a. Field of the Invention
The instant invention relates to catheters having an outer surface with multiple aspiration passageways, through which fluids, such as blood, may flow into an interior lumen of the catheter, such as a drainage lumen, an aspiration lumen, or even the central lumen of the catheter. The pattern, design, placement and number of aspiration passageways, or holes, allows for improved catheter performance during procedures, such as transseptal procedures, where the distal tip commonly becomes occluded, while still maintaining the structural integrity and functionality of the catheter.
b. Background Art
Catheters are used in a variety of medical procedures to gain access to interior regions of the body and to perform a variety of procedures, such as the ablation of targeted tissue areas. During such procedures, a physician must carefully and precisely control the position of the catheter. To achieve more precise control of instruments such as ablation catheters, various guiding introducer catheters have been developed.
Typically, in procedures where introducer catheters are used to guide an ablation catheter to a particular location in the heart, a small incision is first made at an appropriate location, for example, the groin, the arm, or any other location known to those skilled in the art, and then an artery or vein is punctured at a relatively shallow angle with an appropriate needle, for example, a stylet or some other puncturing device known to those skilled in the art. The needle is then partially withdrawn from the artery or vein, and reinserted at a steeper angle A guidewire is inserted into the artery or vein and advanced to a desired region, for example to the heart region. An introducer catheter is directed over the guidewire to the desired portion of the heart. An instrument, often embodied in a separate catheter, to be used for the treatment of the heart or the heart region, for example, an ablation catheter, may then be advanced through the lumen of the first catheter and placed at the desired location to perform the desired procedure.
The specific type of introducer catheter used will depend upon what portions of the heart the operation is being performed on, and accordingly whether a transseptal or retrograde procedure is used. In transseptal procedures, for example, a catheter apparatus is introduced into the right femoral vein and advanced through the inferior vena cava into the right atrium. A puncture is then made through the fossa ovalis in the inter-atrial septum and the apparatus is advanced into the left atrium.
One skilled in the art recognizes the many problems inherent in the use of introducer catheters in such procedures. For example, given the intricate anatomy of the heart, it is possible for the distal end of the introducer catheter to become occluded, particularly if the distal tip becomes pressed against tissue, or in extreme cases, blocked with debris, such as plaque or cholesterol. This problem is particularly pervasive when puncturing the fossa ovalis in the aforementioned transseptal procedure. Furthermore, puncturing the fossa ovalis often causes localized bleeding, which can lead to the coagulation of blood and subsequent clogging of any openings at or near the distal end of the introducer catheter.
Because an ablation catheter, when advancing through an interior lumen of the transseptal introducer catheter, is cooled in part by the flow of blood through introducer's interior lumen, an occluded distal end would impede the flow of blood and interfere with the temperature control of the ablation device. Accordingly, it is desirable to place aspiration passageways in the side of the catheters to ensure that blood or other fluids continuously flow through an interior lumen. These aspiration passageways function as relief holes in the side of the introducer catheter which allow for the flow of blood into an interior lumen and through the catheter when the distal end of the catheter is occluded. Therefore, it is one object of the present invention to provide improved catheters for a variety of transseptal and retrograde procedures, where the design of aspiration passageways prevents the occlusion of the catheter.