Effects of argon plasma coagulation on human stomach tissue: An ex vivo study

Injury patterns and potential diagnostic pitfalls associated with radiation and radio-chemotherapy in the stomach and gastroesophageal junction

Chemoradiation-associated injury may cause marked epithelial and stromal changes in gastric specimens. We characterized these histologic features in a retrospective series of cases. Nineteen cases of radiochemotherapy-associated gastropathy were identified, including 16 from our institution and 3 from consultation material. Patient charts and hematoxylin and eosin-stained slides were reviewed. Most patients were men (79%) with a median age of 66 years. All patients had a documented history of radiation and 15 patients also received chemotherapy. The median time from treatment to biopsy or resection was 2.3 months. Gross and endoscopic findings included erythematous, hemorrhagic, or ulcerated mucosa. Mucosal eosinophilia was seen in 16 cases (84%) while 10 cases (53%) featured acute inflammation including neutrophilic microabscesses. Epithelial changes included increased apoptosis (6 cases, 32%) and marked epithelial atypia (10 cases, 53%), potentially mimicking malignancy in some cases. However, the atypical cells featured voluminous eosinophilic cytoplasm with low nuclear-to-cytoplasmic ratio, a clue to their benign nature. Neuroendocrine cell nests were seen in 4 cases (21%) and loosely aggregated in 1 case, potentially mimicking a well-differentiated neuroendocrine tumor or enterochromaffin-like (ECL) cell hyperplasia in autoimmune gastritis. Eleven cases (58%) featured vascular changes that included vessel dilation, hobnailed endothelial cells, and fibrin thrombi. Stromal changes were seen in 11 cases (58%) and included lamina propria hyalinization, submucosal fibrosis, and myofibroblast atypia. Injury associated with radiochemotherapy is histologically varied and may affect epithelial, stromal, and vascular compartments. Familiarity with these features is important as a subset of these findings may provoke concern for neoplasia.

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Objectives and study aims  Recent pilot studies have assessed the feasibility of a novel 1.9-/1.5-μm dual emission endoscopic laser treatment ( _1.9-/1.5-μm DEELT) for endoscopic hemostasis, ablation and resection. In this study, we investigated the safety and efficacy of _1.9-/1.5-μm DEELT in patients with chronic anemia due to gastrointestinal vascular lesions in a real-life multicenter cohort setting.

Patients and methods  Consecutive patients with moderate/severe iron-deficiency anemia undergoing _1.9-/1.5-μm DEELT for upper and lower gastrointestinal bleeding due to vascular lesions were enrolled in three academic referral centers. Safety and successful ablation of vascular lesions were the primary outcomes. Long-term hemoglobin level, blood transfusion requirements, endoscopic severity scores of complex vascular disorders and technical lasing parameters were also assessed. Long-term hemoglobin variations have been further assessed, with repeated measure analysis of variance and univariate analyses.

Results  Fifty patients (median age 74; range 47 to 91 years) with gastric antral vascular ectasia (GAVE) (22), angioectasia (22) and radiation proctopathy (6) underwent 58 _1.9-/1.5-μm DEELT between 2016 and 2020. All procedures were technically feasible leading to successful ablation of the targeted lesion/s, with no incident or adverse event potentially related to the _1.9-/1.5-μm DEELT technique. Within a 6-month follow-up, hemoglobin values significantly rose (+ 1.77 at 1 month and + 1.70 g/dL at 6 months, P  < 0.01), the blood supply requirement decreased (at least one transfusion in 32 versus 13 patients, P  < 0.01), and GAVE lesions showed a clear endoscopic improvement (from 5 points to 1 points, P  < 0.01).

Conclusions  The 1.9-/1.5-μm laser system is a safe and effective endoscopic tool for haemostatic ablation of bleeding vascular lesions within the gastrointestinal tract in tertiary referral centers.

Fluid cushion protects against thermal damage during argon plasma coagulation

Background

Thermal damage to the muscle layer during mucosal application of argon plasma coagulation (APC) may be avoided by creating a fluid cushion within the submucosal layer, but the minimum injection volume needed or the ideal injection fluid are yet to be established. We conducted a systematic ex vivo study with this aim.

Methods

All experiments were performed in an ex vivo porcine gastrointestinal tract model. Five different fluids (saline, Glyceol, Gelafundin, Voluven, and Eleview) of different volumes were injected into the submucosa of different parts of the gastrointestinal tract. APC was applied to the mucosa at different power settings. Immediately after APC treatment, the temperature was measured through a thermocouple placed inside the fluid cushion, just on top of the muscle layer. The minimum volume of fluid needed to protect the muscle layer from thermal damage was determined.

Results

There was no difference in the temperature measured among the different injection fluids at the surface of the muscle, in all the locations, at equal injection volumes and power settings. The minimum amounts of fluid needed to protect the muscle layer were 2 and 3 mL for power settings of 30-90 W and 90-120 W, respectively.

Conclusions

Normal saline and 4 commercially available submucosal injection fluids possess similar thermal protective effects. To reduce the likelihood of thermal damage to deeper layers when APC is applied, a minimum injection volume of 3 mL is recommended if less than 90 W power will be utilized over 3 sec.

Clinical feasibility of a new antireflux ablation therapy on gastroesophageal reflux disease (with video)

BACKGROUNDS AND AIMS

New mucosal resective and ablative endoscopic procedures based on gastric cardiac remodeling to prevent reflux have appeared. We aimed to evaluate the feasibility of a new ablative technique named antireflux ablation therapy (ARAT) for control of GERD in patients without hiatal hernia.

METHODS

Patients with proton pump inhibitor (PPI)-refractory GERD without hiatal hernia underwent ARAT between January 2016 and October 2019. Gastroesophageal Reflux Disease-Health-Related Quality of Life (GERD-HRQL), upper endoscopy, 24-hour pH monitoring, and PPI use were documented at 3, 6, 12, 24, and 36 months after ARAT.

RESULTS

One hundred eight patients were included (61 men [56.5%]; median age, 36.5 years; range, 18-78 years). ARAT was performed on all patients. At the 36-month evaluation, 84 patients had completed the protocol. Median ARAT time was 35.5 minutes (range, 22-51 minutes), and median circumference ablation was 300° (range, 270°-320°). No major adverse events occurred, and 14 of 108 patients (12.9%) presented with stenosis that was responsive to balloon dilation (<5 sessions). At the 3-month evaluation, the acid exposure time (AET), DeMeester score, and GERD-HRQL score had decreased from 18.8% to 2.8% (P = .001), 42.5 to 9.1 (P = .001), and 36.5 to 10 (P = .02), respectively, and these values were maintained up to 36 months. Success (AET <4%) was achieved in 89% and 72.2% at 3 and 36 months, respectively. Related factors at 36 months were as follows: pre-ARAT Hill type II (odds ratio [OR], 3.212; 95% confidence interval [CI], 1.431-5.951; P = .033), post-ARAT 3-month Hill type I (OR, 4.101; 95% CI, 1.812-9.121; P = .042), and AET <4% at 3 months (OR, 5.512; 95% CI, 1.451-7.621; P = .021).

CONCLUSIONS

ARAT is a feasible, safe, and effective therapy for early and mid-term treatment of GERD in patients without a sliding hiatal hernia. However, longer follow-up evaluations and randomized comparative studies are needed to clarify its real role. (Clinical trial registration number: NCT03548298.).

Comparison Between Redo Endoscopic Treatment and Surgery in Patients with Locally Recurrent Gastric Neoplasms

BACKGROUND

Treatment of locally recurrent gastric neoplasms after endoscopic resection remains challenging. We investigated the efficacy and safety of treatment options for recurrent gastric neoplasms localized to the scar of previous endoscopic submucosal dissection (ESD).

METHODS

The clinicopathological characteristics and treatment outcomes of patients who underwent endoscopic treatment or surgery for recurrent gastric neoplasms between June 2010 and May 2017 were retrospectively reviewed.

RESULTS

Of the 92 patients included, 74 underwent endoscopic treatment (51 redo ESD, 23 argon plasma coagulation [APC] ablation) and 18 underwent surgery. The redo ESD procedure time was significantly longer than that of the primary ESD (31.0 versus 22.0 min, p = 0.018). Overall, adverse events occurred in 11 patients (12.0%), with the incidence being significantly higher in the surgery group (27.8% versus 8.1% in the endoscopic treatment group, p = 0.036). Local recurrence-free survival rates were 81.1% for the endoscopic treatment group (86.3% and 69.6% for redo ESD and APC groups, respectively) and 100% for the surgery group (log rank p = 0.033). Logistic regression analysis showed that tumor size > 12.5 mm (odds ratio [OR] 5.14, 95% confidence interval [CI] 1.25-26.9, p = 0.032) and tumors located in the upper two-thirds of the stomach (OR 4.43, 95% CI 1.27-16.8, p = 0.023) were associated with non-curative resection after redo ESD.

CONCLUSIONS

Endoscopic treatment could be an effective and safe alternative to surgery for selected patients with gastric neoplasms recurring at the scar of previous ESD. Especially, patients having small lesions located in the distal part of the stomach could be a good candidate for redo ESD.

Gastric mucosal devitalization (GMD): translation to a novel endoscopic metabolic therapy

Background and study aims  The metabolic effects of bariatric surgery may partially result from removal of the gastric mucosa, an often underappreciated endocrine organ. Using argon plasma coagulation (APC), we may be able to selectively devitalize (ablate) the mucosa. The aim of this study was to identify the optimal tissue color that would correspond to selective gastric mucosal devitalization (GMD) using ex-vivo human stomach specimens. Patients and methods  Stomach specimens were obtained at sleeve gastrectomy. Prior to APC application, a submucosal fluid cushion was created. APC was then applied over a 2 × 2-cm area to the fundus and body, aiming for the three indicator colors (white, golden, brown). Pathological analysis was then performed independently and in a blinded fashion by two pathologists to determine the depth of mucosal and submucosal percent thermal injury and mucosal percent cell death. Results  Six patients were enrolled. There was a significant correlation between tissue color and mucosal percent thermal injury. The highest percent mucosal thermal injury was seen with brown (99.6 %, 95 % CI: 98.7, 100), followed by golden (92.5 %, 95 % CI: 85.5, 99.5), and then white (75.2 %, 95 % CI: 58.3, 92.1, P  < 0.01). Submucosal thermal injury was seen in 88.9 % of the slides. Greater than minimal submucosal injury (> 10 % depth) was found significantly more with brown tissue color (91.6 %) than golden (75 %) or white (33.3 %, P  < 0.05). However, 91.7 % of the entire sample set < 50 % injury. Conclusion  GMD is achievable using APC without thermal injury to muscularis propria. A golden color results in sufficient mucosal injury with only superficial injury to the submucosa.

Electrosurgical and Laser Therapy Tools for the Treatment of Malignant Central Airway Obstructions

Central airway obstruction (CAO) is associated with significant morbidity and increased mortality. Bronchoscopic electrosurgical and laser ablative tools have proven to be safe and effective instruments for the treatment of malignant CAO. Although therapeutic modalities such as electrocautery, argon plasma coagulation, and laser have been used for decades, additional tools including radiofrequency ablation catheters continue to be developed for the treatment of CAO. These modalities are considered safe in the hands of experienced operators, although serious complications can occur. This review describes various electrosurgical and laser therapy tools used for the treatment of malignant CAO along with the specific advantages and disadvantages of each device.

Histological findings after argon plasma coagulation: an ex-vivo study revealing a possible role in superficial ablative treatment of the skin

Argon plasma coagulation (APC) is an electrosurgical technique which can be used to ablate skin lesions with limited invasion depth into dermal tissue. Hence, APC might be well suited for the removal of epithelial tumours. However, there are no data on the effects of APC on human skin tissue. Thus, the aim of this study was to determine the extent of epidermal and dermal damage after APC of human skin. We performed APC ex-vivo on 91 freshly resected human skin samples, which were obtained after reconstructive surgical closures in actinically damaged areas. Tissue effects were evaluated histologically and compared across different power settings. Using 15, 30, and 45 W, median (interquartile range; IQR) coagulation depths were 110.0 µm (91.7-130.0), 113.3 µm (85.8-135.0), and 130.0 µm (100.0-153.3.0), respectively. Median (IQR) thickness of necrosis zone was 30.0 µm (23.3-40.0) at 15 W, 26.7 µm (20.0-41.6) at 30 W, and 43.3 µm (30.8-57.5) at 45 W. The Kruskal-Wallis test showed significant differences between 15 and 30 W versus 45 W for coagulation depth (P = 0.0414), necrosis zone (P = 0.0017), and necrosis according to overlaying epidermal thickness (P = 0.0467). In summary, APC is a simple and controllable electrosurgical technique to remove epidermal tissue with limited penetration to the dermis. Thus, APC is particularly suited for the ablation of epithelial skin lesions and, therefore, may serve as possible treatment approach for intraepithelial neoplasms such as actinic keratosis.