Eighty-five percent of heart attacks and injuries after surgery go undetected because of a lack of symptoms, according to a new study based out of Hamilton Health Sciences.

But a simple blood test is all it takes to identify these possibly debilitating health issues, said Dr. P.J. Devereaux, head of cardiology and the Perioperative Cardiovascular Clinical Program at the Juravinski Hospital and Cancer Centre, and who led the study that was published in the March issue of the medical journal Anesthesiology.

The study found that only 15 percent of people who have heart attacks after surgery experience common symptoms like chest pain and pressure, shortness of breath and neck, jaw or arm pain.

“Most surgical patients who suffer a heart attack or injury will do so within the first 48 hours after surgery,” said Devereaux.  “During this time, most of these patients are typically taking pain medications, which can mask the symptoms of a serious heart injury.”

More than 8 million adults around the world have heart attacks or injuries after surgery every year, and 10 percent of those patients die within 30 days, according to Hamilton Health Sciences.

To perform the study, doctors monitored over 15,000 people over the age of 45 who were having non-cardiac surgery. They studied them for three days following their operation, and administered a simple blood test to measure troponin, a protein specific to the heart that is released into the blood when the heart muscle is injured. Patients with an elevated level of troponin were given an EKG to also assess heart damage.

Only 15 per cent of patients experienced traditional heart attack symptoms. Without that blood test, 85 percent of people who suffered heart attacks or injury would have gone undetected, Devereaux says.

The study also found that of all surgery complications, heart attack or injury is the most common reason patients that die within 30 days of surgery. Ten percent of patients who suffer a heart attack after surgery will die within 30 days, a Hamilton Health Sciences news release reads.