COMPARATIVE STUDY OF RETROBULBAR HEMODYNAMICS IN HYPERTENSIVES WITH RETINOPATHY AND HYPERTENSIVES WITHOUT RETINOPATHY IN IBADAN, NIGERIA

Adenigba P.T¹, Adekanmi A.J^1,2*, Ogun O.A^3
1Department of Radiology, University College Hospital Ibadan, Nigeria
²Department of Radiology, College of Medicine, University of Ibadan, Nigeria
³Department of Ophthalmology College of Medicine, University of Ibadan, Nigeria

*Corresponding Author: Dr. Ademola J Adekanmi Email: kanmiademola@gmail.com
Source of grant: None
Conflict of Interest: None

ABSTRACT

Background: Essential hypertension is a multisystemic disorder that may cause retinopathy. Doppler ultrasonography of the retrobulbar arteries is an established imaging modality that detects early vascular changes in hypertensive retinopathy, thus ensuring timely institution of care and prevention of end-organ damage.

Aim and objectives: To compare the retrobulbar arterial flow parameters in hypertensive adults with and without retinopathy with flow parameters in normotensive subjects using Doppler ultrasonography.

Setting: Departments of Radiology and Ophthalmology, University College Hospital, Ibadan, Nigeria.

Methodology: This was a prospective, cross-sectional study among 120 subjects, comprising 60 hypertensives (Group 1; subgroup 1a- subjects without retinopathy (n = 30), and subgroup 1b-subjects with retinopathy, n = 30) and 60 age-sex-matched non-hypertensive subjects (Group 2), conducted at the University College Hospital, Ibadan. Demographic information and clinical data were obtained from the participants and their case files. All participants had fundoscopy, intraocular pressure measurements, and ophthalmic artery (OA), and central retinal artery (CRA) colour Doppler ultrasound. Data were analyzed using SPSS version 23.

Results: The PSV and EDV of the CRA in the healthy controls (10.8±2.54cm/s and 4.56 ± 1.32cm/s) were significantly higher than those of group 1a (9.04±1.93cm/s and 3.29±1.12cm/s: P=0.02 and <0.001) and Group 1b cases (5.55±1.32cm/s and 2.48±0.84cm/s: both P<0.001). Additionally, there was also significant difference in the PSV and EDV between groups 1a and 1b (both P<0.001).

Also, the PI and RI in healthy controls (0.93±0.17 and 0.57 ± 0.007) were significantly lower than those of group 1a (1.12±0.25 and 0.63±0.09: P=0.005 and P<0.001) but showed no significant difference from those of Group 1b (0.92±0.25 and 0.53±0.10;P=0.961 and P=0.106). However, the PI and RI in Group 1a were significantly higher than those in Group 1b (P=0.014 and P=<0.001, respectively).

In the Ophthalmic artery, the PSV in healthy controls (14.5±4.54cm/s) was not significantly different from that of group 1a (15.4±7.0cm/s: P=0.847) and Group 1b cases (12.0±4.71cm/s; P=0.107). However, the value in Group 1a was significantly higher than that in group 1b (P=0.045). Furthermore, the RI in healthy controls (0.63±0.08) was significantly lower than that of group 1a (0.68±0.08; P=0.015), but not different from that in 1b (0.63±0.09; P=0.998); the RI in groups 1a and 1b were not significantly different (P=0.060). No significant differences were observed, between the three groups, in the mean values for EDV (p=0.128) and PI (p=0.402) in the ophthalmic artery.

Significant positive correlations were found between PSV and EDV of CRA and duration of hypertension in group 1b (r = 0.395, P = 0.031; r = 0.445, P = 0.014, respectively) but not in 1a. However, there was no significant correlation between RI and degree of retinopathy in group 1b.

Conclusion: The CRA PSV and EDV were significantly higher in healthy controls than in hypertensives, and hypertensives without retinopathy had higher values than those with retinopathy. The PI and RI in healthy controls and hypertensives with retinopathy were not significantly different but both were lower than the values in hypertensives without retinopathy. In the Ophthalmic Artery there were no significant differences in EDV and PI between the three groups but PSV was significantly higher in hypertensives without retinopathy compared to those with retinopathy. Although there was no significant difference in the RI between the two groups of hypertensives, those without retinopathy had higher values than normal controls. Increased retrobulbar Doppler resistance and reduced flow velocities may be the earliest Doppler changes in hypertension without retinopathy, while reversal of these parameters may indicate longstanding hypertensive retinopathy. The positive correlation between the retrobulbar Doppler flow and the duration of disease in hypertensives with retinopathy may help to ascertain longstanding cases of hypertensive retinopathy.

Key words: Hypertension, retinopathy, central retinal artery, ophthalmic artery, ultrasonography.