Severe bilateral carotid stenosis: the impact of ipsilateral stenting on Doppler-defined contralateral stenosis

Abstract

Objectives: The study examined the effect of carotid stenting (CS) on contralateral carotid Doppler-defined degree of stenosis.

Background: Patients with carotid disease are frequently referred for carotid revascularization (carotid endarterectomy [CEA] or CS) based on the results of carotid duplex studies. Although a drop in flow velocities in the contralateral carotid has been described after CEA, the effect of ipsilateral stenting on contralateral velocities has not been defined.

Methods: A total of 104 consecutive patients underwent CS and were divided into two cohorts, those with unilateral stenosis, and those with bilateral stenosis. Doppler-defined pre-procedural peak systolic velocities (PSV) and end-diastolic velocities (EDV) in the contralateral carotid were compared with the post-procedural velocities. Post-procedural angiographic stenoses were compared with post-procedural duplex-defined stenoses.

Results: Among patients with bilateral stenosis, after ipsilateral stenting there was a drop in the contralateral PSV and EDV of 60.3 cm/s (p = 0.005) and 15.1 cm/s (p = 0.03), respectively. There was no change in the contralateral velocities in patients with unilateral stenosis. Among patients with > or =60% stenosis by duplex in the contralateral carotid, 20% dropped to a lower classification of contralateral stenosis after ipsilateral stenting. Furthermore, 71% of patients with significant contralateral stenosis by duplex pre-stenting did not have significant stenosis by angiography.

Conclusions: Patients with bilateral carotid disease may have elevated Doppler flow velocities in the contralateral carotid resulting in an artifactually high grade of stenosis. After ipsilateral carotid revascularization, such patients should have a repeat Doppler of the contralateral carotid to assess the true grade of stenosis.