The chances of dying after heart surgery seem to be higher for people who are on the short side than for taller people, Argentine researchers report.

“The risk of dying in the hospital (after a heart bypass) increases by 30 percent for every reduction of 10 cm (4 inches) in height,” said lead investigator Dr. Marcelo Trivi of the Buenos Aires Cardiovascular Institute during the Argentine Congress of Cardiology here.

Trivi’s team analyzed the 1-month outcome of 2475 men and women who underwent coronary bypass surgery in 12 Argentinian centers.

After dividing patients into four height categories, the doctors found mortality rates went up as height went down. For patients who were less than 1.59 meters (5 feet 2 inches) in height, the in-hospital mortality risk was 2.5 times higher than for their taller counterparts, authors said.

“If you have to operate on a very short patient, you should evaluate carefully the risk-benefit ratio,” Trivi told Reuters Health. Short height might make a less invasive intervention, such as drugs or coronary angioplasty, a better option than bypass surgery.

Reasons for the link remain unknown, but the researchers noted that height (not weight) is strongly related to heart size. “The shorter you are, the smaller your heart and coronary arteries. And this must have an influence on the by-pass surgery outcome,” Trivi said.