Doctors in Boston discovered that high levels of a protein called ST2, which is secreted from heart muscle during a heart attack, predicts an increased risk of death or heart failure in the weeks after hospitalization.The discovery was made by investigators at Brigham and Women’s Hospital who were working on two different trials designed with the purpose of investigating medications for treating heart attacks. ST2 was identified in blood samples taken from study participants, and now doctors are trying to determine exactly what the relationship is between the protein and heart muscle stress.
The studies included a combined total of 810 patients. Blood levels of the ST2 protein were measured upon hospital diagnosis of a heart attack. Levels of ST2 were significantly higher in patients who died from the heart attack or who went on to develop new or worsening heart failure within 30 days.
Results from the studies were published on the Circulation web site at the end of April. Circulation is a journal of the American Heart Association.
After blood samples of the ST2 protein were measured, patients were separated into categories ranging from low to high levels. The risk of death or heart failure increased in a graded, stepwise fashion with higher levels of ST2.
Long-term prognosis based on ST2 levels remained reliable, even after measuring other predictors of heart health—such as heart rate, blood pressure, location of heart attack and age.
Doctors believe that ST2 is released when heart muscle cells become stressed or overloaded, and the healthy heart has to work harder to compensate. It also appears that inflammation in damaged heart tissue stimulates production of ST2.
In addition to looking promising as a novel predictor of cardiac health after heart attack, the researchers write that the data supports further investigation of ST2 as a potential novel target for modifying long-term outcomes in patients with heart attacks.
