Abstract:
The system for removing blood containing contrast dye includes an inner catheter having a fixed proximal end and a distal free end, and an outer catheter coaxially disposed around a portion of the inner catheter, defining an inner lumen and an annular outer lumen. The fixed end of the inner catheter is coincident with the proximal end of the outer catheter, and the distal end of the inner catheter extends outward from the outer catheter. A valve manifold provides a single operator control over the operation of the catheters and balloon in order to drain the dye from the coronary sinus system.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/801,690, filed Mar. 15, 2013. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the prevention of contrast-associated nephropathy, and particularly to a catheter and valve system and method for removing blood containing contrast dye. 
     2. Description of the Related Art 
     Percutaneous transluminal coronary angioplasty is frequently used in treating coronary atherosclerosis, which produces areas of blockage within a coronary artery. However, prior to performing percutaneous transluminal coronary angioplasty, and during the procedure itself, iodine containing dye or other contrast material is injected into a patient&#39;s coronary arteries through a catheter. This iodine solution is fluorescent and enables the coronary arteries to be clearly illustrated for the physician. 
     A serious problem associated with the use of such contrast solutions exists. The use of such solutions may lead to contrast-induced nephropathy. Contrast-induced nephropathy can result in transient or permanent renal impairment or failure of a patient&#39;s kidneys. It is well known that renal dysfunction is associated with the use of radiographic contrast media, and that the dysfunction may range from a transient slight increase in serum creatinine levels to renal failure requiring transient or long-term dialysis. 
     Many patients require revascularization of more than a single vessel. However, when there is danger of contrast-induced renal failure, the vessels are operated on in separate procedures at greatly increased cost and additional risk of arterial puncture. Therefore, it is highly desirable or imperative to eliminate the risk of renal failure. 
     Further, there are many other patients with chronic renal insufficiencies who must wait 24 to 48 hours in the hospital before undergoing percutaneous transluminal coronary angioplasty in order to space the kidney load associated with the contrast load. Still others, particularly the elderly with a pre-existing renal insufficiency, make up a large group in which angioplasty is avoided due to multi-vessel disease and multi-vessel intervention, which may lead to renal failure. 
     Contrast-induced nephropathy can be prevented if the contrast solution is kept away from the kidney. However, once the dye has been mixed with blood, the conventional method to separate the two is by filtration (for example, through dialysis). Dialysis relies on diffusion down a concentration gradient and is not completely effective if the concentration of dye in the blood to be filtered is low. Furthermore, the flow rates of conventional hemodialysis procedures are too high for patients who are undergoing angioplasty, and these patients typically do not tolerate wide fluctuations in blood pressure, as is common with hemodialysis. 
     Thus, A system and method for removing blood containing contrast dye solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The system and method for removing blood containing contrast dye, such as radiographic contrast media used for angioplasty procedures, relates to the removal of blood containing contrast dye solution from the coronary sinus of the patient&#39;s heart before the blood containing the dye enters the right atrium and circulates through the bloodstream to the kidneys, potentially causing contrast-induced nephropathy (CIN). The system for removing blood containing contrast dye includes an inner catheter having opposed fixed and free ends, and an outer catheter. The inner catheter is partially disposed coaxially within the outer catheter, defining inner and outer lumens. The fixed proximal end of the inner catheter is positioned within the outer catheter, and the distal end of the inner catheter partially extends outward from the outer catheter. An annular suction orifice is defined between the outer catheter and the inner catheter at the distal end of the outer catheter. A guide may be further provided for covering the annular suction orifice and holding the inner catheter in place with respect to the outer catheter. The guide has openings or apertures formed therethrough, allowing blood containing the contrast dye to be suctioned therethrough. 
     A balloon is mounted on the outer catheter adjacent the annular suction orifice. The distal free end of the inner catheter extends beyond the balloon. An inflation line is in communication with the balloon. The inflation line terminates in a first inflation port. In use, the catheters, which have a curvature that facilitates the insertion of the system in the coronary sinus, are inserted into the coronary sinus, the outer catheter extending to the ostium and the inner catheter extending into the sinus. The balloon is inflated after introducing a contrast solution into a patient&#39;s blood stream. Blood containing contrast solution from between the first and second balloons is then removed. The second balloon is inflated first in order to anchor the inner catheter in place in the coronary sinus, the free end thereof being positioned adjacent the patient&#39;s lateral vein. Preferably, the inner catheter is formed from a softer material than the outer catheter, thus allowing the outer catheter to be used for positioning, and preventing damage to the inner wall of the coronary sinus vein. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an environmental partial perspective view diagrammatically illustrating a system for removing blood containing contrast dye according to the present invention. 
         FIG. 2  is a perspective view of a balloon catheter of the system of  FIG. 1 , shown with the balloon deflated. 
         FIG. 3  is a perspective view of the balloon catheter of  FIG. 2 , shown with the balloon inflated. 
         FIG. 4  is a perspective view of a valve assembly of the system for removing blood containing contrast dye of  FIG. 1 . 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The system and method for removing blood containing contrast dye maximizes the filtration of contrast solution from the blood by placing a catheter in the coronary sinus where the concentration of contrast dye is the highest. The catheter is provided with means for blocking the flow of blood to the right atrium, while simultaneously permitting the blood in the coronary sinus to be delivered through the catheter to a filtration machine. The way in which this is accomplished is explained with reference to  FIG. 1 , which illustrates a heart in which a catheter  10  has been introduced from the groin, then through the inferior vena cava (IVC) into the coronary sinus (CS). The distal portion of the catheter  10  carries a balloon  12 , which can be inflated and deflated as required. Balloon catheters are well known and, therefore, the actual catheter construction is not described in detail. In addition to balloon  12 , catheter  10  also includes a port, defined by a porting inner catheter  14 , distal but close to the balloon  12 , which permits blood in the coronary sinus to drain into the catheter lumen when the balloon  12  occludes the coronary sinus. 
       FIGS. 2 and 3  show structure of the catheter  10  in a perspective view. The catheter  10  is preferably positioned with its tapered distal end distal of the coronary sinus and balloon  12 , which is expanded to block blood flow from the coronary sinus to the right atrium. The catheter  10  has an outer diameter on the order of 8 Fr (French). Internal to the catheter  10 , an inner guide catheter  14  is shown at the distal end of catheter  10 , the inner guide catheter having a diameter on the order of 4 Fr. In other words, the catheter  10  is a double lumen catheter in which the lumens are coaxial, the inner guide catheter  14  defining an inner lumen and the annular space between the inner guide catheter  14  and the outer catheter defining an annular outer lumen. The inner guide catheter  14  provides the porting for the contrast dye being used in the patient evaluations. The balloon  12  is shown deflated in  FIG. 2 , at which state the catheter will be introduced or retracted from the patient.  FIG. 3  shows the balloon  12  inflated, which is the state at allowing for the occlusion of the coronary sinus. The function of the single balloon catheter is well known, and is used in conjunction with the valve system of  FIG. 4 . 
       FIG. 4  shows a valve assembly structure intended for operation by a single user, for use with the catheters  10  and  14  of  FIGS. 1-3 . The valve assembly has a manifold  20  and a piston drive (or plunger)  30  slidable in the manifold  20  for producing the necessary positive and negative pressures to the catheters  10 ,  14 . The piston drive (or plunger)  30  is a manually operated pressure inducer for inflating and deflating the balloon  12 . Within the manifold  20 , a conduit  22  is connected to various ports, as will be described in detail below. Within the conduit  22 , a sliding dual headed plunger  24  provides seals between the various ports for fluid engagement with the catheters  10 ,  14  and the balloon  12 . The manifold  20  has a first port  32  for introducing and removing the fluid (e.g., air or saline) to the balloon  12 . Associated with the first port  32  is a second port  34 , serving as a pressure relief port for maintaining a safe pressure of the balloon  12  within the blood vessels of the patient. 
     Third and fourth ports  38  and  40 , respectively, are provided for aspiration of the catheters  10 ,  14 . Ports  38 ,  40  extract the contrast dye from the catheters  10 ,  14 . The third and fourth ports  38 ,  40  function along with dual headed plunger  24  within the manifold conduit  22 . A fifth port  46  provides a vacuum connection. The vacuum is provided via a collection syringe  66 , or a negative pressure source to aid in the aspiration of the dye to be collected. The manifold  20  provides a single operator the ability to control inflation and deflation of the balloon  12 , as well as to aspirate contrast dye from the blood vessels. 
     The manifold  20  also includes a locking mechanism  28  for sustaining the piston drive (or plunger)  30  in a selected position for affording the operator the ability to facilitate the various functions during the dye drainage procedures. The spring-biased dual-headed plunger  24  is designed and configured to maintain a fluid seal across the aspirators. Attached to the first, third, and fourth ports  32 ,  38 ,  40  are respective three-way stop cocks  50 ,  52 ,  54 . Each stop cock provides a specific function when used in conjunction with the manifold  20 . 
     In use, the first port  32 , along with its three-way stop cock  50 , are attached to the balloon inflation line. A vacuum syringe  66  is attached to the fifth vacuum port  46 . The plunger  30  is moved so that all air is removed from the balloon  20  inflation line and the syringe  66 . Once this preparation has been accomplished, the vacuum syringe  66  is used to apply maximum negative pressure to the internal conduit  22 , and the syringe  66  is then locked in place. All three stop cocks  50 ,  52 ,  54  are secured in their respective first position. Contrast dye is then injected into the coronary arteries, and the balloon  12  is inflated by depressing the piston drive (or plunger)  30  of the manifold  20 . Any excess pressure in the balloon inflation line will be expelled via the pressure relief port  34 . 
     By depressing the piston drive (or plunger)  30 , the dual headed plunger  24  is forced along the internal conduit  22  of the manifold  20 , becoming aligned with the third and fourth aspiration ports  38 ,  40  and compressing the spring  42 . In this position, a vacuum is automatically activated through the outer and inner catheters  10 ,  14 . The syringe  66  will collect the dye that has been aspirated via the catheters  10 ,  14 , and the piston drive (or plunger)  30  is moved in an opposite direction. Once retracted, the piston drive (or plunger)  30  relieves the pressure in the manifold  20  and deflates the balloon  12 . Simultaneously, the dual-headed plunger  24  is spring-biased within the conduit  22  and seals the aspirator ports  38 ,  40 . The syringe  66 , now filled with the dye drained from the sinus system, may be removed, emptied, and returned to continue the dye draining process. 
     During operation, when the contrast dye is not being removed, the three-way stop cocks  52 ,  54  on the third and fourth ports  38 ,  40  are positioned to allow a slight blood drip, thereby preventing clotting within the dye drain system lumens. It should be understood that the contrast dye drain system provides a manifold  20  that allows a single operator to inflate the balloon  12  and simultaneously drain the dye from the coronary sinus system without having to monitor a separate pressure measuring system for the applied pressure. The manifold  20  provides a structure that affords easy connections for the ports. The manifold  20  is easily reset for multiple withdrawals within one single procedure. The manifold  20  is also fabricated of materials that make it cost effective for ready disposal. Likewise, manifold  20  may be manufactured from materials that provide for the reuse of the system after appropriate cleaning and sterilization. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.