Six billion people in low- and middle-income countries (LMICs) lack timely or ready access to safe and affordable cardiac surgical care when needed, which remains a low priority on the global public ...health and global surgery agenda. Here, we report the results of a state-of-the-art review of cardiac surgical care in LMICs to highlight the important milestones and current progress as well as the challenges associated with the expansion of sustainable global cardiac surgery for those in need.
A literature review was performed searching the PubMed/MEDLINE and Google Scholar databases using a combination of cardiac surgery, global health, and LMIC keywords. The Institute for Health Metrics and Evaluation Global Burden of Disease Results Tool was used to assess the global burden of disease related to cardiovascular surgical diseases.
High-income countries are estimated to have more than 100 times as many cardiac surgeons per million population compared with low-income countries. There are more than 4000 cardiac centers worldwide, but less than 1 center per 10 million population in LMICs. Approximately 1.5 million cardiac operations are performed globally, of which a disproportionally low number are in LMICs. Despite the high costs associated with cardiac operations, recent data suggest the favorable cost-effectiveness thereof in LMICs. Opportunities arise to sustainably integrate cardiac surgery in holistic health systems strengthening interventions.
Skepticism underlying the need, feasibility, and cost-effectiveness of cardiac surgery in LMICs prevails, but recent advances, successful case studies, and existing data illustrate the potential of expanding cardiac care globally.
Basal laminar deposit (BLamD) is a consistent finding in age-related macular degeneration (AMD). We quantified BLamD thickness, appearance, and topography in eyes of aged donors with and without AMD ...and evaluated its relationship to other components of the retinal pigment epithelium-basal lamina/Bruch's membrane (RPE-BL-BrM) complex.
Donor eyes (n = 132) were classified as normal (n = 54), early to intermediate AMD (n = 24), geographic atrophy (GA; n = 13), and neovascular AMD (NV; n = 41). In high-resolution histology, we assessed RPE, BLamD, and BrM thicknesses and phenotypes at 3309 predefined locations in the central (foveal and perifovea) and superior (perifoveal) sections. Pre-mortem optical coherence tomography (OCT) imaging of a 90-year-old woman was compared to postmortem histopathology.
In non-atrophic areas of AMD eyes, the RPE-BLamD is thick (normal = 13.7 µm, early-intermediate = 16.8 µm, GA = 17.4 µm, NV = 18.7 µm), because the BLamD is thick (normal = 0.3 µm, early-intermediate = 5.5 µm, GA = 4.1 µm, NV = 5.3 µm). RPE layer thickness is similar across these stages. Disease-associated variants of BLamD (thick, late, basal mounds) cluster subfoveally. A thick BLamD is visible on OCT as a hyporeflective split in the RPE-BL-BrM complex. BrM is thin (3.5 µm) in NV (normal = 4.2 µm, early to intermediate = 4.4 µm, and GA = 4.2 µm).
The RPE-BL-BrM complex is thick in AMD, driven by the accumulation and expansion of BLamD rather than expansion of either three-layer BrM, RPE-BL, or RPE. BLamD is clinically appreciable by OCT in some patients as a non-neovascular "split RPE-BL-BrM complex" or "double-layer sign." BLamD may contribute toward the formation and progression of high-risk drusen yet also exhibit protective properties.
Lipofuscin and melanolipofuscin organelles in retinal pigment epithelium (RPE) cells are signal sources for clinical fundus autofluorescence (AF). To elucidate the subcellular basis of AF imaging, we ...identified, characterized, and quantified the frequency of RPE morphology and AF phenotypes in donor eyes with age-related macular degeneration (AMD).
In 25 RPE-Bruch's membrane flat mounts from 25 eyes, we analyzed 0.4-μm z-stack epifluorescence images of RPE stained with phalloidin for actin cytoskeleton. Using a custom ImageJ plugin, we classified cells selected in a systematic unbiased fashion in six phenotypes representing increasing degrees of pathology. For each cell, area, AF intensity, and number of Voronoi neighbors were compared with phenotype 1 (uniform AF, polygonal morphology) via generalized estimating equations. We also analyzed each cell's neighborhood.
In 29,323 cells, compared with phenotype 1, all other phenotypes, in order of increasing pathology, had significantly larger area, reduced AF, and more variable number of neighbors. Neighborhood area and AF showed similar, but subtler, trends. Cells with highly autofluorescent granule aggregates are no more autofluorescent than others and are in fact lower overall in AF. Pre-aggregates were found in phenotype 1. Phenotype 2, which exhibited degranulation despite normal cytoskeleton, was the most numerous nonhealthy phenotype (16.23%).
Despite aggregation of granules that created hyperAF aggregates within cells, overall AF on a per cell basis decreased with increasing severity of dysmorphia (abnormal shape). Data motivate further development of subcellular resolution in clinical fundus AF imaging and inform an ongoing reexamination of the role of lipofuscin in AMD.
Type 1 macular neovascularization (MNV) secondary to age-related macular degeneration (AMD) may sustain hypoxic and micronutrient-insufficient outer retinal cells compensatorily. We explored this ...hypothesis via histologic analysis of an eye with a shallow irregular retinal pigment epithelial elevation (SIRE) on OCT and good vision.
Case study and clinicopathologic correlation.
A white woman with untreated nonexudative neovascular AMD and 20/30 visual acuity (left eye) and neovascular AMD (right eye), with 9 years' multimodal imaging before dying at 90 years of age.
The left eye was preserved 6.25 hours after death and prepared for submicrometer epoxy resin sections and transmission electron microscopy aligned to clinical OCT B-scans. Inside and outside the MNV area, layer thicknesses, phenotypes, and vascular density of native choriocapillaris and neovessels were measured. Lengths of choriocapillaries and intervening gaps in the index eye and in early AMD eyes and healthy eyes with similar age (n = 19 each) from the Project MACULA (Maculopathy Unveiled by Laminar Analysis) online histopathologic resource (http://projectmacula.cis.uab.edu/) were measured with custom software (Caps and Gaps).
Descriptive features, vascular density, histologic and OCT layer thicknesses, and distribution of choriocapillaries and intervening gaps.
The SIRE correlated to a type 1 MNV that expanded slowly without evidence of exudation and with numerous choroidal vessels traversing Bruch's membrane defects, some visible on OCT. Tissue layers in and adjacent to the MNV area showed continuous RPE and characteristic AMD deposits. Capillary-like neovessels with fenestrations and caveolae resembling native choriocapillaris lined the retinal pigment epithelium (RPE) with a vascular density comparable with surrounding non-MNV areas. Relative to early AMD and healthy aged eyes, the index eye showed similar capillary lengths but larger gaps between vessels, indicating dropout. Outer nuclear layer thickness was preserved and showed less photoreceptor degeneration over areas of relative choriocapillaris health, including the type 1 MNV.
Eyes with nonexudative type 1 MNV in AMD may progress to exudation, yet this stable MNV complex supported outer retinal structure for 9 years. Distinguishing features were numerous connecting vessels, high density of neovessels, continuous RPE, and slow growth. Maintaining beneficial type 1 MNV may be a therapeutic strategy.
Government motor vehicle crash reports used in the study of driver safety can be biased and incomplete. Naturalistic driving methods using in-vehicle instrumentation have been developed in recent ...years to objectively measure crashes and near crashes as they occur on the road using video and vehicle kinematic data.
To examine visual risk factors associated with at-fault crashes and near crashes among older drivers, most of whom have age-related eye conditions associated with vision impairment.
This prospective cohort study was conducted at an academic ophthalmology clinic from January 1, 2015, to November 10, 2018, among 154 adults 70 years of age or older who were legally licensed in Alabama and who reported currently driving at least 4 days per week; 137 of 151 participants (90.7%) had an age-related eye condition in at least 1 eye. Drivers participated in a baseline visual function assessment followed by installation of a data acquisition system recording multichannel synchronized video and vehicle kinematics in their personal vehicle. Drivers were instructed to drive for 6 months as they normally would during everyday life. Statistical analysis was performed from June 15 to September 15, 2020.
The rate of combined incident at-fault crashes and near crashes, defined by the number of events and the number of miles driven.
The sample consisted of 154 drivers (85 men 55.2%; mean SD age, 79.3 5.1 years). Visual functions associated with crash and near-crash involvement included impaired contrast sensitivity (rate ratio RR, 2.7; 95% CI, 1.3-5.5), moderate (RR, 2.3; 95% CI, 1.1-4.9) and severe (RR, 5.0; 95% CI, 2.2-11.7) slowing in visual processing speed, and elevated motion perception thresholds for a drifting grating (RR, 1.9; 95% CI, 1.1-3.5). Those with impaired peripheral visual field sensitivity had increased rates of crashes and near crashes (RR, 1.8; 95% CI, 1.0-3.3); however, this finding was not statistically significant (P = .07).
With the use of naturalistic driving methods in which crashes and near crashes involving older drivers are objectively measured as they occur on the road, associations have been identified between impaired contrast sensitivity, slowed visual processing speed, and impaired motion perception and an increased rate of a combined total of at-fault crashes and near crashes.
Background
This study aimed to evaluate the association between a Certified Driving Rehabilitation Specialist's (CDRS) ratings of on‐road driving performance by older drivers and at‐fault crash and ...near‐crash involvement using naturalistic driving techniques where crashes and near‐crashes are recorded in everyday driving through in‐vehicle instrumentation.
Methods
This is a cohort study of 144 drivers aged 70 years and over who were recruited due to a recent ophthalmology clinic visit at the University of Alabama at Birmingham. Baseline measurements consisted of demographics, visual status, and other health variables. At‐fault crashes and near‐crashes over 6 months were identified through instrumentation placed in their personal vehicle that recorded vehicle kinematics and video. After 6 months, a CDRS completed an on‐road assessment and provided a composite rating on specific driving behaviors and a global score.
Results
Rate ratios examining the association between older drivers with worse CDRS composite scores and rates of at‐fault crashes, at‐fault near‐crashes, and combined at‐fault crashes and near‐crashes were significantly higher compared to drivers with better scores. Results were similar for the CDRS global score.
Conclusions
Motor vehicle administrations use CDRS ratings to make decisions about licensure, and in clinical programs such as those based at rehabilitation clinics use them to make recommendations about fitness to drive and rehabilitation. This study suggests that these decisions and recommendations are valid from a safety standpoint.
Research on Alzheimer's disease (AD) and precursor states demonstrates a thinner retinal nerve fiber layer (NFL) compared to age-similar controls. Because AD and age-related macular degeneration ...(AMD) both impact older adults and share risk factors, we asked if retinal layer thicknesses, including NFL, are associated with cognition in AMD.
Adults ≥ 70 years with normal retinal aging, early AMD, or intermediate AMD per Age-Related Eye Disease Study (AREDS) nine-step grading of color fundus photography were enrolled in a cross-sectional study. Optical coherence tomography (OCT) volumes underwent 11-line segmentation and adjustments by a trained operator. Evaluated thicknesses reflect the vertical organization of retinal neurons and two vascular watersheds: NFL, ganglion cell layer-inner plexiform layer complex (GCL-IPL), inner retina, outer retina (including retinal pigment epithelium-Bruch's membrane), and total retina. Thicknesses were area weighted to achieve mean thickness across the 6-mm-diameter Early Treatment of Diabetic Retinopathy Study (ETDRS) grid. Cognitive status was assessed by the National Institutes of Health Toolbox cognitive battery for fluid and crystallized cognition. Correlations estimated associations between cognition and thicknesses, adjusting for age.
Based on 63 subjects (21 per group), thinning of the outer retina was significantly correlated with lower cognition scores (P < 0.05). No other retinal thickness variables were associated with cognition.
Only the outer retina (photoreceptors, supporting glia, retinal pigment epithelium, Bruch's membrane) is associated with cognition in aging to intermediate AMD; NFL was not associated with cognition, contrary to AD-associated condition reports. Early and intermediate AMD constitute a retinal disease whose earliest, primary impact is in the outer retina. Our findings hint at a unique impact on the brain from the outer retina in persons with AMD.
Progress toward treatment and prevention of age-related macular degeneration (AMD) requires imaging end points that relate to vision. We investigated choriocapillaris flow signal deficits (FD%) and ...visual function in eyes of individuals aged ≥60 years, with and without AMD.
One eye of each participant in the baseline visit of the Alabama Study on Early Age-Related Macular Degeneration 2 (ALSTAR2; NCT04112667) was studied. AMD presence and severity was determined using the Age-Related Eye Disease Study (AREDS) grading system. FD% was quantified using macular spectral domain optical coherence tomography angiography (OCTA) scans. Vision tests included rod-mediated dark adaptation (RMDA), best-corrected visual acuity, and contrast sensitivity (photopic and mesopic), and microperimetric light sensitivity (scotopic, mesopic, and photopic). Presence of subretinal drusenoid deposits (SDD) was determined using multimodal imaging.
In 410 study eyes of 410 participants (mean SD age = 71.7 years 5.9), FD% was higher in early AMD (mean SD = 54.0% 5.5, N = 122) and intermediate AMD (59.8% 7.4, N = 92), compared to normal (52.1% 5.3, N = 196) eyes. Among visual functions evaluated, RMDA showed the strongest association with FD% (r = 0.35, P < 0.0001), followed by contrast sensitivity (r = -0.22, P < 0.0001). Eyes with SDD had worse FD% (58.3% 7.4, N = 87), compared to eyes without SDD (53.4% 6.0, N = 323, P = < 0.0001).
Choriocapillaris FD% were associated with AMD severity and with impaired vision, especially RMDA. Reduced metabolic transport and exchange across the choriocapillaris-Bruch's membrane retinal pigment epithelium (RPE) complex, a causal factor for high-risk soft drusen formation, also may impair photoreceptor sustenance from the circulation. This includes retinoid resupply, essential to dynamic rod function.
Purpose
To assess associations between visual function and on‐road driving performance evaluated by a certified driving rehabilitation specialist (CDRS).
Methods
Adults aged 70 and older enrolled and ...completed assessments of visual acuity, contrast sensitivity, visual processing speed, visual field sensitivity, motion perception and spatial ability. At follow‐up, on‐road driving performance was evaluated on a 15‐mile route. Age‐adjusted odds ratios and 95% confidence intervals (95% CIs) were used to associate worse CDRS composite score and CDRS global rating for those with poorer visual function compared to those with better scores and ratings.
Results
For the 144 participants who enrolled, completed vision testing and the on‐road driving evaluation, the mean age was 79.2 (5.1) and 45.8% were female. The odds of worse CDRS global rating and composite score were significantly associated with moderately and severely impaired visual processing speed under divided attention (all p < 0.05). Those with poorer motion perception were at greater odds of a worse CDRS composite score (OR: 2.67, 95% CI: 1.14–6.26).
Conclusions
The CDRS composite score of on‐road driving performance by older adults was associated with slowed visual processing and impaired motion perception, suggesting that older driver performance, as rated by a CDRS, relies on visual skills. The CDRS global rating was also associated with impaired visual processing speed. The literature suggests impairments in these same visual functions elevate crash risk. While the results provide additional evidence suggesting these functional measures are associated with driving, further work is needed to identify and assess visual measures most closely related to driving safety and performance among older adults to better inform interventions, policy and future research.
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