Variable speed stent delivery system

• US 7,935,141 B2
• Filed: 08/16/2006
• Issued: 05/03/2011
• Est. Priority Date: 08/17/2005
• Status: Active Grant

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Randall, Michael, Fulkerson, John
• Primary Examiner(s): Manahan; Todd E
• Assistant Examiner(s): COLELLO, ERIN L
• Application Number:
  US11/505,185
• Publication Number:
  US 20070060999A1
• Time in Patent Office: 1,721 Days
• Field of Search: 623/1.11, 623/1.12, 623/1.23, 606/108
• US Class Current: 623/1.11
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/9517 handle assemblies therefor
• CPC Class Codes: A61F 2/966 with relative longitudinal movement between outer sleeve and prosthesis, e.g. using a push rod

Abstract

A delivery system for deploying a medical device, such as a stent, at increasing deployment speed is described. The system comprises a catheter comprising a catheter shaft, a retractable sheath slidably mounted on the catheter shaft, and the device in a compressed state sandwiched between the shaft and sheath. A control handle is included with a housing and knobs for a user to apply a rotary or other force to retract the sheath. The sheath is attached to a slider that is mounted on a slide rod and attached to a drive belt. A take up pulley is provided in the housing and connected to the belt input knob, so that the pulley turns when the knob is turned. The belt is attached to the pulley so that the drive is wound onto the rotating pulley. As the belt winds upon the pulley, the overall outside diameter of the pulley increases, thereby increasing the deployment speed.

Claims

1. A delivery system for deploying a medical device at variable speeds, comprising:

a catheter assembly comprising an elongate shaft and an elongate sheath including a lumen in which the shaft is positioned, wherein the sheath is movable relative to the shaft from an initial position in which the medical device is sandwiched between the sheath and the shaft to a final position in which the medical device is exposed; and

a control handle comprising a connector element attaching an end of the sheath to the control handle and a variable speed mechanism attached to the connector element, wherein the variable speed mechanism includes;

a rotary knob that is operable at a relatively constant input rotation speed to move the connector element from a first position to a second position at a retraction speed that varies from an initial speed to a final speed that is higher than the initial speed, whereby the attached sheath is moved from the initial position to the final position;

a slide rod mating with a passageway in the connector element, whereby the connector element is able to slide along the length of the slide rod;

a take up pulley;

a drive belt attached at a first end to the connector element and at a second end to the take up pulley, wherein the drive belt is wrapped onto a contact surface of the take up pulley when the take up pulley is rotated and moves the attached connector element at the varying retraction speed; and

a translation member rigidly attached to a user input element to rotate with the user input element, wherein the translation member is linked to the take up pulley to rotate at an angular velocity based on the input force, and wherein an overall outer diameter of the take up pulley, comprising an outer diameter of the take up pulley and wrapped portions of the drive belt, increases with rotation of the take up pulley, whereby the angular velocity increases based on the input force with a resultant increase in the retraction speed.

2. The system of claim 1, wherein the retraction speed increases substantially continuously from the initial speed to the final speed.

3. The system of claim 2, wherein the connector element is moved along a linear path and the retraction speed is measured as a linear velocity.

4. The system of claim 1, wherein the variable speed mechanism further comprises an idler pulley mounted within the system to freely rotate and to support the drive belt to pull the connector element toward the idler pulley on the slide rod as the drive belt is wrapped onto the take up pulley.

5. A stent deployment apparatus, comprising:

a shaft having proximal and distal ends;

an expandable stent mounted over the distal end of the shaft;

a retractable sheath slidably mounted on the shaft, the sheath being retractable from a fully extended position in which the stent is covered by the retractable sheath and a fully retracted position in which the stent is exposed;

a take up pulley with a conical contact surface rotating at a fixed user input rotation rate; and

a drive belt linked to the retractable sheath and to the take up pulley such that the drive belt wraps onto the contact surface from a smaller cross sectional portion to a larger cross sectional portion.