Cheek‐Norgan, E. Heidi

Abstract Obstetric training programs typically offer limited formal education on placental pathology; yet, in practice, obstetric providers are expected to incorporate placental pathology findings into the overall evaluation of obstetric complications. In this narrative review, we briefly review pathology classifications and then delve deeper into pathology findings that may change clinical decision‐making, specifically highlighting pathologic lesions with a recurrence risk and recommended management for subsequent pregnancies. Last, we present specific recommendations on how to improve clinical interpretability and utility of placental pathology reports for obstetrical practice.

ObjectivesFetal growth restriction (FGR) is commonly associated with placental dysfunction, increasing perinatal morbidity and mortality. Visualizing placental vessels in utero would be advantageous for identifying functional FGR cause and determining proper management strategies. We aimed to utilize high‐sensitivity ultrasound microvessel imaging (HUMI) for quantifying placental vessel density (VD) in pregnancies diagnosed with FGR.MethodsThis pilot case–control study enrolled subjects in the third trimester with a diagnosis of FGR (n = 40) and gestational age‐matched controls with normal fetal growth (n = 20) at a 2:1 ratio, respectively. The Verasonics Vantage ultrasound system was used to perform HUMI on each participant at one timepoint. Scanning involved randomized singular value decomposition‐based clutter filtering to identify the villous tree, followed by step‐by‐step scanning to acquire 3‐dimensional‐like data. Mean VD was calculated from three ultrasound measurements per subject. Additional clinical and pathology data were also collected and compared.ResultsSixteen participants were utilized to establish the scanning protocol and 2 met exclusion criteria at delivery. Thus, VD was successfully measured on 42 pregnancies scanned at 35 weeks 5 days on average. In FGR (n = 24), placental VD was significantly reduced compared to controls (P < .01). VD measures were as good at predicting FGR as systolic/diastolic (S/D) ratios (area under the curve 0.86 versus 0.80). In a smaller cohort, VD in placentas with a diagnosis of inflammatory villitis (n = 10) by histology showed an increase in VD compared to those without inflammation (P = .01). Low VD was correlated with increased S/D ratios (P = .03).ConclusionsHUMI is useful for identifying altered placental vascularization in utero for FGR. VD may be a valuable indicator for placental health and could lead to improved risk stratification methods considering underlying biology.

Diseases of the carotid arteries can be classified into different categories based on their origin. Atherosclerotic carotid disease remains the most encountered arterial wall pathology. However, other less-common non-atherosclerotic diseases can have detrimental clinical consequences if not appropriately recognized. The underlying histological features of each disease process may result in imaging findings that possess features that are obvious of the disease. However, some carotid disease processes may have histological characteristics that manifest as non-specific radiologic findings. The purpose of this manuscript is to review various non-atherosclerotic causes of carotid artery disease as well as their histologic-radiologic characteristics to aid in the appropriate recognition of these less-commonly encountered pathologies.

Objective To evaluate maternal risk factors associated with chronic villitis of unknown etiology (VUE) and to describe cooccurring placental pathologies. Study Design A retrospective case–control study was conducted using placental pathology records from deliveries ≥ 20 weeks between 2010 and 2018. Cases were placentas with documented chronic villitis without infectious cause, hereafter called VUE. Controls were placentas without this diagnosis, matched to the cases 2:1. Maternal and neonatal demographic and clinical data were collected. Descriptive statistics are reported with Fisher's exact test or a chi-squared test, as appropriate, and multivariable conditional logistic regression was conducted. Results Our study included 352 cases with VUE and 657 controls. A diagnosis of gestational diabetes (p = 0.03) and gestational hypertension (p = 0.06) was 1.5 times more likely to occur in those with a VUE diagnosis. A trend was also seen for chronic hypertension (odds ratio [OR] = 1.7, p = 0.07) and preeclampsia (OR = 1.5, p = 0.09) compared with controls. Placentas with VUE, specifically high-grade VUE, were more likely to be small for gestational age (p = 0.01), and to be diagnosed with other placental findings including lymphoplasmacytic or chronic deciduitis (p < 0.01), maternal (p < 0.01) and fetal vascular malperfusion (p = 0.02), and chorionitis (acute or chronic; p < 0.01). Conclusion Gestational diabetes and hypertension were associated with a diagnosis of VUE, and overall, VUE placentas have more abnormal placental findings compared with control. Understanding VUE risk factors may facilitate prenatal care strategies and counseling to achieve the best outcomes for pregnant patients and their neonates. Key Points

Context.— Respiratory infections complicate lung transplantation and increase the risk of allograft dysfunction. Allograft lungs may have different susceptibilities to infection than native lungs, potentially leading to different disease severity in lungs of single lung transplant recipients (SLTRs). Objective.— To study whether infections affect allograft and native lungs differently in SLTRs but similarly in double LTRs (DLTRs). Design.— Using an institutional database of LTRs, medical records were searched, chest computed tomography studies were systematically reviewed, and histopathologic features were recorded per lung lobe and graded semiquantitatively. A multilobar-histopathology score (MLHS) including histopathologic data from each lung and a bilateral ratio (MLHSratio) comparing histopathologies between both lungs were calculated in SLTRs and compared to DLTRs. Results.— Six SLTRs died of infection involving the lungs. All allografts showed multifocal histopathologic evidence of infection, but at least 1 lobe of the native lung was uninvolved. In 4 of 5 DLTRs, histopathologic evidence of infection was seen in all lung lobes. On computed tomography, multifocal ground-glass and/or nodular opacities were found in a bilateral distribution in all DLTRs but in only 2 of 6 SLTRs. In SLTRs, the MLHSAllograft was higher than MLHSNative (P = .02). The MLHSratio values of SLTR and DLTR were significantly different (P &lt; .001). Conclusions.— Allograft and native lungs appear to harbor different susceptibilities to infections. The results are important for the management of LTRs.

AbstractObjectiveFetal surgery has improved neonatal outcomes; however, it is unknown if the intervention contributes to the developmental of inflammatory pathologies in the placenta. Here, an association between fetal surgery and placental pathology was examined.MethodThis case‐control study compared pregnancies with fetal surgery (n = 22), pregnancies with an indication for fetal surgery but without an intervention being done (n = 13), and gestational‐age and fetus‐number matched controls (n = 36). Data on maternal, infant, and placental outcomes were abstracted. Additionally, immunohistochemistry identified expression of lymphoid and myeloid cells in the placenta on a subset of cases. Comparisons were performed using Kruskal‐Wallis or Pearson's chi‐squared tests.ResultsMaternal characteristics were comparable between groups. Most fetal interventions were for diaphragmatic hernia, spina bifida, or twin‐to‐twin transfusion syndrome. Fetuses who were operated on before birth were more likely to be born preterm (p = 0.02). There was no increase in the rate of observed placental pathologies or immune cell infiltration in fetal surgery cases compared to controls.ConclusionThe data suggest that fetal surgery is not associated with increased inflammatory or morphologic pathology in the placenta. This observation supports the growing field of fetal surgery.