When doctors discover that one of the heart’s major arteries is completely blocked, it often sounds like very bad news.
Coronary arteries supply oxygen-rich blood to the heart muscle, and a blockage can reduce blood flow and damage the heart.
For many years, doctors believed that heart muscle located beyond a long-term blockage was often permanently damaged or dead. But new research suggests the situation may not be so simple.
Scientists at the University of East Anglia, working with colleagues at Norfolk and Norwich University Hospital and Leiden University Medical Centre, have discovered that the heart may provide important clues about its own condition through a natural backup system.
Their findings could help doctors decide which patients are most likely to benefit from complex procedures and which patients may not need them.
The study was published in the journal Open Heart.
The heart has an amazing ability to adapt when blood flow is reduced. In some people, when a coronary artery becomes blocked, tiny blood vessels begin to grow around the blockage. These small vessels are called collateral vessels. They act like detour roads around a traffic jam, allowing blood to reach areas that would otherwise be deprived of oxygen.
These natural bypass vessels are usually much smaller than the main coronary arteries, but they can still provide enough blood flow to keep heart tissue alive. Doctors have known about collateral vessels for many years, but it has been difficult to determine how useful they are in predicting whether heart muscle is still healthy.
To investigate this question, researchers studied 56 patients who had a condition called chronic total occlusion.
This means one of their coronary arteries had been completely blocked for several months or longer. Chronic total occlusion is relatively common and occurs in about one out of every five patients with established coronary artery disease who undergo testing.
The research team compared two methods of assessing the heart. First, they used a routine angiogram, a procedure that allows doctors to see blood flow in the arteries. During the angiogram, they assigned each patient a Rentrop score. This score measures how well collateral blood vessels are supplying blood around a blockage.
The researchers then compared the Rentrop scores with results from advanced cardiac MRI scans. Cardiac MRI is considered one of the most accurate ways to determine whether heart muscle is still alive or has become permanently scarred.
The findings were striking. Patients with stronger collateral vessels were much more likely to have living heart muscle beyond the blockage. A Rentrop score above one strongly suggested that the affected heart tissue remained viable despite the blocked artery.
In fact, every increase in the Rentrop score more than doubled the likelihood that the heart muscle was still alive. The Rentrop score turned out to be the strongest independent predictor of heart muscle viability in the study.
This discovery could have important practical benefits. Procedures to reopen completely blocked coronary arteries are often lengthy, technically difficult, and expensive. They also carry risks. Not every patient gains meaningful benefits from undergoing these procedures.
If doctors can identify patients whose heart muscle remains healthy using information already available during a routine angiogram, they may be able to make treatment decisions more quickly and accurately. Patients who are likely to benefit can be prioritized for further testing or treatment, while others may avoid unnecessary procedures.
The findings may be especially valuable in hospitals where advanced cardiac MRI scanners are not readily available. In many healthcare settings, access to specialized imaging can involve delays, costs, and long waiting lists. A simple angiogram-based assessment could help guide decisions while waiting for additional tests.
The study also changes how doctors think about blocked arteries. A complete blockage no longer automatically means that the heart muscle beyond it is permanently lost. In some patients, the body’s own natural response may preserve heart tissue through these tiny collateral vessels.
When reviewing the findings, it is important to note that the study involved a relatively small group of 56 patients. Larger studies will be needed to confirm the results and determine how they apply across different patient populations. However, the findings are promising because they rely on information doctors already collect during routine care.
The research highlights the remarkable ability of the human body to adapt to disease. The heart’s natural bypass system may provide a simple and practical way to identify living heart muscle, helping doctors choose the right treatment for the right patient.
If future studies confirm these results, patients with blocked arteries could receive faster decisions, fewer unnecessary procedures, and more personalized care.
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Source: University of East Anglia.
