Carotid angioplasty: The need to revise post surgical duplex velocity criteria

Abstract

Purpose. To determine the appropriate duplex velocities post carotid artery angioplasty and stent compared with endarterectomy for recurrent stenosis. Methods. Retrospective analysis on patients with over 80% recurrent carotid artery stenosis treated at our institution was performed. Velocities from preoperative, postoperative (<1 week), and late postoperative duplex scans (1–121 months) were compared after re-do carotid endarterectomy (CEA) or carotid artery angioplasty and stent (CAS) placement. Variables within the groups were compared using analysis of variance (ANOVA). Stepwise-regression analysis was used to determine the independence of CAS as a factor causing elevated postoperative velocities. Mean peak systolic velocities (PSV) ± SEM, end diastolic velocities (EDV) ± SEM, and internal carotid artery/common carotid artery PSV ratios (ICA/CCA) are reported. Results. Thirty-four patients with a mean age of 72 were studied. Sixteen patients underwent CAS, and 18 patients underwent CEA. The mean interval between first CEA and treatment for the recurrent stenosis (CEA or CAS) was 41 months. There was no significant difference in risk factors between groups (age, gender, patch, and contralateral occlusion). There was a significant difference in postoperative PSV between CEA and CAS, which resolved after 1.5 years. Similarly, the postoperative ICA/CCA was significantly different between CEA and CAS (0.97 ± 0.11 versus 1.48 ± 0.20, respectively, P < 0.05, ANOVA). When controlled for contralateral occlusion and interval (months) between procedures, CAS over CEA was found to be independently associated with elevated ICA/CCA ratios using linear regression analysis. Conclusion. Postoperative duplex velocities after CAS may not represent hemodynamic narrowing but may indicate altered biomechanics of the poststented carotid. TABLE—ABSTRACT 35 PSV (cm/s) EDV (cm/s) preop (n) postop (n) longterm (n) preop (n) postop (n) longterm (n) CEA 278 ± 38 102 ± 11 113 ± 12 90 ± 14 24 ± 4 28 ± 4 (18) (14) (12) (18) (14) (12) CAS 364 ± 47 ∗145 ± 18 116 ± 11 111 ± 15 30 ± 4 32 ± 3 (15) (17) (12) (15) (17) (12) Note. Mean ± SEM. ∗ P < 0.05 between CAS and CEA.