title: Volume of subclinical embolic infarct correlates to long-term cognitive changes after carotid revascularization.
abstract: Carotid intervention is safe and effective in stroke prevention in appropriately selected patients. Despite minimal neurologic complications, procedure-related subclinical microemboli are common and their cognitive effects are largely unknown. In this prospective longitudinal study, we sought to determine long-term cognitive effects of embolic infarcts.
  
  
  
  The study recruited 119 patients including 46% symptomatic patients who underwent carotid revascularization. Neuropsychological testing was administered preoperatively and at 1 month, 6 months, and 12 months postoperatively. Rey Auditory Verbal Learning Test (RAVLT) was the primary cognitive measure with parallel forms to avoid practice effect. All patients also received 3T brain magnetic resonance imaging with a diffusion-weighted imaging (DWI) sequence preoperatively and within 48 hours postoperatively to identify procedure-related new embolic lesions. Each DWI lesion was manually traced and input into a neuroimaging program to define volume. Embolic infarct volumes were correlated with cognitive measures. Regression models were used to identify relationships between infarct volumes and cognitive measures.
  
  
  
  A total of 587 DWI lesions were identified on 3T magnetic resonance imaging in 81.7% of carotid artery stenting (CAS) and 36.4% of carotid endarterectomy patients with a total volume of 29,327 mm3. Among them, 54 DWI lesions were found in carotid endarterectomy patients and 533 in the CAS patients. Four patients had transient postoperative neurologic symptoms and one had a stroke. CAS was an independent predictor of embolic infarction (odds ratio, 6.6 [2.1-20.4]; P < .01) and infarct volume (P = .004). Diabetes and contralateral carotid severe stenosis or occlusion had a trend of positive association with infarct volume, whereas systolic blood pressure ≥140 mm Hg had a negative association (P = .1, .09, and .1, respectively). There was a trend of improved RAVLT scores overall after carotid revascularization. Significantly higher infarct volumes were observed among those with RAVLT decline. Within the CAS cohort, infarct volume was negatively correlated with short- and long-term RAVLT changes (P < .05).
  
  
  
  Cognitive assessment of procedure-related subclinical microemboli is challenging. Volumes of embolic infarct correlate with long-term cognitive changes, suggesting that microembolization should be considered a surrogate measure for carotid disease management.
authors.affiliation: Vascular Surgery, VA Palo Alto Health Care System, Palo Alto, Calif; Department of Surgery, Stanford University, Stanford, Calif. Electronic address: weizhou@stanford.edu.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Vascular Surgery, VA Palo Alto Health Care System, Palo Alto, Calif.
authors.forename: Brittanie D
authors.initials: BD
authors.lastname: Baughman
authors.affiliation: Department of Radiology, Harvard Medical School, Cambridge, Mass.
authors.forename: Salil
authors.initials: S
authors.lastname: Soman
authors.affiliation: Department of Radiology, Stanford University, Stanford, Calif.
authors.forename: Max
authors.initials: M
authors.lastname: Wintermark
authors.affiliation: Department of Psychiatry and Behavior Science, Stanford University, Stanford, Calif.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Lazzeroni
authors.affiliation: Vascular Surgery, VA Palo Alto Health Care System, Palo Alto, Calif.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hitchner
authors.affiliation: Department of Psychiatry, VA Palo Alto Health Care System, Palo Alto, Calif.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Bhat
authors.affiliation: Department of Psychiatry and Behavior Science, Stanford University, Stanford, Calif; Department of Psychiatry, VA Palo Alto Health Care System, Palo Alto, Calif.
authors.forename: Allyson
authors.initials: A
authors.lastname: Rosen
mesh_terms: D000368:Aged; D017130:Angioplasty / Q000009:adverse effects* / Q000295:instrumentation; D016893:Carotid Stenosis / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*; D002544:Cerebral Infarction / Q000000981:diagnostic imaging / Q000209:etiology*; D016009:Chi-Square Distribution; D003071:Cognition; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology* / Q000523:psychology; D038524:Diffusion Magnetic Resonance Imaging; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging / Q000209:etiology*; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome