Localizing Thalamomesencephalic Afferent and Efferent Pupillary Defects.

ABSTRACT: A 42-year-old Algerian man presented for binocular oblique diplopia, hypersomnolence with drop attacks, bilateral hearing loss, and thoracic pain. He had a right thalamomesencephalic hemorrhage due to an underlying cavernous malformation treated with subtotal surgical resection. On neuro-ophthalmic examination, the patient had a left relative afferent pupillary defect and a right oculosympathetic efferent pupillary defect (i.e., Horner syndrome) in addition to other thalamomesencephalic eye and neurologic signs (right fourth nerve palsy, hearing loss, hemiparesis, and thalamic pain). Clinicians should recognize the localizing value of this unique constellation of mesencephalic afferent and efferent pupillary defects.

Single transient intraocular pressure elevations cause prolonged retinal ganglion cell dysfunction and retinal capillary abnormalities in mice.

Transient intraocular pressure (IOP) elevations are likely to occur in certain forms of glaucoma and after intravitreal injections to treat various retinal diseases. However, the impact of these transient IOP elevations on the physiology of individual retinal ganglion cells (RGCs) is unknown. In this report, we explore how transient IOP elevations in mice affect RGC physiology, RGC anatomy, and retinal arteriole and capillary structure. Transient IOP elevation was induced in 12-week old wild type C57BL6J mice by injecting sodium hyaluronate into the anterior chamber. IOP was measured immediately after the injection and again 1 and 7 days later. Average peak IOP after injection was ~50 mmHg and subsequent IOPs returned to normal. RGC physiology was assessed with a multielectrode array (MEA) by calculating a spike triggered average (STA) at the same time points. RGC counts and retinal vascular structure were assessed 14 days after injection with immunohistochemistry to label RGCs and blood vessels. Transient IOP elevation caused a marked reduction of scotopic STA presence and delayed center and surround STA peak times that did not recover. Transient IOP elevation also caused a reduced photopic receptive field size and spontaneous firing rate, both of which showed some recovery with time. Transient IOP elevation also induced vascular remodeling: the number of capillary branches was decreased within the superficial and intermediate vascular plexi. RGC counts, retinal arteriole diameter, and deep capillary plexus branching were unaffected. These previously unappreciated findings suggest that transient IOP elevation may cause unrecognized and potentially long-term pathology to RGCs and associated neurovascular units which should be accounted for in clinical practice.

How much astigmatism to treat in cataract surgery.

PURPOSE OF REVIEW: Astigmatism correction in cataract surgery is a common surgical challenge. Although there are numerous approaches to its treatment during cataract surgery, there remains a lack of consensus on what level of postoperative astigmatism to target. We examine the literature to determine the effect of astigmatism on visual function and provide a recommendation on how much to treat in cataract surgery. RECENT FINDINGS: Distance visual acuity decreases as myopic, hyperopic, or mixed astigmatism increases. Near visual acuity decreases with hyperopic astigmatism but improves with myopic astigmatism. The effect of astigmatism is generally independent of axis; however, against-the-rule (ATR) astigmatism with mild myopia may benefit reading. A progressive ATR shift occurs with age whether or not an individual undergoes cataract surgery. In the presence of higher order aberrations, correction of astigmatism below 0.5 D shows minimal practical benefit. Presbyopia-correcting intraocular lenses (IOLs) are sensitive to astigmatism but achieve distance visual acuities similar to monofocal IOLs and reach their full near and/or intermediate potential when residual astigmatism 0.5 D or less. SUMMARY: In cataract surgery, we recommend correction to 0.5 D or less of postoperative residual astigmatism to achieve optimum visual function and patient satisfaction following cataract surgery.

Intraoperative blood loss and transfusion during primary pediatric liver transplantation: A single-center experience.

Children undergoing liver transplantation are at a significant risk for intraoperative hemorrhage and thrombotic complications, we aim to identify novel risk factors for massive intraoperative blood loss and transfusion in PLT recipients and describe its impact on graft survival and hospital LOS. We reviewed all primary PLTs performed at our institution between September 2007 and September 2016. Data are presented as n (%) or median (interquartile range). EBL was standardized by weight. Massive EBL and MT were defined as greater than the 85th percentile of the cohort. 250 transplantations were performed during the study period. 38 (15%) recipients had massive EBL, and LOS was 31.5 (15-58) days compared to 11 (7-21) days among those without massive EBL (P < 0.001). MT median LOS was 34 (14-59) days compared to 11 (7-21) days among those without MT (P = 0.001). Upon backward stepwise regression, technical variant graft, operative time, and transfusion of FFP, platelet, and/or cryoprecipitate were significant independent risk factors for massive EBL and MT, while admission from home was a protective factor. Recipient weight was a significant independent risk factor for MT alone. Massive EBL and MT were not statistically significant for overall graft survival. MT was, however, a significant risk factor for 30-day graft loss. PLT recipients with massive EBL or MT had significantly longer LOS and increased 30-day graft loss in patients who required MT. We identified longer operative time and technical variant graft were significant independent risk factors for massive EBL and MT, while being admitted from home was a protective factor.

Selective vulnerability of the intermediate retinal capillary plexus precedes retinal ganglion cell loss in ocular hypertension.

Introduction: Glaucoma, a disease of retinal ganglion cell (RGC) injury and potentially devastating vision loss, is associated with both ocular hypertension (OHT) and reduced ocular blood flow. However, the relationship between OHT and retinal capillary architecture is not well understood. In this project, we studied microvasculature damage in mice exposed to mild levels of induced OHT. Methods: Mild OHT was induced with the microbead model for 2 weeks. At this time point, some retinas were immunostained with CD31 (endothelium), Collagen IV (basement membrane), and RBPMS (RGCs) for z-stack confocal microscopy. We processed these confocal images to distinguish the three retinal capillary plexi (superficial, intermediate, and deep). We manually counted RGC density, analyzed vascular complexity, and identified topographical and spatial vascular features of the retinal capillaries using a combination of novel manual and automated workflows. Other retinas were dissociated and immunopanned to isolate RGCs and amacrine cells (ACs) for hypoxia gene array analysis. Results: RGC counts were normal but there was decreased overall retinal capillary complexity. This reduced complexity could be explained by abnormalities in the intermediate retinal capillary plexus (IRCP) that spared the other plexi. Capillary junction density, vessel length, and vascular area were all significantly reduced, and the number of acellular capillaries was dramatically increased. ACs, which share a neurovascular unit (NVU) with the IRCP, displayed a marked increase in the relative expression of many hypoxia-related genes compared to RGCs from the same preparations. Discussion: We have discovered a rapidly occurring, IRCP-specific, OHT-induced vascular phenotype that precedes RGC loss. AC/IRCP NVU dysfunction may be a mechanistic link for early vascular remodeling in glaucoma.

Is Organ Retransplantation Among Undocumented Immigrants in the United States Just?

Numerous undocumented children in the United States with end-stage renal disease undergo kidney transplantation funded by charitable donation or state-sponsored Medicaid. However, when these funding sources expire by adulthood, most are unable to pay for follow-up appointments and immunosuppressive medications necessary for maintenance of their organ. The organs fail and patients are then left with the options of retransplantation or a lifetime of dialysis. The dilemma of retransplantation introduces many questions regarding justice and fairness. This commentary addresses several ethical concerns about the special case of organ retransplantation for undocumented patients. Clinical guidelines and a clear public policy for best practices are needed to adequately address the challenge of retransplantation and maintenance immunosuppression in this population.

Reoperative complications following pediatric liver transplantation.

BACKGROUND: The aim of this study is to describe the incidence and impact of reoperation following pediatric liver transplantation, as well as the indications and risk factors for these complications. METHODS: All primary pediatric liver transplants performed at our institution between January 2012 and September 2016 were reviewed. A reoperative complication was defined as a complication requiring return to the operating room within 30 days or the same hospital admission as the transplant operation, excluding retransplantation. RESULTS: Among the 144 pediatric liver transplants performed during the study period, 9% of the recipients required reoperation. The most common indications for reoperation were bleeding and bowel complications. There was no significant difference in the graft survival of patients with a reoperation and those without a reoperation (p = 0.780), but patients with a reoperation had a significantly longer hospital length of stay (median of 39 days vs. 11 days, p = 0.001). Variant donor arterial anatomy, transplant operative time, intraoperative blood loss, transfusion volume of packed red blood cells or cell saver per weight, and transfusion with fresh frozen plasma, platelets, or cryoprecipitate were significantly associated with reoperation upon univariable logistic regression, but none of these risk factors remained statistically significant upon multivariable regression. CONCLUSION: At our institution, reoperation did not significantly impact graft survival. We identified variant donor arterial anatomy, transplant operative time, intraoperative blood loss, transfusion volume of packed red blood cells or cell saver per weight, and transfusion with fresh frozen plasma, platelets, or cryoprecipitate as risk factors for reoperation, although none of these risk factors demonstrated independent association with reoperation in a multivariable model. TYPE OF STUDY: Prognosis Study. LEVEL OF EVIDENCE: Level III.

Predicting Liver Allograft Discard: The Discard Risk Index.

BACKGROUND: An index that predicts liver allograft discard can effectively grade allografts and can be used to preferentially allocate marginal allografts to aggressive centers. The aim of this study is to devise an index to predict liver allograft discard using only risk factors available at the time of initial DonorNet offer. METHODS: Using univariate and multivariate analyses on a training set of 72 297 deceased donors, we identified independent risk factors for liver allograft discard. Multiple imputation was used to account for missing variables. RESULTS: We identified 15 factors as significant predictors of liver allograft discard; the most significant risk factors were: total bilirubin > 10 mg/dL (odds ratio [OR], 25.23; confidence interval [CI], 17.32-36.77), donation after circulatory death (OR, 14.13; CI, 13.30-15.01), and total bilirubin 5 to 10 mg/dL (OR, 7.57; 95% CI, 6.32-9.05). The resulting Discard Risk Index (DSRI) accurately predicted the risk of liver discard with a C statistic of 0.80. We internally validated the model with a validation set of 37 243 deceased donors and also achieved a 0.80 C statistic. At a DSRI at the 90th percentile, the discard rate was 50% (OR, 32.34; CI, 28.63-36.53), whereas at a DSRI at 10th percentile, only 3% of livers were discarded. CONCLUSIONS: The use of the DSRI can help predict liver allograft discard. The DSRI can be used to effectively grade allografts and preferentially allocate marginal allografts to aggressive centers to maximize the donor yield and expedite allocation.