Study on correlation between retinal vessel morphology or ocular hemodynamic parameter and internal carotid artery stenosis

Objective: To analyze the correlation between retinal vascular calibers, ocular blood flow parameters and internal carotid artery stenosis and to evaluate the effect of internal carotid artery stenosis on ocular blood vessels comprehensively. Methods: A retrospective case-control study. The clinical data of 141 patients who underwent head-and-neck computed tomography (CT) angiography examinations of the ICA were collected at Beijing Friendship Hospital, Capital Medical University from January 2014 to January 2016. According to diagnostic criteria, the patients were divided into four groups: the non-stenosis group, the mild stenosis group, the moderate stenosis group, and the severe stenosis andocclusion group. The retinal vascular caliber was measured in color fundus photograph by IVAN software. Color Doppler ultrasonography was used to measure the parameters of ocular blood flow, including the peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI). The enumeration data were analyzed with chi-square test, the measurement data were analyzed with rank-sum test, and the correlation test was performed with spearman. Results: The gender ratio of the patients without stenosis, mild stenosis, moderate stenosis, severe stenosis and occlusion was 12/7, 31/19, 28/25, 12/7, χ2 test was not statistically significant (χ2= 0.79, P=0.85); There was no statistically significant difference between the different groups (χ2= 0.15, P=0.68), the age of four groups were (64.1±8.3), (54.3±14.3), (68.9±11.8) and (59.1±8.0) y, respectively. In the no internal carotid artery stenosis group, the arteries diameter is (164.5±15.6) μm ,the vein diameter is (245.6±20.0) μm and the arteriovenous ratio is 0.7±0.1. There is no difference among the mild stenosis group, moderate stenosis group and the severe stenosis (χ2artery caliber=6.92, Partery caliber=0.08; χ2vein diameter=4.16, Pvein diameter=0.25; χ2arteriolar-venular ratio=1.38,Parteriolar-venular ratio=0.71) . The PSV of central retinal artery in the above groups were (14.6±3.6), (34.4±13.2), (35.7±14.6), (42.3±19.0)cm/s respectively, the data were analyzed by rank-sum test and there was a significant difference (χ2=13.44, P< 0.01) ; The PSV of the posterior ciliary artery in the above groups (17.6±6.5), (15.0±4.6), (13.4±4.3) and (11.0±3.2)cm/s respectively, the data were analyzed by rank-sum test and there was a significant difference (χ2=22.71, P<0.01) , EDV were (5.90±2.2), (5.1±2.1), (4.3±1.5) and (4.3±4.8)cm/s respectively and there was a significant difference (χ2=20.36, P<0.01) .There was a correlation between retinal artery diameter, PSV and EDV of the central retinal artery, PSV and EDV of the posterior ciliary artery and the diameter of the internal carotid artery but without linear correlation. (rartery caliber=-0.23, Partery caliber=0.01; rPSV of central retinal artery= -0.29, PPSV of central retinal artery<0.01; rPSV of posteri or ciliary artery=-0.34, PPSV of posterior ciliary artery<0.01, rEDV of posterior ciliary artery=-0.35, PEDV of posterior ciliary artery<0.01). Conclusions: There was a correlation between retinal artery diameter, PSV and EDV of the central retinal artery, PSV and EDV of the posterior ciliary artery and the diameter of the internal carotid artery. PSV of the central retinal artery, PSV and EDV of the posterior ciliary artery changed significantly when the internal carotid artery stenosis existed. (Chin J Ophthalmol, 2016, 52: 905-910).