Heart Damage Common After Any Surgery; Test Could Detect It

Surgery comes with a risk of heart damage, and it may be higher than generally expected. In a study presented today at ACC Scientific Sessions P.J. Devereaux MD, PhD, director of cardiology at McMaster University in Hamilton, Canada put that heart injury risk at nearly 1 in 5 (18%) in patients having non-cardiac surgery.

Fortunately, he said, testing for a protein called high-sensitivity troponin T, one released into the blood with heart injury, can detect that the heart has been damaged so patients can be properly treated.

Devereaux said that without monitoring troponins, nearly all these heart injuries (93%) will be missed. Because of that lapse, he said, many of these patients die. “Our data show that unrecognized heart injuries may account for about 1 in 4 deaths that happen in the first 30 days after surgery,” he said.

The effects of surgery anywhere in the body create a “perfect milieu” for heart-tissue damage, he said. Those include bleeding blood clot formation, and long periods of inflammation. But these potential heart injuries are masked because patients typically receive painkillers that hide their symptoms.

The team enrolled 21,842 patients age 45 or older, including 41% who were 65 or older. Study sites were 23 hospitals in 13 countries. Procedures these patients had were elective, urgent, and emergency surgeries on all days of the week and all times of day.

Participating physicians measured high-sensitivity troponin T in the first 6 to 12 hours after surgery and again on each of the next 3 days.

These measurements were also taken before surgery. Patients were followed for up to 30 days and researchers recorded all major complications. The data were adjusted for p re-operative and surgical variables known to be associated with 30-day mortality such as active cancer.

Overall, 1.4 % of patients died during the first 30 days after surgery. Blood assays showed that patients with peak troponin T levels less than 5 ng/L had only a 0.1% risk of death within 30 days. But when peak troponin T levels were between 20 and 64 ng/L the risk of death was 3 times higher and the risk of 30-day mortality among this group was 3%.

When the level rose from 66 ng/L to 1000 ng/L the risk rose to 9.1% and over that it rose to 29.6%.

Getting baseline measures are key to ruling out a false indication of heart injury, he said.

Data from 3,904 patients who had a myocardial injury after non-cardiac surgery suggested that ischemic injury to the heart was the case in 24% of the deaths in the first 30 days after surgery.

Observational data suggested that the risk of death in post-surgical patients can be decreased by blood thinners and cholesterol lowering drugs, but “Data also suggests that only a minority of patients who get these injuries receive these drugs,” Devereaux said.

Post-operative management is “letting patients down,” he said.

One study limitation is that only 60% of patients in the study group had baseline measurements of the troponin taken.

The only financial support for the study received from outside parties was troponin-T assay provided by its manufacturer, Roche.

Next up, the researchers are conducting an international study to see if starting an anticoagulant based on elevated troponin T levels after non-cardiac surgery will reduce the numbers of deaths.