Most people think that when a major heart artery becomes completely blocked, the heart muscle beyond the blockage is doomed.
It seems logical. If blood can no longer reach part of the heart, that tissue should eventually die. But a new study suggests that the human heart may be far more resilient than many people realize.
Researchers from the University of East Anglia and collaborating institutions have found that the heart possesses a hidden backup system that can help keep heart muscle alive even when a major artery has been blocked for months.
More importantly, the researchers discovered a simple way for doctors to identify this hidden protection using a test that many patients already receive.
Their work was published in the journal Open Heart.
Heart disease remains one of the leading causes of death worldwide. One common problem is coronary artery disease, in which fatty deposits build up inside the arteries that supply blood to the heart. Over time, these deposits can narrow the arteries and sometimes block them completely.
A complete blockage that persists for months is known as a chronic total occlusion. Traditionally, doctors have faced an important question when they find such a blockage: Is the heart muscle beyond the blockage still alive, or has it already been permanently damaged?
The answer matters because treatment decisions often depend on it. If the heart muscle remains alive, restoring blood flow may improve symptoms and heart function. If the tissue is already scarred and dead, complex procedures may offer little benefit while exposing patients to unnecessary risks.
Scientists have long known that some people develop tiny alternative blood vessels called collateral vessels. These vessels grow around blockages and create new pathways for blood to reach the heart muscle. They function much like a natural bypass system created by the body itself.
The research team wanted to know whether the strength of these collateral vessels could predict whether heart tissue was still alive.
To find out, they studied 56 patients with chronic total occlusions. Each patient underwent a coronary angiogram, a common procedure that uses dye and X-rays to visualize blood flow in the heart’s arteries.
Using the angiogram images, doctors assigned a Rentrop score to each patient. This scoring system measures how effectively collateral blood vessels supply blood beyond a blockage. Higher scores indicate stronger natural bypass circulation.
The researchers then used cardiac magnetic resonance imaging, often called cardiac MRI, to determine whether heart muscle remained viable. Cardiac MRI is widely considered one of the best available methods for assessing heart tissue.
When the results were compared, a clear pattern emerged. Patients with stronger collateral circulation were far more likely to have living heart muscle despite having a completely blocked artery.
The Rentrop score proved to be the most important predictor of viability. Every increase in the score significantly increased the chances that the heart tissue remained alive. Patients with scores above one were especially likely to have viable heart muscle.
These findings could have major implications for patient care. Advanced imaging tests such as cardiac MRI are highly useful but may not always be immediately available. In some hospitals, patients may wait days or weeks for specialized imaging studies.
By contrast, angiograms are already part of routine care for many patients with coronary artery disease. If doctors can use information from these existing tests to estimate heart muscle viability, treatment decisions may become faster and more efficient.
The findings may also help reduce unnecessary procedures. Reopening a chronically blocked artery is often technically challenging and can take considerable time and resources.
Not every patient benefits from such treatment. Better identification of viable heart tissue could help doctors focus invasive procedures on the patients most likely to gain meaningful improvements.
The study also sends an encouraging message to patients. A completely blocked artery does not always mean irreversible damage. In some individuals, the heart adapts by building its own natural detours that continue supplying blood to vulnerable areas.
When analyzing the study, several strengths stand out. The researchers compared a simple angiogram score with cardiac MRI, which is considered the gold standard for evaluating heart muscle viability. This allowed them to directly test whether routine imaging could provide clinically useful information.
However, there are limitations. The study included only 56 patients, making it relatively small. Larger studies are needed to confirm the findings and determine how well the results apply to broader patient populations. Researchers will also need to investigate whether using the Rentrop score to guide treatment decisions improves long-term outcomes.
Even with these limitations, the research offers a practical and potentially valuable tool. By paying closer attention to the heart’s own natural bypass system, doctors may be able to make better treatment decisions and provide more personalized care for people living with severe coronary artery disease.
If you care about heart health, please read studies about how eating eggs can help reduce heart disease risk, and herbal supplements could harm your heart rhythm.
For more health information, please see recent studies about how drinking milk affects risks of heart disease and cancer, and results showing strawberries could help prevent Alzheimer’s disease.
Source: University of East Anglia.
