A long-placed vena cava filter

Abstract

The invention relates to a long-retention type vena cava filter, and belongs to the field of medical instruments. The long-retention type vena cava filter comprises a plurality of elastic supporting wires surrounding the same central axis, wherein a head end gathered bundle of the plurality of elastic supporting wires is fixed into a first end cap, and a tail end gathered bundle of the plurality of elastic supporting wires is fixed into a second end cap; each elastic supporting wires is sequentially divided into three sections in smooth transition from the head end to the tail end, including an arc portion, a first straight line portion and a second straight line portion; the first straight line portions are parallel to the central axis, the length of the first straight line portions is 2 to 5 millimeters, and included angles between the first straight line portions and the second straight line portions are 130 to 170 degrees. The long-retention type vena cava filter disclosed by the invention has the advantages of being not prone to displacement after being embedded for 3 months, having small contact areas with blood vessel walls, reducing endothelialization degree, being convenient to embed in and take out from femoral vein, and reducing operation complexity and operation risk.

Description

technical field [0001] The invention relates to a long-placed vena cava filter, which belongs to the field of medical instruments. Background technique [0002] The inferior vena cava filter (IVCF) is an implantable medical device designed to prevent pulmonary embolism caused by emboli in the inferior vena cava system. Vena cava filters can generally be divided into three categories: temporary filters, permanent filters, and retrievable filters. [0003] Although most retrievable filters are called "retrievable", because they allow a very short time window for indwelling in the body, usually 2 to 3 weeks, during this period, the risk of venous thromboembolism (VTE) or contraindication for anticoagulation in many patients still remains. If it is not completely eliminated, the retention time of the filter has to be extended, and once the specified period is exceeded, the filter is often difficult to remove due to problems such as thrombosis and intima, so it is generally not ...

AI Technical Summary

Problems solved by technology

[0003] Although most retrievable filters are called "retrievable", because they allow a very short time window for indwelling in the body, usually 2 to 3 weeks, during this period, the risk of venous thromboembolism (VTE) or contraindication for anticoagulation in many patients still remains. If it is not completely eliminated, the retention time of the filter has to be extended, and once the specified period is exceeded, the filter is often difficult to remove due to problems such as thrombosis and intima, so it is generally not suitable to remove to avoid difficult removal and newborns that tear off the covering filter. endothelial injury

[0004] Most of the retrievable vena cava filters in the prior art have an asymmetrical single umbrella structure, which improves the recovery rate of the filter to a certain extent and prolongs the recovery time window, but this type of filter is prone to sideways deviation when placed Inclined, placed for a long time, with the body's activities, it is easy to cause the perforation of the inferior vena cava, and the metal wire is also prone to breakage due to uneven force

However, the currently clinically formed filters (such as the filters of Cordis and Lifetech in the United States) have a relatively large contact surface with the inner wall of the blood vessel, endothelial cell adhesion, smooth muscle migration, and tissue-like packaging, resulting in a short recovery time window for the filter. Or it cannot be recovered smoothly, and if it is forcibly recovered, it may cause damage to the vessel wall

In addition, the geometric stability of this structure is poor, the filter is prone to displacement and inclination, and the filter rod crack and vessel wall damage are prone to occur during the recovery process.

At present, the filter of Bard Company in the United States has a long payback period. The filter has a dome made up of 8 overlapping rings, and 6 legs under it are radially conical. The upper and lower layers can capture thrombus, but there are still the following disadvantages: 1. The asymmetric complex structure increases the difficulty of operation and is prone to deflection; 2. The recovery filter must be operated from the internal jugular vein, which increases the difficulty of operation and the risk of recovery complications

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