Invited Commentary

Abstract

There is accumulating evidence that coronary artery bypass grafting (CABG) after previous percutaneous coronary intervention (PCI) is associated with higher early mortality and major adverse cardiac event (MACE) rates. Several possible explanations are addressed. Dysfunctional and denuded coronary endothelia after PCI initiate an inflammatory response with accumulation of platelets and neutrophils, resulting in microvascular thrombotic obstruction and distal microembolization. Coronary side branch obstruction resulting from stenting may lead to compromised collateral blood flow and focal infarctions. In addition, late structural changes may affect both the stented area and coronary artery territory distal to the stent, which would be the target area of a subsequent bypass graft anastomosis. The coronary artery distal to the stent may have inadequate runoff, and a bypass graft will have decreased patency. Preoperative use of antiplatelet medication such as clopidogrel may cause excess postoperative bleeding, and perioperative discontinuation of antiplatelet medication may cause in-stent thrombosis and adversely influence the results. The CABG patients with previous PCI may have an increased risk of repeated coronary revascularization during follow-up, because the rate of restenosis remains high even in the era of drug-eluting stents. As a result, impaired long-term outcome and decreased quality of life in the CABG patients with previous PCI also are anticipated. Mannacio and colleagues [1Mannacio V. Di Tommaso L. de Amicis V. et al.Previous percutaneous coronary interventions increase mortality and morbidity after coronary surgery.Ann Thorac Surg. 2012; 93: 1956-1963Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar] provide early and late clinical outcomes after CABG in patients with previous PCI, compared with outcomes in CABG patients without previous PCI. History of PCI is identified as a risk factor for hospital mortality and MACEs among patients undergoing CABG. The authors also demonstrate that previous PCI is a risk factor for decreased survival at 5-year follow-up. The authors enrolled a large patient cohort (n = 7,855) and performed propensity-score matching with excellent discriminating power (c-statistic of 0.94). However, further data analysis is needed to draw a conclusion that previous PCI affects midterm outcomes after later CABG. Reevaluation, including late occurrence of cardiac death, nonfatal myocardial infarction, and reintervention-free survival, will strengthen the authors' hypothesis. In addition, operative strategy data, such as use of the left internal thoracic artery and saphenous vein grafts and completeness of revascularization, are lacking. Moreover, their survival curve is questionable. The authors indicate that hospital mortalities, which must be included, are not included in their analysis. Both survival curves of the two groups, however, start below 1.0, indicating that hospital mortalities are included in their survival analysis. Survival differences at 5-year follow-up appear to be due to the high hospital mortality in the PCI group patients, rather than late occurrence of events during follow-up. Despite several limitations in this article, I agree with the authors' conclusion and suggestion that all previous PCIs should be treated as a risk factor for subsequent CABG. Although the authors′ findings are not new, I hope this study will strengthen the current evidence for the harmful effects of previous PCI on our CABG patients. Previous Percutaneous Coronary Interventions Increase Mortality and Morbidity After Coronary SurgeryThe Annals of Thoracic SurgeryVol. 93Issue 6PreviewThis multicenter study investigated the impact of previous percutaneous coronary interventions (PCI) on postoperative outcome and 5-year survival of subsequent coronary artery bypass grafting. Full-Text PDF