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

Aim
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
14 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 was used to calculate mean differences or standardized mean differences (SMD).

Results
Of 15,873 reports identified, five 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 (2 RCTs; n=76) and on exercise capacity measured by peak VO2 (3 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 favor of CR, with a 4.16mL/kg/min increase in peak VO2 (SMD of 1.06, 95% CI -0.7 to 2.19, very low certainty).

Conclusions
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.