Simple Blood Test Improves Heart Attack and Stroke Risk Prediction

Troponin is a protein found in heart muscle cells that is released into the bloodstream when the heart is damaged. High-sensitivity troponin blood tests are commonly used in hospitals to diagnose heart attacks, but they can also detect ongoing, unnoticed damage to the heart, which can indicate an increased risk of future cardiovascular disease. These tests can be administered alongside routine cholesterol tests during visits to general practitioners. Now, a new study has revealed that individuals with higher levels of troponin in their blood are at a greater risk of experiencing a heart attack or stroke within the next 10 years. The researchers' modeling suggests that, among individuals currently classified as being at intermediate risk during routine cardiovascular health assessments, these tests could prevent one heart attack or stroke for approximately every 500 individuals tested.

In the study conducted by the London School of Hygiene & Tropical Medicine (LSHTM, London, UK), the researchers analyzed anonymized health data from over 62,000 participants in 15 studies across Europe and North America. Troponin levels were measured along with conventional risk factors, such as age, blood pressure, diabetes history, smoking status, and cholesterol levels. The participants were followed for about 10 years to track whether they had a heart attack or stroke. Current cardiovascular health assessments typically use an algorithm to predict the likelihood of a heart attack or stroke within the next 10 years based on these risk factors, including cholesterol levels from blood tests. By incorporating troponin test results with these conventional risk factors, the study found that the algorithm's predictions were up to four times more accurate than when relying on cholesterol levels alone.

Importantly, the researchers’ modeling indicated that the troponin test was particularly effective in identifying risks in the 35 percent of people currently assessed as being at intermediate risk for cardiovascular problems. Individuals with a 2.5 percent to 15 percent chance of having a heart attack or stroke within 10 years are categorized as having intermediate risk. This group presents a challenge for medical professionals since their risk is too high for reassurance, but not high enough to warrant immediate preventative treatment. The modeling revealed that including the troponin test results reclassified up to 8 percent of people originally categorized as intermediate risk to high risk. Offering preventative treatments, such as statins, to these individuals could prevent numerous serious cardiovascular events, including heart attacks and strokes.

“Troponin, even in the normal range, is a powerful indicator of silent heart muscle damage. As such, the test provides an extra layer of information that we can use to boost our accuracy when predicting people’s risk. We want to identify as many high risk people as possible, so that no-one misses out on the opportunity to get preventative treatment,” said LSHTM Professor Anoop Shah, lead author of the study published in the Journal of the American College of Cardiology. “Incorporation of troponin into current cardiovascular risk estimation guidelines can be useful for identifying high risk individuals who will benefit from preventative treatment, reducing the risk of future circulatory problems.”