Study Challenges Guidelines Regarding Delay for Noncardiac Surgery After PCI

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In patients who have undergone percutaneous coronary intervention (PCI) and require noncardiac surgery within 2 years, risk of major adverse cardiac events (MACE) is low with the exception of those requiring emergency surgery or having advanced cardiac disease, according to a registry study published online October 7, 2013, ahead of print in the Journal of the American Medical Association. The findings suggest current guidelines, which emphasize stent type and timing in decision making, should be reevaluated.

For the study, Mary T. Hawn, MD, MPH, of the University of Alabama at Birmingham (Birmingham, AL), and colleagues retrospectively examined 30-day MACE rates in 28,029 patients undergoing 41,989 noncardiac surgical procedures within 24 months of PCI (47.6% DES, 52.4% BMS).

Stent Type, Timing Not Significant

The rate of MACE (composite of all-cause mortality, MI, and cardiac revascularization) was 4.7% in the entire cohort. In unadjusted analyses, MACE rates differed by stent type (BMS 5.1% vs. DES 4.3%; P < 0.001). In addition, time between stenting and surgery appeared to affect MACE, with rates declining from 11.6% for surgeries performed in the first 6 weeks after stenting to 6.4% at 6 to 12 months and 3.5% at 12 to 24 months.

After adjustment, however, only emergency surgical admission, history of MI in the 6 months preceding surgery, and revised cardiac risk index greater than 2 were strongly associated with increased MACE (table 1).

Table 1. Predictors of 30-Day MACE After Noncardiac Surgery in PCI Patients

Stent type was ranked last in explanatory importance of the 12 variables in a nonlinear generalized additive model, and timing of surgery was ranked fifth. When stent type was analyzed separately, DES use did not predict MACE (adjusted OR 0.91; 95% CI 0.83-1.01). Additionally, a separate case-control analysis of 284 matched pairs found no association between antiplatelet cessation and MACE (OR 0.86; 95% CI 0.57-1.29).

According to the study authors, reports of stent thrombosis, both late after cessation of dual antiplatelet therapy and specifically in DES patients undergoing noncardiac surgery, led to a revision of AHA/ACC guidelines in 2007. The revised guidelines recommend continuing DES patients on dual antiplatelet therapy for at least 1 year with a delay of elective surgery until completion, or if the surgery is urgent, performing it without cessation of aspirin and clopidogrel. For BMS patients, on the other hand, the guidelines recommend delaying surgery for 6 weeks and temporary cessation of dual antiplatelet therapy.

Dr. Hawn and colleagues say their findings challenge the current focus on stent type and timing of surgery as the “primary decision points of perioperative risk assessment” and suggest that the additional cardiac risk factors identified in the analysis warrant more attention in algorithms for risk stratification in patients with stents.

Six-Month Wait After DES Appears Reasonable

In an accompanying editorial, Emmanouil S. Brilakis, MD, PhD, and Subhash Banerjee, MD, both of the VA North Texas Health Care System (Dallas, TX), say the study confirms that the risk of MACE declines with increasing time from surgery, stabilizing after 6 months.

“[S]urgery performed at least 6 months after DES implantation appears to carry low risk for stent thrombosis, especially with contemporary, second-generation DES, which have more biocompatible, durable polymer coatings,” they write. “Hence, nonurgent operations should be postponed until 6 months after stent implantation.”

In addition, Drs. Brilakis and Banerjee say close communication and collaboration should be maintained among surgeons, cardiologists, and anesthesiologists. If considered safe by the surgeon, antiplatelet therapy consisting of aspirin and clopidogrel (600-mg loading dose) should ideally be restarted during the first postoperative day, they note, in order to help reduce the risk of stent thrombosis. Clinicians should avoid more potent P2Y₁₂ inhibitors (ie, prasugrel and ticagrelor) to minimize bleeding risk early after surgery.

Apply Results with Caution

In an e-mail communication with TCTMD, Harold L. Dauerman, MD, of the University of Vermont (Burlington, VT), said the results address a common issue that occurs in about 20% of patients who undergo PCI. As “the largest registry study to date,” he added, it “provides us with the best quote of event rates as we consent patients for PCI and/or noncardiac surgery.”

However, he noted that there is an ‘uncertainty principle’ that applies to registry studies—the better the registry is at estimating event rates, “the worse we are at understanding the interaction of individual variables (stent type, pharmacology) with the adverse events,” he said. “That applies caution to this large registry. Any conclusion that DES are less risky than BMS is nearly impossible given the differences in patients receiving these stent types.”

According to Dr. Dauerman, an even greater concern is the suggestion that total cessation of antiplatelet therapy confers no increased risk to post-PCI patients undergoing noncardiac surgery. “It is very, very hard in a large registry to avoid . . . confounding and prove that continuing DAPT does not matter,” he stressed, adding that the case-control analysis of the current study excluded patients who underwent surgery within 6 weeks of PCI.

Dr. Dauerman cited 3 ways in which the results might be implemented.

The findings “should inform our consent process for patients undergoing PCI and noncardiac surgery, should allow us to move to a non-Class I guideline of avoiding surgery in the first 6 months after any PCI, and give encouragement to the anesthesia/interventional cardiology community that we are getting better at this,” he commented. “[But] continuing at least a baby aspirin in the perioperative period should remain standard of care for all PCI patients until this is definitively proven irrelevant based upon a randomized clinical trial.”

 

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Sources:
1. Hawn MT, Graham, Richman JS, et al. Risk of major adverse cardiac events following noncardiac surgery in patients with coronary stents. JAMA. 2013;Epub ahead of print.

2. Brilakis ES, Banerjee S. Patient with coronary stents needs surgery: What to do [editorial]? JAMA. 2013;Epub ahead of print.

 

 

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