Bois, Melanie C.

8549 Background: First-line treatment of early stage non-small cell lung cancer (NSCLC) is surgical resection, but with a 5-year survival of only 54%, rates of future relapse are high. Identifying patients at high risk of relapse can help guide adjuvant treatment decisions. Deep convolutional neural network (DCNN) AI models trained on tumor histology have shown incredible flexibility as potential biomarkers, both in lung cancer and more generally across many malignancies. While DCNN models can obtain extremely accurate results when used for routine purposes such as diagnosis, subtyping, and grading of malignancies, most models trained for prognostication or treatment response prediction do not reach performance sufficient for clinical application. Uncertainty quantification (UQ) – a family of techniques that give DCNN models the ability to report confidence alongside predictions – is an underexplored avenue in cancer AI that may help further improve performance and clinical application of models designed to provide clinicians with estimations of risk. Methods: To explore the potential use of UQ in clinically-oriented DCNN models, we trained models on a single-institution, retrospective digital tumor histology slide cohort from patients with Stage I-III NSCLC who underwent surgical resection to predict risk of future relapse. Estimation of uncertainty was performed using dropout as a Bayesian approximation, and uncertainty thresholds were calculated from training sets using a novel method to identify and remove low-confidence predictions. For comparison, a separate multivariate logistic regression was trained in cross-validation using known clinical risk factors. Results: We trained DCNN models on slides from 198 patients (40 relapsed, 158 without relapse). In this cohort, 130 patients had stage I disease (65.6%), 42 had stage II (21.2%), and 26 had stage III (13.2%). The average age was 69 years, 85% were current or previous smokers, and 38 received guideline-concordant adjuvant chemotherapy. Without UQ, a DCNN model predicted risk of future relapse with an average area under receiver operator curve (AUROC) of 0.74 across three-fold cross-validation. Using UQ estimation, 63% of slides were reported with high confidence. Relapse prediction was significantly improved in the high-confidence cohort, with an average AUROC of 0.83 in cross-validation. With a specificity of 70%, this corresponds to an average sensitivity of 86.8% across the three cross-folds (79.1%, 85.5%, and 95.7%). In comparison, a clinical-only multivariate regression model predicted relapse with a cross-validated AUROC of 0.67. Conclusions: This method of uncertainty quantification appears to be a powerful tool to predict lung cancer recurrence risk from digital histopathology while simultaneously providing clinicians with a measurement of algorithm trustworthiness.

Abstract Cardiac hemangioma is a rare, benign primary tumor characterized by endothelial proliferation. While reports of cardiac hemangiomas demonstrating 18 F FDG avidity and other forms of hemangiomas showing 68 Ga Dotatate avidity have been published, we present a rare case of primary cardiac hemangioma demonstrating 68 Ga Dotatate avidity, mimicking a primary neuroendocrine tumor.

Abstract Background Management of pulmonary hypertension (PH) in the setting of heart failure with preserved ejection fraction (HFpEF) can be challenging. Herein, we describe the case of a patient with HFpEF and combined pre- and post-capillary PH who showed striking improvement with sildenafil. Case summary A 74-year-old man presented with exertional dyspnea and near-syncope. He underwent a hemodynamic exercise study that showed evidence of HFpEF with pre- and post-capillary PH. Right ventricular endomyocardial biopsy showed interstitial fibrosis and mild hypertrophy, with no evidence of infiltrative or storage diseases. The patient was treated with sildenafil 20 mg three times daily, which resulted in significant symptomatic and functional improvement in 12 years of follow-up. Discussion Phosphodiesterase 5 inhibitors are currently not approved by the United States Food and Drug Administration for treatment of PH in heart failure and are used off-label in patients with heart failure. This case illustrates the importance of unloading the right ventricle to improve cardiac output in patients with diastolic dysfunction and combined pre- and post-capillary PH. Although promising, future studies are needed to validate these findings.

Context.— Studies of lungs in patients with COVID-19 have focused on early findings. Objective.— To systematically study histopathologic and imaging features and presence of SARS-CoV-2 RNA in lung tissue from patients in later stages of COVID-19. Design.— Autopsies, explants, surgical lung biopsies, transbronchial biopsies, cryobiopsies, and needle biopsies from patients with COVID-19 whose onset of symptoms/confirmed diagnosis was more than 28 days before the procedure were studied. Available images were reviewed. Reverse transcription droplet digital polymerase chain reaction for SARS-CoV-2 RNA was performed on lung tissue. Results.— Of 44 specimens (43 patients; median age, 59.3 years; 26 [60.5%] male) features of acute lung injury (ALI) were seen in 39 (88.6%), predominantly organizing pneumonia and diffuse alveolar damage, up to 298 days after onset of COVID-19. Fibrotic changes were found in 33 specimens (75%), most commonly fibrotic diffuse alveolar damage (n = 22) and cicatricial organizing pneumonia (n = 12). Time between acquiring COVID-19 and specimen was shorter in patients with diffuse ALI (median, 61.5 days) compared with patients with focal (140 days) or no ALI (130 days) (P = .009). Sixteen (of 20; 80%) SARS-CoV-2 reverse transcription droplet digital polymerase chain reaction tests were positive, up to 174 days after COVID-19 onset. Time between COVID-19 onset and most recent computed tomography in patients with consolidation on imaging was shorter (median, 43.0 days) versus in patients without consolidation (87.5 days; P = .02). Reticulations were associated with longer time to computed tomography after COVID-19 onset (median, 82 versus 23.5 days; P = .006). Conclusions.— ALI and SARS-CoV-2 RNA can be detected in patients with COVID-19 for many months. ALI may evolve into fibrotic interstitial lung disease.

Introduction: Uric acid (UA) level within carotid plaque specimens and its association with cerebrovascular events has not been detected or quantified. Systemically, serum uric acid (SUA) is a marker of inflammation and risk factor for atherosclerosis. However, its association with carotid plaque instability and subsequent cerebrovascular events remains unclear. Hypothesis: We hypothesized that UA may play a role in carotid artery atherosclerosis and stroke pathogenesis. In patients undergoing carotid endarterectomy (CEA), we aimed to determine whether UA is present differentially in carotid plaques of symptomatic versus asymptomatic patients and whether SUA is associated with cerebrovascular symptoms before surgery and major adverse cardiovascular events (MACE) in the follow-up to CEA. Methods: We prospectively collected 32 carotid plaques during CEA. We qualitatively assessed the presence of UA by using Gomori methenamine silver (GMS) staining and immunohistochemistry with anti-UA antibodies. We extracted and measured the quantity of UA in carotid plaques by using an enzymatic colorimetric assay. A retrospective analysis of a clinical database of 534 consecutive patients who underwent CEA was performed. We defined as symptomatic those patients with history of stroke, TIA and amaurosis fugax. Results: UA positive staining was detected in higher number of carotid plaques from symptomatic compared to asymptomatic patients on both staining, GMS [20 (86.9%) vs 2 (22.2%); p=0.001] and immunohistochemistry anti-UA [16 (69.5%) vs 1 (11.1%); p=0.004]. Moreover, we found a significantly higher concentration of UA in carotid plaque from symptomatic compared to asymptomatic patients [25.1 (9.5) μg/g vs 17.9 (3.8) μg/g; p=0.021]. SUA level in patients prior to CEA was significantly higher in the symptomatic compared to the asymptomatic group [6.0 (4.8-7.1) mg/dL vs 5.2 (4.4-6.3) mg/dL; p<0.001] and it was significantly higher in patients who developed MACE after CEA versus those that did not [6.0 (4.8-7.1) mg/dL vs 5.4 (4.5-6.6) mg/dL; p=0.021]. Conclusions: UA may provide a mechanistic explanation as systemic biomarker and potential tissue contributor for carotid plaque instability and subsequent cerebrovascular and cardiovascular symptoms.

Background: Transthyretin amyloid cardiomyopathy (ATTR-CM) is one of the most common types of cardiac amyloidosis. Amyloid cardiomyopathy more commonly affects men, elderly, and 3% to 4% of the African-American population. ATTR-CM suspicion and diagnosis is challenging; however, awareness of the disease is increasing, and best practices to identify it are being proposed. The approach to suspected cases of ATTR-CM relies on the presence of heart failure, red flag signs and symptoms, and age >65 or >70 for men and women respectively. Little is known about cases when it presents in early ages. Case: We report a 62-year-old African American male with past medical history of hyperlipidemia, prostate cancer, hypertension, bilateral carpal tunnel surgery that had debuted with a cardiac arrhythmia at age 55 and was diagnosed with heart failure several years later. Restrictive cardiomyopathy was suspected, and genetic screening was sent for ATTRm which confirmed a pathogenic trasnthyretin gene mutation. Endomyocardial biopsy was performed which confirmed cardiac amyloid deposition. Discussion: ATTR-CM is a rare disease with an increasing prevalence. Cases with out of proportion signs and symptoms of heart failure with preserved ejection fractions should raise the suspicion of ATTR-CM despite age.

Carotid plaque vulnerability features beyond the degree of stenosis may play a key role in the pathogenesis and recurrence of ischemic cerebrovascular events. This study sought to compare intraplaque hemorrhage (IPH) as a marker of plaque vulnerability in symptomatic patients with mild (<50%), moderate (50%–69%), and severe (≥70%) carotid artery stenosis. We included patients who experienced ischemic cerebrovascular events with no other identifiable sources and underwent carotid endarterectomy for mild (n=32), moderate (n=47), and severe (n=58) carotid artery stenosis. The degree of stenosis and imaging hallmarks were assessed by computed tomography angiography or magnetic resonance angiography. Plaque specimens were stained with hematoxylin and eosin and Movat pentachrome staining. Carotid plaques of patients with mild stenosis had a higher extent of IPH (%) on tissue analysis compared with patients with moderate (mild, 15.7% [interquartile range, 7.8%–26.7%]; moderate, 3.9% [0.0%–9.2%]; P <0.001) and severe carotid artery stenosis (mild, 15.7% [interquartile range, 7.8%–26.7%]; severe, 2.5% [interquartile range, 0.0%–11.2%]; P <0.001). When considering the degree of carotid artery stenosis as a continuous variable, a lower lumen narrowing was associated with higher extent of IPH ( P <0.001; R, −0.329). Our major finding is the association of IPH with mild carotid artery stenosis based on histological analysis. The current study may suggest that IPH potentially plays a role in the mechanism of stroke in patients with nonobstructive carotid stenosis.

Background Using computed tomography angiography to differentiate between components of carotid atherosclerotic lesions remains largely elusive. This study sought to validate a semi-automated software for computed tomography angiography plaque analysis using histologic comparisons. Materials and Methods A retrospective review was performed of consecutive patients that underwent a carotid endarterectomy, with pre-procedural computed tomography angiography imaging of the cervical arterial vasculature available for review. Images were evaluated using a commercially-available software package, which produced segmented analyses of intraplaque components (e.g. intraplaque hemorrhage, lipid-rich necrotic core, and calcifications). On imaging, each component was assessed in terms of its (1) presence or absence, and (2) both volume and proportion of the total plaque volume (if present). On histological evaluation of carotid endarterectomy specimens, each component was evaluated as an estimated proportion of total plaque volume. Results Of 80 included patients, 30 (37.5%) were female. The average age was 69.7 years (SD = 9.1). Based on imaging, intraplaque hemorrhage was the smallest contributor to plaque composition (1.2% of volumes on average). Statistically significant linear associations were noted between the proportion of intraplaque hemorrhage, lipid-rich necrotic core, and calcifications on histology and the volume of each component on imaging ( p values ranged from 0.0008 to 0.01). Area under curve were poor for intraplaque hemorrhage and lipid-rich necrotic core (0.59 and 0.61, respectively) and acceptable for calcifications (0.73). Conclusion Semi-automated analyses of computed tomography angiography have limited diagnostic accuracy in the detection of intraplaque hemorrhage and lipid-rich necrotic core in carotid artery plaques. However, volumetric imaging measurements of different components corresponded with histologic analysis.

The mammalian liver's regenerative ability has led researchers to engineer animals as incubators for expansion of human hepatocytes. The expansion properties of human hepatocytes in immunodeficient mice are well known. However, little has been reported about larger animals that are more scalable and practical for clinical purposes. Therefore, we engineered immunodeficient swine to support expansion of human hepatocytes and identify barriers to their clinical application. Immunodeficient swine were engineered by knockout of the recombinase-activating gene 2 ( RAG2 ) and fumarylacetoacetate hydrolase (FAH). Immature human hepatocytes (ihHCs) were injected into fetal swine by intrauterine cell transplantation (IUCT) at day 40 of gestation. Human albumin was measured as a marker of engraftment. Cytotoxicity against ihHCs was measured in transplanted piglets and control swine. We initially detected higher levels of human albumin in cord blood of newborn FAH/ RAG2 -deficient (FR) pigs compared with immunocompetent controls (196.26 ng/dL vs. 39.29 ng/dL, p = 0.008), indicating successful engraftment of ihHCs after IUCT and adaptive immunity in the fetus. Although rare hepatocytes staining positive for human albumin were observed, levels of human albumin did not rise after birth, but declined, suggesting rejection of xenografted ihHCs. Cytotoxicity against ihHCs increased after birth by 3.8% (95% CI: [2.1%–5.4%], p < 0.001) and inversely correlated with declining levels of human albumin ( p = 2.1 × 10 −5 , R 2 = 0.17). Circulating numbers of T cells and B cells were negligible in FR pigs. However, circulating natural killer (NK) cells exerted cytotoxicity against ihHCs. NK cell activity was lower in immunodeficient piglets after IUCT than in naive controls (30.4% vs. 40.1%, p = 0.011, 95% CI for difference [2.7%–16.7%]). In conclusion, ihHCs were successfully engrafted in FR swine after IUCT. NK cells were a significant barrier to expansion of hepatocytes. New approaches are needed to overcome this hurdle and allow large-scale expansion of human hepatocytes in immunodeficient swine. Impact statement There is currently a need for robust expansion of human hepatocytes. We describe an immunodeficient swine model into which we engrafted immature human hepatocytes (ihHCs). We identified the mechanism of the eventual graft rejection by the intact NK cell population, which has not been previously shown to have a significant role in xenograft rejection. By both improving engraftment and reducing NK cell-mediated cytotoxicity toward the graft through intrauterine cell transfer, we confirmed the presence of residual adaptive immunity in this model of immunodeficiency and the ability to induce hyposensitization in the NK cell population by taking advantage of the fetal microenvironment.