Procedure and balloon catheter system for relieving arterial or veinal restrictions without exchanging balloon catheters

Claim 1

A system for performing a medical procedure comprising: a) a first, relatively small diameter, balloon catheter having a catheter portion, a balloon portion, a proximal end and a distal end, with said balloon portion being located at or near said distal end, in said passageway; b) removable fitting means at or near the proximal end of said first balloon catheter for attachment thereto of fluid pressure application means; c) a second, larger diameter balloon catheter having a catheter portion, a balloon portion, a proximal end, a distal end, with said balloon portion being located at or near said distal end, d) sliding guide means at or near the distal end of said second balloon catheter, said sliding guide means having a distal end and a proximal end with a passageway therethrough from the distal to the proximal end thereof, which passageway is of such size as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being not longer than about 1/2 the overall length of said second balloon catheter and is comprised of a ring at the distal end of said second balloon catheter.

Claim 2

A system for performing a medical procedure comprising: a) a first, relatively small diameter, balloon catheter having a catheter portion, a balloon portion, a proximal end and a distal end, with said balloon portion being located at or near said distal end, in said passageway; b) removable fitting means at or near the proximal end of said first balloon catheter for attachment thereto of fluid pressure application means; c) a second, larger diameter balloon catheter having a catheter portion, a balloon portion, a proximal end, a distal end, with said balloon portion being located at or near said distal end, d) sliding guide means at or near the distal end of said second balloon catheter, said sliding guide means having a distal end and a proximal end with a passageway therethrough from the distal to the proximal end thereof, which passageway is of such size as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being not longer than about 1/2 the overall length of said second balloon catheter and is comprised of a ring at the distal end of said second balloon catheter.

Claim 3

A system for performing a medical procedure comprising: a) a first, relatively small diameter, balloon catheter having a catheter portion, a balloon portion, a proximal end and a distal end, with said balloon portion being located at or near said distal end, said first balloon catheter has a captive safety guide; b) removable fitting means at or near the proximal end of said first balloon catheter for attachment thereto of fluid pressure application means; c) a second, larger diameter balloon catheter having a catheter portion, a balloon portion, a proximal end, a distal end, with said balloon portion being located at or near said distal end; d) sliding guide means at or near the distal end of said second balloon catheter, said sliding guide means having a distal end and a proximal end with a passageway therethrough from the distal to the proximal end thereof, which passageway is of such size as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being not longer than about 1/2 the overall length of said second balloon catheter.

Claim 4

A system for performing a medical procedure comprising: a) a first, relatively small diameter, balloon catheter having a catheter portion, a balloon portion, a proximal end and a distal end, with said balloon portion being located at or near said distal end, said first balloon catheter has a captive safety guide; b) removable fitting means at or near the proximal end of said first balloon catheter for attachment thereto of fluid pressure application means; c) a second, larger diameter balloon catheter having a catheter portion, a balloon portion, a proximal end, a distal end, with said balloon portion being located at or near said distal end; d) sliding guide means at or near the distal end of said second balloon catheter, said sliding guide means having a distal end and a proximal end with a passageway therethrough from the distal to the proximal end thereof, which passageway is of such size as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being not longer than about 1/2 the overall length of said second balloon catheter.

Claim 5

A system for performing a medical procedure comprising: a) a first, relatively small diameter, balloon catheter having a catheter portion, a balloon portion, a proximal end and a distal end, with said balloon portion being located at or near said distal end; b) removable fitting means at or near the proximal end of said first balloon catheter for attachment thereto of fluid pressure application means; c) a second, larger diameter balloon catheter having a catheter portion, a balloon portion, a proximal end, a distal end, with said balloon portion being located at or near said distal end; d) sliding guide means at or near the distal end of said second balloon catheter, said sliding guide means having a distal end and a proximal end with a passageway therethrough from the distal to the proximal end thereof, which passageway is of such size as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being not longer than about 1/2 the overall length of said second balloon catheter and is comprised of a flexible loop at the distal end of said second balloon catheter.

Claim 6

A system for performing a medical procedure comprising: a) a first, relatively small diameter, balloon catheter having a catheter portion, a balloon portion, a proximal end and a distal end, with said balloon portion being located at or near said distal end; b) removable fitting means at or near the proximal end of said first balloon catheter for attachment thereto of fluid pressure application means; c) a second, larger diameter balloon catheter having a catheter portion, a balloon portion, a proximal end, a distal end, with said balloon portion being located at or near said distal end; d) sliding guide means at or near the distal end of said second balloon catheter, said sliding guide means having a distal end and a proximal end with a passageway therethrough from the distal to the proximal end thereof, which passageway is of such size as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being not longer than about 1/2 the overall length of said second balloon catheter and is comprised of a flexible loop at the distal end of said second balloon catheter.

Claim 11

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means near said distal end, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) retracting the balloon portion of said second balloon catheter from said section of said fluid passageway, k) relocating the balloon portion of said first balloon catheter from said second section of said fluid passageway, l) expanding the balloon portion of said first balloon catheter, m) reattaching said fitting to said first balloon catheter before expanding the balloon portion thereof, n) collapsing the balloon portion of said balloon catheter, o) sliding said sliding guide means along the catheter portion of said first balloon catheter until the balloon portion of said second balloon catheter is within said second fluid passage section, p) expanding the balloon portion of said second balloon catheter; q) collapsing the balloon portion of said second balloon catheter, and r) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 12

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means near said distal end, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) retracting the balloon portion of said second balloon catheter from said section of said fluid passageway, k) relocating the balloon portion of said first balloon catheter from said second section of said fluid passageway, l) expanding the balloon portion of said first balloon catheter, m) reattaching said fitting to said first balloon catheter before expanding the balloon portion thereof, n) collapsing the balloon portion of said balloon catheter, o) sliding said sliding guide means along the catheter portion of said first balloon catheter until the balloon portion of said second balloon catheter is within said second fluid passage section, p) expanding the balloon portion of said second balloon catheter; q) collapsing the balloon portion of said second balloon catheter, and r) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 17

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means near said distal end, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, wherein the catheter portion of said second balloon catheter has a stiffening wire lumen therein and wherein a removable stiffening wire is provided, further comprising the steps of inserting said stiffening wire in said stiffening wire lumen when reduced flexibility is desired and removing or partially retracting said stiffening wire when increased flexibility is desired, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 18

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means near said distal end, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, wherein the catheter portion of said second balloon catheter has a stiffening wire lumen therein and wherein a removable stiffening wire is provided, further comprising the steps of inserting said stiffening wire in said stiffening wire lumen when reduced flexibility is desired and removing or partially retracting said stiffening wire when increased flexibility is desired, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 19

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, said first balloon catheter further having a captive safety guide, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means near said distal end, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 20

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, said first balloon catheter further having a captive safety guide, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means near said distal end, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 21

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means comprised of a ring at said distal end of said second balloon catheter, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 22

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means comprised of a ring at said distal end of said second balloon catheter, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 23

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means comprised of a flexible loop at said distal end of said second balloon catheter, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) removing said first balloon catheter and said second balloon catheter from said passageway.

Claim 24

A method for performing a medical procedure involving enlarging the flow passage of a section of a fluid passageway within the patient's body comprising: a) placing a first, relatively small diameter balloon catheter in said passageway; said first balloon catheter having a catheter portion and a balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said first balloon catheter having a fitting at or near its proximal end for connection thereto of fluid pressure application means, b) advancing said first balloon catheter through said passageway until said balloon portion is located within said section to be enlarged, c) expanding the balloon portion of said first balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber, d) reducing the pressure in said first balloon catheter and withdrawing fluid from and thereby collapsing said first balloon chamber prior to feeding said second balloon portion into said passageway section, e) removing said fitting from said first balloon catheter, f) placing a second, larger diameter balloon catheter over the catheter portion of said first balloon catheter, said second balloon catheter having a catheter portion and balloon portion and a proximal end and a distal end, with said balloon portion located at or near said distal end, said second balloon catheter further having sliding guide means comprised of a flexible loop at said distal end of said second balloon catheter, which sliding guide means is so sized and positioned as to accommodate therein and permit sliding passage therethrough of the balloon portion and the catheter portion of said first balloon catheter, said sliding guide means being further characterized in that it has a distal end and a proximal end and is not longer than about 1/2 the overall length of said second balloon catheter, g) feeding the proximal end of the catheter portion of said first balloon catheter through said sliding guide means, from the distal end thereof to the proximal end thereof, and continuing to feed said second balloon catheter into said passageway and along said first balloon catheter until said balloon portion of said second balloon catheter is within the passageway section to be enlarged, h) expanding the balloon portion of said second balloon catheter by forcing fluid under pressure through the catheter portion thereof into the balloon chamber thereof, i) reducing the pressure in said second balloon catheter and withdrawing fluid from and thereby collapsing the balloon chamber thereof, and j) removing said first balloon catheter and said second balloon catheter from said passageway.