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Huang Y, Cheung CY, Li D, Tham YC, Sheng B, Cheng CY, Wang YX, Wong TY. AI-integrated ocular imaging for predicting cardiovascular disease: advancements and future outlook. Eye (Lond) 2024; 38:464-472. [PMID: 37709926 PMCID: PMC10858189 DOI: 10.1038/s41433-023-02724-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 07/26/2023] [Accepted: 08/25/2023] [Indexed: 09/16/2023] Open
Abstract
Cardiovascular disease (CVD) remains the leading cause of death worldwide. Assessing of CVD risk plays an essential role in identifying individuals at higher risk and enables the implementation of targeted intervention strategies, leading to improved CVD prevalence reduction and patient survival rates. The ocular vasculature, particularly the retinal vasculature, has emerged as a potential means for CVD risk stratification due to its anatomical similarities and physiological characteristics shared with other vital organs, such as the brain and heart. The integration of artificial intelligence (AI) into ocular imaging has the potential to overcome limitations associated with traditional semi-automated image analysis, including inefficiency and manual measurement errors. Furthermore, AI techniques may uncover novel and subtle features that contribute to the identification of ocular biomarkers associated with CVD. This review provides a comprehensive overview of advancements made in AI-based ocular image analysis for predicting CVD, including the prediction of CVD risk factors, the replacement of traditional CVD biomarkers (e.g., CT-scan measured coronary artery calcium score), and the prediction of symptomatic CVD events. The review covers a range of ocular imaging modalities, including colour fundus photography, optical coherence tomography, and optical coherence tomography angiography, and other types of images like external eye images. Additionally, the review addresses the current limitations of AI research in this field and discusses the challenges associated with translating AI algorithms into clinical practice.
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Affiliation(s)
- Yu Huang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Carol Y Cheung
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Dawei Li
- College of Future Technology, Peking University, Beijing, China
| | - Yih Chung Tham
- Centre for Innovation and Precision Eye Health and Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Singapore
| | - Bin Sheng
- Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Ching Yu Cheng
- Centre for Innovation and Precision Eye Health and Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Singapore
| | - Ya Xing Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Tien Yin Wong
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Singapore.
- Tsinghua Medicine, Tsinghua University, Beijing, China.
- School of Clinical Medicine, Beijing Tsinghua Changgung Hospital, Beijing, China.
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Asiedu K, Krishnan AV, Kwai N, Poynten A, Markoulli M. Conjunctival microcirculation in ocular and systemic microvascular disease. Clin Exp Optom 2023; 106:694-702. [PMID: 36641840 DOI: 10.1080/08164622.2022.2151872] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/09/2022] [Accepted: 11/21/2022] [Indexed: 01/16/2023] Open
Abstract
The conjunctival microcirculation is an accessible complex network of micro vessels whose quantitative assessment can reveal microvascular haemodynamic properties. Currently, algorithms for the measurement of conjunctival haemodynamics use either manual or semi-automated systems, which may provide insight into overall conjunctival health, as well as in ocular and systemic disease. These algorithms include functional slit-lamp biomicroscopy, laser doppler flowmetry, optical coherence tomography angiography, orthogonal polarized spectral imaging, computer-assisted intravitral microscopy, diffuse reflectance spectroscopy and corneal confocal microscopy. Furthermore, several studies have demonstrated a relationship between conjunctival microcirculatory haemodynamics and many diseases such as dry eye disease, Alzheimer's disease, diabetes, hypertension, sepsis, coronary microvascular disease, and sickle cell anaemia. This review aims to describe conjunctival microcirculation, its characteristics, and techniques for its measurement, as well as the association between conjunctival microcirculation and microvascular abnormalities in disease states.
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Affiliation(s)
- Kofi Asiedu
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Arun V Krishnan
- School of Clinical Medicine, University of New South Wales, Sydney, Australia
- Department of Neurology, Prince of Wales Hospital, Sydney, Australia
| | - Natalie Kwai
- School of Medical Sciences, University of sydney, Sydney, Australia
| | - Ann Poynten
- Department of Endocrinology, Prince of Wales Hospital, Sydney, Australia
| | - Maria Markoulli
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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3
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Koutsiaris AG, Riri K, Boutlas S, Daniil Z, Tsironi EE. A normative blood velocity model in the exchange microvessels for discriminating health from disease: Healthy controls versus COVID-19 cases. Clin Hemorheol Microcirc 2023:CH231780. [PMID: 37182862 DOI: 10.3233/ch-231780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A usual practice in medicine is to search for "biomarkers" which are measurable quantities of a normal or abnormal biological process. Biomarkers can be biochemical or physical quantities of the body and although commonly used statistically in clinical settings, it is not usual for them to be connected to basic physiological models or equations. In this work, a normative blood velocity model framework for the exchange microvessels was introduced, combining the velocity-diffusion (V-J) equation and statistics, in order to define the normative range (NR) and normative area (NA) diagrams for discriminating normal (normemic) from abnormal (hyperemic or underemic) states, taking into account the microvessel diameter D. This is different from the usual statistical processing since there is a basis on the well-known physiological principle of the flow diffusion equation. The discriminative power of the average axial velocity model was successfully tested using a group of healthy individuals (Control Group) and a group of post COVID-19 patients (COVID-19 Group).
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Affiliation(s)
- Aristotle G Koutsiaris
- Medical Informatics and Biomedical Imaging (MIBI) Laboratory, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis Campus, Larissa, Greece
| | - Konstantina Riri
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Stylianos Boutlas
- Department of Respiratory Medicine, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Zoe Daniil
- Department of Respiratory Medicine, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Evangelia E Tsironi
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
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Mailey JA, Moore JS, Brennan PF, Jing M, Awuah A, McLaughlin JAD, Nesbit MA, Moore TCB, Spence MS. Assessment of hemodynamic indices of conjunctival microvascular function in patients with coronary microvascular dysfunction. Microvasc Res 2023; 147:104480. [PMID: 36690270 DOI: 10.1016/j.mvr.2023.104480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/07/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Coronary microvascular dysfunction (CMD) is a cause of ischaemia with non-obstructive coronary arteries (INOCA). It is notoriously underdiagnosed due to the need for invasive microvascular function testing. We hypothesized that systemic microvascular dysfunction could be demonstrated non-invasively in the microcirculation of the bulbar conjunctiva in patients with CMD. METHODS Patients undergoing coronary angiography for the investigation of chest pain or dyspnoea, with physiologically insignificant epicardial disease (fractional flow reserve ≥0.80) were recruited. All patients underwent invasive coronary microvascular function testing. We compared a cohort of patients with evidence of CMD (IMR ≥25 or CFR <2.0); to a group of controls (IMR <25 and CFR ≥2.0). Conjunctival imaging was performed using a previously validated combination of a smartphone and slit-lamp biomicroscope. This technique allows measurement of vessel diameter and other indices of microvascular function by tracking erythrocyte motion. RESULTS A total of 111 patients were included (43 CMD and 68 controls). There were no differences in baseline demographics, co-morbidities or epicardial coronary disease severity. The mean number of vessel segments analysed per patient was 21.0 ± 12.8 (3.2 ± 3.5 arterioles and 14.8 ± 10.8 venules). In the CMD cohort, significant reductions were observed in axial/cross-sectional velocity, blood flow, wall shear rate and stress. CONCLUSION The changes in microvascular function linked to CMD can be observed non-invasively in the bulbar conjunctiva. Conjunctival vascular imaging may have utility as a non-invasive tool to both diagnose CMD and augment conventional cardiovascular risk assessment.
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Affiliation(s)
- Jonathan A Mailey
- Department of Cardiology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, United Kingdom; Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom.
| | - Julie S Moore
- Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom; Integrated Diagnostic Laboratory, Northland House, Ulster University, Belfast, United Kingdom
| | - Paul F Brennan
- Department of Cardiology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, United Kingdom
| | - Min Jing
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown, United Kingdom
| | - Agnes Awuah
- Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom; Integrated Diagnostic Laboratory, Northland House, Ulster University, Belfast, United Kingdom
| | - James A D McLaughlin
- Integrated Diagnostic Laboratory, Northland House, Ulster University, Belfast, United Kingdom; Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown, United Kingdom
| | - M Andrew Nesbit
- Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom; Integrated Diagnostic Laboratory, Northland House, Ulster University, Belfast, United Kingdom
| | - Tara C B Moore
- Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom; Integrated Diagnostic Laboratory, Northland House, Ulster University, Belfast, United Kingdom
| | - Mark S Spence
- Department of Cardiology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, United Kingdom; Integrated Diagnostic Laboratory, Northland House, Ulster University, Belfast, United Kingdom
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Koutsiaris AG, Riri K, Boutlas S, Panagiotou TN, Kotoula M, Daniil Z, Tsironi EE. COVID-19 hemodynamic and thrombotic effect on the eye microcirculation after hospitalization: A quantitative case-control study. Clin Hemorheol Microcirc 2022; 82:379-390. [PMID: 35912735 DOI: 10.3233/ch-221554] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND & OBJECTIVE To quantify the hemodynamic and thrombotic effect of COVID-19 on the eye microcirculation of patients with thromboprophylaxis, shortly after hospital discharge. METHODS This case-control study included 17 COVID-19 survivors (named "COVID-19 Group") and 17 healthy volunteers (named "Control Group"). Axial blood velocity (Vax) and percentage of occluded vessels (POV) were quantified by Conjunctival Video Capillaroscopy (CVC). Microvessels were identified and classified as "capillaries" (CAP), "postcapillary venules of size 1" (PC1), and "postcapillary venules of size 2" (PC2). RESULTS The COVID-19 Group did not differ significantly in basic demographics from the Control Group. In the COVID-19 Group, there was a statistically significant (p < 0.001) reduction of Vax (39%, 49% and 47%, for CAP, PC1, and PC2, respectively) in comparison to the Control Group and a sizeable (p < 0.001) increase of POV (600%) in comparison to the Control Group. CONCLUSIONS COVID-19 not only reduces significantly axial blood velocity in the capillaries and postcapillary venules of the eye but has also a devastating effect on microthrombosis (POV) despite thromboprophylaxis treatment. This gives a possible explanation for long COVID and a hint about the existence of a possibly unknown coagulation factor.
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Affiliation(s)
- Aristotle G Koutsiaris
- Medical Informatics Laboratory, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece
| | - Konstantina Riri
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Stylianos Boutlas
- Department of Respiratory Medicine, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Thomas N Panagiotou
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Maria Kotoula
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Zoe Daniil
- Department of Respiratory Medicine, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Evangelia E Tsironi
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
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Yun Z, Xu Q, Wang G, Jin S, Lin G, Feng Q, Yuan J. EVA: Fully automatic hemodynamics assessment system for the bulbar conjunctival microvascular network. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 216:106631. [PMID: 35123347 DOI: 10.1016/j.cmpb.2022.106631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE Conjunctival microcirculation has been used to quantitatively assess microvascular changes due to systemic disorders. The space between red blood cell clusters in conjunctival microvessels is essential for assessing hemodynamics. However, it causes discontinuities in vessel image segmentation and increases the difficulty of automatically measuring blood velocity. In this study, we developed an EVA system based on deep learning to maintain vessel segmentation continuity and automatically measure blood velocity. METHODS The EVA system sequentially performs image registration, vessel segmentation, diameter measurement, and blood velocity measurement on conjunctival images. A U-Net model optimized with a connectivity-preserving loss function was used to solve the problem of discontinuities in vessel segmentation. Then, an automatic measurement algorithm based on line segment detection was proposed to obtain accurate blood velocity. Finally, the EVA system assessed hemodynamic parameters based on the measured blood velocity in each vessel segment. RESULTS The EVA system was validated for 23 videos of conjunctival microcirculation captured using functional slit-lamp microscopy. The U-Net model produced the longest average vessel segment length, 158.03 ± 181.87 µm, followed by the adaptive threshold method and Frangi filtering, which produced lengths of 120.05 ± 151.47 µm and 99.94 ± 138.12 µm, respectively. The proposed method and one based on cross-correlation were validated to measure blood velocity for a dataset consisting of 30 vessel segments. Bland-Altman analysis showed that compared with the cross-correlation method (bias: 0.36, SD: 0.32), the results of the proposed method were more consistent with a manual measurement-based gold standard (bias: -0.04, SD: 0.14). CONCLUSIONS The proposed EVA system provides an automatic and reliable solution for quantitative assessment of hemodynamics in conjunctival microvascular images, and potentially can be applied to hypoglossal microcirculation images.
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Affiliation(s)
- Zhaoqiang Yun
- School of Biomedical Engineering and Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China; Guangdong Province Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, China
| | - Qing Xu
- School of Biomedical Engineering and Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China
| | - Gengyuan Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Shuang Jin
- School of Biomedical Engineering and Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China
| | - Guoye Lin
- School of Biomedical Engineering and Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China; Guangdong Province Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, China
| | - Qianjin Feng
- School of Biomedical Engineering and Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China; Guangdong Province Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, China.
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
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7
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A meta-analysis of variability in conjunctival microvascular hemorheology metrics. Microvasc Res 2022; 142:104340. [DOI: 10.1016/j.mvr.2022.104340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 12/28/2022]
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Jo HC, Jeong H, Lee J, Na KS, Kim DY. Quantification of Blood Flow Velocity in the Human Conjunctival Microvessels Using Deep Learning-Based Stabilization Algorithm. SENSORS 2021; 21:s21093224. [PMID: 34066590 PMCID: PMC8124391 DOI: 10.3390/s21093224] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/30/2021] [Accepted: 05/01/2021] [Indexed: 11/27/2022]
Abstract
The quantification of blood flow velocity in the human conjunctiva is clinically essential for assessing microvascular hemodynamics. Since the conjunctival microvessel is imaged in several seconds, eye motion during image acquisition causes motion artifacts limiting the accuracy of image segmentation performance and measurement of the blood flow velocity. In this paper, we introduce a novel customized optical imaging system for human conjunctiva with deep learning-based segmentation and motion correction. The image segmentation process is performed by the Attention-UNet structure to achieve high-performance segmentation results in conjunctiva images with motion blur. Motion correction processes with two steps—registration and template matching—are used to correct for large displacements and fine movements. The image displacement values decrease to 4–7 μm during registration (first step) and less than 1 μm during template matching (second step). With the corrected images, the blood flow velocity is calculated for selected vessels considering temporal signal variances and vessel lengths. These methods for resolving motion artifacts contribute insights into studies quantifying the hemodynamics of the conjunctiva, as well as other tissues.
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Affiliation(s)
- Hang-Chan Jo
- Department of Electrical and Computer Engineering, Inha University, Incheon 22212, Korea; (H.-C.J.); (H.J.); (J.L.)
- Center for Sensor Systems, Inha University, Incheon 22212, Korea
| | - Hyeonwoo Jeong
- Department of Electrical and Computer Engineering, Inha University, Incheon 22212, Korea; (H.-C.J.); (H.J.); (J.L.)
| | - Junhyuk Lee
- Department of Electrical and Computer Engineering, Inha University, Incheon 22212, Korea; (H.-C.J.); (H.J.); (J.L.)
| | - Kyung-Sun Na
- Department of Ophthalmology & Visual Science, Yeouido St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul 07345, Korea
- Correspondence: (K.-S.N.); (D.-Y.K.); Tel.: +82-02-3779-1520 (K.-S.N.); +82-32-860-7394 (D.-Y.K.)
| | - Dae-Yu Kim
- Department of Electrical and Computer Engineering, Inha University, Incheon 22212, Korea; (H.-C.J.); (H.J.); (J.L.)
- Center for Sensor Systems, Inha University, Incheon 22212, Korea
- Inha Research Institute for Aerospace Medicine, Inha University, Incheon 22212, Korea
- Correspondence: (K.-S.N.); (D.-Y.K.); Tel.: +82-02-3779-1520 (K.-S.N.); +82-32-860-7394 (D.-Y.K.)
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Brennan PF, McNeil AJ, Jing M, Awuah A, Moore JS, Mailey J, Finlay DD, Blighe K, McLaughlin JAD, Nesbit MA, Trucco E, Moore TCB, Spence MS. Assessment of the conjunctival microcirculation for patients presenting with acute myocardial infarction compared to healthy controls. Sci Rep 2021; 11:7660. [PMID: 33828174 PMCID: PMC8027463 DOI: 10.1038/s41598-021-87315-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 03/23/2021] [Indexed: 11/25/2022] Open
Abstract
Microcirculatory dysfunction occurs early in cardiovascular disease (CVD) development. Acute myocardial infarction (MI) is a late consequence of CVD. The conjunctival microcirculation is readily-accessible for quantitative assessment and has not previously been studied in MI patients. We compared the conjunctival microcirculation of acute MI patients and age/sex-matched healthy controls to determine if there were differences in microcirculatory parameters. We acquired images using an iPhone 6s and slit-lamp biomicroscope. Parameters measured included diameter, axial velocity, wall shear rate and blood volume flow. Results are for all vessels as they were not sub-classified into arterioles or venules. The conjunctival microcirculation was assessed in 56 controls and 59 inpatients with a presenting diagnosis of MI. Mean vessel diameter for the controls was 21.41 ± 7.57 μm compared to 22.32 ± 7.66 μm for the MI patients (p < 0.001). Axial velocity for the controls was 0.53 ± 0.15 mm/s compared to 0.49 ± 0.17 mm/s for the MI patients (p < 0.001). Wall shear rate was higher for controls than MI patients (162 ± 93 s-1 vs 145 ± 88 s-1, p < 0.001). Blood volume flow did not differ significantly for the controls and MI patients (153 ± 124 pl/s vs 154 ± 125 pl/s, p = 0.84). This pilot iPhone and slit-lamp assessment of the conjunctival microcirculation found lower axial velocity and wall shear rate in patients with acute MI. Further study is required to correlate these findings further and assess long-term outcomes in this patient group with a severe CVD phenotype.
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Affiliation(s)
- Paul F Brennan
- Department of Cardiology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, UK.
- Biomedical Sciences Research Institute, Ulster University, Coleraine, UK.
| | - Andrew J McNeil
- Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Min Jing
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown, UK
| | - Agnes Awuah
- Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Julie S Moore
- Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Jonathan Mailey
- Department of Cardiology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, UK
| | - Dewar D Finlay
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown, UK
| | - Kevin Blighe
- Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - James A D McLaughlin
- Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown, UK
| | - M Andrew Nesbit
- Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Emanuele Trucco
- VAMPIRE project, Computing (SSEN), University of Dundee, Dundee, UK
| | - Tara C B Moore
- Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Mark S Spence
- Department of Cardiology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, UK
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10
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Conjunctival Vessels in Diabetes Using Functional Slit Lamp Biomicroscopy. Cornea 2020; 40:950-957. [PMID: 33332897 DOI: 10.1097/ico.0000000000002623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/12/2020] [Indexed: 01/22/2023]
Abstract
PURPOSE This study used functional slit lamp biomicroscopy (FSLB) to quantify conjunctival microvessel parameters in individuals with and without diabetes and examined whether these metrics could be used as surrogate markers of diabetes-related complications. METHODS A cross-sectional study of 98 controls (C), 13 individuals with diabetes without complications (D-C), and 21 with diabetes and related complications (D+C), which included retinopathy, nephropathy, neuropathy, and cardiovascular-, peripheral vascular-, and cerebrovascular diseases, was performed. Bulbar conjunctival metrics (venule diameter, length, axial velocity [Va], cross-sectional velocity [Vs], flow [Q], and branching complexity) were measured using FSLB (digital camera mounted on traditional slit lamp). RESULTS The mean age was 60 ± 11 years, and demographics were similar across the groups. Va and Vs significantly differed between groups. Va was 0.51 ± 0.17 mm/s, 0.62 ± 0.17 mm/s, and 0.45 ± 0.17 mm/s in the C, D-C, and D+C groups, respectively (P = 0.025). Similarly, Vs was 0.35 ± 01.12, 0.43 ± 0.13, and 0.32 ± 0.13 mm/s in the C, D-C, and D+C groups, respectively (P = 0.031). Black individuals had increased Va, Vs, and Q compared with White individuals (P < 0.05), but differences in velocities persisted after accounting for race. Among patients with diabetes, Va and Vs correlated with number of organ systems affected (Va: ρ = -0.42, P = 0.016; Vs: ρ = -0.41, P = 0.021). Va, Vs, and Q significantly (P ≤ 0.005) discriminated between diabetic patients with and without complications (area under the receiver operating curve for Va = 0.81, Vs = 0.79, Q = 0.81). CONCLUSIONS Bulbar conjunctival blood flow metrics measured by FSLB differed between controls, diabetic patients without complications, and diabetic patients with complications. FSLB is a quick, easily accessible, and noninvasive alternative that might estimate the burden of vascular complications in diabetes.
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11
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Liu Z, Jiang H, Townsend JH, Wang J. Improved conjunctival microcirculation in diabetic retinopathy patients with MTHFR polymorphisms after Ocufolin™ Administration. Microvasc Res 2020; 132:104066. [PMID: 32860770 DOI: 10.1016/j.mvr.2020.104066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/25/2020] [Accepted: 08/25/2020] [Indexed: 12/19/2022]
Abstract
PURPOSE To investigate conjunctival microvascular responses in patients with mild diabetic retinopathy (MDR) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms (D + PM) after administration of Ocufolin™, a medical food containing 900 μg l-methylfolate (levomefolate calcium or [6S]-5-methyltetrahydrofolic acid, calcium salt), methylcobalamin, and other ingredients. METHODS Eight D + PM patients received Ocufolin™ for six months (6 M). Bulbar conjunctival microvasculature and microcirculation metrics, including vessel diameter (D), axial blood flow velocity (Va), cross-sectional blood flow velocity (Vs), flow rate (Q), and vessel density (VD, Dbox), were measured at baseline, 4 M, and 6 M. RESULTS The mean age was 54 ± 7 years. No significant demographic differences were found. Conjunctival microcirculation, measured as Va, Vs, and Q was significantly increased at 4 M and 6 M, compared to baseline. Va was 0.44 ± 0.10 mm/s, 0.58 ± 0.13 mm/s, 0.59 ± 0.13 mm/s in baseline, 4 M, and 6 M, respectively (P < 0.01). Similarly, Vs was 0.31 ± 0.07 mm/s, 0.40 ± 0.09 mm/s, 0.41 ± 0.09 mm/s in baseline, 4 M, and 6 M, respectively (P < 0.05). Q was 107.8 ± 49.4 pl/s, 178.0 ± 125.8 pl/s, 163.3 ± 85.8 mm/s in baseline, 4 M, and 6 M, respectively (P < 0.05). The VD at 6 M was significantly higher than that at baseline (P = 0.017). Changes of D were positively correlated with changes of Va, Q, and VD. Effects of MTHFR and haptoglobin polymorphisms on the improvements of conjunctival microcirculation and microvasculature were found. CONCLUSIONS Ocufolin™ supplementation improves conjunctival microcirculation in patients with diabetic retinopathy and common folate polymorphisms.
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Affiliation(s)
- Zhiping Liu
- Ophthalmic Center, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China; Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, USA
| | - Hong Jiang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, USA; Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Justin H Townsend
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, USA
| | - Jianhua Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, USA.
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Blood flow velocity comparison in the eye capillaries and postcapillary venules between normal pregnant and non-pregnant women. Microvasc Res 2020; 127:103926. [DOI: 10.1016/j.mvr.2019.103926] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/27/2019] [Accepted: 09/11/2019] [Indexed: 02/07/2023]
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Quantitative assessment of the conjunctival microcirculation using a smartphone and slit-lamp biomicroscope. Microvasc Res 2019; 126:103907. [PMID: 31330150 DOI: 10.1016/j.mvr.2019.103907] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/19/2019] [Accepted: 07/18/2019] [Indexed: 12/30/2022]
Abstract
PURPOSE The conjunctival microcirculation is a readily-accessible vascular bed for quantitative haemodynamic assessment and has been studied previously using a digital charge-coupled device (CCD). Smartphone video imaging of the conjunctiva, and haemodynamic parameter quantification, represents a novel approach. We report the feasibility of smartphone video acquisition and subsequent haemodynamic measure quantification via semi-automated means. METHODS Using an Apple iPhone 6 s and a Topcon SL-D4 slit-lamp biomicroscope, we obtained videos of the conjunctival microcirculation in 4 fields of view per patient, for 17 low cardiovascular risk patients. After image registration and processing, we quantified the diameter, mean axial velocity, mean blood volume flow, and wall shear rate for each vessel studied. Vessels were grouped into quartiles based on their diameter i.e. group 1 (<11 μm), 2 (11-16 μm), 3 (16-22 μm) and 4 (>22 μm). RESULTS From the 17 healthy controls (mean QRISK3 6.6%), we obtained quantifiable haemodynamics from 626 vessel segments. The mean diameter of microvessels, across all sites, was 21.1μm (range 5.8-58 μm). Mean axial velocity was 0.50mm/s (range 0.11-1mm/s) and there was a modestly positive correlation (r 0.322) seen with increasing diameter, best appreciated when comparing group 4 to the remaining groups (p < .0001). Blood volume flow (mean 145.61pl/s, range 7.05-1178.81pl/s) was strongly correlated with increasing diameter (r 0.943, p < .0001) and wall shear rate (mean 157.31 s-1, range 37.37-841.66 s-1) negatively correlated with increasing diameter (r - 0.703, p < .0001). CONCLUSIONS We, for the first time, report the successful assessment and quantification of the conjunctival microcirculatory haemodynamics using a smartphone-based system.
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