Retinal Microvascular Resistance Estimated from Waveform Analysis Is Significantly Higher With a Threshold Value in Central Retinal Vein Occlusion

Abstract

Evaluation of blood flow is useful for understanding the severity of central retinal vein occlusion (CRVO). Actual blood flow may be determined by the resistivity of the retinal vein in CRVO. We have previously evaluated mean blur rate (MBR) to reflect total retinal blood flow velocity in CRVO cases using laser speckle flowgraphy (LSFG). This study evaluated retinal total vascular resistance in CRVO cases using the new index of total capillary resistance (TCR) from LSFG. Methods: We measured the TCR of 68 CRVO patients who visited Nagasaki University Hospital between 2009 and 2016 and 42 age-matched controls without systemic disease. We compared TCRs among control eyes, CRVO fellow eyes, and CRVO affected eyes. A CRVO threshold value was then obtained from the receiver operating characteristic curve. Results: MBR was significantly lower for CRVO affected eyes (20.3 ± 8.2) than for control eyes (37.5 ± 8.4; P < 0.01) and CRVO fellow eyes (36.4 ± 10.0; P < 0.01, Dunn's test). TCR was significantly higher for CRVO affected eyes (1.20 ± 0.55) than for control eyes (0.68 ± 0.2; P < 0.01) and CRVO fellow eyes (0.81 ± 0.28; P < 0.01, Dunn's test). The threshold for the presence of CRVO was 0.93 and area under the curve was 0.84. Conclusions: By measuring TCR in addition to MBR, more detailed information regarding CRVO pathology can be obtained. Translational Relevance: Comparison of values before and after treatment may be useful for evaluating the effects of treatment.

Elevated retinal artery vascular resistance determined by novel visualized technique of laser speckle flowgraphy in branch retinal vein occlusion

“…It suggested that the resistance of the retinal artery of BRVO eyes was increased due to BRVO. These results are consistent with previous studies on increased retinal artery resistance in eyes with CRVO 5 , 10 , 11 , 14 .…”

“…In addition, various analyses have been performed on the waveform parameters of MBR 13 . Matsumoto et al reported that total capillary resistance (TCR), a parameter of LSFG, which is the index of resistivity of the retinal vessels calculated in the same manner as PI, was higher in eyes with CRVO 14 . They suggested that blockage of retinal veins may cause high resistivity in the retinal vessels.…”

Novel superpixel method to visualize fundus blood flow resistivity in healthy adults

“…Table 1 shows the systemic parameters and BOM values for the entire ONH (BOM.A), CHD (BOM.CHD), retinal vessels (TCR 37 ), and the tissue surrounding the vessels in the ONH (BOM.T) in relation to sex and age.…”

“…In clinical studies of CRVO 37 , 48 , measurement of TCR in addition to MBR enabled threshold TCR values to be established for the presence (0.93) and absence (0.68 ± 0.20) of CRVO. We calculated TCR values of 0.56 ± 0.28 for men and 0.59 ± 0.27 for women in participants > 50 years old, suggesting the absence of CRVO in our cohort.…”

“…Regarding the threshold of BOM for vascular occlusion, Matsumoto et al reported that the total capillary resistance (TCR), defined as the BOM in the major vessels (arteries and veins) in the ONH, was higher for CRVO patients than for normal subjects, irrespective of sex and age 37 , while Yanagida et al reported a sex-based difference between resistance values in normal subjects 11 . However, these reports did not elaborate on the association with systemic parameters such as body weight, height, or ocular perfusion pressure (OPP).…”