The Effect of Ipsilateral Carotid Revascularization on Contralateral Carotid Duplex Parameters in Patients with Bilateral Carotid Stenosis.

OBJECTIVE: Duplex-derived velocity measurements are often used to determine the need for carotid revascularization. There is evidence that severe ipsilateral carotid stenosis can cause artificially elevated velocities in the contralateral carotid artery, which may decrease following ipsilateral revascularization. The objective of this study was to determine if contralateral carotid artery duplex velocities decrease following ipsilateral carotid endarterectomy or stenting procedures.

METHODS: This is a single institutional retrospective study of prospectively collected data on all patients who underwent carotid revascularization from 2013 to 2021. Patients with immediate preoperative and first postoperative Duplex scan within four months of carotid revascularization at our vascular laboratory were included for analysis. Patients with contralateral occlusion were excluded. Duplex criteria used to define moderate (50% to 69%) and severe (>70%) stenosis was systolic velocity ≥ 125 cm/sec and ≥ 230 cm/sec, respectively.

RESULTS: Between 2013-2021, 129 patients with bilateral carotid stenosis underwent either carotid endarterectomy (98) or a stenting procedure (31). The majority of patients (90%) underwent intervention for severe stenosis. Preoperatively, the contralateral artery was categorized as severe in 30.4% patients. After ipsilateral carotid revascularization, 86 patients (67.2%) saw a decrease in the contralateral artery PSV while the remaining remained stable or increased. Fifty-four patients had a change in designated stenosis severity in the contralateral artery. Between the CEA and stenting cohorts, there was no significant difference in the proportion of patients whose contralateral velocity decreased (69.4% vs 61.3%, p = .402). Patients with coronary artery disease and diabetes were significantly less likely to experience a decrease in the contralateral artery PSV after ipsilateral intervention (p =.018 and p = .033).

CONCLUSIONS: In patients with bilateral carotid disease, ipsilateral revascularization can change the contralateral artery velocity and perceived disease severity. Most patients were noted to have a decrease in the contralateral artery PSV, although almost one-third either stayed stable or increased. On multivariable analysis, patients with coronary artery disease and diabetes were less likely to see a decrease in the contralateral artery PSV. Patients who are at risk for artificial elevation of the contralateral artery, may warrant a re-evaluation of the contralateral artery after ipsilateral intervention. These patients may be better assessed with axial imaging, although further research is needed.