Effect of red blood cell transfusion on the development of retinopathy of prematurity: A systematic review and meta-analysis

Hyperferritinemia among very-low-birthweight infants in Thailand: a prospective cohort study

OBJECTIVES

To determine the incidence of hyperferritinemia in VLBW infants, and its association with neonatal morbidity.

STUDY DESIGN

Prospective cohort study in a tertiary-level hospital in Bangkok, from March 2022 to January 2023. Serum ferritin (SF) was measured in VLBW infants at one month and repeated monthly for those with hyperferritinemia (SF > 300 ng/mL).

RESULTS

Gestational age and birth weight were 29.7 ± 2.4 weeks (mean ± SD) and 1100 g (IQR, 830, 1340). Hyperferritinemia was identified in 30.1% (95% CI, 20.8-41.4). After adjustment, only packed red cell transfusion >15 mL/kg was associated with hyperferritinemia (RR 3.1; 95% CI, 1.5-6.4). All elevated SF levels returned to normal within four months. Hyperferritinemia was associated with severe bronchopulmonary dysplasia (RR 2.3, 95% CI, 1.0-5.4) and retinopathy of prematurity (RR 3.5, 95% CI, 1.4-8.6).

CONCLUSION

Hyperferritinemia is common among our VLBW infants, particularly after transfusion, and is associated with severe BPD and ROP.

Transient activation of retinopathy of prematurity secondary to erythrocyte suspension transfusion

Retinopathy of prematurity (ROP) is a serious retinal vascular disorder that needs prompt diagnosis, and treatment to prevent undesired visual outcomes. Due to its shorter period of disease progression, it is important to be hasty in treating ROP. Erythrocyte suspension (ES) aggravates the progression of ROP. However, this progression may be transient as in the present case reports. This case report aimed to present two cases that developed type 1 ROP after erythrocyte suspension transfusion. Clinical findings of the patients were resolved within a few days without any intervention. Premature infants receiving ES treatment can be observed for 24-48 hours, and the treatment can be planned after determining the persistence of the plus sign. Abbreviations: ES = Erythrocyte suspension, ROP = Retinopathy of prematurity, NICU = neonatal intensive care unit.

Retinopathy of Prematurity and Glucose-6-Phosphate Dehydrogenase Activity: A Case-Control Study

OBJECTIVE

To determine whether red blood cell glucose-6-phosphate dehydrogenase (G6PD) activity is associated with retinopathy of prematurity (ROP).

METHODS

This case-control study was conducted in a Level-3 neonatal unit. Subjects were inborn boys with birth weight <2000 g. "Cases" were consecutive subjects with ROP of any severity. "Controls" were consecutive unrelated subjects without ROP. Recipients of blood or exchange transfusions were excluded. Sixty cases (out of 98 screened) and 60 controls (out of 93 screened) were enrolled. G6PD activity (quantitative assay) as the candidate risk factor was evaluated.

RESULTS

Sixty cases with 60 controls [mean (SD) gestation 28.80 (2.2) and 30.60 (2.2) wk respectively] were compared. "Cases" had a higher median (1st, 3rd quartile) G6PD activity compared to "controls" [7.39 (4.7, 11.5) vs. 6.28 (4.2, 8.8) U/g Hb, p = 0.084]. G6PD activity was highest among ROP requiring treatment [8.68 (4.7, 12.3)] followed by ROP not requiring treatment [6.91 (4.4, 11.0)], followed by controls (plinear trend = 0.06). Gestation, birth weight, duration of oxygen, breastmilk feeding, and clinical sepsis were other variables associated with ROP on univariable analysis. On multivariable logistic regression, G6PD activity [Adjusted OR 1.14 (1.03, 1.25), p = 0.01] and gestation [Adjusted OR 0.74 (0.56, 0.97), p = 0.03] independently predicted ROP. C-statistic of the model was 0.76 (95% CI 0.67, 0.85).

CONCLUSIONS

Higher G6PD activity was independently associated with ROP after adjusting for confounders. Each 1 U/g Hb increase in G6PD increased the odds of ROP by 14%. Severer forms of ROP were associated with higher levels of G6PD activity.

Hematologic Risk Factors for the Development of Retinopathy of Prematurity—A Retrospective Study

(1) Background: Retinopathy of prematurity (ROP) can cause severe visual impairment or even blindness. We aimed to assess the hematological risk factors that are associated with different stages of ROP in a cohort of preterm newborns, and to compare the clinical characteristics and therapeutic interventions between groups. (2) Methods: This retrospective study included 149 preterm newborns from a tertiary maternity hospital in Romania between January 2018 and December 2018, who were segregated into: Group 1 (with ROP, n = 59 patients), and Group 2 (without ROP, n = 90 patients). The patients that were affected by ROP were subsequently divided into the following subgroups: Subgroup 1 (Stage 1, n = 21), Subgroup 2 (Stage 2, n = 35), and Subgroup 3 (Stage 3, n = 25). The associations were analyzed using multivariate logistic regression and sensitivity analysis. (3) Results: Platelet mass indexes (PMI) that were determined in the first, seventh, and tenth days of life were significantly associated with Stage 1 ROP. PMI determined in the first day of life was also significantly associated with Stage 2 ROP. The sensitivity and specificity of these parameters were modest, ranging from 44 to 57%, and 59 to 63%. (4) Conclusions: PMI has a modest ability to predict the development of ROP.

Systemic Cytokines in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), a vasoproliferative vitreoretinal disorder, is the leading cause of childhood blindness worldwide. Although angiogenic pathways have been the main focus, cytokine-mediated inflammation is also involved in ROP etiology. Herein, we illustrate the characteristics and actions of all cytokines involved in ROP pathogenesis. The two-phase (vaso-obliteration followed by vasoproliferation) theory outlines the evaluation of cytokines in a time-dependent manner. Levels of cytokines may even differ between the blood and the vitreous. Data from animal models of oxygen-induced retinopathy are also valuable. Although conventional cryotherapy and laser photocoagulation are well established and anti-vascular endothelial growth factor agents are available, less destructive novel therapeutics that can precisely target the signaling pathways are required. Linking the cytokines involved in ROP to other maternal and neonatal diseases and conditions provides insights into the management of ROP. Suppressing disordered retinal angiogenesis via the modulation of hypoxia-inducible factor, supplementation of insulin-like growth factor (IGF)-1/IGF-binding protein 3 complex, erythropoietin, and its derivatives, polyunsaturated fatty acids, and inhibition of secretogranin III have attracted the attention of researchers. Recently, gut microbiota modulation, non-coding RNAs, and gene therapies have shown promise in regulating ROP. These emerging therapeutics can be used to treat preterm infants with ROP.

Comparative efficacy and safety of restrictive versus liberal transfusion thresholds in anemic preterm infants: a meta-analysis of 12 randomized controlled trials

The comparative efficacy and safety of restrictive with liberal transfusion thresholds remain controversial in anemic preterm infants. This meta-analysis aimed to compare the efficacy and safety of these two transfusion thresholds for anemic preterm infants. We searched PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI) for relevant randomized controlled trials (RCTs) comparing restrictive with liberal transfusion thresholds in anemic preterm infants through April 30, 2022. Two independent investigators screened literature, extracted data, and appraised the methodological quality of eligible studies. Meta-analysis was conducted using RevMan version 5.3.5. Twelve RCTs with 4380 preterm infants were included. Liberal transfusion threshold significantly increased the level of hemoglobin after transfusion (mean difference (MD): -10.03; 95% confidence interval (CI): -15.98 to -4.08; p=0.001; I²=94%) and hematocrit (MD: -3.62; 95%CI: -6.78 to -0.46; p=0.02; I²=80%) compared with restrictive transfusion. Infants' age at first transfusion in restrictive transfusion group was higher than that of infants in liberal transfusion group (MD: 5.08; 95%CI: 2.27 to7.89; p=0.004; I²=54%); however, restrictive transfusion was associated with more time on supplemental oxygen (MD: 3.56; 95%CI: 1.93 to 5.18; p<0.001; I²=62%) and ventilator or CPAP (MD: 3.31; 95%CI: 1.42 to 5.20; p=0.006; I²=75%). For the remaining outcomes, two transfusion strategies were comparable. Furthermore, a series of sensitivity analyses confirmed the robustness of the level of hemoglobin after transfusion, age at first transfusion, time on ventilator or CPAP, and safety outcomes. Evidence with substantial heterogeneity indicates that liberal and restrictive transfusion thresholds are effective and safe blood cell transfusion strategies in anemic preterm infants, but the liberal strategy may be more effective in shortening the length of necessary respiratory support.

Latest Trends in Retinopathy of Prematurity: Research on Risk Factors, Diagnostic Methods and Therapies

Retinopathy of prematurity (ROP) is a vasoproliferative disorder with an imminent risk of blindness, in cases where early diagnosis and treatment are not performed. The doctors' constant motivation to give these fragile beings a chance at life with optimal visual acuity has never stopped, since Terry first described this condition. Thus, throughout time, several specific advancements have been made in the management of ROP. Apart from the most known risk factors, this narrative review brings to light the latest research about new potential risk factors, such as: proteinuria, insulin-like growth factor 1 (IGF-1) and blood transfusions. Digital imaging has revolutionized the management of retinal pathologies, and it is more and more used in identifying and staging ROP, particularly in the disadvantaged regions by the means of telescreening. Moreover, optical coherence tomography (OCT) and automated diagnostic tools based on deep learning offer new perspectives on the ROP diagnosis. The new therapeutical trend based on the use of anti-VEGF agents is increasingly used in the treatment of ROP patients, and recent research sustains the theory according to which these agents do not interfere with the neurodevelopment of premature babies.

Decreased Levels of Erythrocyte Membrane Arachidonic and Docosahexaenoic Acids Are Associated With Retinopathy of Prematurity

Purpose

Retinopathy of prematurity (ROP) can lead to blindness. Arachidonic acid (ARA) and docosahexaenoic acid (DHA) regulate retinal inflammation and angiogenesis. The aim of this study was to investigate red blood cell membrane (RBCM) ARA and DHA in preterm infants.

Methods

This prospective observational study divided infants into groups by ROP severity and RBCM ARA and DHA means and terciles.

Results

Although the mean ± SD RBCM ARA was different between groups (no ROP, 17.9% ± 0.7%, vs. type 2 ROP, 17.4% ± 0.8%, vs. type 1 ROP, 16.7% ± 1.0%; P < 0.001), the mean RBCM DHA was similar (P = 0.161). Infants with type 1 ROP were more likely to be in the lowest ARA and DHA terciles than in the highest (ARA, 44% vs. 5.6%; DHA, 22% vs. 5.6%). ARA and DHA declined over the first month of life in all ROP groups. At week 1, ARA was lower in the type 1 and type 2 ROP groups compared with the no-ROP group (18% ± 2% and 19% ± 3% vs. 21% ± 2%, respectively; P < 0.05 for all). At week 2, DHA and ARA were lower in the type I ROP group compared with the no-ROP group (3% ± 1% vs. 4% ± 1%, P = 0.03 and 16% ± 1% vs. 19% ± 1%, respectively; P < 0.01). A RBCM ARA% ≥ 17 was associated with a 45% reduction in any ROP. As the estimated 4-week ARA% mean increased by 1%, the odds of ROP decreased by 70% (odds ratio = 0.30; 95% confidence interval, 0.1-0.7).

Conclusions

Infants with severe ROP have lower ARA and DHA levels than infants without ROP. ARA and DHA may act synergistically to protect against ROP.

Effect of Small Volume Blood Sampling on the Outcomes of Very Low Birth Weight Preterm Infants

Very low birth weight (VLBW) preterm infants universally experience anemia of prematurity (AOP) while growing up. The effects of reduced blood sample volume on AOP, packed red blood cell (PRBC) transfusion, and outcome in VLBW preterm infants were examined in this study. To reduce blood loss due to phlebotomy, we set up a small volume blood sampling procedure in VLBW infants. In this retrospective study, we compared the VLBW infants who had undergone standard blood sampling (control group, n = 20) with those who underwent small volume blood sampling (study group, n = 84), with both groups receiving PRBC transfusion under restrictive criteria. Blood loss from phlebotomy and PRBC transfusion volume over 30 days was significantly lower in the study group than in the control group. Compared to the control group, hematocrit, reticulocyte, and iron levels were significantly higher in the study group. There were no significant differences in the proportion of patent ductus arteriosus, severe intraventricular hemorrhage, retinopathy of prematurity, and bronchopulmonary dysplasia between the two groups. The small volume blood sampling resulted in lower PRBC transfusion volume, less severe anemia, and greater bone marrow function at 30 days of age. This strategy can reduce potential adverse effects of PRBC transfusion in VLBW preterm infants.

Neurosensory Alterations in Retinopathy of Prematurity: A Window to Neurological Impairments Associated to Preterm Birth

Retinopathy of prematurity (ROP) is one of the main blinding diseases affecting preterm newborns and is classically considered a vascular disorder. The premature exposure to the extrauterine environment, which is hyperoxic in respect to the intrauterine environment, triggers a cascade of events leading to retinal ischemia which, in turn, makes the retina hypoxic thus setting off angiogenic processes. However, many children with a history of ROP show persistent vision impairment, and there is evidence of an association between ROP and neurosensory disabilities. This is not surprising given the strict relationship between neuronal function and an adequate blood supply. In the present work, we revised literature data evidencing to what extent ROP can be considered a neurodegenerative disease, also taking advantage from data obtained in preclinical models of ROP. The involvement of different retinal cell populations in triggering the neuronal damage in ROP was described along with the neurological outcomes associated to ROP. The situation of ROP in Italy was assessed as well.

Transfusion-Free Survival Predicts Severe Retinopathy in Preterm Neonates

Repeated red blood cell (RBC) transfusions are thought to increase the risk for retinopathy of prematurity (ROP), likely due to a critical fetal hemoglobin (HbF) reduction. In this study, we investigated if the postmenstrual age (PMA) of neonates at transfusion influences the risk for ROP. We estimated the cumulative transfusion-free survival (TFS) in a series of 100 preterm neonates receiving one or more RBC units. TFS was calculated by censoring patients at first transfusion and expressing the time between birth and transfusion as either PMA or postnatal day. Then, we investigated if TFS predicted the occurrence of severe ROP, defined as ROP stage 3 or higher. We found that neonates with severe ROP displayed a significantly shorter TFS expressed according to their PMA (p = 0.001), with similar TFS according to postnatal days. At receiver operating characteristic (ROC) curve analysis, receiving an RBC unit before week 28 of PMA predicted severe ROP with a sensitivity of 64% and a specificity of 78%. In addition, receiving a second RBC unit before the PMA of 29 weeks predicted severe ROP with a sensitivity of 75% and a specificity of 69%. At multivariate analysis, PMA at the second transfusion was even more informative than at first transfusion and outperformed all other variables in predicting severe ROP, with an odds ratio of 4.554 (95% CI 1.332-15.573, p = 0.016). Since HbF decrease is greater after multiple RBC transfusions, it is conceivable that neonates receiving more than one unit before the PMA of 29 weeks may be exposed to a greater disturbance of retinal vascularization. Any strategy aimed at preventing the critical HbF decrease at this low age might potentially reduce the risk for severe ROP.

Association of Blood Donor Sex and Age With Outcomes in Very Low-Birth-Weight Infants Receiving Blood Transfusion

IMPORTANCE

There are conflicting data on the association between blood donor characteristics and outcomes among patients receiving transfusions.

OBJECTIVE

To evaluate the association of blood donor sex and age with mortality or serious morbidity in very low-birth-weight (VLBW) infants receiving blood transfusions.

DESIGN, SETTING, AND PARTICIPANTS

This is a cohort study using data collected from 3 hospitals in Atlanta, Georgia. VLBW infants (≤1500 g) who received red blood cell (RBC) transfusion from exclusively male or female donors were enrolled from January 2010 to February 2014. Infants received follow-up until 90 days, hospital discharge, transfer to a non-study-affiliated hospital, or death. Data analysis was performed from July 2019 to December 2020.

EXPOSURES

Donor sex and mean donor age.

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite outcome of death, necrotizing enterocolitis (Bell stage II or higher), retinopathy of prematurity (stage III or higher), or moderate-to-severe bronchopulmonary dysplasia. Modified Poisson regression, with consideration of covariate interactions, was used to estimate the association between donor sex and age with the primary outcome, with adjustment for the total number of transfusions and birth weight.

RESULTS

In total, 181 infants were evaluated, with a mean (SD) birth weight of 919 (253) g and mean (SD) gestational age of 27.0 (2.2) weeks; 56 infants (31%) received RBC transfusion from exclusively female donors. The mean (SD) donor age was 46.6 (13.7) years. The primary outcome incidence was 21% (12 of 56 infants) among infants receiving RBCs from exclusively female donors, compared with 45% (56 of 125 infants) among those receiving RBCs from exclusively male donors. Significant interactions were detected between female donor and donor age (P for interaction = .005) and between female donor and number of transfusions (P for interaction < .001). For the typical infant, who received a median (interquartile range) of 2 (1-3) transfusions, RBC transfusion from exclusively female donors, compared with male donors, was associated with a lower risk of the primary outcome (relative risk, 0.29; 95% CI, 0.16-0.54). The protective association between RBC transfusions from female donors, compared with male donors, and the primary outcome increased as the donor age increased, but decreased as the number of transfusions increased.

CONCLUSIONS AND RELEVANCE

These findings suggest that RBC transfusion from female donors, particularly older female donors, is associated with a lower risk of death or serious morbidity in VLBW infants receiving transfusion. Larger studies confirming these findings and examining potential mechanisms are warranted.

Restrictive versus liberal transfusion thresholds in very low birth weight infants: A systematic review with meta-analysis

BACKGROUND

To assess the efficacy and safety of restrictive versus liberal red blood cell transfusion thresholds in very low birth weight infants.

METHODS

We searched MEDLINE, EMBASE, and Cochrane database without any language restrictions. The last search was conducted in August 15, 2020. All randomized controlled trials comparing the use of restrictive versus liberal red blood cell transfusion thresholds in very low birth weight (VLBW) infants were selected. Pooled risk ratio (RR) for dichotomous variable with 95% confidence intervals were assessed by a random-effects model. The primary outcome was all-cause mortality.

RESULTS

Overall, this meta-analysis included 6 randomized controlled trials comprising 3,483 participants. Restrictive transfusion does not increase the risk of all-cause mortality (RR, 0.99; 95% CI, 0.84 to 1.17; I2 = 0%; high-quality evidence), and does not increase the composite outcome of death or neurodevelopmental impairment (RR, 1.01, 95% CI, 0.93-1.09; I2 = 7%; high-quality evidence) or other serious adverse events. Results were similar in subgroup analyses of all-cause mortality by weight of infants, gestational age, male infants, and transfusion volume.

CONCLUSIONS

In very low birth weight infants, a restrictive threshold for red blood cell transfusion was not associated with increased risk of all-cause mortality, in either short term or long term.

Haemoglobin Levels in Early Life among Infants with and without Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disorder attributed to an ischaemic stimulus in preterm infants. Haemoglobin, the main component for oxygen transportation, may be implicated in ROP development. This retrospective study compared the mean weekly haemoglobin levels between infants with and without ROP over the first six weeks of life. Premature infants of less than 32 weeks gestational age and less than 1.5 kg birth weight were grouped into age and birth weight-matched ROP cases and controls. Weekly mean haemoglobin levels were documented. An independent t-test was used to analyze the difference in mean haemoglobin levels between infants with ROP and infants without ROP. Adjustment for confounders was performed using one-way analysis of covariance. There was a statistically significant difference in adjusted mean haemoglobin levels between the ROP and non-ROP group during the first week of life (p = 0.038). No significant intergroup differences were observed at the other weeks. Haemoglobin monitoring during the first week of postnatal life may be useful to guide ROP screening in premature infants.

Comparison of Mean Platelet Counts in Preterm Infants with and without Retinopathy of Prematurity

Platelets are a primary source of pro- and anti-angiogenic cytokines. However, the evidence of their role in retinopathy of prematurity (ROP) is controversial. This retrospective study aimed to compare mean weekly platelet counts between infants with and without ROP over the first 6 weeks of life. A total of 93 infants matched by gestational age and birth weight were recruited (31 with ROP, 62 without ROP). Weekly mean platelet counts and other related risk factors were documented. The repeated measure analysis of variance (ANOVA) and the repeated measure analysis of covariance (ANCOVA) were used to compare mean platelet counts over time between the two groups, with and without adjusting for confounders. We found significant differences in the weekly mean platelet counts of infants with and without ROP over the first 6 weeks of life (p = 0.002). These differences disappeared after adjusting for covariates (p = 0.489). Lower mean platelet counts in ROP infants are not directly related to ROP, but rather to the presence of other risk factors for ROP, such as culture-proven sepsis, blood transfusion and bronchopulmonary dysplasia.

Preventing adverse reactions in pediatric transfusions using washed platelet concentrate

Blood transfusion is an important form of supportive care in children; however, transfusion-associated adverse reactions (TARs) are a problem. As with adults, allergic transfusion reactions (ATRs) and febrile non-hemolytic transfusion reactions (FNHTRs) are major TARs, and the frequency of ATRs caused by platelet concentrate (PC) tends to be particularly high. The plasma component of the blood product is thought to be a major factor in the onset of TARs such as ATR and FNHTR. By contrast, in children, age, underlying disease, and number of blood transfusions may be relevant patient-related factors. Although acetaminophen or diphenhydramine may be used prophylactically to prevent TARs, there is no clear evidence of their effectiveness. Volume-reduced PC is used to prevent TARs; however, it may be difficult to maintain the quality of platelets. Plasma-replaced PC stored with platelet additive solution raises the concern that TARs cannot be completely prevented by residual plasma. Washed PC removes most of the plasma, so it can effectively prevent ATR and FNHTR. The recent development of platelet additive solution [M-sol, bicarbonate Ringer's solution supplemented with acid-citrate-dextrose formula A (BRS-A)] in Japan has enabled the maintenance of the quality of platelets for long periods. The clinical use of washed PC in Japan has therefore progressed. Washed PC with M-sol or BRS-A for pediatric patients can effectively prevent TARs without diminishing the transfusion effect. The supply of washed PC has begun from the Japanese Red Cross Society, and it has become possible to use washed PC at all medical institutions in Japan.

Incidence, Risk Factors and Screening Evaluation of Retinopathy of Prematurity in High Birthweight Infants: A Large Cohort Study in Turkey

Purpose: To report and evaluate the incidence and risk factors of retinopathy of prematurity (ROP) and to assess the sensitivity and specificity of Turkish national screening guideline (NSG) in heavier infants with a birth weight (BW) of >1500 g.Methods: The data of 1784 preterm infants with BW>1500 g, who were screened between 2009 and 2016 in a university hospital in Turkey, were analyzed retrospectively. The rates of any stage and severe (treatment-requiring) ROP incidence were investigated. The possible protective and risk factors were evaluated with univariate analyses and logistic regression analysis.Results: The rate of any stage ROP was 14.1% (n = 251). Severe ROP was observed in 11 infants (0.6%), and 2 of the infants (0.1%) had a gestational age (GA)>32 weeks, which fell outside of the NSG. In logistic regression analysis, BW, GA, O₂ therapy duration, and exchange transfusion were determined to be independent risk factors (respectively, p < .001, p < .001, P = .055, and P = .033). Furthermore, antenatal steroid therapy was determined to have a highly significant protective effect on ROP development (p < .001). The sensitivity of Turkish NSG in identifying severe ROP increased from 82% to 100% with the inclusion of risk factors in addition to GA and BW.Conclusion: This study shows the presence of severe ROP in mature and heavy infants in Turkey. The positive effect of antenatal steroid use and the negative impact of exchange transfusion have been demonstrated for ROP development in mature infants. Possible risk factors should be evaluated with GA and BW to avoid missing severe ROP.