DUAL DILATATION CATHETER ASSEMBLY AND MINIATURE BALLOON DILATATION CATHETER FOR USE THEREWITH

Abstract: A dual dilatation catheter assembly (11) having a first dilatation catheter (12) and a second dilatation catheter (13). The first dilatation catheter comprised of a first tubular element (16) having a lumen (17) extending therethrough and a second tubular element (18) extending coaxially over the first tubular element and forming a lumen (19) extending between the first and second tubular elements. A balloon (21) is carried by the second tubular element and has its interior in communication with the lumen extending between the first and second tubular elements. The second dilatation catheter extends through the lumen in the first tubular element of the first dilatation catheter and is comprised of a flexible elongate tubular element having a lumen extending therethrough, an inflatable balloon carried by the first tubular element of the second dilatation catheter, the balloon of the second dilatation catheter having a collapsed diameter which is less than the interior diameter of the lumen of which is less than the interior diameter of the lumen of the first tubular element of the first dilatation catheter whereby the second dilatation catheter can be inserted and removed from the first dilatation catheter.

Description: This invention relates to a dual dilatation catheter assembly and to a miniature balloon dilatation catheter for use therewith. Balloon dilatation catheters have heretofore been provided. However, it has been difficult with such catheters to dilate stenoses in blood vessels which have very small openings therein. There is therefore a need for a dilatation catheter which can be utilized for such situations. The present invention provides a dual dilatation catheter assembly and miniature balloon dilatation catheter for use therewith. In general, the dual dilatation catheter assembly of the present invention consists of first and second catheters. The first catheter consists of a first flexible elongate tubular element having a lumen extending therethrough and a second flexible tubular element extending coaxially over the first tubular element and forming a lumen extending between the first and second tubular elements. A balloon is carried by the second tubular element and has its interior in communication with the lumen extending between the first and second tubular elements. The second catheter consists of a first flexible elongate tubular member having a lumen extending therethrough. A balloon is carried by the first tubular element of the second catheter and has its interior in communication with the lumen in the first flexible elongate tubular element of the second catheter. The balloon of the second catheter has a collapsed diameter less than the internal diameter of the lumen in the first tubular element of the first catheter so that the second catheter can be inserted through the lumen in the first tubular element of the first catheter. The present invention is further described by way of example only, with reference to the accompanying drawings, in which; Figures 1A and Figure 1B show a side elevational view of a dual dilatation catheter assembly incorporating the present invention. Figure 2 is an enlarged cross sectional view of a portion of the catheter assembly shown in Figures 1A and 1B. Figure 3 is a view partially in cross section of the miniature balloon dilatation catheter assembly shown in Figures 1A and 1B. Figure 4 is an enlarged cross sectional view of the distal extremity of the miniature balloon dilatation catheter shown in Figure 3. Figure 5 is a side elevational view of the rotation limiting device shown in Figure 1A. Figure 6 is a partial cross-sectional view showing another embodiment of the rotation limiting device shown in Figure 1A. More particularly, as shown on the drawings, the dual catheter assembly 11 consists of a first dilatation catheter 12 and a second or miniature dilatation cathe­ ter 13. The first dilatation catheter 12 consists of a first flexible elongate tubular element 16 having a lumen 17 extending therethrough. It also consists of a second flexible elongate tubular element 18 which extends over the first tubular element and is coaxial therewith. An annular lumen 19 is formed between the first and second tubular elements 16 and 18 and extends longitudinally thereof. A balloon 21 is carried by the second tubular element and, as shown, can be formed integral therewith and has its interior in communication with the lumen 19 extending between the first and second tubular elements 16 and 18. Means is provided for visually indicating the distal and proximal extremities of the balloon 21 and consists of a pair of bands 23 formed of a suitable material e.g. gold which are carried on the exterior surface of the first tubular element 16. An additional band 24 is carried by the distal extremity of the first and second tubular elements 16 and 18 and is disposed between the same. The first and second tubular elements 16 and 18 are formed of a suitable plastic material e.g. polyethylene. The outer or second tubular element 18 is formed of a heat shrinkable polyethylene and its distal extremity is shrunk onto the distal extremity of the first tubular element 16 to form a liquid-tight seal. The proximal extremities of the first and second tubular elements 16 and 18 are mounted in a rotary joint 26. A side arm adapter 27 is mounted on the rotary joint 26 and is provided with a side arm 28 which is provided with a Luer fitting 29. The side arm 28 is in communication with the lumen 19 formed between the first and second tubular elements. The first tubular element 16 extends through the central or main arm 31 of the side arm adapter 27 and extends into a fitting 32 which is provided with a thumb screw 33. The thumb screw 33 is adapted to engage an O-ring 34 to form a liquid-­ tight seal with respect to the second dilatation catheter 13 which extends therethrough and which extends through the lumen 17 of the first tubular element 16 of the first dilatation catheter 12. The first dilatation catheter 12 can have suitable dimensions. For example, the catheter 12 itself can have a length of approximately 135 centimeters. The first tubular element 16 can have an outer diameter of .040 inches (1.02mm) and an inner diameter of .030 inches (0.76mm). The necked down portion of the element 16 within the balloon can have an outside diameter of .029 inches (0.74mm) and an inside diameter of .023 inches (0.59mm). The second tubular element 18 can have an outside diameter of .056 inches (1.42mm) and an inside diameter of .046 inches (1.17mm). The balloon 21 can have a length of 25 millimeters and the distal extremity of the first and second tubular elements 16 and 18 can have a length of approximately 9 millimeters. The distal extremity of tip of the first dilatation catheter 12 can have a maximum diameter of .045 inches (1.14mm). The balloon 21 can have a diameter of 3 millimeters. The second or miniature dilatation catheter 13 consists of a flexible elongate tubular element 41 which is formed of several sections 41a, 41b and 41c and through which a lumen 42 extends. The section 41a is formed of stainless steel having an outside diameter of approximately .014 inches (0.35mm) with a wall thickness of .003 inches (0.08mm) so that the inside diameter is approximately .008 inches (0.20mm). The distal extremity of the portion 41a is ground down to a smaller dimension as, for example, an outside diameter of .010 inches (0.25mm). The exterior surface of the protion 41a is coated with an unctuous material such as Teflon. The other portion 41b of the flexible elongate tubular element 41 consists of a plastic tube of a suitable type e.g. polyethylene of a length ranging from 20 to 30 centimeters. This tube has an outside diameter of .014 inches (0.27mm) and is mounted by friction fit on the distal extremity of the portion 41a. A balloon 43 is carried by the portion 41b and as shown is formed integral therewith and has its interior in communication with the lumen 42. The balloon 43 can have a suitable outside diameter such as 1.8 millimeters and a suitable length such as approximately 1.5 centimeters. A coil 46 formed of a suitable material, e.g. a platinum/tungsten alloy has its proximal extremity secured to the distal extremity of the portion 41b of the tubular element 41 by suitable means such as an adhesive 47. A semi-spherical tip 48 formed of a suitable material, e.g. gold is provided on the distal extremity of the coil 46. A guide wire 49 extends through the lumen 42 and is bonded into the adhesive 47 as well as the tip 48. The guide wire 49 can have a suitable dimension such as .005 inches (0.13mm). A guide wire 49 of a suitable diameter such as .005 inches (0.13mm) extends through the lumen 42 and through the balloon 43 and is bonded to the distal extremity of the portion 41b by the adhesive 47 and also to the tip 48. The guide wire 49 extends to the proximal extremity of the tubular element 41 and extends through a fitting 51 which is secured to the tubular element 41 by suitable means e.g. solder 52. The second or miniature dilatation catheter can have a suitable length as, for example, 175 centimeters. The fitting 51 is adapted to be threaded in a threaded extension 53 of a rotation limiting device 56. The guide wire 49 extends through and is secured to a knob 57 of the rotation limiting device 56 by suitable means such as a set screw 58. The knob 57 is rotatably mounted on a rigid tube 59 which has a flow passage 61 extending therethrough. The rigid tube 59 is mounted in a cylindrical block 62 which is provided with parting lines 63, 64 and 66. The parting lines 63 and 64 are provided in the block 62 at the points where O-rings 67 and 68 are disposed. The O-rings 67 and 68 provide liquid-tight seals between the block 62 and the rigid tube 59. The parting line 66 is provided to facilitate the insertion of the torque knob 57 as well as three rotation limiting disks, 71, 72 and 73. Each of the disks 71, 72 and 73, as well as the torque knob 57, is provided with an extension (not shown) which extends into an arcuate recess provided in the adjacent ring. The disks 71, 72 and 73 are rotatably mounted upon the rigid tube 59 and permit limited rotation, as for example, three complete rotations of the torque knob 57 with respect to the block 62. The reader is referred to our application of today's date describing the said rotation limitation system, a copy of which is filed herewith but does not form part of the presently published specification. The block 62 is provided with a cylindrical recess 74 which receives the knurled knob 57 as well as the disk 71, 72 and 73. A cut-out 76 is also provided in the block 62 and facilitates engagement of the knurled knob 57 by one of the fingers of the hand. The block 62 is provided with flow passages 77 and 78 which are in communication with the flow passage 61 provided in the rigid tube 59. The block 62 is provided with an internally threaded bore 79 which receives an externally threaded extension 81 which forms a part of a hand-­ operated inflating device 86 of a type which can utilize a gas e.g. carbon dioxide for inflating the balloon 43. The inflating device 86 consists of a housing 87 which has a piston rod 88 slidably disposed therein which carries a piston 89. The piston rod 88 is adapted to be operated by a button 91 carried by the proximal extremity of the same. The housing 87 carries a pair of side arms 92 which are adapted to be engaged by the fingers of the hand while the button 91 is engaged by the palm of the same hand so that the piston rod 88 can be pushed inwardly. The piston 89 is slidably mounted in a cylinder 93 which is carried by the housing and a portion of which can be viewed through the elongate openings 94 provided on opposite sides of the housing 87. A one-way valve 96 of a suitable type such as a duckbill valve is mounted on the cylinder 93 in a suitable position, as for example, at a point in which three cubic centimeters of volume are available from the one-way valve 96 to the distal extremity of the cylinder 93. An inlet fitting 97 is mounted on the cylinder 93 adjacent the proximal extremity of the same in a position which is rotated by a suitable angle e.g. 90° to 180° from the position where the one-way valve 96 is located. Cooperative means is carried by the piston rod 88 and the cylinder 93 so as to prevent uncovering of the inlet fitting 97 except in a predetermined angular position of the piston rod 88 with respect to the cylinder 93. For this purpose, an elongate slot 101 is provided in the piston rod 88 which extends from the button 91 to near the piston 89. The slot 101 consists of a portion 101a which extends from the button 91 for a substantial length of the piston rod and adjoins a portion 101b which extends at right angles to the portion 101a. Portion 101b adjoins a further portion 101c which extends at right angles to the portion 101b and is parallel to the portion 101a. A pin 102 is provided in the housing 87 and is seated in the slot 101 and limits the movement of the piston rod 88 as hereinafter described. A pressure gauge 106 is mounted on the distal extremity of the housing 87 and is in communication with the cylinder 93 and with the externally threaded extension 81. Operation of the miniature or second dilatation catheter 13 in conjunction with the first dilatation catheter 12 in the dual dilatation catheter assembly 11 may now be briefly described as follows. Let it be assumed that the first dilatation catheter has been inserted into a vessel of a human being and that the stenosis which has been located is too small for the balloon 21 to enter the stenosis. The second balloon dilatation catheter 13 is prepared for use. A suitable source of carbon dioxide, as for example, a 50 cc syringe (not shown) of carbon dioxide is placed in the fitting 97 of the inflating device 86. While holding the side arms 92 in one hand, the button 91 is grasped with the other hand and the piston rod 88 is retracted through the length of the portion 101a of the slot 101. When the end of the portion 101a is reached, the button 91 is rotated through 90° so that the pin travels in the portion 101b. As soon as this travel has been accomplished, the piston rod 88 can be further retracted by the pin 102 traveling in the portion 101c of the slot. This movement of the pin 102 in the portion 101c permits the piston 89 to clear the inlet fitting 97. The cylinder 93 is then filled and purged with the 50 cubic centimeters of carbon dioxide with the excess carbon dioxide escaping through the one-way valve 96. As soon as purging with the carbon dioxide gas has been accomplished, the inflating device 86 is grasped by the hand and the piston rod 88 is pushed inwardly by the fingers of the hand grasping the side arms 92 and the palm of the same hand engaging the button 91. Travel of the piston 89 occludes the inlet 97 so that further carbon dioxide gas cannot be introduced into the cylinder 93. The button 91 is then rotated through 90° to cause the pin 102 to travel in the portion 101b of the slot. Thereafter, the piston rod 88 is advanced so that the pin 102 travels in the portion 101a of the slot 101. As the piston moves forwardly, excess carbon dioxide is discharged through the one-way valve 96. This discharge continues until the piston 89 reaches the one-way valve 96 to occlude it. As soon as the purging operation has been completed as hereinbefore described, the second dilatation catheter 13 is ready to be introduced into the first dilatation catheter 12. For this purpose, the first dilatation catheter 12 is removed a short distance so that it is away from the stenosis for which it is wished to dilate and the guide wire, if one has been used for positioning the first dilatation catheter 12, is removed. The second dilatation catheter 13 can now be inserted through the fitting 32. The advance of the second dilatation catheter 13 can be facilitated by use of the torque knob 57 to cause rotation of the guide wire 49 which in turn can be utilized for causing movement of the spring-like tip provided by the coil 46. So that undue stress is not placed on the coil 46 or undue wrapping of the balloon 43 does not occur, the rotation limiting device 56 limits the rotation to not exceed, for example, three or four turns. After the tip of the second dilatation catheter 13 has been advanced into the stenosis, and the balloon 43 positioned properly, the balloon 43 can be inflated. The piston rod 88 is then depressed by grasping the side arms 92 by the fingers and the button 91 by the palm of the same hand to push it inwardly. As the piston 89 is advanced, the carbon dioxide within the cylinder 93 will be discharged through the one-way valve 96. This continues until the piston 89 occludes the one-way valve 96 so that there remains in the cylinder a predetermined volume of carbon dioxide gas, as for example, approximately three cubic centimeters. Further, depression of the piston rod 88 and the piston 89 thereby causes this remaining three cubic centimeters of carbon dioxide gas to be introduced into the balloon 43 to inflate the balloon to dilate the stenosis. By utilizing carbon dioxide very substantial pressures up to 200 psi can be generated. Gas, rather than a liquid, has been utilized as an inflating medium for the balloon 43 because of the very small diameter of the passageway or lumen 42 extending into the balloon 43. Carbon dioxide is a preferable gas because it can be more readily assimilated in the blood stream. After the stenosis has been widened sufficiently, the second dilatation catheter can be removed from the stenosis and also from the first dilatation catheter. Thereafter, if necessary a guide wire can be reintroduced into the first dilatation catheter 12 and the first dilatation catheter advanced into the stenosis until the balloon 21 comes into alignment with the stenosis. Thereafter the balloon 21 can be operated by utilizing a radiographic contrast liquid which is introduced through the side arm 28. After the balloon 21 has been inflated one or more times to dilate the stenosis, the first dilatation catheter 12 can be removed. By limiting the quantity of carbon dioxide which can be introduced into the balloon 43, the amount of gas present in the balloon 43 is insufficient to cause damage to the patient in the event of rupture of the balloon. Thus it can be seen that the dual catheter assembly can be utilized safely and can be utilized for penetrating stenoses having minimal openings in the same. It should be appreciated that if desired, the miniature dilatation catheter 13 can be utilized by itself. Since a guide wire 49 has been provided in conjunction with the secon dilatation catheter 13, the tip or coil 46 can be provided with a slight bend and can be rotated through a number of rotations as determined by the rotation limiting device 56 to facilitate guiding the second dilatation catheter 13 into the desired location. This rotation capability of the second dilatation catheter 13 can also be utilized when it is being used in conjunction with the first dilatation catheter 12 as hereinbefore explained. Another embodiment of a portion of the dual catheter assembly 11 is shown in Figure 5 and consists of a rotation limiting device 111. The rotation limiting device 111 consists of a movable body 112 which is provided with an externally threaded extension 113 which is threaded into the fitting 51. The movable body 112 is provided with a cylindrical recess 114 which receives a stem 116 having a flow passage 117 extending therethrough. The stem 16 is formed integral with a fixed body 118 through which the flow passage 117 extends. The fixed body 118 is provided with a threaded bore 119 which receives the externally threaded extension 81 of the inflating device 86. Three rotating disks 121 are provided which are rotatably mounted upon the stem 116. These disks 121 are provided with protrusions (not shown) which seat in grooves (not shown) in the manner hereinbefore described to again limit the amount of rotation of the movable body 112 with respect to the fixed body 118. The guide wire 49 is secured to the movable body 112 in a suitable manner such as by securing it between the fitting 51 and the extension 113. It can be seen that by utilizing a rotation limiting device 111 of the type shown in Figure 5 that the entire second dilatation catheter 13 can be rotated with the guide wire 49 to cause rotation of the flexible tip of the catheter 13. The guide wire 49 provides torsional rigidity to ensure that rotation of the tip will occur. It is apparent from the foregoing that there has been provided a dual dilatation catheter assembly that includes a miniature balloon dilatation catheter which can be guided by the use of a rotation flexible tip. Because of the small size of the miniature dilatation catheter, carbon dioxide is utilized as an inflating medium for the balloon. Safety features are provided in the device used for inflating the balloon of the miniature balloon dilatation catheter to ensure that not more than a predetermined quantity of carbon dioxide can be introduced into the body for inflation of the balloon. The size of the miniature dilatation catheter is such that it can be inserted into a conventionally sized dilatation catheter and utilized therewith.

Claims: 1. A dual dilatation catheter assembly for dilating a stenosis in a vessel comprising a first dilatation catheter, a first tubular element having a lumen extending therethrough, a second tubular element extending coaxially over the first tubular element and forming a lumen extending between the first and second tubular elements, a balloon carried by the second tubular element and having its interior in communication with the lumen extending between the first and second tubular elements, a second dilatation catheter extending through the lumen in the first tubular element of the first dilatation catheter, a flexible elongate tubular element having a lumen extending therethrough, an inflatable balloon carried by the flexible tubular element of the second dilatation catheter and having its interior in communication with the lumen of the flexible tubular element of the second dilatation catheter, the balloon of the second dilatation catheter being elongate and for dilating a stenosis, the balloon of the second dilatation catheter having a collapsed diameter which is less than the interior diameter of the lumen of the first tubular element of the first dilatation catheter whereby the second dilatation catheter can be inserted and removed from the first dilatation catheter. 2. A dual dilatation catheter assembly comprising a first dilatation catheter, a first tubular element having a lumen extending therethrough, a second tubular element extending coaxially over the first tubular element and forming a lumen extending between the first and second tubular elements, a balloon carried by the second tubular element and having its interior in communication with the lumen extending between the first and second tubular elements, a second dilatation catheter extending through the lumen in the first tubular element of the first dilatation catheter, a flexible elongate tubular element having a lumen extending therethrough, an inflatable balloon carried by the flexible tubular element of the second dilatation catheter, the balloon of the second dilatation catheter having a collapsed diameter which is less than the interior diameter of the lumen of the first tubular element of the first dilatation catheter whereby the second dilatation catheter can be inserted and removed from the first dilatation catheter, the second dilatation catheter having a flexible tip and a guide wire extending through the lumen in the flexible elongate tubular element of the second dilatation catheter and being secured to the tip whereby the guide wire can be rotated to cause rotation of the tip. 3. An assembly as claimed in claim 1 wherein said flexible elongate tubular element of the second dilatation catheter includes a flexible metal tube and a plastic tube secured tothe metal tube, the balloon of the second dilatation catheter being carried by the plastic tube. 4. A dual dilatation catheter assembly comprising a first dilatation catheter, a first tubular element having a lumen extending therethrough, a second tubular element extending coaxially over the first tubular element and forming a lumen extending between the first and second tubular elements, a balloon carried by the second tubular element and having its interior in communication with the lumen extending between the first and second tubular elements, a second dilatation catheter extending through the lumen in the first tubular element of the first dilatation catheter, a flexible elongate tubular element having a lumen extending therethrough, an inflatable balloon carried by the flexible tubular element of the second dilatation catheter, the balloon of the second dilatation catheter having a collapsed diameter which is less than the interior diameter of the lumen of the first tubular element of the first dilatation catheter whereby the second dilatation catheter can be inserted and removed from the first dilatation catheter, the second dilatation catheter having said flexible elongate tubular element of the second dilatation catheter includes a flexible metal tube and a plastic tube secured to the metal tube, the balloon of the second dilatation catheter being carried by the plastic tube, said second dilatation catheter also including a flexible tip bonded to the distal extremity of the balloon together with a guide wire secured to the flexible tip for causing limited rotation of the flexible tip. 5. A miniature balloon dilatation catheter assembly for dilating a stenosis in a vessel comprising a flexible elongate tubular element having a lumen extending therethrough, a balloon carried by the flexible elongate tubular element and being in communication with the lumen extending through the tubular element, and means for inflating the balloon with a limited predetermined quantity of carbon dioxide, optionally further comprising a flexible tip secured to the distal extremity of the balloon and a guide wire secured to the tip and extending through the balloon and the lumen of the flexible elongate element. 6. A dilatation catheter as in claim 5 wherein the flexible elongate element is formed of a section of a metal tube and a section of plastic and wherein the balloon is formed integral with the plastic section. 7. An assembly as claimed in claim 2 which further comprises a means for introducing a radiographic contrast liquid into the balloon of the first dilatation catheter and means for introducing a gas into the balloon of the second dilatation catheter. 8. An assembly as claimed in any one of claims 2, 5 or 6 which further comprises means connected to the guide wire for providing limited rotation of the guide wire. 9. An assembly as claimed in claim 8 wherein said means for providing limited rotation of the guide wire includes means for causing rotation of the guide wire independently of the rotation of the proximal extremity of the first tubular element of the second or miniature dilatation catheter. 10. An assembly as claimed in claim 8 wherein said means for providing limited rotation of the guide wire includes means for causing rotation of the guide wire and the first tubular element of the second or miniature dilatation catheter. 11. An assembly as claimed in claim 5 or claim 6 wherein said means for introducing gas, for example carbon dioxide, into the balloon of the scecond dilatation catheter or miniature catheter includes a cylinder, a piston slidably mounted in the cylinder, and means carried by the piston and the cylinder for preventing introduction of more than a limited predetermined quantity of gas, optionally including a one-way valve means venting to the environment more than a limited predetermined quantity of carbon dioxide to be introduced into the balloon of the second dilatation catheter. 12. An assembly as claimed in claim 11 wherein the one-way valve means is carried by the cylinder and is spaced from the distal extemity of the cylinder so that a predetermined volume of the cylinder corresponding to the predetermined volume of gas extends beyond the one-way valve, whereby when the cylinder is filled with gas and the piston is advanced, the gas in the cylinder which is in excess of that of the predetermined volume proximal of the one-way valve is vented to the atmosphere through the one-way valve. 13. An assembly as claimed in claim 12 which further comprises a housing carrying the cylinder, a plunger extending into the h ousing and being secured to the piston in the cylinder, an inlet fitting connected to the cylinder at a proximal extremity of the cylinder, the piston being movable in the cylinder so that it clears the inlet fitting and the distal extremity of the cylinder so that the cylinder can be filled with gas. 14. An assembly as claimed in claim 13 which further comprises means carried by the piston rod for preventing retraction of the piston in the cylinder beyond the inlet fitting until the piston rod is rotated through a predetermined angle. 15. An assembly as claimed in claim 14 wherein said means for preventing movement of the piston beyond the inlet fitting unless the piston rod is rotated through a predetermined angle includes cooperative pin and slot means carried by the piston rod and the housing, the pin and slot means including a slot which has first, second and third portions with the first portion extending longitudinally of the piston rod, the second portion extending at a substantial angle with respect to the longitudinal axis of the piston rod and the third portion extending in a direction longitudinally of the piston rod.

Inventors: MAR, CRAIG EVAN, SAMSON, WILFRED JOSEPH, WILLIAMS, RONALD G.
Applicants: ADVANCED CARDIOVASCULAR SYSTEMS, INC.
Application year: 1986
Main classification: A61M29
IPC codes: A61B17, A61M25, A61M29