Stenting's Steep Learning Curve Linked to High Mortality Rates

Physicians who have little experience with technically demanding carotid artery stenting have alarmingly higher rates of 30-day mortality than more seasoned operators, according to a study that reviewed 24,701 procedures in Medicare beneficiaries.

Additionally, more than 70% of the operators performed fewer than six procedures annually, a level of experience associated with the highest, 2.5%, risk of patient death.

Patients of operators who performed 6 to 11 procedures a year had a 1.9% 30-day mortality, 12-23 procedures had a 1.6% mortality and patients of operators with 24 or more procedures had a 1.4% mortality, indicating a treacherous learning curve at the patient's expense.

For some reason, novice operators were less likely to use an embolic protection device, which is a filter or balloon placed inside the artery to prevent particles from escaping and causing neurological damage.

The report by Brahmajee K. Nallamothu, MD, of the University of Michigan Medical School in Ann Arbor was published Wednesday in the Journal of the American Medical Association.

"Overall, 461 patients (1.9%) died within 30 days of their procedure and 1,173 patients (4.8%) did not receive an embolic protection device," the Nallamothu and colleagues wrote. "We identified an additional factor that may be contributing (to higher rates of 30-day mortality): limited operator experience with carotid stenting as the procedure has disseminated into routine clinical practice.

"Indeed, we found that fewer than 1 in 8 operators had annual operator volumes of 12 procedures or more during the study period."