GENERATION AND USE OF FUNCTIONALISED HYDROGELS THAT CAN RAPIDLY SAMPLE INFECTED SURFACES

This paper outlined our method for developing polymer-linked contact lens type materials for rapid detection and differentiation of Gram-positive, Gram-negative bacteria and fungi in infected corneas. It can be applied to both model synthetic or ex-vivo corneal models and has been successfully trialed in an initial efficacy tested animal study. First a hydrogel substrate for the swab material is selected, we have demonstrated selective swabs using a glycerol monomethacrylate hydrogel. Alternatively any commercial material with carboxylic acid functional groups is suitable but risks nonspecific adhesion. This is then functionalised via use of N-hydroxysuccinimide reaction with amine groups on the specified highly branched polymer ligand (either individually gram negative, gram positive or fungal binding polymers or a combination of all three can be employed for desired sensing application). The hydrogel is then cut into swabs suitable for sampling, used, and then the presence of gram positive, game negative and fungi are disclosed by the sequential addition of dyes (fluorescent vancomycin, fluorescein isothiocyanate and calcofluor white).

In summary this method presents:

Method to produce glycerol monomethacrylate hydrogels to minimize nonspecific binding

Methods of attaching pathogen binding highly branched polymers to produce selective hydrogel swabs

Method for disclosing bound pathogens to this swab using sequential dye addition

Pythium insidiosum keratitis - A review

Pythium insidiosum is an oomycete and is also called “parafungus” as it closely mimics fungal keratitis. The last decade saw an unprecedented surge in Pythium keratitis cases, especially from Asia and India, probably due to growing research on the microorganism and improved diagnostic and treatment modalities. The clinical features such as subepithelial infiltrate, cotton wool-like fluffy stromal infiltrate, satellite lesions, corneal perforation, endoexudates, and anterior chamber hypopyon closely resemble fungus. The classical clinical features of Pythium that distinguish it from other microorganisms are reticular dots, tentacular projections, peripheral furrowing, and early limbal spread, which require a high index of clinical suspicion. Pythium also exhibits morphological and microbiological resemblance to fungus on routine smearing, revealing perpendicular or obtuse septate or aseptate branching hyphae. Culture on blood agar or any other nutritional agar is the gold standard for diagnosis. It grows as cream-colored white colonies with zoospores formation, further confirmed using the leaf incarnation method. Due to limited laboratory diagnostic modalities and delayed growth on culture, there was a recent shift toward various molecular diagnostic modalities such as polymerase chain reaction, confocal microscopy, ELISA, and immunodiffusion. As corneal scraping (10% KOH, Gram) reveals fungal hyphae, antifungals are started before the culture results are available. Recent in vitro molecular studies have suggested antibacterials as the first-line drugs in the form of 0.2% linezolid and 1% azithromycin. Early therapeutic keratoplasty is warranted in nonresolving cases. This review aims to describe the epidemiology, clinical features, laboratory and molecular diagnosis, and treatment of Pythium insidiosum keratitis.

Posterior Reversible Encephalopathy Syndrome: An Unusual Complication of Benzodiazepine Poisoning: A Case Report

Posterior Reversible Encephalopathy Syndrome (PRES), also known as Reversible Posterior Leukoencephalopathy Syndrome, presents with rapid onset symptoms, including headache, seizures, altered consciousness, and visual disturbance. It is seen most frequently in settings of acute hypertension and is usually related to eclampsia. Only a few cases in the literature described PRES syndrome following benzodiazepines. We present a young male with benzodiazepine poisoning brought to the hospital in a deep coma, hypoxia, acidosis, and shock. Diagnosis of PRES was made on history, clinical examination, and radiologic findings of symmetric bilateral hyperintensities on T2 weighted Magnetic Resonance Imaging (MRIs) representing vasogenic edema.

Posterior Reversible Encephalopathy Syndrome: An Unusual Complication of Benzodiazepine Poisoning: A Case Report

Posterior Reversible Encephalopathy Syndrome (PRES), also known as Reversible Posterior Leukoencephalopathy Syndrome, presents with rapid onset symptoms, including headache, seizures, altered consciousness, and visual disturbance. It is seen most frequently in settings of acute hypertension and is usually related to eclampsia. Only a few cases in the literature described PRES syndrome following benzodiazepines. We present a young male with benzodiazepine poisoning brought to the hospital in a deep coma, hypoxia, acidosis, and shock. Diagnosis of PRES was made on history, clinical examination, and radiologic findings of symmetric bilateral hyperintensities on T2 weighted Magnetic Resonance Imaging (MRIs) representing vasogenic edema.

Clinical Utility of COVID-19 Real Time-Polymerase Chain Reaction Testing of Ocular Tissues of Non-COVID-19 Cornea Donors Deemed Suitable for Corneal Retrieval and Transplantation

PURPOSE

The purpose of this study was to evaluate the prevalence of SARS-CoV-2 in human postmortem ocular tissues of asymptomatic donors and its implications on our eye banking protocols.

METHODS

The expression of SARS-CoV-2 RNA was assessed by reverse transcription-polymerase chain reaction in corneal rims and conjunctival tissues from 100 donors who were found suitable for transplantation as per the donor screening guidelines of the Global Alliance of Eye Bank Associations. The donor's clinical history and cause of death were assessed for secondary analysis.

RESULTS

Of 200 ocular tissues (100 corneal and 100 conjunctival) from the same 1 eye of 100 surgical-intended donors, between September 2020 and April 2021, the overall positivity rate for SARS-CoV-2 was ∼1% (2/200). Both the ocular samples that tested positive were conjunctival biopsies (2/100, 2%), whereas corneal samples were negative (0/100, 0%) in both donors. The causes of donor death were trauma in 51 donors, suicide in 33, cardiac arrest in 7, electric shock in 5, metabolic cause in 2, malignancy in 1, and snake bite in 1. None of the donors had a medical history suggestive of COVID infection or possible contact. None of the recipients from the donors were reported to have any systemic adverse event after keratoplasty until the follow-up of 6 weeks.

CONCLUSIONS

The overall prevalence of SARS-CoV-2 was 1% (2% for conjunctival and 0% for corneal samples, P value = 0.5) in the donors who were found suitable for cornea recovery and transplantation. The findings of exceptionally low positive rates in our samples validate the criticality of history-based donor screening and do not support the necessity of postmortem PCR testing as a criterion for procurement and subsequent use for corneal transplantation.

Microneedle scleral patch for minimally invasive delivery of triamcinolone to the posterior segment of eye

The delivery of therapeutics to the posterior segment of the eye is achieved by invasive procedures, including intravitreal injections and implants. The topically applied formulations would not permeate through different tissue barriers of the eye to reach the posterior segment. Here, we demonstrate the effectiveness of microneedle scleral patch in delivering the model molecule, triamcinolone acetonide, to the posterior segment of the eye. Microneedle scleral patch (MSP) and microneedle corneal patch (MCP) were fabricated through the micromolding technique using rapidly dissolvable polyvinylpyrrolidone. The patches containing 25 microneedles were characterized for physical and mechanical properties, drug loading and release behavior in vitro and ex vivo porcine eye globe model. The distribution of TA administered using MSP and MCP in different ocular tissues was evaluated in the rabbit eye model. The results showed that microneedles with 545 ± 8 µm length and 279 ± 26 µm width at the base in MSP penetrate the scleral membrane with the application of 0.35 ± 0.06 N force. The needles dissolved within 60 s after insertion in the corneal and scleral tissue. The 5 min application of MSP showed a significantly (p < 0.05) greater TA disposition in the vitreous humor and choroid-retinal complex in excised porcine eye globe compared with MCP and TA nanosuspension eye drops. In rabbit model studies, the TA concentration was greatest in the choroid-retinal complex and sclera after administration through intravitreal injection and MSP, respectively. The TA disposition in the sclera was significantly (p < 0.05) greater after MSP application compared with intravitreal injection and MCP application for up to 24 h. MSP application provided a greater safety score compared with intravitreal injection. In conclusion, MSP can be developed as a minimally invasive drug delivery system to target the posterior segment of the eye.

Chronic groin pain in Desarda versus Lichtenstein hernia repair - a randomised controlled study

BACKGROUND: Chronic pain after inguinal hernia repair is a common complication. This study compared the difference between Desarda repair and Lichtenstein repair for inguinal hernia in chronic groin pain. METHODS: One hundred patients with unilateral uncomplicated inguinal hernia were randomised to either Desarda repair (n = 50) or Lichtenstein repair (n = 50) under local anaesthesia and were evaluated for pain postoperatively. Operative time, surgical complications, time to return to normal gait and work, and overall patient satisfaction were recorded. The patient was blinded to the procedure. Any pain at three months (numerical rating scale 1 or more) was considered chronic pain. RESULTS: Mean operation time was approximately 5 minutes less for Desarda (p = 0.33). There was no significant difference in terms of pain level postoperatively between Lichtenstein and Desarda groups. Twenty-two (44%) patients in the Lichtenstein group had chronic pain, and twenty-one (45.7%) patients had chronic pain in the Desarda group (p = 0.871). No significant difference was observed in haematoma formation, wound infection, recurrence rate, seroma, or foreign body sensation. The mean time for patients to return to normal gait was approximately 0.5 day earlier for the Desarda group (p = 0.29). The mean time for patients to return to normal work was comparable (p = 0.99). Desarda group had a slightly higher satisfaction rate than the Lichtenstein group (9.1%). CONCLUSION: Desarda repair is not inferior to Lichtenstein repair in the short-term concerning complications or pain.

Efficacy of voriconazole and amphotericin B in corneal preservative media

Purpose:

To evaluate the efficacy of voriconazole and amphotericin B in McCarey–Kaufman (MK) media.

Methods:

MK media vials were supplemented with either voriconazole at 1, 2, 20, 50, 100 μg/mL or amphotericin B at 0.5, 1, 2, 10, 20 μg/mL. The standard inoculum of the American Type Culture Collection (ATCC) strain of Candida albicans, Aspergillus flavus, and Fusarium keratinoplasticum was added to the set of vials. The efficacy outcomes were calculated as ‘viable fungal colony counts’ determined from the samples taken on Days 0 and 4. MK media containing fungal inoculum but without antifungal supplements were used as control.

Results:

In the voriconazole arm, on Day 4, a reduction in the colony count was observed for Candida albicans (1 μg/mL, 36%; 100 μg/mL, 100%), Aspergillus flavus (1 μg/mL, 53.8%; 100 μg/mL, 80.4%), and Fusarium keratinoplasticum (1 μg/mL, 39.0%; 100 μg/mL, 72.2%). Similarly, in the amphotericin B arm, on Day 4, a reduction in the colony count was observed for Candida albicans (0.5 μg/mL; 99.9%; 20 μg/mL, 100%), Aspergillus flavus (0.5 μg/mL, 65.2%; 20 μg/mL, 84.8%), and Fusarium keratinoplasticum (0.5 μg/mL, 90.1%; 20 μg/mL, 100%).

Conclusion:

Compared to voriconazole, the addition of amphotericin B significantly reduces fungal contamination in MK media.

Evaluation of ligand modified poly (N-Isopropyl acrylamide) hydrogel for etiological diagnosis of corneal infection

Corneal ulcers, a leading cause of blindness in the developing world are treated inappropriately without prior microbiology assessment because of issues related to availability or cost of accessing these services.

In this work we aimed to develop a device for identifying the presence of Gram-positive or Gram-negative bacteria or fungi that can be used by someone without the need for a microbiology laboratory. Working with branched poly (N-isopropyl acrylamide) (PNIPAM) tagged with Vancomycin, Polymyxin B, or Amphotericin B to bind Gram-positive bacteria, Gram-negative bacteria and fungi respectively, grafted onto a single hydrogel we demonstrated specific binding of the organisms. The limit of detection of the microbes by these polymers was between 10 and 4 organisms per high power field (100X) for bacteria and fungi binding polymers respectively. Using ex vivo and animal cornea infection models infected with bacteria, fungi or both we than demonstrated that the triple functionalised hydrogel could pick up all 3 organisms after being in place for 30 min. To confirm the presence of bacteria and fungi we used conventional microbiology techniques and fluorescently labelled ligands or dyes.

While we need to develop an easy-to-use either a colorimetric or an imaging system to detect the fluorescent signals, this study presents for the first time a simple to use hydrogel system, which can be applied to infected eyes and specifically binds different classes of infecting agents within a short space of time. Ultimately this diagnostic system will not require trained microbiologists for its use and will be used at the point-of-care.

•

Functionalised branched Poly N-isopropyl acrylamide binds corneal ulcer causing microorganisms.

•

The functionalised polymers demonstrated specific binding to gram positive, gram negative and fungi.

•

Grafting three different polymers on a single hydrogel retained this specific binding for microorganisms.

•

Triple functionalised hydrogels were effective in picking up microorganisms in ex-vivo and animal cornea infection models.

•

Application for a duration of 30 min was sufficient to pick up enough organisms for subsequent identification.

Application of Trypan Blue Stain in the Microbiological Diagnosis of Infectious Keratitis-A Case Series

PURPOSE

The purpose of this study was to report 3 cases of microbial keratitis, wherein trypan blue staining was used to aid the microbiological diagnosis of fungal keratitis and Pythium keratitis in a rural setup.

METHODS

Three consecutive patients who presented with a diagnosis of infectious keratitis underwent corneal scraping, and the smears were assessed using trypan blue stain and potassium hydroxide (KOH) mount.

RESULTS

Of the 3 cases, the first 2 cases showed septate fungal filaments in trypan blue-stained preparation and KOH mount. Case 3 showed the presence of broad aseptate filaments with ribbon-like folds on both KOH mount and trypan blue stain, consistent with the diagnosis of Pythium keratitis. The first 2 cases improved with topical and systemic antifungals. Case 1 healed with scarring at 7 weeks with improvement in best-corrected visual acuity (BCVA) to 20/60. Case 2 healed within 2 weeks, and BCVA improved to 20/40. Case 3 received topical linezolid (0.2%), azithromycin eye ointment, and oral azithromycin. At 5 weeks the infection decreased but thinning was noted, which necessitated tissue adhesive and bandage contact lens application. Scarring was noted at 10 weeks, and BCVA improved to 20/40.

CONCLUSIONS

In this case series, trypan blue staining showed promising results in the easy identification of aseptate and septate fungal elements. This is the first case series showing the utility of this stain in the management of microbial keratitis.

Year one of COVID-19 pandemic in India: Effect of lockdown and unlock on trends in keratoplasty at a tertiary eye centre

PURPOSE

To describe the impact of lockdown and unlock phases of the COVID-19 pandemic on keratoplasty trends at a tertiary eye care center in India.

METHODS

This cross-sectional hospital-based study included 6,277 patients presenting between March 25, 2017 and March 31, 2021. The data of the patients who underwent keratoplasty during the lockdown and unlock phases were compared with the respective periods in the previous three years before COVID-19.

RESULTS

During the year one of pandemic, there was a 29.46% decline in the total number of keratoplasty performed at the institute compared to previous year's annual numbers. The patients undergoing keratoplasty decreased by 90.28% (28/288) of pre-COVID-19 volumes during the lockdown phase. This was mainly because of a 40.6% reduction in the proportion of patients requiring interstate travel. There was complete recovery in the number of patients undergoing keratoplasty to 129.27% (184/142) of pre-COVID-19 volumes by March 2021. This gradual incremental trend was seen across all types of keratoplasty in Descemet stripping endothelial keratoplasty (135.29%), penetrating keratoplasty (117.6%), therapeutic keratoplasty (122.22%), anterior lamellar keratoplasty (150%), and Descemet membrane endothelial keratoplasty (141.18%) by March 2021 with the gradual ease of lockdown regulations. The eye bank affiliated to the institute saw a 55.44% decline in donor cornea collection and an increase in utilization rate from 58.12% in previous years to 83.78% in year one of the pandemic. The overall eye bank donor cornea collection recovered to 86.96% (627/721) and tissue utilization increased by 109.99% (455/414) by March 2021.

CONCLUSION

The first year of the COVID-19 pandemic saw an overall reduction of 29.46% of the patients undergoing keratoplasty at the institute. There was a gradual and incremental increase in all types of keratoplasty in the unlock phase, which surpassed the preceding years' monthly numbers in February and March.

Changing trend in the morphology of cataracts at a tertiary eye care centre in South India due to COVID-19-pandemic related national lockdown

Purpose:

To study the changing trends in the morphology of cataracts at a tertiary eye care center in South India due to COVID-19 pandemic-related national lockdown.

Methods:

A retrospective study conducted at a tertiary eye care center in Andhra Pradesh state of South India, which included 1724 patients (1753 eyes) who underwent cataract surgery at our center during April 2019–July 2019 (1298 eyes of 1271 patients) and April 2020–July 2020 (455 eyes of 453 patients). Factors studied included preoperative lens status, associated phacodonesis or subluxation, pupil size, other eye lens status, associated retinal problems, glaucoma, and complications during surgery. Postoperative uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), corneal clarity, intraocular pressure (IOP), and disc status at postoperative day 1, 1 week, and 1-month visits were compared.

Results:

A significantly lower proportion of nuclear sclerosis (decreased from 83.2% in last year before lockdown to 55.2% during lockdown) and significantly higher proportions of mature, brown, or black cataract and phacomorphic, phacolytic, or Morgagnian cataract (increased from 15.5% in last year before lockdown to 43.8% during lockdown) were observed. The proportion of small-incision cataract surgery decreased significantly (from 63.2% to 57.4%), whereas the proportion of phacoemulsification increased significantly (from 35.9% to 41.5%) during lockdown as compared to last year. A significantly higher proportion of eyes with small pupils and association with retinal pathology were also observed during the lockdown.

Conclusion:

During the national lockdown, there was a shift from nuclear sclerosis grade toward mature, brown, black grade of cataracts. In addition, the proportion of small-incision cataract surgery decreased significantly whereas the proportion of phacoemulsification increased significantly during the lockdown. More number of cataracts with small pupils and associated retinal pathology were observed during the lockdown.

Probing Gluon Spin-Momentum Correlations in Transversely Polarized Protons through Midrapidity Isolated Direct Photons in p^{↑}+p Collisions at sqrt[s]=200 GeV

Studying spin-momentum correlations in hadronic collisions offers a glimpse into a three-dimensional picture of proton structure. The transverse single-spin asymmetry for midrapidity isolated direct photons in p^{↑}+p collisions at sqrt[s]=200  GeV is measured with the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). Because direct photons in particular are produced from the hard scattering and do not interact via the strong force, this measurement is a clean probe of initial-state spin-momentum correlations inside the proton and is in particular sensitive to gluon interference effects within the proton. This is the first time direct photons have been used as a probe of spin-momentum correlations at RHIC. The uncertainties on the results are a 50-fold improvement with respect to those of the one prior measurement for the same observable, from the Fermilab E704 experiment. These results constrain gluon spin-momentum correlations in transversely polarized protons.

Left ventricular blood flow energetics after acute ST-segment elevation myocardial infarction associate with left ventricular remodeling

Background

Myocardial infarction (MI) leads to complex changes in left ventricular (LV) haemodynamics. It remains unknown how four-dimensional (4D) acute changes in LV blood flow kinetic energy (KE) affect LV remodeling. We hypothesized that LV blood flow energetics are independently associated with adverse LV-remodeling.

Methods

In total, 69 revascularised ST-segment elevation MI patients were enrolled. All patients underwent cardiovascular magnetic resonance (CMR) examination within 2 days of the index event and at 3-month. CMR examination included cine, late gadolinium enhancement, and whole-heart 4D flow acquisitions. CMR analysis included: LV volumes, function, infarct size (indexed to body surface area), microvascular obstruction (MVO), two-dimensional, retrospective valve tracking derived mitral inflow metrics, and 4D blood flow KE components (Fig. 1). Adverse LV-remodeling was defined and categorized according to increase in LV end-diastolic volume: 10% (mild), 15% (moderate), and 20% (severe).

Results

Twenty-four patients (35%) developed mild, 17 patients (25%) moderate, 11 patients (16%) severe LV remodeling. Demographics and clinical history were comparable between patients with/without LV remodeling. In univariable logistic regression analysis, A-wave KE was associated with mild, moderate, and severe LV remodeling (p=0.03, p=0.02, p=0.02, respectively), whereas infarct size was associated with only mild LV remodeling (p=0.02). In multivariable logistic regression analysis, whilst the infarct size and A-wave KE were identified as independent markers for mild LV remodeling (p=0.03, p=0.09, respectively), A-wave KE was the only independent marker regarding moderate and severe LV remodeling (both, p&lt;0.01). In ROC analysis for A-wave KE to be associated with the presence of adverse LV remodeling, the area under the curve was 0.67 for mild (p=0.02), 0.70 for moderate (p=0.01), 0.71 for severe (p=0.03) LV remodeling.

Conclusion

In patients with STEMI, LV hemodynamics assessment by LV blood flow KE demonstrated an incremental value to predict adverse LV-remodeling. A-wave KE early after acute MI had an independent effect on adverse LV remodeling.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported by the British Heart Foundation [FS/10/62/28409 to S.P.] and Dutch Technology Foundation (STW), project number 11626 (JW, ME).

High interstudy repeatability of automatic deep learnt biventricular CMR measurements

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Wellcome Trust (UK), NIHR (UK)

Introduction

Cardiac magnetic resonance (CMR) measurements have significant diagnostic and prognostic value. Accurate and repeatable measurements are essential to assess disease severity, evaluate therapy response and monitor disease progression. Deep learning approaches have shown promise for automatic left ventricular (LV) segmentation on CMR, however fully automatic right ventricular (RV) segmentation remains challenging. We aimed to develop a biventricular automatic contouring model and evaluate the interstudy repeatability of the model in a prospectively recruited cohort.

Methods

A deep learning CMR contouring model was developed in a retrospective multi-vendor (Siemens and General Electric), multi-pathology cohort of patients, predominantly with heart failure, pulmonary hypertension and lung diseases (n = 400, ASPIRE registry). Biventricular segmentations were made on all CMR studies across cardiac phases. To test the accuracy of the automatic segmentation, 30 ASPIRE CMRs were segmented independently by two CMR experts. Each segmentation was compared to the automatic contouring with agreement assessed using the Dice similarity coefficient (DSC). 

A prospective validation cohort of 46 subjects (10 healthy volunteers and 36 patients with pulmonary hypertension) were recruited to assess interstudy agreement of automatic and manual CMR assessments. Two CMR studies were performed during separate sessions on the same day. Interstudy repeatability was assessed using intraclass correlation coefficient (ICC) and Bland-Altman plots. 

Results

DSC showed high agreement (figure 1) comparing automatic and expert CMR readers, with minimal bias towards either CMR expert. The scan-scan repeatability CMR measurements were higher for all automatic RV measurements (ICC 0.89 to 0.98) compared to manual RV measurements (0.78 to 0.98). LV automatic and manual measurements were similarly repeatable (figure 2). Bland-Altman plots showed strong agreement with small mean differences between the scan-scan measurements (figure 2).

Conclusion

Fully automatic biventricular short-axis segmentations are comparable with expert manual segmentations, and have shown excellent interstudy repeatability.

Left ventricular four-dimensional blood flow energetics and vorticity in chronic myocardial infarction patients with/without left ventricular thrombus

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): The British Heart Foundation [FS/10/62/28409] and Dutch ZonMw [104003001].

Background

Left ventricular thrombus (LVT) formation is a frequent and serious complication of myocardial infarction (MI). How global LV flow characteristics are related to this phenomenon is yet uncertain. In this study, we investigated LV flow differences using 4D flow cardiovascular magnetic resonance (CMR) between chronic MI patients with LVT [MI-LVT(+)] and without LVT [MI-LVT(-)], and healthy controls.

Methods

In this prospective cohort study, the 4D flow CMR data were acquired in 19 chronic MI patients (MI-LVT(+), n= 9 and MI-LVT(-), n= 10) and 9 age-matched controls. All included subjects were in sinus rhythm. The following LV flow parameters were obtained: LV flow components (direct, retained, delayed, residual), mean and peak KE values (indexed to instantaneous LV volume), mean and peak vorticity values, and diastolic vortex ring properties (position, orientation, shape).

Results

The MI patients demonstrated a significantly larger amount of delayed and residual flow, and a smaller amount of direct flow compared to controls (p = 0.02, p = 0.03, and p &lt; 0.001, respectively). The MI-LVT(+) patients demonstrated numerically increased residual flow and reduced retained and direct flow in comparison to MI-LVT(-) patients. Systolic mean and peak LV blood flow KE values were significantly lower in MI patients compared to controls (p = 0.04, p = 0.03, respectively). Overall, the mean and peak LV vorticity values were significantly lower in MI patients compared to controls. The mean vorticity at the basal level was significantly higher in MI-LVT(+) than in MI-LVT(-) patients (p &lt; 0.01). The vortex ring core during E-wave in MI-LVT(-) group was located closer to the mitral annulus and in a less tilted orientation to the LV compared to MI-LVT(+) group (p = 0.05, p &lt; 0.01, respectively).

Conclusion

Chronic MI patients with LVT express a different distribution of LV flow components, irregular vorticity vector fields, and altered diastolic vortex ring geometric properties as assessed by 4D flow CMR. Larger prospective studies are warranted to further evaluate these initial observations.

Fully automated CMR derived stroke volume correlates with right heart catheter measurements in patients with suspected pulmonary hypertension

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Welcome Trust (UK), NIHR (UK)

Introduction

Cardiac magnetic resonance (CMR) assessment plays a significant role in the diagnosis, prognosis and monitoring of patients with pulmonary hypertension (PH). We developed a deep learning model to automatically generate biventricular contours and validated its result in a prospective cohort of patients with suspected PH who underwent right heart catheterization (RHC).

Methods

A deep learning CMR contouring model was developed in a retrospective multi-vendor (Siemens and General Electric), multi-pathology cohort of patients, predominantly with heart failure, lung disease and PH (n = 400, ASPIRE registry). Biventricular segmentations were made on all CMR studies across cardiac phases. A prospective validation cohort of 102 suspected PH patients was recruited and they had RHC within 24 hours  of the CMR. To test the accuracy of the automatic segmentation, the RHC-thermodilution and CMR-derived measures of stroke volume (SV) were compared for manual and automated measurements. 

Results

The mean and standard deviation for the derived SV was 59 ml ± 21 measured by RHC and 75 ml ± 25 for automated and 79 ml ± 26 for manual CMR measurements. Automatic and manual CMR measurement correlated strongly with RHC derived SV; 0.73, 95% CI [0.62, 0.81] and 0.78, 95% CI [0.69, 0.85], respectively (figure 1).  The agreement between automatic and manual SV was high; interclass correlation coefficient (ICC) = 0.88, 95% CI [0.83, 0.92] and Bland-Altman plots showed a narrow spread of mean differences between manual and automatic measurements (figure 2).

Conclusion

In a prospective cohort, fully automatic CMR assessments corresponded accurately to invasive hemodynamics performed within 24 hours of a CMR study.

Hospital Cornea Retrieval Programme in a startup eye bank - A retrospective analysis and lessons learned

Purpose:

This study aimed to share our experience in the hospital cornea retrieval program as a new eye bank.

Methods:

This was a retrospective study conducted in a tertiary care institute from August 26, 2019 to March 22, 2020. The medical and eye bank records were analyzed for hospital mortality, mortuary records, and donors approached. The corneal collection was divided between Voluntary (received from voluntary calls), HCRP (cornea received from hospital deaths), and Medico-Legal Cases (received from MLC deaths in hospital) to see the trend of donation and utilization over time.

Results:

During the study period, 154 corneas (77 pairs) were collected. The HCRP provided a major source of corneas 58.4% (90 corneas) as compared to voluntary 19.5% (30 corneas) and MLC 22.1%(34 corneas). There were younger tissues in MLC than HCRP donors, and older tissues in Voluntary donors, and the difference was statistically significant. There was no significant difference in the quality of optical grade tissues and the utilization of corneas for transplants between the three groups. Post hoc analysis showed more non-optical tissues in the voluntary donations (P = 0.004), maximum donors with medical contraindications in the HCRP group (P = 0.001), and time-lapse in corneal retrieval in MLC cases (P = 0.0001). Of these 154 corneas, 78 (50.6%) were assessed as suitable for transplantation, of which 59 (75.6%) tissues were optical grade tissues. The overall utilization was 39.6%.

Conclusion:

HCRP is indeed challenging for a new eye bank, but proper understanding and implementing strategies may help for good utilization of tissues.

Impact of COVID-19 related national lockdown on care of corneal transplantation patients at a tertiary eye care centre in India

Purpose

To study impact of COVID-19 related national lockdown on care of corneal transplantation patients at a tertiary eye centre in Andhra Pradesh state of South India.

Methods

Cross-sectional questionnaire-based study conducted at tertiary eye care centre in Andhra Pradesh state of South India, included 109 patients who underwent keratoplasty(full thickness or partial thickness) at our centre and who came for follow-up visit after lockdown. Factors such as type, indication, number of keratoplasties in the operated eye, and unusual clinical outcomes identified during visit after the lockdown, were studied. Uncorrected visual acuity, best corrected visual acuity, clarity of graft, graft-host junction apposition, intactness of sutures, intraocular pressure and disc status were compared on visits made before and after lockdown.

Results

During lockdown, 77.1% patients were properly using medications that was significantly (P = 0.0003) lower than that of before the lockdown (90.8%). After the lockdown, 82.3% patients were using medications properly that was comparable (P = 0.11) to that of during the lockdown (77.1%). The proportion of eyes with clear grafts and intact sutures decreased significantly after lockdown. The unusual outcomes observed after the lockdown were graft failure (36.7%), graft edema (11%), graft infiltrate(5.5%), phthysis bulbi (1.85%) and edematous graft cleared in eyes 3.7% eyes.

Conclusion

We noted significant drop in usage of medications from 91% before lockdown to 77% during lockdown and maintained at 83% after lockdown. Edematous grafts increased from 41% before lockdown to 54% after the lockdown. Intactness of sutures decreased from 82% before lockdown to 69% after lockdown.

Keratitis following laser refractive surgery: Clinical spectrum, prevention and management

Laser refractive surgery (LRS) is one of the most demanding areas of ophthalmic surgery and high level of precision is required to meet outcome expectations of patients. Post-operative recovery is of vital importance. Keratitis occurring after LRS can delay visual recovery. Both surface ablations [Photorefractive keratectomy (PRK)] as well as flap procedures [Laser in-situ keratomileusis (LASIK)/Small incision lenticule extraction] are prone to this complication. Reported incidence of post-LRS infectious keratitis is between 0% and 1.5%. The rate of infections after PRK seems to be higher than that after LASIK. Staphylococci, streptococci, and mycobacteria are the common etiological organisms. About 50–60% of patients present within the first week of surgery. Of the non-infectious keratitis, diffuse lamellar keratitis (DLK) is the most common with reported rates between 0.4% and 4.38%. The incidence of DLK seems to be higher with femtosecond LASIK than with microkeratome LASIK. A lot of stress is laid on prevention of this complication through proper case selection, asepsis, and use of improved protocols. Once keratitis develops, the right approach can help resolve this condition quickly. In cases of suspected microbial keratitis, laboratory identification of the organism is important. Most lesions resolve with medical management alone. Interface irrigation, flap amputation, collagen cross-linking and therapeutic penetrating keratoplasty (TPK) are reserved for severe/non-resolving cases. About 50–75% of all infectious keratitis cases post LRS resolve with a final vision of 20/40 or greater. Improved awareness, early diagnosis, and appropriate intervention can help limit the damage to cornea and preserve vision.