http://bmj.com/cgi/content/full/324/7336/504/a
BMJ 2002;324:504 ( 2 March )
David Spurgeon Quebec
Women have as much as a three times higher risk than men of dying during or shortly
after coronary artery bypass surgery, even though their coronary
atherosclerosis may be less extensive and their heart pumping action may be
better, a US study shows (Circulation 2002;105:1176-81).
Authors of the study, led by Dr Viola Vaccarino of Emory University in
Atlanta, Georgia, reviewed records of 51 187 patients in the National
Cardiovascular Network database who underwent cardiac bypass surgery at 23
medical centres between October 1993 and December 1999. Thirty per cent (15
178) of these were women.
The study is the first to examine specifically whether younger women have a
higher inhospital mortality risk than men after cardiac bypass surgery, the
authors state. The younger women had more comorbid conditions and risk
factors—particularly diabetes—and more angina, compared with men, and a
distinctly higher risk of postoperative renal failure. They also had higher
rates of neurological complications and acute myocardial infarcts after the
procedure. But when pre-existing conditions and risk factors were accounted
for, they explained less than a third of the mortality difference between women
and men at younger ages.
"The younger the patients, the greater the mortality difference between
women and men," said Dr Vaccarino, associate professor of medicine at
Emory’s medical school and associate professor of epidemiology at its Rollins
School of Public Health. She could not explain this difference.
"In all age groups, women had less severe coronary artery disease and
higher left ventricular ejection fraction and had less often a prior history of
MI [myocardial infarction] or CABG [coronary artery bypass graft] compared with
men," said the study.
"It seems paradoxical, but that’s what the data show," said Dr
Vaccarino. "Clearly, we need further investigation in order to determine
the causes for these mortality differences."
The research team divided the study patients into five age groups—younger
than 50, 50-59, 60-69, 70-79, and 80 or older. Overall, 5.3% of the women in
the study died in hospital compared with 2.9% of the men.
In subjects younger than 50, 3.4% of women died compared with 1.1% of men,
whereas in the 50-59 age group, 2.6% of the women died compared with 1.1% of
the men. Mortality differences declined with age. Among bypass patients aged 80
or older, risk of death was only slightly greater for women (9.0%) than for men
(8.3%).
The number of women patients undergoing cardiac bypass surgery is increasing
in the United States, said the study. In 1998, 28% of the 550 000 procedures performed
were in women. But it has not yet been determined whether women benefit from
the procedure to the same extent as men.
Major randomised trials of the efficacy of bypass surgery
compared with medical treatment have comprised either only men or predominantly
men. And observational studies comparing outcomes between the sexes have
provided conflicting results.
ALL INFORMATION, DATA,
AND MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION
PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR
OPINIONS OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING
MEDICAL OR LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN
IMPORTANT AND COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN
CONSULTATION WITH YOUR HEALTH CARE PROVIDER.