新型可回收血管支架的设计与有限元分析

目的针对药物洗脱支架植入后引起的早期再狭窄问题,对镍钛合金血管支架进行结构上的可回收设计和生物力学分析。方法建立可回收血管支架及其回收系统的几何模型,其中支架回收部为圆台形网状结构,由4个对称分布的回收筋组成;分析支架在压握过程中的最大主应变分布、压握及自膨胀均匀性等,并对支架的回收过程进行仿真实验。结果当支架被压握至最小尺寸时,其最大应变为3.7%,不均匀性指数为0.62%;当支架自膨胀结束时,其不均匀性指数为1.31%;当1/2支架被回收进外鞘管时,最大应变为1.52%;而支架在回收过程中并未发生断裂或"卡顿"情况。结论支架应变在其安全范围之内,且支架的压握及自膨胀过程较均匀,能够被安全、顺利地回收进外鞘管中。研究结果可以为可回收血管支架的结构设计、生物力学分析和临床应用提供重要参考依据。     

Clinical remission following endoscopic placement of retrievable,fully covered metal stents in patients with esophageal achalasia

Metal stents may represent an alternative therapy in the treatment of achalasia. We therefore evaluated the effectiveness of retrievable, fully covered metal stents in patients with achalasia. Fifty‐nine patients with achalasia were treated with retrievable, fully covered metal stents. Symptoms using a global symptom score (0–10), lower esophageal sphincter (LES) resting pressure, LES relaxation, and simultaneous contraction of the esophagus were analyzed before and 1 week and 1 month after intervention. Complications and treatment outcomes were followed up at 6, 12, 18, and 24 months postoperatively. Stent placement was successful, and clinical symptoms resolved (P < 0.01) in all patients. Regurgitation, dysphagia and chest pain improved significantly (all P < 0.01). Therapy improved LES resting pressure (51.4 ± 9.7 mmHg pretherapy vs. 20.9 ± 8.1 mmHg post‐therapy), LES relaxation (58.1 ± 17.1% pretherapy vs. 84.5 ± 18.9% post‐therapy), and simultaneous contraction of the esophagus (36.1 ± 8.6% pretherapy vs. 69.4 ± 23.1% post‐therapy) 1 month after stent placement (all P < 0.01). The cumulative clinical remission rates 6, 12, 18, 24, 30, and 36 months after stent removal were 90.9%, 81.8%, 76.4%, 69.1%, 65.5%, and 49.1%, respectively. All patients tolerated stent placement. Twelve patients (25.5%) complained of substernal pain and five (10.6%) had substernal burning. Stents migrated in four patients (8.5%). Insertion of retrievable, fully covered metal stents is an effective and safe treatment in patients with achalasia.     

A prospective long-term study of 220 patients with a retrievable vena cava filter for secondary prevention of venous thromboembolism

BACKGROUND: The immediate and long-term clinical events associated with the placement and removal of a retrievable filter (ALN filter; ALN Implants Chirurgicaux; Ghisonaccia, France) remain largely unknown. METHODS: This was a prospective cohort study with an 18-month follow-up. All consecutive patients scheduled for placement of an ALN filter between April 1999 and June 2005 in the Radiology Department of our hospital were included. RESULTS: During the study period, placement of an ALN filter was indicated in 220 patients (mean age, 70.8 years), who were followed up for a median duration of 338.5 days (range, 1 to 561 days); 148 patients (67.3%) completed the 18-month follow-up. No patients were unavailable for follow-up. All patients had an acute or past venous thromboembolism. Main indications were recurrent venous thromboembolism despite adequate anticoagulation therapy (10.9%), transient bleeding event (21.8%), definitive contraindication for anticoagulant therapy (26.8%), or obligation to stop anticoagulant therapy due to major surgery, major trauma, or invasive procedure (37.7%). Filter insertion was successful in 98.6% of patients and resulted in an immediate complication in 11.8%. The median duration of filter implantation was 166 days (first to third quartiles, 34 to 478 days). Meanwhile, 17.0% (37 of 217 patients) had at least one venous thromboembolic event. Filter retrieval was attempted in 25.3% of patients after a median of 51 days (range, 6 to 352 days); removal was successful at the first attempt in 92.7% of patients. CONCLUSIONS: The filter could be easily inserted and successfully removed up to 1 year after insertion. Its safety and efficacy in preventing pulmonary embolism should be properly assessed in a randomized study.     

Fully covered,retrievable self-expanding metal stents (Niti-S) in palliation of malignant dysphagia: Long-term results of a prospective study

Abstract

Background. In the palliative treatment of malignant dysphagia, fully covered, retrievable metal stents are not commonly used, mainly due to the high risk of migration. Therefore, we performed a prospective study to evaluate the clinical efficacy of a fully covered, retrievable self-expanding metal stent (Niti-S). Method. Between October 1998 and February 2009, 100 consecutive patients with malignant esophageal obstruction treated with the fully covered Niti-S stent (Niti-S, Taewoong Medical, Seoul, South Korea) were included. Data collected contained functional outcome, feasibility of endoscopic stent retrieval, recurrent dysphagia, complications, and survival. Result. At 4 weeks after stent placement, dysphagia significantly improved in all patients (p = 0.000). Recurrent dysphagia occurred in 19 of 100 patients treated with Niti-S stents (19%) mainly due to tumor overgrowth (7/100, 7%), stent migration (6/100, 6%), and food impaction (6/100, 6%). Endoscopic stent retrieval was successful in all the attempted 17 patients (17/100, 17%) – 7 overgrowth, 6 stent migration, 2 stent degradation, and 2 severe pain. Major complications were 2 hemorrhage, 2 severe pain, and 1 tracheal compression (5/100, 5%), and minor complications were 10 retrosternal pain and 7 symptomatic gastroesophageal reflux (17/100, 17%). After a median follow-up of 142 days, 97 patients had expired. There was no stent-related mortality or 30-day mortality. Conclusion. The fully covered, retrievable Niti-S stent has proved its effectiveness for palliation of malignant dysphagia and feasibility of endoscopic retrieval. We estimate its dog-bone shaped flanges at both ends and it being completely covered provide good resistance to migration and overgrowth.     

Optimising daytime deliveries when inducing labour using prostaglandin vaginal inserts

Objective: To determine induction start time(s) that would maximise daytime deliveries when using prostaglandin vaginal inserts.

Methods: Women enrolled into the Phase III trial, EXPEDITE (clinical trial registration: NCT01127581), had labour induced with either a misoprostol or dinoprostone vaginal insert (MVI or DVI). A secondary analysis was conducted to determine the optimal start times for induction by identifying the 12-h period with the highest proportion of deliveries by parity and treatment.

Results: Optimal start times for achieving daytime deliveries when using MVI appear to be 19:00 in nulliparae and 23:00 in multiparae. Applying these start times, the median time of onset of active labour would be approximately 08:30 for both parities and the median time of delivery would be the following day at approximately 16:30 for nulliparae and 12:00 (midday) for multiparae. Optimal start times when using DVI appear to be 07:00 for nulliparae and 23:00 for multiparae. Using these start times, the median time of onset of active labour would be the following day at approximately 04:00 and 11:50, and the median time of delivery would be approximately 13:40 and 16:10, respectively.

Conclusions: When optimising daytime deliveries, different times to initiate induction of labour may be appropriate depending on parity and the type of retrievable prostaglandin vaginal insert used.     

可回收支架对内镜下食管全周黏膜剥离术后食管狭窄的预防作用

【摘要】 目的 探讨食管环周内镜下黏膜剥离术（ESD）后预防食管狭窄的最佳方法。方法 选择24只贵州小型猪,将其分为ESD对照组、 试验组1（局部糖皮质激素黏膜下注射组）和试验组2（内镜下食管支架植入组）,每组8只。选择猪食管中段即距门齿24～29cm进行环周ESD剥离。试验组1在食管环周ESD术后采用地塞米松注射液03mg/点环周注射;试验组2在食管环周ESD术后采用可回收覆膜支架植入,1月后胃镜下取出食管支架。ESD术后1周,2周,1月, 3月,6月评估三组试验猪的存活、体重变化、食管狭窄及胃镜通过情况。结果 ESD对照组在ESD术后1月食管明显狭窄,但部分胃镜镜身尚能通过。试验组1术后1月发生狭窄,但狭窄程度较ESD对照组轻。试验组2术后1月未发生狭窄。术后3月比较,ESD对照组狭窄明显增加,胃镜通过率仅约20%,试验组1狭窄也明显增加,胃镜通过率约40%,而试验组2虽发生狭窄,但胃镜通过率达到80%。术后存活比较：与ESD对照组比较,试验组1在术后1月无差异,术后6月存活明显增加;而试验组2在术后1月、3月和6月都明显增加（P＜005）。术后体重比较：术后1月,ESD对照组及试验组1体重减轻,但试验组1无对照组减轻明显,试验组2体重明显增加;术后3月和6月比较,试验组2较试验组1试验猪体重明显增加（P＜005）。结论 食管环周ESD术后局部地塞米松注射可减轻术后狭窄,并增加存活,然而狭窄和死亡率仍较高。食管环周ESD术后覆膜支架植入,并于1月后取出能明显减少食管患者ESD术后的狭窄,并明显增加存活,效果优于局部地塞米松注射。     

Clinical experience with retrievable vena cava filters: results of a prospective observational multicenter study

BACKGROUND: Retrievable inferior vena cava (IVC) filters offer the attractive possibility to be definitive or to be removed when they become unnecessary. OBJECTIVE: The purpose of this study was to evaluate the efficacy and the likelihood to remove the retrievable IVC filter ALN. METHODS: A total of 30 patients (13 males and 17 females, mean age 57 +/- 15 years) underwent placement of ALN filters. Indications for implantation were acute venous thromboembolism (VTE) with a contraindication to anticoagulation in 26 cases (86%), primary prophylaxis after major trauma in two cases (7%) or before surgery in two patients with very high thromboembolic risk (7%). RESULTS: The filter was successfully placed in all patients. After a median follow-up of 18.2 months, there were three cases (10%) of trapped emboli within the filter, one case (3%) of asymptomatic migration of the filter toward the heart and two patients (7%) had deep vein thrombosis (DVT) recurrences. ALN retrieval was attempted through transjugular approach in 18 patients (60%) and the maneuver was successful in 14 of them (78%); when the decision of removal was taken more than 3 months after the implantation, the retrieval was possible only in four of eight patients (50%). The median implantation period was 123 days (range: 30-345). CONCLUSIONS: The present study shows the efficacy of ALN filter; it also demonstrates the feasibility and safety of retrieval after a medium-term period of placement. Removal after 3 months after implantation can be unsuccessful and maximum implantation time requires further studies.     

Retrievable Gunther Tulip inferior vena cava filter: Experience in 317 patients

The aim of our study was to assess our experience with the retrievable Gunther Tulip (GT) inferior vena cava (IVC) filter, with regard to its insertion, efficacy, ease of placement and retrieval, and associated complications. Between November 2001 and October 2005, 322 GT filters were placed in 317 patients. Insertion indications included the following: pulmonary embolus (PE) prophylaxis in trauma patients (n = 232), PE prophylaxis in perioperative patients (n = 27), PE prophylaxis in moribund intensive care unit patients (n = 22), recent PE (n = 48), extensive deep venous thrombosis (n = 66), contraindication to anticoagulation (n = 63), anticoagulation complication (n = 8) and deep venous thrombosis with failed anticoagulation (n = 8). Some patients had more than one indication for caval filter placement. Two hundred and five attempted retrievals have been carried out, with 15 failures. Our successful retrieval rate is 92%. Nineteen filters were originally inserted permanently. There have been three minor complications associated with insertion and five with retrieval. The mean time from filter insertion to attempted retrieval was 76.95 days. The ideal filter implantation time gives the patient the benefit of PE protection, while avoiding the long‐term risks associated with caval filters. Although GT retrieval times have lengthened considerably, our data suggest that this is at the expense of successful retrieval rates.     

Initial Australian experience with the recovery inferior vena cava filter in patients with increased risk of thromboembolic disease

Inferior vena cava (IVC) filters are an alternative treatment in venous thromboembolism where there are contraindications to anticoagulation. There are, however, concerns about the long-term safety of permanent IVC filters. Often, the period of risk from anticoagulation therapy is short, which supports the use of non-permanent IVC filters. In this series, 54 Recovery Filters (Bard, Tempe, AZ, USA) were placed since its approval for use in Australia in March 2004 (approved for removal up to 160 days after insertion). The most common indication for filter placement in this series was established thromboembolic disease with a temporary contraindication to anticoagulation. Twenty-two filters were successfully retrieved without complication. In one case, it was not possible to retrieve the filter because of extensive contained thrombus. No complication was experienced at filter placement or retrieval; however, a fatal complication occurred as a result of filter migration. Mean time from placement to retrieval was 48 days (range 7-90 days). We describe methods we found useful at filter retrieval to overcome filter tilting.     

Individual Lithium Disilicate Crowns in a Full‐Arch,Implant‐Supported Rehabilitation: A Clinical Report

This clinical report presents the clinical outcome of a maxillary full‐arch implant‐supported fixed rehabilitation with lithium disilicate reinforced glass ceramic monolithic crowns opposing a mandibular metal‐acrylic implant‐supported fixed rehabilitation in a 62‐year‐old woman. Eight implants were successfully placed (four maxillary, four mandibular), and no complications occurred in the postoperative or maintenance periods. Six months after delivery, the maxillary and mandibular prostheses were found to be clinically, biologically, and mechanically stable, and the patient was satisfied with the esthetics and her ability to function. Although the present indications for the use of lithium disilicate are still restricted to tooth‐borne restorations, it is possible to successfully rehabilitate edentulous patients through implant‐supported fixed prostheses using lithium disilicate reinforced glass ceramic monolithic crowns.