Esophageal Fistula Research Articles

Management of Esophageal Cancer-Associated Respiratory-Digestive Tract Fistulas.

Simple SummaryAs rare but life-threatening complications, respiratory–digestive tract fistulas (RDF) have a major impact on esophageal cancer patients. Furthermore, interdisciplinary treatment concepts are still evolving. This retrospective study aims to assess general strategies for RDF, especially in terms of technical and anatomical approaches. In 51 RDF patients, we proved that bilateral fistula repair and combined surgical and non-surgical intervention correlated significantly with good short- and long-term outcomes.Respiratory–digestive tract fistulas are fatal complications that occur in esophageal cancer treatment. Interdisciplinary treatment strategies are still evolving, especially in anatomical treatment stratification. Thus, this study aims to evaluate general therapeutic strategies for this rare condition. Medical records were reviewed for esophageal cancer-associated respiratory–digestive tract fistula patients treated between January 2008 and September 2021. Fistulas were classified according to being surgery- and tumor-associated. Treatment strategies, clinical success, and survival were analyzed. A total of 51 patients were identified: 28 had tumor-associated fistulas and 23 surgery-associated fistulas. Risk factors for fistula development such as radiation (OR = 0.290, p = 0.64) or stent implantation (OR = 1.917, p = 0.84) did not correlate with lack of symptom control for RDF patients. In contrast, advanced lymph node metastasis as another risk factor was associated with persistent symptoms after treatment for RDF patients (OR = 0.611, p = 0.01). Clinical success significantly correlated with bilateral fistula repair in surgery-associated fistulas (p = 0.01), while tumor-associated fistulas benefited the most from non-surgical (p = 0.04) or combined surgical and non-surgical intervention (p = 0.04) and a bilateral fistula repair (p = 0.02) in terms of overall survival. The therapeutic strategy should aim for bilateral fistula closure. A multidisciplinary, stepwise approach might have the best chance for restoration or symptom control with optimized overall survival in selected patients.

A case report of medically managed esophageal fistula due to complicated esophageal tuberculosis

Introduction and importanceEsophageal TB is a relatively uncommon condition. Mostly, the esophagus can be affected by tuberculosis through direct spread or from mediastinal nodes (rarely from the lungs or bloodstream). The most common symptom is dysphagia, and the diagnosis is confirmed by histology. If left untreated, esophageal tuberculosis can result in bleeding, perforation, fistula formation, aspiration pneumonia, lethal hematemesis, traction diverticula, and esophageal strictures.Case presentationThis is a rare case report of an esophageal fistula caused by tuberculosis in a patient presenting with a cough on eating and weight loss. The patient was subjected to upper gastrointestinal endoscopy, which revealed a cervical esophagus fistula 20 cm from the upper central incisors. Histopathology revealed inflammatory lesions with epithelioid granulomas (granulomatous disease). A mycobacterium sputum examination was performed; the smear was negative. The patient was managed conservatively with anti-tuberculosis treatment (ATT). A follow-up endoscopy after two months revealed that the fistula was closed and clinically improved.Clinical discussionThe quick clearance of contaminated sputum by coordinated peristalsis, paired with upright posture and an intact lower esophageal sphincter, limits the organism's exposure to the esophagus.ConclusionDespite the disease's rarity, if not delayed, it can be efficiently managed with ATT to avoid major complications like esophageal perforation, which necessitates surgery.

Risk factors of esophageal fistula induced by re-radiotherapy for recurrent esophageal cancer with local primary site

PurposeThe purpose of the present study was to investigate risk factors for esophageal fistula (EF) in patients with recurrent esophageal cancer receiving re-radiotherapy with or without chemotherapy.MethodsWe reviewed retrospectively the clinical characters and dosimetric parameters of 96 patients with recurrent esophageal cancer treated with re-radiotherapy in Cancer Hospital Affiliated to Shandong First Medical University between August 2014 and January 2021.Univariate and multivariate logistic regression analyses were provided to determine the risk factors of EF induced by re-radiotherapy.ResultsThe median time interval between two radiotherapy was 23.35 months (range, 4.30 to 238.10 months). EF occurred in 19 patients (19.79%). In univariate analysis, age, T stage, the biologically equivalent dose in the re-radiotherapy, total biologically equivalent dose, hyperfractionated radiotherapy, ulcerative esophageal cancer, the length of tumor and the maximum thickness of tumor had a correlation with the prevalence of EF. In addition, age (HR = 0.170, 95%CI 0.030–0.951, p = 0.044), T stage (HR = 8.369, 95%CI 1.729–40.522, p = 0.008), ulcerative esophageal cancer (HR = 5.810, 95%CI 1.316–25.650, p = 0.020) and the maximum thickness of tumor (HR = 1.314, 95%CI 1.098–1.572, p = 0.003) were risk factors of EF in multivariate logistic regression analysis.ConclusionsThe incidence of EF was significantly increased in patients with recurrent esophageal cancer who underwent re-radiotherapy. This study revealed that age, T stage, ulcerative esophageal cancer and the maximum thickness of the tumor were risk factors associated with EF. In clinical work, patients with risk factors for EF ought to be highly concerned and individualized treatment plans should be taken to reduce the occurrence of EF.

Thoracoscopic repair for esophageal pulmonary fistula after esophageal atresia repair

BackgroundEsophageal pulmonary fistula is a special type of acquired tracheoesophageal fistula that occurs after esophageal atresia/tracheoesophageal fistula repair. Thoracotomy is the surgical repair method currently in use, but postoperative outcomes are unclear. Therefore, we aimed to explore the preliminary safety, effectiveness, and feasibility of thoracoscopic surgical repair of esophageal pulmonary fistula. MethodsWe retrospectively collected data from all patients with esophageal atresia/tracheoesophageal fistula at Beijing Children's Hospital from January 2017 to October 2021, and the clinical characteristics of patients with esophageal pulmonary fistula were analyzed. Clinical information was recorded, and follow-up was performed. ResultsSeven patients (five boys and two girls) were diagnosed as esophageal pulmonary fistula. All patients underwent multiple esophageal surgeries and had esophageal strictures before surgical repair. Clinical manifestations included cough, expectoration, and recurrent pneumonia. Esophagography indicated the location of the fistula with a 100% positive rate, while the positive rate of flexible bronchoscopy and chest computed tomography was 57% (4/7) and 43% (3/7), respectively. Surgical repair was achieved using thoracoscopy with an average operation time of 172 min. All patients developed esophageal strictures, four of which had refractory esophageal strictures and underwent esophageal dilations ranged from 5 to 56 times before this surgery, but anastomotic leakage or acquired esophageal pulmonary fistulas were absent post-surgery. After a median follow-up of 22 months, all patients survived, and the symptoms were well controlled. ConclusionsEsophageal pulmonary fistula is a rare complication of atresia/tracheoesophageal fistula repair. Thoracoscopic surgery is still possible even after previous multiple surgeries in the chest with significant complications and satisfactory results can be achieved in the short term. Level of EvidenceLevel III

Safety and Efficacy of Self-Expandable Metallic Stent Placement Using Low Radial Force Stent for Malignant Dysphagia after Radiotherapy

Introduction: We aimed to investigate the safety and efficacy of self-expandable metallic stent (SEMS) placement in patients with prior radiotherapy (RT) using the Niti-S stent, which is characterized by low radial force, in comparison to patients without prior RT. Methods: A consecutive series of 83 patients who were treated by SEMS placement using Niti-S stent for severe malignant esophageal obstruction or fistula were enrolled. The adverse event rates and efficacy were retrospectively compared between patients with/without prior RT before SEMS placement (RT group [n = 32] versus non-RT group [n = 51]). Results: The incidence rate of major adverse events in the RT group was 6.3% and was not significantly different from that in the non-RT group (5.9%, p = 0.95). Among the RT group, 84.4% were able to resume oral intake within a median of 2 days. Among the patients with fistula, 78.6% could resume oral intake and survive for 73 days after SEMS placement. Cox proportional hazard regression analysis identified significant factors affecting overall survival to be prior RT (hazard ratio [HR]: 1.96), low performance status (HR: 3.87), and subsequent anticancer treatment after SEMS placement (HR: 0.41). However, compared to the non-RT group, the RT group had received longer duration of anticancer treatment before SEMS placement and a lower rate of subsequent anticancer treatment after SEMS placement. Conclusions: With the Niti-S stent, the incidence of major adverse events was sufficiently low even for patients after RT. SEMS with low radial force would be an effective palliative treatment option for patients, regardless of prior RT.

Toxicity of Proton Therapy versus Photon Therapy on Salvage Re-Irradiation for Non-Small Cell Lung Cancer.

This study evaluated the toxicity associated with radiation techniques on curative re-irradiation (re-RT) in patients with thoracic recurrence of non-small cell lung cancer (NSCLC). From 2011 to 2019, we retrospectively reviewed the data of 63 patients with salvage re-RT for in-field or marginal recurrence of NSCLC at two independent institutions. Re-RT techniques using X-ray beams and proton beam therapy (PBT) were also included. Re-RT had a 2-year overall survival (OS) and local progression-free survival of 48.0% and 52.0%, respectively. Fifteen patients experienced grade 3 or higher toxicity after re-RT. The complication rates were 18.2% (4/22) and 26.8% (11/41) in PBT patients and X-ray patients, respectively. Airway or esophageal fistulas occurred in seven patients (11.1%). Fistulas or severe airway obstruction occurred in patients with tumors adjacent to the proximal bronchial tree and esophagus, who underwent hypofractionated radiotherapy (RT) or concurrent chemotherapy, and with a higher dose exposure to the esophagus. In conclusion, salvage re-RT was feasible even in patients with local recurrence within the previous RT field. PBT showed similar survival outcomes and toxicity to those of other techniques. However, thoracic re-RT should be performed carefully considering tumor location and RT regimens such as the fraction size and concurrent chemotherapy.

Over-the-Scope Clip Applications as First-Line Therapy in the Treatment of Upper Non-variceal Gastrointestinal Bleeding, Perforations, and Fistulas.

BackgroundThe over-the-scope clip (OTSC) is an innovative device and has been successfully used in endoscopic treatment, however, there is a lack of clinical data from China. The aim of this study is to investigate the OTSC applications in the treatment of upper non-variceal gastrointestinal bleeding (UNVGIB), perforations, and fistulas in China.MethodsIn total, 80 patients were treated with one OTSC respectively as first-line therapy in our endoscopy center between January 2016 and November 2020. Among them, 41 patients had UNVGIB, 34 patients had perforations, and five patients had fistulas. The technical and clinical success rates were used to assess the efficacy of OTSC on the above diseases. In addition, we compared the hemostatic efficacy of OTSC with the standard endoscopic therapy in ulcer bleeding and Dieulafoy's lesion by propensity score matching analysis.ResultsIn general, the OTSCs were applied successfully in all patients and achieved 100% (80/80) technical success. The clinical success of all patients was 91.3% (73/80). Among 41 patients with UNVGIB, the clinical success was 85.4% (35/41); 6 patients presented with recurrence. For patients of Dieulafoy's lesion and under antithrombotic therapy, we found that OTSC treatment had both efficient and reliable hemostasis effects. In addition, according to the characteristics of ulcers, site of bleeding lesion, and Blatchford score, all patients received similar and reliable clinical success rates. After propensity score matching, we found that OTSC treatment had low rebleeding rates when compared with standard endoscopic therapy in both Dieulafoy's lesion (15.0 vs 30.0%) and ulcer bleeding (17.6 vs 29.4%). Among 34 patients with perforations, the clinical success was 100% (34/34). Among five patients with fistulas, only one patient failed in maintaining the OTSC before esophageal fistula healing, and the clip achieved an overall clinical success of 80% (4/5).ConclusionThe OTSC represents a safe and effective endoscopic therapy for UNVGIB, perforations, and fistulas as first-line treatment, especially for Dieulafoy's lesion or patients under antithrombotic therapy for UNVGIB, etc. However, OTSC application in these specific lesions or patients lacks adequate evidence as first-line treatment. Therefore, further larger sample and multi-center clinical trials are required to improve its indications in clinical treatment.

Use of the endoscopic vacuum therapy technique for the treatment of esophageal fistulas: an integrative review and clinical case series study

Esophageal fistula is a rare disease with a mortality rate of up to 31% of cases and with multifactorial causes. The most common etiologies of esophageal perforation are associated with iatrogenic, foreign body ingestion, as well as cases of lesions of neoplastic origin. Consisting of an innovative therapy with efficiency not yet evaluated in clinical studies, the present study sought to report a series of cases of patients with esophageal fistulas undergoing treatment with endoscopic vacuum therapy (VTE) assisted by the service team of a tertiary public hospital. from the state of Ceará in order to contribute with evidence that reinforces the role of VTE in the closure of esophageal perforations of different etiologies. In addition, in order to contextualize the importance of the cases presented, we carried out an integrative review in order to list the main clinical findings on the use of VTE available in the world scientific literature. There was a need for continuous development of new clinical studies that seek to improve and validate the use of VTE for the safe and effective treatment of esophageal fistulas, emphasizing that treatment with VTE can maximize the therapeutic response, bringing a greater and better clinical patient satisfaction.

A Nomogram for Predicting the Risk of Radiotherapy-Related Esophageal Fistula in Esophageal Cancer Patients.

BackgroundTo construct and validate a nomogram for predicting the risk of esophageal fistula in esophageal cancer patients receiving radiotherapy.MethodsA retrospective nested case–control study was performed, in which a total of 81 esophageal fistula patients and 243 controls from 2014 to 2020 in the First Affiliated Hospital of Anhui Medical University were enrolled. Factors included in the nomogram were determined by univariate and multiple logistic regression analysis. The following methods including ROC curve, C-index, calibration curves, Brier score, and decision curve analysis (DCA) were adopted to evaluate this nomogram.ResultsMultivariate logistic regression analysis showed that T4 stage, level 4 stenosis, ulcerative esophageal cancer, prealbumin, and maximum diameters of GTV and NLR were the independent risk factors of esophageal fistula. Accordingly, a nomogram incorporating the aforementioned six parameters was constructed. The AUC was 0.848 (95% CI 0.901–0.895), indicating a high prediction accuracy of this nomogram. Further evaluation of this model showed that the C-index was 0.847, while the bias-corrected C-index after internal validation was 0.833. The Brier score was 0.127. The calibration curves presented good concordance, and the DCA revealed promising clinical application.ConclusionsThe nomogram presents accurate and applicable prediction for the esophageal fistula risk in esophageal cancer patients receiving radiotherapy.

Mediastinal pancreatobiliary pseudocysts

To select the optimal treatment for uninfected and suppurative rare mediastinal pancreatobiliary pseudocysts. There were 10 patients with mediastinal pancreatogenic (n=9) and biliogenic (n=1) pseudocysts formed through esophageal (n=9) and aortic (n=1) hiatus of the diaphragm. All patients were divided into groups: group A - uninfected pancreatic pseudocysts (n=5) formed through esophageal hiatus; group B - 5 patients with suppurative pancreatogenic (n=4) and biliogenic (n=1) mediastinitis complicated by biliopleuroesophageal (n=1), pancreatoesophageal (n=1) and pancreatopleural (n=2) fistulas. In the group A, simultaneous procedures (n=5) were performed depending on pancreatic parenchyma and pancreatic duct destruction. Distal ductal obstruction required Frey procedure (n=3). If distal duct was patent, we resected cyst-containing pancreatic tail (n=2). Early and long-term results were favorable. In the group B, mediastinitis persisted for a long time with normal temperature as a rule. In our opinion, mild course is associated with gradual introduction of purulent tissues into mediastinum and development of a tissue barrier. Two-stage surgeries were performed in patients with pancreatopleural empyema. Mediastinitis lasting 6-8 weeks caused perforation of the lower third of esophagus (n=2) and death of 1 patient. Risk factors of mediastinal pseudocysts: hypertension in pancreatic duct and pseudocysts, immobile cicatricial tissues of omental bursa, proximity of subdiaphragmatic structures to esophageal and aortic hiatus of the diaphragm. Pressure in aortic canal (mmHg) is 10 times higher than in esophageal canal that increases migration through the esophageal hiatus. It is advisable to distinguish pancreatoesophageal and biliopleuroesophageal fistulas. Uninfected mediastinal pseudocysts require simultaneous procedures, pancreatopleural empyema - two-stage interventions. Therapy is recommended in patients with esophageal fistula and no severe symptoms and intoxication.

Pericardial–Esophageal Fistula: A Rare but Increasing Complication of Cardiac Ablation

Pericardial–esophageal fistula and/or atrial–esophageal fistula after cardiac ablation is nearly universally fatal if not detected and treated expeditiously. This condition should be assumed and ruled out in anyone with a recent history of cardiac ablation presenting with signs of sepsis, pneumomediastinum, pneumopericardium, or chest pain. Computed tomography scan of the chest is a rapid and a sensitive diagnostic modality. Tenets of treatment and repair consist of preventing an air embolism, repairing the esophageal perforation and atrial defect, and interposing autologous tissue between the esophagus and heart.

A Case Report of Congenital Oesophageal Atresia with Tracheo-Oesophageal Fistula and Review of the Literature

Introduction Congenital oesophageal atresia (COA) refers to a congenitally interrupted oesophagus. It is commonly referred to in the literature as oesophageal atresia (OA) with or without tracheo oesophageal fistula (TOF) but acquired TOF is a different entity. Case Report We present a case of OA with TOF which was not suspected antenatally despite the presence of polyhydramnios. The baby presented with respiratory distress and excessive oral secretions at the age of 3-hours following initiation of breastfeeding. Thorascopic repair was performed on the second day of life. The pre-, intra- and post-operative course was smooth with no major challenges. There was no associated anomalies in our case following thorough systemic evaluation including brain ultrasound, abdominal ultrasound, skeletal survey, ophthalmic assessment and echocardiography. Conclusion This case demonstrates the importance of maintaining a high index of suspicion for OA when faced with a combination of respiratory distress and persistent frothy oral secretions in a newborn. The antenatal and postnatal diagnostic approaches are discussed with highlights of associated anomalies and pre-operative assessment and management.

Treatment of a 5-year-old child with damage to the esophagus: a case report

Diagnosis and treatment of esophageal injuries remain the most difficult problems in pediatric urgent surgery with high mortality rates. Restoration of function in severe multiple-organ disorders associated with the development of mediastinitis and sepsis in children requires a multidisciplinary approach and the search for alternative treatment methods that help close the esophageal defect and prevent inflammation. These methods include a constant negative pressure system.
 Severe polytrauma led to the development of local inflammation and mediastinitis. The formed esophageal fistula with clinical sepsis required multistage surgical treatment and support of several specialists. At the Regional Childrens Clinical Hospital No. 1 in Vladivostok, at the first stage of treatment, the mediastinum and soft tissues of the neck were drained, which made it possible to stop the spread of inflammation and stabilize the patients condition. The effectiveness of the second stage of surgical treatment using the VAС system was noted in the first 48 h, in the form of a significant reduction in local inflammation and elimination of skin maceration. The VAС system provided adequate drainage of the wound cavity and promoted wound cleansing and growth of granulation tissue. Dissociation of the fistula by applying a gastrostomy made it possible to create favorable conditions for the healing of the esophageal defect and ensure adequate enteral nutrition for the patient.
 Damage to the esophagus with the development of mediastinitis and sepsis are critical conditions; therefore, treatment outcomes depend on early diagnosis and timely surgical treatment. A full-fledged surgical treatment in a specialized hospital helps eliminate complications of damage to effectively restore functions and lead to patient recovery.

An oesophageal fistula associated with cervical osteomyelitis in a 17‐month‐old Holstein heifer

AbstractA 17‐month‐old Holstein heifer was presented to the Centre Hospitalier Universitaire Vétérinaire in Saint‐Hyacinthe (QC, Canada) for abnormal regurgitation. Upon admission, pain was elicited upon mobilisation of the neck and a left‐sided, painless, fluctuating subcutaneous mass was detected in the area of the fifth and sixth cervical vertebrae. An oesophageal fistula with osteomyelitis of the corresponding vertebrae was diagnosed by medical imaging (endoscopy, ultrasound and radiography) and treated medically. No sequelae were reported in the long term. Considering the low prevalence of abnormal regurgitation in cattle, this paper provides the practitioner with an example of a diagnostic approach.

Bevacizumab-induced esophageal pleural fistula during maintenance therapy without radiation in lung cancer

BackgroundEsophageal pleural fistula (EPF) is a rare but fatal complication associated with bevacizumab use; however, cases reports of EPF caused by bevacizumab have not been previously published.Case presentationA 66-year-old male patient diagnosed with stage IV lung adenocarcinoma on April 24, 2020 received 6 cycles of platinum-containing dual chemotherapy combined with bevacizumab followed by three cycles of bevacizumab monotherapy. Five days before admission, he experienced chest tightness, dyspnea, and right chest pain. Bed-side X-ray examination revealed a massive right hydrothorax, and food was found in the extracted pleural effusion. EPF was further confirmed by upper gastrointestinal radiography after oral administration of iohexol. The patient underwent jejunostomy as the distal esophagus could not be identified on gastroscopy, and eventually died of septic shock on January 16, 2021.ConclusionsIt is necessary to pay attention to EPF during bevacizumab use in patients with or without risk factors.

Integrating Clinical Data and Attentional CT Imaging Features for Esophageal Fistula Prediction in Esophageal Cancer.

Background and PurposeThis study aims to develop a risk model to predict esophageal fistula in esophageal cancer (EC) patients by learning from both clinical data and computerized tomography (CT) radiomic features.Materials and MethodsIn this retrospective study, computerized tomography (CT) images and clinical data of 186 esophageal fistula patients and 372 controls (1:2 matched by the diagnosis time of EC, sex, marriage, and race) were collected. All patients had esophageal cancer and did not receive esophageal surgery. 70% patients were assigned into training set randomly and 30% into validation set. We firstly use a novel attentional convolutional neural network for radiographic descriptor extraction from nine views of planes of contextual CT, segmented tumor and neighboring structures. Then clinical factors including general, diagnostic, pathologic, therapeutic and hematological parameters are fed into neural network for high-level latent representation. The radiographic descriptors and latent clinical factor representations are finally associated by a fully connected layer for patient level risk prediction using SoftMax classifier.Results512 deep radiographic features and 32 clinical features were extracted. The integrative deep learning model achieved C-index of 0.901, sensitivity of 0.835, and specificity of 0.918 on validation set with superior performance than non-integrative model using CT imaging alone (C-index = 0.857) or clinical data alone (C-index = 0.780).ConclusionThe integration of radiomic descriptors from CT and clinical data significantly improved the esophageal fistula prediction. We suggest that this model has the potential to support individualized stratification and treatment planning for EC patients.

Clinical comparison between thoracoscopic and thoracotomy repair of Gross type C esophageal atresia

BackgroundTo compare the clinical outcomes between thoracoscopic approach and thoracotomy surgery in patients with Gross type C Esophageal atresia (EA) and tracheoesophageal fistula (TEF).MethodsPatients with Gross type C EA/TEF who underwent surgery from January 2007 to January 2020 at Beijing Children’s Hospital were retrospectively analyzed. The patients were divided into two groups according to surgical approaches. The perioperative factors and postoperative complications were compared among the two groups.ResultsOne hundred and ninety patients (132 boys and 58 girls) with a median birth weight of 2975 (2600, 3200) g were included. The primary operations were performed via thoracoscopic (n = 62) and thoracotomy (n = 128) approach. After comparison of clinical characteristics between the two groups, we found that there were statistically significant differences in associated anomalies, method of fistula closure, duration of mechanical ventilation after surgery, feeding option before discharge, management of pneumothorax, and prognosis (all P < 0.05). To a certain extent, thoracoscopic surgery reduced the incidence of anastomotic leakage and increased the incidence of anastomotic stricture in this study. However, there were no statistically significant differences between the two groups in terms of operative time, postoperative pneumothorax, anastomotic leakage, anastomotic stricture, and recurrent tracheoesophageal fistula (all P > 0.05).ConclusionsThoracoscopy surgery for Gross type C EA/TEF is a safe and effective, minimally invasive technique with comparable operative time and incidence of postoperative complications.

Abstract 9609: Pioneering Cardiac Radioablation With the Use of an MRI Linear Accelerator. Can We Use a Gamma Knife ® to the Heart as We Do in the Brain?

Introduction: VT is often refractory to medical therapy and on rare but critical cases, even EP ablation. Despite investigation into endocardial, mesocardial and occasionally even epicardial ablation for these recalcitrant and deadly arrhythmias, there remains an inability to more effectively, non-invasively, treat VT. Hypothesis: We propose that, paralleling a Gamma Knife ® approach, the use of a novel MRI linear accelerator (MR Linac), the Unity ® (Elekta AB, Stockholm, Sweden), a proof of concept could be applied to highly selected pts with obstinate VT. Methods: A multi-center team with EP, Radiation Oncology and CMR (GE 1.5T) in joint development with Pittsburgh, PA and Utrecht, The Netherlands, developed a completely EP-CMR-guided method for non-invasive VT ablation utilizing S tereo T actic A rrhythmia R adioablation (STAR) with 25 Gy in a single fraction via MR Linac. Results: To evaluate deliverability and applicability of MR Linac plans, four IMRT per clinical scan were developed with varying delivery parameters (7A: 7-beams: 52 o in 70 segments (seg), 7B: 7-beams: 52 o in 100 seg, 15A: 15-beams: 24 o in 70 seg, and 15B: 15-beams: 24 o in 100 seg). We used a 0.2 cm dose grid and a 1% uncertainty via Monte Carlo ® dose calculation. Pt specific QA/QC used ArcCHECK ® (Sun Nuclear, FL) to evaluate individual IMRT plans. 3D CMR with LGE scar fusion for lesion integration guided non-invasive MR LinAc ablation. Accordingly, all IMRT plans were clinically acceptable (&gt;97% of 7-beams and ≥98.0% of 15-beams in 3%/3mm gamma) for MR LinAc VT-ablation successfully with pt target effective arrhythmogenic myocardial ROI volume as ascertained via CMR of 63-99cm 3 . All 4 pts tolerated the 25±5min procedure without esophageal, pericardial or pro-arrhythmic complications and were alive at 30d FU with marked attenuation of VT burden. At 30d FU, no SAE's occurred to include pro-arrhythmias, pericardial effusions or esophageal fistulas. Conclusions: Refractory, complex and anatomically endocardially-remote VT has the potential to be curative, incorporating an analogous Gamma Knife ® approach via MR Linac radioablation heralding a migration to the Unity ® platform. This nearly first-in-man p r oof of concept approach may shepherd a new methodologic era into heretofore intractable VT.

Abstract 13969: Investigation of Comparative Lesion Dimension Between Abbott TactiFlex™ and TactiCath™ SE RF Ablation Catheters

Introduction: This study considers bench tissue ablation with the TactiCath™ Contact Force Ablation Catheter, Sensor Enabled™ (TCSE) and TactiFlex™ Ablation Catheter, Sensor Enabled™ (TFSE) catheters. The TactiFlex™ catheter combines the force-sensing technology of the TactiCath™ SE catheter with a handle and therapy circuit similar to FlexAbility™ Ablation Catheter, Sensor Enabled™. The purpose of this testing was to create models to aid in comparing lesion dimensions (maximum width and depth) between the TactiCath™ and TactiFlex™ catheter designs. Methods: Bovine ventricular tissue was used for ablation; tissue was placed in a saline bath with simulated pulsatile flow across the catheter tip/tissue interface. Ablations (N=512) were conducted at various RF power/duration combinations (20-50W, 5-60s) in parallel and perpendicular orientation, with contact forces of 5g or 15g. Results: A nonlinear regression model was applied to characterize lesion size vs. RF power and duration for both catheters. There is no significant difference in achieved width between catheter designs; however, TFSE produced significantly shallower lesions (p&lt;0.001) for a given RF power/duration combination. The aspect ratio (width divided by depth) of lesions created with TFSE was also found to be significantly greater than with TCSE (p=0.002). The models allow for a translation of conditions to be made between catheter designs. At an RF power of 40W and target force of 15g, a 6mm-deep lesion can be created with TCSE in 18s; a lesion of the same depth can be created with TFSE in 24s (see Figure). Conclusions: At a given RF power, duration and contact force, the TactiCath™ catheter created deeper lesions compared to the TactiFlex™ catheter; however, there was no significant difference in width between the two designs. The higher aspect ratio with TFSE suggests that the shallower lesions may decrease the risk of adverse events (e.g., esophageal fistula) without compromising continuity.

Applicability, efficacy, and safety of over-the-scope clips in children

Over-the-scope clips (OTSCs) are now becoming popular in endoscopy performed in adults for indications such as acute nonvariceal GI bleeding, anastomotic bleeding, and for closure of gastrocutaneous and postgastrostomy fistulae. Varied sizes of clip are available, but even the smallest, 8.5 to 9.8mm in diameter with its loading device on the tip of the endoscope, increases device and endoscope intubation diameters up to 14.65mm. This may present challenges in terms of the size of the patient in whom it might be used. OTSCs appear to be effective and safe in the hands of those who are trained appropriately in endoscopy on adult patients; however, the experience of OTSC application in children is not reported. Here we present results of a service evaluation of this technology at 2 regional/national referral pediatric endoscopy units in the United Kingdom and the United States. Two tertiary centers' databases were searched to identify cases in which OTSCs were used. Demographics, presentation, anthropometry, comorbidities, efficacy, adverse events, and postprocedure follow-up were recorded, with identification of resolution or recurrence. OTSC procedures were performed on 24 occasions in 20 patients (11 girls) between February 2018 and February 2021. Patients had a mean age of 12 years (range, 5-17) and a mean weight of 44.42 kg (range, 18.2-70.3). Indications were nonhealing PEG site fistulae (n= 7), acute nonvariceal upper GI bleeding (ANUGIB) from gastric ulcers (5), ANUGIB from duodenal ulcers (3), nonhealing bleeding anastomotic ulcer (3), esophageal mucocutaneous fistula (1), and gastric perforation (1). Technical success was achieved in all but 1 case (95%), and clinical success was achieved in 18 cases (90%). The OTSC device appears to be effective in children (minimum age 5 years and minimum weight 18 kg) in a limited number of situations including anastomotic ulcer, closure of leaking PEG site, gastric perforation, and bleeding peptic ulcers. The operator should be an experienced endotherapeutic endoscopist with specific OTSC training, and the type and size of the OTSC device should be carefully considered, along with any comorbidities of the patient that may preclude success and/or lead to potential adverse events such as esophageal perforation.