By Lisa Rapaport

(Reuters Health) – Patients who have so-called percutaneous coronary intervention (PCI) procedures to restore blood flow to the heart may be more likely to have complications with non-cardiac surgery than other people, a U.S. study suggests.

PCI is commonly performed for ischemic heart disease, or heart problems caused by narrowed arteries, and for so-called acute coronary syndrome, which is typically caused by clots or plaque in the arteries. During PCI procedures, doctors thread a thin catheter through the artery to place a tiny mesh cage known as a stent at the site of blockage to prop open the vessel and restore blood flow to the heart.

Patients who have a coronary stent placed are known to have an increased risk of cardiac complications during and after non-cardiac surgeries, especially when operations are done soon after PCI, said Dr. Nathaniel Smilowitz of NYU School of Medicine, the lead author of the study. That’s why clinical guidelines recommend that, when possible, surgeries be postponed for at least one year after PCI.

But some previous research suggests that up to 7.5% of patients require surgery within the first six months of PCI and up to 20% undergo surgery within two years, Smilowitz and colleagues note in the American Heart Journal.

The current study examined data on 221,379 patients who had PCI. Overall, 3.5% of these patients returned to the hospital for non-cardiac surgery within six months, and 41% of these cases were elective (non-emergency) surgeries.

“This study suggests that despite the guidelines to avoid surgery in the first year after a stent, as many as about 30,000 patients each year in the United States may wait fewer than six months before surgery,” Smilowitz said by email.

“Non-cardiac surgeries early after placement of a coronary stent were associated with poor outcomes, and with an 8% risk of heart attack or death during the hospital stay,” Smilowitz said. “Patients and providers should know these risks and avoid this scenario whenever possible.”

Out of all the patients who returned for non-cardiac surgery within six months of discharge after PCI, 339 of them, or 4.4%, died from various causes, the study found.

The risk of death or a nonfatal heart attack was greatest for non-cardiac surgeries performed within one month of discharge after PCI.

“Patients who require coronary stents tend to be older adults with other cardiac risk factors and many have other chronic illnesses,” Smilowitz said. “These patients may also require non-cardiac surgery to treat other ailments; in this study vascular surgery, orthopedic surgery, and general abdominal surgery were the most commonly performed surgeries in the first six months after placement of a coronary stent.”

One reason surgery can be risky after PCI is because patients are prescribed blood thinners, including aspirin, to prevent blood clots from developing after the placement of a stent in the arteries, Smilowitz said.

“When these agents are discontinued prior to the operating room, the inflammation associated with surgery can provoke blood clots within the stent, which can cause a heart attack,” Smilowitz said.

“When blood thinners are continued during non-cardiac surgery, there is a significant risk of bleeding, which can be life threatening,” Smilowitz added. “This balance of clotting and bleeding risk during and immediately after surgery makes this a particularly vulnerable time period for patients with coronary stents.”

SOURCE: American Heart Journal, online July 22, 2019.