An increasing number of patients with coronary stents have a noncardiac operation each year. Approximately 5 to 15 percent of patients will present for a surgical procedure within the first year after stent placement.
“The surgical environment is unique, with a complex interplay of multiple factors that predispose patients with coronary stents to a high risk of major adverse cardiovascular events,” said Priya A. Kumar, M.D., FASA, Professor of Anesthesiology, University of North Carolina, Chapel Hill. Dr. Kumar led the Monday session “Perioperative Management of Patients with Coronary Stents.”
Dr. Kumar described the evolution of coronary stents, beginning with the first bare metal stents (BMS) approved in 1993. A high incidence of in-stent restenosis with BMS led to the development of drug-eluting stents (DES), which had their own shortcoming of stent thrombosis; newer drugs in these stents have made them safer and more effective. The newest type of stent is bioresorbable, but an FDA safety alert in 2017 limited its use. Dr. Kumar said anesthesiologists may see patients with these stents.
Knowing the type of stent in a patient is a factor in decision-making, as different stents are associated with different risks for major adverse cardiovascular events (MACE), as well as with different safe timeframes for a surgical procedure and the type of antiplatelet therapy, said Dr. Kumar.
Recommendations for the timing of a surgical procedure have been driven by the results of studies to evaluate perioperative morbidity among patients with stents. This includes recommendations from the American College of Cardiology (ACC)/American Heart Association (AHA). The recommended timing has changed over several iterations of the ACC/AHA guidelines; according to the 2016 guideline, a surgical procedure should be delayed for at least one month after implantation of a BMS and three to six months after implantation of a DES (and longer for high-risk patients).
Another important factor in decision-making is the continuation of antiplatelet therapy in the perioperative period. The dilemma is balancing the risk of postoperative or intraoperative bleeding against the risk of thrombosis. Guidelines recommend that aspirin be continued indefinitely, including during the perioperative period, regardless of the type of stent or its indication. The duration of dual antiplatelet therapy (DAPT) varies according to the type of stent and the indication.
According to the 2016 ACC/AHA guidelines, patients who received a stent for stable ischemic heart disease should continue DAPT for at least one month after implantation of a BMS and for at least six months after implantation of a DES. Patients who received a stent for acute coronary syndrome should continue DAPT for at least one year after stent placement, regardless of the type of stent.
If DAPT must be withheld in the perioperative period, bridging therapy with a shorter-acting antiplatelet agent can be used. Cangrelor is preferred because of its short half-life, but tirofiban and eptifibatide are other options. Heparins should not be used because their antiplatelet effects are minimal.
“Typically, a multidisciplinary team should coordinate these efforts, as cardiologists are experienced in the use of intravenous antiplatelet agents,” said Dr. Kumar.
Dr. Kumar cautioned against heavy reliance on guidelines because of their limitations. No randomized controlled trials have been conducted on stents in the perioperative setting, so guidelines are not based on strong evidence. Recommendations do not make distinctions according to comorbidities, surgical invasiveness or angiographic risk factors. She recommended reviewing a patient’s angiographic findings to help better identify risks. She added that it is important to note if a patient takes a drug other than clopidogrel.
“This is a red flag. Another drug was used either because the patient is at high risk or was resistant to clopidogrel. Look at the angiographic details to learn more,” she said.