Min Tae Kim

Fluoroscopic Gastroduodenal Stent Placement in 55 Patients with Endoscopic Stent Placement Failure

PurposeTo evaluate the technical feasibility and clinical effectiveness of fluoroscopic self-expandable metal stent (SEMS) placement in malignant gastroduodenal obstructions after failed endoscopic SEMS placement.Materials and MethodsBetween September 2010 and July 2017, 874 patients underwent endoscopic SEMS placement for dysphagia caused by malignant gastroduodenal obstructions. Endoscopic SEMS placement failed in 55 of 874 patients (6.3%). These patients were referred for fluoroscopic SEMS placement. In case of failed fluoroscopic SEMS placement, combined endoscopic and fluoroscopic SEMS placement was attempted at the same setting.ResultsFluoroscopic SEMS placement was technically successful in 40 of 55 patients (72.7%). Combined endoscopic and fluoroscopic SEMS placement was technically successful in 6 of 15 patients with fluoroscopic SEMS placement failure. Failures in the nine patients were due to complete obstruction (n = 5) and acute angulation at the stricture site (n = 4). The overall technical success rate was 83.6% (46/55). Clinical success was achieved in 95.6% of patients (44/46). Complications occurred in 7 of 46 patients (15.2%), including tumor overgrowth (n = 3), SEMS migration (n = 3), and bleeding (n = 1). The median SEMS patency and patient survival periods were 515 (95% confidence interval (CI), 266.6–761.5) and 83 (95% CI 60.6–105.4) days, respectively.ConclusionsFluoroscopic SEMS placement is technically feasible and clinically effective in cases of endoscopic SEMS placement failure. A combined endoscopic and fluoroscopic approach increases the technical success rate after failure of the endoscopic or fluoroscopic approach.Level of EvidenceLevel IV.

Radiation-induced esophageal strictures treated with fluoroscopic balloon dilation: clinical outcomes and factors influencing recurrence in 62 patients:

Background Balloon dilation is safe and effective for the treatment of radiation-induced esophageal stricture (RIES), with favorable short-term and mid-term outcomes; however, few reports of long-term outcomes exist. Few studies have evaluated factors associated with recurrence after balloon dilation. Purpose To evaluate the long-term outcome of balloon dilation in patients with RIES and to identify factors associated with stricture recurrence. Material and Methods The medical records of 62 consecutive patients who had undergone fluoroscopic balloon dilation for RIES at our institution between December 1998 and June 2016 were reviewed. Results One hundred and twenty balloon dilation sessions were performed in 62 patients (mean = 1.9 sessions per patient). Clinical success was achieved in 53 (86%) patients after single (n = 37) or multiple (n = 16) dilation sessions. Complications occurred in 27% of the dilation sessions. The primary patency rates at one, two, three, and five years were 60%, 56%, 52%, and 52%, respectively. Secondary patency rates at one, two, three, and five years were 87%, 85%, 85%, and 80%, respectively. Multivariate logistic regression analysis identified an interval from radiation therapy (RT) to stricture of ≥6 months (hazard ratio [HR] = 0.205; P < 0.001), strictures located at the cervical esophagus (HR = 5.846; P < 0.001), and stricture length of ≥2 cm (HR = 2.923; P = 0.006) as significant predictors of recurrence. Conclusion Despite the high incidence of ruptures and recurrences, fluoroscopic balloon dilation is valuable as an initial therapeutic option for patients with RIES.

EW-7197, an oral transforming growth factor β type I receptor kinase inhibitor, for preventing peritoneal adhesion formation in a rat model

Background EW‐7197 is an oral transforming growth factor &bgr; type I receptor kinase inhibitor currently undergoing phase I clinical trials for cancer treatment in the United States. This study evaluates whether EW‐7197 prevents peritoneal adhesion formation in a rat model. Methods Forty‐eight female Wistar rats underwent peritoneal adhesion induction by the creation of peritoneal ischemic buttons and were randomly divided into 4 groups of 12 each. The control group received 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction. The 10 mg and 20 mg groups received 10 or 20 mg/kg EW‐7197 phosphate dissolved in 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction. The rebound group received 20 mg/kg EW‐7197 phosphate dissolved in 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction followed by 0.3 mL vehicle only by gavage once daily for an additional 21 days. After the respective treatments were completed, the animals were euthanized. Results All rats survived until the end of the study without complications. EW‐7197 reduced the incidence, quality, and tenacity of peritoneal adhesions in a dose‐dependent manner. Fibrosis and collagen production were reduced in EW‐7197–treated peritoneal ischemic buttons. Transforming growth factor &bgr;/Smad2/3 signaling and mesothelial‐to‐mesenchymal transition were inhibited in EW‐7197–treated peritoneal ischemic buttons. Discontinuation of EW‐7197 was not associated with rebound effects. Conclusion EW‐7197 prevented peritoneal adhesion formation potentially via inhibition of transforming growth factor &bgr;1/Smad2/3–induced mesothelial‐to‐mesenchymal transition in a rat model.

Sirolimus-eluting Biodegradable Poly-l-Lactic Acid Stent to Suppress Granulation Tissue Formation in the Rat Urethra

Purpose To investigate the use of sirolimus-eluting biodegradable stents (SEBSs) to suppress granulation tissue formation after stent placement in a rat urethral model. Materials and Methods All experiments were approved by the animal research committee. A total of 36 male Sprague-Dawley rats were randomized into three equal groups after biodegradable stent placement. Group A received control biodegradable stents. Groups B and C received stents coated with 90 µg/cm2 and 450 µg/cm2 sirolimus, respectively. Six rats in each group were sacrificed after 4 weeks; the remaining rats were sacrificed after 12 weeks. The therapeutic effectiveness of SEBSs was assessed by comparing the results of retrograde urethrography and histologic examination. Analysis of variance with post hoc comparisons was used to evaluate statistical differences. Results SEBS placement was technically successful in all rats. Urethrographic and histologic examinations revealed significantly less granulation tissue formation at both time points in the rats receiving SEBSs (groups B and C) compared with those that received control stents (group A) (P < .05 for all). There were no significant differences in urethrographic and histologic findings between groups B and C (P > .05 for all). However, the mean number of epithelial layers in group B was higher than that in group C at 4 weeks after stent placement (P < .001). Apoptosis increased in group C compared with groups A and B (P < .05 for all). Conclusion The use of SEBSs suppressed granulation tissue formation secondary to stent placement in a rat urethral model; local therapy with SEBSs may be used to decrease stent-related granulation tissue formation.

EW-7197 eluting nano-fiber covered self-expandable metallic stent to prevent granulation tissue formation in a canine urethral model

Purpose To evaluate an EW-7197-eluting nanofiber-covered stent (NFCS) for suppressing granulation tissue formation after stent placement in a canine urethral model. Materials and methods All experiments were approved by the committee of animal research. A total of 12 NFCSs were placed in the proximal and distal urethras of six dogs. Dogs were divided into two groups with 3 dogs each. The control stent (CS) group received NFCSs and the drug stent (DS) group received EW-7197 (1000 μg)-eluting NFCSs. All dogs were sacrificed 8 weeks after stent placement Histologic findings of the stented urethra were compared using the Mann-Whitney U test. Results Stent placement was technically successful in all dogs without procedure-related complications. On urethrographic analysis, the mean luminal diameter was significantly larger in the DS group than in the CS group at 4 and 8 weeks after stent placement (all p < 0.001). On histological examination, mean thicknesses of the papillary projection, thickness of submucosal fibrosis, number of epithelial layers, and degree of collagen deposition were significantly lower in the DS group than in the CS group (all p < 0.001), whereas the mean degree of inflammatory cell infiltration was not significantly different (p > 0.05). Conclusion The EW-7197-eluting NFCS is effective and safe for suppressing granulation tissue formation after stent placement in a canine urethral model.

In Vivo Fluorescence Microendoscopic Monitoring of Stent-Induced Fibroblast Cell Proliferation in an Esophageal Mouse Model

PURPOSE To evaluate the feasibility of self-expanding metal stent (SEMS) placement and fluorescence microendoscopic monitoring for determination of fibroblast cell proliferation after stent placement in an esophageal mouse model. MATERIALS AND METHODS Twenty fibroblast-specific protein (FSP)-1 green fluorescent protein (GFP) transgenic mice were analyzed. Ten mice (Group A) underwent SEMS placement, and fluoroscopic and fluorescence microendoscopic images were obtained biweekly until 8 weeks thereafter. Ten healthy mice (Group B) were used for control esophageal values. RESULTS SEMS placement was technically successful in all mice. The relative average number of fibroblast GFP cells and the intensities of GFP signals in Group A were significantly higher than in Group B after stent placement. The proliferative cellular response, including granulation tissue, epithelial layer, submucosal fibrosis, and connective tissue, was increased in Group A. FSP-1-positive cells were more prominent in Group A than in Group B. CONCLUSIONS SEMS placement was feasible and safe in an esophageal mouse model, and proliferative cellular response caused by fibroblast cell proliferation after stent placement was longitudinally monitored using a noninvasive fluorescence microendoscopic technique. The results have implications for the understanding of proliferative cellular response after stent placement in real-life patients and provide initial insights into new clinical therapeutic strategies for restenosis.

Fluoroscopic subtraction Eustachian tubography: initial feasibility test in a cadaver model

ObjectivesTo evaluate the technical feasibility of direct Eustachian tube catheterisation and subtraction Eustachian tubography in a cadaver model.MethodsA total of 12 separate sessions were performed on both sides of the Eustachian tube (ET) in six human cadavers. Cadavers were positioned for the submentovertical view on a fluoroscopy table. Endoscopy-guided ET selection was used in the first three cadavers, whereas fluoroscopy-guided ET selection was used in the remaining three. Eustachian tubography was performed by injecting 2 ml of contrast media through a 5-Fr catheter. We recorded the success of ET selection, number of attempts, procedure time, and tubography quality using native and subtraction images (range, 0–3).ResultsBoth endoscopy- and fluoroscopy-guided selections were successfully performed in five of six sessions (83.3%). There were no statistically significant differences between the endoscopy- and fluoroscopy-guided procedures in terms of the number of attempts, procedure time, rate of immediate contrast leak to the middle ear cavity, and quality of tubography (p > 0.05). An excellent quality of tubography was obtained in 83.3% (10 of 12 sessions) of subtraction images and in 33.3% (4 of 12 sessions) of native images. The tubography quality score was significantly higher for the subtraction images than for the native images (p = 0.04).ConclusionSubtraction Eustachian tubography using direct catheterisation seems to be technically feasible. The entire ET can be well visualised; thus, this technique can be used as a simple tool for assessment of ET function and anatomy.Key Points• Direct catheterisation of the Eustachian tube is technically feasible.• The entire Eustachian tube could be well visualised by direct Eustachian tubography.• Subtraction Eustachian tubography images have better image quality than native images.• Subtraction Eustachian tubography can provide objective assessment of ET function and anatomy.

Fluoroscopic Balloon Dilation for Treating Postoperative Nonanastomotic Strictures in the Proximal Small Bowel: A 15-Year Single-Institution Experience

PURPOSE To evaluate safety and effectiveness of fluoroscopic balloon dilation (FBD) for treating postoperative nonanastomotic strictures in proximal small bowel. MATERIALS AND METHODS Data of 44 patients (26 men and 18 women; mean age, 53.7 y ± 13.0) treated with FBD for postoperative nonanastomotic strictures in the proximal small bowel between January 2000 and February 2016 were retrospectively reviewed. Site of stricture was located in the first portion of duodenum in 8 (18.2%) patients, second portion of duodenum in 8 (18.2%) patients, third portion of duodenum in 1 (2.3%) patient, fourth portion of duodenum in 1 (2.3%) patient, and proximal jejunum in 26 (59.1%) patients. Mean distance between the most anal-side lesion and the oral cavity was 63.9 cm ± 15.0. RESULTS Technical success was achieved in 39 (88.6%) patients. Mean stricture length was 3.0 cm ± 1.8. Technical failure because of inability to negotiate the guide wire through the stricture occurred in 5 (13.6%) patients. Complete resolution of obstructive symptoms and resumption of oral intake of soft or solid food within 3 days occurred in 34 patients after 1 (n = 32) or 2 (n = 2) FBD sessions, rendering a clinical success rate of 87.2%. There were no major complications directly related to FBD. Median follow-up period was 1,406 days (interquartile range, 594-2,236 d). Nine (26.5%) patients had recurrence within a median 47 days (interquartile range, 20-212 d). CONCLUSIONS FBD may be safe and effective for treating postoperative nonanastomotic strictures in the proximal small bowel.

Respiratory support with venovenous extracorporeal membrane oxygenation during stent placement for the palliation of critical airway obstruction: case series analysis

BACKGROUND Venovenous extracorporeal membrane oxygenation (VV ECMO) is used to support gas transfer of patients suffering from respiratory failure during various procedures. The purpose of this study was to evaluate the technical feasibility and safety of fluoroscopic stent placement under respiratory support with VV ECMO in patients with critical airway obstructions. METHODS We reviewed the records of 17 patients (14 male and 3 female; mean age: 63 years; range, 30-82 years) who underwent self-expandable metallic stent (SEMS) placement under VV ECMO respiratory support for critical airway obstruction caused by malignant (n=16) or benign (n=1) etiology. RESULTS Fluoroscopic placement of SEMS was successful in all patients (100%) with no procedure-related complications. During a mean follow-up of 83 days (range, 10-367 days), 15 (88.2%) of 17 patients showed improvement of Hugh-Jones grades (from 4.7±0.4 to 3.1±0.9, P<0.001). Removal of the endotracheal tube was possible in 11 (84.6%) of 13 patients. Weaning off ECMO was successful in all patients. The ECMO-related and stent-related complication rates were 11.7% (n=2) and 29.4% (n=5), respectively, all successfully managed by additional interventions. Indications for VV ECMO included failure of mechanical ventilation in 13 (76.5%) patients, and orthopnea in 4 (23.5%) patients. CONCLUSIONS Fluoroscopic stent placement under VV ECMO respiratory support can be successfully performed in patients with critical airway obstruction, especially in cases of respiratory distress despite ventilation support and an inability to lie in a supine position. However, further studies will be needed to validate the standardized methods and specific indications.