Biomedical subjects

David S Utley

Publications and source records attributed to David S Utley.

5 recordsLinked to original sources

PubMed2004

Complete ablation of esophageal epithelium with a balloon-based bipolar electrode: a phased evaluation in the porcine and in the human esophagus.

BACKGROUND: The aim of this study was to evaluate the endoscopic and the histologic effects of a balloon-based bipolar radiofrequency electrode for ablation of porcine and human esophageal epithelium. METHODS: All procedures were performed with a balloon-based, bipolar radiofrequency system that creates a circumferential, thin-layer epithelial ablation zone within the esophagus. In Phase I, multiple ablations were created in 10 farm swine, followed by acute euthanasia and histologic assessment for completeness of epithelial removal and ablation depth. In Phase II, multiple ablations were created in 19 farm swine, with varying power and energy density, followed by endoscopy at 2 and 4 weeks to assess stricture formation. In Phase III, 3 ablations were created in 12 farm swine, with varying energy density (5, 8, 10, 12, 15, or 20 J/cm 2 ) at 350 W. Animals were euthanized at 48 hours. Histologic examination determined the percentage of epithelium removed and the ablation depth. In Phase IV, 3 patients underwent esophageal epithelial ablation before esophagectomy, creating separate lesions proximal to the tumor. Completeness of epithelial ablation and ablation depth was quantified histologically. RESULTS: In Phase I, complete removal of esophageal epithelium was achieved at energy density settings of 9.7 to 29.5 J/cm 2 . In Phase II, 9.7 and 10.6 J/cm 2 produced no stricture, whereas more than 20 J/cm 2 produced a stricture in every case. In Phase III, 8-20 J/cm 2 resulted in 100% epithelial ablation. Five and 8 J/cm 2 spared the muscularis mucosae, whereas 10 J/cm 2 caused injury to the muscularis mucosae but preserved the submucosa. In Phase IV, histologic examination demonstrated full-thickness epithelial removal in areas of electrode contact. Ablation extended only to the muscularis mucosae, without injury to submucosa. CONCLUSIONS: In the porcine and the human esophagus, circumferential, full-thickness ablation of epithelium without direct injury to the submucosa is possible and was well tolerated. In all cases, depth of ablation was linearly related to energy density of treatment.

Adenocarcinoma↗

PubMed2003

The Stretta procedure: device, technique, and pre-clinical study data.

The initial concept of delivering RF energy to the gastroesophageal junction for the treatment of GERD was based on the well-established safety profile and scientific clinical evidence supporting the effectiveness of this technology in other disease states. As described in this article, the Stretta procedure is an endoluminal procedure inducing collagen tissue contraction, remodeling, and modulation of the triggering threshold for transient LES relaxations. The preclinical experience with this device included feasibility studies to determine optimal treatment parameters and device design. This was followed by longitudinal animal studies to elucidate the mechanism of safety and effect of this intervention as it relates to LES physiology and histopathology. In these studies, RF elevated the LES pressure and gastric yield pressure in a porcine model of botulinum toxin induced LES hypotension. The elevation in GYP more than 6 months was confirmed in a subsequent evaluation. Thickening of the LES after RF delivery has been demonstrated using histopathological evaluation and EUS. Additionally, using a canine model of triggered transient LES relaxations (tLESR), RF significantly reduced the frequency of tLESRs and reflux events. Additional evaluation was performed in human subjects undergoing esophagectomy, confirming feasibility and Histopathologic results of the treatment. Subsequent clinical trials confirm the safety and mechanism of action data of these pre-clinical studies and are presented in this publication.

Animals↗

PubMed2003

Radiofrequency energy delivery to the gastric cardia inhibits triggering of transient lower esophageal sphincter relaxation and gastroesophageal reflux in dogs.

BACKGROUND: Delivery of radiofrequency energy to the lower esophageal sphincter and gastric cardia is a new endoluminal technique proposed for the treatment of reflux disease. The mechanisms by which it achieves its effects are unclear. The study assessed the effect of radiofrequency energy delivery to the gastric cardia on the triggering of transient lower esophageal sphincter relaxations and gastroesophageal reflux in dogs. METHODS: In 13 dogs, esophageal motility and pH were measured for 1 hour after a standard liquid meal and air infusion, as well as before and 3 months after radiofrequency energy treatment. At 7 months, histologic evaluation of the gastroesophageal junction was performed. RESULTS: Radiofrequency energy delivery reduced the frequency of transient lower esophageal sphincter relaxations from 4.0 (3.0-6.75) (median [interquartile range]) per hour to 3.0 (2.0-3.0) per hour (p < 0.05). This was accompanied by a significant reduction in acid reflux episodes and esophageal acid exposure. Basal lower esophageal sphincter pressure and lower esophageal sphincter relaxation during swallowing were unchanged. There was a 63% increase in wall thickness at the gastric cardia compared with that in 2 control dogs, but no gross or histopathologic abnormalities of the esophageal or gastric mucosa. CONCLUSION: Radiofrequency energy delivery to the gastric cardia in dogs inhibits the triggering of transient lower esophageal sphincter relaxations and thereby reduces gastroesophageal reflux.

Animals↗

PubMed2002

Radio-frequency energy delivery to the anal canal for the treatment of fecal incontinence.

PURPOSE: In this prospective study we investigated the feasibility, safety, and efficacy of radio-frequency energy delivery deep to the mucosa of the anal canal for the treatment of fecal incontinence. METHODS: We studied ten patients with fecal incontinence of varying causes. All patients underwent anoscopy, anorectal manometry, endorectal ultrasound, and pudendal nerve terminal motor latency testing at baseline and six months. The Cleveland Clinic Florida scale for fecal incontinence (Wexner, 0-20), fecal incontinence-related quality of life score, and Short Form 36 were administered at baseline, 1, 2, 3, 6, and 12 months. Using conscious sedation and local anesthesia, we delivered temperature-controlled radio-frequency energy via an anoscopic device with multiple needle electrodes to create thermal lesions deep to the mucosa of the anal canal. RESULTS: Ten females (age, 55.9 +/- 9.2 years; range, 44-74) were enrolled and treated. Median discomfort by visual analog scale (0-10) was 3.8 during and 0.9 two hours after the procedure. Bleeding occurred in four patients (14-21 days after procedure), spontaneous resolution (n = 3) and anoscopic suture ligation (n = 1). At 12 months, the median Wexner score improved from 13.5 to 5 (P < 0.001), with 80 percent of patients considered responders. All parameters in the fecal incontinence-related quality of life were improved (lifestyle (from 2.3 to 3.4), coping (from 1.4 to 2.7), depression (from 2.2 to 3.5), and embarrassment (from 1.3 to 2.8); P < 0.05 for all parameters). Protective pad use was eliminated in five of the seven baseline users. At six months, there was a significant reduction in both initial and maximum tolerable rectal distention volumes. Anoscopy was normal at six months. CONCLUSION: Radio-frequency energy delivery to the anal canal for treatment of fecal incontinence is a new modality that, in this study group, safely improved Wexner and fecal incontinence-related quality of life scores, eliminated protective pad use in most patients, and improved patient quality of life.

Adult↗

PubMed2002

The Stretta procedure for the treatment of GERD: 6 and 12 month follow-up of the U.S. open label trial.

BACKGROUND: This multicenter prospective study investigated the longer-term (12 month) safety and efficacy of radiofrequency energy delivery for the treatment of GERD. METHODS: A prospective study was conducted of 118 patients with chronic heartburn and/or regurgitation who required antisecretory medication daily and had demonstrated pathologic esophageal acid exposure, a sliding hiatal hernia (<or=2 cm), and esophagitis (<or= grade 2). RF energy was delivered with the Stretta catheter and thermocouple-controlled generator to create thermal lesions below the mucosa at the gastroesophageal junction. GERD symptom scores, quality of life (SF-36), and medication use were assessed at 0, 1, 4, 6, and 12 months; esophageal acid exposure, motility, and endoscopy were assessed at 0 and 6 months. RESULTS: Seventy-two men and 46 women were treated. At 12 months, 94 patients were available for follow-up. There were improvements after 12 months in the median heartburn score (4 to 1, p = 0.0001), GERD score (27 to 9, p = 0.0001), satisfaction (1 to 4, p = 0.0001), mental SF-36 (46.3 to 55.4, p < 0.0001), and physical SF-36 (40.9 to 53.1, p = 0.0001); proton pump inhibitor requirement fell from 88.1% to 30% of patients. Esophageal acid exposure improved significantly (10.2% to 6.4%, p = 0.0001). There were 10 (8.6%) complications, none of which required therapeutic intervention. CONCLUSION: The Stretta procedure significantly improves GERD symptoms, quality of life, and esophageal acid exposure and eliminates the need for antisecretory medication in the majority of patients at 12 months.

Adult↗