Volume Flow Rate Evaluation in Patients with Obstructive Arteriosclerotic Disease

Abstract

This study was performed to quantify the volumetric impact of extracranial arteriosclerotic lesions. We investigated patients with different degrees of carotid stenosis as defined by conventional velocity-based duplex criteria and different patterns of collateralization. We studied the volume flow rate (color duplex M-mode device) in 37 patients with symmetrical internal carotid artery (ICA) plaques (<50% stenosis) and compared these data to 43 patients with a unilateral 50–74% stenosis, 75–99% stenosis (n = 73) and occlusion of the ICA (n = 37). A 75–99% stenosis caused an ipsilateral flow reduction of 36% with a wide interindividual variability, and an occlusion of 51%. Collateralization via the ophthalmic artery only caused a nonsignificant ipsilateral volume flow increase, whereas the contralateral volume flow was significantly higher in patients with a patent anterior communicating artery. The increase was more pronounced in patients with an occluded vessel. Our data demonstrate a wide diversity of the hemodynamic impact of carotid stenosis as defined by ‘classical’ Doppler criteria. Collateral flow reflects a dynamic quantitative process.

Duplex ultrasound velocity criteria for the stented carotid artery

“…Contralateral carotid occlusion 25 and stenosis Ն50% 23 have been associated with increased carotid volume flow, 24 resulting in an overestimation of the severity of ipsilateral disease; however, we excluded all patients with known contralateral stenoses Ն50%.…”

“…The study excluded 39 patients who had contralateral carotid stenosis Ն50%, [23][24][25] leaving 216 patients with unilateral carotid stenosis. Completion CA or postprocedural DUS were not available or evaluable for 27 procedures, thereby providing 189 pairs of CA-DUS measurements for analysis.…”

Carotid Ultrasound Criteria for Detecting Intracranial Carotid Stenosis

“…Meyd et al [24] found that patients with high-grade stenosis had contralateral elevated flow compared with that of patients without high-grade stenosis and age-specific normal subjects (82.6% sensitivity). In the study performed by Doberenz et al [25], the impact of different degrees of extracranial carotid stenosis on the bilateral volume flow in the carotid arteries was evaluated. Patients with a high-grade stenosis (75–99%) or occlusion had a significantly reduced flow as compared with patients with stenosis <75%, but ipsilateral volume flow in patients with stenosis 50–74% only showed a slight, nonsignificant decline compared with that of patients with stenosis <50%.…”

Carotid Stenosis Assessed With a 4-Dimensional Semiautomated Doppler System

“…Given the well-known variability of volume flow estimation using conventional Doppler US,4, 15 time-domain correlation combined with a color M-mode technique5-8 as well as a new dual-beam, angle-independent Doppler device9-12 have been suggested as alternatives. While both methods (somewhat unrealistically) assume a circular symmetric velocity distribution, initial patient studies (involving 10 – 71 subjects) have been encouraging and have demonstrated the complex hemodynamic effects of carotid disease 7-8, 11-12.…”

“…While both methods (somewhat unrealistically) assume a circular symmetric velocity distribution, initial patient studies (involving 10 – 71 subjects) have been encouraging and have demonstrated the complex hemodynamic effects of carotid disease 7-8, 11-12. Studies of healthy volunteers to determine normal values on volume flow in the CCA and ICA have involved more subjects (205 and 77, respectively) and have shown an age-related decrease in flow.…”