Short-term response to anti-VEGF as indicator of visual prognosis in refractory age-related macular degeneration

BACKGROUND

Some patients with neovascular age-related macular degeneration (nAMD) respond insufficiently to anti-VEGF treatment despite maximal monthly intravitreal injections. Their short-term response between injections was investigated for extent and visual prognosis.

SUBJECTS/METHODS

Monocentric retrospective observational study. 45 eyes from 41 patients with refractory nAMD (who previously received at least 12 months of anti-VEGF treatment), evaluated by optical coherence tomography (OCT) in between monthly anti-VEGF injections. The fluid profile on OCT was evaluated before, 1 week after, and 1 month after an intravitreal injection, using central retinal thickness (CRT), manual measurements, and fluid specific volumetric measurements performed by an automated algorithm based on artificial intelligence.

RESULTS

A significant improvement was found at week 1 in terms of CRT (p < 0.0001), intraretinal (IRF) (p = 0.007), subretinal fluid (SRF) (p < 0.0001), and pigment epithelium detachment (PED) volume (p < 0.0001). Volumetric fluid measures revealed a >50% reduction at week 1 for both IRF and SRF for approximately two-thirds of eyes. Poorer short-term response was associated with larger exudative fluid amounts (IRF + SRF) (p = 0.003), larger PED (p = 0.007), lower visual acuity (p = 0.004) and less anatomic changes at treatment initiation (p < 0.0001). Univariate and multivariate analysis revealed that visual outcomes 4 and 5 years later was significantly worse with weaker short-term responsiveness (p = 0.005), with the presence of atrophy (p = 0.01) and larger PED volumes (p = 0.002).

CONCLUSIONS

Incomplete responders to anti-VEGF showed a significant short-term response, identifiable at 1 week after injection, with rapid recurrence at 1 month. Weaker short-term responsiveness at 1 week was associated with poorer long term visual prognosis. These patients may need adjuvant treatment to improve their prognosis.

In Vivo Retinal Pigment Epithelium Imaging using Transscleral Optical Imaging in Healthy Eyes

Objective

To image healthy retinal pigment epithelial (RPE) cells in vivo using Transscleral OPtical Imaging (TOPI) and to analyze statistics of RPE cell features as a function of age, axial length (AL), and eccentricity.

Design

Single-center, exploratory, prospective, and descriptive clinical study.

Participants

Forty-nine eyes (AL: 24.03 ± 0.93 mm; range: 21.9-26.7 mm) from 29 participants aged 21 to 70 years (37.1 ± 13.3 years; 19 men, 10 women).

Methods

Retinal images, including fundus photography and spectral-domain OCT, AL, and refractive error measurements were collected at baseline. For each eye, 6 high-resolution RPE images were acquired using TOPI at different locations, one of them being imaged 5 times to evaluate the repeatability of the method. Follow-up ophthalmic examination was repeated 1 to 3 weeks after TOPI to assess safety. Retinal pigment epithelial images were analyzed with a custom automated software to extract cell parameters. Statistical analysis of the selected high-contrast images included calculation of coefficient of variation (CoV) for each feature at each repetition and Spearman and Mann-Whitney tests to investigate the relationship between cell features and eye and subject characteristics.

Main Outcome Measures

Retinal pigment epithelial cell features: density, area, center-to-center spacing, number of neighbors, circularity, elongation, solidity, and border distance CoV.

Results

Macular RPE cell features were extracted from TOPI images at an eccentricity of 1.6° to 16.3° from the fovea. For each feature, the mean CoV was < 4%. Spearman test showed correlation within RPE cell features. In the perifovea, the region in which images were selected for all participants, longer AL significantly correlated with decreased RPE cell density (R Spearman, Rs = -0.746; P < 0.0001) and increased cell area (Rs = 0.668; P < 0.0001), without morphologic changes. Aging was also significantly correlated with decreased RPE density (Rs = -0.391; P = 0.036) and increased cell area (Rs = 0.454; P = 0.013). Lower circular, less symmetric, more elongated, and larger cells were observed in those > 50 years.

Conclusions

The TOPI technology imaged RPE cells in vivo with a repeatability of < 4% for the CoV and was used to analyze the influence of physiologic factors on RPE cell morphometry in the perifovea of healthy volunteers.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Fluid dynamics between injections in incomplete anti-VEGF responders within neovascular age-related macular degeneration: a prospective observational study

Background

The purpose of the study was to investigate the short-term response profile after an intravitreal injection (IVI) of anti-vascular endothelial growth factor (VEGF) in patients with neovascular age-related macular degeneration (nAMD) and incomplete response to anti-VEGF.

Methods

In this monocentric prospective observational study, we recruited patients with incomplete response to anti-VEGF, defined as presence of subretinal fluid (SRF) and/or intraretinal fluid (IRF) on optical coherence tomography (OCT) for at least 6 months despite monthly anti-VEGF treatment. Each patient underwent complete ophthalmic exam and imaging study (including OCT, fluorescein angiography, indocyanine green angiography, OCT-angiography) the day of their scheduled monthly IVI. Intermediate visits were performed weekly thereafter (comprising ophthalmic exam and OCT), until week 4. Fluid metrics were quantified using an artificial intelligence-based algorithm at baseline and at each subsequent weekly visit. Main outcomes were residual fluid volumes of SRF and IRF for each time point, and its relative change after treatment. Particular interest was given to each patients’ nadir point, which was used for association analysis with imaging parameters.

Results

A total of 28 eyes of 26 patients were included into the study. The maximal response was reached at 1.93 weeks on average. The relative fluid resolution at nadir point was 66 ± 36.7%, with quartile limits at 49.1%, 83%, and 96.1%, respectively. Mean residual fluid volume was 64.9 ± 128.8 µl at nadir point. Residual fluid was positively correlated with baseline SRF (r = 0.76, p < 0.0001) and larger pigment epithelium detachment (r = 0.65, p = 0.0001). Polypoidal choroidal vasculopathy was associated with larger residual fluid (p = 0.0013).

Conclusions

Incomplete anti-VEGF responders in nAMD showed significant mean fluid resolution between injections, typically after 2 weeks. However, complete resolution was the exception, and the amount of residual fluid varied greatly. To understand the role of the unresponsive fluid, further studies are needed.

669 Mortality Risk Prediction for Emergency Laparotomy: Are We Utilising the Best Tool?

Aim

Emergency laparotomy is one of the common operations performed in the UK. To aid in more objective decision making, several scoring systems have been formulated. In this project, we aimed to explore the predictive power of both NELA and P-Possum mortality scores against 30 days and 90 days observed mortality for emergency laparotomy patients.

Method

Patient details from two large district general hospitals were extracted from the NELA database over a period of three years. Pre-operative NELA, post-operative NELA, and P-POSSUM predicted mortality were calculated and compared with the observed 30 days and 90 days mortality for the entire cohort. Model discrimination (statistical accuracy) was tested by calculating the area under the receiver operating characteristic curve (AUC), which was used to assess how accurately the model could discriminate.

Results

There were 378 patients eligible for inclusion with a median age of 64. 39 patients (10.3%) died within 30 days and 52 patients (13.8%) died within 90 days. P-POSSUM score, pre-operative NELA, and post-operative NELA scores predicted the 30 days mortality as (2.7%, 3.7%, and 2.4%) and 90 days mortality as (2.9%, 4.8%, and 4%) respectively. The discriminative power for 30 days and 90 days mortality was highest for the pre-operative NELA score (AUC 0.870, CI: 0.824 – 0.916), (AUC 0.826, CI: 0.769 – 0.884) respectively.

Conclusions

Both NELA and P-Possum scores underpredicted actual 30 days and 90 days mortality. It was however noted that the pre-operative NELA mortality score showed more accurate mortality discriminative power than the other 2 tested tools.

1176 Paediatric Patients Presented with Right Iliac Fossa Pain: Is the Ultrasound Scan Conducted in A Timely Manner?

Aim

Ultrasound scan is a crucial clinical tool in the management of acute appendicitis in children. That is because it can aid in the diagnosis without exposing the patient to potentially harmful ionising radiation from computed tomography scans. In this project, we were assessing whether children presented with right iliac fossa pain receive their scans on time. In addition, we were exploring whether definitive management and hospital length of stay were affected by the scan delay.

Method

This was a retrospective project in which we assessed case notes of paediatric patients who had an ultrasound scan between September 2019 and September 2020 in one of the district general hospitals in the UK. The project included notes of patients who were below 16, admitted with right iliac fossa pain, and had an inpatient ultrasound scan.

Results

A total of 33 patients met the inclusion criteria. The waiting time ranged from 1 hour to 89 hours with a mean of around 19.5 hours and a median of 14.5 hours. The hospital length of stay ranged from 1 day to 21 days with a mean of around 2.5 days and a median of 1 day.

Conclusions

An ultrasound scan should be conducted within the same day of admission for all paediatric patients presented with right iliac fossa pain.

Tuning electrical and thermal conductivities of the two-dimensional electron gas in AlN/GaN heterostructures by piezoelectricity

We investigate the electrical and thermal conductivities of the two-dimensional electron gas (2DEG) confined in the quantum well formed at the heterojunction between a thin GaN layer and an AlN layer strained by an Al _x Ga_1-x N capping layer in the temperature range from 10 to 360 K. The experimental protocol developed to deduce from calorimetric and Hall-effect measurements at a variable temperature the critical characteristics and transport properties of the confined 2DEG is presented. It is found that, in the measured temperature range (10-360 K), the electrical conductivity of the 2DEG is temperature-independent, due to the predominance of scattering processes by interface defects. However, the thermal conductivity shows a linear temperature dependence, mirroring the specific heat of free electrons. The temperature-independent relaxation time associated with the overall electron scattering means that the values obtained for electrical and thermal conductivities are in excellent agreement with those stipulated by the Weidemann-Franz law. It is also found that for weak strain fields in the AlN layer, both the electrical and thermal conductivities of the two-dimensional interfacial electrons increase exponentially with strain. The importance of 2DEG in AlN/GaN quantum wells lies in the fact that the strong piezoelectricity of AlN allows the transport properties of the 2DEG to be tuned or modulated by a weak electric field even with the high density of lattice mismatch induced defects at the AlN-GaN interface .

Endovascular treatment of very small intracranial aneurysms

The endovascular treatment of intracranial aneurysms 3 mm or less is considered controversial. The purpose of this study is to report angiographic and clinical results following coiling of such aneurysms and compare them to those of larger aneurysms (> 3 mm).Between November 1999 and November 2009 endovascular treatment was attempted in 956 consecutive intracranial aneurysms. Of 956 aneurysms, 111 aneurysms were very small aneurysms with a maximal diameter of 3 mm or less. We conducted a retrospective analysis of angiographic and clinical outcome following coiling of very small aneurysms and subsequently comparing it to the results of larger aneurysms.Coiling initially failed in eight aneurysms. In the remaining 103 aneurysms endovascular treatment was accomplished and immediate angiographic results showed complete aneurysm occlusion in 43 aneurysms, nearly complete aneurysm occlusion in 54 aneurysms and less than 90% aneurysm occlusion in six aneurysms. Complications occurred in the treatment of 15 aneurysms, including eight procedural ruptures, six thromboembolic events and one case of early hemorrhage. Compared with larger aneurysms, treatment of very small aneurysms was associated with a higher rate of procedural ruptures (7.2% versus 4.4%) and procedural mortality (4.7% versus 2.7%) but a lower procedural morbidity (1.9% versus 4.0%). However none of these differences reached statistical significance (p = 0.186, p= 0.388, respectively). The retreatment rate was higher for the larger aneurysms (8.2% and 6.3%), but this was not significant either (p= 0. 496). At nine-month follow-up significantly more small aneurysms were found to have a stable occlusion grade compared to large aneurysms.Endovascular treatment of very small aneurysms is feasible with a lower retreatment rate compared to large aneurysms (> 3 mm). However the data also suggest that endovascular treatment of very small aneurysms might be associated with an increased risk of procedural ruptures and mortality. At nine-month follow-up results indicate significantly less compaction in the very small aneurysms.

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