Health library

Jan. 21, 2019—Heart bypass surgery can be a lifesaving treatment option for many people who have blocked or narrowed arteries. It helps restore blood flow to the heart by using a healthy artery or vein to go around the blocked portion. While the results are often very good, the surgery does have risks. Among them, it's often blamed for a loss of memory and thinking skills, known as postoperative cognitive decline (POCD).

But researchers wondered: Is the surgery really to blame? Or are there other factors at work?

To answer those questions, they looked at data from 3,105 seniors who were divided into two groups. One group had heart surgery, such as bypass. The other group had cardiac catheterization, a less invasive procedure. With this technique, a thin tube (catheter) is inserted into a blood vessel. Through the catheter, doctors can widen a narrowed artery with a small balloon or even prop it open with a mesh tube called a stent.

Both groups took memory tests up to two years after their heart procedure.

Subtle changes, if any

According to the findings, those who had heart surgery did not appear to have major memory problems as a result. The changes seen in their cognitive skills before and after surgery were small. What's more, those changes were very similar to those seen in the people who'd had the much less invasive catheter procedure.

The researchers concluded that any effects from heart surgery on memory or thinking—if they occur at all—are likely to be subtle. For example, a 75-year-old person might see:

• A 0.26 percent decrease in the ability to manage finances without help.
• A 0.19 percent decrease in the ability to manage medications without help.

Memory problems are real

So why have other reports linked heart surgery to thinking or memory problems? The authors think that severe heart disease, in and of itself, probably affects these skills. But their findings suggest that the surgery isn't to blame.

POCD tends to occur more often in older adults. And it may be related to other factors that occur after surgery, most of which are temporary, like the effects of pain medicines. That's why this study's approach of tracking surgery patients for up to two years into their recovery is an important way to look at POCD, one of the researchers noted.

The study appears in the journal The Annals of Thoracic Surgery. Read more about the findings.