Clinical Analysis In Risk Factors And Outcomes For Retinopathy Of Prematurity

BackgroundRetinopathy of prematurity (ROP) is a multifactorial disease that occurs most frequently in very small and sick infants, and can potentially cause blindness in infants born prematurely. With the increasing survival of premature infants, a "third epidemic" is in the making. The incidence of ROP is different in accordance with the different criteria in different countries. The population of infants who develop severe ROP in highly developed countries differs from those in developing countries. The risk factors for the development of ROP and severe ROP include, as current research data show, low birth weight, low gestational age at birth, sepsis, intraventricular hemorrhage, exposure to light, prolonged mechanical ventilation, and multiple transfusions, but the precise roles these individual factors may play in the disease progression have not yet been determined. In most cases, spontaneous regression of ROP usually occurs without serious residual in eyes with stages1,2and early stage3while blindness or serious visual impairment results from progression to retinal detachment or severe distortion of the posterior retina. Although the early treatment of high-risk prethreshold ROP and threshold ROP can significantly reduce unfavorable outcomes in both primary and secondary (structural) measures, the patients who underwent vitrectomy either initially or at a later time have poor postoperative visual acuity even retinal redetachment and poor life-quality in the long run, besides the high care costs. Therefore, there is a need to develop diverse approaches which can prevent ROP blindness extending from policies and practices.Early detection and prompt treatment of ocular disorders in infants is important to avoid lifelong visual impairment. Examination of the eyes should be performed beginning in the newborn period and at all well-child visits. Furthermore, it is necessary to establish complete and effective ROP screening system, and strive to achieve early diagnosis and early treatment. Since the screening of ROP in China is still in the preliminary stage, the overall incidence, prevalence and progression of ROP have not been reported. Meanwhile, the studies in ROP are mainly focus on the prevention and treatment on the level of medical technology, instead of the perspective of epidemiology. In China, it is still lack of complete and systematic large sample long-term follow-up, especially lack of ROP and intervention in the natural course of evolution after treatment. Our research aims to take fundus examination in the preterm neonates to observe the common diseases and report the outcomes in a neonatal intensive care unit (NICU) in Guangzhou between May2008and May2011; To evaluate the incidence and risk factors for severe retinopathy of prematurity; To evaluate the possibilities and incidence of spontaneous regression of changes in the retina in active stage of retinopathy of prematurity and identify the possible relative factors during the regression.Chapter1Outcomes of957preterm neonatal fundus examinations in a Guangzhou NICU through2008to2011ObjectiveTo take fundus examination in the preterm neonates to observe the common diseases and report the outcomes in a neonatal intensive care unit (NICU) in Guangzhou between May2008and May2011.MethodsFundus examinations were performed with Retcam Ⅱ in957prematures at the NICU of Zhujiang Hospital of Southern Medical University, Guangzhou, China, between May2008and May2011. The screening sessions and the follow-up were performed according to Chinese guidelines to detect and treat retinopathy of prematurity(ROP), which recommended initial ophthalmological examination should be performed between the fourth and sixth weeks of life or from32weeks of postmenstrual age and should be repeated weekly or more frequently according to the findings until full vascularization of the peripheral retina is observed or until45weeks of postmenstrual age. On each examination, pupils’ dilation was done using0.5%tropicamide at least30minutes prior to examination. Topical proparacaine was applied and an eye speculum was inserted. Digital images were taken with the Retinal Camera Ⅱ (Massie Research Laboratories Inc.) using the130°ROP lens. Indirect ophthalmoscopy was performed using a28D lens and secleral depression in necessary.ResultsThere were957prematures in this study, including666males and291females,2triple births,152twins and803singletons. During the three years,86infants with any stage retinopathy of prematurity (ROP)(8.99%),123infants with retinal hemorrhage(12.85%),10infants with neonatal fundual jaundice(1.04%) and3babies with congenital choroidal coloboma(0.31%) were found. The incidence of these ocular diseases was significantly different between males and females except retinal hemorrhage(P=0.026).ConclusionEarly detection and prompt treatment of ocular disorders in neonates is important to avoid lifelong visual impairment. Examination of the eyes should be performed in the newborn period and at all well-child visits. RetCamⅡ is a crucial tool for the neonatal fundal examination, not only in the screening of ROP, but also used in screening of ocular disease. Chapter2Risk factors for severe retinopathy of prematurity in premature infantsObjectiveTo evaluate the incidence and characteristics between2008and2011in the NICU in Zhujiang Hospital in Southern Medical University; To analyze the risk factors for severe retinopathy of prematurity in preterm infants.MethodsBetween May,2008and May,2011, a total of957preterm infants at4-6weeks of chronological age or32weeks of postmenstrual age underwent retinal evaluation by RetCamⅡ in our center, and the data of infants with ROP in any stage were analyzed. For the purpose of this study, mild ROP was defined as stage1,2or3which did not evolve into type1prethreshold or threshold, and severe ROP as high-risk type1prethreshold and threshold, stages4and5. The perinatal variables considered for the study included gender, mode of delivery, single or multiple pregnancy, gestational age at birth, birth weight, weight gain from birth to the sixth week of life, duration of mechanical ventilation, total duration of oxygen inhalation, use of indomethacin, erythropoietin, dopamine and surfactant, blue light, need for and times of blood transfusion, neonatal jaundice,1,5,10-min Apgar scores, presence of septicemia, hyaline membrane disease (HMD), and patent ductus arteriosus (PDA). Duration of stay in the NICU was also recorded.ResultsAmong the957preterm infants, we found86(8.99%) infants to have ROP in different stages, including60(6.27%) with mild ROP and26(2.72%) with severe ROP. The incidence of ROP during2008and2009was16.60%, with mild ROP11.7%and severe ROP4.97%; The incidence of ROP during2009and2010was5.49%, with mild ROP3.05%and severe ROP2.44%; The incidence of ROP during2010and2011was6.37%, with mild ROP5.22%and severe ROP1.37%. Among the86infants with any stage ROP, the mean birth weight was1537.78±337.20g, the average postnatal weight gain in the first six weeks of life was729.77±216.31g and the average gestational age was31.28±2.45weeks. The mean birth weight, postnatal weight gain in the first6weeks and gestational age in the babies with severe ROP was1420.40±328.64g,706.00±201.74g and29.88±1.67weeks, as compared to1593.28±339.30g,739.04±221.38g and31.78±2.53weeks in infants with mild ROP, respectively. Significant differences were noted between the two groups in the mean birth weight and gestational age, but not the postnatal weight gain (.P=0.568). Univariate analysis identified gestational age (P=0.001), birth weight (P=0.035),1min Apgar score (P=0.001),5min Apgar score (P=0.005), number of blood transfusion (P=0.032), presence of apnea (P=0.04), and retinal hemorrhage (.P=0.000) as the significant variables for severe ROP. The other variables including gender, mode of delivery, multiple births, single birth, duration of mechanical ventilation, use of surfactant, indomethacin, erythropoietin, dopamine, blue light, neonatal jaundice, occurrence of PDA, HMD, or septicemia were not considered significant for the development of severe ROP (P>0.05). Of the7predictive factors, only gestational age and retinal hemorrhage remained in the logistic regression analysis as independent predictive factorsConclusionSevere ROP tends to have a decreasing incidence and occurs more often in more mature preterm infants. The affected infants have the characteristics of the first epidemics, which imply that the infants whose gestational age between28and32 weeks or birth weight between1100and1750g should be screened seriously and continuously. Gestational age and retinal hemorrhage are independent predictive factors for severe ROP; nevertheless, this does not exclude the presence of other potential risk factors when monitoring premature infants. Furthermore, timely retinal screening of high-risk premature infants is important to prevent the development of advanced ROP. Chapter3Clinical Analysis in Outcomes for Retinopathy of PrematurityObjectiveTo evaluate the incidence of spontaneous regression of changes in the retina and vitreous in active stage of retinopathy of prematurity and identify the possible relative factors during the regression.MethodsThis is a retrospective, hospital-based study. The sample (n=56)included all preterm infants who were diagnosed as any ROP stage and followed up at least45weeks of postmenstrual age or until the retinal fully vascularization or effective stabilization of retinopathy was achieved after treatment. Infants who died or who were lost to follow-up before regression of ROP or documentation of mature peripheral retinal vessels were excluded. If outpatient examinations were missed or delayed more than2weeks beyond the scheduled appointment and if the ROP was found to be regressed at the time of the delayed appointment, that patient was considered to be lost to follow-up and was excluded from the study. For the purpose of this study, completely spontaneous regression was defined as the disappearance of all active neovascularization of perfused neovascular shunt with normal vessels to outer zone III without any treatment. The56infants were divided into two groups according to the development of ROP. Group A (spontaneous regression ROP group) consisted of39patients who were diagnosed with stage1or2ROP but showed regression; Group B (treated ROP group) comprised17patients with which ROP progressed to stage3(high-risk prethreshold or threshold ROP, early treatment of ROP) or AP-ROP and received treatment. None of the infants in the study were diagnosed as stage4or5ROP. Data on gender, single or multiple pregnancy, gestational age, birth weight, weight gain from birth to the sixth week of life, use of oxygen in mechanical ventilation, total duration of oxygen inhalation, surfactant given or not, need for and times of blood transfusion,1,5,10-min Apgar score, presence of bacterial or fungal or combined infection, hyaline membrane disease (HMD), patent ductus arteriosus (PDA), duration of stay in the NICU and duration of ROP were recorded. Presence and incidence of spontaneous regression of ROP, duration of ROP, predictive factors for the spontaneous regression were the main outcome measures.ResultsIn group A, there were30babies with stage1ROP, of which26babies (86.67%) were observed spontaneous regression of changes in the retina and vitreous,2babies were detected to progress to stage2then involuted naturally and2were found to progress to severe stage for treatment. In stage2,12infants (54.17%) out of21patients including the2from stage1were found to naturally regress,9progressed to stage3in which only one regressed completely in stage3. While, in stage3, there was only one case (5.89%) from stage2spontaneously regressed in the following examinations, the rest12patients were treated. Similarly, there were33babies with any ROP in zone Ⅲ, which were completely regressed (100%). In zone Ⅱ, regression in6(46.15%) babies of13was detected. However, there was no case with natural involution in the three patients with ROP in zone I (0%), in which2babies developed acute posterior retinopathy of prematurity (APROP),1baby with threshold ROP need for treatment. The mean duration of ROP in spontaneous regression group was5.65±3.14weeks, lower than that of the treated ROP group (7.34±4.33weeks), but this difference was not statistically significant (P=0.201). After univariate analysis, the significant variables for spontaneous regression of ROP were gestational age (GA)(P=0.010),1min Apgar score (P=0.009),5min Apgar score (P=0.038), duration in NICU (P=0.020), oxygen therapy longer than10days (P=0.032) and presence of retinal hemorrhage (P=0.002). The average birth weight (BW) was1573.08±373.31g for group A and1375.88±314.17g for group B, which was not significantly different (P=0.063). Accordingly, the mean weight gain in the first six weeks of life was733.39±237.97g versus669.29±223.18g between group A and B, but this difference was also not statistically significant (P=0.392). The other variables gender, mode of delivery, multiple births, single birth, duration of mechanical ventilation, use of surfactant, indomethacin, erythropoietin, dopamine, blue light, neonatal jaundice, blood transfusion, occurrence of PDA, HMD, septicemia were not considered significant for the spontaneous regression of ROP (p>0.05). Of the seven predictive factors, only retinal hemorrhage remained in the logistic regression analysis as independent predictive factors.ConclusionsThis study shows most stage1and2ROP lesions can naturally regression without any treatment, while stage3and above are most in need of treatment, which can also find degenerative changes in the following screening after treatment in the end; Changes in zone Ⅲ can spontaneously regression, while zone Ⅱ, Ⅰ lesions must be closely observed, once found any severe changes, effective measures must be taken in time to avoid retinal detachment; Birth weight and the weight gain in the first six weeks after birth show no significant difference in the spontaneous regression between the two groups; Gestational age has certain relevant with the process of spontaneous regression, but can not be a dependent risk factor for predicting the natural regression; Retinal hemorrhage was weakly inversely associated with the spontaneous regression.