How Kidney Function Affects the Heart

Small kidney function changes may affect heart, blood vessels

(RxWiki News) Although they're not connected directly, your kidneys may still affect your heart.

That's the message from a new study from researchers in the United Kingdom. This study found that kidney donors — who are otherwise very healthy individuals — developed small changes in heart function after donation. The changes indicated that the heart and blood vessels were damaged by a decrease in kidney function.

"Even in very healthy people, a small reduction in kidney function from normal to just a bit below normal was associated with an increase in the mass of the left ventricle, a change that makes the heart stiffer and impairs its ability to contract,” said senior study author Jonathan Townend, MD, a professor of cardiology at the Queen Elizabeth Hospital Birmingham Edgbaston in the UK.

Medical professionals have long known that people with chronic kidney disease have a raised risk of heart disease. Since chronic kidney disease typically exists with other heart disease risk factors like diabetes and high blood pressure, it was hard to determine the effect of kidney function on the risk of developing heart disease.

Once the kidneys fail, a kidney transplant from a healthy person is one possible treatment strategy. Dr. Townend and colleagues studied 68 kidney donors for the first year after surgery and compared them to 56 patients who were healthy and had not donated a kidney.

Kidney function in the donors declined slightly, while the mass (size) of the left ventricle in the heart increased slightly and blood tests showed a slight increase in heart damage, Dr. Townend and team found. The healthy controls did not show these changes.

Dr. Townend stressed that these changes were very minor and difficult to detect, so the risk to the kidney donor is likely small.

"This is evidence that reduction in kidney function itself leads directly to measurable adverse effects on the heart and blood vessels, even without other risk factors," Dr. Townend said. "More research is needed to know just what aspects of reduced kidney function are responsible for the effects. Even if there is a small increase in your long-term risk of heart disease after donation, it is still likely that you will be at lower than average risk.”

If tests indicate reduced kidney function, patients should talk to their doctors about ways to decrease heart disease risk, Dr. Townend and colleagues said.

This study was published Jan. 11 in the journal Hypertension.

The British Heart Foundation, the National Institute for Health Research/Wellcome Trust and Queen Elizabeth Hospital Birmingham funded this research. The authors disclosed no conflicts of interest.

Review Date: 
January 12, 2016