Prevalence of asymptomatic retinal emboli in an Australian urban community

Factors Associated With Incidental Retinal Emboli in the U.S. Adult Population

PURPOSE

We sought to estimate the prevalence of incidental retinal emboli and identify associated factors using a nationally representative sample of the U.S.

POPULATION

DESIGN

Cross-sectional study.

METHODS

We included adult (age ≥40 years) participants of the 2005-2008 National Health and Nutrition Examination Survey (NHANES). Incidental retinal emboli were identified through retinal fundus photography. Multivariable logistic regression was used to determine the association between the presence of retinal emboli and sociodemographic, lifestyle, and clinical factors (age, sex, race/ethnicity, education, income, smoking, alcohol use, body mass index [BMI], hypertension, diabetes, hypercholesterolemia, and history of cardiovascular disease).

RESULTS

This study included 5,764 adults (53% female). Incidental retinal emboli were identified in 0.7% (39/5764) of individuals. The survey-weighted prevalence of retinal emboli increased with age, from 0.1% in participants 40-49 years of age to 1.4% in participants≥70 years of age. The prevalence did not differ by sex or race/ethnicity. Factors associated with retinal emboli after adjusting for age and sex included underweight BMI (odds ratio [OR] 7.24 [95% confidence interval {CI} 1.06-49.3]), current smoking (OR 6.16 [95% CI 1.49-25.5]), low household income (OR 4.41 [95% CI 1.3-15.0]), and hypertension (OR 2.67 [95% CI 1.31-5.44]).

CONCLUSIONS

In a cohort representative of the U.S. adult population, the prevalence of incidental retinal emboli increased with age but did not differ by sex, race, or ethnicity. Further investigation into the potential association of socioeconomic and nutritional status with retinal emboli may enable opportunities to identify individuals with underlying cardiovascular risk.

Asymptomatic retinal emboli and current practice guidelines: a review

Asymptomatic retinal emboli are found in 1-3% of patients on routine fundus examination. As the use of teleretinal imaging for diabetic patients and ocular photography continues to increase, the number of asymptomatic retinal emboli found will also increase. This article will discuss the different aetiologies of retinal emboli and will present an overview of the recommended referrals for further systemic testing and treatment. It is important to communicate well with the primary care physician when asymptomatic retinal emboli are detected to ensure the appropriate investigations are undertaken.

Novel Association between Opioid Use and Increased Risk of Retinal Vein Occlusion Using the National Institutes of Health All of Us Research Program

Purpose

To assess for risk factors for retinal vein occlusion (RVO) among participants in the National Institutes of Health All of Us database, particularly social risk factors that have not been well studied, including substance use.

Design

Retrospective, case-control study.

Participants

Data were extracted for 380 adult participants with branch retinal vein occlusion (BRVO), 311 adult participants with central retinal vein occlusion (CRVO), and 1520 controls sampled among 311 640 adult participants in the All of Us database.

Methods

Data were extracted regarding demographics, comorbidities, income, housing, insurance, and substance use. Opioid use was defined by relevant diagnosis and prescription codes, with prescription use > 30 days. Controls were sampled at a 4:1 control to case ratio from a pool of individuals aged > 18 years without a diagnosis of RVO and proportionally matched to the demographic distribution of the 2019 U.S. census. Multivariable logistic regression identified medical and social determinants significantly associated with BRVO or CRVO. Statistical significance was defined as P < 0.05.

Main Outcome Measure

Development of BRVO or CRVO based on diagnosis codes.

Results

Among patients with BRVO, the mean (standard deviation) age was 70.1 (10.5) years. The majority (53.7%) were female. Cases were diverse; 23.7% identified as Black, and 18.4% identified as Hispanic or Latino. Medical risk factors including glaucoma (odds ratio [OR], 3.29; 95% confidence interval [CI], 2.22-4.90; P < 0.001), hypertension (OR, 2.15; 95% CI, 1.49-3.11; P < 0.001), and diabetes mellitus (OR, 1.68; 95% CI, 1.18-2.38; P = 0.004) were re-demonstrated to be associated with BRVO. Black race (OR, 2.64; 95% CI, 1.22-6.05; P = 0.017) was found to be associated with increased risk of BRVO. Past marijuana use (OR, 0.68; 95% CI, 0.50-0.92; P = 0.013) was associated with decreased risk of BRVO; however, opioid use (OR, 1.98; 95% CI, 1.41-2.78; P < 0.001) was associated with a significantly increased risk of BRVO. Similar associations were found for CRVO.

Conclusions

Understanding RVO risk factors is important for primary prevention and improvement in visual outcomes. This study capitalizes on the diversity and scale of a novel nationwide database to elucidate a previously uncharacterized association between RVO and opioid use.

The Jidong Eye Cohort Study: objectives, design, and baseline characteristics

Background

To describe the objective, design and baseline characteristics of the Jidong Eye Cohort Study (JECS), a community-based cohort in China based on etiology, imaging and biomarkers. The JECS will clarify the pathogenesis of visual impairment and status of ocular indicators in the occurrence and progression of cardio-cerebrovascular and neurological diseases.

Methods

Between August 2019 and January 2020, the JECS recruited consecutive participants aged 18 years and older from the Jidong communities in China. The demographic and clinical characteristics were collected by trained site personnel via face-to-face interviews. The relevant biological samples were also collected. The participants underwent comprehensive ophthalmic examination, such as retinal photography and optical coherence tomography (OCT) angiography. The following outcomes were measured annually: ocular vascular abnormality, optic nerve degeneration, cardiovascular diseases (CVD) and neurological diseases. The study will be performed until 2024.

Results

Among 3377 participants, the average age was 45.0 ± 12.5 years and 1809 (53.6%) were women. Hypertension occurred in 825 individuals (25.0%), diabetes in 258 (7.7%), hyperglycemia in 474 (14.2%), and a CVD history in 100 (3.0%). The mean best-corrected visual acuity was 0.1 logMAR in the recruited subjects. The average OCT signal index was 8.2 ± 1.2. Additionally, the mean vessel densities for the entire measured area were 46.4% and 50.8% for the superficial and deep vascular complex, respectively. Mean area and perimeter of foveal avascular zone was 0.3 mm² and 2.3 mm.

Conclusions

The JECS is a large community-based prospective cohort in North China. Rich data collected from this study will provide the opportunity to identify risk factors, imaging, and biomarkers of visual impairment (either ocular vascular anomalies or optic nerve degeneration) and to evaluate their associations with CVD and neurological diseases.

Retinal arterial occlusion with multiple retinal emboli and carotid artery occlusion disease. Haemodynamic changes and pathways of embolism

Objective

To introduce a special subgroup, retinal artery occlusion (RAO) with multiple emboli, which is highly associated with ipsilateral carotid artery occlusion disease (CAOD).

Methods and analysis

This is a cohort study. Cases of RAO with multiple retinal emboli were consecutively enrolled. All patients underwent at least one of the carotid/cerebral evaluations: carotid arteriography, orbital/carotid colour Doppler ultrasonography and CT angiography to demonstrate haemodynamic changes and to discuss possible mechanisms and pathways of the emboli.

Results

Among 208 RAO eyes, 12 eyes (5.7%) in 11 patients had multiple emboli were recruited in this study. Eleven eyes (91.6%) had ipsilateral carotid plaques and atherosclerosis with high-grade stenosis; among them, five were total carotid occlusion. Haemodynamic changes were found in nine patients with RAO (81.8%) with carotid stenosis 60% or greater. Most compensatory intracranial circulations were re-established via the circle of Willi with antegrade ophthalmic flows, but the direction of ophthalmic flow reversed in three eyes indicating the recruitment of external collaterals. Two cases underwent carotid stent successfully.

Conclusion

RAOs with multiple emboli are rare but highly associated with severe CAOD with haemodynamic flow changes, warning critical condition in carotid/cerebral circulations. Either direct embolism from the carotid or cardiac lesions or indirect embolism via the collateral pathways is the mechanism of pathogenesis. Immediate action should start to manage these patients to prevent further deterioration.

Arterial Occlusions to the Eye: From Retinal Emboli to Ocular Ischemic Syndrome

: Abstract: A loss or lack of blood supply to the eye can result in acute loss of vision. The site of ischemia may be at the level of the retinal arterioles, the central retinal artery, or further back at the ophthalmic and internal carotid artery. Recognizing the symptoms and signs are important to help prevent permanent ischemic and irreversible blindness. The objective of this review article is to provide the general ophthalmologists with information on how to recognize the symptoms and to best manage these patients. The management is to investigate for the cause of the transient monocular visual loss and to apply secondary prevention to address atherosclerotic risk factors to prevent further ischemic events like a stroke.

Prevalence of Retinal Emboli and Acute Retinal Artery Occlusion in Acute Ischemic Stroke

OBJECTIVE

In population-based studies asymptomatic retinal emboli occur in .32%-2.9% of people. Retinal artery occlusion (RAO) may occur concurrently with cerebral stroke but the frequency is unknown. No study has examined how commonly retinal emboli occur in the acute stroke population. We aimed to assess the prevalence of retinal emboli and RAO at the time of carotid territory ischemic stroke.

METHODS

Patients were enrolled prospectively after onset of symptoms consistent with the diagnosis of carotid territory ischemic stroke. Every participant underwent pharmacologic dilation of both pupils and bedside funduscopic examination. Emboli were classified as cholesterol, calcific, platelet/fibrin, or other and categorized by the side of occurrence. Stroke was classified as atheroembolic, cardioembolic, embolic stroke of undetermined source, lacunar, or other. Acute RAO was diagnosed by direct visualization of ischemic retinal whitening.

RESULTS

Sixty-five patients were enrolled with a mean age of 59.2 years; 23 were female (35.4%). Eleven of 65 subjects (16.9%) had retinal emboli visible on funduscopy; all were cholesterol emboli except a single platelet/fibrin embolus in a patient with atheroembolic source. Six patients (9%) had acute RAO and no RAO was seen in the lacunar or undetermined source subgroups.

CONCLUSIONS

Retinal emboli occurred more than 10 times more frequently in the acute stroke patient than in large population-based studies. RAOs also occurred concurrently with ischemic stroke. Although emboli were seen in patients with atheroembolic and cardioembolic sources, all patients with carotid disease had emboli in the ipsilateral eye. Future studies are required to determine if the presence of retinal emboli or RAO may help elucidate an etiology in patients suffering from embolic stroke of undetermined source.

Indications and Outcome of Carotid Doppler Ultrasound: An Ophthalmic Perspective

Purpose

The purpose of this study was to assess indications and outcome of carotid Doppler ultrasound requested by ophthalmologists from an eye hospital over a period of three years.

METHODS

This retrospective study was designed to analyse data for all patients referred to have carotid Doppler ultrasound from 1999 to 2001. Colour fundus photograph was used to ascertain diagnosis of ocular condition. Detailed case note analysis was done to correlate patient details, indication, results of carotid Doppler, and status of anti-platelet treatment as well as presence of other risk factors.

Results

107 patients were included in the study. 46.7% had normal internal carotid on Doppler while 53.3% patients had stenosis, 22.8% of which were significant. 15 out of 24 patients with retinal artery occlusion had internal carotid artery (ICA) stenosis. 2 out of 6 patients with migraine had significant stenosis. 12 patients had retinal vein occlusion (5 were bilateral), 9 of whom showed ICA stenosis. 14 of 15 patients with retinal emboli had stenosis of ICA. Other diagnoses included anterior ischaemic optic neuropathy, cranial nerve palsy, etc. 42 patients had 1 to 3 risk factors, and 11 patients had more than 3 risk factors. Ophthalmologists started anti-platelet management in 24 patients (42.1%) with some degree of ICA stenosis.

CONCLUSIONS

Approximately 55% of our patients referred for carotid Doppler were positive for ICA stenosis with nearly a fifth of such referrals having more than 70% stenosis, which is considered to be clinically significant. Our results highlight the importance of such referrals for carotid Doppler for various ophthalmic conditions by the ophthalmologists.

Review of the association between retinal microvascular characteristics and eye disease

Computerized retinal imaging technologies enable the static and dynamic measurement of a range of retinal microvascular parameters. Large population-based studies have reported associations between these microvascular indices and various ophthalmic diseases including diabetes, age-related macular degeneration, retinal artery embolism, retinal vein occlusion, glaucoma and non-glaucomatous optic neuropathies. Increasingly, sophisticated imaging and analysis techniques have the potential to provide relevant clinical information regarding disease risk and progression; however, further studies are required to verify associations and strengthen the predictive power of these techniques. We summarize the current state of knowledge regarding retinal microvascular characteristics and eye disease.

Prevalence and Associations of Retinal Emboli With Ethnicity, Stroke, and Renal Disease in a Multiethnic Asian Population: The Singapore Epidemiology of Eye Disease Study

Importance

To our knowledge, population-based data on retinal emboli are limited in Asia. Besides its associations with traditional cardiovascular risk factors and stroke, associations between retinal emboli and renal disease and function remain unclear.

Objective

To examine the prevalence of and risk factors for retinal emboli in a large, contemporary, multiethnic Asian population.

Design, Setting, and Participants

This population-based cross-sectional study was conducted from 2004 to 2011 and included a total of 10 033 Chinese, Malay, and Indian persons aged 40 to 80 years residing in the general communities of Singapore. Analyses were performed from November 2016 to February 2017.

Interventions or Exposures

Retinal emboli were ascertained from retinal photographs obtained from both eyes of all participants according to a standardized protocol. Age-standardized prevalence of retinal emboli was calculated using the 2010 Singapore adult population. Risk factors were assessed from comprehensive systemic and ophthalmic examinations, interviews, and laboratory investigations.

Main Outcomes and Measures

Retinal emboli.

Results

Of the 10 033 participants, 9978 (99.5%) had gradable retinal photographs. Of these, 5057 (50.7%) were female, and 3375 (33.8%) were Indian. We identified 88 individuals (0.9%) with retinal emboli; the overall person-specific, age-standardized prevalence of retinal emboli was 0.75% (95% CI, 0.60-0.95), with the highest prevalence seen in the Indian cohort (0.98%), followed by the Chinese (0.73%) and Malay (0.44%) cohorts (P = .03). In multivariable-adjusted analysis, factors associated with prevalent retinal emboli included older age (per 5-year increase; odds ratio [OR], 1.22; 95% CI, 1.05-1.41), Indian ethnicity (compared with Malay ethnicity; OR, 3.58; 95% CI, 1.95-6.60), hypertension (OR, 1.95; 95% CI, 1.03-3.70), chronic kidney disease (OR, 2.05; 95% CI, 1.15-3.64), creatinine level (per SD increase; OR, 1.13; 95% CI, 1.05-1.21), glomerular filtration rate (per SD increase; OR, 0.67; 95% CI, 0.51-0.86), and history of stroke (OR, 3.45; 95% CI, 1.70-6.99).

Conclusions and Relevance

Based on 88 individuals among 9978 participants of 3 major Asian ethnic populations, retinal emboli were most commonly seen in Indian persons and associated with conventional cardiovascular risk factors, stroke, and chronic kidney disease. Therefore, its presence may signal vascular embolic event and damage not only in the brain but also in the kidneys. If these data are confirmed in longitudinal studies, they would suggest that persons with retinal emboli may require both general cardiovascular and renal assessment.

Asymptomatic carotid artery stenosis and retinal nerve fiber layer thickness. A community-based, observational study

Purpose

To examine whether an abnormally thin retinal nerve fiber layer (RNFL) is associated with cerebrovascular insufficiency.

Design

Community-based study.

Methods

The Asymptomatic Polyvascular Abnormalities in Community Study included Chinese aged 40+ years and without histories of cerebrovascular incidents or coronary heart disease. Using transcranial Doppler and carotid duplex ultrasound examination, we assessed presence and degree of an intracranial arterial stenosis (ICAS) and extracranial carotid arterial stenosis (ECAS) and we measured the RNFL thickness by spectral-domain optical coherence tomography.

Results

The study included 3,376 participants with a mean age of 54.3±10.3 years. Thinner RNFL was significantly correlated with a higher prevalence of ECAS (P = 0.035; standardized regression coefficient beta:-0.04; non-standardized regression coefficient B:-0.99; 95% confidence intervals(CI):-1.90,-0.07), after adjusting for age (P<0.001;beta:-0.25;B:-0.26;95%CI:-0.30,-0.22), gender (P = 0.001;beta:-0.07;B:-1.36;95%CI:-2.14,-0.58) and blood concentration of low-density lipoproteins (P = 0.03;beta:0.04;B:0.52;95%CI:0.05,0.98). In a reverse manner, prevalence of ECAS was associated with a thinner RNFL thickness (P = 0.007; odds ratio (OR):0.99; 95%CI:0.98,0.99) after adjusting for older age (P<0.001;OR:1.06;95%CI:10.05,10.7), higher prevalence of ICAS (P = 0.01;OR:1.34;95%CI:1.07,1.69) and higher prevalence of carotid artery plaques (P<0.001;OR:9.18;95%CI:6.93,12.2), and higher blood concentration of total cholesterol (P = 0.03;OR:1.12;95%CI:1.01,1.23). In univariate analysis, an increasing degree of ECAS was significantly correlated with a thinner RNFL.

Conclusions

Higher prevalence and degree of ECAS were correlated with thinner RNFL and vice versa. Patients with abnormally thin RNFL without ocular disease may undergo carotid artery examination to detect asymptomatic carotid artery stenosis. Examination of the RNFL is useful for the diagnosis of cerebrovascular disease.

Assessing Patients with Asymptomatic Retinal Emboli Detected at Retinal Screening

Introduction

Asymptomatic retinal emboli have been associated with diabetes, the presence of significant carotid artery stenosis (≥70%) and an increased risk of stroke. However, there is no clear guidance on how best to investigate and manage patients found to have asymptomatic retinal emboli. Therefore, this study aimed to assess the incidence of significant carotid artery stenosis in patients found to have asymptomatic retinal emboli at diabetic retinopathy screening, and to examine disease management approaches among these patients.

Methods

Patients with new retinal emboli visible at diabetic retinopathy screening were referred to a medical retinopathy clinic and underwent examinations according to a standardized protocol, including carotid Doppler ultrasound and echocardiography. Case notes of patients referred between January 2013 and April 2014 were reviewed. Results of investigations, medication changes and the number of patients who underwent relevant surgical interventions were noted.

Results

Retinal emboli were present in 44 of 13,643 people screened (0.32%). Full data were available for 39 patients. Twenty-two patients (56%) had relevant medication changes. Nine (23%) patients had significant carotid artery stenosis. One underwent carotid endarterectomy, and eight received maximal medical therapy.

Conclusion

Significant carotid artery stenosis was not uncommon in patients with incident retinal emboli at retinal screening. The referral and investigation protocols identified individuals at risk of cerebrovascular events and led to optimized management. Pathways utilizing Doppler ultrasound and physician referral should be more widely implemented.

Meaningful correlation between asymptomatic retinal arteriole emboli and calcified carotid plaque found on panoramic dental imaging of males with diabetes

OBJECTIVE

There is ongoing controversy with regard to the stability of calcified carotid artery plaques (CCAPs) seen in the bifurcation area on panoramic images (PIs). Therefore, we sought to evaluate the possibility of these plaques shedding emboli by observing their relationship with ipsilateral retinal emboli.

STUDY DESIGN

The study group included 50 neurologically and visually asymptomatic males with diabetes, with PIs that incidentally demonstrated CCAPs (CCAP+) and contemporaneous digital retinal images that had been obtained for evaluation of diabetic retinopathy. The control group consisted of 50 males with diabetes who were matched for age and body mass index and had undergone both imaging studies and whose PIs were devoid of carotid plaques (CCAP-). The presence of retinal emboli was determined by two ophthalmologists blinded to the patients' medical histories, and the prevalence rates for the two groups were calculated.

RESULTS

The presence of asymptomatic retinal arteriolar emboli was found in the eye ipsilateral to the radiographically observed carotid atheroma in 10 of 50 (20%) of the patients in the CCAP+ group, compared with 2 of 50 (4%) in the CCAP- group, and this difference was statistically significant (Fisher's exact P < .03).

CONCLUSIONS

Some male patients with diabetes mellitus type II having calcified carotid artery atheromas in the bifurcation area, as visualized on PIs, may have significant sequelae as evidenced by retinal artery emboli.

Retinal emboli

Retinal emboli are opacities identified in retinal arterioles and are often incidental findings on ophthalmic examination. They are generally composed of cholesterol, platelet-fibrin, or calcium and are thought to arise from carotid arteries, coronary arteries, or cardiac valves. In the general population, the estimated prevalence is 0.2% to 1.3%, and the estimated incidence is 0.9% to 2.9%. The transient nature of retinal emboli likely explains the variations between and within these reported figures. The strongest risk factor for retinal emboli is smoking, which has been reported consistently across many studies. Other likely risk factors include older age, hypertension, male sex, total cholesterol, coronary artery disease, and history of coronary artery bypass grafting. The presence of multiple risk factors, as is common in many patients, confers a higher risk for retinal emboli. Several studies suggest that retinal emboli predict an increase in stroke-related, all-cause, and possibly cardiovascular mortality. Due to these sequelae, patients often undergo further workup, most commonly carotid ultrasonography. However, given the low prevalence of significant carotid disease in patients with retinal emboli, further workup, such as carotid ultrasound, should be reserved for those with risk factors for carotid disease. All patients would benefit from medical optimization and coordinated care with the primary care physician.

The risk of acute coronary syndrome after retinal artery occlusion: a population-based cohort study

AIM

To investigate the risk of acute coronary syndrome (ACS) following retinal artery occlusion (RAO).

METHODS

The study cohort included all patients diagnosed with RAO between January 1999 and December 2008 (n=688) in the Taiwan Longitudinal Health Insurance Database 2000. The control group included randomly selected patients (n=4128) from the same database that were matched to the study group, using a propensity score, for age, gender, and comorbid diabetes mellitus, hypertension, hyperlipidaemia, chronic renal disease and atrial fibrillation status. The ACS-free survival rate was calculated using Kaplan-Meier analysis. Cox proportional hazard regression analysis was used to obtain the adjusted HR for ACS after adjustment for potential confounding factors. The incidence and risk of ACS were compared between the RAO and control groups.

RESULTS

Thirty-seven patients in the RAO group (5.38%) and 138 controls (3.34%) had ACS (p=0.0063) during the follow-up period, resulting in a significantly higher risk of ACS in the RAO group (HR=1.67, 95% CI 1.16 to 2.40). After adjustment for potential confounders, the HR for developing ACS in the RAO group was 1.72 (95% CI 1.20 to 2.47) times higher than that of controls. When stratified by RAO type, the adjusted HR for ACS was 3.57 (95% CI 2.09 to 6.10) for the central RAO subgroup.

CONCLUSIONS

We found that RAO increased the risk for ACS. We recommend thorough follow-up cardiovascular examinations and medical prevention for ACS in patients following RAO.

Nationwide incidence of clinically diagnosed central retinal artery occlusion in Korea, 2008 to 2011

PURPOSE

To define the incidence and demographics of clinically diagnosed central retinal artery occlusion (CRAO) in Korea.

DESIGN

Nationwide population-based retrospective study using data entered into the Korean national health claims database from 2007 to 2011.

PARTICIPANTS

Data of the entire Korean population (N = 47,990,761, based on the 2010 census) were analyzed.

METHODS

We used the national health claims database to identify patients diagnosed with CRAO. Incident cases were those with no claims related to CRAO in 2007 and were included once on the earliest claims related to CRAO in the years 2008 to 2011. Incident cases had a disease-free period before diagnosis of at least 1 to 4 years. The average incidence rate of CRAO was estimated according to the entire Korean population.

MAIN OUTCOME MEASURES

The person-time incidence rates of clinically diagnosed CRAO in Korea, including the age- and sex-specific incidence rates, were estimated.

RESULTS

A total of 3464 CRAO cases (59.1% men) were identified. The incidence rate of clinically diagnosed CRAO during the study period was 1.80 per 100,000 person-years (95% confidence interval [CI], 1.74-1.86). The incidence rate among men and women was 2.15 (95% CI, 2.05-2.24) and 1.47 (95% CI, 1.39-1.54) per 100,000 person-years (male-to-female ratio, 1.47), respectively. The age-specific male-to-female ratios were constant between the ages of 30 and 89 years (range, 1.51-2.10 years). The highest incidence of 10.08 (95% CI, 8.80-11.35) per 100,000 person-years was observed in those aged 80 to 84 years (14.65 [95% CI, 11.90-17.40] and 8.00 [95% CI, 6.63-9.37] per 100,000 person-years for men and women aged 80-84 years, respectively). The incidence rate of CRAO increased exponentially with age until the 9th decade of life.

CONCLUSIONS

To our knowledge, this is the first nationwide epidemiologic study of CRAO in individuals of all ages. The incidence rate of CRAO in Korea increased exponentially with increasing age and was highest among those aged 80 to 84 years. Moreover, the incidence rate in men was 1.47 times higher than that in women.

Asymptomatic polyvascular abnormalities in community (APAC) study in China: objectives, design and baseline characteristics

OBJECTIVE

The population-based "Asymptomatic Polyvascular Abnormalities in Community (APAC) Study was designed to examine prevalence and associations of asymptomatic polyvascular abnormalities (APA) in a general population. In this report, the objectives, design and baseline data of the APAC study are described.

METHODS

The study included 5,440 participants (40.1% women) with an age of 40+ years who were randomly selected from the population of the Kailuan Study which included 101,510 employees and retirees of the Kailuan Co. Ltd, a large coal mine industry located in Tangshan, Hebei, China. Exclusion criteria were previous cerebral stroke, transient ischemic attacks and coronary heart disease. In 2010 and 2011, information on potential cardiovascular risk factors was collected and all participants underwent transcranial Doppler sonography, measurement of the ankle brachial index, and bilateral carotid duplex sonography. In a first follow-up examination in 2012/2013, retinal photography and spectral-domain optical coherence tomography were additionally performed. In a planned long-term follow-up, data from clinical examinations and laboratory tests and the occurrence of cardiovascular or cerebrovascular events will be collected to build up a predicting model for the risk of ischemic events.

RESULTS

At baseline, mean age of the participants was 55.2 ± 11.8 years, and men showed a significantly (P<0.001) higher prevalence of arterial hypertension (55.5% vs. 36.5%) and hyperlipidemia (50.7% vs. 46.0%) and a higher blood homocysteine concentration (18.68 ± 10.28 µmol/L versus 11.69 ± 6.40 µmol/L).

CONCLUSIONS

The APAC is the first study to prospectively evaluate the relationship between intracranial arterial stenosis, retinal nerve fiber layer changes, retinal microvascular signs, and the eventual development of cerebrovascular or cardiovascular events.

Impact of arterial hypertension on the eye

Systemic hypertension has been linked to a wide range of major eye diseases. High arterial blood pressure (BP) decreases choroidal circulatory flow, increases intraocular pressure, and is associated with retinal microvascular abnormalities and prevalence of retinal vein occlusion (RVO) and retinopathy. This review offers a comprehensive overview of ocular diseases associated with hypertension and emphasizes their importance as predictors to future cardiovascular events. It also gives evidence-based clinical data for the therapeutic approach of eye disease in hypertensive patients.

Frequency and risk factors of non-retinopathy ocular conditions in people with diabetes: the Singapore Malay Eye Study

AIM

To investigate the frequency and risk factors of non-retinopathy ocular conditions in persons with diabetes.

METHODS

A population-based cross-sectional study of 3176 Malay persons aged between 40 and 79 years in Singapore was conducted. Cataract, glaucoma, refractive errors, age-related macular degeneration, dry eye, epiretinal membrane, ocular hypertension and retinal conditions were assessed based on standardized interviews, clinical examinations and laboratory investigations.

RESULTS

A total of 768 participants (24.2%) had diabetes. People with diabetes were more likely to have cortical cataract (52.1 vs. 37.3%, P < 0.001), ocular hypertension (10.9 vs. 7.4%, P = 0.002) and epiretinal membrane (17.2 vs. 10.1%, P < 0.001) compared with those without diabetes. The odds of having cortical cataract (odds ratio 1.63, 95% CI 1.20-2.20) and epiretinal membrane (among those with previous cataract surgery: odds ratio 1.63, 95% CI 1.20-2.20) were significantly higher in people with diabetes compared with those without. The population attributable risks for cortical cataract and epiretinal membrane because of diabetes were 8.7 and 9.0%, respectively. In persons with diabetes, hypertension and high cholesterol were the major risk factors associated with non-retinopathy eye complications such as ocular hypertension (odds ratio 1.18, 95% CI 1.04-1.33) and retinal emboli (odds ratio 1.99, 95% CI 1.05-3.80).

CONCLUSION

Our results allow clinicians to better inform patients with diabetes that they are more likely to have cortical cataract and epiretinal membranes (those with previous cataract surgery) in addition to diabetic retinopathy. Two modifiable risk factors-blood pressure and cholesterol associated with ocular hypertension and retinal emboli, respectively-are also risk factors for non-retinopathy ocular conditions in persons with diabetes.

Ophthalmic features of systemic diseases

The eye is intricately integrated with the functions of the body. Ocular changes may precede or run concurrently with various systemic conditions and often represent important prognostic indicators of disease progression. In addition to a thorough diagnostic evaluation and treatment of underlying processes, individuals with systemic diseases and concurrent ocular changes may need comprehensive ophthalmic examination to reduce the risk of visual impairment and morbidity. In this review the authors highlight the clinically relevant ocular signs that occur parallel with systemic conditions. In particular, the study focuses on the varied clinical presentations that can lead to rapid diagnosis to improve management of eye disorders that accompany systemic diseases.

A retrospective review of the management of asymptomatic retinal emboli identified during diabetic retinopathy screening: a case of inappropriate referral?

Background

Diabetic retinopathy screening generates many referrals of diabetic patients to ophthalmic clinics for incidental non-retinopathy pathology such as asymptomatic retinal emboli. Evidence exists that these patients have a 10 fold increased relative risk of stroke. With this in mind we evaluated our current management for this group.

Methods

A retrospective review was conducted for patients referred by the screening programme to the Eye Clinic, Derbyshire Royal Infirmary in 2008. Data were collected on modifiable cardiovascular risk factors, investigations conducted and treatment decisions.

Results

Nineteen patients were identified with asymptomatic retinal emboli: nine (47%) had known vascular disease; 13 patients (68%) were taking anti-platelet agents and 11 (58%) a statin. The mean blood pressure (BP) was 152/81 mmHg, but 10 patients (53%) had a BP > 140 mmHg and 47% were on antihypertensive medication. Carotid Doppler scans were performed on eight patients (42%), of whom two (25%) had stenosis over 70%. No new medications such as aspirin were started, nor any alteration made to anti-hypertensive medication.

Conclusion

As the eye clinic visit resulted in no change to the patients’ management, we feel that it may be more appropriate to refer these patients to a medical clinic to optimise their stroke risk reduction management. Br J Diabetes Vasc Dis 2010; 10:126—129

Risk factors for retinal arteriolar emboli in coronary artery disease

This study determined the prevalence of retinal arteriolar emboli risk factors in 148 patients (86 males) diagnosed with coronary artery disease who required coronary artery bypass graft surgery (mean +/- SD age 59.1 +/- 12.9 years). The prevalence of smoking was 50.7%, hypertension was 49.3%, diabetes mellitus was 27.0% and obesity was 31.1%. Retinal arteriolar emboli were detected using binocular indirect ophthalmoscopy of both eyes. They were found in 10 patients (6.8%) and identified as the cholesterol type. Patients were divided according to their baseline low-density lipoprotein cholesterol (LDL-C) serum level; retinal arteriolar emboli were significantly more frequent in patients with LDL-C levels > 100 mg/dl. These results demonstrate that the prevalence of hypercholesterolaemia and high LDL-C were increased in patients with retinal arteriolar emboli. Identification and treatment of modifiable risk factors, such as high LDL-C and hypercholesterolaemia, might be beneficial in these individuals.

Retinal Microvascular Signs: A Key to Understanding the Underlying Pathophysiology of Different Stroke Subtypes?

Background

The heterogeneity of the pathology of stroke has been a major difficulty in assessing new treatments for acute stroke, and contributes to the complexity of stroke medicine. Some underlying mechanisms are poorly understood, such as small vessel (lacunar) disease. New technology such as advanced brain imaging has transformed our knowledge of large vessel disease and we suggest that other new technology such as detailed analysis of retinal vessels may provide new insights into the pathology of small vessel (lacunar) stroke disease. We hypothesise that retinal microvascular signs differ by pathological stroke subtype, and we plan to test this hypothesis in over 1000 acute stroke patients.

Summary

Eligible patients undergo a standardised neurological assessment followed by digital retinal photography. At a consensus meeting, an anatomical and aetiological classification is determined. Retinal photographs will be assessed qualitatively (e.g. retinal emboli, arteriovenous nicking) and quantitatively (arteriolar/venule ratio). Six-month vascular event rates together with disability and vital status are collected.

Conclusion

Retinal vessel appearances may provide a ‘window’ to the brain and help determine the important underlying pathophysiological mechanisms of small vessel disease stroke.

Prevalence and risk factors of retinal arteriolar emboli: the Singapore Malay Eye Study

PURPOSE

To examine the prevalence and risk factors of retinal arteriolar emboli, a risk predictor of stroke, in an Asian population.

DESIGN

Population-based cross-sectional study.

METHODS

Retinal emboli were ascertained from retinal photographs obtained from both eyes of 3,265 Asian Malays, aged 40 to 80 years, according to a standardized protocol. Risk factors were assessed from detailed standardized interviews, clinical examinations, and laboratory investigations.

RESULTS

The overall prevalence of retinal emboli was 0.6% (95% confidence interval [CI], 0.58 to 0.62). A finding of retinal emboli was strongly associated with increasing age (P = .005, for trend), but age-stratified prevalence rates were still lower than those reported from previous population-based studies of White persons. After adjusting for age and gender, the presence of retinal emboli was associated with cigarette smoking (odds ratio [OR], 5.96; 95% CI, 1.75 to 20.32), elevated total cholesterol (OR, 5.21; 95% CI, 1.93 to 12.82), low-density lipoprotein cholesterol (OR, 2.98; 95% CI, 1.20 to 7.39), and self-reported history of angina (OR, 5.67; 95% CI, 1.62 to 19.91). These associations remained significant in multivariate analysis with additional adjustment for other risk factors.

CONCLUSIONS

Retinal emboli are less common in Asians than in similarly aged White persons, but are associated with similar cardiovascular risk factors.

Prevalence and associations of asymptomatic retinal emboli in Latinos: the Los Angeles Latino Eye Study (LALES)

PURPOSE

To study the prevalence and associations of asymptomatic retinal emboli in a cohort of Latinos and to compare these findings with those of previous population studies.

DESIGN

Population-based cross-sectional study.

METHODS

All participants in this study underwent a comprehensive eye examination, including fundus photography. Photographs were graded by trained masked graders. Lifestyle factors and medical history were obtained during extensive interviews. Blood pressure, serum glucose, and glycosylated hemoglobin were measured. Age- and gender-specific prevalence rates were calculated. Odds ratios (ORs) were calculated using stepwise logistic regression analyses to identify independent risk factor associated with asymptomatic retinal emboli.

RESULTS

Photographs gradable for retinal emboli were obtained from 5,959 participants. For all participants, the prevalence of definite asymptomatic retinal emboli was 0.4% (n = 26). Stepwise logistic regression analyses identified smoking (> five pack years; OR, 4.3) and history of coronary artery disease (OR, 2.8) to be associated independently with retinal emboli (P < .05).

CONCLUSIONS

We found a lower prevalence of asymptomatic retinal emboli compared with previous population-based studies. This could be secondary to the Los Angeles Latino Eye Study (LALES) population being younger, having lower blood pressure, and having fewer smokers than other studies. As in other studies, smoking emerges as the strongest association with retinal emboli.

The eye in hypertension

Hypertension has a range of effects on the eye. Hypertensive retinopathy refers to retinal microvascular signs that develop in response to raised blood pressure. Signs of hypertensive retinopathy are frequently seen in adults 40 years and older, and are predictive of incident stroke, congestive heart failure, and cardiovascular mortality--independently of traditional risk factors. Hypertension is also a major risk factor for the development of other retinal vascular diseases, such as retinal vein and artery occlusion, and ischaemic optic neuropathy. High blood pressure increases the risk of both development of diabetic retinopathy and its progression. Adequate control of blood pressure has been proven in randomised clinical trials to reduce vision loss associated with diabetic retinopathy. Finally, hypertension has been implicated in the pathogenesis of glaucoma and age-related macular degeneration. Recognition of the ocular effects of blood pressure could allow physicians to better manage patients with hypertension, and to monitor its end-organ effects.

Homocysteine and retinal emboli: the Blue Mountains Eye Study

PURPOSE

To examine the association between serum homocysteine and retinal emboli in a general older population.

DESIGN

Cross-sectional population-based study.

METHODS

Homocysteine level was determined from fasting venous blood collection at the second Blue Mountains Eye Study (BMES) (n = 3509, age > or =49 years, 1997 to 2000). Retinal emboli were graded from retinal photographs. Using logistic regression, we analyzed associations between serum homocysteine and retinal emboli adjusting for age, gender, hypertension, body mass index, and lipid levels.

RESULTS

After multivariable adjustment, serum homocysteine was associated with presence of retinal emboli (odds ratio (OR) 1.2; 95% confidence interval (CI), 1.0 to 1.6 per standard deviation [4.8 micromol/l] increase in serum homocysteine).

CONCLUSION

Elevated serum homocysteine is weakly associated with increased odds of retinal emboli in this older population-based study.

Retinal arteriolar emboli: epidemiology and risk of stroke

Retinal arteriolar emboli can be found in approximately 1% of adults more than 40 years of age. The frequency of retinal emboli increases with age and are more common in men than in women. Bilateral retinal emboli are rare, although multiple emboli in a single eye may be seen in up to one third of cases. Retinal emboli are associated with the presence of carotid artery plaque and stenosis, hypertension, cigarette smoking, and, possibly, diabetes. There are few prospective studies regarding the risk of stroke associated with retinal emboli. Available data suggest that retinal emboli in otherwise asymptomatic people are associated with a higher risk of stroke and stroke mortality, independent of conventional risk factors. Therefore, these patients are likely to benefit from a careful cardiovascular evaluation for risk stratification. Whether carotid ultrasound and other vascular imaging studies should be performed routinely for all patients with asymptomatic retinal emboli remains uncertain.

Risk factors and significance of finding asymptomatic retinal emboli

PURPOSE

To assess the prevalence rates for asymptomatic retinal emboli among both younger and older individuals, with single and multiple potential risk factors, in order to alert clinicians to the probability of finding retinal emboli in patients with varying characteristics.

METHODS

In all, 3654 people aged 49-97 attending the Blue Mountains Eye Study had a detailed eye examination which included retinal photographs of the central and peripheral retinal fields. Retinal emboli were identified during masked photographic grading and definite cases were adjudicated.

RESULTS

Retinal emboli were found in 51 subjects (1.4% of the population); these included 1.1% of people aged 49-69 years (middle-aged subjects) and 2.0% of people aged more than 70 years (older subjects). Risk factors identified were male sex, increasing age, hypertension, current smoking, history of any vascular event (angina, myocardial infarct, stroke) or history of vascular surgery. Among middle-aged subjects, current smoking and history of hypertension or a vascular event were significantly associated with emboli (odds ratios (OR) 2.3-3.1), while in older subjects, history of vascular surgery was related (OR 4.7). The highest prevalence of emboli (5.5%) was found in people who reported a history of hypertension and also smoked (OR 6.0). Among hypertensive men who smoked, emboli were present in 7.6%.

CONCLUSIONS

This study indicates that although asymptomatic retinal emboli are relatively infrequent in the general older population, these lesions are surprisingly common in people (particularly men) with multiple risk factors. Ophthalmologists could routinely screen for emboli and consider alerting the patients' general practitioners to review vascular risk factors.