Comparison of natural and Dumon airway stents for the management of benign tracheobronchial stenoses

Objective and background:   To investigate the utility and safety of the 'Natural stent', a newly designed silicone airway stent, the authors compared clinical outcomes and complications in patients who underwent silicone airway stenting for the management of benign airway stenosis.
Methods:   The medical records of 94 patients requiring the placement of 100 airway stents (43 Dumon and 57 Natural) were retrospectively reviewed in a tertiary referral hospital.
Results:   Post-tuberculous stenosis was the leading indication for airway stenting (74%), followed by post-intubation stenosis (21%). After intervention, dyspnoea improved in patients who underwent Dumon (90%) and Natural (86%) stenting. After stabilizing dyspnoea, stents could be successfully removed in half of the patients who underwent Dumon (54%) or Natural (49%) stenting. During a 42-month follow-up period, complication rates were similar in patients who underwent Dumon or Natural stenting.
Conclusion:   Natural airway stent was as effective and safe as Dumon stent for the management of benign tracheobronchial stenoses.     

Evaluation of a new self-expandable silicone stent in an experimental tracheal stenosis

STUDY OBJECTIVES: To assess the usefulness of an animal model for testing new tracheobronchial stents. SETTING: Animal laboratory of a university hospital. ANIMALS AND INTERVENTIONS: In a series with 12 mini-pigs, we induced a stable fibromalacic tracheal stenosis that was 50% to 70% of the normal tracheal diameter. After dilation we inserted a 16 x 40-mm self-expandable silicone stent into the stenotic part of the trachea in 10 of the mini-pigs. Five of the stents had a smooth outer surface, and five had additional silicone retaining spikes. Because of a long stenosis in two of the mini-pigs, two overlapping stents (one smooth and one with spikes) were inserted. MEASUREMENTS AND RESULTS: Stent deployment was successful and resulted in the disappearance of the slight to moderate stridor in all of the mini-pigs. Over a mean (+/- SD) observation period of 24 days (range, 10 to 41 days), all of the mini-pigs redeveloped stridor. Three of them died unexpectedly of suffocation: in all three a smooth stent had migrated, leading to total obstruction of the stenosis. In total, five of the six smooth stents migrated, and only one of the six spiked stents migrated. There was considerable granulation tissue formation at the ends of all of the stents. In the two control mini-pigs, a 12 x 35-mm Dumon stent was inserted. Both Dumon stents migrated, and one of them had considerable granuloma formation at its ends. At the end of the observation period, all stents were removed endoscopically and were found not to have deteriorated over time. CONCLUSIONS: Our model proved to be suitable for the evaluation of the technical aspects of the Polyflex stent. Spikes on the outer stent surface are more effective in preventing migration than smooth-surface stents. Long-term compatibility, however, seems to be difficult to test with our model because both the Polyflex and the Dumon stents had excessive granulation tissue formation at both ends, a factor which--in the case of the Dumon stent--does not occur to such a degree in benign human airway stenoses. Our results indicate a need for prospective long-term studies in benign human airway stenoses.     

Successful treatment of benign tracheal stenosis with a silicone stent (Polyflex-Stent) over 5 years

Inoperable, functional relevant stenoses of the airways can be effectively treated short-termed and medium-termed by means of bronchoscopic stenting occasionally, silicone stents cause problems after long-term periods, such as migration and retention of bronchial secretions. Metallic stents can lead to obstructing granulomas or even bronchial wall perforation. As regards long-term treatment with airway stents over several years, there is little experience and no uniform recommendations are known. We report on a 76-year old female patient with a severe benign subglottic tracheostenosis after tracheostomy who was successfully treated by means of bronchoscopic dilatation and stenting with a silicone stent (POLYFLEX stent). POLYFLEX Stent is a self-expanding silicone stent with an encapsulated monofilament network made of polyester. The network is completely covered by a silicone layer with a smooth inner surface (protecting against incrustation) and a structured outer surface of the stent (protecting against migration). The ends of the monofilaments were provided with a special protection to avoid tissue granulation and to yield x-ray contrast. During a follow-up of almost 5 years the stent is well tolerated and there is no restenosis. Complications such as migration, obstructing secretions and obstructing granulomas did not occur. A slight bronchial hypersecretion presented no problem under regular inhalation therapy with isotonic NaCl solution. 21 and 56 months after stenting there were two episodes of minor haemoptysis. There was no demonstrable source of haemorrhage by bronchoscopy. After 56 months, biopsy at the distal opening of the stent showed a squamous cell metaplasia, but no granulation tissue. Microbiological analysis of bronchial secretions revealed an increasing, but clinically silent colonisation with potentially pathogenic microorganisms.     

INSERTION OF METALLIC STENTS FOR MALIGNANT GASTRIC OUTLET AND DUODENAL STENOSES

Recently, an indication of gastrointestinal stenting is not only esophageal stenosis but it extends from the esophagus to the gastric outlet and duodenum. However, there are some problems such as shortness of the device for esophageal stenting, angulations of stenotic sites, and so on, when we perform the stenting for stenoses of the gastric outlet and duodenum. Until now, some refinements of stent insertion technique have been attempted to solve these problems. In this paper, we report three cases in which self‐expanding metallic stents were placed for stenoses of the gastric outlet and duodenum with refinements of stent insertion technique. Our attempts in these patients were an extension of stenting device to insert stents easily, and placement of covered metallic stent inside non‐covered metallic stent or a fixation of covered metallic stent to the gastrointestinal wall by means of endoclips to avoid dislocation of stents. Stents were inserted successfully in all patients, and the nutrition of these patients was improved after the placement of stents. Further refinements of stents and stent insertion technique are expected to achieve easy manipulation.     

Clinical and angiographic outcomes are similar with half, single, or multiple contiguous Palmaz-Schatz stent implantations for a single coronary stenosis

We compared the immediate and 6-month clinical and angiographic outcomes in patients undergoing a half, a single, or multiple contiguous stent implantations for a single coronary stenosis. Four hundred forty-three consecutive patients, who underwent elective Palmaz-Schatz stent implantations for 542 stenoses between November 1995 and July 1998, were analyzed. Sixty-three patients with 78 stenoses received a half stent (group A), 346 patients with 395 stenoses received a single stent (group B), and 68 patients with 69 stenoses received multiple overlapping stents (group C) for a single coronary stenosis. Seventy-eight half stents were implanted in 78 stenoses in group A, 395 stents in 395 stenoses in group B, and 141 stents in 69 stenoses in group C. The baseline characteristics were similar in the 3 groups. There were no deaths, no subacute thrombosis, and no vascular complications. Forty-nine patients with 57 stenoses in group A, 280 patients with 326 stenoses in group B, and 59 patients with 60 stenosis in group C underwent 6-month follow-up coronary angiography; the restenotic rate per patient was 10% in group A, 20% in group B, and 24% in group C (NS); the restenotic rate per stenosis was 9% in group A, 18% in group B, and 23% in group C (NS). Follow-up of 18 +/- 3 months revealed no differences in mortality, reinfarction, recurrent angina, target narrowing angioplasty, and elective coronary artery bypass surgery among the 3 groups. The overall cardiac event-free survival was 90%, 82%, and 83% in groups A, B, and C, respectively (p = 0.275). Thus, the procedural success rate, the in-hospital morbidity, and the long-term outcome are similar with coronary stenting using a half, a single, or multiple overlapping Palmaz-Schatz stents for a single stenosis.     

Factors predicting outcome following airway stenting for post-tuberculosis tracheobronchial stenosis

Background and objective: Silicone airway stents are used to widen narrowed airways in patients with post‐tuberculosis tracheobronchial stenosis (PTTS). After mechanical stabilization, stents can be removed from the majority of patients leaving restored airway patency. However, in a significant minority re‐stenosis develops post‐sten removal thus necessitating surgical intervention or long‐term stenting. In this study, we sought to establish prognostic factors for successful airway intervention in PTTS. Methods: We retrospectively investigated 71 patients who underwent silicone stenting due to PTTS. After stenting, bronchoscopic toileting and/or repositioning was performed during follow up. At 6–12 months after clinical stabilization, stents were planned to be removed. Patients with patent airways were followed if no further intervention was required. If restenosis developed, patients underwent re‐stenting or operation. Clinical parameters were analysed to determine favourable prognostic factors. Results: Stents were successfully removed in 40 patients at a median 12.5 months after insertion. In 27 patients, stent re‐insertion was carried out and four patients underwent surgical management. Multivariate logistic regression analysis revealed that successful stent removal was independently associated with atelectasis <1 month before bronchoscopic intervention, and absence of complete lobar atelectasis. Conclusions: Airway intervention, including silicone stenting, can be successful in patients with PTTS, when the intervention is performed within 1 month of atelectasis and before complete lobar atelectasis.     

直接支架术治疗左冠状动脉主干病变(附三例报告)

目的评估直接支架术治疗左冠状动脉主干病变的可行性及其术后即刻与远期疗效。方法选择性对３例左主干病变患者进行不预扩左主干的支架直接置入术,其中２例置入ＭｕｌｔｉＬｉｎｋ支架,一例置入ＢｅＳｔｅｎｔ支架。每例均采用高压（１６至２２个大气压）扩张１至２次,持续时间１０至２０秒。结果３例左主干病变直接支架置入术均获成功,术中未发生并发症,术后临床随访６、７及１２个月均无心绞痛症状复发。结论选择性左主干病变直接置入支架术安全、有效、可行。该方法对左主干病变治疗较其他部位及方法可能更为有利,但此需得到大组病例及随机对比试验证实。     

Removal of covered self-expandable metallic airway stents in benign disorders: indications, technique, and outcomes

STUDY OBJECTIVES: To describe the technique and outcome of removal of self-expandable metallic airway stents (SEMAS) in a series of patients who underwent stenting for benign airway stenoses.Design and setting: A retrospective cohort analysis of patients with benign airway disorders treated with SEMAS between 1997 and 2003, who presented with an indication for stent removal in a tertiary-care hospital, and referral interventional pulmonology clinic. PATIENTS AND METHODS: During the study period, 49 SEMAS were inserted in 39 patients for treatment of benign airway disorders. Ten of these 39 patients (25.6%), bearing 12 covered stents, presented with an indication for stent removal. Data of these cases were extracted from electronic files kept in our institution archive. RESULTS: Indications for stent removal included excessive or recurrent granuloma formation (five cases), recurrence of stenosis after stent failure (one case), stent fracture (two cases), and accomplishment of treatment (two cases). In all of these cases, covered versions of SEMAS had been placed either in the trachea or in a main bronchus. In contrast to many previous reports, these stents proved to be absolutely retrievable even if some difficulties were encountered. In all cases, however, removal was successful without major complications. All patients resumed normal spontaneous ventilation postoperatively, and follow-up was uneventful. Average duration of stenting before removal was 16.2 +/- 17.5 months (+/- SD) [range, 1 to 60 months]. CONCLUSIONS: We conclude that although placement of SEMAS is assumed to be permanent in patients with benign airway disorders, an indication for stent removal is often observed (25.6% in our series). The covered SEMAS can be effectively and safely removed if needed without major sequelae. Nevertheless, new technical improvements in metallic stent design and materials may help reinforce the concept of a retrievable metallic airway stent, which may offer significant clinical advantages.     

Vascular stenting in normal and atherosclerotic rabbits. Studies of the intravascular endoprosthesis of titanium-nickel-alloy

Percutaneous transluminal balloon angioplasty would be more effective if the rate of recurrent stenosis were reduced. To evaluate the prevention of restenosis after percutaneous transluminal angioplasty, intravascular endoprosthetic stents of titanium-nickel-alloy were implanted transluminally in seven normal and 21 atherosclerotic rabbits. In normal rabbits, a 3.5-mm diameter stent was implanted in the aorta and a 2.5-mm diameter stent in the right iliac artery, which were followed with serial angiograms from 6 weeks (n = 7) to 8 months (n = 4). There was a mean stenosis of 13.1% in the 2.5-mm and 13.6% in the 3.5-mm stent. There was no significant narrowing compared with the adjacent control segments of artery; histopathology showed a thin, fibrous neointima with smooth muscle cells. Each atherosclerotic rabbit was balloon dilated at two separate stenotic sites; each site was 2.0 cm in length. The aortic site (with 28.8 +/- 13.8% mean stenosis [+/- SD]) was dilated with a 3.5-mm balloon, and the iliac site (with 36.5 +/- 14.2% stenosis) was dilated with a 2.5-mm balloon. In each site, an intravascular stent of corresponding diameter and 7-mm length was implanted in one half of the dilated segment, assigned randomly, and the other half served as the angioplasty control. Angiographically observed restenosis rates and the corresponding histopathology were similar in the atherosclerotic segments that had angioplasty alone versus the atherosclerotic segments that had angioplasty plus stenting. The mean neointimal thickness in the aortas and iliac arteries, respectively, measured 247 +/- 181 microns (+/- SD) and 218 +/- 77 microns after 6 weeks (n = 8) versus 321 +/- 168 and 308 +/- 189 microns after 20 weeks (n = 5, p = NS). At 20 weeks follow-up, there was 29.1 +/- 29.8% (median, 16.4%) stenosis in the aortic stent versus 38.9 +/- 24.1% (median, 34.0%) stenosis in the percutaneous transluminal angioplasty control segment of aorta (n = 5, p = NS) and 81.4 +/- 25.5% stenosis in the iliac artery stent versus 89.3 +/- 15.3% stenosis in the PTA control segment of the right iliac artery (n = 5, p = NS). Comparing stenotic arterial segments treated with angioplasty alone with angioplasty plus intravascular stenting in the atherosclerotic rabbits showed that there was no significant difference in either the histopathologic changes or the restenosis rates.     

Balloon angioplasty and stenting of multiple intralobar pulmonary arterial stenoses in adult patients.

Balloon angioplasty and stent placement for pulmonary arterial stenoses in children are well-established therapies. In contrast, management of isolated peripheral pulmonary arterial stenoses in adults remains relatively unexplored. Four women (ages 18-63 years) with multiple discrete intralobar pulmonary arterial stenoses were treated with balloon angioplasty. Initially, 4-5 stenoses were dilated in each patient. The mean minimum diameter of the stenoses increased from 1.3 to 3.1 mm (P < 0.001), and the mean ratio of right ventricular to aortic systolic pressure decreased from 0.92 to 0.62 (P < 0.05). Each patient had marked symptomatic improvement. However, three patients developed recurrence of symptoms 4-24 months after angioplasty, and two had angiographic evidence of restenosis at previously dilated sites. These restenoses were treated with repeat angioplasty or stent implantation (three stents in each patient). One of these two patients developed near-occlusive restenosis of the stents and had successful bilateral lung transplantation. The other patient had a third catheterization with successful implantation of three additional stents. The third patient with recurrent symptoms died 2 years later, without further intervention. Transcutaneous catheter therapy for multiple intralobar pulmonary arterial stenoses in adults is highly successful acutely, but restenosis is common within several months. For some patients, balloon angioplasty and stent implantation may provide definitive management, while for others these procedures may serve as a bridge to lung transplantation.     

Long-term management of extensive tracheal stenosis due to formic acid chemical burn

We report on a 26-year-old woman who during early infancy (6 months) suffered from a chemical burn of the skin and upper airways due to spill of formic acid powder. Twenty years after the initial injury, she presented with dyspnea and stridor due to severe tracheal stenosis. Several interventional bronchoscopic manipulations were initiated: incision of the stenotic lesion with Nd:YAG laser and dilatation with a valvuloplasty balloon which enabled silicone stent placement which was subsequently kept in place for 3 years. Complications during the 4th year after stenting led to the successful replacement of this stent by two autoexpandable metallic stents covering the total length of the trachea from the subglottic area to the carina. In post-burn inhalation injuries, a complex inflammatory process may be active for many years after the initial insult. These injuries respond to prolonged tracheal stenting and a conservative approach is recommended.     

Airway stenting for the treatment of laryngotracheal stenosis secondary to thyroid cancer

Background and objective:   Airway stenting can be a valuable therapeutic option for symptomatic airway stenosis, but its role in the palliation of advanced thyroid cancers invading the upper airway is unclear. This study examined the hypothesis that durable and replaceable silicone stents would give better results than self-expanding metallic stents.
Methods:   A retrospective analysis was conducted of consecutive patients stented for laryngotracheal obstruction due to thyroid cancer. Stenting was performed via a rigid bronchoscope when airway patency after dilatation was ≤50% of normal. Symptomatic improvement, Hugh-Jones (H-J) classification, Eastern Cooperative Oncology Group performance status (PS), and complications were analysed.
Results:   There were 37 stenotic lesions treated in 35 patients. The most common sites for these lesions were in the inclusive area extending from the cricoid cartilage to the first tracheal ring (26/37 lesions, 70%). Forty-five stents (12 silicone, 20 metallic, 13 T-tubes) were used in 43 interventions. All patients showed immediate symptomatic relief and significant improvement in both PS and H-J classifications. Critical complications were supraglottic stenosis (5/43 interventions, 12%) and, of those same five cases, stent migration was seen in all but one (4/45 implantations, 9%). As these complications occurred only in patients in whom the silicone stents had been placed in close proximity to the cricoid cartilage (5/10 patients, 50%), this emphasizes the unsuitability of silicone stents in such cases. The median survival time from stenting was 8 months. The 1-year survival rate was 40%.
Conclusions:   Airway stenting can achieve significant palliation in patients with thyroid cancer and airway obstruction. The study showed that for the most common lesions, the uncovered Ultraflex stent is associated with fewer critical complications than the silicone stents.     

Swallowing of a dynamic tracheal stent: an unusual complication

Cicatricial tracheal stenoses are mainly related to iatrogenic injury as postintubation, posttracheotomy or postoperative. Advances in airway prosthetics have provided a variety of silicone stents and expandable metal stents as a therapeutic option for tracheal stenoses. Nowadays, dynamic tracheal stents are performed prevalently for the treatment of tracheal stenosis. Four major problems are currently associated with airway stents: Mucostasis, formation of granulation tissue, infection and migration. In this report, we present a case of swallowing a tracheal dynamic stent as an unusual complication of tracheal stents.     

Newly developed biodegradable stents for benign gastrointestinal tract stenoses: a preliminary clinical trial

We developed an Ultraflex-type stent by knitting polylactic acid monofilaments. The purpose of this study was to evaluate the stent's clinical usefulness for treating benign stenoses in the gastrointestinal tract. The radial force of the biodegradable stent was compared with those of commercially available metallic stents. The measured radial force of the new biodegradable stent was higher than that of commercially available metallic stents. The biodegradable stents were applied in 2 patients with benign gastrointestinal stenoses. The first patient was a 19-year-old female with esophageal stenosis, due to drinking of caustic potash in an attempt to commit suicide. The second patient was a 75-year-old male who had a stenosis at the anastomotic site after esophageal cancer resection. In both cases, the placement of the stent was performed successfully, and the patients' complaints improved immediately after stent placement. There were no complications during stent placement. The stenosis had not recurred at the six-month follow-up examination. In conclusion, the newly developed biodegradable stents were useful in treating benign stenoses of the alimentary tract.     

Novel silicone stent to treat tracheobronchial lesions: results of 35 patients

We describe a case series of 35 patients with either benign (14) or malignant (21) tracheal stenosis who were treated using a novel silicone stent, the HCPA-1, designed to prevent migration. Between March 2001 and September 2008, 13 women and 22 men received 41 HCPA-1 stents. The median duration of stenting in benign cases was 457 days (range, 4-2,961 days). Successful stent removal with curative results was accomplished in 2 patients with tracheomalacia and 1 with post-intubation stenosis. In malignant cases, the median duration of stenting was 162 days (range, 1-1,279 days). Five patients had tumor progression with obstruction requiring repeated laser resection, dilatation, or additional stents. Two patients died due to airway obstruction despite bronchoscopic intervention. Twelve patients with malignant lesions died with the stent in place. At the end of the study, 3 patients with malignant disease remained alive; 2 were lost to follow-up. The HCPA-1 stent proved to be safe, with no severe complications during the study period, and effective in improving quality of life with relief of dyspnea.     

Screw-thread vs Dumon endoprosthesis in the management of tracheal stenosis

STUDY OBJECTIVES: A frequent complication of the widely used Dumon silicone stent is its tendency to migrate when used in tracheal stenosis. We compared the clinical efficacy and complications (including migration) of the Dumon stent with a screw-thread stent, a device with an increased stent-to-wall contact surface and, theoretically, less tendency to migrate. DESIGN: Retrospective case analysis. SETTING: Academic hospital. MATERIALS AND METHODS: Forty-six patients with tracheal stenoses (23 benign and 23 malignant) requiring the placement of 50 stents (29 Dumon and 21 screw-thread) were studied. In 26 patients Dumon stents were used, and in 20 patients screw-thread stents were used. Both patient groups had comparable clinical and stenosis-related characteristics. RESULTS: Stent insertion and follow-up were uneventful in both the Dumon and the screw-thread insertions, respectively: 62% vs 67% (not significant). There were seven migrations in the Dumon group, compared to only one migration in the screw-thread group, respectively: 24% vs 5%. This difference did not reach statistical significance (p = 0.1). All of the migrations occurred in the benign stenosis group, and none occurred in the malignant-stenosis group, respectively: 8 of 23 vs 0 of 23, p = 0.004. Within the benign-stenosis group, the Dumon stent had a significantly increased risk for migration when compared to the screw-thread stent, respectively: 7 of 13 vs 1 of 11, p = 0.033. CONCLUSIONS: The screw-thread stent and the Dumon stent are equally effective in the management of tracheal stenosis. There is a general trend toward a decreased migration rate, and a significantly lower risk for migration in patients with benign tracheal stenosis. The (less expensive) screw-thread stent may represent an attractive alternative in the management of tracheal stenosis in general, and may be preferable to the Dumon stent in treating benign tracheal stenosis.     

Elective stenting of "unprotected" left main coronary stenosis in patients without contraindication to bypass surgery]

Coronary surgery is at this point of time the standard therapy of unprotected left main coronary artery stenosis. Coronary angioplasty (PTCA) is performed only in bail out situations. The number of publications of successful percutaneous intervention in unprotected left main coronary stenosis is increasing because of increasing use of stents and ticlopidine to avoid stent-thrombosis. From 9/96 to 7/98, 13 patients with unprotected left main coronary stenosis were treated with stents. All of them were accepted by the heart surgeon for bypass surgery but were not considered to be optimal candidates due to advanced age of more than 80 years (n = 5), significant co-morbidity (n = 2) or diffuse diseased peripheral coronary segments (n = 6). Mean age of patients was 74 +/- 10 years, 9 were male, and all patients presented with angina III-IV (CCS). Mean ejection fraction was 55 +/- 15%. Localization of stenoses were classified as ostial (n = 5), middle (n = 3), and bifurcational (n = 6). One patient had stenoses both in the ostium and in the bifurcation. In all cases a PTCA of the culprit stenosis was performed prior to stent implantation. The mean diameter of the stents used was 3.3 +/- 0.3 mm and the mean length was 11 +/- 4 mm. In 6 patients a PTCA of either left anterior descendens (LAD) or right coronary artery was performed in the same session. In 4 of these patients it was followed by a stent implantation. All procedures were performed with surgical stand-by, an intraaortal balloon pump was available, but was not uses prophylactically. Stent implantation could be performed successfully in 12 out of the 13 patients (success rate 92%). In bifurcational stenoses stents were positioned with the proximal end in the left main and the distal end in the LAD. Significant injury or occlusion of the circumflex artery was not observed. In one patient with bifurcational stenosis with severe calcification it was not possible to cross the lesion with an accurate sized balloon. Trying to cross with a smaller balloon (2.5 mm) resulted in dissection of the left main coronary artery which could not be reopened again by catheter technique. This patient was transferred to the operating room under conditions of cardiopulmonary resuscitation and a bypass surgery was performed. He was dismissed from the hospital with no evidence of perioperative myocardial infarction.The mean time for follow-up was 12 +/- 7 months, all patients are still alive. In 6 patients an angiography was performed during follow-up because of suspicion of recurrent ischemia. Two patients out of these 6 had restenoses in the left main coronary artery which were re-dilated (17%). Another 2 patients had stenoses in other coronary segments and were also dilated. Thus, stenting of left main coronary artery stenoses is feasible, however, with acceptable risks and could be considered in selected patients as an alternative to coronary artery surgery.     

Serial late dilatations of expanded polytetrafluoroethylene‐covered stents in porcine aorta

Background: Covered stents may be desirable for stenting of coarctations. Objectives: To evaluate the ability of Atrium expanded polytetrafluoroethylene (ePTFE)‐covered stents to be implanted and then serially dilated to the size of the adjacent aorta during a rapid growth period in swine. Methods: Eight Yorkshire pigs (7 females) with a mean weight of 18.3 ± 0.7 kg had an Atrium ePTFE‐covered stent deployed in the descending aorta. Five of these animals also had an identical Atrium bare metal stent (BMS) control deployed in the descending aorta. All swines were recatheterized with the first dilatation of the stents to 14 mm at day 100. Four of these animals were recatheterized at day 145 and euthanized, and the remaining four swine were recatheterized with a second dilatation to 18–20 mm, 195 days after initial implantation. Results: All stents were deployed without device malfunction, and both uncovered and covered stents were successfully dilated from 10 to 11 mm to the size of the adjacent aorta (16–20 mm). There was no gradient across either type of stent on recatheterization and all stents were well sized to the native aorta. Only the size of the aorta limited the degree of stent dilatation. The Atrium covered stents consistently recoiled after maximal dilatation and required higher pressures for further expansion. Gross damage to the aorta was noted in two animals in which stents were dilated to >20% the diameter of the native aorta. In stent neointimal thickness was equivalent for both types of stent. Conclusions: Atrium ePTFE‐covered stents can be implanted at 10–11 mm and serially dilated to accommodate for rapid aortic growth. High pressure balloons are required for dilatation of ePTFE‐covered stents. Atrium covered stents exhibited more recoil and foreshortening at larger diameters. © 2008 Wiley‐Liss, Inc.     

Novel growth stent for the permanent treatment of vessel stenosis in growing children: An experimental study

Stent implantation in stenotic vessels of infants and small children is problematic because there is no ideal stent model that is small enough to be easily introduced into the infant femoral vein or artery and, at the same time, large enough to be dilated during growth to adult vessel diameters. To overcome this problem, we designed a new stent, the growth stent. This growth stent is a balloon‐expandable metal stent. Two longitudinal halves are connected with bioabsorbable sutures so that a circular stent is created. It was postulated that after absorption of the sutures the stent would not impede growth. Twenty of these stents were implanted in the aorta, pulmonary arteries, and inferior vena cava of piglets (average weight 6.9 kg). After 18 weeks (14–23 weeks) and a mean weight gain of 59 kg, none of the stented vessels showed any significant stenosis or pressure gradient, documented by angiography and catheter pullback. During fluoroscopy, the two halves of the stent were clearly separated in all animals. The growth stent has the potential to be nonrestrictive during vessel growth, and thus is a promising new device for the permanent treatment of stenotic vessels in infancy and childhood. Catheter Cardiovasc Interv 2004;62:506–510. © 2004 Wiley‐Liss, Inc.     

食管金属支架治疗125例食管狭窄和食管气管瘘临床分析

背景：食管狭窄和食管气管瘘是临床常见疾病，近年来食管金属支架逐渐成为其治疗的重要手段，并取得了良好的疗效。目的：探讨食管金属支架治疗食管狭窄和食管气管瘘的临床疗效。方法：选择125例良恶性食管狭窄和食管气管瘘患者，行内镜和x线检查以明确狭窄或瘘口的部位和性质。在x线引导下置入食管金属支架，术后密切随访观察临床疗效和并发症。结果：支架术后2周内，所有患者的吞咽困难均显著改善；食管气管瘘患者的呛咳均显著缓解，仪5例患者进流质时仍有轻微呛咳：86例(68．8％)患者术后出现胸痛，8例(6.4％)发生消化道出血，4例(3.2％)出现支架移位。术后半均随访时间为18个月。吞咽困难的平均缓解时间为7.4个月，27例恶性食管狭窄患者平均于术后6.4个月因肿瘤组织增生而导致再狭窄，8例良性食管狭窄患者平均于术后12．8个月因肉芽组织增生而导致再狭窄。38例患者有胃(或肠)食管反流表现，大多为吻合口支架或食管下段支架。7例患者出现支架移位。恶性食管狭窄患者支架术后平均存活时间为11．8个月。结论：食管金属支架能有效治疗良恶性食管狭窄和食管气管瘘，提高患者的生活质量。但支架术后再狭窄、食管功能紊乱和支架移位等并发症目前仍无法避免，且可能对支架的临床应用产生一定影响。