Effects of cardiac rehabilitation on the severity of angina, health-related quality of life, and exercise capacity among adults living with microvascular angina: a systematic review and meta-analysis

AIMS: To evaluate the effect of exercise-based cardiac rehabilitation (CR) on the severity of angina, health-related quality of life (HRQoL), and exercise capacity in adults living with microvascular angina (MVA). METHODS AND RESULTS: Fourteen online databases were searched to identify randomized controlled trials (RCTs) comparing adults with MVA receiving CR to those receiving a control intervention involving no exercise. Meta-analyses using random-effects models were used to calculate mean differences or standardized mean differences (SMD). Of 15 873 reports identified, 5 studies (222 participants) were included. Risk of bias for all outcomes were judged as 'some concerns' or 'high'. Mean ages ranged from 51 to 64 years, and 97.3% were women. Meta-analysis of CR's effect on the severity of angina was not feasible due to limited data. Meta-analysis on HRQoL was conducted at the domain level of Short Form-36 questionnaire (two RCTs; n = 76) and on exercise capacity measured by peak VO2 (three RCTs; n = 101). The HRQoL outcome was classified as 'very low certainty', indicating very little confidence in the effect estimates. The meta-analysis on exercise capacity showed a clinically meaningful change in peak VO2 in favour of CR, with a 4.16 mL/kg/min increase in peak VO2 (SMD of 1.06, 95% CI -0.7 to 2.19, very low certainty). CONCLUSION: CR may improve exercise capacity in patients living with MVA compared to controls; however, the evidence is very uncertain. High-quality RCTs are needed to rigorously determine the impact of CR on the severity of angina, HRQoL, and exercise capacity in patients living with MVA.