Six RCTs (n=2,607) were included. The largest of these (OAT/TOSCA study, n=2,166) provided data for clinical outcomes and incorporated a substudy (n=381) which provided data for EF. The other 5 RCTs were much smaller (total n=441).
In the largest study, methods for randomisation and allocation concealment were described. Only one other study reported on randomisation procedures and no others adequately described allocation concealment. The outcome assessment was adjudicated centrally in the largest study and one other study. Assessors were described as blinded to the outcome of EF in all but one study, and all studies provided some information on withdrawals and clearly reported rates of follow-up.
Clinical outcomes of death, MI, death and MI combined, and CHF (6 RCTs, n=2,607): there was no statistically significant difference between the groups for any of these outcomes. No statistically significant heterogeneity was found.
LVEF (6 RCTs, n=653): there was a small statistically significant difference between the groups for this outcome, favouring the PCI group (absolute mean difference 1.4%, 95% confidence interval: 0.1, 2.8, fixed-effect model). There was no statistically significant heterogeneity (χ2 test, p=0.13), but some heterogeneity could not be excluded as the I2 statistic was 41%. When a random-effects model was used, this result was no longer statistically significant.
Early studies versus OAT/TOSCA study: for clinical outcomes, the OAT/TOSCA study found no benefit and a trend for harm associated with PCI. These findings differed significantly from the findings of earlier studies (z statistic, p=0.02), which had found a statistically significant benefit associated with PCI. Similarly, for the outcome of change in EF, the TOSCA study found no benefit associated with PCI, whereas the earlier studies had found a 2% benefit.