Transcranial Doppler detects micro emboli in patients with asymptomatic carotid stenoses undergoing endarterectomy

Abstract

Objective: The objective of this study was to assess the primary endpoint defined as the detection of micro-embolic signals (MES) by the use of transcranial Doppler (TCD) in patients with asymptomatic carotid stenosis (≥70%) scheduled for carotid endarterectomy. The secondary endpoint consisted of testing the association of MES with stenosis severity, histopathological, and ultrasound characteristics.

Methods: This was a single-center, single-arm, prospective, observational trial. Computed tomography angiography and ultrasound assessment (Geroulakos classification) were mandatory as well as being under best medical therapy. MES number and characteristics were investigated in Holter mode TCD-X device with a standard 1.5 MHz probe. The time points of evaluation were: 24 hours preoperative, 24 hours postoperative, and 30 days postoperative. The histopathological analysis was performed according to the modified American Heart Association classification. One-way analysis of variance tested MES differences over time. Univariable and multivariable logistic regression tested variables potentially associated with MES.

Results: A total of 120 patients demonstrated a significant reduction of the mean number of MES (3.35 ± 10.04 and 0.82 ± 2.39; pre- and post-carotid endarterectomy, respectively), becoming undetectable at 30 days (P = .001). Hypoechogenic plaques assessed by ultrasound were a significant risk factor for MES (P = .001). The features of plaque vulnerability, such as hemorrhagic component (P = .011), neovascularization (P = .025), signs of inflammation (P = .027), and rupture of the fibrous cap (P = .002) were predictors of MES. Cap rupture was the only predictor in the multivariate analysis (odds ratio, 5.98; P = .030). The stenosis severity was not associated with MES (P = .95) CONCLUSIONS: Patients under best medical therapy had a preoperative embolic activity becoming no more detectable after surgery. Both ultrasound and histologic markers of vulnerability were predictors of MES, and stenosis severity was not associated. TCD gives better insight into the real embolic risk, and future studies should evaluate clinical results coming from its implementation with standard imaging techniques.

Clinicaltrial: gov registration number NCT05134493.

Keywords: Carotid stenosis; Embolic risk; Endarterectomy; Micro-embolic signals; Transcranial Doppler.