Objective: Patients with internal carotid artery (ICA) occlusion or severe stenosis usually have collateral via ophthalmic artery (OA). However, the relationship of blood flow patterns of OA and the degree of ICA stenosis has been rarely reported. Transcranial Doppler (TCD) is a promising modality to assess OA collateral when ICA lesion. Considered OA characteristics including tortuosity and anatomical variations, we try to evaluate the supraorbital artery (SA), the one of OA terminal branches, to analyze the relationship of flow with the degree of ICA stenosis.
Materials and Methods: From Jun 2012 to Jan 2015, TCD were performed to 40 patients with ICA stenosis before and after carotid artery stenting (CAS). SA blood flow patterns were compared with the degree of ICA stenosis confirmed by conventional angiography.
Results: 40 patients (29 men) were enrolled (mean age 64.9 yrs). Before CAS, the retrograde blood of SA was found in 40 patients. After stenting, the flow pattern reversed in 29 patients of these patients (29/40, 72.5%). The blood flow of SA was gradually reverse over time from angioplasty with balloon to several days after CAS. The patterns of these changes were categorized into four types: (A), flow spectrum completely reversed; (B), reverse flow spectrum associated with systolic notch; (C), flow spectrum forward at systolic and reverse at diastolic; (D), type flow spectrum entirely forward. Before balloon angioplasty (mean stenosis, 93.4%), A type was found in 39 of them, B type in 1 patient; after balloon dilatation (mean stenosis, 82.9%), 26 A types and 4 B, 5 C, 5 D types. Stent (mean stenosis, 14.9%), 1 A type, 4 B and 4 C, 29 D types.
Conclusion: The flood flow patterns of SA may be associated with the degree of carotid stenosis evaluated with TCD and the blood flow may be reverse after CAS.
This work was supported by the National Natural Science Foundation of China (Contractgrant number: 81471390 to N.M).