Argon Plasma Coagulation Ablation Research Articles

A127 ENDOSCOPIC MUCOSAL RESECTION WITH HYBRID-ARGON PLASMA ABLATION TO PREVENT RECURRENCE OF 20 MM NON-PEDUNCULATED COLORECTAL POLYPS: A MULTI-CENTER PROSPECTIVE CLINICAL STUDY

Abstract Background Endoscopic mucosal resection (EMR) is the mainstay of therapy for non-pedunculated colorectal polyps 20 mm or larger. Post EMR recurrence rates are about 15% if no margin ablation technique is used. Aims Study aim was to evaluate recurrence rates if hybrid Argon Plasma Coagulation ablation (h-APC) is routinely used after the EMR to ablate the margins, base and vessels. Methods A prospective multi-center study including adult patients (18-89 years) undergoing EMR of non-pedunculated colorectal polyps 20 mm or larger was conducted. h-APC was used to ablate all post EMR margins and to ablate the post EMR resection surface and visible submucosal vessels. The primary outcome was the biopsy proven recurrence rate at the first follow-up colonoscopy (4-6 months after EMR). All the resection sites were visually inspected, and biopsies were obtained from the EMR scar. Secondary outcomes included technical success and complication rates. Results A total of 220 EMRs were performed during the study for h-APC ablation of non-pedunculated colorectal polyps, with a size of ≥20 mm. The average size of the polyps included in the study was 35.7 mm (ranging from 20 mm to 100 mm). Among all resected polyps, 16.8% were sessile serrated lesions (SSL), while 66.3% were adenomas. Additionally, 4 cases of cancer were in the study. The application of hot snare EMR with h-APC ablation was technically successful and completed for all cases. The mean duration of the EMR procedure was 19.6 minutes, ranging from 2.3 to 103 minutes, while the mean duration of h-APC ablation was 6.4 minutes, ranging from 1 to 65 minutes. A total of 147 EMRs with follow up examination (57 EMR involving lesions 40mm or larger) are available currently. The overall recurrence rate was 1.3% (2 out of 147 cases). For cases where complete base ablation was achieved, there was a 0% recurrence rate, including lesions 40mm or larger. For lesions measuring 40mm or larger, the recurrence rate was 1.8% (1 out of 54 cases). Out of the 220 total EMRs conducted, perforations were observed in 0.9% (2 cases, managed conservatively with antibiotics only), and clinically significant bleeding occurred in 2.3% (5 cases). In particular, clinically significant bleeding was noted in 2.3% (4 out of 167 cases) of lesions without clipping and in 4.0% (4 out of 99 cases) for right-sided lesions without clipping. Conclusions In this multicenter study EMR in combination with h-APC demonstrated a high technical success rate with low complication rates and showed very low post EMR recurrence in the preliminary data analysis. Funding Agencies Erbe

Efficacy and Safety of Argon Plasma Coagulation for the Ablation of Barrett's Esophagus: A Systemic Review and Meta-Analysis.

Argon plasma coagulation (APC) is an alternate ablative method to radiofrequency ablation for the treatment of Barrett's esophagus (BE), and it is preferred due to its lower cost and widespread availability. The present meta-analysis aimed to analyze the safety and efficacy of APC for the management of BE. A literature search from January 2000 to November 2022 was done for studies analyzing the outcome of APC in BE. The primary outcomes were clearance rate of intestinal metaplasia and adverse events (AE). Pooled event rates were expressed with summative statistics. A total of 38 studies were included in the final analysis. The pooled event rate for clearance rate of intestinal metaplasia with APC in BE was 86.8% (95% confidence interval [CI], 83.5% to 90.2%), with high-power and hybrid APC having a higher rate compared to standard APC. The pooled incidence of AE with APC in BE was 22.5% (95% CI, 15.3% to 29.7%), without any significant difference between the subgroups, with self-limited chest pain being the commonest AE. The incidence of serious AE was only 0.4% (95% CI, 0.0% to 1.0%), while stricture development was seen only in 1.7% (95% CI, 0.9% to 2.6%) of cases. The pooled recurrence rate of BE was 16.1% (95% CI, 10.7% to 21.6%), with a significantly lower recurrence with high-power APC than standard APC. High-power and hybrid APC seem to have an advantage over standard APC in terms of clearance rate and recurrence rate. Further studies are required to compare the efficacy and safety of hybrid APC with standard APC and radiofrequency ablation.

Factors predictive of persistent fistulas in EUS-directed transgastric ERCP: a multicenter matched case-control study

EUS-directed transgastric ERCP (EDGE) is an established method for managing pancreaticobiliary pathology in Roux-en-Y gastric bypass patients, with high rates of technical success and low rates of serious adverse events (AEs). However, widespread adoption of the technique has been limited because of concerns about the development of persistent gastrogastric or jejunogastric fistulas. Gastrogastric and jejunogastric fistulas have been reported in up to 20% of cases in some series, but predictive risk factors and long-term management and outcomes are lacking. Therefore, our aims were to assess factors associated with the development of persistent fistulas and the technical success of endoscopic fistula closure. This is a case-control study involving 9 centers (8 USA, 1 Europe) from February 2015 to September 2021. Cases of persistent fistulas were defined as endoscopic or imaging evidence of fistula more than 8 weeks after lumen-apposing metal stent (LAMS) removal. Control subjects were defined as endoscopic or imaging confirmation of no fistula more than 8 weeks after LAMS removal. AEs were defined and graded according to the American Society for Gastrointestinal Endoscopy lexicon. Twenty-five patients identified to have evidence of a persistent fistula on follow-up surveillance (cases) were matched with 50 patients with no evidence of a persistent fistula on follow-up surveillance (control subjects) based on age and sex. Mean LAMS dwell time was 74.7 ± 106.2 days. After LAMS removal, argon plasma coagulation (APC) ablation of the fistula was performed in 46 patients (61.3%). Primary closure of the fistula was performed in 26.7% of patients (20: endoscopic suturing in 17, endoscopic tacking in 2, and over-the-scope clips+ endoscopic suturing in 1). When comparing cases with control subjects, there was no difference in baseline demographics, fistula site, LAMS size, or primary closure frequency between the 2 groups (P > .05). However, in the persistent fistula group, the mean LAMS dwell time was significantly longer (127 vs 48 days, P= .02) and more patients had≥5% total body weight gain (33.3% vs 10.3%, P= .03). LAMS dwell time was a significant predictor of persistent fistula (odds ratio, 4.5 after >40 days in situ, P= .01). The odds of developing a persistent fistula increased by 9.5% for every 7 days the LAMS was left in situ. In patients with a persistent fistula, endoscopic closure was attempted in 19 (76%) with successful resolution in 14 (73.7%). Longer LAMS dwell time was found to be associated with a higher risk of persistent fistulas in EDGE patients. APC or primary closure of the fistula on LAMS removal was not found to be protective against developing a persistent fistula, which, if present, can be effectively managed through endoscopic closure in most cases.

S2023 Endometrioma Presenting as a Sigmoid Colon Polyp

Introduction: Endometriosis refers to inflammation caused by active endometrium outside of the uterus. Colonic involvement can give rise to various complications, such as luminal narrowing, obstruction, and even perforation; all which can be avoided with endoscopic mucosal resection (EMR). Our case shows that endometrial implants in the colon can present similarly to colon cancer and should be considered as a potential etiology of findings on colonoscopy. Case Description/Methods: A 45-year-old female (G4P3) presented with a several month history of left lower quadrant abdominal pain, bloating and multiple episodes of blood per rectum. Past medical history was significant for endometriosis with hysterectomy, tubal ligation, and idiopathic thrombocytopenic purpura. She was referred for a rectosigmoid polyp concerning for malignancy. The mass found was a firm, rubbery, 15mm, exophytic sessile polyp positioned on the acute fold of the sigmoid colon. Using an underwater technique, piecemeal EMR was performed. Argon plasma coagulation (APC) ablation was performed on residual adjacent tissue and the resection bed. Histopathology showed endometriosis involving the muscularis propria and submucosa negative for hyperplastic polyp, adenoma or malignancy. Endometriosis stain was positive for CK7 and PAX-8 and negative for CK20 and CDX-2 confirming the diagnosis. Hormone therapy was initiated and showed significant improvement in symptoms (Figure). Discussion: Endometriosis can affect essentially any organ. Intestinal involvement usually presents with symptoms and gross appearance similar to many disorders including cancer or leiomyoma, such as in our case. Endometriosis usually involves serosa and subserosa. When there is deep invasion into the muscularis propria and submucosa, it can be mistaken for colon cancer, delaying and complicating diagnosis. The gold standard for diagnosing endometriosis is laparoscopy, but colonoscopy can provide direct visualization of lesions with the opportunity for EMR and confirmatory biopsy. As rectosigmoid endometriosis surgery is associated with high rates of complication when compared to other parts of the colon, EMR was preferred in our case. Hormone therapy can help prolong the recurrence interval between resection and recurrence, but has no effect on lesion size. A multidisciplinary approach to intestinal endometriomas with hormone therapy combined with EMR can lower recurrence, remove lesions completely, and help patients avoid endometrioma complications and high-risk surgical procedures.Figure 1.: a: Lesion development prior to EMR. b: Cap-assisted underwater technique piecemeal EMR performed using hot 20 mm and 10 mm snares. c: Lesion was completely removed, retrieved, and APC ablation was performed on residual tissue adjacent to the resection site, as well as resection bed.

EMR combined with hybrid argon plasma coagulation to prevent recurrence of large nonpedunculated colorectal polyps (with videos)

EMR is the mainstay of therapy for large colorectal polyps. Local recurrence after EMR is common and can be reduced using margin ablation. Our aim was to evaluate recurrence rates when using hybrid argon plasma coagulation (h-APC) ablation after EMR. Adult patients (aged 18-89 years) undergoing EMR of nonpedunculated colorectal polyps≥20mm were enrolled in a prospective multicenter study. h-APC was used to ablate all defect margins and also the resection surface in selected cases. The primary study outcome was recurrence rates found during the first follow-up colonoscopy. Secondary outcomes were technical success and adverse event rates. EMR with h-APC ablation was used in 101 polyps (84 patients, 46.4% women). EMR with h-APC ablation was technically successful in all cases (median EMR time, 15 minutes; median h-APC ablation time, 4 minutes). Median polyp size was 30mm (range, 20-60). Resected polyps were either adenomas (68/101 [67.3%]), sessile serrated lesions (27/101 [27%]), or adenocarcinomas (6/101 [6%]). The post-EMR recurrence rate was 2.2% (2/91) (95% confidence interval, .27-7.71). All 6 patients with cancer (intramucosal cancer, 4; T1sm cancer, 2) were found to have complete eradication of the primary tumor after EMR with h-APC, and none had lymph node metastasis. Four serious adverse events occurred in 3 patients (2 delayed bleeding [2.4%], 1 abdominal pain [1.2%], and 1 microperforation [1.2%]. All serious adverse events resolved with either endoscopic or antibiotic treatment only. EMR with h-APC showed a high technical success rate, low adverse event rate, and very low post-EMR recurrence rates. (Clinical trial registration number: NCT04015765.).

Cold snare polypectomy vs. hot snare polypectomy vs. argon plasma coagulation for small (5-9mm) left-sided colorectal polyps: a prospective randomized trial.

To compare recurrence rates among three endoscopic treatment modalities for 5-9 mm left-sided colorectal polyps. Consecutive adults referred for elective colonoscopy (1/2015-1/2018) with at least one polyp of eligible size (5-9 mm) located distally to the splenic flexure were randomly assigned (1:1:1) to one of three treatment modalities: (1) cold snare polypectomy (CSP), (2) hot snare polypectomy (HSP) and (3) argon plasma coagulation (APC) ablation (50-60 W, flow: 2 l/min). The polyp site was marked with an endoscopic tattoo, and a follow-up colonoscopy with scar biopsies was performed >6 months after the index procedure. Outcomes were polyp recurrence rate and occurrence of complications. One hundred nineteen patients were enrolled, of whom 112 (62.5% males, mean age 61.1 ± 9.9 years) with 121 polyps (CSP, 39; HSP, 45; APC, 37) returned for follow-up colonoscopy. Mean polyp size was 6.7 ± 0.91 mm, 58% were located in the sigmoid, 33% in the rectum and 8% in the descending colon. The majority of polyps resected by CSP or HSP were neoplastic (tubular adenomas: 25.9%, tubulovillous adenomas: 11.1% and sessile serrate adenomas/polyps: 17.5%). No cases of delayed bleeding or perforation occurred. Scar biopsies at follow-up colonoscopy (performed after a mean interval of 13.4 ± 3.8 months) revealed 7 (5.8%) cases of polyp recurrence, showing no significant difference among the three treatment groups [CSP, 3/39 (7.7%); HSP, 1/45 (2.2%); APC, 2/37 (5.4%); P = 0.51). CSP, HSP and APC-ablation are effective and well-tolerated treatment modalities for 5-9 mm left-sided colorectal polyps. The present randomized study did not detect any difference in polyp recurrence rate among the three endoscopic techniques.

S2557 Endoscopic Treatment of Gastric Perforation Resulting From Slipped Nissen Fundoplication

Introduction: Nissen fundoplication is used to treat gastroesophageal reflux disease and gastric hernias. Herein, we present a rare case of slipped fundoplication induced by physical strain, which was complicated by gastric perforation resulting in a pneumomediastinum and pleural effusion. Due to his herniated stomach, initial esophagram failed to demonstrate the diagnosis. Perforation was closed via endoscopy and resulting empyema was managed with antibiotics and chest tube drainage. Clinical resolution was achieved. Case Description/Methods: A 66 yo male with history of compensated cirrhosis and polycystic kidney disease, who had previously undergone Nissen fundoplication in 1995 for hiatal hernia presented with sudden onset of sharp epigastric pain in association with neck swelling and dyspnea after lifting a heavy wheelbarrow. Vitals were stable. Physical exam was notable for subcutaneous emphysema. Initial laboratory data was only significant for leukocytosis (19 bil/L). CT scan demonstrated pneumomediastinum and collapsed right lung. Initial esophagram showed no extra-luminal contrast leakage, but CT chest performed the following day discovered a contrast collection above the diaphragm suggestive of esophageal perforation. Upper endoscopy findings included a recurrent large hiatal hernia with a small perforation noted near the dome of the fundus. Pustular drainage was seen and contrast injection detected the same fluid collection as noted on imaging. Closure was achieved with argon plasma coagulation ablation and an 11 mm over-the-scope-clip (OTSC) deployed in retroflexed position. Subsequent serial imaging with upper GI series and CT scans confirmed lack of contrast leakage and resolution of pneumomediastinum. Empyema was managed with chest tube drainage and antibiotics. Discussion: We demonstrate a rare case of gastric fundus perforation likely resulting from acute slippage of fundoplication from his initial surgery 26 years ago caused by physical strain. Upon presentation, patient lacked typical peritoneal signs due to recurrent herniation of his stomach above the diaphragm. Thus, instead, patient was found to have mediastinal air and a pleural effusion. Lastly, due to altered anatomy, the esophagram did not detect the perforation, necessitating endoscopic evaluation. With the development of OTSCs, gastroenterologists now can safely and effectively treat gastrointestinal perforations.

Clinical Outcomes following Endoscopic Treatment for Sporadic Nonampullary Duodenal Adenoma

Background and Aims: Endoscopic treatment for duodenal neoplasms is associated with a high risk of perforation. This study aimed to determine the feasibility of endoscopic treatment for sporadic nonampullary duodenal adenoma (SNDA). Methods: Consecutive patients undergoing endoscopic treatment for SNDA between January 2005 and December 2015 were included in the study. Clinical characteristics and endoscopic outcomes were analyzed using medical records. Long-term outcome was assessed in patients whose follow-up period was >12 months >1 year. Results: A total of 95 lesions (92 patients) were treated with argon plasma coagulation (APC) ablation (n = 25), endoscopic mucosal resection (EMR, n = 59), or endoscopic submucosal dissection (ESD, n= 11). The median age was 54.9 years, and 63% were male. In patients who underwent EMR and ESD, the en bloc resection rate was 83.1 and 90.0% (p > 0.99); and the complete resection rate was 81.4 and 80% (p > 0.99), respectively. Perforation occurred in 8 patients (8.7%), 4 of whom required surgery. The ESD group showed a significantly higher perforation rate than APC or EMR group (45.5 vs. 0 and 5.1%; p < 0.001). During the median follow-up period of 19 months (range 12–137 months), one patient in the APC ablation group experienced recurrence; no recurrences were seen among EMR and ESD groups. Conclusions: Favorable long-term outcomes indicate that endoscopic treatment is an effective approach for the treatment of SNDA. Considering the high risk of perforation associated with ESD, APC, or EMR may be an acceptable alternative.

A145 A SUBMUCOSAL FLUID CUSHION PREVENTS MUSCLE LAYER DAMAGE DURING ARGON PLASMA COAGULATION

Abstract Background Thermal damage to the muscle layer of the gastrointestinal wall can occur during mucosal application of argon plasma coagulation (APC). This injury may be mitigated by creating a fluid cushion within the submucosal layer that physically separates the mucosa from the muscle layer and suppresses unwanted tissue temperature elevation. This in turn protects the muscle layer from thermal damage. The coagulative threshold of muscle proteins is known to be about 60°C, but there are no published systematic assessments of the minimum injection volume needed nor the ideal injectate to prevent thermal damage to the muscle layer during mucosal APC ablation. Aims Our aims were, firstly, to measure the final temperature inside the fluid cushion after mucosal ablation with APC and then to determine any differences in the final temperature between various injectable solutions. Secondly, we sought to determine the minimum volume of injectate required to protect the muscle layer from thermal damage. Methods All experiments were performed in an ex-vivo porcine gastrointestinal tract model. Five different fluids (normal saline, Glyceol, Gelafundin, Voluven and Eleview) of different volumes (range 0 - 5mL) were injected into the submucosa of the esophagus, stomach (fundus) and rectum to create a fluid cushion. APC was applied to the mucosa for a fixed duration (3s) at different power settings (ranging from 30 - 120W). Immediately after APC treatment, the final temperature was measured by placing a contact thermometer inside the fluid cushion, just on top of the muscle layer. Results There was no significant difference in the temperature measured at the surface of the muscle layer between elevation with normal saline, Glyceol, Gelafundin, Voluven and Eleview at all 3 tissue locations at equal injection volumes and power settings. The experiments showed that the temperature rose for each injectate with heightened power settings but also decreased with increasing volume of injected fluid. The minimum amount of fluid needed to protect the muscle layer from thermal damage was 2mL for the esophagus, stomach and rectum in the case of a power setting between 30 to 90W and 3mL in the case of 90 to 120W. Conclusions Normal saline and four commercially available submucosal injectates possess similar thermoregulatory effects as an insulator of the muscle layer during APC treatment. As opposed to the choice of injectate or anatomic location treated, the volume of fluid injected is the main determinant of the final temperature at the level of the muscularis propria. To reduce the likelihood of thermal damage to deeper layers of the GI tract when APC is applied, a minimum injection volume of 2mL is recommended if &amp;lt;90W of power is utilized. Funding Agencies None

Bronchoscopic management of haemoptysis due to endobronchial metastasis of papillary thyroid carcinoma

Metastatic involvement of lung by thyroid cancer is common, although presentation with endobronchial disease is rarely encountered. When it occurs, threats to airway patency by luminal obstruction and haemoptysis may occur, requiring prompt recognition and intervention to avoid hypoxia and asphyxiation. Bronchoscopic evaluation is essential for both diagnosis and intervention. To our knowledge, we describe the first case of endobronchial papillary thyroid carcinoma elucidated using bronchoscopic biopsy followed by definitive management using argon plasma coagulation (APC) ablation.

2118 A Challenging Case of Recurrent Rectal Adenoma Despite Multiple Endoscopic Mucosal Resections (EMRs) and Trans-Anal Endoscopic Microsurgeries (TEMS)

INTRODUCTION: Detection and complete removal of colorectal adenomas is essential in reducing the incidence and mortality of cancer. Advanced rectal adenomas can be removed by a number of techniques including Endoscopic Mucosal Resection (EMR), Endoscopic Submucosal Dissection (ESD) and Trans-anal Endoscopic Microsurgery (TEMS). Despite complete resection, local recurrence remains a challenge in some patients. We report a rare case of a recurrent rectal adenoma despite multiple EMRs and TEMS procedures over a 5-year period. CASE DESCRIPTION/METHODS: A 63-year female was referred for EMR of a 2 cm rectal adenoma found on screening colonoscopy 5 years ago (Figure 1). Colonoscopy with en-bloc EMR was done without difficulty. On 6-month follow-up a recurrent adenoma was seen at EMR site. En-bloc EMR was again performed followed by argon plasma coagulation (APC) ablation of edges. Follow-up flexible sigmoidoscopy 6-months later again showed a recurrent adenoma. Patient was referred for TEMS; full-thickness resection was performed with negative margins on pathology specimen. Surveillance colonoscopy 6 months after TEMS revealed recurrent adenoma at the TEMS site. TEMS was repeated. Follow-up endoscopic examination and biopsy 2 months and 1 year after the second TEMS revealed no evidence of lesion recurrence (Figure 2). However her most recent colonoscopy, 3 years after the second TEMS, showed a recurrent 6 mm sessile adenoma at same site (Figure 3). After multidisciplinary consultation, she is scheduled to undergo a third TEMS procedure. DISCUSSION: The reported incidence of recurrent rectal adenoma is 4-11%. Factors affecting local recurrence include size of index polyp and completeness of resection. Despite complete resection, some patients will develop repeated recurrence. Ramkumar et al. reported 669 patients who underwent TEMS for treatment of rectal lesions; 15 pts required 3 or more TEMS procedures. Repeat TEMS was shown to be safe with similar postoperative complications and similar rates of margin clearance (81% vs 88%, P = 0.09) compared to primary TEMS 1 . In our patient, a rectal adenoma recurred despite 2 en-bloc EMRs and 2 TEMS. This demonstrates the need for close surveillance and the importance of a multi-disciplinary treatment approach in these patients.

Nitrous oxide cryotherapy ablation for refractory gastric antral vascular ectasia.

Argon plasma coagulation (APC) is typically the first-line therapy for gastric antral vascular ectasia (GAVE). However, many patients are refractory to APC ablation. We examined the safety and efficacy of nitrous oxide CryoBalloon cryotherapy ablation for GAVE refractory to APC. This is a retrospective review of patients with refractory GAVE treated with the CryoBalloon system. Technical success was defined as successful ablation of the visualized GAVE. Clinical success was defined by transfusion independence and percentage of GAVE that was eradicated. Twenty-three patients with GAVE were included, of whom 16 patients (70%) had two treatments with the CryoBalloon and seven patients (30%) had one treatment. Technical success was achieved in all patients. At six months, 19/23 (83%) were transfusion independent, while 20/23 (87%) had more than 75% of the GAVE eradicated. Patients were transfused an average of 1.8 units/month one year prior to cryotherapy and an average of 0.3 units/month up to six months post-cryotherapy (p < 0.001). The average increase in mean hemoglobin at six months was 2.55 g/dl. No acute or late adverse events were reported. CryoBalloon ablation is an efficacious and safe modality for the treatment of GAVE. Prospective studies need to be conducted to determine comparative results to standard therapies.

Efficacy, Tolerance, and Safety of Hybrid Argon Plasma Coagulation for the Treatment of Barrett’s Esophagus: A U.S. Pilot Study

Introduction: A novel technique for Barrett’s esophagus (BE) ablation, termed hybrid argon plasma coagulation (APC), has recently been developed. This technique raises mucosa using a high-pressure water jet to achieve needleless submucosal injection. Hybrid ablation may reduce injury to the underlying submucosa, potentially decreasing rates of stricture formation and pain. Current literature on this method is limited. The aims of this pilot study were to evaluate the efficacy, tolerance and safety of Hybrid-APC for the treatment of BE. Methods: Patients with biopsy proven BE referred to our tertiary care center for mucosal ablation were recruited. Both treatment-naive and patients previously treated were included. Ablation was performed by 2 endoscopists using a standardized technique as follows: after APC marking of the Barrett’s segment, submucosal injection was performed followed by a first pass of APC ablation. Areas of coagulated tissue were then debrided using a distal attachment cap. Repeat submucosal injection followed by second pass ablation was then performed at a lower setting. Efficacy of ablation was measured on follow up endoscopy via reduced size of visible BE or biopsy-proven complete resolution of intestinal metaplasia (CRIM). Tolerance and safety were evaluated with patient calls on post-procedure days (PPD) 1 and 7. Results: A total of 25 patients underwent 38 HAPC treatments. Baseline characteristics included nondysplastic 76%, Indeterminate for dysplasia 12%, Low Grade Dysplasia 8%, High Grade Dysplasia 4% with average age of 68.0 years, 76% males, Prague C range of 0-6, and Prague M range of 0-8. History of previous treatments included RFA (44%), EMR (20%), cryotherapy (12%). 44% were treatment-naive. Average procedure time was 25 minutes. 16 of 25 patients (64%) underwent follow up endoscopy; all had endoscopic improvement of BE with a reduced average BE length (initial: Prague C=0.7, M=2.1; followup: Prague C=0.26, M=0.6; P=0.002). 9 out of 16 patients (56.3%) achieved CRIM. 6 patients (37.5%) reached CRIM after one hybrid APC treatment. Average pain scores (0 to 10 scale) was 3 on PPD 1 and 0.71 on PPD 7. The only complication was one treatment-related stricture which required a single balloon dilation (stricture rate 4.2%). Conclusion: Based on this pilot study, hybrid APC appears promising in the treatment of BE with a tolerability and a safety profile similar to radiofrequency ablation. These results warrant further study in a large multicenter trial.371_A Figure 1. Initial marking of target area371_B Figure 2. Complete ablation of Barrett’s esophagus tissue with APC following submucosal lift371_C Figure 3. Three-month followup EGD demonstrating resolution of Barrett’s esophagus, and no evidence of stricture formation.

Comparison of the efficacy of four endobronchial ablation techniques in dogs.

The present study aimed to evaluate the safety and efficacy of four commonly used ablation techniques, namely neodymium-doped yttrium aluminium garnet (Nd:YAG) laser therapy, argon plasma coagulation (APC), high-frequency electrocautery and CO2 cryotherapy. The techniques were performed at various powers or impedance settings, and for various durations, on the trachea of beagle dogs. Pathological changes of the tracheal wall were assessed by bronchoscopy. The endoscopic gross appearance of lesions induced by ablation treatments was consistent with the histopathological changes. The results suggested that cryotherapy was relatively safe, whereas APC induced superficial tissue coagulative necrosis. Furthermore, Nd:YAG laser therapy was the most efficient technique and showed the greatest penetration potential. In general, tissue injury was exacerbated with extended application time, at constant power or impedance. The safest application parameters were 20 W for ≤1 sec for Nd:YAG laser therapy, 40 W for ≤3 sec for electrocautery, 40 W for ≤5 sec for APC and 100 Ω for ≤120 sec for cryotherapy. At the maximum times, these settings resulted in identical pathological changes. Healing of the lesions following ablation was achieved within 3 weeks. The Nd:YAG laser, APC, electrocautery and cryotherapy endobronchial ablation techniques differed according to their potential and limitations for application on the trachea. However, when applied at specific combinations of power or impedance and duration, they exhibited similar efficacies.

Tu1732 The Usefulness of Argon Plasma Coagulation Ablation Subsequent to Endoscopic SNARE Papillectomy for Ampulla Adenoma

Tu1732 The Usefulness of Argon Plasma Coagulation Ablation Subsequent to Endoscopic SNARE Papillectomy for Ampulla Adenoma

Nonampullary duodenal adenoma: Current understanding of its diagnosis, pathogenesis, and clinical management.

Nonampullary duodenal adenomas are relatively common in familial adenomatous polyposis (FAP), but nonampullary sporadic duodenal adenomas (SDAs) are rare. Emerging evidence shows that duodenal adenomas, regardless of their anatomic location and whether they are sporadic or FAP-related, share morphologic and molecular features with colorectal adenomas. The available data suggest that duodenal adenomas develop to duodenal adenocarcinomas via similar mechanisms. The optimal approach for management of duodenal adenomas remains to be determined. The techniques for endoscopic resection of duodenal adenoma include snare polypectomy, endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and argon plasma coagulation ablation. EMR may facilitate removal of large duodenal polyps. Although several studies have reported cases of successful ESD for duodenal adenomas, the procedure is technically difficult to perform safely because of the anatomical properties of the duodenum. Although current clinical practice recommends endoscopic resection of all large duodenal adenomas in patients with FAP, endoscopic treatment is usually insufficient to guarantee a polyp-free duodenum. Surgery is indicated for FAP patients with severe polyposis or nonampullary SDAs or FAP-related polyps not amenable to endoscopic resection. Further studies are needed to develop newer endoscopic techniques to guide diagnostic and therapeutic decisions for future management of nonampullary duodenal adenomas.

Endoscopic Management of a Gastrocolonic Fistula: A Rare Esophageal Stent Adverse Event

FigureIntroduction: A 55 year old man presented for second opinion for management of his esophageal cancer. His initial presentation was a year earlier with severe dysphagia and he was found to have esophageal adenocarcinoma with liver metastasis. He was treated with chemotherapy and underwent esophageal stent placement. He was admitted a month later with sepsis and stent migration. His stent was removed and he was eventually discharged home but started having diarrhea and became severely malnourished. He was treated with total parentral nutritional and underwent a surgical J-tube placement. He however continued to have severe diarrhea with no clear etiology so hospice was recommended. He presented to our center for a second opinion. An EGD was performed showing a gastrocolonic fistula. Given his advanced cancers and severe malnutrition, he was not a surgical candidate and was dependent on total parentral nutrition (TPN). He was offered endsoocpic repair. Methods: Repair was performed with Argon plasma coagulation ablation of the mucosa in the fistula track and multilayer closure. Closure consisted of endoscopic suturing consisting of a layer of running sutures and a second layer of interrupted suture to decrease the tension from the first layer. The colonic side was then closed with an over the scope clip placed from the colonic end. A repeat endoscopy in one week showed a small residual fistula which was again sutured and reinforced with an over the scope clip. Results: The fistula resolved. The patient gained 20 Kg in 3 months and TPN was discontinued. His diarrhea resolved. His repeat imaging and upper endoscopy 4 months later were consistent with continued closure of the fistula. He was able to resume systemic therapy for his stage 4 cancer. He initially responded to treatment. 7 months later his disease progressed including an increase in the esophageal mass and gastric wall infiltration with tumor. He became debilitated and his fistula recurred. Plans were made to attempt repair again however the patient developed urosepsis and became more debilitated and was referred to hospice. Conclusion: Gastrocolonic fistula is a rare adverse event of esophageal stenting. Endoscopic repair allowed healing of the fistula with subsequent 20 Kg weight gain, discontinuation of intravenous nutrition support and resumption of systemic chemotherapy. This minimally invasive procedure improved the patient nutritional status and quality of life until he succumbed to his disease.

The different effects of cryoablation and thermal ablation on inflammation and scar hyperplasia in rat skin

To compare the impact of different methods of ablation, i.e. cryotherapy,argon plasma coagulation (APC) and radiofrequency, when applied to the skin of rats, on the systemic inflammatory response and local tissue damage. Forty-eight healthy male SD rats were randomly divided into 4 groups: cryotherapy, APC, radiofrequency, and sham procedure. Cryotherapy, APC and catheter ablation were applied to the skin of the rats in the 3 groups respectively, while the sham-operated animals underwent shaving only. The animals were assessed after 1,3,5,7, and 28 days. The serum level of TNF-α was measured. TGF-β1 positive cells in the skin and the thickness of the scar tissue were assessed at the corresponding times, while HE-stained sections collected on the 5th day were examined. When the levels of serum TNF-α were compared after 24h, there were no significant differences among the cryotherapy, APC, and radiofrequency groups(cryotherapy and APC, cryotherapy and radiofrequency, APC and radiofrequency, t values were 0.23, 0.22, and 1.53, respectively, all P>0.05), but the levels in each of these 3 groups were significantly higher than that in the sham-operated group ( t values were -4.83, -4.63, and -3.24, respectively, all P<0.05). When the levels of TNF-α were compared after 7d, the cryotherapy group showed the highest (146 ± 8 ng/L), significantly higher than that in the sham-operated group (t value 3.88, P<0.05). The multiplication values of the average optical density and TGF-β1 positive cells in the rat skin among the radiofrequency (105.3 ± 16.4), APC(58.8 ± 12.8), and cryotherapy (36.4 ± 2.8) groups were significantly different (all P<0.05). The difference was also significant between the APC and the radiofrequency groups compared to the sham operation (34.1 ± 1.7) group (t values were 6.02 and 8.81, respectively, both P<0.05). HE staining of sections of the rat skin after 5 days showed that, radiofrequency resulted in the most serious injury to the skin, while the damage resulting from APC and cryotherapy varied, but was not significantly different (t value 0.91, P>0.05). The radiofrequency group showed the highest value (612 ± 98 µm) in the thickness of the scar tissue on the skin, which was significantly higher than that of the APC group (362 ± 120 µm, t value 4.54, P<0.05), while there was no scar formation in response to cryotherapy or sham operation. Cryotherapy, APC and radiofrequency, when applied locally to the skin, caused different types of injury and had different effects on inflammation. The response of inflammation varied with different processing methods. Cryotherapy resulted in significantly lower response compared to either radiofrequency or APC when the inflammatory response was assessed after 5 days and the scar formation after 28 days.

Sa1540 Long-Term Outcomes and Prognostic Factors for Local Recurrence After Argon Plasma Coagulation Ablation for Gastric Adenoma With Low Grade Dysplasia on an Outpatient Basis

Argon plasma coagulation (APC) ablation has been attempted as a considerable treatment option for many gastrointestinal tract diseases. For the treatment of gastric adenoma (GA) with low grade dysplasia (LGD), APC ablation seems to be easier and safer than other endoscopic treatment modalities such as EMR or ESD. The purpose of this study was to evaluate the adverse event, long-term outcomes and prognostic factors for local recurrence after APC ablation for GA with LGD on an outpatient basis.

Portal Hypertensive Polyposis: A Consequence of Esophageal Variceal Ligation?

A 59-year-old man with history of nonalcoholic steatohepatitis (NASH) cirrhosis and portal hypertension with previous esophageal variceal ligation presented with 2 days of melena and fatigue. He was taking 20 mg of propranolol 3 times per day. Hemoglobin was 7 g/dL and platelets were 59,000/L. Esophagogogastroduodenostomy (EGD) performed 1 year earlier revealed large distal esophageal varices requiring ligation with 5 bands and gastritis located in the antrum. EGD during this admission revealed small distal esophageal varices, as well as 3 large polyps and many small polyps in the distal body and antrum (Figures 1 and 2). The large polyps were resected via hot snare polypectomy (Figure 3). Two hemoclips were applied to 1 polypectomy site and argon plasma coagulation ablation was performed for the base of the largest polyp. Histopathologic examination of the polyps revealed hyperplastic-like gastric polyps with marked foveolar hyperplasia with cystic dilations, edematous and fibrotic stroma, a prominent capillary proliferation in the lamina propria, and scattered telangiectactic vessels, consistent with portal hypertensive polyposis (PHP).