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Home > Vascular Annual Meeting > RR6. Long-Term Outcomes and Predictors...

RR6. Long-Term Outcomes and Predictors of Microemboli Following Carotid Interventions

Wei Zhou, Rosa Zareie, David Dinishak, Maureen Tedesco, Barton Lane, Fritz Bech, Ronald Dalman, Allyson Rosen
Stanford University, Stanford, CA

OBJECTIVES: Significant numbers of microemboli on diffusion-weighted magnetic resonance imaging (DWI) have been identified immediately following carotid stenting procedures (CAS), but the clinical significance of these microemboli is largely unknown. This study was to evaluate long-term outcomes and risk factors predictive of microemboli following CAS.

METHODS: Patients who underwent perioperative MRI evaluations for carotid interventions at a single institution from 7/2004 to 12/2008 were evaluated, particularly those who had additional follow-up MRI. DWI with apparent diffusion coefficient (ADC), FLAIR, and T2W MRI images were compared to determine long-term effect of microemboli. Risk factors including patient demographic, clinical symptoms, lesion characteristics, and perioperative hemodynamic status were analyzed using a Cox regression model, in a stepwise procedure.

RESULTS: One-hundred sixty-eight consecutive patients (68 CAS and 100 CEA) who received perioperative MRI were included. The incidence of microemboli was significantly higher in CAS group than CEA group (46.3% and 12% respectively, p<0.05) despite a relative low incidence of associated neurologic symptoms (2.6 % vs. 2%). Thirty patients (16 CAS and 14 CEA) with 50 DWI lesions (mean size 46.57 mm2, ranging 16 to 128mm2) were further analyzed. During a mean MRI follow-up of 10 months (range, 2 to 23 months), residual MRI abnormalities were only identified in DWI lesions larger than 60 mm2 (n=5, p<0.001). CEA group had fewer but larger ipsilaterally distributed emboli (total 12 lesions, mean 79 mm2) comparing to CAS group (total 38 lesions, mean 27.5 mm2, p<0.05). Regression analyses of 68 CAS patients (mean age 71 years, range, 53-91 years) showed that date of procedure prior to 1/2007, coronary artery disease, diabetes, and perioperative troponin elevation were significant predictors of microemboli (p<0.03). Date of procedure was the only predictor of bilateral hemispheres microemboli (p=0.025).

CONCLUSIONS: Carotid interventions are associated with significant DWI lesions despite absence of clinical symptoms. Risks of microemboli correlate to physician experience and patient selection. Larger DWI lesions (>60 mm2) can lead to long-term residual structure abnormalities that warrants further neurocognitive evaluation.

AUTHOR DISCLOSURES: W. Zhou, None; R. Zareie, None; D. Dinishak, None; M. Tedesco, None; B. Lane, None; F. Bech, None; R. Dalman, None; A. Rosen, None.