Abstract 17178: Rates of Micro Embolic Signals at Different Stages of Carotid Artery Revascularization

Abstract

Background: The American Heart Association currently estimates that over 160,000 people die every year due to new or recurrent strokes, many from carotid artery stenosis. This association has led to increased use of carotid revascularization procedures such as carotid endarterectomy (CEA) and carotid artery stenting (CAS). In this study we aim to describe the different rates of micro embolic signals (MES) at different stages of carotid artery revascularization. Methods: Before elective carotid revascularization 57 patients (mean age 72±8 years; 15 males, 21 females) underwent 3-T MRI. After localization of the carotid bifurcation using phase contrast imaging, Time-of-Flight, 3D T1 weighting, transverse T1 and T2 weightings and proton density sequences were acquired. The different plaque components: lipid core, intraplaque hemorrhage, calcification and the characterization of the fibrous cap were assessed. While 34 patients underwent CEA, 20 patients had CAS. CES was divided into 9 stages: 1- Pre-procedure, 2- Dissection, 3- IC clamp, 4- Shunt placement, 5- Shunt open, 6- Endarterectomy, 7- Clamped, 8- IC opened, 9- Post-procedure. Similarly, CAS was divided into 9 stages: 1- Pre-procedure, 2- Arch-carotid angiography, 3- Wire insertion, 4- Filter deployment, 5- Pre-dilation, 6- Stent deployment, 7- Post-dilation, 8- Final angiography, 9- Post-procedure. Patients were monitored continuously with transcranial doppler (TCD) to detect pre-procedural, intra-procedural and post-procedural MES rates. Results: MES was detected in 20 (87%) patients undergoing CAS compared to 18 (53%) patients undergoing CES during the IC Clamp/Wire Insertion stage (p=0.004). Greater mean micro embolic signals were also found in symptomatic patients undergoing CAS than in asymptomatic patients during arch-carotid angiography (10.8 vs 2.4, p= 0.022), post-dilation (3.1 vs 1.1, p=0.047), and post-procedure (4.8 vs 1.3, p=0.044). Conclusion: MES is increased during the wire insertion stage of CAS in addition to post-dilation and post-procedure stages. Also, the finding of increased MES during arch-carotid angiography suggests that less invasive alternatives to diagnostic angiography should be considered in symptomatic patients.