Perioperative Risk in Patients with Coronary Stents

Abstract & Commentary

By Andrew J. Boyle, MBBS, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco

Source: Tokushige A, et al. Incidence and outcome of surgical procedures after coronary bare-metal and drug-eluting stent implantation. A report from the CREDO-Kyoto PCI/CABG Registry Cohort-2. Circ Cardiovasc Interv 2012;5:237-246.

It is well known that the risk of perioperative major adverse cardiac events (MACE) is high in patients with coronary stents, especially early after stent implantation. The exact incidence varies from study to study but always seems to decrease with time. The effect of continuing antiplatelet therapy throughout the perioperative period on ischemic and bleeding endpoints is not known. Furthermore, the current generation of drug-eluting stents has lower stent thrombosis rates than earlier versions, so there is a need for more up-to-date data to guide us in managing patients with coronary stents who need to undergo surgery. Tokushige and colleagues present their data from a PCI registry involving 25 centers in Japan from 2005 to 2007. They describe a cohort of 12,207 patients with coronary stents, of whom 2398 (19.6%) subsequently underwent some type of surgery. Their primary ischemic endpoint was the combination of death, myocardial infarction (MI), and stent thrombosis (ST — definite or probable). The primary bleeding endpoint was moderate or severe bleeding by the GUSTO criteria. The types of surgery were varied and ranged from major to minor procedures. If we consider "high-risk surgery" to include intraperitoneal, intrathoracic, or suprainguinal vascular surgery, then 38.1% of the cohort underwent high-risk surgery.

Not unexpectedly, patients who underwent surgery were older and had more comorbidities than those who did not. The primary endpoint of death/MI/ST after 3 years occurred in 9.6% when surgery was performed early (within 6 weeks) after PCI, but this rate declined to approximately 2% thereafter and never declined further. Interestingly, there was no difference in the rate of perioperative death/MI/ST according to whether the patient had received bare metal stents (BMS) or drug-eluting stents (DES). Single antiplatelet therapy seemed to be adequate in this study, with no extra protection (and possible harm) conferred by continuing dual antiplatelet therapy (DAPT). The authors conclude that surgical procedures were commonly performed after coronary stent implantation, and the risk of ischemic and bleeding complications in surgical procedures was low. In patients selected to receive DES or BMS, there were no differences in outcomes. Perioperative administration of DAPT was not associated with lower risk for ischemic events.

Commentary

This registry is one of the larger registries of patients with coronary stents who subsequently undergo surgical procedures, and is also one of the most contemporary. The data are consistent with several other large registries that have been published recently, which have also shown high rates of MACE when surgery is performed early after stenting and that subsequently drop to lower levels. Some registries demonstrate higher absolute rates of perioperative MACE than this one. This may be due to several factors, including the inclusion of low-risk procedures performed under local anesthesia in this study, such as "dermatologic surgery," or endoscopic-guided GI procedures. Some series do not include such low-risk procedures. There is a need for a more uniform approach to data collection in these registries. Furthermore, there may also be differences between study populations, and data from Japan may not be generalizable to different racial groups or to more heterogeneous populations.

It is important to emphasize that of those patients who experienced the primary ischemic endpoint of death/MI/ST, 87% of them died. Other series also highlight this very high mortality from peri-operative events. Perioperative MACE events are not just low-level troponin elevations, they are significant and life-threatening cardiac events. This underscores the need to avoid elective PCI before surgery, and to postpone surgery if possible after PCI. I do not agree with the authors' conclusions that these are "acceptably low" levels. With an early MACE rate of 9.6%, and an 87% mortality within the MACE cohort, one could expect around 9% mortality from a surgical procedure performed within 6 weeks of PCI. It is hard to imagine that the surgeon performing a laparoscopic cholecystectomy would consider a 9% mortality acceptable.

The conundrum of whether to continue single or DAPT perioperatively has not been settled by this study. There are many variables to consider, including the bleeding risk from the type of surgery (e.g., neurosurgery vs dermatologic surgery) and the likelihood of surviving stent thrombosis (e.g., left main stent vs small side branch stent), that are not addressed in this study. What we can take from this paper, placed in the context of other registries, is that patients with stents should take single antiplatelet perioperatively if possible. But stopping all antiplatelet agents or continuing DAPT may also be reasonable alternatives if the clinical situation warrants it. Individual patients should be managed based on their overall ischemic and bleeding risk.

The most recent ACC/AHA guidelines suggest that all surgery be postponed for 12 months after DES, but can safely be performed after 6 weeks in patients who receive a BMS. However, the current study is consistent with other recent registries that suggest there is no difference in perioperative risk with BMS or DES. Thus, the difference between them no longer appears to be as great as once thought.