Abstract:
The invention provides a method of intravascular intervention that includes inserting a catheter comprising an extended body into a lumen within tissue of a patient, advancing the catheter to a treatment site, vibrating a proximal end of the catheter with a mechanical vibrator, and treating the treatment site while a distal end of the catheter is vibrating.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of, and priority to, U.S. Provisional Patent Application No. 61/777,394, filed Mar. 12, 2013, and also to U.S. Provisional Patent Application No. 61/777,407, filed Mar. 12, 2013, the contents of each of which are incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention generally relates to systems and methods for intravascular intervention. 
       BACKGROUND 
       [0003]    People die from heart attacks. Heart attacks can be caused by the slow buildup of atherosclerotic plaque inside the blood vessels. The buildup of plaque occludes the flow of blood, and thus nutrients and oxygen, to a person&#39;s tissue and brain. Sometimes chunks of the atherosclerotic plaque break away and flow through the person&#39;s blood vessels. This can lead to serious and deadly strokes and heart attacks. If the plaque buildup is extensive enough, it will fully occlude the flow of blood, forming what is called a chronic total occlusion or CTO. If a CTO is not opened up, it can be fatal. 
         [0004]    One approach to treating a CTO is to insert an intravascular guidewire and use it to push across the CTO followed by a catheter. Unfortunately, guidewires and catheters are subject to a lot of friction. For example, where the guidewire extends through the patient&#39;s convoluted blood vessels within a catheter, at each bend, the catheter is curved, and the guidewire will typically be pushed against the wall of the catheter (i.e., the inside wall at the apex of the curve and the outside wall at the ends of the curve). The friction causes numerous problems. First, it is difficult to slide the guidewire to and through the CTO in a smooth deft motion because the friction interferes. Second, since the guidewire will not move until the friction is overcome, sometimes the guidewire resists motion and then moves forward suddenly. Unfortunately, crossing the CTO requires a lot of force but also precise control over that force. 
       SUMMARY 
       [0005]    The invention provides a catheter with a vibrating mechanism attached that gives a physician great control over an intravascular procedure by keeping the catheter in motion at times when the vibrating mechanism is active with the result that the physician need not overcome a coefficient of static friction. The physician is at all times faced with a substantially uniform coefficient of dynamic friction. This amount of friction quickly becomes familiar to the physician and in fact aids the physician in gently controlling the motion of the catheter in a smooth fashion. Since static friction is removed, the catheter or guidewire does not jump forward in fits and starts with a jerky and uncontrolled motion. Additionally, the motion of the catheter draws fluid along the surface of the guidewire (e.g., blood or exogenous contrast), lubricating the surface. Fluid is drawn into the catheter, where applicable. Where the guidewire lies against a vessel wall or the plaque of a CTO, fluid is drawn into that interface, lubricating it. The lubricated, vibrating guidewire thus is able to push through the CTO in a smooth, controlled motion. This gives a physician tools for crossing a CTO, opening up a patient&#39;s blood vessels. Also, by crossing the CTO with a guidewire, a physician can then use the guidewire to take the catheter across the CTO. The catheter can be used to deliver treatments, such as angioplasty balloons or stents. In this way, a catheter of the invention can be used to resolve life-threatening plaque buildup and avoid heart attacks. 
         [0006]    In certain aspects, the invention provides a method of intravascular intervention that includes inserting a catheter comprising an extended body into a lumen within tissue of a patient, advancing the catheter to a treatment site, vibrating a proximal end of the catheter with a mechanical vibrator, and treating the treatment site while a distal end of the catheter is vibrating. The mechanical vibrator may include a linear motor, a mass coupled to the motor by a spring, a pair of eccentric rotatable weights, a piezoelectric vibrator, an ultrasonic actuator, a non-resonant linear motor driving a mass, or a combination thereof. A distal portion of the catheter may optionally be given a low-friction surface treatment (e.g., such as a coating of PTFE on an exterior or interior surface of the catheter). In some embodiments, the method includes advancing the catheter over a guidewire to a chronic total occlusion. The catheter can be used to deliver a treatment such as a stent or balloon. 
         [0007]    In related aspects, the invention provides a device for intravascular intervention that includes a catheter member comprising an extended body with a proximal end and a distal end, a torquer fixed to the proximal end, and a mechanical vibrator coupled to the torque. The torque may include a pin vise. The device may include a guidewire within the catheter. The catheter can be used to deliver a treatment (e.g., with a balloon or a stent). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows a guidewire with catheter according to certain embodiments. 
           [0009]      FIG. 2  shows a reinforcement coil. 
           [0010]      FIG. 3  depicts a linear motor. 
           [0011]      FIG. 4  illustrates a catheter with a mechanical vibrator. 
           [0012]      FIG. 5  illustrates a catheter with mechanical vibrator with a spring. 
           [0013]      FIG. 6  shows use of a catheter and guidewire to approach an occlusion. 
           [0014]      FIG. 7  shows crossing an occlusion with a vibrating catheter. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The invention generally relates to catheters that vibrate. Systems and methods of the invention operate to decrease ambient friction around a guidewire and catheter via a vibration motion of the catheter. Additionally, the motion of the guidewire or catheter can aid in crossing a CTO. 
         [0016]      FIG. 1  shows an system  101  including a catheter  111  and a guidewire  109  according to certain embodiments of the invention. Catheter  111  includes a proximal portion  103  that is generally outside of a patient during use and a distal portion  105  configured for insertion into a patient. Guidewire  109  also includes a proximal portion and a distal portion  105 . Either catheter  111  or guidewire  109  includes at least one optical fiber for photoacoustic image as described herein. Proximal portion  103  may generally be said to define a housing area in that guidewires, endoscopes, or surgical implements may enter catheter  111  through proximal portion  103  and be housed, at least in part, within proximal portion  103 . 
         [0017]    Catheter  111  is capable of being delivered over a guidewire  109 . In some embodiments (not pictured in  FIG. 1 ), catheter  111  is an intravascular balloon catheters as is used for such procedures as balloon angioplasty, or percutaneous transluminal coronary angioplasty (PTCA). Catheter  111  generally has an elongate tubular shaft  111  with proximal portion  103  and distal portion  105 , and may include one or more passages or lumens. Use of pliable materials provides flexibility or maneuverability, allowing a catheter to be guided to a treatment site in a patient&#39;s blood vessels. Preferably, a catheter of the invention has enough stiffness to allow it to be pushed to a target treatment site, and accordingly, an ability to optimize a balance of pliability versus stiffness or pushability is beneficial to medical use. In certain embodiments, catheter  111  includes a stiffening wire or coil, or a reinforcement coil, to aid in transmitting the vibration form the proximal end to the distal end. Additionally, a shaft of the catheter can be provided that is capable of transmitting torque along an axis of the shaft. Devices for cardiovascular intervention are discussed in U.S. Pat. Nos. 6,830,559; 6,074,362; and U.S. Pat. No. 5,814,061, the contents of each of which are incorporated by reference. 
         [0018]    Catheter  111  could optionally include an angioplasty balloon  107  or other interventional device at distal portion  105  to expand or dilate blockages in blood vessels or to aid in the delivery of stents or other treatment devices. Blockages include the narrowing of the blood vessel called stenosis. 
         [0019]    Typically, a catheter  111  will include a guidewire lumen so that the catheter may be advanced along a guidewire. Guidewire lumen in a balloon catheter is described in U.S. Pat. No. 6,022,319 to Willard. Catheter  111  may include any suitable material such as, for example, nylon, low density polyethylene, polyurethane, or polyethylene terephthalate (PET), or a combination thereof (e.g., layers or composites). An inner surface of a guidewire lumen may include features such as a silicone resin or coating or a separate inner tube made, for example, of preformed polytetrafluoroethylene (PTFE). The PTFE tube may be installed within the catheter shaft by sliding it into place and then shrinking the catheter shaft around it. This inner PTFE sleeve provides good friction characteristics to the guidewire lumen, while the balance of the catheter shaft can provide other desired qualities. Other suitable materials for use in catheter  101  or an inner tube portion thereof include high density polyethylene (HDPE) or combinations of material, for example, bonded in multiple layers. 
         [0020]    Catheter  111  may include coaxial tubes defining separate inflation and guidewire lumens, for example, along a portion of, or an entirety of, a length of catheter  111 . A plurality of lumens may be provided in parallel configuration or coaxial at one point and parallel at another, with a twisting/plunging portion to affect a transition between the parallel segment and the coaxial segment (see., e.g., U.S. Pat. No. 7,044,964). Other possible configurations include one or more of a guidewire tube or guidewire lumen disposed outside of the balloon. Or the guidewire tube may be affixed to and extend along the wall of the balloon. In some embodiments, a proximal end of guidewire  109  is mounted in a torquer device. Any torquer device may be used. For example, a handle member may be fixed onto proximal end of guidewire  109  by welding, adhesives, clamps, or other suitable means. In some embodiments, the torque device comprises a pin vise. 
         [0021]      FIG. 2  shows a reinforcement coil  114  for transmitting vibration or torque along catheter  111 . Coil  114  is preferably a material that is more rigid than a remainder of a body of catheter  111 . Any suitable material may be used for coil  114  such as, for example, a plastic or polymer, a metal, or a nickel-titanium alloy or other allow. Coil  114  is depicted as a helix. Other embodiments, such as a woven mesh, are within the scope of the invention. In some embodiments, reinforcement is provided by substantially linear fibers extending along catheter  111 . Preferably, catheter  111  is coupled to a mechanical vibrator. Any suitable mechanical vibrator can be used. In some embodiments, catheter  111  is connected to a linear motor. 
         [0022]      FIG. 3  depicts a linear motor  117 . Linear motor  117  is an electric motor that has an unrolled stator and unrolled rotor  119  that produces a linear force along its length. One suitable mode of operation is as a Lorentz-type actuator, in which the applied force is linearly proportional to the current and the magnetic field (F=qv×B). One exemplary motor suitable for use as linear motor is the linear motor sold under the name Dover MAB-100 Linear Motor by Danaher Motion (Wood Dale, Ill.). 
         [0023]    Any vibratory motor can be used. For example, vibration can be induced by eccentric weight discs, piezoelectric material, linear or rotary motors, non-vibrator motors that operate against a non-uniform surface, or other means known in the art. Vibratory mechanical devices that can be modified for use with the invention are described in U.S. Pat. No. 8,336,643 to Harleman; U.S. Pat. No. 6,520,269 to Geiger; U.S. Pat. No. 5,780,958 to Strugach; and U.S. Pat. No. 4,819,740 to Warrington, the contents of which are incorporated by reference. 
         [0024]      FIG. 4  illustrates a catheter  111  with a mechanical vibrator provided by linear motor  117  connected to pin vise  113 . Operation of motor  117  imparts vibration to catheter  111 . The vibration is transmitted from a proximal portion of catheter  111  to a distal portion (e.g., the distal tip). This can be aided by coil  114 . 
         [0025]      FIG. 5  illustrates a catheter  111  with mechanical vibrator that includes a linear motor  117  fixed to catheter  111 , which drives a mass  202  connected via a spring  201  (partially disposed behind catheter  111  within motor  117  in the view shown in  FIG. 5 ). A resonant spring-mass system is beneficial in that it can accomplish good inertial vibration at low power. 
         [0026]    In some embodiments, a rotating motor drives a gear pair of eccentric rotating weights. This produces vibration in at least one direction. 
         [0027]    In certain embodiments, a non-resonant linear motor drives a mass to produce vibration. 
         [0028]    In some embodiments, vibration is provided by an ultrasonic actuator or transducer. This may be beneficial where high frequency vibration is desired and it provides a minimum displacement of guidewire  109 . 
         [0029]      FIGS. 6-7  show use of guidewire  109  for crossing occlusion  152  (e.g., an atherosclerotic plaque) in a blood vessel treatment site  151 . As distal portion  105  of guidewire  109  approaches treatment site  151  (such as a region of a blood vessel affected by atherosclerotic plaque), a physician can optionally view site  151  on a monitor of an associated medical imaging instrument (not pictured). Using mechanical vibrator  117 , a distal portion of catheter  111  is vibrated, as shown in  FIG. 7 . This keeps catheter  111  in motion at times when the vibrating mechanism is active with the result that the physician need not overcome a coefficient of static friction. The physician is at all times faced with a substantially uniform coefficient of dynamic friction. This amount of friction quickly becomes familiar to the physician and in fact aids the physician in gently controlling the motion of the guidewire in a smooth fashion. Since static friction is removed, guidewire  109  does not jump forward in fits and starts with a jerky and uncontrolled motion. Additionally, the motion of catheter  111  draws fluid along the surface of the guidewire (e.g., blood or exogenous contrast), lubricating the surface. The lubricated, vibrating guidewire  109  thus is able to push through the occlusion  152  in a smooth, controlled motion. This gives a physician tools for crossing occlusion  152 . Guidewire  109  can be used to deliver a catheter carrying treatments, such as angioplasty balloons or stents. Intravascular procedures are described in U.S. Pat. No. 8,361,097 to Patel; U.S. Pat. No. 8,298,149 to Hastings; and U.S. Pat. No. 5,713,848 to Dubrul, the contents of each of which are incorporated by reference. 
         [0030]    Such vascular intervention procedures by catheter are often performed in specialized clinical environments known as cath labs. The catheterized intervention procedures described herein may be performed with associated imaging procedures (e.g., using IVUS and OCT instruments). Exemplary IVUS methods are discussed in U.S. Pat. No. 8,289,284; U.S. Pat. No. 7,773,792; U.S. Pub. 2012/0271170; U.S. Pub. 2012/0265077; U.S. Pub. 2012/0226153; and U.S. Pub. 2012/0220865. OCT systems and methods are described in U.S. Pub. 2011/0152771; U.S. Pub. 2010/0220334; U.S. Pub. 2009/0043191; U.S. Pub. 2008/0291463; and U.S. Pub. 2008/0180683, the contents of each of which are hereby incorporated by reference in their entirety. 
         [0031]    In some embodiments, guidewire  109  is used to deliver, through the use of catheter  111 , an angioplasty balloon. Generally, a balloon will include a flexible, inelastic material designed to expand. By this type of expansion, a balloon may impose pressures of several atmospheres to expand the stenosis or may be used to deploy a stent. After the balloon has been expanded, it is then deflated and removed from the patient, allowing improved blood flow through the vessel. Suitable materials may include polyvinyl chloride (PVC), nylon, polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and copolyesters, polyether-polyester block copolymers, polyamides, polyurethane, poly(ether-block-amide) and the like. Balloons are described in U.S. Pat. No. 7,004,963; U.S. Pub. 2012/0071823; U.S. Pat. No. 5,820,594; and U.S. Pub. 2008/0124495, the contents of each of which are incorporated by reference. Balloon catheters are described in U.S. Pat. No. 5,779,731 and U.S. Pat. No. 5,411,016, incorporated by reference. 
         [0032]    In some embodiments, the balloon includes artificial muscle (electro-active polymer). Electro-active polymers exhibit an ability to change dimension in response to electric stimulation. The change may be driven by electric field E or by ions. Exemplary polymers that respond to electric fields include ferroelectric polymers (commonly known polyvinylidene fluoride and nylon 11, for example), dielectric EAPs, electro-restrictive polymers such as the electro-restrictive graft elastomers and electro-viscoelastic elastomers, and liquid crystal elastomer composite materials. Ion responsive polymers include ionic polymer gels, ionomeric polymer-metal composites, conductive polymers and carbon nanotube composites. Common polymer materials such as polyethylene, polystyrene, polypropylene, etc., can be made conductive by including conductive fillers to the polymer to create current-carrying paths. Many such polymers are thermoplastic, but thermosetting materials such as epoxies, may also be employed. Suitable conductive fillers include metals and carbon, e.g., in the form of sputter coatings. Electro-active polymers are discussed in U.S. Pat. No. 7,951,186; U.S. Pat. No. 7,777,399; and U.S. Pub. 2007/0247033, the contents of each of which are incorporated by reference. 
         [0033]    In some embodiments, guidewire  109  is used to deliver, through the use of catheter  111 , a stent. Any suitable stent may be used with device  101 . One exemplary device for stent is the Palmaz-Schatz stent, described, for example, in U.S. Pat. No. 4,733,665. Suitable stents are described in U.S. Pat. No. 7,491,226; U.S. Pat. No. 5,405,377; U.S. Pat. No. 5,397,355; and U.S. Pub. 2012/0136427, the contents of each of which are expressly incorporated herein by reference. Generally, a stent has a tubular body including a number of intersecting elongate struts. The struts may intersect one another along the tubular body. In a non-deployed state, the tubular body has a first diameter that allows for delivery of the stent into a lumen of a body passageway. When deployed, the stent has a second diameter and deployment of the stent causes it to exert a radially expansive force on the lumen wall. Methods of using stents are discussed in U.S. Pat. No. 6,074,362; U.S. Pat. No. 5,158,548; and U.S. Pat. No. 5,257,974, the contents of each of which are incorporated by reference. In some embodiments, stent  161  includes a shape-retaining or shape memory material such as nitinol and is self-expanding and thermally activatable within a vessel upon release. Such devices may automatically expand to a second, expanded diameter upon being released from a restraint. See, e.g., U.S. Pat. No. 5,224,953, the contents of which are incorporated herein by reference. 
       INCORPORATION BY REFERENCE 
       [0034]    References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes. 
       EQUIVALENTS 
       [0035]    Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.