Patent Publication Number: US-2016220236-A1

Title: Method for closing a blood passage of a blood vessel

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device for percutaneously closing apertures in walls of blood vessels and vascular prosthesis. Such apertures are made to perform diagnostic examinations, or to position surgical instruments for endovascular interventions. The invention relates also to a device for treating blood vessels haemorrhagic, dilatative or dissecting pathologies or arteriovenous malformations. 
     In particular, the device can be used at the end of such a diagnostic procedure as arteriography or coronarography, or of such an endovascular intervention as angioplasty, stenting or embolization, which require a percutaneous puncture of an artery for positioning an introducer sheath in the vascular bed. In specific exemplary embodiments, the device can be used for treating pseudoaneurysms, for arterials or venous embolization, or for treating dissections of arterial walls. 
     BACKGROUND OF THE INVENTION 
     Many diagnostic and therapeutic procedures provide the step of percutaneously introducing instruments and/or catheters through vascular entry sites. To this purpose, introducer sheaths are used, i.e. substantially cylindrical valved cannulas, which are removed only at the end of the procedure. 
     At the moment of the removal of the introducer sheath, the entry site, i.e. a hole in the wall of the artery, remains open and must be immediately closed to avoid bleeding. For closing the hole and stopping the blood outflow at the removal of the introducer sheath, a well-known technique provides exerting a compression force at the entry site, first manually and then by means of a bandage or by application of a weight. The compression force causes also a local reduction of the arterial blood pressure proximate to the entry site, which first allows natural haemostasis process to start, and which then avoids that sudden blood pressure changes or movements of the patient causes the entry site to open again. Once bleeding has been stopped, the repair of the entry site is completed within a few days. For instance, in the case of a femoral entry site of a patient who has normal coagulation parameters, the closing treatment of the entry site by a means of compression usually lasts between 8 and 12 hours, during which the patient must remain motionless. 
     Complications may sometimes arise such as bleeding, hematomas, pseudoaneurysms, in particular in the case of patients whose blood hardly coagulate due to a disease or to an a anticoagulation treatment, or in the case of patients who have a vascular prosthesis (by-pass) at the inguinal region. 
     In some cases, even by prolonging the compression, the entry site cannot be closed, and a surgical treatment is necessary, which may involve further risks, discomfort, prolonged period in bed and resources waste. Furthermore, in case of obese patients, the adipose layer that is located between the skin and the vascular entry site reduces the efficiency of the compression. 
     Moreover, an entry site on a vascular prosthesis that is made of plastic (Dacron, PTFE, etc.) cannot heal by the natural repair processes of an artery, and, on the contrary, it can only be closed by formation of a true plug made of blood that, after flowing out of the opening, coagulates through the tissues that surround the prosthesis, under the assistance of the compression force. In this case, therefore, the risk that bleeding may start again when the compression force is released is much higher, which suggests to avoid entry sites of vascular prosthesis; on the other hand, this is particularly desirable when dilatative or stenosing diseases have to be solved upstream or downstream of the prosthesis. 
     Systems are also known for closing percutaneous entry sites, which comprise a suture means and/or a mechanical closing means, such as grafts or plaques, which may be associated with a haemostatic liquid. Such systems reduce the average treatment time. However, the introduction of objects into the blood vessels may cause thrombosis-related ischemia, embolism, arterial wall laceration, sensitization, allergic reaction. Furthermore, the mechanical closure devices require a highly skilled operator, and/or the work of further assistant operators. Therefore, these techniques do not provide a valid alternative to the traditional techniques. 
     Systems are also known for closing the entry site of an introducer sheath with exclusive use of a haemostatic liquid, in particular collagen, to form clots that are involved in a natural coagulation mechanisms; however, the haemostasis process is slow, and complications may arise such as blood suffusion, bleeding, pseudoaneurysms. 
     Quickly-setting haemostatic liquids are also known, which would be well-suited for forming a strong and flexible closure at the entry site. Liquid of this kind, such as internal use surgical glues, have not been used so far for closing percutaneous vascular entry sites, since: 
     for injecting a haemostatic liquid in a narrow space like that is available at a percutaneous access, it is preferable to use small cross section ducts, to limit the amount of liquid to be used and to avoid the production of hardened lumps under the skin; similar ducts are easily closed by the quickly-setting haemostatic liquids that quickly harden by reacting with blood, lymph or other biological material that enters the duct during the puncture, which makes the injection impossible to carry out; 
     it is very difficult to release a quick setting haemostatic liquid in a pure state in an operation region where blood under pressure is present. The methods that use quick setting surgical glues provide a dilution of the glue, but this prolongs the hardening time; 
     with well-known techniques, and also under echographic control, it is difficult to release such pure quick setting haemostatic liquid proximate to a vascular entry site without the risk of injecting it into the blood vessel, with such complications as thrombosis or embolisms. For this reason, in order to use a quick setting haemostatic liquid, and at the same time avoid an echographic control, it is important to establish as precisely as possible the position of the point where the liquid must be released. 
     The echographic control may not be always available when this kind of intervention is performed, because it requires experienced operators and in any case it requires more than one operator for closing the entry site. 
     To this purpose, in EP0941697 a device is described for bringing a haemostatic substance proximate to a percutaneous entry site. The device comprises a cylindrical body that is coaxially coupled to the introducer sheath that slides along it until a “sensation” is felt that the device has reached the artery. Then the haemostatic substance is released. The device is mounted on the introducer sheath before positioning it in the blood vessel; therefore, it prevents the use of the whole length of the introducer sheath, which obliges a portion of the introducer sheath to be left outside of the skin, differently from what happens in the normal procedure. This causes an unsteady positioning of the introducer sheath, which is particularly critical in the case of obese patients, where the distance between the skin and the blood vessel is higher than in normal patients. Furthermore, the large transversal size of the device hinders the movement through the tissues, and “digs” an enlarged space about the introducer sheath in which both the released haemostatic liquid and the blood can accumulate without contributing to the entry site occlusion. In any case, the device is not adapted to treat a quick-setting liquid, because the delivery mouth may be easily clogged. 
     Various systems have been proposed to provide a liquid that is adapted to make an occlusion in an operation region. 
     In particular the device of US2008/45700 is adapted to treat bleeding diseases, for example, in the stomach and in the intestine, but it cannot be used neither for an endovascular intervention, nor for closing an arterial entry site. Due to its high reactivity, a cyanoacrylate material would immediately polymerize when brought into contact with the blood, which would reduce the passage through the catheter, or even clog it, in such a way that the release of a significant amount of surgical glue would be impossible. 
     US patent application 2001/000616 relates to a method for applying a blood-based pro-coagulating substance proximate to a vascular entry site through a hole of a catheter to be inserted through an introducer sheath. For positioning the hole immediately out of the artery, the operator slowly withdraws the catheter until the blood stops flowing out of the distal end of it. This is a rough method, by which the risk may arise of injecting the procoagulating substance into the vessel; for the same reason, the method and the apparatus cannot be used to safely release surgical glues, which are not cited in the patent application. 
     International patent application WO 02/089675 relates to a device and to a method for blocking an arterial entry site of a patient who has been treated with anticoagulant therapy. This invention relates however to the use of blood that is taken from the patient itself and is treated with a substance that is an antagonists of the anticoagulant treatment, whereas it does not deal with surgical glues or similar liquids. Furthermore, the document does not provide precise indications about the way the liquid is supplied at the entry site. In any case, the device cannot be used to release a quick-setting surgical glue proximate to an entry site, because the glue would come into contact too early with the nearby biological fluids which would block the device; furthermore, it does not allow an operator to determine the point of delivery, unless an echographic control is provided. 
     U.S. Pat. No. 3,548,825 relates to a syringe for injecting a mixture of two components that are contained in respective receptacles of the syringe, which allows mixing the liquids at the moment of the injection. Similarly to any well-known syringe, a similar device does not allow providing a quick setting, in particular, of a haemostatic liquid in a pure state, at an entry site or in an operation region of an endovascular surgery. 
     Concerning the endovascular surgery, such as an embolization of arterial or venous districts, or the treatment of arterial walls dissections, the problem often arises of covering a long distance between the entry site, which is normally made in the artery of the arm or in the femoral artery, and the operation region. When the use is desirable of a pure quick setting surgical glue, which would have a maximum efficiency and application speed, the problem arises of conveying the glue through a long duct, and of preventing at the same time any risks of contact between the glue and the blood until the remote vascular district is reached where the intervention must be made. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an occlusion device for haemostasis of arterial entry sites and for endovascular treatment, which uses a quick setting haemostatic liquid, for example a surgical glue, preventing the haemostatic liquid from prematurely hardening in the device and causing it to block. 
     It is, furthermore, an object of the present invention to provide a device for releasing such a liquid at an operation region in a pure, i.e. undiluted state. 
     It is a particular object of the present invention to provide such a device for bringing this liquid close to an arterial entry site for occluding the opening that results from the extraction of an introducer sheath, stopping the bleeding after the extraction of a catheter introducer sheath. 
     It is a particular object of the present invention to provide such a device that prevents such a liquid from flowing into an artery through the opening, without using echographic or radiographic control means. 
     It is still a particular object of the present invention to provide such a device for closing percutaneous entry sites of vascular prosthesis, in particular, of by-pass prosthesis made of Dacron or of PTFE. 
     It is another particular object of the present invention to provide such a device for bringing such a liquid to a prefixed vascular district for carrying out an endovascular intervention without modifying the quick hardening properties of the liquid, assuring therefore a complete reaction, and limiting the possibility of spreading in vascular remote districts. 
     It is another object of the present invention to provide such a device that encounters a minimum resistance while crossing tissues to reach the point of release of the liquid in a procedure of occlusion of a vascular entry site, using as far as possible a channel formed around the introducer sheath. 
     It is also an object of the present invention to provide such a device that can be easily handled by an operator. 
     These and other objects are achieved by a device for causing a release of a surgical glue in an operation region in a patient&#39;s body for blocking a flow of blood of an artery, the device comprising a duct having an inlet port and an outlet mouth for said surgical glue, said duct adapted to move through a biological medium in the patient&#39;s body from an opening on a skin plane of said patient to said operation region in such a way that, once said operation region has been reached by said duct, said outlet mouth is in said operation region and said inlet port remains outside of said opening in said skin plane, said inlet port in use hydraulically connected with a source of said surgical glue and with a pressurizing means that can be operated by an operator for applying an injection pressure on said surgical glue and for causing: 
     an outflow of said surgical glue through said duct, and 
     said release of surgical glue at said operation region through said outlet mouth, 
     the main feature of the device is that a liquid contact preventing means is provided that is associated to said duct, said liquid contact preventing means adapted to impede in said duct a contact of said surgical glue with said biological medium before said outflow, in particular a contact of said surgical glue with blood of said patient. 
     This way, the liquid contact preventing means does not allow that the blood, or other biological material coming from the operation region, can penetrate into the duct and interact with the surgical glue before the injection. In fact, such penetration would cause the inconvenience of a premature hardening of the surgical glue inside the duct, which would immediately clog the duct and would make the release impossible. The present invention allows therefore the use of surgical glues that are particularly reactive with blood and with other biological fluids, such as cyanoacrylic glues, which can be easily transferred into the operation region in an undiluted state. Such highly reactive glues are well-suited for internal use, but their application is presently limited by the above-described drawbacks. 
     In particular, said liquid contact preventing means comprises a backflow preventing means that is adapted to prevent a material of said biological medium from penetrating into said duct. 
     In particular, a coupling means is provided which is adapted to couple said duct with an elongated introducer sheath that can extend in use between said opening on said skin plane and a vascular entry site, said introducer sheath having an outer surface, and said coupling means adapted to engage in use with the outer surface of said introducer sheath. This way, when the operation region is a neighbourhood of an arterial entry site, or of an entry site of a vascular prosthesis, which is engaged by an introducer sheath, the invention allows immediately to block bleeding when said introducer sheath is withdrawn from said entry site, and said surgical glue is at the same time injected onto said introducer sheath from said outlet mouth. In fact, due to said coupling means, said outlet mouth is in a close proximity of said introducer sheath. Therefore, by extracting the introducer sheath from the entry site, together with the device, a channel is left free, which is filled with the surgical glue, preferably under the action of a manual compression exerted on the skin, which cleans the introducer sheath during the extraction, and causes the glue to remain immediately outside the entry site. 
     In particular, said outlet mouth is arranged between said duct and said outer surface of said introducer sheath, and said backflow preventing means is provided by said coupling means, said coupling means suitable for keeping said outlet mouth in a one-way fluid tight contact against said outer surface of said introducer sheath, such that said outlet mouth detaches from said introducer sheath only when said pressurizing means is operated. In other words, a backflow preventing means may be provided by the coupling means itself, which is made in such a way that the outlet mouth is kept tight against the introducer sheath, such that the introducer sheath keeps the outlet mouth closed until an injection pressure is created by the operator. 
     Advantageously, said coupling means is a sliding coupling means, i.e. it comprises a slide portion of said duct associated with a driving portion of said introducer sheath. 
     For example, the driving portion is a groove along which the duct slides, the duct having a shape suitable for firmly engaging with the groove. Advantageously, the groove has an undercut portion with which the duct firmly engages. In alternative, the driving portion is a protrusion of the introducer sheath, and the slide portion is a groove with a shape that corresponds with the protrusion. 
     Advantageously, said coupling means comprises a short tube that is coaxially coupled with said elongated introducer sheath. In this case, the driving portion is the introducer sheath itself, which is substantially cylindrical, and the slide portion is the short tube itself. 
     Preferably, the short tube has a thickness that is set between 40 and 300 micron, in particular, between 40 and 70 micron. Advantageously, the duct has a tapering surface at the outlet mouth, such that its transversal size decreases along the front portion, i.e. along the portion that in use is arranged most proximate to the entry site. In particular, a smooth connection is provided within the duct and the short tube, in order to create a minimum resistance. Preferably, the duct extends along the short tube, and a front portion of the short tube is left free from the duct, said front portion having a length that is preferably set between 2 and 4 mm. Such features of the short tube and of the duct, separately considered, assist the movement through the tissues between the skin plane and the operation region, in particular the small thickness of the short tube allows using the zone of the tissues that surrounds the introducer sheath, which is already modified by the introducer itself, and where the resistance to the forward movement of the short tube is lowest. 
     In alternative, said outlet mouth is laterally arranged with respect to said duct. This way, it is possible to move the duct through the tissues without any risk of clotting the outlet mouth. 
     Preferably, said outlet mouth and said short tube are such that said surgical glue is released in an annular narrow space that is defined between said short tube and said introducer sheath, such that said surgical glue reaches said operation region through said annular narrow space. In these conditions, the surgical glue works in two ways: 
     as already described, in a portion of a channel that is most proximate to the entry site, it interacts with the blood that flows out of the entry site, thus stopping the bleeding; 
     in the portions of the channel that are more distant from the entry site, it engages mainly with such other biological materials as fat, lymph, periadventitial tissues, sticking together the walls of the channel and sealing the channel. 
     As already said, the operation region is a region between the skin and the entry site of the blood vessel, where the biological tissues have been modified by the introduction and by the permanence of the introducer sheath. The surgical glue, in particular a low viscosity one, tends naturally to flow inside this lower resistance region, about the introducer sheath. In this case, the short tube advantageously assists the release of the surgical glue on the introducer sheath itself in such a way that, when the introducer is withdrawn, the surgical glue is left exactly in the operation region, which limits the dispersion through the nearby tissues. This way, less surgical glue is required, which reduces the probability of: 
     surgical glue introduction into the circulatory system through the entry site; 
     formation of gross hardened glue lumps under the skin. 
     The device may have a one-way fluid tight means at a rear end of said short tube, which is arranged in use proximate to said skin plane, said one-way fluid tight means suitable for avoiding the surgical glue from leaking through a corresponding rear end of said narrow space, said one-way fluid tight means comprising, in particular, a sealing ring that is arranged inside said narrow space. The one-way fluid tight means further assists preferential sliding of the surgical glue, once it has been released from the duct, towards the entry site, which in turn assists the interaction with the blood that flows out of the entry site when the introducer sheath is removed. 
     Advantageously, said sliding coupling means can be actuated while said introducer sheath engages said entry site, such that it is possible to couple said duct with said introducer sheath after arranging said introducer sheath in said entry site. 
     Preferably, said sliding coupling means that can be actuated while said introducer sheath engages said entry site comprises a short tube that has a longitudinal cut that extends from a front end of said short tube, said front end oriented in use towards said operation region, to a rear end of said short tube, such that by closely aligning and reciprocally compressing said short tube and said introducer sheath, said short tube forms a snap fit with said introducer sheath and a sliding coupling is obtained between said short tube and said introducer sheath. 
     Advantageously, the introducer sheath and the short tube have a substantially cylindrical shape, and a minimum width portion of the longitudinal cut has a width set between 2/9 and 4/9 of the short tube diameter. Preferably, the short tube is made of a resilient material such as polyethylene or polypropylene. 
     Therefore, the short tube can be eventually coupled with the introducer sheath in an easy way, and allows closing the entry site in an effective way. In particular, it is possible to carry out a percutaneous procedure and then the haemostatic procedure at the patient&#39;s bed. The snap fit coupling has the advantage of allowing at the same time the duct to be fastened to the introducer sheath and to slide with respect to the introducer sheath, and the outlet mouth of the duct to be in contact with the surface of the introducer sheath, such that the thin wall of the short tube also works as a membrane. In fact, the pressure against the thin short tube exerted by the fluids and by the nearby tissues keeps the short tube in tight contact with the introducer sheath, and only an injection pressure exerted while injecting the glue can exceed this pressure and cause the surgical glue to flow into the channel that has been created by the introducer sheath. Furthermore, the annular short tube assists the outlet flow of the surgical glue along the surface of the introducer sheath, in particular, towards the entry site of the blood vessel. 
     Advantageously, a block means is provided for blocking a movement of said duct with respect to said introducer sheath. This allows a surgical glue dose to be released at a safe distance from the entry site, thus preventing the hardening material from entering the blood vessel, without any echographic control needed. 
     Advantageously, the block means is arranged at a distance from the outlet mouth set between 3 mm and 12 mm, preferably between 3 mm and 5 mm. This distance is enough to effectively and safely release the surgical glue, both in the case of a normal patient and in the case of an obese patient. In fact, it has been observed that the femoral artery, where entry sites are normally made, may be at a distance from the skin plane that ranges from about 6 mm to more than 30 mm. The angle of incidence between the puncture direction and the artery can be selected in such a range that the distance between the puncture of the artery and the puncture of the skin plane is always greater than 8 mm. Before the introducer sheath is withdrawn, the surgical glue is prevented from entering the artery by the introducer sheath itself; after the extraction of the introducer sheath, the surgical glue is subject to the pressure that is exerted by the operator on the skin for releasing the glue in the channel. At the same time, the arterial pressure causes the blood to flow out of the entry site, towards the channel. The high reactivity of the surgical glue causes a quick local hardening of the outflowing blood front, which helps to prevent dispersion of the surgical glue through the nearby tissues. 
     Advantageously, the block means is arranged at a distance from the front end of the duct that is set between 6 mm and 15 mm, preferably between 6 mm and 8 mm. For reasons similar to the above-mentioned ones, this prevents the end of the duct from being placed too close to the entry site, both in the case of an obese patient, and in the case of a normal patient. 
     Advantageously, the surface of the duct has a line, i.e. a marker, which is traced distally with respect to the block means, for signaling a point at which the movement of the sliding duct along the introducer sheath must be blocked, outside of the skin of a particularly thin patient, in particular the marker is located at a distance set between 3 mm and 5 mm from the outlet mouth. 
     Thanks to the sliding coupling between the duct and the introducer sheath, the operator, with one hand and without the need to coordinate the movement of more than one limb, can cause the duct to slide and can block it when the block means abuts, and can operate the pressurizing means by one finger, thus causing the release of the surgical glue in the operation region, at a safe distance from the entry site of the artery. In the short time between the release and the hardening of the surgical glue, the surgical glue is prevented from entering the artery by the introducer sheath, which is still inserted in the entry site, as well as by the arterial pressure; the high speed with which the glue locally interacts with the biological means, avoids its dissolution through the nearby tissues. 
     Preferably, said block means is arranged integral to said duct at a distance from said outlet mouth such that said outlet mouth is at said predetermined distance from said skin plane when said block means abuts against said skin plane. 
     In alternative, said block means is adapted to abut against a wall of said artery at said entry site, and said outlet mouth is arranged at a predetermined distance from said block means, in order to make an operator aware that said outlet of said duct is ready for releasing said surgical glue proximate to said entry site. 
     The outlet mouth may be arranged above or laterally with respect to the duct. 
     Said backflow preventing means may also comprise a check valve that is arranged at said outlet mouth, said valve comprising a fixed part that is fixed with respect to said duct and a movable part that is movable with respect to said fixed part, wherein, when said pressurizing means is operated, said movable part changes its position from: 
     a closed position, in which said release of surgical glue is hindered, to 
     an open position, in which said injection pressure causes said release of surgical glue at said operation region. 
     In alternative, said liquid contact preventing means comprises: 
     a liquid retaining means for retaining a barrier liquid inside said duct; 
     a liquid outflow means that can be operated by said operator for causing an outflow of said barrier liquid through said duct, 
     such that: 
     said barrier liquid interposes between said surgical glue and said outlet mouth, and such that 
     by operating said liquid outflow means and said pressurizing means, said barrier liquid flows out of said outlet mouth before said surgical glue, such that said surgical glue is substantially undiluted when it is released at said operation region. 
     The duct may be selected from the group comprised of: 
     a conventional needle, to be used for example in the haemostasis of arterial entry sites, pseudoaneurysms or small aneurysms; 
     a catheter, to be used for reaching remote operation regions through an endovascular path, said remote operation regions located far from an entry site. 
     Finally, during the injection into a blood vessel in which the blood flows, the barrier liquid, which is released first, is washed away by the blood flow; therefore, when the surgical glue is released, the high reactivity of the surgical glue with the blood is substantially unchanged, which ensures that the interaction is carried out to completion locally. 
     Advantageously, the device comprises a container for said barrier liquid, said container selected from the group comprised of: 
     a portion of said duct; 
     a receptacle that in use is hydraulically connected to said duct. This feature assists safe operation, since it reduces the possibility of mistakes that might otherwise be made when selecting a barrier liquid at the moment of the use; moreover, the feature allows a more practical operation. 
     The receptacle may have an inlet port and an outlet port, preferably with respective connecting means to connect the receptacle with the container of the device and with the duct. Advantageously, the receptacle is available in sizes responsive to the barrier liquid need, which is in turn responsive to the distance of the operation region from the device, in particular endovascular interventions require much more barrier liquid than what is needed to treat an arterial entry sites. 
     Preferably, said container contains said barrier liquid, in particular, a barrier liquid selected from the group comprised of: 
     a saline solution; 
     a glucose solution; 
     distilled water; 
     a liquid contrast agent. 
     The use of a liquid contrast agent as a barrier liquid allows using a radiographic means for displaying the point that has been selected for releasing the surgical glue, since surgical glues cannot be seen by a radiographic means. On the other hand, not all the vascular zones can be shown by an echographic means, due to the presence of air or of bones, which causes unfeasibility of many interventions under echographic control, for example thoracic, abdominal or cerebral interventions. Many surgical glues, in particular cyanoacrylate glues, can in any case be detected by an echographic means and can therefore be used under echographic control, if possible, and a saline solution may then be used as the barrier liquid. 
     Advantageously, said liquid outflow means can be operated independently from said pressurizing means. This way, the operator can arrange the duct up to reach the operation region by the outlet mouth, without suffering the effects of blood pressure, or, in any case, the effects of the resistance offered by the tissues while they are crossed by the duct: in fact, the liquid that is retained inside the duct behaves as an integral part of the duct and the rest of the device. In particular, a blood backflow or suction may not occur while the duct is being positioned. 
     Preferably, the device comprises a protection means for avoiding accidental operation of said pressurizing means before said outflow of said barrier liquid. 
     Preferably, the device comprises a sealing member for isolating said barrier liquid in said container, wherein said sealing member can be removed or broken by an action selected from the group comprised of: 
     operating said liquid outflow means; 
     operating said pressurizing means; 
     connecting said duct with said container of said barrier liquid; 
     a combination of such operations. 
     This way, the surgical glue is prevented from mixing with the barrier liquid before its application, which would decrease its efficiency. The duct that contains the barrier liquid can be for example a needle or a catheter whose inlet port has a seal that can be broken by joining the catheter with the container, and whose outlet mouth has a manually removable seal. 
     Advantageously, said liquid contact preventing means comprises, furthermore, a locking means that is selected from the group comprised of: 
     a locking means of said liquid outflow means, 
     a locking means of said pressurizing means; 
     such that a backward movement of said liquid outflow means and of said pressurizing means, respectively, is prevented; 
     a combination of said locking means. 
     This feature assists the operator while positioning the duct that retains the barrier liquid, since the operator would otherwise be obliged to apply a force for contrasting the backpressure exerted by the blood and the resistance due to the friction, but without causing a release of the surgical glue until the positioning is completed. In this case, a protection means is preferably provided for avoiding accidental operation of the liquid outflow means. 
     The device can also comprise a further receptacle that contains said surgical glue, wherein, in particular, said surgical glue comprises a cyanoacrylate, more In particular, a cyanoacrylate that is selected from the group comprised of: N-butyl-2-cianoacrylate and 2-octyl-2-cianoacrylate. These compounds give origin to highly biocompatible and particularly flexible polymers, which have been successfully used to reconstruct damaged tissues. The device according to the invention allows to widen the use of the above-mentioned surgical glues to percutaneous endovascular interventions, such as embolizations of blood vessels, treatments of arteriovenous malformations or of small aneurysmatic diseases, for example of small cerebral aneurysms, arterial dissections, and the like; furthermore, it allows their use in the haemostasis of arterial entry sites. In particular, in this case, the cyanoacrilates quickly react both with the blood and with other biological liquids that are present in the operation region, hardening the periadventitial tissues and the fat surrounding them, substantially sticking such materials on the wall of the artery, and creating at the entry site an acrylic polymer matrix, which incorporates the above-mentioned biological materials, and which works as a plug that is firmly adherent to the wall of the artery. The quick formation of the matrix stops the blood outflow and allows the completion, in an independent way, of the natural repair processes of the arterial wall, which are no longer disturbed by the blood outflow through the entry site. Such substances as the cyanoacrilates provide therefore an occlusion system that is new with respect to well known occlusions systems, which, on the contrary, form plugs or clots that are involved in the normal coagulation mechanisms, and which, for this reason, may cause the above mentioned complications. 
     In particular, the device comprises a double syringe which, in turn, comprises: 
     an internal syringe that comprises a first piston that one-way fluid tightly slides inside a first cylinder, said first cylinder having a base with a portion that comprises said frangible seal and is opposite to said first piston; 
     an external syringe that comprises a second cylinder and said internal syringe that one-way fluid tightly slides in said second cylinder, said second cylinder having a base that is opposite to said internal syringe with a tail portion, said tail portion having an outlet hole, and a tip member that is oriented towards the inside of said second cylinder and is adapted to break said frangible seal when said base of said first cylinder approaches said base of said second cylinder, wherein said internal syringe provides said further receptacle for said surgical glue and said first piston provides said pressurizing means, 
     wherein said external syringe provides said receptacle for said barrier liquid and said liquid outflow means which can be operated independently from said pressurizing means,
 
wherein a means is provided for mechanically locking said first syringe at a final position within said second cylinder and said first piston at a predetermined starting position within said first cylinder,
 
wherein preferably a cap is provided which is releasably connected with said first cylinder in order to provide said protection means for avoiding accidental operation of said pressurizing means.
 
     According to a further aspect of the invention, the above-mentioned objects are achieved by a device for closing a percutaneous entry site of a blood vessel, in particular, an entry site of an artery or of a vascular prosthesis, said entry site engaged by an elongated introducer sheath, the device comprising a duct and a sliding coupling means that is adapted to couple said duct with said introducer sheath, said duct having an outlet mouth, said duct adapted to convey a dose of a surgical glue and to release said dose through said outlet mouth in an operation region at a predetermined distance from the skin plane close to said operation region, said dose of a surgical glue adapted to make an occlusion that prevents a bleeding from said entry site when said introducer sheath is withdrawn from said entry site, the main feature of the device being that the device comprises a block means for blocking a movement of said duct with respect to said introducer sheath, wherein said block means is arranged integral to said duct at a distance from said outlet mouth such that said outlet mouth is at said predetermined distance from said skin plane when said block means abuts against said skin plane. 
     The above-mentioned objects are achieved also by a method for blocking a flow of blood of an artery to cause a release of a surgical glue in an operation region in a patient&#39;s body, said method providing the steps of: 
     prearranging a duct that has an inlet port and an outlet mouth for said surgical glue; 
     inserting said duct through an opening on a skin plane of said patient; 
     advancing through a biological medium of the patient&#39;s body until said operation region is reached, in such a way that, once reached said operation region, said outlet mouth is in said operation region and said inlet port remains outside of said opening in said skin plane; 
     hydraulically connecting said inlet port with a source of said surgical glue and with a pressurizing means that can be operated by an operator for applying an injection pressure on said surgical glue; 
     operating said pressurizing means causing an outflow of said surgical glue through said duct and said release of surgical glue at said operation region through said outlet mouth; 
     the main feature of said method is that a step is provided of prearranging a liquid contact preventing means that is associated to said duct, said liquid contact preventing means adapted to impede in said duct a contact of said surgical glue with said biological medium before said outflow, in particular, a contact of said surgical glue with blood of said patient. 
     The operative steps of the method work to carrying out the device according to the invention, as above described. 
     In particular, before said step of prearranging a liquid contact preventing means, a step is provided of 
     coupling said duct with an elongated introducer sheath that is arranged between said opening on said skin plane and a vascular entry site. 
     Preferably, said step of advancing is carried out by causing a translation on said introducer sheath of said duct slidingly coupled on said introducer sheath. 
     Advantageously, said outflow is carried out towards said introducer sheath such that said surgical glue is released and flows along said introducer sheath. In particular, said surgical glue is released in an annular narrow space that is defined between said short tube and said introducer sheath such that said surgical glue reaches said operation region through said annular narrow space. 
     Advantageously, said method provides a step of prearranging a block means integral to said duct, said block means adapted to engage with said skin plane during said step of advancing, said step of advancing stopped when said block means abuts against said skin plane. 
     In alternative, said method provides a step of 
     prearranging a liquid retaining means for retaining a barrier liquid in said duct; 
     selecting a barrier liquid; 
     introducing said barrier liquid into said duct; 
     prearranging a liquid outflow means for causing an outflow of said barrier liquid through said duct; 
     operating said liquid outflow means, 
     such that said barrier liquid interposes between said surgical glue and said outlet mouth, and such that by operating said liquid outflow means and said pressurizing means, from said outlet mouth firstly a release of said barrier liquid occurs and then said release of surgical glue occurs, such that said surgical glue is substantially undiluted when it is released at said operation region. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be made clearer with the following description of an embodiment thereof, exemplifying but not limitative, with reference to the attached drawings wherein: 
         FIGS. 1 and 2  show a perspective view and a cross sectional view of a device according to an exemplary embodiment of the invention, wherein a coupling means is provided with a catheter introducer sheath that has a short tube that is co-axial to the introducer sheath; 
         FIG. 3  shows the device of  FIGS. 1 and 2  that is coupled with an introducer sheath, which engages a vascular entry site; 
         FIGS. 4 and 5  show a perspective view and a cross sectional view of a device according to another exemplary embodiment of the invention, in which the duct comprises a needle; 
         FIGS. 6 and 7  show a perspective view of a device similar to the devices of  FIGS. 2 and 4 , in which the short tube is slidingly coupled and to snap fitted with an introducer sheath at the end of an endovascular procedure; 
         FIG. 8  is a perspective view of a particular of the device of  FIG. 7 ; 
         FIG. 9  shows the device of  FIG. 8  mounted on an introducer sheath, and have a rear one-way fluid tight means; 
         FIG. 10  shows a generic device  3  coupled with an introducer sheath, which in turn engages an arterial entry site; 
         FIGS. 11 and 12  are a views of a detail of the duct of a device according to the invention, with an exemplary embodiment of a backflow preventing means, that has a check valve which is shown, respectively, in a closed position and in an open position; 
         FIGS. 13 and 14  are Figs. similar to  12  and to  13 , referring to an exemplary embodiment of the check valve; 
         FIGS. 15, 16 and 17  show a detail of a device according to the invention, with an exemplary embodiment of a sliding coupling means between the duct and an introducer sheath, and of the backflow preventing means of the duct; 
         FIGS. 18, 19 and 20  are Figs. similar to  FIGS. 15-17 , referring to an exemplary embodiment of a backflow preventing means and to a sliding coupling means between the duct and an introducer sheath; 
         FIG. 21  shows a device similar to the device of  FIG. 6 , comprising, furthermore, a blocking means for preventing the duct from moving with respect to an introducer sheath; 
         FIGS. 22 and 23  are similar devices to the device of  FIG. 7 , wherein a block means is provided according to two different exemplary embodiments; 
         FIG. 24  diagrammatically shows a device similar to the devices of  FIGS. 21-23 , which is coupled with an introducer sheath, which in turn engages an arterial entry site; 
         FIGS. 25 to 31  show diagrammatically how to use of the device shown in  FIGS. 22-24 ; 
         FIG. 32  shows a device according to an exemplary embodiment of the invention, wherein a duct is provided which has a means for retaining an amount of barrier liquid that can be released before the surgical glue, in the case of the figure, for clogging a vascular entry site; 
         FIGS. 33 and 34  are two perspective views of a detail of a device according to the invention, that is adapted to release a barrier liquid before the surgical glue, for clogging a vascular entry site; 
         FIG. 35  shows a perspective view of a detail of an exemplary embodiment in alternative of the device of  FIGS. 33 and 34 ; 
         FIGS. 36 to 38  show a succession of closure operations of an arterial entry site by means of the device of  FIGS. 33 and 34 ; 
         FIGS. 39 to 41  show diagrammatically a succession of treatment operations of a pseudoaneurysm directly connected to an artery, by means of the device of  FIG. 32 ; 
         FIG. 42  diagrammatically shows a treatment of a pseudoaneurysm that is connected to an artery by a small duct by the device of  FIG. 32 ; 
         FIGS. 43 and 44  show diagrammatically an embolization of a blood vessel by a device according to a further exemplary embodiment of the invention, in which the duct is a catheter adapted to move along an endovascular path in a patient; 
         FIG. 45  diagrammatically shows a treatment of an endoleak after application of an endoprosthesis about an aneurysm; 
         FIG. 46  shows a double syringe according to the invention, which is in alternative to the syringe shown in  FIGS. 32, 41 and 42 ; 
         FIGS. 47 to 49  show the operation of the double syringe of  FIG. 46 . 
     
    
    
     DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS 
     With reference to  FIGS. 1, 2 and 3 , a device  10  is described according to a first exemplary embodiment of the invention, for closing an entry site  2  in a blood vessel  1 , or in a vascular prosthesis  1  ( FIG. 3 ). A substantially cylindrical catheter introducer sheath  3 , engages entry site  2 . Device  10  ( FIG. 1 ) comprises a duct  11  that has at one end an inlet port  12  that is associated with a luer-lock connection  17 , or other connection suitable for connecting a source, not shown, of a surgical glue  9 , for example a receptacle of a syringe. In the description, reference is made to a surgical glue, still remaining that the device can be advantageously used with any quick setting haemostatic liquid. At the opposite end, instead, an outlet mouth  18  ( FIG. 2 ) is provided for surgical glue  9 . For carrying out the haemostasis, outlet mouth  18  must be located at an operation region  4  ( FIG. 3 ). A short tube  13 , with a substantially cylindrical or slightly conical shape, and shorter than duct  11 , is arranged integral to duct  11  along a generatrix of it, at the end of duct  11  opposite to the end of inlet port  12 , short tube  13  is open at its two ends  14  and  15 , which are respectively the rear end and the front end, and is coupled, in use, with introducer sheath  3  ( FIG. 3 ), providing in this way a coupling means of duct  11  with introducer sheath  3 . 
     Outlet mouth  18  ( FIG. 2 ) is arranged between duct  11  and the outer surface  8  of introducer sheath  3 , and the coupling between short tube  13  and introducer sheath  3  is made in such a way that outlet mouth  18  is kept into tight contact against outer surface  8  of introducer sheath  3 , and that outlet mouth  18  detaches from outer surface  8  only when an operator, using a means provided by the device, applies an injection pressure to surgical glue  9 , causing the release of surgical glue  9  from duct  11  into operation region  4  (FIG.  3 ) through an annular narrow space  16  ( FIG. 2 ) that is formed between short tube  13  and a portion of outer surface  8  of introducer sheath  3 . This way, short tube  13  provides a backflow preventing means, which serves to prevent any contact of surgical glue  9  with a biological material  7  ( FIG. 3 ) that device  10  crosses while approaching outlet mouth  18  to operation region  4 . 
     The coupling of duct  11  with introducer sheath  3  can be a slidable or a fixed one, according to whether short tube  13  can slide or not along the outer surface of introducer sheath  3 . In the latter case, device  10  is positioned with outlet mouth  18  in the operative region since the beginning of the endovascular procedure, together with introducer sheath  3 , whereas in the former case it is preferably slided towards the operation region  4  at the end of the procedure, i.e. when the introducer sheath must be withdrawn, in order to prevent bleeding from entry site  2 . To assist device  10  sliding in the patient&#39;s body, front end  15  ( FIG. 1 ) of the short tube, and front end  15 ′ of the duct  11  have a tapered shape. Short tube  13  and duct  11  preferably form one piece that is obtained by moulding. 
       FIGS. 4 and 5  show a perspective view and a partial cross sectional view, respectively, of a device  20  according to another exemplary embodiment of the invention, in which duct  11 , which is integral to short tube  13  ( FIGS. 1 and 2 ), is replaced by a duct  21 , in particular, by a duct that is made by a syringe needle that is tightly inserted in a connecting tail portion  22  of short tube  13 , such that outlet mouth  18  is located at a passage  29  between the inside of short tube  13  and connecting tail portion  22 . Connecting tail portion  22 , and therefore duct  21 , forms an angle  26  with short tube  13 , which is preferably set between 10° and 20°. Duct  21 , in particular if it comprises a syringe needle, or a metal capillary tube, is flexible, and can therefore be permanently bent as desired by the operator, according to specific needs. Also in this exemplary embodiment, short tube  13  provides both a backflow preventing means and a coupling means between the duct and the introducer sheath. 
       FIGS. 6 and 7  show a perspective view of two devices  30  and  40  that differs from devices  10  and  20 , respectively, in that the short tube  33  has a longitudinal cut  32  from the end  14  to the opposite end  15 , along the generatrix of short tube  33  that is located opposite of duct  11  with respect to the axis  31  of short tube  33 , which is more clearly shown in the detail view of  FIG. 8 . As shown in  FIG. 9 , longitudinal cut  32  has preferably an increasing width, proceeding from rear end  14  to front end  15 , with a minimum width s of about ⅓ of the diameter of introducer sheath  3 , which forms a snap fit with short tube  33  about introducer sheath  3 , in such a way that a sliding connection is obtained. This way, device  30  can be applied at the end of the diagnostic or interventistic procedure for which the entry site to blood vessel  1  has been made. 
     Independently from whether longitudinal cut  32  is present or not, sealing means may be provided for avoiding that surgical glue  9  flows out of annular narrow space  16  ( FIG. 2 ) through rear end  14  of short tube  33 , which is oriented towards the skin  6  ( FIG. 3 ). In this exemplary embodiment, the one-way fluid tight means comprises a sealing ring  37  ( FIG. 9 ). Still to assist a surgical glue flow through front end  15  of short tube  33  towards entry site  2 , the cross section of the one piece comprising the duct and the short tube increases from the front end to the rear end, a part of the cross sectional increase due to the tapering surface at front end  15  of duct  11  and to the local thickening  24  of the wall of short tube  13  or  33  ( FIGS. 5 and 6 ). 
     Further embodiments of the backflow preventing means, in alternative to the embodiment of devices  10 ,  20 ,  30 ,  40 , are shown through  FIGS. 11 to 14 . These figures reproduce partial views of devices  50  and  60 , in which a backflow preventing means is provided by check valves  55  and  65  at outlet mouth  18  of duct  11 ; check valves  55  and  65  comprise respective fixed parts  53  and  63  and movable parts  54  and  64 . Movable parts  54  and  64  are kept in the closed position of  FIGS. 11 and 13  by the pressure P 1  that the tissues of the operation region  4  ( FIG. 4 ) exert outside the walls of duct  11 ; at the moment of the injection of the surgical glue contained in duct  11 , an injection pressure P 2  exerted on the liquid by an operator through a means of the device, not shown, overcomes the pressure P 1  and brings movable parts  54  and  64  in the open positions of  FIGS. 12 and 14 , and surgical glue  9  is released. 
     Further embodiments of the coupling means, in particular, of the sliding coupling means, between duct  11  and introducer sheath  3 , in alternative to the embodiments of devices  10 ,  20 ,  30 ,  40 , are shown through  FIGS. 15 to 20 . These figures reproduce partial views of devices  70  and  80  in which a duct  71  or  81  has a slide portion that slidingly engages with respective driving portions  77  and  87  of introducer sheath  3 . In particular, in device  70  duct  71  itself can slide as a sliding portion within a driving portion provided by a longitudinal groove  77  of introducer sheath  3 . Longitudinal groove  77  has a shape suitable for retaining duct  11 , for example by means of an undercut portion, not shown. In device  80 , a duct  81  has a slide portion  82  that can slide along a longitudinal groove  87  of introducer sheath  3 ; the slide portion of duct  41  is then connected to a rear tubular portion by a connecting portion  84 . 
     In devices  70  and  80  a backflow preventing means is provided by the connection between duct  71  or  81  and introducer sheath  3 , which is made in such a way that an outlet mouth  73  or  83  is positioned between duct  11  and introducer sheath  3 , and that the outlet mouth is kept into tight contact against introducer sheath  3  by pressure P 1  exerted by the tissues of operation region  4  ( FIGS. 16 and 19 ); at the moment of the injection of surgical glue  9 , an injection pressure P 2  exerted on the liquid by an operator through a means of the device, not shown, overcomes the pressure P 1  and locally detaches duct  11  from introducer sheath  3 , in such a way that outlet mouths  73  or  83  are opened, and surgical glue  9  is released ( FIGS. 17 and 20 ). 
     Also in the devices of  FIGS. 11-20 , above described, the connection between duct  11  and introducer sheath  3  can be a fixed connection or a sliding connection along introducer sheath  3 . 
       FIG. 21  shows a device  90 , according to an exemplary embodiment of the invention, wherein a block means is provided against skin plane  6 , which comprise an abutment  94  that is arranged at a distance b from the outlet mouth, the distance b set between 3 and 12 mm, whereas the distance d of abutment  94  from front end  15  is set between 6 mm and 15 mm, such that, when abutment  94  hits skin plane  6 , the outlet mouth safely releases surgical glue  9 , without any risks of inlet into the blood vessel through entry site  2  ( FIG. 10 ). This distance is the same both in the case of a normal patient, and in the case of an obese patient. In fact, the angle  89  that is defined between the direction of introducer sheath  3  and the local direction of a blood vessel  1  ( FIG. 24 ) may be selected in a range of values that allows compensating the difference of thickness h of the tissues between skin plane  6  and blood vessel  1 , leaving unchanged the thickness  8  that must be crossed for positioning the point of release of the surgical glue at the operation region  4 . In the case of particularly thin patients, a marker  96  can be traced on the surface of duct  11  at a distance set between 3 mm and 8 mm from the outlet mouth, for signaling to the operator the point at which the sliding movement of duct  11  along introducer sheath  3  must be blocked. 
       FIGS. 22 and 23  are partial views of devices in which duct  21  is made as it is in devices  20  and  30  of  FIGS. 4 and 6 , and in which the block means has an exemplary embodiment that is an alternative to the one that is shown in  FIG. 21 . In  FIG. 23 , the block means  97  is far smaller than in  FIG. 21 , whereas the block means  98  of  FIG. 22  are made only about connecting tail portion  12 . 
       FIGS. 25 to 31  describe how to use a device according to the invention, for closing a vascular entry site  2 , which is engaged by an introducer sheath  3 , in particular a device  90  that has a block means. A dose of a surgical glue  9  is prepared in a conventional container, not shown, for example a syringe, which is connected with duct  11  of device  90  by a fitting  17 , for example a luer-lock fitting, such that duct  11  can receive the surgical glue. Device  90  is arranged proximate to introducer sheath  3  with short tube  13  closely aligned to introducer sheath  3  against which it is pressed, in such a way that a sliding coupling can be established ( FIG. 25 ). This coupling is tight, in order to prevent the blood and other organic material that is present between the skin  6  and entry site  2  from penetrating into duct  11  when device  90  slides along introducer sheath  3  towards entry site  2  ( FIG. 26 ), and until the surgical glue receives an injection pressure. As shown in  FIG. 26 , short tube  13  is slided along the introducer sheath towards skin plane  6  and then below it, until abutment  94  hits skin plane  6 . Outlet mouth  18 , which is made at the inner surface of the short tube ( FIG. 2 ) is located then at a distance b from skin plane  6 , which is set between 3 and 12 mm ( FIG. 26 ). Through a pressurizing means for applying an injection pressure on the surgical glue  9 , for example through the walls of the container, the operator produces an injection pressure on the surgical glue pushing it through duct  11  and outlet mouth  18  ( FIGS. 2 and 27 ) against the surface of introducer sheath  3 . Surgical glue  9  travels between short tube  13  and introducer sheath  3 , evenly distributing itself along the surface of the latter, as shown in  FIG. 29 , and is partially released at operation region  4 , where it spreads preferentially in a zone that is immediately around introducer sheath  3 , where the cohesion of the tissues is weakened by the presence of introducer sheath  3 , without casually dispersing through the nearby tissues. This allows limiting the amount of surgical glue that is needed for closing entry site  2 , with economic benefits, less formation of hardened liquid lumps under the skin and higher safety against the inlet of surgical glue into blood vessel  1 . Then, the operator compresses with a finger  57  skin  6  near the percutaneous entry site ( FIG. 28 ) and, while maintaining this compression, withdraws device  90  through skin  6 . The compression assists first disengaging surgical glue  9  from the surface of introducer sheath  3  and its release in a channel  25  that is left behind by the extraction of device  90 ; a few further minutes of compression ( FIG. 30 ) are necessary to assist a rear portion  59  of channel  25  to close owing to the surgical glue that interacts with the tissues that are crossed by the introducer sheath, in particular fat, fascia and lymph, incorporate such material into a matrix that sticks together the walls of the channel, sealing it. In a front portion  58  of channel  25 , proximate to entry site  2 , surgical glue  9  interacts with the blood, with the periadventitial tissues and the wall of blood vessel  1  creating a true plug that is firmly adherent to the wall of blood vessel  1 . Below this plug the natural reparative processes of the wall of blood vessel  1  will be carried out to completion in the following days until a full restitutio ad integrum is achieved. The cyanoacrilate-based surgical glues, in particular, react much more quickly with blood than with the other biological material, which immediately stops the bleeding. 
     With reference to  FIG. 32 , a device  100  is described according to a further exemplary embodiment of the invention, in which the contact preventing means for avoiding any contact between surgical glue  9  and biological medium  7  to be crossed for achieving operation region  4  comprises a liquid retaining means for keeping a barrier liquid  5  inside duct  41 . Device  100  can be used for the haemostasis of entry site  2  of blood vessel  1 , which is engaged by catheter introducer sheath  3 . More in detail, device  100  comprises: 
     a syringe  51  that comprises a piston  44  and a cylinder  45 , which define a container  103  where a dose of surgical glue  9  is arranged; cylinder  45  has a base  114  opposite to piston  44  with a through hollow tail portion  112 , such that the outlet of glue  9  is possible, and the opposite base where a gripping portion  111  is mounted which assists handling of syringe  51 , and provides a support to a protective cap  62 ; 
     a duct, in particular, a needle  41 , which has an inlet port  42  and an outlet mouth  43 , for conveying an outflow of surgical glue  9  between container  103  and operation region  4 ; piston  44  provides a pressurizing means for applying an injection pressure on surgical glue causing it to flow out of the duct. An amount of a barrier liquid  5 , for example a saline solution, is arranged inside needle  41 , and is contained between seals, not shown, which close outlet mouth  43  and inlet port  42  of duct  41 . In particular, the seal of outlet mouth  43  can be manually removed, whereas the seal of inlet port  42  is broken by inserting needle  41  into tail portion  112 . Piston  44  has a portion, for example the sealing portion  110 , which offers an abutment to a locking means  79  that is fixed inside cylinder  45 , therefore piston  44  cannot be withdrawn beyond a predetermined starting position. This way, saline solution  5  cannot flow back up in the duct due to the advancing movement through tissues  7  and under the blood pressure, in particular, the arterial pressure, allowing an operator to position device  100  with its outlet mouth  43  in an operation region  106 , by pushing gripping portion  111  or cap  62 , without contact of the blood with the surgical glue before and during the initial releasing step; the surgical glue is then released by pushing piston  44 , and reaches operation region  106  substantially undiluted. In alternative to locking means  79 , to avoid backflow of barrier liquid  5 , a seal can be provided, not shown, which closes the hole of tail portion  112 , and which is broken when surgical glue  9 , which is contained in container  103 , receives an injection pressure P 2 , by pushing piston  44 ; 
       FIGS. 33 to 35  are partial perspective views of a device  120  according to another exemplary embodiment of the invention, in which the use of a barrier liquid, which is enclosed in a duct  91 , is still provided for avoiding the contact of the surgical glue with the biological means, and in which a coupling means with an introducer sheath  3  is provided coaxially to duct  91 , which has a substantially cylindrical short tube  93  that slides along introducer sheath  3 . Device  120  comprises, furthermore, a syringe  51  ( FIG. 32 ), and duct  91  has two seals that closes an inlet port, not shown, and an outlet mouth  99  for retaining the barrier liquid. 
     In particular, the seal of the inlet port is broken by inserting tail portion  112  of syringe  51  ( FIG. 32 ) into the inlet port, thus obtaining an outer seal, for example by a means of luer-lock fittings. Similarly to the case shown in  FIG. 32 , barrier liquid  5 , which is contained inside duct  41 , comes into contact with surgical glue  9  that is present in container  103 , however only a slight mixing may occur due to the small size of the interface that is created between the two liquids and to the short time that is left between the break of the seal of the inlet port  92  and the release of surgical glue  9  in operation region  4 . 
     Furthermore, short tube  93  ( FIG. 34 ) may have a longitudinal cut  95  along one of its generatrices that is located opposite to the duct  93  with respect to the axis  61  of short tube  93 . Longitudinal cut  95  allows the operator to clasp short tube  93  to introducer sheath  3  at the end of an percutaneous interventions, by simply aligning and compressing it onto introducer sheath  3  along cut  95 . 
     As shown in  FIG. 36 , the operator then causes short tube  93  to slide along the outer surface  8  of introducer sheath  3  by pushing with his hand on gripping portion  111  or on cap  62  of syringe  51  ( FIG. 32 ). During the sliding movement, barrier liquid  5  is retained in duct  91 : in fact, despite the arterial pressure, barrier liquid  5  cannot flow back towards cylinder  45  due to locking means  79  ( FIG. 32 ), as already described. Furthermore, cap  62  prevents piston  44  from being accidentally operated. 
     Short tube  93  has a front surface  66 , which abuts against the wall of artery  1  at a point  67  ( FIG. 37 ) proximate to entry site  2 . The position of outlet mouth  99  is then such that, when front surface  66  abuts upon blood vessel  1 , the surgical glue which is expelled from outlet mouth  99  is released just before entry site  2 . At the moment of the abutment, the operator stops sliding device  120  and pushes, advantageously with the same hand, on piston  44  for causing the outflow of the barrier liquid that is contained in duct  91  and then the outflow of surgical glue  9  through outlet mouth  99 ; at the end, the operator withdraws introducer sheath  3  and duct  91 , and produces a manual compression  68  ( FIG. 38 ) upon skin plane  6  above entry site  2 , for some minutes. A matrix  61  is then formed which consists of surgical glue  9 , blood, other liquid and tissues, in particular, fat  69 ; the matrix remains on the surface of blood vessel  1 , and closes entry site  2 . Surgical glue  9  seals furthermore, the channel left in tissues  7  that have been crossed by the introducer sheath, after its extraction. 
     Due to duct  91  integral to slide  93 , the risks of releasing hardening material into blood vessel are limited, without any echographic control being needed. 
     Duct  91  has preferably a closed and tapered front end  72  ( FIG. 33 ) in order to assist the movement of the duct through the tissues, according to the direction  34  towards entry site  2 ; similarly, front surface  66  of short tube  93  is rounded, i.e. it has a convexity  76 , still according the direction  34 , to prevent injuries to blood vessel  1  upon contact between short tube  93  and blood vessel  1 . Outlet mouth  99  is laterally or above arranged on duct  91 , thus limiting the risks of clotting due to tissues  7  that are crossed during the positioning movement of duct  91 . Similarly, short tube  93  has a convexity  74 , and a connection  75  with duct  91 , to assist its extraction at the end of the haemostatic procedure. 
     With reference to  FIGS. 39 to 42 , the use of device  100  is described for treating a pseudoaneurysm  85  that is directly connected to an artery, or one  86  that is connected to an artery through a small duct ( FIG. 42 ), i.e. formations that are defined by tissue  7  around blood vessel  1 , and that pulsate due to the blood  23  ( FIG. 39 ) that enters and exits through a direct passage  38 , or a duct  39 . In the case of a pseudoaneurysm that is directly connected to an artery  85 , the procedure provides a compression  121  upon skin plane  6  above the blood vessel upstream with respect to pseudoaneurysm  85 , and then a compression upon skin plane  6  above pseudoaneurysm  85  until pseudoaneurysm  85  is completely deflated and shrunk on the wall of blood vessel  1  ( FIG. 42 ), after a needle  123  has been inserted which allows blood  23  to flow out of the aneurysm to prevent the walls from being broken due to the compression. Afterwards, preferably under echographic control, device  100  is guided through tissues  7 : since needle  41  is stably filled with saline solution, and piston  44  cannot be withdrawn, due to previously described locking means  79 , or to an equivalent means, neither an inlet nor an early contact of blood or of other biological liquids may occur with the surgical glue, thus preventing solidification within needle  41  and blocking of device  100 ; for the same reason, the surgical glue is released in a pure state into shrunk pseudoaneurysm  85 , where it reacts completely and creates a matrix with the tissues which is suitable for blocking the passage  38 , without any dissolution of surgical glue into blood vessel  1  or through tissues  7 . Compression  121  upon skin plane  6  is then interrupted, and what remains of pseudoaneurysm  85  is subsequently naturally reabsorbed. 
     Similarly, in case of pseudoaneurysm  86  that is connected to an artery by a small duct ( FIG. 42 ), the procedure provides a compression  121  for blocking blood supply through the duct  39 ; preferably, a dose of surgical glue is released in duct  39  for definitively clogging it; pseudoaneurysm  86  is then aspirated percutaneously, and what remains of the tumefaction, which is no longer supplied with blood, is left free, and is subsequently naturally reabsorbed. In this case is much clearer as the surgical glue would react quantitatively in duct  39  or in aneurysm  86 , to avoid entry in blood vessel  1  and hardens embolizing remote vascular zones; this is possible if the particularly reactive surgical glue achieves substantially pure the zone of the operation, which is made possible by the device according to the invention. 
     With reference to  FIGS. 43 and 44 , a device  130  is shown according to an exemplary embodiment of the invention in which the duct  141  is a catheter filled with a barrier liquid. Catheter  141  is adapted to move through the blood vessels, under echographic or radiographic control, for achieving with an outlet mouth  149  an endovascular operation region, in particular, a section of a blood vessel  140  to be embolized. Device  130  may comprise, for example, a syringe  51 , which comprises a reservoir for surgical glue, as well as a pressurizing means for applying an injection pressure on such surgical glue. As in the case of the treatment of the pseudoaneurysm of  FIG. 42 , the surgical glue must react exclusively in the operation region of blood vessel  140 , to prevent hardening material from being washed away by the blood stream and from being spread in remote vascular districts, with the consequent risks. The amount of barrier liquid is defined by the volume contained in catheter  141  between the entry site through the skin of the patient, not shown, and the operation region of blood vessel  140 . 
       FIG. 45  diagrammatically shows an endoleak that can be treated by the technique for treating an aneurysm  250 . The technique provides tightly arranging an endoprosthesis  251  about the aneurysm, such that a continuity is created between the sections  252 ,  253  and  254  of the blood vessels that are interested by aneurysm  250 , and provides furthermore excluding aneurysm  250  from a direct blood flow. Inside aneurysm  250 , however, the lumbar arteries s  255 ,  256 ,  257  remain pervious, and can maintain a flow of blood through aneurysm  250 . This phenomenon is known as type II endoleak. In particular, arteries  255  and  256 , in which blood pressure is higher than the internal pressure of aneurysm  250 , change the normal direction of the blood flow and push the blood into aneurysm  250 , whereas artery  257 , which is at a lower pressure, drains this blood from aneurysm  250 . This way, a pressure remains in the aneurysm, which may lead to bleeding. For eliminating the supply of blood by the lumbar arteries, it is possible, using the device according to the invention, to prick percutaneously aneurysm  250  and cause a quick setting surgical glue to reach the terminal of the lumbar arteries. A slow setting glue would be immediately drained by lumbar artery, and would cause an embolization with subsequent medullary ischemia or an ischemia of the muscular districts to which blood is distributed. With the device according to the invention, it is possible to bring a quick setting glue, for example a cyanoacrylic glue, to the terminals  258  in a pure state, substantially maintaining its reactivity, such that the glue completely reacts in the operation region without the phenomena of dissolution above described may take place. 
     An exemplary embodiment  140  of devices  100 ,  120  and  130  comprises a double syringe  52  and any ducts selected from the group comprised of ducts  41 , 91 , 141 , or any other which is adapted to retain a barrier liquid. This exemplary embodiment is shown in  FIG. 46 , with the detail of double syringe  52 . Double syringe  52  comprises an internal syringe  150  and an external syringe  170 . Internal syringe  150  comprises a piston  151  that one-way fluid tightly slides within a cylinder  152 , which has a base  153  with a frangible portion  154  opposite to piston  151 . External syringe  170  comprises a cylinder  172 ; internal syringe  150 , which one-way fluid tightly slides within cylinder  172 , works as the piston of external syringe  170 . A protection cap  157  is provided which prevents contact with piston  151 , for sliding internal syringe  150  within cylinder  172 , and for avoiding at the same time accidental operation of piston  151  of syringe  150  itself. Preferably, cap  157  is pushed within cylinder  172  by arranging the thumb of a hand on cap  157 , and other two fingers of the same hand opposite to a gripping portion  164 , and then pushing the thumb towards the other two fingers that do not substantially move. The base  173  of cylinder  172 , which is opposite to internal syringe  150 , has a tail portion  174  that can be engaged with the inlet port of the duct of the device, not shown; tail portion  174  has a through hole  175 , which allows the liquid to be conveyed through cylinder  172  of the duct, and a tip member  176  oriented towards the inside of cylinder  172 , the tip member adapted to break frangible portion  154  when base  153  of cylinder  151  approaches base  173  of cylinder  172 , during a sliding movement of syringe  150  within cylinder  172  towards its base  173 . Advantageously, tip member  176  crosses tail portion  174 , and contains the through hole  175 . 
     Internal syringe  150 , i.e. a portion of cylinder  152  that is not engaged by piston  151 , provides a container  158  for surgical glue  9 , and piston  151  provides a pressurizing means for applying an injection pressure on surgical glue  9 , in order to cause it to flow out of cylinder  152 . External syringe  170 , i.e. a portion of cylinder  172  that is not engaged by syringe  150 , provides a receptacle  178  for barrier liquid  5 , and syringe  150 , which can be manoeuvred as one piece as a piston by means of  157 , provides a liquid outflow means for causing barrier liquid to flow out of cylinder  172 , which can be operated independently from the pressurizing means. Frangible portion  154  keeps the surgical glue and the barrier liquid separated from each other in respective containers, before their use. 
     Double syringe  52  comprises couples of locking teeth  161 / 162 , which operate at the end of a sliding movement of syringe  150  within cylinder  172 , blocking syringe  150  in the final position, in which receptacle  178  of the barrier liquid is substantially empty. Furthermore, a block  163  ( FIGS. 47-49 ) is provided, similar to block  79  of syringe  51 , which prevents piston  151  from being withdrawn with respect to a predetermined starting position, moving away from base  153 . 
     Referring to  FIGS. 46-49 , the operation is now described of a device comprising double syringe  52  and a duct like a needle  41  ( FIGS. 32, 41 and 42 ), a duct  91  that is slidingly coupled with an introducer sheath  3  by means of a short tube ( FIGS. 36 and 37 ), or a catheter  141  for percutaneous endovascular intervention ( FIGS. 43 and 44 ). The device has a dose of surgical glue  9  that is available in container  158 , and an amount of barrier liquid  5 , for example a saline solution, in receptacle  178  ( FIG. 46 ). 
     After hermetically connecting the duct of the device, not shown, with tail portion  174  ( FIG. 46 ), an operator presses on cap  157  to cause internal syringe  150  to slide within cylinder  152  ( FIGS. 46 and 47 ), which reduces the volume of receptacle  178  and causes saline solution to flow from receptacle  178  through hole  175  into the duct that is connected with tail portion  174 . The amount of saline solution is enough to fill a portion of the duct or the whole duct according to specific requirements; receptacle  178  may have a normalized starting capacity, which is enough to fill with barrier liquid ducts that have a length suitable for reaching said remote operation regions through an endovascular path. 
     When receptacle  178  has been substantially emptied, i.e. at the end of an advancing movement of syringe  150  within cylinder  152 , an interference is created between tip member  176  and frangible seal  154  that is broken bringing receptacle  158 , which contains the surgical glue, in communication with the duct. Substantially at the same time of the break of frangible seal  154 , locking teeth  161  that are integral to syringe  150  engage respective locking teeth  162  of cylinder  152  blocking the relative position of internal syringe  150  and of cylinder  152  in the final position. This way, syringe  150  cannot be withdrawn within cylinder  172  with respect to this position, and barrier liquid  5 , which fills the duct, cannot flow either forwards or backwards; furthermore, the block of the starting position of internal piston  151  prevents a saline solution  5 , which has come into contact with surgical glue  9  after break of frangible portion  154 , from flowing back up into container  158  under the blood pressure. 
     Furthermore, the hermetic connection between duct  41 ,  91  or  141  and tail portion  174  prevents any air inlet, therefore barrier liquid  5  is retained within the duct. 
     Therefore, the operator can easily position the duct until outlet mouth  43  or  99  reaches the operation region, where surgical glue  9  must be released, without the blood back pressure that is encountered while moving through the blood vessel (in case of an endovascular intervention) causing internal syringe  150  to move back, blood to flow back up through the duct. Thanks to protection cap  157 , the positioning of the duct in the patient&#39;s body is carried out without any risk of accidentally operating piston  151 , i.e. without any risk of early releasing surgical glue  9 . 
     Once achieved the operation region, the operator removes cap  157  ( FIG. 48 ) and acts on piston  151 , causing surgical glue  9  to flow from container  158  into duct  41 ,  91  or  141 . Then the operator may cause outflow of surgical glue  9  after barrier liquid  5  through the duct, by pushing piston  51  towards base  173  of cylinder  172  ( FIG. 49 ). 
     The foregoing description of specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such embodiments without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.