A study in this week's Circulation, the journal of the American Heart Association, shows for the first time that women have much the same survival rate as men following cardiac bypass surgery and angioplasty.

Previous studies suggested women were twice as likely to die as men.

The researchers believe the improvement in women's survival rates may show an increased awareness among doctors of the gender imbalance as well as the success of new technology.

The study of a random selection of 1,829 people undergoing bypass or angioplasty - 27% of whom were women - found similar death rates for men and women.

The women were on average three years older than the men and half were over 65 years old.

Around 1.3% of women died following bypass surgery, compared with 1.4% of men. Around 0.8% of women died after angioplasty, compared with 1.2% of men.

Five years after the operations, 87% of women and 88% of men were still alive.

Around 75% of women and 77% of men did not suffer another heart attack in the five years following surgery.

Gender issues

The researchers put their results, which are more impressive given that women tend to be weaker than men when they have heart operations, down to a number of factors.

These include advances in surgical technology and techniques, such as stents which prop open blood vessels following angioplasty operations.

Dr Alice Jacobs, who led the research, said: "Being aware of the issues that are specific to women also may have contributed to the better outcome."

But she also stated that the women in the random sample may have been different to women in the previous studies.

Women in the new study tended to be younger, have lower blood pressure, lower levels of cholesterol and more serious diseases than men, for example, diabetes.

"We cannot say for sure why the results are different," said Dr Jacobs.

"It's just an observation that they are different. We can recommend to women, with some enthusiasm, that they will have a reasonably good acute and long-term outcome."

Growing risk

Women used to suffer less from heart disease than men.

However, since the 1980s the numbers of American women with heart disease have been rising while for men the numbers were falling until the 1990s.

Experts differ about why this is. One factor could be women's ignorance about the risks and the impact of factors such as smoking and obesity.

Another could be that women are surviving longer after the protective effects of the menopause have worn off.