FDA approves MEA system for excessive bleeding: microwave endometrial ablation: patients must have an endometrial thickness of at least 10 mm to undergo the procedure.(News)

The Food and Drug Administration imposed conditions on its recent approval of a microwave endometrial ablation system that have "significantly minimized the potential for an adverse event," according to Dr. Jay Cooper, principal investigator of the U.S. trial on which the approval was based.

Patients who are being considered for treatment with the microwave endometrial ablation (MEA) system must undergo a screening ultrasound to determine endometrial thickness. Women must have an endometrial thickness of at least 10 mm to be considered for the procedure, the FDA noted in the approval.

Patients also must undergo intraoperative hysteroscopy to ensure uterine integrity, the FDA said. The system, approved in late September and marketed by Microsulis Americas Inc. in Westford, Mass., is indicated for treatment of excessive menstrual bleeding due to benign causes in premenopausal women who have completed childbearing.

The device is already approved in the United Kingdom, Canada, and Australia. In these countries, endometrial thickness must be at least 8 mm rather than 10 mm, as required by the FDA, said Dr. Cooper, a gynecologist and medical director at Women's Health Research in Phoenix, a free-standing clinical trials facility.

"The FDA had suggested that they were uncomfortable with the 8-mm requirement, so the company proposed 10 mm," noted Dr. Cooper, who said he had no financial interest in Microsulis or the MEA system.

The 8-mm cutoff had been used in the randomized, controlled U.S. trial of the device, which included 324 patients. Although there were no serious adverse events in that trial, there were 27 cases of uterine perforation and/or transmural thermal injury to the bowel when the MEA was first approved more than 7 years ago in the United Kingdom, Canada, and Australia. Twenty-four of those cases required bowel resection.

"I don't think the technology was introduced with the requisite training and requirements in some of those countries," he said, adding that there have been no additional adverse events in the three countries since stricter ultrasound and hysteroscopy requirements were introduced there 2 years ago.