Dose-finding, experimental medicine evaluation of sodium valproate for the prevention of post-cardiac surgery myocardial injury

Every year, thousands of people undergo operations to repair their hearts, a procedure that requires stopping the heart temporarily to allow surgeons to work. While this is often life-saving, the act of stopping and restarting the heart creates a specific kind of stress that can damage the heart muscle itself. This damage, known as myocardial injury, happens in more than a quarter of these surgeries and is a leading cause of early death or a slow, difficult recovery. For decades, doctors and scientists have searched for a way to shield the heart from this inevitable stress, but no drug has yet proven effective enough to become standard care. The heart is a resilient organ, yet it is vulnerable to the metabolic shock of surgery, and finding a way to make it tougher without causing new problems has remained one of the most stubborn challenges in modern medicine.

In a recent study, researchers tested an old, well-known medication called sodium valproate to see if it could protect the heart during this critical window. Sodium valproate is commonly used to treat neurological conditions like epilepsy, but scientists had noticed in laboratory models that it might also help heart cells survive severe stress. The idea was that by giving the drug before surgery, the heart might be primed to handle the shock better. However, the drug is known to have unpredictable effects on the body; it can cause side effects ranging from mild stomach issues to serious liver problems, and the amount of drug that actually works in the body does not always match the amount taken. Because of this, the researchers did not just test if the drug worked; they first had to figure out the right dose and the right amount of time to take it to ensure it was safe and that patients could actually stick to the plan.

The study involved adults waiting for heart surgery at a single hospital in the United Kingdom. The researchers divided the participants into four groups. One group received no special treatment, serving as a baseline. The other three groups took sodium valproate for different lengths of time and at different strengths: one group took a moderate dose for just one to two weeks, another took the same moderate dose for four to six weeks, and the third took a higher dose for four to six weeks. The goal was to see which of these schedules was safe, which one patients could follow without stopping, and which one might actually reduce heart damage. The researchers monitored the patients closely, checking their blood for signs of liver stress or low platelet counts, and tracked whether they took every dose as prescribed.

The results revealed a clear pattern that surprised the team. The group that took the medication for the shortest time—one to two weeks—had the highest rate of success in sticking to the plan, with seventy percent of patients taking all their doses. In contrast, the groups asked to take the drug for longer periods or at higher doses struggled significantly, with many patients unable to continue due to side effects or the complexity of the regimen. When the researchers looked at the actual heart damage, measured by a protein released into the blood when heart cells are injured, they found that the short-term treatment group showed less damage than the others. The longer-term groups, however, did not show this benefit; in fact, they appeared to have more heart injury, suggesting that taking the drug for too long might actually make the heart more vulnerable.

To understand why this happened, the researchers took tiny samples of heart tissue from the patients during their operations and examined the cells with advanced technology that allows them to see how genes are turned on or off. They were initially looking for changes in the "openness" of the genetic code, a process where the drug might unlock certain genes to help the heart. Instead, they found that the drug's effect was not about unlocking genes in the way they expected. In the short-term group, the drug triggered a specific survival response in the heart cells. It activated a protective pathway involving a protein called p53, which helped the cells resist a type of cell death caused by oxidative stress. It also boosted a signaling system that acts like a shield against damage. These changes made the heart cells more resilient, preparing them to withstand the shock of surgery.

In the groups that took the drug for longer, the story was different. The protective signals faded, and the heart cells began to show signs of distress and a shift toward a state similar to heart failure. The cells started to lose their normal structure and began behaving in ways that made them more susceptible to injury. This suggested that while a short burst of the drug could act as a shield, keeping the body exposed to it for too long might wear down those defenses and leave the heart worse off than before. The researchers also confirmed these findings in a laboratory setting, where they treated heart cells with the drug and then subjected them to stress, observing the same protective effects only when the exposure was brief.

The study concludes that taking sodium valproate for a short period before heart surgery is safe and well-tolerated, and it appears to offer a genuine biological benefit by strengthening the heart's natural defenses. However, the protection is time-sensitive; extending the treatment beyond two weeks seems to reverse the benefits and increase the risk of injury. This finding is significant because it identifies a specific window where a common, inexpensive drug might be able to prevent a major complication of heart surgery. While the study was designed to test safety and feasibility rather than to prove the drug works as a cure, the consistent signals across patient data, tissue analysis, and lab experiments suggest that a short course of this medication could be a viable strategy for protecting the heart. The researchers emphasize that this is not yet a final solution, but a strong indication that the right dose, given for the right amount of time, could change how we prepare patients for the stress of cardiac surgery.