Abstract:
The present invention describes a long-term central venous catheter (CVC) for use in haemodialysis treatments with two cuffs in the end section to be positioned in the subcutaneous tunnel.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the field of medical and surgical devices and in particular to a long-term or tunnelled Central Venous Catheter (CVC) which can remain in place for long periods of time (months or years). 
       PRIOR ART 
       [0002]    The Central Venous Catheter (CVC) is a device which is placed into a large vein in order to carry out haemodialysis treatment. It is used when it is not possible to perform a vascular access using the patient&#39;s own vessels or prosthetic vessels. It is usually made up of a double-lumen cannula, one used for suction and the other enabling re-entry of blood which has been treated and purified using a dialyser. 
         [0003]    In some cases we see single-lumen cannulas, and in these cases two separate cannulas must be used. The CVC can be manufactured in various polymers: polyurethane, silicone or copolymers such as carbothane. CVCs can be temporary, which remain in place for short periods (2-3 weeks) and have immediate percutaneous access through the skin directly to the central vein, or they can be long-term or tunnelled, which can remain in place for much longer periods (months or years) and provide a passage under the skin (subcutaneous tunnel). 
         [0004]      FIG. 1  reports data concerning the vascular access in use in various DOPPS countries (DOPPS 4 data, 2010). The long-term central venous catheter continues to hold a high percentage (10-30% depending on the country) among patients undergoing chronic haemodialysis, despite guideline recommendations to reduce the use of such a device. So far, prevalence trends over the past few years show a continual increase compared with past periods. In Italy, the prevalence of long-term CVCs in patients undergoing haemodialysis was 15% in 2007 (DOPPS 3) and 23.8% in 2010 (DOPPS 4). 
         [0005]    The most significant and serious catheter-related complications are infections. Infections related to long-term CVCs are expressed as the following clinical conditions:
       Bacteriaemia or sepsis   Infection of the exit site and the subcutaneous tunnel       
 
         [0008]    If we compare the various types of vascular access, the relative risk (RR) of access-related bacteraemia with respect to arteriovenous fistula using native veins is 15.5 for patients with a tunnelled CVC and 25.5 for patients with a temporary CVC. 
         [0009]    The incidence of infections from long-term (or tunnelled) CVCs is 1.6-5.5 cases/1000 catheter days, and 3.8-6.6 cases/1000 catheter days for temporary catheters. 
         [0010]    All tunnelled CVCs which have been marketed and used in clinical practice up until now are featured by a single cuff, usually made from Dacron® and positioned in the end section of the CVC (corresponding to the subcutaneous passage). A few days following positioning, a scarring reaction occurs which anchors the CVC to the subcutaneous tissue and closes the opening preventing micro-organisms from the external environment from entering the bloodstream. You can, however, create these scenarios:
       if the cuff is positioned close to the exit site it provides an excellent barrier against micro-organisms with a low incidence of bacteremia and infections of the subcutaneous tunnel, but a weak anchoring of the CVC with risk of leakage;   if the cuff is positioned deeper in relation to the subcutaneous tunnel, it provides an excellent anchoring system but a greater stretch of tunnel is exposed to micro-organisms, therefore resulting in a greater risk of infection of the tunnel.       
 
         [0013]    The purpose of this invention is to provide a tunnelled CVC with an improved anchoring system and antibacterial barrier to reduce the incidence of:
       1) CVC-related infections   2) subcutaneous tunnel infections   3) displacement of the CVC.       
 
       SUMMARY OF THE INVENTION 
       [0017]    The present invention solves the above mentioned problems by way of a non-temporary CVC ( 50 ) for use in haemodialysis treatments characterised in that, in the end section to be positioned in the subcutaneous tunnel, it comprises two cuffs ( 51 ) and ( 52 ) spaced apart by a distance in the range between 3 and 8 cm so that cuff ( 51 ) is positioned within the subcutaneous tunnel in the proximity of the exit site ( 57 ) and cuff ( 52 ) is positioned within the subcutaneous tunnel in the proximity of the access point ( 58 ) to the catheterised central vein. 
         [0018]    Due to the two cuffs, the CVC according to the invention can be implanted for long periods of time equal to months or years and so can be classified among the so-called long-term or tunnelled CVCs. 
         [0019]    Cuff ( 51 ), preferably positioned 1-2 cm from the exit site ( 57 ), provides an excellent antibacterial barrier whilst cuff ( 52 ), preferably positioned 1-2 cm from the point of access ( 58 ) to the central vein into which the catheter is inserted, provides excellent anchoring of the CVC to the subcutaneous tissue. 
         [0020]    Surprisingly, in preliminary data concerning the use of the new CVC with the double-cuff “Bandera modification” on a sample of 11 patients for a total observation period of 3310 catheter days, only two tunnel infections were observed (corresponding to an incidence of infection equal to 0.6 cases/1000 catheter days) and no displacements. 
         [0021]    Therefore, the preliminary results are significant, despite referring to a short observation period and a low number of patients, they show a clear and significant reduction in the incidence of infectious episodes related to the CVC compared to what is reported in the literature (0.6 cases/1000 catheter days vs. 1.6-5.5 cases/1000 catheter days). Such a reduction in the incidence of infections associated with no displacement is an absolutely unexpected result. 
         [0022]    The positioning of the CVC has not resulted in any additional difficulty, neither has its removal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  shows data concerning the vascular access in use in various DOPPS countries (DOPPS 4 data, 2010); 
           [0024]      FIG. 2(A)  shows a bilumen CVC according to the invention equipped with two cuffs ( 51 ) and ( 52 ); (B) shows a cross-section of the CVC according to the invention. 
           [0025]      FIG. 3  shows a CVC according to the invention as inserted into a patient who must undergo frequent haemodialysis treatments. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    The cuffs ( 51 ) and ( 52 ) are preferably made of a polyethylene terephthalate fibre (for example DACRON®) or other biocompatible material that causes a fibrotic reaction with the subcutaneous tissue. 
         [0027]    The term cuff refers to a sleeve (cylindrical tube coaxial to the catheter) applied in a non-sliding manner to the outer surface of the catheter. 
         [0028]    The two cuffs ( 51 ) and ( 52 ) have, independently of each other, a length in the range between 5-10 mm and thickness in the range between 0.5 and 2.0 mm. Preferably, the cuffs have a length of 8 mm and thickness of 1.0 mm. Preferably, the two cuffs ( 51 ) and ( 52 ) are identical in size and shape. 
         [0029]    Preferably, cuff ( 52 ) is spaced apart from the tip ( 53 ) of the CVC by a distance (x) in the range between 18 and 26 cm. In particular for the right side CVC the distance (x) is preferably in the range between 19 and 20 cm; for the left side CVC the distance (x) is preferably in the range between 23 and 25 cm. 
         [0030]    The “double cuff system” can be applied to all types of CVC, both double- and single-lumen. 
         [0031]    The material comprising the CVC can be silicone or another material usually used for such medical devices. 
         [0032]    Therefore, for example, the CVC according to the invention has, like other known and commercially available CVCs:
       length in the range between 150 and 450 mm,   external diameter, preferably oval or circular, of between 3.0 and 6.5 mm,   internal diameter, preferably circular, of between 1.5 and 3.0 mm.       
 
         [0036]    Like other known CVCs, the CVC ( 50 ) according to the invention, with reference to  FIG. 2A , can preferably be equipped, in a kit, with suture wings ( 54 ), one or more clamps ( 55 ), one or more luer-lock connectors ( 56 ), one or more luer-lock plugs. Below is a table of the preliminary clinical data relating to the positioning of CVCs according to the invention: 
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
               
               
                 PATIENT 
                 DATE CVC 
                   
                 DATE OF 
                 DATE OF 
                 Catheter 
               
               
                 NO. 
                 INSERTED 
                 TYPE OF CVC 
                 INFECTION 
                 REMOVAL 
                 days 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 18 Feb. 2010 
                 BILUMEN 
                 No infection 
                 2 Sep. 2010 
                 196 
               
               
                   
                   
                   
                   
                 malfunctioning 
               
               
                 2 
                 28 Jul. 2009 
                 BILUMEN 
                   
                 5 Jan. 2011 
                 526 
               
               
                   
                   
                   
                   
                 deceased CVC 
               
               
                   
                   
                   
                   
                 functioning 
               
               
                 3 
                 22 Jul. 2009 
                 BILUMEN 
                   
                 Deceased 
                 506 
               
               
                   
                   
                   
                   
                 12 Nov. 2010 
               
               
                 4 
                 8 Apr. 2010 
                   
                   
                 Deceased 
               
               
                   
                   
                   
                   
                 15 Apr. 2010 
               
               
                 5 
                 12 Mar. 2010 
                 SINGLE- 
                 1 Jun. 2010 
                 22 Jul. 2010 
                 130 
               
               
                   
                   
                 CANNULA 
                 tunnel infection 
               
               
                 6 
                 20 Nov. 2009 
                 BILUMEN 
                   
                 19 Jul. 2011 
                 590 
               
               
                   
                   
                   
                   
                 due to death 
               
               
                 7 
                 29 Jun. 2010 
                 BILUMEN 
                   
                 1 Sep. 2010 
                 60 
               
               
                   
                   
                   
                   
                 due to death 
               
               
                 8 
                 6 Jul. 2010 
                 TWO SINGLE- 
                   
                 Fully 
                 590 
               
               
                   
                   
                 CANNULA 
                   
                 functioning 
               
               
                 9 
                 13 Jul. 2010 
                 TWO SINGLE- 
                 21 Sep. 2010 
                 13 Jan. 2011 
                 184 
               
               
                   
                   
                 CANNULA 
                 subcutaneous 
                 due to AVF 
               
               
                   
                   
                   
                 tunnel infection 
                 puncture 
               
               
                 10 
                 10 Aug. 2010 
                 Two single- 
                 No infection 
                 11 Nov. 2010 
                 92 
               
               
                   
                   
                 cannula 
                   
                 Showing 
               
               
                   
                   
                   
                   
                 above the skin 
               
               
                 11 
                 19 Aug. 2010 
                 TWO SINGLE- 
                 No infection 
                 8 Nov. 2011 
                 440 
               
               
                   
                   
                 CANNULA 
                   
                 Due to 
               
               
                   
                   
                   
                   
                 subcutaneous 
               
               
                   
                   
                   
                   
                 passage fissure 
               
               
                   
               
             
          
         
       
     
         [0037]    Results of the Preliminary Study:
       2 infectious episodes out of a total of 3310 catheter days=0.6 infectious episodes/1000 CVC days   no displacements