Survival and complications after insertion of self-expandable metal stents for malignant oesophageal stenosis

Endoscopic Management of Luminal Strictures: Beyond Dilation

Luminal strictures can occur as part of many different gastrointestinal (GI) disorders anywhere along the GI tract and affect all age groups. The end goal of managing any stricture is to re-establish an adequate and durable luminal patency that is sufficient to resolve the presenting clinical symptoms. Treatment options can be generally categorized into medical, endoscopic, and surgical. However, within each of these categories, multiple different options are available. Therefore, choosing the best treatment modality is often challenging and depends on multiple factors including the type, location, and complexity of the stricture, as well as the preference of the treating physician. In this article, we will review the most current literature regarding foregut strictures, particularly esophageal and gastric, beyond dilation.

A rare case of a chest wall abscess caused by a migrating oesophageal stent. An iatrogenic gastrocutaneous fistula

We report the case of a 65-year-old male, who presented with septicaemia and a chest wall mass on a background of oesophageal carcinoma. This chest wall mass measured 10 cm by 10 cm, was fluctuant, and was situated on the anterior chest wall. Owing to local erythema and surgical emphysema, necrotising fasciitis was suspected and thus intravenous antibiotic and fluid therapy were instituted. Following a chest radiograph, which confirmed the presence of subcutaneous gas, the patient underwent thoraco-abdomino-pelvic CT, which demonstrated oesophageal stent migration through the gastric fundus to the chest wall, between the 10th and 11th left ribs. Through this migration tract, the chest wall was contaminated with gastric contents, accounting for the mass and sepsis. The patient underwent endoscopic stent removal, and incision and drainage to create a gastrocutaneous fistula. Additionally, a nasojejunal tube and intravenous line were sited for jejunal and total parenteral nutrition, respectively, in order to promote healing of the fistula.

Endoscopy in Patients on Antiplatelet Agents and Anticoagulants

OPINION STATEMENT

Management of patients on anticoagulant or antiplatelet therapy undergoing endoscopy presents a balance of risks between haemorrhage due to the procedure, and thrombosis due to discontinuation of antithrombotic therapy. Haemorrhage is usually controllable endoscopically, but thrombosis could, on occasion, result in myocardial infarction or stroke, with permanent disability or death. For elective procedures, there is adequate time to plan best management of antithrombotic therapy. International guidelines have been published, but recommendations are based on limited evidence and consultation with appropriate medical specialists, and the patient is important. Patients on dual antiplatelet therapy for coronary stents are at particularly high risk of thrombosis if therapy is interrupted. Direct oral anticoagulants have been a great advance in the management of anticoagulation but can present an increased risk of spontaneous gastrointestinal haemorrhage, as well as a difficult management situation in haemorrhage following endoscopic therapy. For elective endoscopic procedures, there may be a suitable alternative investigation, and some patients can have therapy deferred if high-risk antithrombotic therapy is temporary. Gastrointestinal haemorrhage on antithrombotic therapy can present a life-threatening situation from potential thrombosis as well as haemorrhage. Management is particularly challenging on direct oral anticoagulants (DOACs), but a reversal agent is available for dabigatran, and others are in development. The safest time to restart antithrombotic therapy after therapeutic procedures or haemorrhage has been little studied, and the relevant risk factors are discussed together with advice on management. Although guidelines have been produced, there remains much uncertainty in the management of antithrombotic therapy for endoscopy, particularly for newer agents, and further research is required.

Complications of therapeutic gastroscopy/colonoscopy other than resection

Gastrointestinal (GI) endoscopy is profoundly utilized for diagnostic and therapeutic purposes. The therapeutic potential of GI endoscopy has amplified many folds with the evolution of novel techniques as well as equipments. However, with the augmentation of therapeutic endoscopy, the extent, likelihood and severity of adverse events have increased as well. The attendant risks and adverse events with therapeutic endoscopy are many folds that of diagnostic endoscopy. Besides endoscopic resection, therapeutic endoscopy is widely utilized for hemostasis in GI bleeds, dilatation of stenosis, enteral stenting, foreign body removal, ablation of Barrett's esophagus etc. Major adverse events associated with interventional endoscopic procedures include bleeding and perforation. Adverse events of endoscopic interventions are diverse and related to the underlying disease, therapeutic modality used and operator's experience. Many of these adverse events can be prevented. Early recognition of an unavoidable adverse event is important to minimize the associated morbidity and mortality.

Effect of a paclitaxel-eluting metallic stent on rabbit esophagus

The use of self-expanding metallic stents (SEMS) is the current treatment of choice for malignant gastrointestinal obstructions. A paclitaxel-eluting metallic SEMS (PEMS) may have an antitumor effect on esophageal tissue. PEMS with 10% paclitaxel or conventional SEMS were inserted into the lower esophagus of rabbits. Following the insertion of the stents for 1, 2, 4 and 6 weeks, the rabbits were sacrificed and the status of the stent insertion was examined, as well as any macroscopic or microscopic mucosal changes in the esophageal tissue. All the rabbits survived until death without any complications. No migration following stent insertion occurred. The number of cases with proximal obstruction increased in a time-dependent manner, and no significant difference was observed between the two groups. Gross histological examination showed similar tissue reaction to the stents at 1, 2 and 4 weeks, and inflammatory cell infiltrating was higher in the SEMS group at 1 and 2 weeks. However, inflammatory cell infiltration was markedly higher in the PEMS group at 4 and 6 weeks. Food-intake and weight were similar in the two groups. The results of the present study demonstrated that PEMS may serve as a safe alternative treatment strategy for esophageal obstruction. Furthermore, PEMS may inhibit the tumor growth of the esophageal wall through inflammatory infiltration and targeted drug delivery. A tumor model will be required in the future for evaluating the prognosis of patients with advanced esophageal carcinoma.

Endoscopy in patients on antiplatelet or anticoagulant therapy, including direct oral anticoagulants: British Society of Gastroenterology (BSG) and European Society of Gastrointestinal Endoscopy (ESGE) guidelines

The risk of endoscopy in patients on antithrombotics depends on the risks of procedural haemorrhage versus thrombosis due to discontinuation of therapy. P2Y12 RECEPTOR ANTAGONISTS CLOPIDOGREL, PRASUGREL, TICAGRELOR: For low-risk endoscopic procedures we recommend continuing P2Y12 receptor antagonists as single or dual antiplatelet therapy (low quality evidence, strong recommendation); For high-risk endoscopic procedures in patients at low thrombotic risk, we recommend discontinuing P2Y12 receptor antagonists five days before the procedure (moderate quality evidence, strong recommendation). In patients on dual antiplatelet therapy, we suggest continuing aspirin (low quality evidence, weak recommendation). For high-risk endoscopic procedures in patients at high thrombotic risk, we recommend continuing aspirin and liaising with a cardiologist about the risk/benefit of discontinuation of P2Y12 receptor antagonists (high quality evidence, strong recommendation).

WARFARIN

The advice for warfarin is fundamentally unchanged from British Society of Gastroenterology (BSG) 2008 guidance.

DIRECT ORAL ANTICOAGULANTS DOAC

For low-risk endoscopic procedures we suggest omitting the morning dose of DOAC on the day of the procedure (very low quality evidence, weak recommendation); For high-risk endoscopic procedures, we recommend that the last dose of DOAC be taken ≥48 h before the procedure (very low quality evidence, strong recommendation). For patients on dabigatran with CrCl (or estimated glomerular filtration rate, eGFR) of 30-50 mL/min we recommend that the last dose of DOAC be taken 72 h before the procedure (very low quality evidence, strong recommendation). In any patient with rapidly deteriorating renal function a haematologist should be consulted (low quality evidence, strong recommendation).

Feasibility, efficacy and safety of stent insertion as a palliative treatment for malignant strictures in the cervical segment of the esophagus and the hypopharynx

BACKGROUND

50% of esophageal cancers are inoperable at the time of diagnosis, and around 15% involve the cervical esophagus. The hypopharynx is often involved by these malignancies as well. Palliation of cervical esophageal malignancies through stent insertion is considered limited due to technical challenges, poor patient tolerance and high complication rate. The aim of this study is to review our experience with stent insertion in the cervical segment of the esophagus and to evaluate outcome differences between stent insertions involving or sparing the hypopharynx.

METHODS

We retrospectively reviewed data on 69 consecutive patients that underwent stent insertion for malignant strictures in the cervical esophagus at our Department. Patients were divided according to involvement or sparing of the lower hypopharynx. Dysphagia severity was measured with the Mellow-Pinkas scale before the procedure and on monthly follow-ups. Any complication and its management were recorded. The main outcome parameters were as follows: dysphagia improvement, rate of successful dysphagia palliation (i.e., a reduction of the score to 0 or 1 after stent insertion) and complication rate. Multivariable analysis was carried out to assess the influence of patient- and procedure-related factors on the outcome of the procedure.

RESULTS

Stent insertion was achieved in 100% patients. At 4 weeks, dysphagia score improved from a median of 3-0 (p < 0.001), and a successful palliation was achieved in 76.8% patients. The 30-day mortality rate was 14.5%. Successful palliation throughout the follow-up was achieved in 72.9% of the surviving patients. Complications occurred in 31.9% patients. Dilation before stent insertion was associated with a less efficient short-term dysphagia palliation (OR 6.77, 95% CI 1.46-31.29, p = 0.02).

CONCLUSIONS

Stent insertion is a safe and effective palliative treatment for malignant cervical esophageal strictures. Results are consistent even in patients with hypopharyngeal lesions. Dilation should be avoided before stent insertion.

Tracheo-oesophageal fistula after palliative treatment of oesophageal cancer

We present a case of an 86-year-old male who presented with severe pneumonia in the context of having undergone radiotherapy and then an oesophageal stent insertion for palliation of oesophageal cancer. He was diagnosed with a tracheo-oesophageal fistula (TOF) which was successfully managed by deploying a second stent within the first stent.

Ten-year experience of esophageal self-expanding metal stent insertion at a single institution

Palliation of malignant dysphagia can be achieved using self-expanding metal stents (SEMS). This study was conceived to confirm that the insertion of SEMS improved patient symptoms without serious complications and to allow comparison with recent national data. Retrospective case note review of all patients receiving SEMS over a 10-year period between March 1999 and February 2009 was used in this study. There were 138 consecutive patients (50 female), median age of 75 (range 46-90) years, 122 (88.5%) had primary malignant disease of the esophagus or gastroesophageal junction. In total, 250 endoscopic examinations were carried out, with 200 interventional procedures, including the insertion of 156 SEMS. Before stenting, 74.2% of patients had a dysphagia score of 2-3. Following stent insertion, dysphagia scores improved to 0-1 in 90.3% of patients (P < 0.0001, Wilcoxon signed ranks). No complications were encountered in 61 (44%) patients. Chest pain was the most frequent difficulty, encountered in 50 (36%) patients. Tumor overgrowth occurred in 17 (12.3%) patients and food bolus obstruction was seen in 7% of patients. There were no esophageal perforations attributable to SEMS insertion. Overall 30-day mortality for those with esophago-gastric malignancy was 11.6% (16 patients), although the SEMS-related mortality was 2.2% (3 patients). Median survival from SEMS insertion was 3 (IQR 1.5-7) months. Patients requiring re-intervention for tumor overgrowth had a significantly longer median survival of 9.2 months (P= 0.001, log rank). SEMS were well tolerated with overall mortality and complication rates comparable to national data. For the longer survivors, re-intervention for recurrent dysphagia was not unusual.

Self-expanding metal stents (SEMS) for patients with advanced esophageal cancer in Malawi: an effective palliative treatment

BACKGROUND AND OBJECTIVES

Esophageal cancer is common in Malawi and most patients are inoperable at time of diagnosis. The aim of this study was to prospectively evaluate palliative treatment with self-expanding metal stents (SEMS) in Malawi, a low-income country with limited medical resources.

METHODS

Data of patients with advanced inoperable esophageal cancer were prospectively collected. Tumor and patient specifics, risk factors, dysphagia scores, complications, and survival were assessed. Follow-up data for 1 year or until death were collected from 118/143 patients (83%) during clinic visits, home visits, or via cell phone.

RESULTS

One hundred forty-three patients were treated with 154 SEMS. Median survival was 210 days (95% CI: 150-262 days). Fourteen of 118 patients with complete follow-up (11.9%) survived more than 1 year with longest documented survival of 406 days. The median dysphagia score improved from 3 at the time of presentation to 0 at the time of death. Early complications occurred in 4.2% (6/143), late complications in 11.9% of patients (14/118). The procedure related mortality was 2.1% (3/143).

CONCLUSIONS

SEMS is an appropriate palliative treatment in a resource-limited environment. For the vast majority of patients a single intervention provides lasting improvement of dysphagia.

A comparative study between fluoroscopic and endoscopic guidance in palliative esophageal stent placement

Self-expanding metallic stents (SEMS) are the treatment of choice for incurable obstructive malignant esophageal strictures. Although the placement of SEMS is usually performed with fluoroscopic control (FC), recently several authors have shown the feasibility of placing SEMS under endoscopic control alone (EC). However, studies comparing the two techniques are lacking. The objective of this study was to compare the feasibility and safety of SEMS insertion under fluoroscopic control and endoscopic control. The study was performed through the retrospective analysis of patients who underwent SEMS insertion for malignant dysphagia between January 2005 and January 2010. Data concerning early and late complications and survival were retrieved. Early complications were defined as pain, vomiting, bleeding, malposition/migration, perforation, and/or dysphagia occurring until 30 days of SEMS insertion; and late complications as tumor ingrowth and overgrowth, migration, hemorrhage, fistulae, food impaction, and/or esophagitis occurring after 30 days. We placed 126 SEMS of which 87% for esophageal stricture, 8% for esophagus-respiratory fistula, and 5% for extrinsic compression. The mean age of the patients was 62 years, and 93 were male. SEMS insertion was performed with FC in 66 patients and EC in 60. Early complications occurred in 34 patients (52%) in the FC group and 28 (47%) in the EC group (P=0.71), including: pain in 22 patients of the FC group and 15 of the EC group (P=0.31); vomiting in 15 of the FC group and nine of the EC group (P=0.27); malposition/migration in three of the FC group and four of the EC group (P=0.60); hemorrhage in one of the FC group and two of the EC group (P=0.27); and dysphagia in two of the FC group and three of the EC group (P=0.57). Late complications occurred in 20 patients (30%) in the FC group and 22 (37%) in the EC group (P=0.44), including: tumor in/overgrowth in 13 patients of the FC group and 10 of the EC group (P=0.66); prostheses migration in five of the FC group and eight of the EC group (P=0.28); hemorrhage in two of the FC group and two of the EC group (P=0.54); appearance of esophageal fistulae in seven of the FC group and four of the EC group (P=0.43); food impaction in nine of the FC group and eight of the EC group (P=0.96); esophagitis in 12 of the FC group and 15 of the EC group (P=0.35). Median survival was 107 days (95% confidence interval [CI]=6-369 days) with no difference between the two groups. There were no statistical significant differences in the incidence of complications and in survival between patients undergoing SEMS placement under fluoroscopic control or endoscopic control.

Esophageal stenting in the setting of malignancy

Esophageal cancer is often diagnosed at an advanced stage, with many patients found to have locoregional or metastatic disease at time of diagnosis. Because of this, cure may be unlikely, leading treatment efforts to focus more on symptom palliation and improving patient quality of life. The majority of patients with advanced disease suffer from some degree of dysphagia. Palliative efforts are therefore directed at relieving dysphagia, allowing patients to manage their oropharyngeal secretions, reduce aspiration risk, and maintain caloric intake orally. A variety of endoscopic treatment modalities have been utilized with these objectives in mind, with options determined by the location and size of the tumor, as well as the patient's expected prognosis. In this article, we review the use of endoscopically-placed stents for palliation in patients with advanced esophageal cancer. We discuss the history of stent use in such cases, as well as more recent developments in stent technology. We give an overview of some of the more commonly used stents in practice, discuss the technique of insertion, and survey the short- and long-term outcomes of stent placement.

[Self-expanding metal stents for palliation of malignant oesophageal obstruction]

BACKGROUND

Malignant oesophageal stenosis can be caused by cancer of the oesophagus, gastric cardia, lungs, mediastinum or, rarely, breast. Most of these cases are inoperable due to advanced stage of the disease, comorbidities or age of the patients; and palliative treatment can be applied only. The quality of life is mostly determined by the extent of dysphagia. Several methods are available to palliate dysphagia. Hereby, the authors review their results with palliation of malignant oesophageal obstruction applying self-expanding metal stents.

PATIENTS AND METHODS

68 endoscopic stent implantations were performed in 64 patients (15 female and 49 male) with malignant dysphagia between 2003 and 2008. After radiological investigations, distally deployed covered stents with or without an antireflux valve were placed, depending on the localization of the tumour. In one patient with a stenosis localized in the upper third of the oesophagus a proximally deployed covered stent was used. The aim was to re-establish oral nutrition and cover possible fistulas.

RESULTS

Significant improvement of swallowing was detected in every patient. Average dysphagia score has improved from 3.2 to 1.7. Technical difficulties during stenting occurred in a relatively low percentage of patients only (2 in 68; i.e. 2.94%). Fistulas were covered in every case. Early stent migration (<7 days) happened in one case. One patient suffered non-fatal myocardial infarction two days after stent placement. In 5 cases tumour in- and overgrowth, in 4 cases bleeding was seen as late complications. Oesophago-tracheal fistula was noted in three patients after stent implantation. Late stent migration (>7 days) occurred in two patients. Re-stenting was necessary in four cases, while three patients needed an upper GI endoscopy for cleansing the stent caused by food obstruction.

CONCLUSIONS

According to our data self-expanding metal stents are highly effective and safe for improving dysphagia. Stent-related complications are relatively rare. This method is highly recommended for palliation of malignant dysphagia.

Modified technique to extract malpositioned or migrated self-expanding stents from the esophagus and stomach

BACKGROUND AND AIM

Various methods have been used to remove self expandable stents (SES) because of either malposition or migration. The main difficulties encountered in such situations are the anatomic obstacle of the lower and upper esophageal sphincters as well as risk of mucosal injury during removal.

METHODS

We describe a modified approach using an esophagogastroduodenoscope (EGD) in combination with a foreign body hood protector, rat tooth forceps and snare allowing for successful SES removal from the upper gastrointestinal tract in four cases.

RESULTS

In all cases, the SES were successfully removed from upper gastrointestinal tract using this technique. No complications were noted after extraction.

CONCLUSION

The foreign body hood protector combined with rat tooth forceps/snare technique is a safe and effective alternative to previously described methods for extraction of SES from the upper gastrointestinal tract. This method may be applicable for the removal of other such objects within the endoscope's reach.

Stents as sole therapy for oesophageal cancer: a prospective analysis of outcomes after placement

BACKGROUND

Therapies for inoperable oesophageal cancer include chemoradiotherapy and placement of a self-expanding metal stent (SEMS). Few data are available regarding SEMS as sole therapy for patients with inoperable disease who have not already received, or are unfit for, chemoradiotherapy. The aim of this study was to determine survival, adequacy of palliation, and complications after SEMS placement as sole therapy for inoperable oesophageal cancer in a resource-limited setting.

METHODS

Data were prospectively gathered on all patients with oesophageal cancer treated with SEMS between Jan 1, 1999, and May 20, 2008, at a hospital in Kenya where chemoradiotherapy is unavailable. Dysphagia scores, morbidity, mortality, and survival were assessed. Follow-up was done during clinic visits, home visits, and by mobile phone.

FINDINGS

1000 stents were placed in 951 patients. Long-term follow-up was obtained for 334 patients (35%) with a median survival of 250 days (IQR 130-431, 95%CI 217-301). Mean dysphagia scores improved from 3.3 (SD 0.6) pre-SEMS (n=697) to 1.0 (SD 1.3) for patients (n=78) still alive and 1.8 (SD 1.2) at time of death (n=165). Survival of 17 patients with follow-up who had perforation during tumour dilation (treated with SEMS) was 283 days (IQR 227-538) similar to the 317 patients with follow-up data who did not have a perforation (245 days, 124-430). 20 patients with a tracheo-oesophageal fistula lived a median of 142 days (IQR 73-329). Early complications occurred in 6% (54 of 951 patients) and late complications occurred in 19% (62 of 334 patients). SEMS-related mortality was 0.3% (three of 951).

INTERPRETATION

SEMS effectively palliate inoperable oesophageal cancer. Survival may be longer than previously reported when SEMS are placed in all patients with inoperable oesophageal cancer, as in our study, rather than those failing or unfit for chemoradiotherapy. SEMS seem to be an appropriate technology for palliation of oesophageal cancer in resource-limited settings. Given the proportion of patients lost to follow up, these findings merit further confirmation.

Advances in research of esophageal stents

Esophageal stents were used initially in the palliative treatment of esophageal carcinoma to improve the life quality of the patients in the advanced stage. Along with the appearance of many new kinds of esophageal stents, esophageal stents have been used in the management of the benign esophageal strictures, and clinical effectiveness has been made. This article reviews the application of the esophageal stents in the benign and malignant esophageal strictures.

Covered expandable nitinol stents for malignant gastroduodenal obstructions

BACKGROUND AND AIM

The aim of the present study was to investigate the clinical effectiveness, safety, and outcome associated with the use of covered expandable Nitinol stents (Taewoong Medical, Seoul, Korea) for the treatment of malignant gastroduodenal obstructions.

METHODS

Between March 2001 and October 2004, covered expandable Nitinol stents were placed in 68 consecutive patients under endoscopic and fluoroscopic guidance for the following reasons: gastric carcinoma (n = 49), recurrent carcinoma after partial gastrectomy (n = 7), or another malignant neoplasm involving the duodenum (n = 12).

RESULTS

Technical success was achieved in 60 of the 68 patients (88.2%). After stent placement, mean dysphagia score improved from a mean of 3.5 to 1.2 (P < 0.001). The mean period of primary stent patency was 107.2 days. During follow up (mean 4.4 months; range, 1-15 months), major complications (migration [6], bleeding [3], perforation [1], ingrowth [1], overgrowth [7], fistula [1]) occurred in 19 patients (27.9%), and stent migration occurred in six (8.8%) (proximal migration into the stomach [n = 3], or distal migration [n = 3]). Recurrent dysphagia (mainly due to tumor ingrowth/overgrowth) occurred in eight patients (11.8%).

CONCLUSION

Covered expandable Nitinol stents appear to offer an effective and feasible palliative therapy in patients with a malignant gastroduodenal obstruction.

Multidetector CT in patients with esophageal stent as a palliative treatment for stenosing esophageal cancer: a feasibility study

OBJECTIVE

The self-expanding metallic stent (SEMS) is widely used in the palliative treatment of stenosing esophageal cancer. Multidetector computed tomography (MDCT) allows volumetric investigation including virtual endoscopy. The aim of this study was to determine the feasibility of MDCT follow-up of esophageal SEMS and to describe the imaging patterns encountered as well as correlating them with fibroscopic evaluation.

MATERIAL AND METHODS

Thirteen consecutive patients (10 M, mean age 64 years) with esophageal SEMS as a palliative treatment underwent MDCT for recurrent dysphagia (n =7), chest pain and fever (n = 1) or follow-up without symptoms (n = 5). Patency and esophageal wall patterns were studied and compared with diagnosis by fibroscopy.

RESULTS

No metallic artefact related to the SEMS was observed. At the SEMS level, MDCT revealed a tissular lump (n = 1), a thin recurrent layer of tissue (n = 1), extrinsic compression (n = 1), fluid stasis (n =7) and intussusception of the gastric wall into the SEMS (n =4). The esophageal wall was analyzed by MDCT (peripheral thickening around the stent (n = 8), tumor overgrowth under or above the SEMS level (n = 8)) and showed tracheal compression (n = 3). At the level of the SEMS, fibroscopy showed tumor recurrence (n = 2), a thin recurrent layer of tissue (n = 1), a distorted SEMS (n = 1) and a tumor overgrowth under or above the SEMS level (n = 6). In comparison with fibroscopy, MDCT satisfactorily diagnosed the SEMS patency in 92% of cases and the esophageal wall in 73%.

CONCLUSIONS

Morphology, patency of the SEMS and analysis of the esophageal wall can be performed by MDCT with a good degree of accuracy as compared to fibroscopy. In such patients in palliative care, a non-invasive investigation is worth promoting as a first-line procedure.

A type of esophageal stent coating composed of one 5-fluorouracil-containing EVA layer and one drug-free protective layer: In vitro release, permeation and mechanical properties

A type of esophageal stent coating was investigated, which consists of one 5-fluorouracil (5-FU)-containing ethylene-vinyl acetate (EVA) copolymer layer and one drug-free EVA protective layer. The amount of 5-FU permeated through the protective layer (100 mum) is thousands of times lower than that of 5-FU released from the drug-loaded layer, indicating that the coating releases drug molecules in a unidirectional fashion. The barrier of the protective layer can be attributed to a tiny flux of 5-FU through the EVA film. In vitro release profiles of the stent coatings with various drug contents were investigated in pH 6.5 phosphate buffer solution. The results show that, the burst effect is not obvious for the coatings with 20-50% of 5-FU and the release profiles can be characterized by a first faster release rate phase followed by a decrease in release rate. The release data in the early and late stages can all be well fitted with zero-order kinetics, and the possible reasons for the release profiles were discussed. The rate of 5-FU permeation through porcine esophageal mucosa from the coatings can be adjusted by changing drug content of the coatings. The increase of drug content of the coatings significantly leads to the decrease of the maximum elongation, maximum tensible strength and maximum tear strength, and the increase of the modulus of elasticity. The coatings with 20-60% of drug attached to a stent can endure repeated binding and liberation via a stent introducer.