Influence of previous percutaneous coronary intervention on clinical outcome of coronary artery bypass grafting: a meta-analysis of comparative studies

The prognostic significance of previous percutaneous coronary intervention (PCI) in patients undergoing coronary artery bypass grafting (CABG) is still unclear. Although many studies have reported adverse effects of previous PCI on postoperative mortality in CABG, as yet no meta-analysis has been carried out. We conducted this first meta-analysis to assess whether previous PCI increases postoperative mortality in CABG. MEDLINE and EMBASE were searched for relevant articles up to and including April 2014. Studies published in English satisfying the following criteria were included in the meta-analysis: (i) comparing CABG patients with previous PCI versus without previous PCI; and (ii) reporting hospital mortality. Our search identified 23 comparative studies, including 174 777 patients: 19 179 with previous PCI and 155 598 without previous PCI. Pooled analysis demonstrated that previous PCI had an adverse effect on hospital mortality: odds ratio (OR) 1.187, 95% confidence interval (CI) 1.075–1.312. Furthermore, subgroup analysis stratified by the proportion of multiple previous PCI (i.e. number of patients with multiple previous PCI/number of patients with single or multiple previous PCI) was performed. In the subgroup of studies with the proportion