Difference in spontaneous myocardial infarction and mortality in percutaneous versus surgical revascularization trials: A systematic review and meta-analysis

Objectives: It has been hypothesized that the survival benefit of coronary artery bypass (CABG) compared with percutaneous interventions (PCI) may be associated with the reduction in spontaneous myocardial infarction (SMI) achieved by surgery. This, however, has not been formally investigated. The present meta-analysis aims to evaluate the association between the difference in SMI and in survival in PCI versus CABG randomized controlled trials (RCTs).

Methods: A systematic search was performed to identify all RCTs comparing PCI with CABG for the treatment of coronary artery disease and reporting SMI outcomes. Generic inverse variance method was used to pool outcomes as natural logarithms of the incident rate ratios across studies. Subgroup analysis and interaction test were used to compare the difference of the primary outcome among trials that did and did not report a significant reduction in SMI- in the patients treated by CABG. Primary outcome was all-cause mortality; secondary outcome was SMI.

Results: Twenty RCTs were included in the meta-analysis. A statistically significant difference in SMI in favor of CABG was found in 7 of the included trials (35%). Overall, PCI was associated with significantly greater all-cause mortality (incident rate ratio, 1.13; 95% confidence interval, 1.01-1.28). At subgroup analysis, a significant difference in survival in favor of CABG was seen only in trials that reported a significant reduction in SMI in the surgical arm (P for interaction 0.02).

Conclusions: In the published PCI versus CABG trials, the reduction in all-cause mortality in the surgical arm is associated with the protective effect of CABG against SMI.