Damage inflicted during non-cardiac surgery can reach heart cells and significantly raise a patient’s risk of mortality for up to one year after the procedure, according to research published this week in the American Heart Association (AHA) journal Circulation.

Heart cell damage during or after non-heart surgery—or perioperative myocardial injury (PMI)— is both dangerous and easily overlooked. In a study of more than 2,000 Swiss patients, first author Christian Puelacher, MD, PhD, and colleagues found PMI was “strongly” associated with death 30 days after surgery, both in patients with heart problems and those without cardiovascular issues.

“Patients with PMI are easily missed because they show no symptoms of heart disease in the majority of cases and only very rarely experience chest pain, which is the typical symptom of heart attack,” Puelacher said in an AHA news release.

To detect PMI, the researchers measured each patient’s blood levels of the heart protein troponin before and after surgery, which ranged from low-risk prostate procedures to high-risk peripheral artery bypasses in the study population. By tracking troponin levels, Puelacher and his team were able to record any damage inflicted to the heart that may have otherwise gone unnoticed.

One in seven patients aged 65 or older or those with preexisting coronary artery disease, peripheral artery disease or stroke developed PMI during the trial, the researchers reported. More than 90 percent of PMI patients reported run-of-the-mill chest pain, and those same patients were six times more likely to die of any cause within 30 days compared to their PMI-free counterparts.

“Recognizing PMI as a potential contributor to death after surgery might help improve the outcomes of non-cardiac surgery,” Puelacher said. “However, since there are no clear treatment recommendations for these patients, treatment currently has to be tailored to each patient individually. Therefore, further research is needed to find optimal PMI management strategies following detection.”