Device for retrieval of defect closure devices

A device for retrieval of defect closure devices, comprising a closure-catch catheter having at a distal end thereof a closure-catching device and at a proximal end thereof, a grip for operating the closure-catching. An elongated sheath having a lumen and is provided at the proximal end thereof with a lateral injection tube and hemostatic device. The catheter is moveably insertable in the lumen.

BACKGROUND OF THE INVENTION 
The present invention relates to a device for retrieval of defect closure 
devices and, more particularly, to a device for retrieving a closure 
device from a repaired site in the body of a patient in cases where the 
recovery of a condition of patient is not so well after repair operation 
of vascular defects or cardiac defects or where the closure device has 
fallen away or dislodged after operation. 
At the present time, Fontan operations have been used for repair operations 
of complex cardiac anomalies such as single ventricle. In this operation, 
a single ventricle is used for the systemic circulation system, and for 
pulmonary circulation a vein of the systemic circulation system is 
directly connected to a pulmonary artery, whereby cardiac function is 
repaired. However, this operation frequently makes it difficult to perform 
postoperative management since a considerable decrease of cardiac output 
may occur because of increase of a pulmonary vascular resistance or 
transient ventricular hypofunction. The increase of pulmonary vascular 
resistance is caused by spasm of the pulmonary circulation system. 
To avoid the increase of pulmonary vascular resistance and the considerable 
decrease of cardiac output, it is general practice for the above operation 
to form a small fenestration or perforation of about 4 mm between atria 
(most cases, the interatrial septum is made of an artificial membrane), 
thereby allowing the blood to flow through the small fenestration or 
perforation. This procedure followed by formation of the small 
fenestration or perforation is a Fontan fenestration. The closure 
treatment of the small fenestration after Fontan fenestration is mainly 
carried out by surgical operation. However, this surgical operation is 
followed by thoracotomy of a patient in addition to the treatment of the 
affected area. Thus, such surgical incision is a great burden to a 
patient. In particular, in case of a child patient, this burden is 
considerably large. 
Recently, percutaneous transluminal therapeutic catheterization has been 
adopted as a noninvasive procedure to repair endocardial defects. For 
example, closure of atrial septal defects is carried out by transveneously 
inserting an intercardiac catheter into the heart and occluding the defect 
with an occluder. Further, the percutaneous transluminal therapeutic 
catheterization is applied to closure treatment of the small fenestration 
after Fontan fenestration with a closure device. 
However, in case of the closure treatment of the small fenestration after 
Fontan fenestration with the closure device of the prior art, adhesion of 
thrombus may result from a large closure plate. Thus, there is a high risk 
of complications. Further, in cases where the closure device has fallen 
away or dislodged after operation, it is difficult to retrieve the closure 
device due to shape or size of the closure device. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a device for retrieval 
of defect closure devices, especially suitable for retrieval of an 
improved defect closure device for transcatheter operations, which has now 
been developed by the present inventors and is illustrated in FIG. 6. This 
improved defect closure device comprises an easily foldable closure member 
31 with a shape-restoring force, an easily inflective fixing member 32 for 
fixing the closure member 31 to a tissue surrounding a defect aperture, 
and an easily inflective elastic member 33 for holding the closure member 
and the fixing member in close proximity to one another, the elastic 
member being respectively fixed at either end thereof to the fixing member 
and closure member. This closure device enables safe and reliable closure 
of fenestration and is simple in configuration, easy to operate, easy to 
retrieve and less in adhesion of thrombus. 
According to the present invention, the above object is achieved by 
providing a device for retrieval of defect closure devices, which 
comprises a closure-catch catheter having at a distal end thereof a 
closure-catching means and at a proximal end thereof a grip for operating 
the closure-catching means, and an elongated sheath having a lumen and 
being provided at the proximal end thereof with a lateral injection tube 
and hemostatic means, said catheter being moveably insertable in the 
lumen. 
The closure-catching means is preferably made into an arrowhead or a 
configuration which is not transformed when retrieving the closure device 
out of the patient's body after is caught of the closure device. 
Further scope of applicability of the present invention will become 
apparent from the detailed description given hereinafter. However, it 
should be understood that the detailed description and specific examples, 
while indicating preferred embodiments of the invention, are given by way 
of illustration only, since various changes and modifications within the 
spirit and scope of the invention will become apparent to those skilled in 
the art from this detailed description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1, there is shown a device for retrieval of defect 
closure devices according to the present invention. The device comprises a 
closure-catch catheter 1 for catching a closure device and an elongated 
sheath 2 having a lumen 21 for holding the catheter 1 inserted therein. 
The closure-catch catheter 1 is provided at a distal end thereof with 
closure-catching means 11 for catching the closure device and at a 
proximal end thereof with a finger grip 12 for manipulating the catheter 1 
with a finger. The elongated sheath 2 has a lumen 21 holding the 
closure-catch catheter 1 movably inserted therein and is provided at a 
proximal end thereof with a lateral injection tube 22 and hemostatic means 
such as packing 24 or O-ring. 
Preferably, closure-catching means 11 is formed into an arrowhead or a like 
configuration which does not change in shape during retrieval of the 
closure device 3. 
The closure-catch catheter 1 is an elongated solid member provided at a 
distal end thereof with means 11 for catching closure device and at a 
proximal end thereof with a finger grip 12 for manipulating the catheter 1 
with a finger. As a material for closure-catch catheter 1, there may be 
used one or more materials selected from the group consisting of 
fluoroplastics such as polytetrafluoroethylene; synthetic resins such as 
polypropylene, polyethylene, polyester and the like; and meshed or coiled 
stainless steels such as SUS 304. 
The sheath 2 is an elongated tubular member having a lumen 21 which enables 
the catheter 1 to be removably inserted thereinto and being provided at a 
proximal end thereof with a connector 23 having an insertion hole 231 for 
the catheter 1. The connector 23 is provided at its lateral with a side 
port 25 and at a proximal end with a threaded bore formed coaxially with 
the lumen of the connector 23. The side port 25 is communicated with the 
lumen 21 of the sheath 2 and connected with a lateral infusion tube 22 
through which a heparinized physiological saline or the like solution is 
infused into the blood vessel through the sheath 2 to prevent blood 
coagulation during retrieve of the closure device. 
The connector 23 is further provided with a hemostatic means or hemostatic 
valve to prevent the blood leakage during retrieve of the closure device. 
In this embodiment, the hemostatic means is composed of a packing 24 with 
a through-hole at the center thereof. The packing 24 is arranged in the 
threaded bore of the connector 23 and fixed within the lumen of the 
connector 23 by a screw bolt 232 with a through-hole at the center thereof 
to form a hermetic seal between the catheter 1 and connector 23. 
As a material for the sheath, there may be used a material similar to those 
used for the closure-catch catheter 1. Preferred materials are mesh or 
coiled stainless steels such as SUS 304, which are not deformed by stress 
acting in the longitudinal direction of the sheath. 
Explanation will be made on how to use the device for retrieval of defect 
closure devices according to the present invention, making reference to 
FIGS. 2-5. 
Firstly, the device W for retrieval of defect closure devices is inserted 
into an elongated guide sheath 4 which has been previously introduced into 
the right atrial of a patient through a femoral vein of the right leg of 
the patient, and then introduced into the right atrial of the patient 
(FIG. 2). The closure-catching means 11 of the closure-catch catheter 1 is 
pushed into the guide sheath 4 so that it penetrates the closure member 31 
of the closure device 3 at a position close to the frame 311 of the 
closure device 3. The sheath 2 is then pushed out of the guide sheath 4 
until the distal end of the sheath 2 comes into contact with the closure 
device 3 (FIG. 3). When the catheter 1 is pulled back under such a 
condition, the closure-catching means 11 catches the frame 311 of the 
closure member 31 at the arrowhead portion thereof so that the closure 
device 3 is folded up and pulled in the sheath 2 (FIG. 4). By further 
pulling back the closure-catch catheter 1, the elastic member 33 is 
inflected in the longitudinal direction thereof and then the fixing member 
32 is folded up and pulled in the sheath 2 (FIG. 5). 
As will be understood from the above, it is possible with the device of the 
present invention to retrieve the defect closure devices from the repaired 
site in the body of a patient in cases where the defect-closure device has 
fallen away or dislodged after operation. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the invention, and all such modifications as 
would be obvious to one skilled in the art are intended to be included 
within the scope of the following claims.