November 8, 2007–ORLANDO–Women have nearly a 70 percent greater risk of suffering major in-hospital complications than men after implantation of a cardioverter-defibrillator, researchers reported here.
“We found that major complications occurred about 1.1 percent of the time in men and 2 percent of the time in women," Pamela Peterson, M.D., of the Denver Health Medical Center and the University of Colorado, told attendees at the American Heart Association meeting.
That represents about a 69% increased risk, a statistically significant difference, she said.
The major complications included cardiac arrest, perforation of the heart, heart valve injury, coronary venous dissection, hemothorax, pneumothorax, deep phlebitis, transient ischemic attack or stroke, tamponade, myocardial infarction and arteriovenous fistula.
“We really don't know why women have more problems with these devices than men,” said Dr. Peterson. “However, we do speculate that part of the problem may be that women have a smaller body size.”
Dr. Peterson and colleagues analyzed data accrued by the National Cardiovascular Data Registry from January 2005 through April 2007, identifying 59,833 individuals undergoing first-time implantation of the defibrillators for primary prevention of sudden cardiac death. The study included 43,574 men and 16,079 women.
Not only were women more likely to suffer major complications, they were more likely to suffer any adverse event. That rate was 3.6 percent for men and 4.6 percent for women, representing a 29 percent increased risk by sex, also a significant finding, Dr. Peterson reported. The figures were adjusted for clinical differences between men and women.
“These results should not preclude women from receiving implantable cardioverter-defibrillators,” Dr. Peterson said. “However, the reason for higher adverse event rates should be investigated and, where possible, eliminated.”
The authors did point out that, “as complications attenuate the benefits that might accrue from ICD therapy, the higher risk of complications may influence the decision to implant a device in women.”
“I think the reason for the increased risk among women is due to body size,” said Nieca Goldberg, M.D., director of the New York University Women's Health Program, who moderated the session. She said that problems existed in angioplasty procedures as well until manufacturers began developing smaller-sized devices that were more fitted to a woman's anatomy.
“There are manufacturers that are also producing smaller implantable defibrillators as well, and this may benefit women by reducing some of the problems caused by anatomy,” she said.