Relationship between Brachial–Ankle Pulse Wave Velocity and Fundus Arteriolar Area Calculated Using a Deep-Learning Algorithm

Abstract

Purpose

Retinal vessels reflect alterations related to hypertension and arteriosclerosis in the physical status. Previously, we had reported a deep-learning algorithm for automatically detecting retinal vessels and measuring the total retinal vascular area in fundus photographs (VAFP). Herein, we investigated the relationship between VAFP and brachial–ankle pulse wave velocity (baPWV), which is the gold standard for arterial stiffness assessment in clinical practice.

Methods

Retinal photographs (n = 696) obtained from 372 individuals who visited the Keijinkai Maruyama Clinic for regular health checkups were used to analyze VAFP. Additionally, the baPWV was measured for each patient. Automatic retinal-vessel segmentation was performed using our deep-learning algorithm, and the total arteriolar area (AA) and total venular area (VA) were measured. Correlations between baPWV and several parameters, including AA and VA, were assessed.

Results

The baPWV was negatively correlated with AA (R = –0.40, n = 696, P < 2.2e-16) and VA (R = –0.36, n = 696, P < 2.2e-16). Independent variables (AA, sex, age, and systolic blood pressure) selected using the stepwise method showed a significant correlation with baPWV. The estimated baPWV, calculated using a regression equation with variables including AA, showed a better correlation with the measured baPWV (R = 0.70, n = 696, P < 2.2e-16) than the estimated value without AA (R = 0.68, n = 696, P < 2.2e-16).

Conclusions

AA and VA were significantly correlated with baPWV. Moreover, baPWV estimated using AA correlated well with the actual baPWV. VAFP may serve as an alternative biomarker for evaluating systemic arterial stiffness.

Keywords:

• Arteriosclerosis
• imaging
• retinal arteriolar narrowing
• deep learning system
• pulse wave velocity

Disclosure statement

Kanae Fukutsu, Michiyuki Saito, Kousuke Noda, and Susumu Ishida have a patent with NIDEK Co., Ltd. Gamagori, Japan. Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University received a grant from NIDEK Co., Ltd. to establish the endowed course named as “Department of Ocular Circulation and Metabolism.” Ryosuke Shiba and Naoki Isogai are employees of NIDEK Co., Ltd.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, KF, and MS. The data are not publicly available due to their containing information that could compromise the privacy of research participants.

Additional information

Funding

This work was supported by NIDEK Co., Ltd. (Gamagori, Japan).