Effect of prior percutaneous coronary intervention on the results of coronary artery bypass grafting in the drug-eluting stent era

Objectives: An increasing number of CABG patients is treated today by percutaneous coronary interventions (PCI) prior to surgery. Until now there is only little and controversial evidence regarding the extent at which prior PCI adversely affect CABG results, and if, which are the most unfavorable PCI factors.

Methods: A total of 1,128 patients presenting history of at least one PCI undergoing an isolated coronary bypass operation between 2003 and 2008 were analyzed. Of these, 856 stable patients (75.8% of all) comparable to patients included in the Syntax trial was examined. The influence of individual variables on hospital and cumulative mortality was determined by logistic and Cox univariate and multivariate regression analyses. This included specific PCI variables and indications for surgery based on the prior PCI result.

Results: In the entire population, 42 patients (0.37%) presented PCI-associated complications. This event was accompanied with a significantly increased hospital mortality (OR 8.9; CI 3.79–21.12; p<0.001) and increased overall mortality (OR 3.8; CI 1.89–7.65; p<0.001). The number of implanted stents (HR 1.2; CI 1.00–1.56; p=0.049) also had an unfavorable effect on hospital mortality, while the implantation of more than one stent showed a negative effect only on cumulative mortality (OR 2.19; CI 1.04–4.60; p=0.037).

In the group of stable patients, the number of previous stent procedures showed a significantly negative effect on cumulative mortality (HR 1.74; CI 1.00–3.03; p=0.046). The hospital mortality of patients with a PCI-CABG interval of <3 days (OR 11.3; CI 5.31–24.1) and <30 days (OR 4.8; CI 2.43–9.71) was associated with a significantly increased mortality (p<0.001 each). In-stent restenosis (ISR) also showed a negative influence on hospital mortality (OR 9.94; CI 1.25–78.8; p=0.03). A bare metal stent restenosis was tended to be associated with a higher hospital mortality (OR 7.40; CI 0.92–59.52; p=0.06), while a DES-ISR did not show any negative effect. The follow-up period was 2.56 years. Cumulative survival at 1-, 3- and 5-years was 93.0%, 90.1% und 85.1% for the entire and 96.3%, 93.9% und 88.7 for the stable population.

Conclusion: This study identifies a number of PCI factors adversely affect prognosis after CABG. Beside non-elective indication as a consequence of suboptimal PCI result, an aggressive PCI with multi-stenting and several procedures adversely effect CABG results even in stable patients.