A new self-convertible inferior vena cava filter:in vivo experimental evaluation / 中国组织工程研究

BACKGROUND:An inferior vena cava filter is an effective tool to prevent fatal pulmonary embolism. The existing filters have some shortcomings that limit their clinical application. OBJECTIVE:To evaluate the feasibility and capture efficiency of a new self-convertible inferior vena cava filter (SCF)in vivo. METHODS:L-lactide and ε-caprolactone were fused and polymerized to act as a degradable deformable switch of the filter. Medical stainless steel wire as the metal structure of the filter was combined with the degradable deformable switch to make the SCF. Eight SCFs were implanted into the inferior vena cava of eight adult Beagle dogs. The inferior vena cava angiography was performed to evaluate the release process, morphology and location of the filter. Venous angiography was performed 2 weeks later to evaluate the morphology and location of the filter and inferior vena cava patency. Detection of pulmonary embolism or other complications was performed at autopsy. RESULTS AND CONCLUSION:Eight SCFs were successfully implanted and positioned accurately with no tilt, and they were converted successfully at 2 weeks after the implantation, as assessed by the venous angiography. One of the eight SCFs migrated to the orifice of the right atrium, and caused asymptomatic inferior vena cava obstruction. The remaining SCFs were normally positioned with no tilt and local lesion or obstruction after deformation. No marked filling defect in the trunk of the pulmonary artery was shown by the pulmonary artery angiography. The autopsy report revealed that the filter arm had been endothelialized, and the inferior vena cava that was in contact with the filter arm had no obvious stenosis. Mild intimal hyperplasia, less than 1 mm in thickness, was found in the bottom of the filter arm, but it did not cause a stenosis in the lumen. No vena cava perforation, retroperitoneal hemorrhage, and injury of the surrounding viscera were found. Overall, the design of the SCF is feasible.

A new self-convertible inferior vena cava filter:in vitro experimental evaluation / 中国组织工程研究

BACKGROUND: Inferior vena cava filter is an effective way to prevent fatal pulmonary embolism. The existing filters have some shortcomings that limit the clinical application. OBJECTIVE:To evaluate the feasibility and capture efficiency of a new self-convertible inferior vena cava filter(SCF)in vitro. METHODS: The biodegradable switch was constructed of a copolymer of ε-caprolactone and L-lactide (75%/25%, PCLA75). The biodegradable switch bound together with the apices of the convertible struts to make the self-convertible filter. The deformability and capture efficiency of the filter were tested in an in-vitro flow model with three different diameters (22, 25, 28 mm). A total of 15 filters were implanted both in the vertical and horizontal positions, and the tilt angle of the filter was tested after release. To accelerate switch degradation, a lipase perfusate was injected into the flow model and refreshed every 8 hours until conversion. RESULTS AND CONCLUSION: (1) All the filters were successfully implanted without tilting, both in the vertical and horizontal positions in the three different diameter models. (2) All the 15 SCFs were converted successfully without tilting, structural damage, and displacement. (3) The capture efficiency of the SCF had significant difference between the different diameter of the models, the size of the embolus and the position of the two models (P < 0.001). The mean capture efficiency was 82.5%, and the capture efficiency exhibited a downward trend with the increase of pipe diameter, the decrease of emboli size, and the position of pipeline changing from vertical to horizontal. All these results show that the SCF is feasible and highly efficient.

Excimer laser atherectomy combined with drug-eluting balloon angioplasty for the treatment of chronic ischemia of lower limbs: preliminary results in three patients / 介入放射学杂志

Objective To evaluated the safety and feasibility of excimer laser atherectomy (ELA) combined with drug-eluting balloon angioplasty in treating chronic ischemia of lower limbs.Methods ELA combined with paclitaxel-eluting balloon angioplasty was adopted to treat chronic ischemia of lower limbs caused by arteriosclerosis occlusive disease of lower extremity in three patients.All three patients had arteriosclerosis occlusive disease of superficial femoral artery;in two of them the disease was primary occlusive lesion and in another patient the disease was in-stent re-occlusion lesion after sten implantation.Results After the treatment,the blood flow in the diseased arteries was unobstructed,the blood supply of the lower limbs was obviously improved.No procedure-related complications occurred.Two weeks after the treatment,no recurrence of ischemic symptoms was observed,the blood flow in superficial femoral artery kept unobstructed.The patients recovered smoothly.Conclusion For the treatment of chronic ischemia of lower limbs,which are caused by the primary arteriosclerosis occlusive disease of lower extremity or by the in-stent re-occlusion lesion after sten implantation,ELA combined with paclitaxel-eluting balloon angioplasty is clinically safe and feasible,although its long-term effect needs to be clarified with more studies.

Endovascular therapy for complex subclavian artery occlusive diseases / 介入放射学杂志

Objective To discuss the key points of endovascular therapy for complex subclavian artery occlusive diseases. Methods During the period from January 2012 to December 2013, a total of 92 patients with complex subclavian artery occlusive disease were admitted to Xuanwu Hospital of Capital Medical University, Beijing, China. The clinical data were retrospectively analyzed. The features of the lesions, the success rate of endovascular therapy, the use of combined approaches, the relief of symptoms after treatment, etc. were evaluated. Results The complex subclavian artery occlusive diseases could be divided into three types. Type Ⅰ: long segment of the left subclavian artery was occluded; type Ⅱ: ostial stenosis or occlusion of the right subclavian artery; and type Ⅲ: subclavian artery stenosis or occlusion was associated with the ostial disorder of the vertebral artery, or the opening of vertebral artery was affected by the subclavian artery stenosis or occlusion. The technical success rate was 82.6%. Combination use of femoral artery and brachial artery approach was employed in 27.2% of patients, which had improved the technical success rate. After the treatment the symptom improvement rate was 81.6%. Conclusion Upper limb artery approach can improve the re-canalization rate of left subclavian artery with long segment occlusion, and can ensure the accurate positioning of stent at the site of right subclavian artery opening. During the procedure of endovascular intervention for subclavian artery occlusion disease, attention should be paid to the protection of the vertebral artery.