Guide extension catheter

A method comprising:

• introducing a guide catheter in vasculature of a patient, wherein the guide catheter extends from a guide catheter proximal end to a guide catheter distal end and defines a guide catheter lumen;
• and
• introducing a guide extension catheter in the guide catheter lumen at the guide catheter proximal end, wherein the guide extension catheter comprises an elongate tube member extending from a proximal end to a distal end and defining a guide extension catheter lumen, a push member mechanically coupled to the proximal end of the elongate tube member, and a manipulation member slidably disposed about an outer perimeter of the push member,
• wherein the push member includes a plurality of segments, each of the plurality of segments having a different shape in cross-section,
• wherein the manipulation member is controllably engageable with the push member along each of the plurality of segments, wherein, when the manipulation member is in an engaged state with the push member the manipulation member transmits an axial force to the push member to enable the push member to transmit the axial force to the elongate tube member, and wherein when the manipulation member is in a disengaged state with the push member, the manipulation member is movable axially in at least one direction along a length of the push member while transmitting substantially no axial force to the push member.

A method comprising:

• introducing a guide catheter in vasculature of a patient, wherein the guide catheter extends from a guide catheter proximal end to a guide catheter distal end and defines a guide catheter lumen;
• and
• introducing a guide extension catheter in the guide catheter lumen at the guide catheter proximal end, wherein the guide extension catheter comprises,
• an elongate tube member extending from a proximal end to a distal end and defining a guide extension catheter lumen, and three portions, each portion having a distinct diameter, wherein a distal portion has a first diameter, a proximal portion has a second diameter which is larger than the first diameter but smaller than a lumen of the guide catheter, and a tapered portion, positioned between the distal portion and the proximal portion, has a variable diameter,
• a push member mechanically coupled to the proximal end of the elongate tube member, wherein the push member includes a plurality of segments, each of the plurality of segments having a different shape in cross-section, and
• a manipulation member slidably disposed about an outer perimeter of the push member, wherein the manipulation member is controllably engageable with the push member along each of the plurality of segments, wherein, when the manipulation member is in an engaged state with the push member the manipulation member transmits an axial force to the push member to enable the push member to transmit the axial force to the elongate tube member, and wherein when the manipulation member is in a disengaged state with the push member, the manipulation member is movable axially in at least one direction along a length of the push member while transmitting substantially no axial force to the push member.