Patent ID: 12232754

DETAILED DESCRIPTION

Described herein are devices, systems, and methods for generating shock waves that propagate in a substantially forward direction to treat vascular diseases, such as chronic total occlusion (CTO) or circumferential calcium, or to treat urinary diseases, such as concretions or kidney stones in the ureter. In accordance with the present disclosure, a shock wave device includes an outer covering and an inner member forming a guide wire lumen. The outer covering and inner member are connected at a distal end of the device. A first conductive wire and a second conductive wire extend along the length of the device within the volume between the outer covering and the inner member, and end proximate to the distal end of the device. A conductive emitter band circumscribes the ends of the first and second wires to form a first spark gap between the end of the first wire and the emitter band and a second spark gap between the end of the second wire and the emitter band.

When the volume is filled with conductive fluid (e.g., saline and/or imaging contrast agent) and a high voltage pulse is applied across the first and second wires, first and second shock waves can be initiated from the first and second spark gaps. The voltage may range from 100 to 10,000 volts for various pulse durations. This high voltage may generate a gas bubble at the end surface of a wire and cause a plasma arc of electric current to traverse the bubble to the emitter band and create a rapidly expanding and collapsing bubble, which in turn creates a mechanical shock wave at the distal end of the device. The positioning of the emitter band in relation to the end of the wire may result in the shock wave propagating out in a substantially forward direction toward the distal end of the device. The shock waves may be mechanically conducted through the conductive fluid and through the outer covering in the substantially forward direction to apply mechanical force or pressure to impinge on an occlusion or calcium facing the distal end of the device. The size, rate of expansion and collapse of the bubble (and therefore, the magnitude, duration, and distribution of the mechanical force) may vary based on the magnitude and duration of the voltage pulse, as well as the distance between the end of the wire and the emitter band. The emitter band may be made of materials that can withstand high voltage levels and intense mechanical forces (e.g., about 1000-2000 psi or 68-136 ATM in a few microseconds) that are generated during use. For example, the emitter band may be made of stainless steel, tungsten, nickel, iron, steel, and the like.

FIG.1depicts a cutaway perspective view of an example shock wave device100for generating forward directed shock waves, in accordance with some embodiments. The device100includes an outer covering102(e.g., a flexible outer tube) and an inner member104that forms a lumen for a guide wire114. The outer covering102and inner member104are connected at a distal end of the device100, where the guide wire114may exit the device100. The interior volume of the device100between the outer covering102and inner member104may be filled with a conductive fluid (e.g., saline and/or imaging contrast agent). Two insulated conductive wires106(e.g., insulated copper wires) extend along the length of the device100within the interior volume. While only one wire106is visible inFIG.1, the second wire106extends along an opposing side of the inner member104, as shown inFIGS.2-3. The two wires106end near the distal end of the device100where the guide wire exits the lumen formed by the inner member104. The ends of the two wires106include uninsulated portions (not shown). For example, the flat circular surfaces at the ends of the two wires may be uninsulated. An emitter band108is positioned within the interior volume around the ends of the two wires106. The emitter band108may be a conductive cylinder with a diameter larger than the total diameter of the inner member104and the two wires106combined, such that the emitter band circumscribes the ends of the two wires106without contacting the wires, as shown inFIG.2. An insulating sheath110(e.g., a polyimide insulator) may be positioned around the inner member104to separate the two wires106from the inner member104and to further insulate the two wires106from one another. In this way, the preferred conductive path between the two wires106is through the emitter band108. When a high voltage pulse is applied across the two wires106, an electrical current will arc from the uninsulated end of one wire to the emitter band108, and then arc again from the emitter band108to the uninsulated end of the other wire. As a result, shock waves are initiated at the distal end of the shock wave device100, which then propagate through the conductive fluid and the wall of the outer covering102to impinge on an occlusion or calcification.

In some embodiments, the device100may include a second pair of wires (not shown) offset from wires106by 90 degrees. For example, if wires106are positioned at 0 and 180 degrees, the second pair of wires may be positioned at 90 and 270 degrees. The second pair of wires also end near the distal end of the device100and include uninsulated portions at their ends. The emitter band108circumscribes the ends of the second pair of wires as well. A separate high voltage pulse may be applied across the second pair of wires to generate a second pair of arcs with the emitter band108. As a result, a second set of shock waves are initiated from the distal end of the device100. The first pair of wires106and the second pair of wires may be activated alternately, which may improve the effectiveness of the device100by further spreading the shock waves.

A fluid return line112with an inlet near the distal end of the device100draws in the conductive fluid from the interior volume, while a fluid pump (not shown) pumps in additional conductive fluid via a fluid inlet (shown inFIG.5) at a proximal end of the device100. In this way, the fluid return line112and fluid pump circulate the conductive fluid under pressure within the interior volume. Circulation of the conductive fluid may prevent bubbles created by the device100from becoming trapped within the distal tip of the device100due to the limited space within the tip. Furthermore, circulation of the conductive fluid may aid in cooling the device100and treatment site.

FIG.2depicts a side sectional view of an example shock wave device100for generating forward directed shock waves, in accordance with some embodiments. As shown inFIG.2, the two conductive wires106(e.g., polyimide-insulated copper wires) are positioned along opposing sides of the inner member104. Each of the wires106include uninsulated wire ends202. The insulating sheath110(e.g., polyimide tubing) is positioned in a region proximate to the uninsulated wire ends202to decrease the likelihood of electrical current arcing from one wire end to the other. The emitter band108is positioned with a forward edge closer to the distal end of the device100than the wire ends202, such that two spark gaps are formed between each of the wire ends202and the emitter band108. The positioning of the wire ends202, insulating sheath110, and emitter band108makes it so that when a high voltage pulse is applied across the two wires106, an electrical current will arc from the uninsulated end of one wire to the emitter band108, and then arc again from the emitter band108to the uninsulated end of the other wire. As a result, shock waves are initiated at the distal end of the shock wave device100, which then propagate through the conductive fluid and the wall of the outer covering102to impinge on an occlusion or calcification. The positioning of the emitter band108closer to the distal end of the device than the wire ends202helps to encourage the shock waves to propagate in a substantially forward direction (e.g., longitudinally out of the distal end of the device100). Shock waves may be generated repeatedly, as may be desirable by the practitioner to treat a region of vasculature.

FIG.3depicts a front sectional view of an example shock wave device100for generating forward directed shock waves, in accordance with some embodiments. As shown inFIG.3, the emitter band108circumscribes the two conductive wires106(e.g., insulated copper wires) and the fluid return line112. The fluid return line112includes an inlet that draws in conductive fluid from the interior volume of the device to allow the conductive fluid to be circulated within the distal end of the device100.

FIG.4depicts an extended side sectional view of an example shock wave device100for generating forward directed shock waves, in accordance with some embodiments. As shown inFIG.4, in some embodiments, the outer covering of the device100includes an angioplasty balloon402. The balloon402may be inflated by pumping additional fluid into the interior volume of the device. The balloon402may be inflated before or after applying shock waves to a treatment region. For example, in some embodiments, after forward directed shock waves are initiated using the emitter band108at the distal end of the device100to break apart an occlusion, the device100is advanced further into a patient's vascular, and the balloon402is inflated in the region of the occlusion to further treat the region.

In some embodiments, the shock wave device100may include secondary emitter bands404located in a medial location of the device100. The device100shown inFIG.4includes two secondary emitter bands404, but various numbers of secondary bands404may be used. For example, in some embodiments, the device100may include a single secondary emitter band404. In other embodiments, the device100may include five or more secondary emitter bands404. The secondary emitter bands404may generate shock waves using a variety of techniques. For example, the secondary emitter bands404may generate shock waves using low-profile or coplanar electrodes, such as those described in U.S. Pat. No. 8,888,788 and U.S. application Ser. No. 15/346,132, which are hereby incorporated by reference in their entireties. The shock waves may radiate in a substantially radial direction from the medial location of the secondary emitter bands404. In some embodiments, the secondary emitter bands404may initiate shock waves independently of the emitter band108at the distal end of the device100. For example, in some embodiments, after forward directed shock waves are initiated using the emitter band108at the distal end of the device100to break apart an occlusion, the device100is advanced further into a patient's vascular until the medial location of a secondary emitter band404is aligned with the region of the occlusion. Then additional shock waves may be initiated from the secondary emitter band404to further treat the region. In order to permit independent operation, additional conductive wires may be provided between the high voltage source and the second emitter bands404.

In some embodiments, forward directed shock waves from the emitter band108, radial directed shock waves from the secondary emitter bands404, and inflation of the angioplasty balloon402may be utilized in various sequences and combinations to treat plaques or obstructions in vessels. The vessels may include blood vessels in a patient's vascular system or ureters in the patient's urinary system.

FIG.5depicts a side view of an extended length of an example shock wave device100, in accordance with some embodiments. The shock wave device100may be in communication with a fluid source and fluid pump (not shown) that introduces conductive fluid into an interior volume of the device100via a fluid inlet502. The fluid pump may fill the interior volume with fluid to a certain pressure. The conductive fluid may be circulated within the interior volume of the device100by drawing fluid into the fluid return line shown inFIGS.1and3, and then dispelling it through a waste outlet504. The waste outlet504may include a pressure relief valve to maintain the fluid pressure within the interior volume of the device while the conductive fluid is circulated. Circulation of the conductive fluid may prevent bubbles created by the device100from becoming trapped within the distal tip of the device100due to the limited space within the tip. Trapped bubbles may block subsequent shock waves from propagating from the device100, thus it is beneficial to prevent their build-up. In some embodiments, the waste outlet504may be connected to the fluid source so that the fluid pump recirculates the waste fluid.

FIG.6is a flowchart representation of an exemplary method for generating forward directed shock waves. As depicted inFIG.6, a shock wave device is introduced into a vessel (602). The vessel may include blood vessels in a patient's vascular system or ureters in the patient's urinary system. The shock wave device may be the device100described in reference toFIGS.1-5. The shock wave device is advanced within the vessel such that a distal end of the device faces a first treatment region (604). The first treatment region may include a chronic total occlusion (CTO), circumferential calcium, a kidney stone, or other obstructions or concretions. Once the distal end of the shock wave device is facing the first treatment region, a high voltage pulse is applied across first and second wires to initiate first and second shock waves from first and second spark gaps formed between the first and second wires and an emitter band (606). Due to the positioning of the first and second wires and the emitter band, the first and second shock waves propagate in a substantially forward direction out of the shock wave device to impinge on the occlusion or calcium in the first treatment area. In some embodiments, the shock wave device may then be advanced further within the vessel such that an angioplasty balloon is aligned with the first treatment region or with a second treatment region (608). The angioplasty balloon may then be inflated in the first or second treatment regions (610). In this way, conventional angioplasty balloon treatments may be applied to treat one or more treatment regions after the shock wave treatments are applied. Alternatively or in addition, in some embodiments, the shock wave device may be advanced further within the vessel such that a secondary emitter band at a medial location of the device is aligned with the first treatment region or with a second treatment region (612). Third shock waves may then be initiated from the secondary emitter band to apply additional shock wave treatment to the first or second treatment areas (614). Steps604-614may be carried out in various sequences or combinations, and repeated as necessary, when appropriate to treat the patient.

While this invention has been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention. For all of the embodiments described above, the steps of the methods need not be performed sequentially.