Hawn explains that after DES were introduced in 2004, they rapidly oversold bare metal stents until researchers noticed a proliferation of stent thrombosis in DES patients. That prompted the American Heart Association and the American College of Cardiology in 2007 to jointly issue guidelines calling for non-cardiac surgery to be delayed for patients for at least one year subsequent to DES implantation. The delay was intended to allow for one year of dual antiplatelet therapy (an aspirin and a platelet receptor inhibitor) to prevent adverse events such as clots.
Patients with bare metal stents are advised to wait six weeks under current guidelines, but Hawn's research suggests that surgeons might wait six months before operating on the BMS patient as well, especially if an acute myocardial infarction is what prompted the stent in the first place.
"It seems that if the patient had an acute myocardial infarction, their risk seems elevated for quite some time, close to the six-month mark. So if a patient had a BMS following an AMI we might want to pause and really question whether we should wait longer than six weeks for those patients."
Further research by her team will explore in more detail whether it's the stent itself that puts the patient at higher risk of a subsequent surgical adverse event, or the underlying cardiac disease.
Whatever the guideline is, patients who have had stents, especially DES, should undergo any surgery at a medical center with primary percutaneous coronary intervention capability in case a stent thrombosis occurs during the surgery, wrote Emmanouil Brilakis, MD, and Subhash Banerjee, MD, of the VA North Texas Health Care System and the University of Texas Southwestern Medical Center at Dallas In an accompanying editorial.
Patients with BMS can usually safely undergo surgery "within six weeks after coronary stent implantation with very low risk of stent thrombosis, they added. For patients with DES, surgery performed at least six 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."