Innovative device for vascular access in dialysis treatment

Abstract

A device (100) for performing arteriovenous fistula-type vascular access during dialysis treatment includes a first vertical branch (1) of an artery and a second vertical branch (2) of a vein, both branches being hollow and arranged parallel to each other, with their lumens connected via a horizontal branch (7). The device (100) includes at least two blood flow interception devices (10, 11), wherein the first interception device (10) is disposed on the horizontal branch (7), and the second interception device (11) is disposed in the distal portion (2') of the vein of the second vertical branch (2).

Description

Technical Field

[0001] This invention relates to an innovative device for vascular access during dialysis treatment. In particular, the present invention aims to minimize common practice-related hemodynamic complications associated with dialysis treatment, namely hemodynamic complications related to difficulties in establishing and maintaining vascular access. Background Technology

[0002] Chronic Kidney Disease (CKD) is defined as a clinical condition lasting at least three months, characterized by impaired kidney function and / or kidney damage. According to international guidelines published by Kidney Disease Improving Global Outcomes (KDIGO), CKD is classified into six progressively more severe stages based on the degree of reduction in glomerular filtration rate and the presence of albuminuria / proteinuria. Staging takes into account varying degrees of mortality risk and the progression of CKD toward renal replacement therapy (dialysis or transplantation). The causes of CKD are generally classified into glomerular, tubular, and interstitial nephropathy. These are numerous but often remain unrecognized until irreversible damage to kidney function occurs. In fact, once established, CKD, regardless of its cause, in most cases progresses more or less slowly to the final stage of uremia, a life-threatening clinical condition requiring long-term treatment to replace kidney function (dialysis or transplantation).

[0003] The functional unit of the kidney is the nephron, a small cluster of blood vessels through which excess water and metabolic waste products from the blood pass, leading to the formation of urine. Each kidney contains approximately one million nephrons and can maintain homeostasis until kidney damage exceeds 80%, the threshold for the appearance of clinical and laboratory signs of kidney failure. When the glomerular filtration rate (GFR) falls below 15 ml / min, this leads to end-stage renal disease (ESRD), characterized by the destruction of more than 95% of the nephrons, in which the kidney is no longer able to maintain the balance of fluid volume and composition, resulting in the dangerous accumulation of water and catabolite products (toxins) in the blood.

[0004] ESRD is a life-threatening condition that requires treatment to replace kidney function, which can be natural (kidney transplant) or artificial (hemodialysis or peritoneal dialysis). Peritoneal dialysis and kidney transplantation are not considered as they are beyond the scope of this discussion.

[0005] Hemodialysis is a complex treatment procedure based on the physical principle of diffusion, which purifies the blood of patients with uremia. The method uses a device with a peristaltic pump that delivers blood carrying toxic metabolites through a sterile extracorporeal circuit.

[0006] The nerve center of the entire system is the filter, or dialyzer, a cylindrical chamber a few centimeters in diameter containing thousands of microtubes, each with a diameter on the order of micrometers. These tubes are then immersed in a liquid (dialysis bath) pumped from the device into the filter in the opposite direction to the blood flow. Within the dialyzer, contact between the blood and the dialysate occurs through a semipermeable membrane that forms the walls of the microtubes. Passage through this semipermeable membrane is highly selective, allowing only certain molecules to pass through, based on their chemical and physical properties and according to the principle of diffusion: in this system, toxins pass from the environment with the highest concentration (blood) to the environment with the lowest concentration (dialysis fluid), while substances beneficial to the body follow the opposite pathway.

[0007] A peristaltic pump draws in the patient's toxin-laden blood and returns purified, more beneficial blood at an average flow rate of 300 ml / min. Since a standard dialysis session lasts 4 hours, the total amount of blood passing through the filter per treatment is approximately 72 liters. Considering that an adult's blood volume is approximately 5 liters, this is processed approximately 15 times during a dialysis procedure as described above. Therefore, the two needles placed in the patient's arm at each dialysis stage (one for drawing blood and the other for returning it) must be inserted into vessels of a size sufficient to ensure this high flow rate. For this reason, each patient in a long-term hemodialysis program must have adequate vascular access to ensure the high blood flow required for artificial purification. There are three types of vascular access used for hemodialysis: arteriovenous fistula (AVF), central venous catheter, and vascular prostheses. International guidelines published by scientific societies agree that AVF is the preferred vascular access because it is associated with increased survival, significantly improved quality of life, longer duration of treatment, and a lower risk of complications.

[0008] From a technical standpoint, the setup of an AVF (arteriovenous fistula) for hemodialysis involves surgically connecting a vein and artery in the forearm to directly bypass high-pressure blood from the artery into the vein; to prevent some of the blood introduced into the vein from flowing back into the hand, the vein downstream of the anastomosis is usually ligated. This type of surgery is typically performed by anastomosing the radial artery to the cephalic vein of the forearm at wrist level, technically known as a distal lateral radial arteriovenous fistula. Postoperatively, the AVF matures within 3–4 weeks: the high pressure from the arterial column of blood causes an increase in diameter and thickening of the vein wall, a process called “venous arterialization,” resulting in a significant increase in blood flow within the vein, sufficient to maintain the high flow rates required for dialysis treatment.

[0009] However, AVFs are known to carry different types of complications: intravascular, extravascular, and hemodynamic. Specifically, extravascular complications include aneurysms, pseudoaneurysms, and seromas, while hemodynamic complications are represented by "steal syndrome" and high-flow cardiac decompensation. Specifically, an aneurysm is an expansion of the "arterialized" portion of a vein, with a diameter twice that of the unexpanded portion; a pseudoaneurysm is a perivascular blood collection without its own wall, caused by a rupture of the vessel wall, maintaining communication with the vessel via a loop containing high-velocity blood flow (the greatest risk for aneurysms and pseudoaneurysms is given by the likelihood of rupture); a hematoma is an unsupplied perivascular blood collection. The risk of this type of complication is associated with the likelihood of external compression of the AB, leading to pathway obstruction; lipomas are serous fluid collections more common in patients with vascular prostheses. The risk of seroma is primarily infectious; "steal syndrome" is a clinical manifestation of an ischemic type that affects the distal part of the limb as a site of AVFs: in the most severe cases, it is characterized by gangrenous lesions of the fingers, which usually require destruction of the necrotic limb (it most commonly affects patients with proximal AVFs, but is also increasing in patients with distal AVFs due to the increasing number of elderly hemodialysis patients, diabetic patients, and patients with peripheral vascular disease).

[0010] Publications by Basile C et al. showed that adding traditional risk factors to the typical non-traditional risk factors in patients with CKD resulted in left ventricular hypertrophy in 60% of uremia patients even before initiating dialysis. Publications by Stern et al. showed that the causes of high-flow AVF include the presence of congenital or acquired AVF. Many other scientific studies have long demonstrated a close relationship between hemodialysis AVF and heart failure: Basile et al. showed that uremia patients with high-flow AVF have a higher risk of developing heart failure, and that cardiac changes can significantly regress after vascular access closure.

[0011] Therefore, there is a need for an innovative device for AVF-type vascular access in dialysis treatment that can overcome the above-mentioned disadvantages, thereby greatly simplifying the surgical procedure for setting up the AVF and reducing extravascular complications associated with the use of the AVF. Summary of the Invention

[0012] The purpose of this invention is to minimize hemodynamic complications associated with the use of AVF in patients undergoing dialysis by using this invention.

[0013] The innovative device was surgically implanted into a patient's forearm by transversely cutting the four stumps of two blood vessels on a vertical branch and then performing a full-channel anastomosis.

[0014] The device is equipped with at least two septa that are activated (opened or reduced) before the start of the dialysis phase to ensure the high flow required for sufficient blood purification and to maintain a minimum blood flow at the end of treatment, which varies from patient to patient but is to avoid thrombosis of the AVF and restore physiological circulation to the upper limb.

[0015] Advantageously, the additional diaphragm of the device under discussion is capable of delivering the entire arterial flow into the “arterialized” vein, thereby further increasing the blood flow available for purification.

[0016] Therefore, according to the independent product claims, the present invention defines an innovative device for establishing AVF-type vascular access during dialysis treatment. Further preferred and / or particularly advantageous modes of realizing the invention are described according to the features set forth in the appended dependent claims. Attached Figure Description

[0017] The invention will now be described with reference to the accompanying drawings, which illustrate some non-limiting implementation examples, in which:

[0018] Figure 1 A schematic diagram of an apparatus for performing dialysis according to the present invention is shown;

[0019] Figure 2 A schematic diagram of an apparatus for performing dialysis according to another embodiment of the present invention is shown. Detailed Implementation

[0020] This invention relates to an innovative device 100 for vascular access in dialysis treatment. For example... Figure 1 As shown, device 100 has an "H"-like shape and includes a first vertical branch 1 (artery) and a second vertical branch 2 (vein). Both branches are hollow and arranged parallel to each other, with their lumens connected via a horizontal branch 7. Vertical branches 1 and 2 each include distal portions 1' and 2' and proximal portions 1" and 2", respectively. Device 100 is entirely constructed of biocompatible material. It is implanted into the patient's forearm through full-channel anastomosis of four stumps on vertical branches 1 and 2: two stumps of arteries 3 and 4 and two stumps of veins 5 and 6 after transverse incision of the two vessels. Specifically, distal portion 1' of device 100 is connected to distal arterial stump 4, proximal portion 1" is connected to proximal arterial stump 3, and distal portion 2' of device 100 is connected to distal venous stump 6, and proximal portion 2" is connected to proximal venous stump 5.

[0021] The device 100 also includes at least two blood flow interception devices or diaphragms: a first diaphragm 10 is disposed near the middle of the horizontal branch 7, and a second diaphragm 11 is disposed in the distal portion 2' of the venous branch 2.

[0022] Preferably, the device is equipped with a battery-powered power supply (for a pacemaker) and a suitable actuation device, so that the permeability of diaphragms 10 and 11 can be adjusted from the outside via remote control.

[0023] The diaphragms 10 and 11 of the horizontal branch 7 and the vertical venous branch 2 are operated before the start of the dialysis phase, opening diaphragm 10 and closing diaphragm 11 to ensure the high flow required for sufficient blood purification. In other words, this operation allows blood flow within the vein to be maximized during dialysis and returned to normal at the end of the dialysis treatment. This significantly reduces the risk of complications from dialysis treatment while keeping the vascular access open for subsequent dialysis sessions. At the end of treatment, diaphragm 10 is reduced to maintain a minimum blood flow, which varies from patient to patient, to prevent thrombosis of the AVF, while diaphragm 11 of venous branch 2 is opened to restore physiological circulation to the upper limb. According to another embodiment of the invention, device 100 includes a third diaphragm 12 disposed in the distal portion 1' of arterial branch 1. Its closure during the dialysis phase can be used to divert the entire arterial flow into the “arterialized” vein to further increase the flow rate of blood available for purification. Thus, this additional third diaphragm 12 is used in some patients where the arteriovenous fistula is also supplied by the ulnar artery, which typically supplies the hand. The third diaphragm 12 closes during dialysis to prevent the loss of blood supplied to the hand via the ulnar artery. At the end of treatment, the third diaphragm is opened to restore physiological circulation to the upper limb.

[0024] The blood flow blocker or diaphragm must also be made of highly biocompatible materials, similar to those used in heart valve prostheses, in order to minimize the possibility of thrombosis.

[0025] Preferably, device 100 provides significant simplification for AVF surgery. AVF surgery is a vascular microsurgery procedure requiring considerable experience and dedication, and therefore the number of nephrologists performing this type of interventional procedure is currently decreasing. Furthermore, the outcome of the procedure is subject to significant individual variability, depending not only on the patient's characteristics but also on the nephrologist's skill and experience.

[0026] Therefore, the operation of selecting the cross-section of the blood vessel for AVF and the implantation of the device object of the present invention, as well as the full-channel anastomosis of the four vascular stumps, represent a simplified surgical procedure that can be easily performed by a nephrologist or vascular surgeon after a short training period, thereby standardizing surgical techniques and outcomes and making them more independent of the operator's level of experience.

[0027] Preferably, device 100 allows for a significant increase in flow rate and purification index. The possibility of achieving very high blood flow rates within the limited duration of dialysis makes it possible to achieve optimal purification levels associated with increased survival rates and improved quality of life.

[0028] Preferably, device 100 also allows the “fistula-first” procedure to be extended to patients with heart disease and those with chronic obstructive pulmonary disease. Because the device allows for high flow rates for short periods (12 hours / week or 7.1% of total time) and restoration of physiological circulation for the remaining time (156 hours / week or 93.1% of total time), it can also be extended to uremia patients with COPD and heart disease who are currently excluded from AVF packaging procedures by their clinical condition and are undergoing dialysis via CVC placement (“second-choice” vascular access) or peritoneal dialysis.

[0029] Preferably, device 100 achieves a significant reduction in extravascular complications (aneurysms, pseudoaneurysms, hematomas) associated with AVF use. Extravascular complications of AVF are very common and are often related to unexpected factors associated with the procedures of cannulation and hemostasis after hemodialysis. The use of this device does not directly reduce the likelihood of such complications, but by significantly reducing flow in arterialized veins after hemodialysis, it determines substantial changes in their evolution, which in most cases resolve spontaneously: hematoma containment and size reduction, aneurysm growth slowing, and pseudoaneurysms more easily closure spontaneously around their necks. All of this translates into a net reduction in hospitalizations due to vascular access complications.

[0030] Preferably, device 100 achieves a reduction in hemodynamic complications associated with AVF use: "steal syndrome" and high-flow heart failure. The use of device 100, limited by the duration of dialysis sessions and the subsequent immediate restoration of physiological circulation in the forearm, leads to a dramatic reduction in "steal syndrome" and high-flow cardiac decompensation, resulting in a net decrease in mortality and improved quality of life for uremia patients undergoing long-term hemodialysis. All of this translates into a net reduction in hospitalizations due to vascular access complications.

[0031] Preferably, device 100 allows for the maintenance of vascular access in kidney transplant patients. The ability of this device to significantly reduce high venous return to the heart allows for the maintenance of vascular access even after kidney transplantation. For this reason, nephrologists can agree with the patient and list the potential disadvantages and advantages of maintaining vascular access, with the risk of developing hemodynamic complications over time, or closing the AVF, relinquishing a portion of the patient's venous heritage, which would require the patient to undergo the construction of another vascular access in the event of mandatory resumption of hemodialysis. Restoring physiological forearm circulation using this device alleviates this difficult choice for both nephrologists and patients, thus preserving a ready-to-use, "non-destructive" vascular access in the event of resumption of dialysis.

[0032] In addition to the methods for implementing the invention as described above, it should be understood that many other variations exist. It should also be understood that the above embodiments are merely illustrative and do not limit the subject matter of the invention, nor its possible applications or configurations. Rather, although the foregoing description enables those skilled in the art to implement the invention at least according to exemplary configurations, it should be understood that many variations of the described components are conceivable without departing from the purpose of the invention as defined, literally interpreted, and / or according to its legal equivalents in the appended claims.

Claims

1. A device (100) for performing arteriovenous fistula-type vascular access during dialysis treatment, comprising a first vertical branch (1) of an artery and a second vertical branch (2) of a vein, both branches being hollow and arranged parallel to each other, with their lumens connected via a horizontal branch (7); characterized in that, It includes at least two blood flow interception diaphragms (10, 11), wherein the first interception diaphragm (10) is disposed on the horizontal branch (7), and the second interception diaphragm (11) is disposed in the distal portion (2') of the vein of the second vertical branch (2); The first intercepting dialysis membrane (10) and the second intercepting dialysis membrane (11) are configured to operate before the start of the dialysis phase, opening the first intercepting dialysis membrane (10) and closing the second intercepting dialysis membrane (11) to ensure the high flow rate required for blood purification.

2. The apparatus (100) according to claim 1, characterized in that, The device (100) also includes a third diaphragm (12) disposed in the distal portion (1') of the first vertical branch (1) artery.

3. The apparatus (100) according to claim 1 or 2, characterized in that, The distal portion (1') of the first vertical branch (1) artery is connected to the distal arterial stump (4), and the proximal portion (1") of the first vertical branch (1) artery is connected to the proximal arterial stump (3), while the distal portion (2') of the second vertical branch (2) vein is connected to the distal venous stump (6), and the proximal portion (2") of the second vertical branch (2) vein is connected to the proximal venous stump (5).

4. The apparatus (100) according to claim 1, characterized in that, The device is made entirely of biocompatible materials.

5. The apparatus (100) according to claim 1, characterized in that, The device (100) includes a power supply device and an actuator device configured to adjust a first intercepting diaphragm (10) and a second intercepting diaphragm (11).

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