ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Conclusion: Cases with isolated clinical umbilical cord compro- mise were associated with the most unfavourable clinical outcome as umbilical cord complications and pathology strike unexpectedly and are notorious for unpredictability, causing stillbirths not asso- ciated with other maternal or foetal diseases. This finding paral- leled the histological segmental FVM most common in Groups 1 and 3, both with the umbilical cord aetiology. The clinical risks alone for FVM alone, without the umbilical cord factors (Group 2), were not associated with increased rate of FVM. OFP-08-006 Placental recent/on-going foetal vascular malperfusion with endothelial fragmentation is diagnostically equivalent to established distal villous lesions of foetal vascular malperfusion J. Stanek* *Cincinnati Children’s Hospital, USA Background & objectives: CD34 immunostaining increases sensitivity of placental diagnosis of foetal vascular malperfusion (FVM). This comparative retrospective study was performed to find out whether recent distal FVM lesions diagnosed with CD34 immu- nostaining are diagnostically equivalent to remote FVM lesions diagnosed with hematoxylin-eosin Methods: Clinical and placental phenotypes of 562 placentas from ≥20weeks high-risk pregnancies were analysed: Group 1 - 158 placentas with remote distal villous FVM (by H&E only), Group 2 - 142 placentas showing clustered endothelial fragmentation by CD34 immunostaining, 98 of them also with H&E distal FVM lesions (on-going, temporal heterogeneity), Group 3 - 262 placentas without distal villous FVM. Results: Foetal congenital malformations were seen in most cases of each group (58.5% of all cases). Using Bonferroni correction, there were no statistically significant differences in clinical or pla- cental phenotypes between Group 1 and Group 2, or among the 3 groups (p>0.002). However, in Group 1, gestational age was the shortest, postnatal mortality most frequent, placental weight the smallest, intra villous haemorrhage, erythroblasts in foetal blood, hypertrophic decidual arteriopathy, and foetal vascular thrombi most common, and in Group 2, placental infarction, post-uterine pattern of chronic placental injury and excessive extra villous trophoblasts of chorionic disc were most common (p<0.05). Conclusion: In this cohort of foetuses/neonates dominated by con- genital malformations, distal villous FVM was the most common pattern of placental injury. The absence of statistically significant differences in clinical or placental phenotypes among all 3 groups indicates that distal villous FVM diagnosed by CD34 and that diag- nosed by H&E are diagnostically/prognostically equivalent. CD34 immunostaining is therefore a powerful tool in diagnosis of distal villous FVM. OFP-08-007 Cardiac arrest with successful cardiopulmonary resuscitation induces histologic changes that correlate with survival time and lead to misdiagnosis in sudden arrhythmic death syndrome J. Coelho Lima*, J. Westaby, M. Sheppard *Department of Pathology, University of Cambridge, United Kingdom Background & objectives: Sudden arrhythmic death syndrome (SADS) is defined as sudden cardiac death (SCD) with a morpho- logically normal heart. Cardiac arrest with cardiopulmonary resus- citation (CPR) may induce cardiac histologic changes. We aimed to assess whether such changes could confound SADS diagnosis. Methods: Retrospective observational study analysing all consecu- tive cases of sudden death prospectively referred to a UK national cardiac pathology centre between January 2017 and November 2021. Cases showing hypoperfusion features due to cardiac arrest followed by CPR were identified after review of clinical informa- tion and examination by two expert cardiac pathologists. Data is presented as percentage or median. Results: Out of 2,568 SCD cases, 126 (4.9%) were identified with hypoperfusion changes. Macroscopically, the commonest find- ing was left ventricular focal or diffuse subendocardial haemor- rhage (13.5%). Microscopically, haemorrhage and contraction band necrosis (n=50, 37.7%), subendocardial acute infarction (n=44, 34.1%), interstitial mixed inflammatory cell infiltrates (n=31, 24.9%), granulation tissue (n=9, 7.1%) and subendocardial fibrosis (n=1, 0.7%) were observed. These changes correlated to duration of survival following resuscitation, with subendocardial infarction and granulation tissue being observed later at 2 and 9.5 days, respectively (p<0.001). In a subcohort of 41 cases, autopsy pathologists misinterpreted such changes as ischaemic myocardial infarction (n=7; 17%), myocarditis (n=5; 12.1%), or other patholo- gies (n=2; 4.8%) in 14 SADS cases. Conclusion: We provide a comprehensive characterisation of hypoperfusion-related changes in the heart following successful CPR with survival, which are time related. These features can lead to diagnostic confusion among pathologists but knowledge of history of resuscitation with survival should help with general and expert pathology assessment and improve SADS diagnostic yield, prompting genetic screening of decedents’ relatives. Funding: Cardiac Risk in the Young Grant numbers: 12840-14 OFP-08-008 Post-mortem pulmonary findings in a large series of COVID-19 cases at the University of Texas Medical Branch (2020-2022): insights from an ancient and still relevant procedure J.P. Olano*, I. Marin, J. Estrada *University of Texas Medical Branch, USA Background & objectives: COVID-19 is an infection due to SARS-CoV-2 and was declared by WHO a pandemic on March 11, 2020. This project addresses the spectrum of pulmonary pathology in 294 autopsy cases performed at a single tertiary care institution. Methods: A total of 294 autopsies were performed in our service between April 2020-2022. All cases were diagnosed by nucleic acid amplification (real-time RT-PCR) using post-mortem nasal swabs. Demographics, clinical history, gross and histologic findings were collected prospectively. Histologic sections were routinely stained with H&E, Masson’s Trichrome and MOVAT pentachrome. Other special stains were performed as needed (PAS-D, MSB, etc). Results: The average age was 60 years (range: 28-94). Clinical spectrum ranged from asymptomatic infections (cause of death unrelated to COVID-19) to lethal outcome. Clinical course was 2-120 days with an average of 19. The main risk factors included systemic hypertension, morbid obesity, diabetes mellitus, coro- nary artery disease, congestive heart failure, emphysema, cir- rhosis and chronic renal disease. The main complications were hepatic encephalopathy, thrombotic microangiopathy, acute kidney injury (AKI) and bacterial bronchopneumonia. Virtually all lungs showed markedly increase weight and consolidation. Histologic findings included interstitial pneumonitis, oedema, hyaline membranes, acute fibrinous organizing pneumonia, type 2 pneumocyte hyperplasia, reactive/atypical type 2 pneumocytes, fibroblastic foci in alveolar spaces, fibrosis, squamous and bron- chiolar metaplasia. Conclusion: Virtually all patients had at least one risk factor, the most common being systemic hypertension. Numerous patients had two or more risk factors. The spectrum of histologic findings in the S33