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Noncardiac Surgery in Patients with Coronary Stents
Abstract & Commentary
By Andrew J. Boyle, MBBS, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco. Dr. Boyle reports no financial relationships relevant to this field of study. This article originally appeared in the December 2009 issue of Clinical Cardiology Alert. It was edited by Michael H. Crawford, MD, and peer reviewed by Ethan Weiss, MD. Dr. Crawford is Professor of Medicine, Chief of Cardiology, University of California, San Francisco, and Dr. Weiss is Assistant Professor of Medicine, Division of Cardiology and CVRI, University of California, San Francisco. Dr. Crawford is on the speaker's bureau for Pfizer, and Dr. Weiss reports no financial relationships relevant to this field of study.
Source: van Kuijk P, et al. Timing of noncardiac surgery after coronary artery stenting with bare metal or drug-eluting stents. Am J Cardiol. 2009;104:1229-1234.
Percutaneous coronary intervention (PCI) with bare-metal stents (BMS) or drug-eluting stents (DES) remains the most common method of coronary revascularization. Dual anti-platelet therapy with aspirin and a thienopyridine dramatically reduces the incidence of coronary stent thrombosis. However, around the time of noncardiac surgery, the risk of stent thrombosis rises. In addition, the bleeding risk also rises in patients who continue dual anti-platelet therapy. Thus, there is considerable uncertainty about the most appropriate time to perform noncardiac surgery in patients who have coronary artery stents, and whether or not to continue dual anti-platelet therapy throughout the perioperative period. Accordingly, van Kuijk et al performed a retrospective analysis of 550 patients who underwent noncardiac surgery at various intervals after PCI and described the incidence of major adverse cardiac events (MACE) in the 30 days following the noncardiac surgery.
From 2000 to 2007, 550 patients at their center underwent PCI and, subsequently, had noncardiac surgery. All patients from 2000-2002 had BMS (n = 174) and all patients from 2002-2007 had DES (n = 376). Patients with BMS were routinely prescribed aspirin for life and clopidogrel 75 mg daily for at least 30 days. Patients receiving DES were routinely prescribed aspirin for life and clopidogrel 75 mg daily for at least three months (sirolimus) or six months (paclitaxel). Patients with DES had higher cardiac risk profile. They had increased rates of current or former smoking (70% vs. 43%; p < 0.001), diabetes (25% vs. 15%; p = 0.01), dyslipidemia (57% vs. 47%; p = 0.02), were older (63.3 years vs. 61.2 years; p = 0.04), had higher incidence of renal failure (11% vs. 4%; p = 0.01), and were less likely to be on a calcium channel blocker (26% vs. 48%; p < 0.001). In addition, patients receiving DES had longer duration of clopidogrel therapy (six months [1-6 months] vs. two months [1-3 months]; p < 0.001) and were more likely to receive statins (61% vs. 52%; p = 0.05), likely reflecting the evolution of medical therapy between the years of the procedures. Other baseline clinical demographics were similar between groups.
Patients underwent surgery that was high risk in 22% and 15%, intermediate risk in 49% and 51%, and low risk in 31% and 33% in those receiving DES and BMS, respectively. Perioperative complications were defined as the occurrence of MACE (death, myocardial infarction, stent, thrombosis, or repeat revascularization) within 30 days of the surgery. Intervals between PCI and surgery were arbitrarily divided into < 30 days, < 3 months, and > 3 months for patients receiving BMS, and into < 30 days, 30 days to 3 months, 3 to 6 months, 6 to 12 months and > 12 months for patients receiving DES.
Results: Perioperative MACE occurred more frequently when noncardiac surgery was performed within 30 days of PCI; the incidence declined thereafter. In patients who had received BMS, perioperative MACE occurred in 50% of those undergoing noncardiac surgery within 30 days of PCI, despite all patients receiving dual anti-platelet therapy up until the time of surgery. MACE occurred in 14% undergoing surgery 30 days to 3 months after PCI and in 4% at more than three months after PCI (p < 0.001).
In patients who had received DES, perioperative MACE occurred in 35% of those undergoing noncardiac surgery within 30 days of PCI, 13% at 30 days to three months, 15% at 3 to 6 months, 6% at 6 to 12 months, and 9% after 12 months from PCI (p < 0.001). After multivariable analysis, noncardiac surgery within 12 months of PCI with DES was associated with an increased risk of perioperative MACE (hazard ratio 2.0, 95% CI 1.1 to 3.5).
In patients who experienced MACE, 45% and 55% had been receiving single and dual anti-platelet therapy, respectively (p = 0.92), suggesting that continuing dual anti-platelet therapy perioperatively does not prevent MACE. However, dual anti-platelet therapy was associated with higher rates of severe bleeding than single anti-platelet therapy (21% vs. 4%; p < 0.001). Importantly, of all the MACE events that occurred following noncardiac surgery, regardless of the interval since PCI, over 80% were fatal. van Kuijk et al conclude that there is an inverse relation between the interval from PCI to noncardiac surgery and perioperative MACE, and that continuation of dual anti-platelet therapy until surgery did not provide complete protection from MACE.
There are no prospective, randomized trials to guide the timing of noncardiac surgery in patients who have coronary artery stents. In this retrospective study, van Kuijk et al confirm previous series that the rates of perioperative MACE are high in patients having surgery early after PCI and become lower with time. Importantly, they showed that the risk of perioperative MACE never reaches zero, and that continuation of dual anti-platelet therapy does not abolish this risk. Furthermore, their data highlight the importance of perioperative MACE in this group the high incidence of death (83% in DES and 91% in BMS) in patients experiencing MACE.
In deciding the optimal time for noncardiac surgery after PCI, clinicians must make an informed decision about the importance of the surgery vs. the risk of perioperative MACE (which carries a high mortality). Certainly within the first 30 days, the risk of MACE and death are very high, and surgery should be performed only for life-threatening emergencies. Current guidelines suggest that elective surgery should be postponed at least six weeks after BMS and 12 months after DES. These data confirm the importance of waiting. Furthermore, van Kuijk et al have demonstrated that dual anti-platelet therapy does not eliminate the risk of perioperative MACE, but does increase the risk of bleeding.