DOCTORS have defended an increase in deaths for some types of heart surgery and insisted treatment was improving for patients.

The death rate for aortic valve replacements, or AVR, where surgeons replace a diseased valve with an artificial or tissue valve, increased from 1.5 per cent in 2002 to 2003, to 3.25 per cent in 2007 to 2008.

But figures released by the John Radcliffe Hospital also showed a drop in mortality rates for heart bypass surgery.

Cardiac surgeon Prof Stephen Westaby, who has worked at the John Radcliffe for more than 20 years, said the apparent increase in deaths in AVR surgery could be explained by the number of high risk patients being taken on.

He said: “These statistical issues are never what they seem. In the case of primary aortic valve replacements, we are now doing patients in their late 80s and 90s.

“We are now looking at an extremely elderly group of patients and you simply can’t keep mortality rates down.

“The figure of 3.25 per cent is still very, very low for the sort of groups we are dealing with. The John Radcliffe is known in the country to take on a proportion of high risk patients.”

Prof Westaby pointed out deaths in primary coronary artery bypass grafting, or CABG, fell from 4.15 per cent in 2002 to 2003 to 2.24 per cent last year.

A spokesman for the hospital said: “There are a number of reasons why cardiac surgery outcomes have improved over time, including a better understanding of individual patients’ risks, the sharing by surgical teams of the latest techniques, and improvements in intensive care.

“This having been said, no group of patients from one year will be identical to a group of patients from another year, and the risk for each patient still needs to be considered on an individual basis, for example in any one year you may have more or fewer high risk patients.”