PHILADELPHIA — Both carotid artery stenting and carotid endarterectomy produced a roughly 50% increase in overall cognitive function in a study of 46 patients undergoing intervention for asymptomatic severe carotid stenosis.
The change was big enough to significantly improve the patients' quality of life. But both revascularization methods also had a price: Carotid stenting resulted in a clinically significant deterioration in average psychomotor speed, and carotid endarterectomy produced a clinically significant decrease in average memory.
The unexpected finding raised questions about how two methods of carotid revascularization produce two different sets of cognitive outcomes. “We were very surprised by the results,” Dr. Brajesh K. Lal said at the annual meeting of the Eastern Vascular Society.
“There is a lot to understand about the travel of microparticles, which may selectively affect different parts of the brain.” That is just one possible explanation for the finding. Stenting and endarterectomy differ in arterial clamping, balloon placement, stenting, dissection, and hypoperfusion, any of which could play a role. “We hypothesize multiple mechanisms by which carotid endarterectomy and stenting produce cognitive dysfunction,” said Dr. Lal, a vascular surgeon at the University of Maryland. Baltimore.
The study administered six cognitive tests to 46 asymptomatic patients with unilateral carotid stenosis of 70% or more who were scheduled to undergo revascularization. Patients took 50 minutes to complete the panel of tests before surgery and again at 4-6 months after treatment. The tests measured memory, attention, psychomotor speed, motor speed/coordination, learning, and fluency.
Of the 46 patients, 25 had endarterectomy and 21 had stenting. Just over half the patients in each group had right-sided stenosis, and there were no significant clinical differences between the groups at baseline.
About 6 months after treatment, the composite score rose by an average of 0.47 for the stented patients, compared with baseline, and by 0.51 for the endarterectomy patients.
The cognitive changes, scored on a scale of 0-1.0, showed that the two groups weren't significantly different, but the increases in both groups were very clinically meaningful.
In the stented group, all individual cognitive scores rose by 0.46 or greater, except for psychomotor speed, which fell by a third after stenting (see table). In the open surgery group, all domains rose by 0.58 or better except memory, which dropped by 0.41.
The same panel of cognitive tests should be used on similar patients managed medically to gauge the cognitive effect of treatment, Dr. Lal said.
There are many mechanisms by which carotid endarterectomy and stenting may produce cognitive dysfunction.
Source Dr. Lal
Source Elsevier Global Medical News