Recent advances in the use of stents for esophageal disease

A phase III, multicenter, prospective, single-blinded, noninferiority, randomized controlled trial on the performance of a novel esophageal stent with an antireflux valve (with video)

BACKGROUND AND AIMS

Self-expanding metal stents (SEMSs) when deployed across the gastroesophageal junction (GEJ) can lead to reflux with risks of aspiration. A SEMS with a tricuspid antireflux valve (SEMS-V) was designed to address this issue. The aim of this study was to evaluate the efficacy and safety of this stent.

METHODS

A phase III, multicenter, prospective, noninferiority, randomized controlled trial was conducted on patients with malignant dysphagia requiring SEMSs to be placed across the GEJ. Patients were randomized to receive SEMSs with no valve (SEMS-NV) or SEMS-V. Postdeployment dysphagia score at 2 weeks and Gastroesophageal Reflux Disease-Health Related Quality of Life (GERD-HRQL) questionnaire score at 4 weeks were measured. Patients were followed for 24 weeks.

RESULTS

Sixty patients were randomized (SEMS-NV: 30 patients, mean age 67 ± 13 years; SEMS-V: 30 patients, mean age 65 ± 12 years). Baseline dysphagia scores (SEMS-NV, 2.5 ± .8; SEMS-V, 2.5 ± .8) and GERD-HRQL scores (SEMS-NV, 11.1 ± 8.2; SEMS-V, 12.8 ± 8.3) were similar. All SEMSs were successfully deployed. A similar proportion of patients in both arms improved from advanced dysphagia to moderate to no dysphagia (SEMS-NV, 71%; SEMS-V, 74%; 95% confidence interval, 1.93 [-17.8 to 21.7]). The dysphagia scores were also similar across all follow-up time points. Mean GERD-HRQL scores improved by 7.4 ± 10.2 points in the SEMS-V arm and by 5.2 ± 8.3 in the SEMS-NV group (P = .96). The GERD-HRQL scores were similar across all follow-up time points. Aspiration pneumonia occurred in 3.3% in the SEMS-NV arm and 6.9% in the SEMS-V arm (P = .61). Migration rates were similar (SEMS-NV, 33%; SEMS-V, 48%; P = .29). Two SEMS-V spontaneously fractured. There was no perforation, food impaction, or stent-related death in either group.

CONCLUSIONS

The SEMS-V was equally effective in relieving dysphagia as compared with the SEMS-NV. Presence of the valve did not increase the risks of adverse events. GERD symptom scores were similar between the 2 stents, implying either that the valve was not effective or that all patients on proton pump inhibitors could have masked the symptoms of GERD. Studies with objective evaluations such as fluoroscopy and/or pH/impedance are recommended. (Clinical trial registration number: NCT02159898.).

In Vitro Evaluation of Mechanical Properties of Segmented Esophageal Self-Expandable Metal Stents: Innovative Test Methods Are Needed

Background: Self-expanding metal stents (SEMSs) in different geometric shapes are well established treatment options in diseases of the esophagus. Mechanical properties and stent design may have an impact on patient comfort, migration rate, and removability. In this in vitro study, we evaluated mechanical properties of three segmented SEMSs (segSEMSs) for the esophagus with regard to distinct stent sections. Materials and Methods: Radial forces were measured using a testing method distinguishing between circumferential radial and local radial force. The center parts of the segSEMSs were measured for circumferential radial forces without being affected by the flared ends. Axial forces were measured at 20° bending. Results: Circumferential radial force measurements over the full stent length showed substantial differences against measurements of the center parts of the stents as the flared ends falsify test results by up to 53%. Although circumferential radial forces of the center parts were about the same (<10% variances) for all segSEMSs, local radial forces showed considerable differences of up to 26%. One segSEMS showed high axial forces, whereas the other two only needed half of the force (up to 53%) to be bent to 20°. Conclusion: Flared ends of segSEMSs have a substantial impact on radial force measurements and therefore alter test results, confirmed by our separated center part test of segSEMSs. Our innovative setup whereby we compressed the stent in an asymmetric manner (local radial force) and evaluated sections of stents separately, indeed revealed differences to circumferential measurements, leading to a more in-depth knowledge of stent characteristics.

Role of stenting in gastrointestinal benign and malignant diseases

Advances in stents design have led to a substantial increase in the use of stents for a variety of digestive diseases. Initially developed as a non-surgical treatment for palliation of esophageal cancer, the stents now have an emerging role in the management of malignant and benign conditions as well as in all segments of the gastrointestinal tract. In this review, relevant literature search and expert opinions have been used to evaluate the key-role of stenting in gastrointestinal benign and malignant diseases.

The role of clips in preventing migration of fully covered metallic esophageal stents: a pilot comparative study

BACKGROUND

Migration is the most common complication of the fully covered metallic self-expanding esophageal stent (SEMS). This study aimed to determine the potential preventive effect of proximal fixation on the mucosa by clips for patients treated with fully covered SEMS.

METHODS

In this study, 44 patients (25 males, 57%) were treated with fully covered SEMS including 22 patients with esophageal stricture (4 malignant obstructions, 6 anastomotic strictures, and 12 peptic strictures) and 22 patients with fistulas or perforations (10 anastomotic leaks, 4 perforations, and 8 postbariatric surgery fistulas). The Hanarostent (n = 25), Bonastent (n = 5), Niti-S (n = 12), and HV-stent (n = 2) with diameters of 18 to 22 mm and lengths of 80 to 170 mm were used. Two to four clips (mean, 2.35 ± 0.75 clips) were used consecutively in 23 patients to fix the upper flared end of the stent with the esophageal mucosal layer. Stent migration and its consequences were collected in the follow-up assessment with statistical analysis to compare the patients with and without clip placement.

RESULTS

No complication with clip placement was observed, and the retrieval of the stent was not unsettled by the persistence of at least one clip (12 cases). Stent migration was noted in 15 patients (34%) but in only in 3 of the 23 patients with clips (13%). The number of patients treated to prevent one stent migration was 2.23. The predictive positive value of nonmigration after placement of the clip was 87%. In the multivariate analysis, the fixation with clips was the unique independent factor for the prevention of stent migration (odds ratio, 2.3; 95% confidence interval, 0.10-0.01; p = 0.03).

CONCLUSIONS

Anchoring of the upper flare of the fully covered SEMS with the endoscopic clip is feasible and significantly reduces stent migration.

Diagnosis and initial management of gastroesophageal complications

Chronic esophageal exposure to reflux of gastroduodenal contents can result in complications of GERD including esophageal stricture, Barrett's oesophagus or extraesophageal symptoms such as laryngitis, chronic cough or asthma. Endoscopy is the main diagnostic tool for patients with chronic reflux presenting with dysphagia to visualise esophageal mucosa and identify the underlying pathology. Barrett's oesophagus should be suspected in those with chronic reflux disease. Patients with Barrett's oesophagus should undergo surveillance endoscopy in order to risk stratify to dysplasia or adenocarcinoma. New endoscopic ablative therapies in patients with Barrett's oesophagus and high grade dysplasia are promising new treatment modality for those who may not be candidates for definitive intervention. Given poor sensitivity of diagnostic tests in extraesophageal reflux, empiric therapy with proton pump patients is the initial recommended approach. Diagnostic testing with esophagogastroduodenoscopy and ambulatory pH and impedance monitoring is usually reserved for those unresponsive to acid suppressive therapy. Many uncertainties remain in this group of patients including which patient subgroups might benefit from acid suppressive therapy. Future outcome studies are needed to assess the role of impedance/pH monitoring in this group of patients and to determine who might symptomatically benefit from medical or surgical intervention.

Covered versus uncovered self-expandable nitinol stents in the palliative treatment of malignant distal biliary obstruction: results from a randomized, multicenter study

BACKGROUND

Covered biliary metal stents have been developed to prevent tumor ingrowth. Previous comparative studies are limited and often include few patients.

OBJECTIVE

To compare differences in stent patency, patient survival, and complication rates between covered and uncovered nitinol stents in patients with malignant biliary obstruction.

DESIGN

Randomized, multicenter trial conducted between January 2006 and October 2008.

SETTING

Ten sites serving a total catchment area of approximately 2.8 million inhabitants.

PATIENTS

A total of 400 patients with unresectable distal malignant biliary obstruction.

INTERVENTIONS

ERCP with insertion of covered or uncovered metal stent. Follow-up conducted monthly for symptoms indicating stent obstruction.

MAIN OUTCOME MEASUREMENTS

Time to stent failure, survival time, and complication rate.

RESULTS

The patient survival times were 116 days (interquartile range 242 days) and 174 days (interquartile range 284 days) in the covered and uncovered stent groups, respectively (P = .320). The first quartile stent patency time was 154 days in the covered stent group and 199 days in the uncovered stent group (P = .326). There was no difference in the incidence of pancreatitis or cholecystitis between the 2 groups. Stent migration occurred in 6 patients (3%) in the covered group and in no patients in the uncovered group (P = .030).

LIMITATIONS

Randomization was not blinded.

CONCLUSIONS

There were no significant differences in stent patency time, patient survival time, or complication rates between covered and uncovered nitinol metal stents in the palliative treatment of malignant distal biliary obstruction. However, covered stents migrated significantly more often compared with uncovered stents, and tumor ingrowth was more frequent in uncovered stents.