention may induce anti-atherogenic adaptations, irrespective of traditional cardiovascular disease risk factors, stimulate parasympathetic regulation conferring protection against arrhythmias; moreover, muscle-derived myokines promote a healthy anti-inflammatory milieu, exercise improves myocardial regeneration capacity, in part through stimulation of the circulating angiogenic cells, reverses the loss of muscle strength and mass.8 Finally, exercise can promote a healthy gut microbiota while protecting the permeability and function of the gut barrier. Even if the safety and effectiveness of the traditional medically supervised, centre-based cardiac rehabilitation model are well established in reducing hospital readmissions, events, and mortality in patients with stable cardiovascular disease, including those with CCS, a home-based cardiac rehabilitation programme could be preferred in this setting.9 However, so far the impact of home rehabilitation has been substantially limited by a significant underuse among eligible patients. In conclusion, beyond the limitations of the study, Buckley et al.4 show once again that an exercise training intervention may improve the prognosis in patients with chronic heart disease, including those with CCS, and that this programme should be routinely included in the treatment schedule. So far, exercise training intervention programmes are carried out in hospital settings, but time has come to develop out-of-hospital more facilities to promote exercise training and, after a short supervised period, telerehabilitation with remote monitoring. Conflict of interest: none declared. The opinions expressed in this article are not necessarily those of the Editors of the European Journal of Preventive Cardiology or of the European Society of Cardiology.