Stent type, timing may not drive outcomes in noncardiac surgeries

It may be time to dust off guideline recommendations on noncardiac surgery for patients who underwent recent coronary stenting, based on findings published online Oct. 7 in JAMA. Researchers cited emergency surgery and advanced cardiac disease, not stent type or antiplatelet issues, as the top determinants of adverse events.    

Guidelines revised in 2007 by the American College of Cardiology and American Heart Association call for a delay of one year for elective surgery after placement of a drug-eluting stent (DES) to allow for completion of dual antiplatelet therapy, and for surgery to be performed without cessation of antiplatelet therapy (APT) if surgery is urgent. The guidelines for bare metal stents (BMS) recommend a waiting period of six weeks and putting APT on a temporary hold.

“Delaying necessary noncardiac surgery can pose a significant clinical dilemma for a large number of patients,” wrote Mary T. Hawn, MD, MPH, of the University of Alabama at Birmingham, and colleagues. “The delays in surgery recommended by the guidelines are based on a limited and conflicting evidence base … It is not clear whether the lower observed MACE [major adverse cardiac events] rates in more recent studies are attributable to the effectiveness of guideline-driven delays of elective surgery together with continuing perioperative APT or reflect more reliable estimates of perioperative MACE rates in populations with stents, or both.”

Hawn and colleagues accessed the Veteran Affairs database to assess 41,898 operations performed on patients who between 2000 and 2010 underwent noncardiac surgery within two years of stent implantation. They targeted MACE (a composite of MI, revascularization and all-cause death) within 30 days of surgery as the primary outcome. They also estimated each patients’ cardiac risk at the time of operation using a six-point revised cardiac risk index based on administrative diagnosis codes.

They reported the rate of MACE totaled 4.7 percent within 30 days of surgery, with a higher rate for BMS than for DES (5.1 percent vs. 4.7 percent) in unadjusted analyses. Timing from stenting to surgery was associated with MACE, with rates decreasing with longer waiting intervals. But after adjustment, nonelective presentation, factors associated with advanced cardiac disease and higher revised cardiac risk index ranked at the top of the list as determinants for MACE.

Timing of surgery after six months of stent placement was not significantly associated with MACE, nor was stent type after six months of placement, and they found no association between APT cessation and MACE.      

“The present findings suggest that underlying surgical and cardiac risk, rather than stent type, are the primary factors associated with perioperative MACE; that event rates stabilize by six months; and that APT continuation does not substantially mitigate risk,” they summarized. “Accordingly, the current focus of the guidelines on differential timing recommendations by stent type may warrant reconsideration, and greater concentration may need to be placed on assessing and optimizing cardiac risk.”

They added that the study was retrospective and observational, and selection bias and other factors may have confounded results, making the findings hypothesis-generating only.

In an accompanying editorial, Emmanouil S. Brilakis, MD, PhD, and Subhash Banerjee, MD, of the Veterans Affairs North Texas Health Care System in Dallas, recommended that surgeries in recently stented patients should be done at primary PCI centers, where prompt treatment for perioperative stent thrombosis would be available. They also emphasized the need for close communication among physicians caring for the patient and restarting APT shortly after surgery.