The research team adopted a test that is more responsive than the tests currently in use in US healthcare centers.
As part of the study, over 2,200 patients diagnosed with both type 2 diabetes and stable heart disease had their troponin concentrations measured. The researchers used high-sensitivity electrochemiluminescence to determine the levels of troponin. In a period of five years, 27 percent of the patients with elevated troponin levels died of a heart attack, stroke, or cardiovascular causes. In the people with normal troponin levels only 13% died of the above mentioned causes.
Of all the patients in the trial, half were given timely coronary revascularization – a surgical procedure wherein the coronary arteries are opened up with stents or coronary bypass grafts.
The results of the tests were very significant – almost four in every 10 patients with type 2 diabetes and stable heart disease had elevated levels of the protein troponin in their blood. What’s even more significant is the risk of death from heart attack, stroke or other cardiovascular causes within five years is twice as much in the patients with elevated levels of troponin.
The study also revealed that coronary artery bypass, the normal procedure for heart attack patients and patients with elevated troponin, did not decrease the abnormal troponin levels or the risk of serious heart conditions in stable patients.
The full details of the study can be found in the August 13, 2015 edition of The New England Journal of Medicine.
According to lead author Brendan Everett, M.D., M.P.H., at the Cardiovascular Medicine and Preventive Medicine division of BWH, “Though the patients in the study were not having heart attack symptoms, many of them had an abnormal troponin. This indicates that they were currently experiencing some sort of cardiac injury.” Because of this, the researchers were able to identify patients who had a high risk of heart attack, heart failure or death. And this, even after the patient’s other characteristics and risk factors were taken into consideration. The team is hopeful that armed with the knowledge of what causes elevated levels of troponin, doctors and clinicians can adopt new therapies to treat high-risk patients. For example, the study showed that coronary bypass did not reduce the risk of future heart attack or death.
Though the researchers knew that the increased troponin levels indicate ongoing injury to the cardiac muscle tissue, they were not completely clear on the cause of the injury. When they found blocked arteries and rectified them surgically, it did not reduce the risk of future heart attack or death in these patients. This prompted Everett to say, “We need alternative strategies to improve outcomes in this group of high-risk patients.”
The team hopes that more concentrated efforts will help them understand what causes abnormal troponin and why patients with abnormal troponin are at greater risk for cardiovascular-related death. Once these questions are answered, clinicians will be in a better position to suggest alternative treatment options and interventions for patients.
Source:
http://www.eurekalert.org/pub_releases/2015-08/bawh-prf081215.php