Cardiac rehabilitation-Clinical Review

What are the benefits of cardiac rehabilitation?

The benefits of cardiac rehabilitation for individuals after myocardial infarction and revascularisation and for those with heart failure have been reviewed comprehensively in several meta-analyses, including six Cochrane reviews and a recent clinical review from the US.18 19 20 21 22 23 24


A 2011 Cochrane review and meta-analysis of 47 randomised controlled trials that included 10 794 patients showed that cardiac rehabilitation reduced overall mortality (relative risk 0.87 (95% confidence interval 0.75 to 0.99), absolute risk reduction (ARR) 3.2%, number needed to treat (NNT) 32) and cardiovascular mortality (relative risk 0.74 (0.63 to 0.87), ARR 1.6%, NNT 63), although this benefit was limited to studies with a follow-up of greater than 12 months.25 With the exception of one large, UK based trial that showed little effect of cardiac rehabilitation on mortality at two years (relative risk 0.98 (0.74 to 1.30)),26 findings from meta-analyses and observational studies support a mortality benefit.27 Another systematic review and meta-analysis of 34 randomised controlled trials including 6111 patients after myocardial infarction showed that those who attended cardiac rehabilitation had a lower risk of all-cause mortality than non-attendees (odds ratio 0.74 (0.58 to 0.95)).28
The latest updated Cochrane review of exercise based cardiac rehabilitation for coronary heart disease reports an absolute risk reduction in cardiovascular mortality from 10.4% to 7.6% (NNT 37) for patients after myocardial infarction and revascularisation who received cardiac rehabilitation compared with those who did not.19 No significant reduction occurred in overall mortality,19 which contrasts with results in previous meta-analyses.25 29 The inclusion of patients from the UK based randomised controlled trial26 is cited as one reason for this lack of reduction in mortality.19 The negative findings of this trial have also led to scepticism about the content and delivery of UK based cardiac rehabilitation programmes in the late 1990s,30 31 and this controversial trial has been the subject of much debate.27 30 31 32

Reduced hospital admissions

Although the 2015 Cochrane review in coronary heart disease reported no reduction in the risks of fatal or non-fatal myocardial infarction or coronary revascularisation (coronary artery bypass graft or percutaneous coronary intervention), there was a reduced risk of hospital admission (from 30.7% to 26.1%, NNT 22).19 In another Cochrane review of 33 randomised controlled trials and 4740 patients with heart failure, exercise based cardiac rehabilitation reduced the risk of overall hospitalisation (relative risk 0.75 (0.62 to 0.92), ARR 7.1%, NNT 15) and hospitalisation for heart failure (relative risk 0.61 (0.46 to 0.80), ARR 5.8%, NNT 18).33

Improvement in psychological wellbeing and quality of life

A US observational study of 635 patients with coronary heart disease reported improvements in depression, anxiety, and hostility scores after cardiac rehabilitation.34 Early cardiac rehabilitation programmes only offered interventions that focused predominantly on exercise, but significant (P<0.01) improvements in anxiety and depression scores were reported in one randomised controlled trial of 210 men admitted with myocardial infarction undergoing gym based exercise training.35 Furthermore, a meta-analysis of 23 randomised controlled trials (3180 patients with coronary heart disease) that evaluated the impact of adding psychosocial interventions to standard exercise based cardiac rehabilitation reported a greater reduction in psychological distress (effect size 0.34) and improvements in systolic blood pressure and serum cholesterol (effect sizes −0.24 and −1.54 respectively).36
Several studies have reported improvement in psychological stress in patients with coronary heart disease who have attended cardiac rehabilitation: one recent US observational study of 189 patients with heart failure (left ventricular ejection fraction <45%) reported a decrease in symptoms of depression by 40% after exercise training cardiac rehabilitation (from 22% to 13%, P<0.0001).37 Also depressed patients who completed their cardiac rehabilitation had a 59% lower mortality (44% v 18%, P<0.05) compared with depressed dropout patients who did not undergo cardiac rehabilitation.37
A Cochrane review of exercise based rehabilitation for coronary heart disease showed that seven out of 10 randomised controlled trials that reported quality of life using validated outcome measures found “significant improvement,” but the authors were not able to pool the data to quantify the effect because of the heterogeneity of the outcome measures.25 Similarly, another Cochrane review of exercise based cardiac rehabilitation for heart failure reported a clinically important improvement in the Minnesota Living with Heart Failure questionnaire (mean difference 5.8 points (95% confidence interval 2.4 to 9.2), P=0.0007) in the 13 randomised controlled trials that used this validated quality of life measure.33

Cardiovascular risk profile

Before the use of statins for the secondary prevention of coronary heart disease, two observational studies demonstrated the beneficial effects of diet and exercise in improving lipid profiles.38 39 The findings of a small case series of 18 patients prescribed a low cholesterol diet and daily exercise for 30 minutes on a bicycle ergometer resulted in regression of coronary artery atheroma on angiography in seven of the 18 patients, compared with only one of 18 in the usual care group.39 Significant reductions in total serum cholesterol concentration (−2%, P=0.05) and low density lipoprotein:high density lipoprotein cholesterol ratios (−9%, P≤0.0001) were reported after 36 sessions of cardiac rehabilitation in another US observational study from the 1990s involving 313 cardiac patients.38
The prevalence of obesity in those attending cardiac rehabilitation in the US has increased in the past two decades, with >40% having a body mass index >30 and 80% with a body mass index >25.40 Ades et al conducted a randomised controlled trial of 74 overweight patients with coronary heart disease and showed that a “walk often and walk far” (“high calorie, high expenditure”) exercise protocol of 45-60 minutes per session of lower intensity exercise (70% peak oxygen uptake) resulted in twice the weight loss (8.2 kg v 3.7 kg, P<0.001) compared with the standard cardiac rehabilitation exercise session of 25-40 minutes. This study also reported significant improvements (P<0.05) in systolic blood pressure, body mass index, serum triglycerides, HDL cholesterol, total cholesterol, blood glucose, and peak oxygen uptake in the high calorie, high expenditure exercise group.

What are the risks of cardiac rehabilitation?

A French observational study of more than 25 000 patients undergoing cardiac rehabilitation reported one cardiac event for 50 000 hours of exercise training, equivalent to 1.3 cardiac arrests per million patient-hours.41 An earlier US study reported one case of ventricular fibrillation per 111 996 patient-hours of exercise and one myocardial infarction per 294 118 patient-hours.42
Patients with unstable angina, uncontrolled ventricular arrhythmia, and severe heart failure (New York Heart Association (NYHA) level 3 or 4, ejection fraction <35%) have been considered at high risk, with formal risk stratification (to include factors such as a history of arrhythmias and functional capacity) conducted by an experienced clinician before they engage in the exercise component of cardiac rehabilitation.1 However, the most recent Cochrane review found “no evidence to suggest that exercise training programmes cause harm in terms of an increase in the risk of all cause death in either the short or longer term” in patients with stable chronic heart failure (NYHA level 1–3).22

Access to cardiac rehabilitation

For those who have difficulty accessing centre based cardiac rehabilitation, or those who dislike groups, home based cardiac rehabilitation programmes are sometimes available.17 43 The most widely used programme in the UK is the Heart Manual44—a six week intervention that uses written material and a relaxation CD and is delivered by a trained healthcare facilitator who makes home visits and provides telephone support—which has been shown to be just as effective as centre based programmes.45 46

Overcoming barriers to cardiac rehabilitation

Despite robust evidence of clinical and cost effectiveness, uptake of cardiac rehabilitation varies worldwide and by patient group, with participation rates ranging from 20% to 50%.1 18 47 48 Poor uptake has been attributed to several factors, including physicians’ reluctance to refer some patients, particularly women and those from ethnic minorities or lower socioeconomic classes, and lack of resources, capacity, and funding.6 18 49 50 51 52 Adherence to cardiac rehabilitation programmes is affected by factors such as psychological wellbeing, geographical location, access to transport, and a dislike of group based rehabilitation sessions (box 3).13 18 43 The most effective way to increase uptake and optimise adherence and secondary prevention is for clinicians to endorse cardiac rehabilitation by inviting patients still in hospital after a recent diagnosis of coronary heart disease or heart failure to participate and for nurse led prevention clinics to be linked with primary care and cardiac rehabilitation services.2 5354 55 56
Novel ways of providing cardiac rehabilitation are emerging using the internet and mobile phones.57 58 A recent systematic review has evaluated alternative models of delivery59 that can be provided via secondary prevention clinics.60 Offering patients a choice of centre based, home, or online programmes on an equitable basis is likely to improve uptake across all groups of cardiac patients. Self management and collaboration with care givers can also improve uptake and outcomes.61 62 63
source BMJ 2015351 (Published 29 September 2015)

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