Research has shown many patients who undergo major noncardiac surgery are at risk for having a cardiovascular incident. However, a recently published study contains some startling new findings.

“Our study reveals a greater likelihood of having heart problems or dying after noncardiac surgery than has been recognized to date,” said study author Dr. Christian Puelacher of the University of Basel, Switzerland. “Patients are also at risk for a longer period than was previously thought.”

The study involved 2,265 patients who were either 65-85 years old, or 45-64 years old with cardiovascular disease, including coronary artery disease, peripheral artery disease or a past stroke. On average, patients were 73, and 43% were women. Researchers followed the patients for a year after surgery, monitoring them for heart attacks, heart failure, heart rhythm disorders and cardiovascular disease-related death. All patients had serial measurements of the protein troponin while hospitalized. When the heart muscle is injured, troponin is elevated in the blood.

“People who undergo major surgery are increasingly old and have other diseases, and these are the patients we focused on in our study," Puelacher said. “By providing information on postoperative complications, our research provides opportunities to make surgery even safer.”

Within 30 days, at least one heart complication was found in about 15% of patients. The 30-day rate of heart complications was highest in patients who had thoracic surgery, or procedures related to chest organs like the lung and esophagus, at 22%. Vascular surgery, which involves the arteries and veins, followed at 21%, and trauma surgery at 19%. At least one heart complication was found in 21% of patients within a year.

“This was one of the first studies to monitor patients for asymptomatic heart attacks after surgery,” Puelacher said. “These patients were at greater risk of subsequent events. One-third of patients who had an asymptomatic heart attack went on to have at least one more heart complication, compared to just 10% of those who did not have an asymptomatic heart attack. Our study suggests that measuring troponin levels before surgery and for two days afterwards could identify these patients and provide an opportunity to prevent further complications and death.”

Although most complications occur in the month after surgery, researchers found they can happen for much longer.

“Our results indicate that this high-risk patient group has an elevated likelihood of having an adverse cardiac event for three to five months after major surgery," Puelacher said.