Field of the Invention

The invention, in the field of interventional radiology, relates to a vascular plug (1) , which is released from the distal end of the microcatheter (3) to the relevant vascular lumen (5) , by pushing it with a guidewire (2) through the internal cavity of microcatheters (3) of various diameters to block blood vessels and to stop bleeding. The plug is produced by hardening bioabsorbable or biocompatible microfibrils together to form a monofilament yarn and has radio-opaque material. The front end is pointed, the body is cylindrical and monolithic; the rear end (6) , which is pushed by the guidewire (2) , comprises free microfibrils in the form of brushes. It is an easy-to-apply, effective and low-cost plug with its short, flat and space-free skeletal structure.

Known State of the Art

In interventional radiology, vascular coils/plugs, carried through catheters and flocculated according to its shape memory when released within the vessel or aneurysm, are used to stop bleeding, to prevent blood from flowing to the relevant vessels, or to ensure that vascular aneurysms are filled non-surgically and endovascularly. In bleeding or tumor embolizations, there are also procedures including injection of some materials through the catheters such as fluid mixture of particles of various micron diameters or liquid embolizing agents.

The plugs are basically released in two ways in the desired position within the vascular lumen; I . They are pushed (pushable ) through the inner cavity of the microcatheter with a guide wire so that they can not be retracted/recollected when released .

I I . After the front end of the plug attached to a carrier wire is released from the microcatheter to the vascular lumen, the rear end is detachable from the wire by various mechanisms ( electrolytic, mechanical , hydraulic, electrothermal ) according to the final decision . The advantage thereof is that i f the plug position or the helical state it takes in the space is considered to be incorrect , it is collected again into the microcatheter without leaving the attached carrier wire .

In vascular plugs , the general endovascular plugs of the previous technique can prevent intravenous blood flow and stop bleeding by taking spiral form (macrohelical , spiral or three-dimensional complex ) in the space with its superelastic metal alloy (nitinol , etc . ) skeleton in microhelical form of desired diameter and length and shape memory . When used in the treatment of aneurysm, the aneurysm cavity is filled with coils . Thus , with the increasing blood pressure , the aneurysm can not expand further, rupture of the wall and possible bleeding are prevented . In some cases , the use of multiple coils may be required . Some plugs have feathery short fibrils that trigger coagulation, or coatings that swell in case of water contact .

Vascular plugs are very useful products used to stop emergency bleeding without the need for surgery or in cases where surgery cannot be performed . However, the most important disadvantages are that they are complex and costly .

These vascular plugs are frequently used in the intervention of patients with emergency bleeding ( subarachnoid brain bleeding, respiratory bleeding, gastrointestinal bleeding, kidney bleeding, limb bleeding, etc . ) . However, disruptions occur in product supply due to the lack of domestic production and external dependence, insufficient current HPC (Communique on Health Practices) prices for material purchase.

The patent document no. US2005155610A1 may be referred as an example for the current state of the art. This document deals with a plug consisting of a bioabsorbable or biocompatible material developed for occlusion of blood vessels. The coil can be used to treat internal bleeding and aneurysm or to suppress the flow of blood to a tumor. The coil in its most general form is a hollow spiral monofilament formed by shaping from a bioabsorbable polymer. The coil is released to the desired area of the blood vessel through a catheter and can maintain its final shape after being pushed thanks to its shape memory. The inner diameter of the product in question is 0.12 mm. The smallest diameter-guidewires produced (0.012 inch=0.30 mm and 0.014 inch=0.36 mm) would not pass through the cavity. Therefore, It is understood that this coil is only released to the desired vascular lumen by pushing it through the inner cavity of the microcatheter by means of a guidewire. In an embodiment of the invention, a carcinostatic, anti-tumor agent may be inserted into the coil cavity.

Another example of the current state of the art is the patent document No. US5423849A. The document deals with a tube-shaped vaso-occlusive device obtained by knitting radio-opaque fibers to occlude blood vessels and to stop bleeding. The vascular occlusive device of the document has a tube-shaped lumen (hollow) and is released to the desired area through a catheter. The said product are coils, preferably of 0.015- 0.018 inch diameter, woven from 0.0005-0.005 inch-thick fibers. There is a suppository or fibrous center in the internal cavities.

In document US2004098023A, a vaso-occlusive device developed to stop the flow of blood through the vessel is discussed. In its most general form, the vaso-occlusive device subj ect to the said document comprises a central structure and a fibrous structure made of nanofibers attached thereto .

Another example of the current state of the art is the document No . US 9060777B1 . The document in question is a patent document about a vascular occlusive device developed for the treatment of aneurysms . In its most general form, the device of the said document consists of a wire center made of long thin metal material and a tubular outer element attached thereto on the proximal side , produced by knitting from metallic material (nitinol ) with a diameter of 0 . 001 inch or less , a length of 6- 10 cm, expandable to a diameter of 2 mm when released . It is stated in the document that al l or some of the elements constituting the aforementioned vascular occlusive device may consist of bioabsorbable and/or biodegradable material . The distal of said occlusive device ( i . e . , the remote end first released into the vessel ) is not associated with the guidewire , but rather is free while the proximal ( i . e . , the close end last released into the blood vessel ) is attached to the guidewire so that it can be retracted back . The plug has a complex structure that can be pushed into the aneurysm and retracted into the catheter i f desired without completing its final position . The purpose of use is to fill and treat aneurysmal cavities rather than stopping bleeding vessels .

As an alternative to the known state of the above-mentioned technique , a vascular plug with a pointed front end and a cylindrical , hard and monolithic body has been developed in order for it to be easily transported into the catheter and to be advanced therein . This vascular plug developed is for blocking blood vessels and for stopping bleeding, wherein the plug is easy to apply, ef fective and low-cost with a short , flat and space- free skeletal structure , the front end of which is pointed, the body part is cylindrical and the back end is brushed, which is used by pushing through the microcatheter lumen by means of a guide wire.

Detailed Description of the Invention

The invention relates to a vascular plug (1) , which is used to block blood vessels and to stop bleeding, especially in the field of interventional radiology.

An object of the invention is to develop effective and low- cost vascular plugs (1) that can fill the need and task gap between existing commercial embolizing micro-particles, and plugs .

The inventive vascular plug (1) is used similarly to routine endovascular applications of existing commercial plugs. Accordingly, the microcatheter (3) advanced through the macrocatheter (4) and the vascular plug (1) pushed by a guidewire (2) therethrough are released in the desired vascular lumen (5) . In this way, blood flow is prevented and the relevant vessel is clogged/occluded .

Bioabsorbable (biodegradable) or biocompatible microfibrils are assembled into monofilament yarns in desired diameters, and the front end is hardened with biocompatible adhesives. A short (0.5-1.5 cm) , gapless and flat skeletal structure is obtained. The forward end of the plug structure in the microcatheter (3) is pointed, the body part is monofilament and the cylindrical, the rear end (6) , which is pushed by the guidewire (2) , is in a brush-like form thanks to the microfibrils that can expand when released in the vascular lumen (5) . As such, the plug can also be released by a high- pressure liquid jet (such as saline, etc.) injected from the proximal hub of the microcatheter (3) outside the patient. The diameter of the plug is selected smaller than the inner lumen diameter of the microcatheter (3) , where it will be used together for convenience in application. The inner lumen diameter of the produced microcatheters (3) varies between 0.015 inch=0.38 mm and 0.028 inch=0.71 mm.

In one embodiment of the invention, the microfibrils comprise, polyglycolic acid, polyglactic acid, polylactic acid, polyglactin, polydioxanone, polythrimethylene carbonate, polyglecapron, glycomer, polyglitone, polyglyconate, catgut, collagen, silk, cotton, linen, etc. or a mixture thereof.

An embodiment of the invention comprises biocompatible adhesives such as cyanoacrylate derivative comprising radioopaque contrast material crystals.

Since the material component in the main form of the plug does not contain metal, it does not create a disadvantage for MR imaging. However, nitinol microfiber can be added to a variant form of the plug to give it radio-opacity and to take helical form in the vascular cavity. In this way, the length of the plug and the final helical form it gets in the vascular lumen (5) can also increase the occlusive function of the plug .

This type of vascular plug (1) is not suitable for use in aneurysms. It has been developed only for the purpose of blocking the bleeding vessel to stop bleeding.

An embodiment of the invention may also be used in combination with commercial plugs known in the art for the same purpose (to stop bleeding) .

When the plug of the invention is released, it cannot be reversed .

An embodiment of the invention has a monolithic, thin, flat, short and space-free skeleton structure with radio-opaque material to be released in the vascular lumen (5) by pushing it with a guidewire (2) through the internal cavity of a microcatheter (3) passing through a macrocatheter (4) . The skeletal structure is obtained by making bioabsorbable or biocompatible microfibrils into a monofilament yarn and hardening this yarn with biocompatible adhesive materials, so that it can be pushed through the internal cavity of the microcatheter (3) with a guidewire (2) . Said skeletal structure includes a pointed front end; a thin, gapless, short and hard body; a rear end (6) comprising free microfibrils in a brush-like form.

In summary, the invention is a vascular plug (1) for blocking blood vessels and stopping bleeding, wherein the plug is a monofilament comprising a biodegradable and/or biocompatible microfibrils and radio-opaque material, hardened in the form of a monofilament yarn, having a space-free skeletal structure extending in a direction to be released in the vascular lumen (5) by pushing it with a guidewire (2) through the internal cavity of a microcatheter (3) passing through a macrocatheter (4) . The skeletal structure includes a pointed front end advancing in the microcatheter (3) , a cylindrical body and a rear end (6) comprising free microfibers in the form of a brush, which expands when released in the vascular lumen (5) and being pushed by a guidewire (2) .

An embodiment of the invention comprises biocompatible adhesive for hardening of the monofilament yarn.

The length of an embodiment of the invention is between 0.5- 1.5 cm .

An embodiment of the invention can comprise nitinol microfiber for taking helical form in the vascular cavity.

An embodiment of the invention has a diameter of less than 0.028 inch=0.71 mm in the microcatheter (3) . Description of the Figures

Figure 1 : View of the release of the vascular plug of the invention within the catheters and the guidewire-mediated target vascular lumen Figure 2 : Perspective view of the vascular plug of the invention

Figure 3 : View of the rear end of the vascular plug of the invention

Descriptions of Reference Numbers in Figures 1 . Vascular plug

2 . Guidewire

3 . Microcatheter

4 . Macrocatheter

5 . Vascular lumen 6 . Rear end