Large Clot Research Articles

New Evidence on a Distinction between Aβ40 and Aβ42 Amyloids: Thioflavin T Binding Modes, Clustering Tendency, Degradation Resistance, and Cross-Seeding.

The relative abundance of two main Abeta-peptide types with different lengths, Aβ40 and Aβ42, determines the severity of the Alzheimer’s disease progression. However, the factors responsible for different behavior patterns of these peptides in the amyloidogenesis process remain unknown. In this comprehensive study, new evidence on Aβ40 and Aβ42 amyloid polymorphism was obtained using a wide range of experimental approaches, including custom-designed approaches. We have for the first time determined the number of modes of thioflavin T (ThT) binding to Aβ40 and Aβ42 fibrils and their binding parameters using a specially developed approach based on the use of equilibrium microdialysis, which makes it possible to distinguish between the concentration of the injected dye and the concentration of dye bound to fibrils. The binding sites of one of these modes located at the junction of adjacent fibrillar filaments were predicted by molecular modeling techniques. We assumed that the sites of the additional mode of ThT-Aβ42 amyloid binding observed experimentally (which are not found in the case of Aβ40 fibrils) are localized in amyloid clots, and the number of these sites could be used for estimation of the level of fiber clustering. We have shown the high tendency of Aβ42 fibers to form large clots compared to Aβ40 fibrils. It is probable that this largely determines the high resistance of Aβ42 amyloids to destabilizing effects (denaturants, ionic detergents, ultrasonication) and their explicit cytotoxic effect, which we have shown. Remarkably, cross-seeding of Aβ40 fibrillogenesis using the preformed Aβ42 fibrils changes the morphology and increases the stability and cytotoxicity of Aβ40 fibrils. The differences in the tendency to cluster and resistance to external factors of Aβ40 and Aβ42 fibrils revealed here may be related to the distinct role they play in the deposition of amyloids and, therefore, differences in pathogenicity in Alzheimer’s disease.

Changes in Lung Perfusion in Patients Treated with Percutaneous Mechanical Thrombectomy for Intermediate-Risk Pulmonary Embolism

BackgroundCurrent pulmonary embolism treatment options rely heavily on anatomical clot location. However, anatomical location does not necessarily determine adverse outcomes; rather, clinical severity is secondary to the degree of perfusion impairment. Dual-energy computed tomography pulmonary angiogram (DE-CTPA) can map perfusion at the time of pulmonary embolism diagnosis. Single-photon emission computed tomography ventilation-perfusion scans allow for perfusion tracking similar to DE-CTPA. MethodsWe present 3 patients with intermediate-risk pulmonary embolism treated with mechanical thrombectomy using the Inari FlowTriever System (Inari Medical, Irvine, Calif). Lung perfusion scoring was applied to pre-procedure and post-procedure imaging. We graded perfusion of each lobe in 3 planes. If the entire lobe was perfused, a score of 3 was assigned. If lung perfusion is normal, total perfusion score is 15. All patients had pre-procedure and follow-up transthoracic echocardiograms. ResultsAll 3 patients were diagnosed with pulmonary embolism via DE-CTPA that showed right ventricle strain and had deep venous thrombosis. Following mechanical thrombectomy, patients immediately experienced improvement in perfusion score; scores continued to improve at follow-up. All patients also had improvement in right ventricle size or function on follow-up echocardiogram. DiscussionIntermediate-risk pulmonary embolism often has large initial clot burden that predicts residual pulmonary vascular obstruction. Residual pulmonary vascular obstruction is associated with increased risk of death, recurrent thrombus, and chronic thromboembolic pulmonary hypertension. Clot removal via thrombectomy may decrease the prevalence of residual pulmonary vascular obstruction by improving lung perfusion. We found that mechanical thrombectomy increased lung perfusion immediately and at follow-up assessments.

Advances in Acute Ischemic Stroke Therapy.

The treatment of acute ischemic stroke continues to advance. The mainstay of treatment remains intravenous thrombolysis with alteplase. Recent studies demonstrated that later treatment with alteplase is beneficial in patients selected with advanced imaging techniques. Tenecteplase has been evaluated as an alternative thrombolytic drug and evidence suggests that it is as least as effective as alteplase and may lyse large vessel clots more effectively. Endovascular therapy with mechanical thrombectomy has now been shown to be beneficial up to 24 hours after stroke onset in carefully selected patients with proximal, large vessel occlusions. Ongoing studies are evaluating the effectiveness of thrombectomy in patients with more distal vessel occlusions and patients with proximal large vessel occlusions with larger ischemic core volumes and also in patients with milder neurological deficits. Cytoprotection is another potential acute stroke therapy that has not demonstrated efficacy in prior clinical trials. It should be reconsidered as an adjunct to reperfusion and a variety of new clinical trials can be envisioned to evaluate the potential benefits of cytoprotection in patients before and after reperfusion.

Novel Mechanical Thrombosuction in an Ectatic Right Coronary Artery with Large Thrombus Burden: A Case Report

Manual thrombosuction during primary angioplasty in an ectatic coronary artery with large thrombus burden carries the risk of incomplete thrombus extraction and thrombus migration. Here, the authors describe a case in which a novel mechanical thrombosuction device with a large lumen and sustained power aspiration enabled the safe and effective complete extraction of a large unfragmented clot. Further studies with such devices are required to shed light on the efficacy and safety of mechanical thrombosuction in coronary interventions.

Rupture of the abdominal aorta artery due to self-inflicted injuries in a young man.

Introduction and importanceIntentional drug poisoning is the most common method of suicide in the population. Self-inflicted injuries are usually limited to parts of the body that are easily accessible with one's hand, such as the neck, thorax, or upper extremities. Penetrating aortic trauma has a high mortality rate, and open surgery is frequently required.Case presentationWe report a 19-year-old man who stabbed himself in the anterior abdomen with a kitchen knife after ingesting numerous benzodiazepine tablets, resulting in a rupture of intra-abdominal viscera, including the abdominal aorta artery.Clinical discussionAortic penetrating injuries have a high mortality rate. The retroperitoneal position of the abdominal aorta and the minor size of the rupture were associated with the formation of very large clots, which were essential in controlling bleeding and hemodynamic abnormalities.ConclusionIn any patient with drug poisoning following committing suicide, in case of acute abdominal symptoms and hemodynamic disturbance, after controlling the level of consciousness, respiratory, and hemodynamic correction of the patient, immediate consultation with the surgical service should be considered.

A phenomenological investigation on near-wall bubble behavior close to CHF in flow boiling

The insight information of subcooled flow boiling is very important for the development of boiling crisis mechanistic model. In this paper, visual experiment is carried out in a vertical square channel with a heating rod with diameter of 9.5 mm. Based on the near-wall bubble behavior captured by a high-speed camera, combined with advanced image post-processing technique developed in-house, the qualitative and quantitative analysis of flow boiling behavior near the heating wall are presented when approaching the CHF (Critical Heat Flux). According to the visual experimental study, a detailed discussion on the phenomena before CHF and during the CHF is presented. With high heat flux, periodic large vapor clot passes with relatively constant frequency. Then periodic wavy vapor layer and liquid film clearly appear in the near-wall region when the working condition is extremely close to the CHF. It is found that high thermal-hydraulic parameters, including system pressure, mass flux and inlet subcooling, prevent the formation of thick vapor layer, and this is a significant precursor to trigger boiling crisis. This implies that the possibility of triggering boiling crisis is reduced due to the difficulty in forming thicker vapor layer, and lead to higher CHF value. Additionally, a prediction of wavelength between two-phase layers is proposed by combining visual observations and instability theory. The predicted results show good agreement compared with experimental data. Those results can provide predictions of key interfacial feature parameters for developing CHF mechanistic model.

A137 AN ELUSIVE GASTROINTESTINAL BLEED: A CASE OF RUPTURED CYSTIC ARTERY PSEUDOANEURYSM WITH PREVIOUS BILLROTH-II SURGERY

Abstract Background Cystic artery pseudoaneurysm (CAP) is a rare but potentially life-threatening cause of upper gastrointestinal (GI) bleeding and requires urgent intervention. Aims To describe the clinical enigma of CAP in the context of distorted anatomy and discuss management. Methods Case report and review of literature Results Case Report A healthy 91-year-old man with a remote history of gastric ulcer perforation leading to Billroth-II surgery 40 years ago presented to a community hospital with melena. He had no abdominal pain and liver enzymes were normal. His hemoglobin was 97 g/L (from 137 g/L the month prior) with a BUN:Cr ratio of 50.6 mg/dL and white cell count of 14.4 x109/L. Upper endoscopy identified a large adherent clot in the stomach that could not be dislodged and was suspected to obscure the culprit lesion. Afferent and efferent limbs from previous Billroth-II surgery were identified but not intubated. He was managed supportively with acid suppression and blood transfusion, but his hemoglobin continued decreasing, leading to transfer to a tertiary centre. Upon arrival he had new-onset abdominal pain, rigors, and diaphoresis with a heart rate of 175 beats/minute and blood pressure of 75/40 mmHg. After resuscitation, emergent CT angiogram demonstrated acute contrast extravasation into the gallbladder in keeping with a ruptured CAP. He underwent successful coiling of the cystic artery. Following this, his abdominal pain resolved, and hemoglobin stabilized. Repeat endoscopy demonstrated Billroth-II anatomy without bleeding lesion. He was treated with antibiotics for presumed cholecystitis and discharged home for outpatient cholecystectomy. Literature Review CAP is a rare cause of hemobilia, described only in case reports. The complete hemobilia triad of jaundice, right upper quadrant pain, and GI bleeding is absent in the majority of cases, requiring endoscopic evaluation of the ampulla of Vater or contrast CT. The most common causes of CAP are iatrogenic from cholecystectomy, cholecystitis, gallstones, and malignancy. These mechanisms, whether through trauma or inflammation, lead to damage of the gallbladder wall and the cystic artery. Contained CAP can lead to intermittent bleeding whereas ruptured CAP causes brisk arterial bleeding, necessitating arterial embolization or emergent cholecystectomy. In cases of biliary obstruction, either from the original process or subsequent blood clot at the ampulla, ERCP can lead to successful decompression. Conclusions We present a case of ruptured CAP which eluded diagnosis due to diagnostic rarity, lack of clinical clues, and distorted anatomy. CAP should be considered with a history of recent cholecystectomy, acute cholecystitis, or gallstones. Maintaining an index of suspicion for rare causes of GI bleeding can ensure timely diagnosis and escalation to the appropriate level of care. Funding Agencies None

Comparative analysis between 1-D, 2-D and 3-D carotid web quantification

BackgroundCarotid webs (CaW) are now recognized as a cause of ischemic stroke in young patients. The thromboembolic potential appears related to the CaW’s morphology and consequent impact on local flow...

Catastrophic antiphospholipid syndrome (Asherson’s syndrome) caused by a suspected intestinal neuroendocrine tumor: a case report

Background. Every year, the number of people with rare forms of the disease is increasing worldwide. One of these is the catastrophic antiphospholipid syndrome — Asherson’s syndrome. To date, it is being actively studied, but the pathophysiological mechanisms of its development have not yet been fully investigated. Our work is the first attempt to describe Asherson’s syndrome on the example of a clinical case in Ukraine. Objective: to determine the factors and mechanisms that led to the death of a patient with Asherson’s syndrome in Ukraine. Materials and methods. The structural-logical analysis and the clinical-statistical method were used. Results. Based on clinical and laboratory criteria, our medical team established a clinical diagnosis of systemic lupus erythematosus complicated by a catastrophic antiphospholipid syndrome (CAPS). Despite treatment with glucocorticoids and anticoagulants according to international guidelines, the patient died. The autopsy results showed that the immediate cause of death was a large blood clot that blocked the pulmonary artery and its main branches. Histological examination revealed thrombosis of small vessels of the kidneys and brain; a neuroendocrine tumor (G2; pT3pNxpM1b) of the small intestine with metastases to the liver, brain, myocardium and kidneys was suspected. An additional immunohistochemical study was performed to clarify the histological diagnosis. The morphological picture and results of immunohistochemical study mostly correspond to the moderately differentiated (G2) non-keratinizing squamous cell carcinoma (ICD-O code: 8070/3) with damage to the walls of the small intestine, liver, lungs, kidneys, myocardium and brain. Conclusions. These data emphasize that despite the rarity of Asherson’s syndrome, it is always necessary to consider its probability in the presence of signs of multiple thrombosis and multiple organ failure. Because its development is the result of serious diseases, including connective tissue diseases, malignancies, infections, the etiotropic and pathogenetic treatment can prevent the development of CAPS and death.

Real-Time MRI-Guided Stereotactic Aspiration of Spontaneous Intracerebral Hematoma: A Preclinical Feasibility Study.

Minimally invasive surgical techniques have reinvigorated the role of surgical options for spontaneous intracranial hematomas; however, they are limited by the lack of real-time feedback on the extent of hematoma evacuation. To describe the development of a MRI-guided catheter-based aspiration system, the ClearPoint Pursuit Neuroaspiration Device (ClearPoint Neuro) and validation in phantom models. In this preclinical experimental trial, 8 phantom brains with skull models were created to simulate an intracranial hematoma with 2 clot sizes, 30 cc (small clot) and 60 cc (large clot). After registration, the aspiration catheter (Pursuit device) was aligned to the desired planned trajectory. The aspiration of the clot was performed under real-time MRI scan in 3 orthogonal views. The primary end point was reduction of the clot volume to less than 15 cc or 70% of the original clot volume. Successful completion of clot evacuation was achieved in all models. The average postaspiration clot volume was 9.5 cc (8.7 cc for small clots and 10.2 cc for large clots). The average percentage reduction of clot volume was 76.3% (range 58.7%-85.2%). The average total procedure time (from frame registration to final postaspiration clot assessment) was 50 min. The average aspiration time was 6.9 min. This preclinical trial confirms the feasibility and efficacy of MRI-guided aspiration under real-time image guidance in simulation models for intracranial hematoma. Clinical use of the system in patients would further validate its efficacy and safety.

Analysis of asphaltene nano-aggregates formation using dynamic light scattering: Experimental and kinetic modeling

In this study, the kinetics of the aggregate behavior of asphaltene particles in a very dilute concentration range of 6.25-50 mg/L in toluene was investigated using the dynamic light scattering (DLS) technique. Then, the kinetics of asphaltene aggregation was analyzed by a proposed model based on the mass action law concept. Also, the presence of silica nanoparticles, SiO2-NPs, was investigated for the analysis of asphaltene aggregation behavior. The DLS results showed that by selecting the optimum sonication time of 6 min, asphaltene monomers (1 nm) at concentrations of 6.25, 12.5, and 25 mg/L did not incline to form asphaltene nano-aggregates over time. However, at a concentration of 50 mg/L, at the initial moments, the asphaltene particles began to form large clusters and clots. The results obtained by model optimization showed good agreement with experimental data with acceptable accuracy and mean absolute percentage errors of 10.41% and 5.21% for concentrations of 6.25 and 12.5 mg/L, respectively. Also, the results showed that in the mixing ratios of and of asphaltene concentration to the concentration of nanofluid, SiO2-NPs were placed between the polar particles of asphaltene and created a new structure in the colloidal solution that prevented the self-association of asphaltene molecules and increased the kinetic stability of the asphaltene particles.

Abstract 10768: Use of Cellular Indices to Predict All-Cause Mortality Outcomes in Patients with Pulmonary Embolism

Introduction: Pulmonary embolism (PE) is a life-threatening condition with variable severity that results from dysregulation of complex inflammatory and hematologic processes. Current risk stratifications suffer from a low positive predictive variable. Complete blood count data offers a relatively low cost and easily accessible opportunity to supplement current risk models. We aim to identify trends in blood indices in patients with pulmonary embolism to stratify all-cause mortality. Materials and Methods: Patients with acute PE (n=231) confirmed on diagnostic imaging were followed during a three-year period for all-cause mortality. Complete blood count with differential was obtained within 24 hours of PE diagnosis through the electronic medical records system. SPSS Statistics was used to conduct bivariate analysis to identify correlations and interquartile ranges of selected indices against mortality. Results: Platelet count (PCC=-0.241, p &It0.001) and platelets/mean platelet volumes (PCC=-0.229, p &It0.001) were found to be negatively correlated with all-cause mortality, while platelets/neutrophils (PCC=0.160, p &It0.021) and neutrophils/lymphocytes (PCC=.244, p &It0.001) had a positive correlation. Values with a p value &It0.05 were declared statistically significant. Patients with active infection, malignancy, or undergoing immunosuppressive therapy were excluded from analysis due to potential confounding. Conclusion: Our study concludes lower levels of platelets are associated with increased mortality in patients with pulmonary embolism. We hypothesize the large clot burden in PE consumes platelets, which results in thrombocytopenia. By leveraging these findings in a clinical setting, we can supplement scoring criteria for pulmonary embolisms to create a more comprehensive model to predict all-cause mortality.

Abstract 1122‐000212: INARI FlowTriever system: First Endovascular Clinical Experience to Treat Diffuse Cerebral Venous Sinus Thrombosis

Introduction : Cerebral Venous Sinus Thrombosis (CVST) is a rare stroke with a wide range of symptomatology at presentation ranging from headache, focal weakness, and coma. Anticoagulation remains the mainstay of treatment. However, in a subset of patients endovascular treatment can be potentially beneficial. Here we describe the first clinical experience using the INARI FlowTriever system to treat a patient presented with focal weakness and found to have diffuse cerebral venous sinus thrombosis. Methods : Case report of CSVT treated with INARI FlowTriever system. Results : A 78‐year‐old female with past medical history of Autoimmune hepatitis and hypothyroidism, was brought to the hospital with left arm weakness. CT head revealed left temporoparietal intraparenchymal hemorrhage and right frontal subarachnoid hemorrhage. CTA of the head and neck revealed extensive CVST involving superior sagittal sinus, bilateral transverse and sigmoid sinuses. She was started on heparin drip. Patient was taken for venous thrombectomy due to persistent left‐sided weakness and multicompartment bleeding while being on anticoagulation for 48 hours. She underwent successful endovascular venous thrombectomy using the INARI FlowTriever system with large clot burden extracted. She was switched to novel oral anticoagulation prior to discharge. During the 3 months follow‐up–MRI brain with and without contrast revealed near complete resolution of the clot burden in the superior sagittal sinus and left transverse/sigmoid complex and her modified Rankin score was at 0. Conclusions : Here we discussed a case of diffuse CVST who was treated initially with heparin drip then underwent endovascular venous thrombectomy using INARI FlowTriever system with large clot burden aspirated with a reasonable safety profile. The INARI medical FlowTriever system is the only mechanical thrombectomy system indicated for the treatment of pulmonary embolism. It is specifically designed for venous clots. It is composed of a trackable large bore aspiration catheter. The INARI FlowTriever Catheter; has 3 expanding nitinol mesh disks; designed to engage and disrupt venous clots and subsequently deliver it to the large bore aspiration catheter. Its larger size makes it an attractive candidate for venous sinus clot retrieval. This study illustrates the first clinical use of INARI thrombectomy device in CVST with a reasonable safety profile. Anticoagulation is the mainstay first line treatment for CVST. However, a small subset of patients would potentially benefit from endovascular treatment but it still uncertain how to select these patients and what is the best timeline to offer early endovascular treatment. Various neuro endovascular techniques has been attempted to treat cerebral venous sinus thrombosis. However; it is unclear which approach and device provides the optimal restoration of venous blood flow. Current neuro endovascular techniques and devices are not particularly designed for CVST pathology treatment and there is need for further innovation and new devices.

A Case Report on Ischaemic Cardiomyopathy with Severe Left Ventricular Dysfunction

Ischaemic cardiomyopathy is a condition that arises when heart muscle is weakened because of coronary artery disease or a heart attack. Left ventricular (LV) dysfunction occurs when the left ventricle is either defective or damaged, thus disrupting healthy function. Normal LV function can be perturbed because of several causes. Some cardiac defects such as valvular malformations or conditions block the passage of blood into the body. Effective and cost-effective treatment is available for such patients that can reduce both morbidity and mortality. Herein, the authors present the case of a 69-year-old male who was brought to the emergency department with a history of hypertension on medication. Later, the patient was transferred to the cardiology department. The patient was brought to the hospital after midnight and had bleeding gums, and experienced bleeding from the site of needle puncture. Earlier reports showed that the international normalised ratio was >6.0, and the 2D echocardiogram showed large LV blood clots, mild LV dysfunction, mild mitral regurgitation, and aortic valve stenosis. Finally, the patient was diagnosed with ischaemic cardiomyopathy associated with LV dysfunction. During discharge, the patient and patient’s representative were counselled in layman’s language about the conditions and prognosis of the disease, the use and adherence to medications, lifestyle modifications, and were advised to review back to the cardiologist.

S2501 Delayed Post Sphincterotomy Bleed and Clot-Induced Cholangitis: A Rare but Life-Threatening Complication of Endoscopic Retrograde Cholangiopancreatography

Introduction: Complication of ERCP are pancreatitis, bleeding and perforation. Post sphincterotomy (PS) bleed, which occurs in about 2% of cases, can be immediate or, very rarely, delayed. This lady had rare, but lethal complications of ERCP such as pancreatitis, severe delayed PS bleed, and clot-induced cholangitis; which was managed endoscopically. Case Description/Methods: A 28-year-old female presented with biliary type of pain abdomen, jaundice and fever. An ultrasonography showed choledocholithiasis, 15mm of size with upstream biliary dilation. Urgent ERCP was done. After biliary cannulation, when sphincterotomy was done, and pus oozed out of the ampulla, suggestive of cholangitis. As attempts to retrieve the calculi failed, mechanical lithotripsy was done and the fragments were removed with the help of basket. After complete CBD clearance, a plastic stent was deployed. There was no immediate PS bleed. But, she developed post ERCP pancreatitis and was managed conservatively. On the 5th day, she complained of melena and syncope. She also developed high-grade fever with chills. She became toxic, with tachycardia and tachypnea. Patient was shifted to ICU, and bedside endoscopy showed bleed in the periampullary area associated with large clots. The patient was intubated because of respiratory distress and started on inotropes and blood transfusion. Again, ERCP was done and blood clots were removed from the periampullary area. The old biliary stent was removed and the CBD was swiped cleared of a large clot that had adhered inside the duct and was causing cholangitis. Multiple aliquots of dilute adrenaline was injected in the peri ampullary area till hemostasis was achieved. A new plastic biliary stent was deployed in the CBD. Post the procedure, the patient began to improve clinically. Discussion: PS bleed can be immediate or very rarely delayed. According to a multivariate analysis, factors for PS bleeding includes coagulopathy, anticoagulation use, cholangitis before ERCP, bleeding during initial sphincterotomy and lower ERCP volume centre. The only risk factor in this patient was cholangitis. There are previously 5 reported cases of delayed PS bleed that has caused clot induced cholangitis. Size of calculus, prior cholangitis, and use of mechanical lithotripsy appear to be the risk factors. Recovery depends on the timing of repeat ERCP.Figure 1.: Endoscopic image showing clot post ERCP.

S2335 An Unusual Source of Massive Upper GI Bleed

Introduction: Pseudoaneurysms affecting main abdominal arteries can manifest as massive gastrointestinal (GI) bleed that carries a high mortality. We report a case of massive upper GI bleed due to splenic artery pseudoaneurysm. Case Description/Methods: A 72-year-old female with a history of Roux-en-Y gastric bypass presented to the emergency department with an episode of hematemesis. During initial evaluation, the patient was unresponsive and pulseless. An orogastric tube returned 100 cc of bloody gastric contents. The patient was started on PPI drip, vasopressors, packed red blood cells transfusion and admitted to intensive care unit. The patient continued to pass large, maroon bowel movements. EGD demonstrated a large adherent clot at gastrojejunal (GJ) anastomosis, and two non-bleeding cratered gastric ulcers with no stigmata of bleeding in the gastric pouch. Repeat EGD for worsening anemia despite transfusions showed fresh blood at the GJ anastomosis and two discrete oozing ulcers, each about 1cm in the gastric pouch. Both lesions were treated with endoscopic therapy. However, the patient continued to have melanotic stools. Third EGD demonstrated an adherent clot at GJ anastomosis. Underneath the clot, was a cratered ulcer with a fistulous tract. Endoscope passed into the fistulous opening with ease, but only a blood clot could be visualized and the scope was withdrawn. The patient remained hypotensive and continued to pass melena. Fourth EGD revealed fresh blood in the entire examined stomach and at the anastomosis site. A source of rapid bleeding could not be identified. Emergent angiogram demonstrated a pseudoaneurysm in the midportion of the splenic artery. A coil and glue embolization of the splenic artery was performed. Post angiogram, there was no recurrence of GI bleeding. After a prolonged hospital course, the patient was discharged to a skilled nursing facility. Discussion: A pseudoaneurysm is a communicating sac within the lumen of the artery. In contrast to true aneurysms, which are usually asymptomatic, pseudoaneurysms are nearly always symptomatic and carry a high risk of rupture. A vascular-enteric fistula is usually found either on endoscopic examination or via angiography. Therapy with angiographic embolization of the pseudoaneurysm is almost always indicated due to high risk of recurrence of severe hemorrhage. If access to the splenic artery fails, endoscopic ultrasound guided coil and glue has recently become an accepted treatment method.Figure 1.: A suspected 11 mm jejunal fistula found in the ulcerated GJ site through which the endoscope was passed, but only blood clot could be visualized.

CLOT OR NOT? AN UNUSUAL CTEPH MIMIC

TOPIC: Pulmonary Vascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Chronic thromboembolic pulmonary hypertension (CTEPH) is an important cause of severe pulmonary hypertension (PH) resulting from pulmonary thromboembolic events with subsequent remodeling of pulmonary vasculature. As one of the few forms of PH with potentially definitive management via pulmonary thromboendarterectomy (PTE), it is imperative that the diagnosis of CTEPH involves careful assessment of the patient's history and available studies, including echocardiograms, ventilation-perfusion (V/Q) scans, computed tomography (CT) scans, right heart catheterizations, and pulmonary angiography. This is especially true when considering other conditions that may mimic the presentation of CTEPH. Herein, we discuss a rare instance of pulmonary artery sarcoma (PAS) mimicking CTEPH in a patient with progressive shortness of breath. CASE PRESENTATION: A 53-year-old female with past medical history remarkable for breast cancer status-post lumpectomy and radiation on adjuvant anastrazole monotherapy presented to an outside hospital for progressive shortness of breath and weight loss. CT chest angiography suggested large pulmonary embolism clot burden, and the patient subsequently underwent catheter-directed thrombolysis with tissue plasminogen activator in bilateral pulmonary artery catheters for 24 hours, with minimal change in mean pulmonary artery pressures between times of insertion and removal. The patient subsequently transferred institutions for consideration of PTE.Review of her CT scans and a new V/Q scan suggested a more lobulated, large volume appearance of the obstructing material in her pulmonary vasculature, raising concern for malignant obstruction as opposed to CTEPH. Subsequent positron emission tomography (PET) CT scan showed equivocal fluorodeoxyglucose (FDG) uptake. The patient was brought to surgery, wherein bilateral intravascular tumor involving the main pulmonary artery extending into both branches was discovered consistent with PAS. The mass was extracted, and the patient was eventually discharged with oncologic follow-up, with post discharge course complicated by metastatic disease currently undergoing her third line of therapy. DISCUSSION: This case demonstrates the complexity diagnosing CTEPH. Important mimics of CTEPH outside of PAS include fibrosing mediastinitis, sarcoidosis, large vessel vasculitis, amongst others. Early clinical clues suggesting against the patient's initial diagnosis include recent weight loss and the lobulated appearance of the pulmonary arterial mass. The prognosis of PAS is extremely poor, due to diagnostic and management delays given the stark similarity to CTEPH, with mean survival rates between 12 and 18 months. (1,2) CONCLUSIONS: Diagnosis and management of CTEPH requires expert, multidisciplinary care, especially with the complexity of properly diagnosing the condition amidst other possible mimicking conditions. REFERENCE #1: Bandyopadhyay D, et al. Primary pulmonary artery sarcoma: a close associate of pulmonary embolism-20-year observational analysis. J Thorac Dis 2016; 8: 2592–2601. REFERENCE #2: Wong HH, et al. Presentation and management of pulmonary artery sarcoma. Clin Sarcoma Res 2015; 5: 3. DISCLOSURES: No relevant relationships by Adam Custer, source=Web Response No relevant relationships by NEVEEN El-Farra, source=Web Response No relevant relationships by Jane Wang, source=Web Response No relevant relationships by Alexander Yuen, source=Web Response

S1581 Hemobilia From an Unlikely Culprit: A Case of a Ruptured Pseudoaneurysm

Introduction: Hemobilia, or bleeding from the hepatobiliary tract, is a rare cause of GI bleeding and jaundice. Most cases of hemobilia are iatrogenic secondary to hepatobiliary interventions, however, trauma and malignancy also represent a major source. We present a case of hemobilia secondary to a hepatic artery pseudoaneurysm, in the setting of acute cholecystitis and metastatic liver disease. Case Description/Methods: A 67-year-old man presented with 3 days of RUQ abdominal pain radiating to the epigastrium. On arrival, he was tachycardic, afebrile, and normotensive. He had RUQ tenderness and icterus. Laboratory findings were significant for leukocytosis, anemia, transaminitis, elevated alkaline phosphatase, and hyperbilirubinemia. An ultrasound of the abdomen was suggestive of calculous cholecystitis and a dilated CBD of 0.8 cm. He underwent a EUS which revealed a dilated CBD with heterogeneous mater. An ERCP showed altered blood at the ampulla. A sphincterotomy was performed and a large blood clot was extracted from the CBD via balloon sweeps. Two plastic stents were then placed for drainage after which brisk arterial bleeding was noted. Urgent angiography revealed evidence of a ruptured pseudoaneurysm arising from the anterior division of the right hepatic artery near segment 8 of the liver. Successful coil embolization was performed. A CT scan of the abdomen revealed rectal thickening and hypoenhancing liver lesions suggestive of metastatic disease. On flexible sigmoidoscopy, a fungating, partially obstructing rectal mass was seen, biopsies of which were positive for invasive adenocarcinoma. Cholecystitis confirmed on HIDA scan was treated conservatively with antibiotics. He was subsequently discharged and started on chemotherapy as an outpatient. He is now planned for a repeat ERCP with stent exchange. Discussion: Hemobilia can masquerade as biliary stones on EUS. Management includes early diagnosis, identification of the source of bleeding, achieving hemostasis, and relieving the obstruction. Transcatheter arterial embolization is preferred if there are any signs of arterial extravasation. Biliary obstruction can be relieved with ERCP and stent placement. In the presence of underlying malignancy, infiltrative disease and its surrounding vascular friability are often implicated. However, a benign etiology should not be overlooked as illustrated in our case. Cholecystitis leading to severe inflammation of the gallbladder bed can cause adjacent arterial wall degeneration and pseudoaneurysm formation.Figure 1.: (A) Superselective catheterization of the right hepatic artery and angiography demonstrating evidence of 1.2 x 0.9 cm pseudoaneurysm/contained perforation, arising from a suspected proximal segment 8 arterial branch. (B) Endoscopic ultrasound demonstrating a dilated common bile duct up to 12 mm, filled with heterogeneous material. The gallbladder wall appears thickened. (C) CT abdomen with contrast showing multiple hypoenhancing liver lesions within the right and left lobes. Surgical coils within the right lobe of the liver consistent with a recent embolization procedure. Common bile duct stent in place, and small foci of pneumobilia. (D) ERCP images showing blood clots protruding from the ampulla. After balloon sweeps and sphincterotomy, two 10 Fr by 7 cm plastic stents were placed in the CBD.Table 1.: Laboratory Values from Admission and Discharge day.

CATASTROPHIC PULMONARY EMBOLISM SUCCESSFULLY TREATED WITH EXTRACORPOREAL MEMBRANE OXYGENATION

TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: Veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) is increasingly recognized as a modality for cardiopulmonary support in high-risk pulmonary embolism (PE). We report a successful application of VA ECMO to support a patient following cardiac arrest secondary to massive saddle PE. CASE PRESENTATION: A 35 year old woman was admitted with new cranial nerve palsies, concerning for neurosarcoidosis versus lymphoma. On hospital day (HD) 11 she became dyspneic and desaturated to 88% on room air; other vitals remained stable. CT chest revealed bilateral pulmonary artery occlusion with right heart strain. NT-proBNP was 3086 pg/mL (ref <125). Multidisciplinary Pulmonary Embolism Response Team (PERT) stratified her as "intermediate-high risk" PE, and recommended therapeutic heparin infusion, with resultant clinical improvement. On HD16 she developed acute chest pain with new tachycardia (HR 130), hypotension (BP 87/65) and increased oxygen requirements. S1Q3T3 pattern was noted on EKG. PE Severity Index (PESI) was 125 (Class IV), and PERT elected for urgent catheter-directed thrombectomy. Prior to procedure she suffered a cardiac arrest, and received ACLS plus systemic thrombolytics, with return of spontaneous circulation after 20 minutes. Post-arrest suction thrombectomy removed large clot burden, but with persistent hypotension despite inhaled nitric oxide, vasopressor and inotropic support and severe right ventricle (RV) systolic dysfunction on echocardiogram, she was peripherally cannulated for VA-ECMO. Her ECMO course was complicated by renal failure requiring renal replacement therapy and hemoperitoneum requiring blood transfusion. Vasopressors were weaned off on ECMO day 4, and she was decannulated on ECMO day 6. She was discharged on HD42, neurologically intact and with recovered cardiac and renal function. DISCUSSION: High-risk PE, defined by acute PE with hemodynamic instability, shock, or cardiac arrest, is associated with high mortality. VA ECMO allows for maintenance of organ perfusion and oxygenation by mechanically bypassing and decompressing the failing RV and pulmonary circulation, offering hemodynamic and respiratory support to allow for reperfusion strategies or spontaneous thrombolysis on heparin. ECMO is increasingly available, with mobile teams allowing for rapid deployment. The literature on ECMO as a rescue therapy for catastrophic PE is limited to small case series, and recent meta analyses were unable to draw definitive conclusions (1, 2). 2019 European guidelines suggest that mechanical cardiopulmonary support may be helpful for high-risk PE with circulatory collapse (3). CONCLUSIONS: This case adds to reports of successful use of VA-ECMO for high-risk PE. Early ECMO consultation and timely appropriate use may prevent sudden cardiac death. Further research is needed to determine what role ECMO may play as an early intervention rather than a salvage procedure. REFERENCE #1: Pozzi, Matteo, et al. "Efficacy and safety of extracorporeal membrane oxygenation for high-risk pulmonary embolism: A systematic review and meta-analysis." Vascular Medicine 25.5 (2020): 460-467. REFERENCE #2: Baldetti, Luca, et al. "Use of extracorporeal membrane oxygenation in high-risk acute pulmonary embolism." Artificial Organs (2020). REFERENCE #3: Konstantinides, Stavros V., et al. "2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS) The Task Force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC)." European heart journal 41.4 (2020): 543-603. DISCLOSURES: no disclosure on file for Stephanie Nonas; No relevant relationships by Jonathan Taylor, source=Web Response

S3073 A Rare Cause of Repeat Hemorrhage: When Cytomegalovirus Hides in the Small Bowel

Introduction: Cytomegalovirus (CMV) is an opportunistic infection typically seen in immunocompromised patients, like those with Human Immunodeficiency Virus (HIV) or organ and stem cell transplant recipients. CMV infections are exceedingly uncommon in the immunocompetent duodenum. We describe such a case, confirmed with biopsy and complicated by severe repeated gastrointestinal hemorrhage. Case Description/Methods: A 74-year-old male with PMH of diabetes, bladder cancer (status-post resection and ureteral stent placement), presented to the ED with general malaise. Was found to meet sepsis criteria and was anemic with bright red blood on rectal exam. CT abdomen and pelvis revealed multiple pelvic abscesses and free air. Stool testing was positive for C. diff and oral vancomycin and IV zosyn were started. Patient was admitted to telemetry and required 3 separate units pRBC for persistent anemia. CTA abdomen performed on day 3 revealed a duodenal bleed. IR performed an embolization, however, patient remained unstable and required intubation and pressors. Anemia continued to worsen, and patient received an additional 2 units pRBC. GI performed a bedside EGD revealing a large clot and duodenal ulcer. Sepsis continued to worsen, and antibiotics were broadened to meropenem and vancomycin. Anemia continued to worsen, and an additional EGD was performed with source control reported. Patient was extubated, and shortly thereafter, had melena, so a final EGD was performed, identifying friable mucosa and a bleeding duodenal vessel. Hemospray and a clip were deployed to contain bleeding, and the patient received a seventh unit of blood. Biopsied duodenal tissue stain showed CMV (Figure 1A) and histology revealed inclusions (Figure 1B), so ganciclovir was started. Recurrent bleeding subsequently resolved, and patient was discharged to subacute rehabilitation to complete a course of IV ganciclovir. Discussion: Though rare in immunocompetent patients, CMV infections should be considered in severe or persistent gastrointestinal bleeds. CMV duodenitis, while very uncommon, has been documented in case reports and is associated with ischemia and massive hemorrhage. In this case, the patient ultimately required seven units of blood, intubation, and numerous endoscopic procedures as a result of CMV duodenitis. Clinical improvement was seen only once the underlying infection was treated and illustrates the need to consider CMV infection in the differential for recurrent gastrointestinal bleeding.Figure 1.: A: Immunohistochemical stain of tissue from duodenal biopsy identifying CMV. B: Histology of duodenal tissue biopsy under high power showing CMV inclusions.