Study Indicates Cognitive Impairment in Otherwise Asymptomatic Carotid Stenosis Patients
October 4, 2017—The Society for Vascular Surgery (SVS) announced the publication of a study showing that approximately half of asymptomatic carotid stenosis patients had mild to moderate cognitive impairment. Brakesh K. Lal, MD, et al published the findings in SVS's Journal of Vascular Surgery (2017;66:1083–1092).
According to SVS, the study clarifies the role of asymptomatic carotid stenosis independent of cerebral-vascular risk factors in the development of cognitive impairment and suggests hemodynamic impairment as a possible mechanism for this important finding.
Dr. Lal led investigators from the University of Maryland and the Baltimore Veterans Affairs Medical Center in Baltimore, Maryland, who performed a prospective controlled trial to address the role of carotid stenosis in cognitive impairment and offer a potential mechanism for its effect.
The investigators studied 82 patients who did not have history of cerebral or retinal ischemic symptoms but had > 50% carotid stenosis by duplex imaging. The 62 control patients were also asymptomatic, without carotid stenosis, and subsequently matched for vascular comorbidities.
After administering neurologic tests and a transcranial doppler examination (including a 30-second breath hold to determine cerebral vasoreactivity), the investigators found that patients with carotid stenosis had an overall decrease in cognitive scores including learning, motor, and executive functions compared to controls. Additionally, 49.9% of patients with stenosis were considered mildly or moderately impaired compared to 22.6% in the control; 50% of patients with stenosis had impaired cerebral-vascular hemodynamics, all of whom had cognitive impairment. There were no significant differences in microembolic events between the two groups and no correlation between cognition and plaque burden itself.
In the SVS announcement, Dr. Lal commented, “This study found evidence that cognitive impairment is an under-recognized morbidity in patients with otherwise asymptomatic carotid stenosis. It is an important clinical outcome that must be included as a defined endpoint in future trials testing the efficacy of treatment strategies for carotid stenosis.” Regarding the finding that the mechanism is likely hemodynamic in origin, he added, “These findings prompt additional studies to evaluate if revascularization can reverse this impairment by improving cerebrovascular hemodynamics.”
Neurologic testing and hemodynamic evaluation of cerebral perfusion might provide clinicians with additional tools to refine treatment protocols currently based on symptoms and degree of stenosis alone. This appears to be a big step toward personalized medicine in cerebral vascular disease, noted SVS in the announcement.