Heart surgery is becoming increasingly common as cardiovascular diseases affect more people worldwide.
Many of these procedures require surgeons to repair or replace damaged blood vessels using grafts—materials that reinforce or rebuild sections of the circulatory system.
While doctors often prefer using a patient’s own blood vessels for these repairs, this is not always possible, especially in people with conditions like diabetes that can weaken veins.
As a result, surgeons are using synthetic grafts more frequently. These artificial materials can save lives, but they carry a small risk of infection.
Although infections occur in fewer than 3% of cases, they can be extremely serious when they do happen.
Some studies estimate that up to 40% of patients with infected grafts may die within four years. Until now, doctors have not fully understood why these infections develop.
New research from Duke University suggests that the answer may lie in the structure of the materials themselves.
The study, published in the Journal of Biomedical Materials Research Part A, found that grafts made from uniform, simple materials may allow bacteria to spread more easily than materials with complex, tissue-like structures.
The research team examined different types of graft materials, including commonly used synthetic substances such as Teflon-like polymers, newer hydrogel materials, and bioengineered tissue that has had its living cells removed—a process known as decellularization.
These decellularized grafts retain the natural architecture of blood vessels while eliminating cells that could trigger immune reactions.
Scientists exposed samples of these materials to harmful bacteria to see how easily the microbes could move through them.
After several hours, bacteria were able to penetrate and travel across the hydrogel materials, which have a more uniform structure. However, when bacteria entered the decellularized tissue, they were unable to pass completely through it.
Researchers believe the complex internal structure of natural tissue acts as a barrier that slows or stops bacterial movement. In contrast, simpler materials may provide a more direct path for infection. The study also suggests that scar tissue forming around stitches—often similar in structure to synthetic materials—could be another entry point for bacteria.
Lead researcher A-Andrew Jones explained that grafts made from a patient’s own tissue rarely develop these infections, likely because natural blood vessels have this protective complexity. He believes future graft designs should mimic the internal architecture of real vascular tissue to reduce infection risk.
The researchers caution that their experiments were conducted in the laboratory rather than in living patients or animals, and the materials tested were not shaped like actual blood vessels. More research is needed to confirm whether the findings apply in real surgical settings.
Even so, the study offers an important clue for improving heart surgery outcomes.
By designing graft materials that more closely resemble natural tissue, scientists hope to reduce life-threatening infections and make these critical procedures safer for patients around the world.
Source: Duke University.
