Studies have shown that patients who have recently received a coronary stent and later undergo non-cardiac surgery are at higher risk for adverse cardiac events. “This is partly due to a combination of the patient’s heart disease and the body’s stress response to surgery,” explains Mary T. Hawn, MD, MPH. Research has identified several important cardiac drivers and surgical factors that can increase risks of adverse events, but little is known about the contribution of these factors to overall postoperative risk or if risks change over time following stent procedures.

Incremental Effects of Stents on Non-Cardiac Surgery

In a study published in the Journal of the American College of Cardiology, Dr. Hawn and colleagues compared adverse event rates in patients who previous received stents and underwent non-cardiac surgery with those not undergoing surgery. “Our purpose was to determine the incremental effect of surgery on perioperative events and estimate the relative contributions of surgical and cardiac factors,” Dr. Hawn says. The analysis matched 20,590 surgical patients to 41,180 non-surgical patients who previously received a stent between 2000 and 2010.

Stent recipients who underwent non-cardiac surgery had higher rates of heart attack and/or cardiac revascularization when assessed at 30 days after surgery. However, the incremental risk of non-cardiac surgery ranged from 3.5% immediately following stent implantation to 1.0% at 6 months. “After 6 months, the incremental risk of non-cardiac surgery remained stable out to 24 months except with high-risk operations,” says Dr. Hawn.

Assessing Stent Type: DES vs BMS

When incremental risk was examined by stent type, the overall adverse event rates were lower in patients with a drug-eluting stent (DES), regardless of whether they underwent surgery. The incremental risk of surgery was also similar for recipients of both bare-metal stents (BMS) and DES in the first 6 months. “Our observations provide further evidence that the higher rates of postoperative adverse cardiac events in patients with BMS are more likely due to the underlying patient conditions than from interactions with specific stent types and surgery,” Dr. Hawn says. “These data also reassure us that the incremental risk of surgery in patients with DES is minimal, especially when surgery is performed more than 6 months after stenting. Non-cardiac surgeries may benefit most from being delayed beyond 6 months in these patients.”

Important Implications for Clinicians

Clinicians should focus less on stent type and more on a patient’s cardiac and surgical risk factors when considering the optimal timing of surgery after coronary stent placement, according to Dr. Hawn. “As we gain a better understanding of these contributions to risk,” she says, “it may lead to the development of more tailored strategies to mitigate risks and improve preoperative assessments and decision-making.”