EP4017573A1 - Rotateable dilator and delivery systems - Google Patents

Abstract

A delivery system comprises a sheath having an outer tube surrounding a hollow interior and a dilator configured to fit at least partially into the hollow interior of the sheath. The dilator comprises a distal portion configured to at least partially dilate a blood vessel, a middle portion, a proximal portion, and an inner lumen extending through the distal portion, middle portion, and the proximal portion.

Description

ROTATEABLE DILATOR AND DELIVERY SYSTEMS

RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application No. 62/890,533, filed on August 22, 2019, entitled ROTATEABLE DILATOR AND DELIVERY SYSTEMS, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

[0002] The present disclosure generally relates to the field of delivering medical implant devices and/or therapies.

[0003] Transcatheter delivery of implant devices and/or therapies to the heart can be performed to address various heart abnormalities. Delivery of implant devices and/or therapies to the heart can be performed for treatment of various conditions, such as elevated pressure in the left atrium.

SUMMARY

[0004] For purposes of summarizing the disclosure, certain aspects, advantages and novel features have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, the disclosed embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0005] Some implementations of the present disclosure relate to a delivery system comprising a sheath having an outer tube surrounding a hollow interior and a dilator configured to fit at least partially into the hollow interior of the sheath. The dilator comprises a distal portion configured to at least partially dilate a blood vessel, a middle portion, a proximal portion, and an inner lumen extending through the distal portion, middle portion, and the proximal portion.

[0006] The dilator may have a cylindrical shape around the inner lumen. In some embodiments, the distal portion has an at least partially tapered surface. The middle portion may be situated between the distal portion and the proximal portion.

[0007] In some embodiments, the middle portion has a maximal diameter of the dilator. A diameter at the proximal portion may be less than a maximal diameter of the dilator. [0008] In some embodiments, there is at least one gap between the dilator and the sheath when the dilator is situated within the hollow interior of the sheath.

[0009] The at least one gap may be between the proximal portion and the sheath. In some embodiments, the proximal portion is configured not to contact the sheath. There may be no gap between the middle portion and the sheath. In some embodiments, the inner lumen of the dilator is configured to fit a puncture needle.

[0010] The dilator may be configured to twist while situated at least partially within the hollow interior of the sheath.

[0011] In some embodiments, twisting the dilator may be configured to cause twisting of a puncture needle within the inner lumen of the dilator. The dilator may be configured to tilt while situated at least partially within the hollow interior of the sheath.

[0012] Some implementations of the present disclosure relate to a dilator configured to fit at least partially into the hollow interior of a sheath. The dilator comprises a distal portion configured to at least partially dilate a blood vessel, a middle portion, a proximal portion, and an inner lumen extending through the distal portion, middle portion, and the proximal portion.

[0013] In some embodiments, the middle portion has a cylindrical shape around the inner lumen. The distal portion may have an at least partially tapered surface.

[0014] In some embodiments, the middle portion is situated between the distal portion and the proximal portion. The middle portion may have a maximal diameter of the dilator.

[0015] In some embodiments, a diameter at the proximal portion is less than a maximal diameter of the dilator. The proximal portion may be configured to form at least one gap between the proximal portion and the sheath.

[0016] In some embodiments, the proximal portion is configured not to contact the sheath.

[0017] The middle portion may be configured to form a gapless contact with the sheath. In some embodiments, the inner lumen is configured to fit a puncture needle.

[0018] The distal portion may be configured to twist while situated at least partially within the sheath. In some embodiments, twisting the distal portion is configured to cause twisting of a puncture needle within the inner lumen at the distal portion. The distal portion may be configured to tilt while situated at least partially within the sheath.

[0019] Some implementations of the present disclosure relate to a method comprising introducing a sheath and a dilator into a blood vessel. The dilator is situated at least partially within the sheath and the dilator comprises an inner lumen. The method further comprises inserting a needle through the inner lumen of the dilator, twisting the dilator to cause twisting of the needle to a desired position, and advancing the needle out of a distal end of the dilator.

[0020] In some embodiments, there is at least one gap between the dilator and an inner surface of the sheath. At least a portion of the dilator may form a gapless contact with the sheath.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various embodiments are depicted in the accompanying drawings for illustrative purposes and should in no way be interpreted as limiting the scope of the inventions. In addition, various features of different disclosed embodiments can be combined to form additional embodiments, which are part of this disclosure. Throughout the drawings, reference numbers may be reused to indicate correspondence between reference elements. However, it should be understood that the use of similar reference numbers in connection with multiple drawings does not necessarily imply similarity between respective embodiments associated therewith. Furthermore, it should be understood that the features of the respective drawings are not necessarily drawn to scale, and the illustrated sizes thereof are presented for the purpose of illustration of inventive aspects thereof. Generally, certain of the illustrated features may be relatively smaller than as illustrated in some embodiments or configurations.

[0022] Figure 1 is a cross-sectional view of a human heart.

[0023] Figure 2 is a side view of an example delivery system including a sheath and a dilating end positioned within a blood vessel of a human body in accordance with some embodiments.

[0024] Figure 3 provides a cross-sectional view of a steerable sheath in accordance with some embodiments.

[0025] Figure 4 provides a cross-sectional view of an example dilator in accordance with some embodiments.

[0026] Figures 5A-5D illustrate delivery systems including sheaths and dilators in accordance with some embodiments.

[0027] Figures 6A and 6B illustrate an example needle delivery process for a delivery system including a dilator, sheath, and/or a needle in accordance with some embodiments. [0028] Figure 7 is a flow diagram of a process for deploying a delivery system including a dilator and a sheath into and/or through a blood vessel in accordance with some embodiments.

DETAILED DESCRIPTION

[0029] The headings provided herein are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.

[0030] Various features of a heart 1 are described with reference to Figure 1 to assist in understanding the present disclosure. The heart 1 includes four chambers, namely the left atrium 2, the left ventricle 3, the right ventricle 4, and the right atrium 5. A wall of muscle, referred to as the septum 17, separates the left atrium 2 and right atrium 5, and the left ventricle 3 and right ventricle 4. Blood flow through the heart 1 is at least partially controlled by four valves, the mitral valve 6, aortic valve 7, tricuspid valve 8, and pulmonary valve 9. The mitral valve 6 separates the left atrium 2 and the left ventricle 3 and controls blood flow therebetween. The aortic valve 7 separates and controls blood flow between the left ventricle 3 and the aorta 12. The tricuspid valve 8 separates the right atrium 5 and the right ventricle 4 and controls blood flow therebetween. The pulmonary valve 9 separates the right ventricle 4 and the pulmonary artery 11, controlling blood flow therebetween.

[0031] In a healthy heart, the heart valves can properly open and close in response to a pressure gradient present during various stages of the cardiac cycle (e.g., relaxation and contraction) to at least partially control the flow of blood to a respective region of the heart and/or to blood vessels. Deoxygenated blood arriving from the rest of the body generally flows into the right side of the heart for transport to the lungs, and oxygenated blood from the lungs generally flows into the left side of the heart for transport to the rest of the body.

During ventricular diastole, deoxygenated blood arrive in the right atrium 5 from the inferior vena cava 18 and superior vena cava 19 to flow into the right ventricle 4, and oxygenated blood arrive in the left atrium 2 from the pulmonary veins to flow into the left ventricle 3. During ventricular systole, deoxygenated blood from the right ventricle 4 can flow into the pulmonary artery 11 for transport to the lungs (e.g., via the left and right pulmonary arteries), and oxygenated blood can flow from the left ventricle 3 to the aorta 12 for transport to the rest of the body.

[0032] A number of conditions can contribute to a higher than normal pressure in the left atrium 2. Dysfunction of the mitral valve 6 can contribute to elevated left atrial pressure. Conditions such as mitral valve regurgitation and/or stenosis may result in difficulty in pumping blood from the left atrium 2 to the left ventricle 3, contributing to elevated pressure in the left atrium 2. Valve stenosis can cause a valve to become narrowed or obstructed. Mitral valve stenosis can restrict blood flow from the left atrium 2 to the left ventricle 3. Valve regurgitation occurs when a valve does not close properly. For example, regurgitation can occur due to improper coaptation of the valve leaflets. Mitral valve regurgitation can result in blood flow leakage back into the left atrium 2 from the left ventricle 3 when the left ventricle 3 contracts. Restricted flow of blood from the left atrium 2 into the left ventricle 3, and blood flow leakage from the left ventricle 3 back into the left atrium 2 can both contribute to elevated atrial pressure. Dysfunction in the left ventricle 3 can also contribute to elevated left atrial pressure. Elevated left atrial pressure may lead to left atrial enlargement, producing symptoms such as shortness of breath during exertion, fatigue, chest pain, fainting, abnormal heartbeat, and swelling of the legs and feet.

[0033] Various medical procedures for treatment and/or prevention of various heart conditions involve use of steerable sheath/catheter systems. A steerable sheath can be used to facilitate introduction of various medical devices into the human body. For example, steerable sheaths can be used in cardiopulmonary bypass procedures such as minimal incision aortic valve replacement procedures, mitral valve repair or replacement procedures, tricuspid valve procedures, re-operations, intracardiac myxoma resection, patent foramen ovale repairs, atrial septal defect repairs, and ablative maze procedures for atrial fibrillation. Steerable sheaths may utilize one or more dilators and/or steerable sheath tips allowing for improved insertion and/or navigation through the coronary sinus. In some cases, dilators may have at least partially tapered surfaces that may provide for effective tracking and/or pre-dilation of vessels.

[0034] Figure 2 is a side view of an example delivery system 200 including a sheath 201 and a dilating end 202 positioned within a blood vessel 205 (e.g., the coronary sinus) of a human body. A cross-sectional view of the blood vessel 205 is shown. The sheath 201 and dilating end 202 may be separate devices and/or may comprise a single device. For example, the dilating end 202 may extend from the sheath 201. However, the dilating end 202 may alternatively be a separate device from the sheath 201. In some embodiments, the dilating end 202 may have a tapered and/or conical shape to gradually dilate at least some portions of the blood vessel 205. For example, some portions of the blood vessel 205 may have a smaller diameter than some portions of the delivery system 200. Accordingly, the dilating end 202 may enter the blood vessel 205 first and as the delivery system 200 moves through the blood vessel 205, the surface of the dilating end 202 may contact inner walls of the blood vessel 205 and press and/or expand the blood vessel 205 outward to accommodate the delivery system 200.

[0035] The delivery system 200 may be at least partially removed from the body after delivery. For example, in cases in which the dilating end 202 is separate from the sheath 201, the dilating end 202 may be removed from the body after delivery. This is because the purpose of the dilating end 202 may be to dilate the blood vessel 205 to allow the sheath 201 to fit within the blood vessel 205. Once the sheath 201 is situated at a desired position within the blood vessel 205, the dilating end 202 may not serve any purpose and/or may obstruct other operations, including delivery of needles and/or other devices through the sheath 201.

[0036] Some embodiments described herein provide improved sheaths, dilators, and/or and other delivery devices and/or improved methods for steering and/or otherwise delivering sheaths and/or other instruments into and/or through vessels of the human body. The terms “dilator,” “dilating end,” and/or “means for dilating” are used herein according to their broad and ordinary meaning and may refer to any device and/or set of devices configured to dilate and/or pre-dilate a blood vessel and/or otherwise facilitate insertion and/or navigation of a sheath into and/or through a human body. Similarly, the terms “sheath,” “catheter,” and/or “steerable sheath” are used herein according to their plain and ordinary meanings and can refer or apply generally to any type of elongate and/or tubular delivery devices, which may include sheaths, catheters, tubes, cannulas, and/or shafts (e.g., inner/outer shafts). A sheath may comprise an inner lumen configured to slidably receive instrumentation, such as for placement within an atrium and/or coronary sinus.

[0037] A dilator as described herein may have an at least partially tapered (e.g., cone-shaped) surface at least at or near a distal end/portion of the dilator. The dilator may be introduced into a blood vessel to stretch the vessel and create a sufficiently- sized opening for a sheath (e.g., a steerable sheath) or various other devices. The dilator may be configured to fit at least partially inside a sheath and/or at least a portion of the dilator may be configured to protrude from a distal end of the sheath. For example, a tapered end of the dilator may be configured to at least partially protrude from the sheath. The dilator and sheath may be configured to be introduced together to access the inferior vena cava, ostium, coronary sinus, and/or other vessels and/or chambers of the human body. In some cases, the dilator may have an inner lumen configured to receive various instruments. Accordingly, the dilator may be retained within the body post-delivery to provide a port through which a variety of needles, catheters, guidewires, and/or other devices may be inserted. [0038] Some embodiments described herein provide steerable sheaths and/or dilators which may be used to facilitate delivery of various devices, including for example shunt needles. In some embodiments, a dilator may be configured to serve as a conduit for delivering shunt needles and similar devices. For example, a dilator may have an inner lumen configured to receive various instruments. Accordingly, the dilator may not be removed following delivery of the dilator and/or steerable sheath but may be configured for use post delivery.

[0039] In some cases, at least a portion of a dilator may be configured to fit tightly into a lumen of a sheath. For example, when the dilator is situated within a lumen of the sheath, there may be no gaps (e.g., gapless contact) and/or minimal gaps between at least a portion (e.g., a middle portion) of an outer surface of the dilator and an inner surface of the sheath. The gapless portion of the dilator may have an approximately cylindrical shape to conform to a cylindrical inner surface of the sheath. The surface of the gapless (e.g., middle) portion of the dilator may be generally solid and/or smooth without dimples, grooves, and/or other features which may form gaps between the dilator and sheath. However, if the entire dilator is configured to fit tightly and/or gaplessly within a lumen of a sheath, it may be difficult to rotate, torque, and/or otherwise adjust the dilator while it is situated at least partially within the sheath. For example, contact between an outer surface of the dilator and an inner surface of the sheath may cause excessive friction when the dilator is twisted or otherwise adjusted, thereby making it difficult for surgeons to navigate the dilator and/or sheath.

[0040] Steerable sheaths and/or dilators described herein may be configured to reduce surface contact between the steerable sheaths and dilators. For example, at least a portion of a dilator may have a diameter that is sufficiently lower than an inner diameter of a sheath such that when the dilator is situated within an inner lumen of the sheath, there may be at least one gap between at least a portion of the dilator and sheath on one or more sides of the dilator and/or sheath. Moreover, at least a portion of the dilator may not be in contact with the sheath while the dilator is situated within the sheath. In this way, friction may be reduced and/or minimized when the dilator and/or sheath is twisted or otherwise adjusted and surgeons can more easily and/or effectively control the sheath and/or dilator.

[0041] The devices and/or methods described herein may provide several advantages. In some embodiments, a dilator may have multiple functions. For example, a dilator may be utilized as a system access tool and/or as an instrument (e.g., guidewire and/or needle) delivery device. Use of the dilator as a system access tool may reduce a number of devices which may be required to be introduced to the body. Moreover, a sheath may be configured to have a much smaller profile because an additional access tool may not be required to be pass through the sheath. At least one catheterization step may be eliminated due at least in part to the multiple functions of the dilator. Furthermore, unlike some conventional sheath and/or dilator designs in which there may be a tight fit between the sheath and dilator, some dilators described herein may be capable of being moved freely within a sheath due to reduced surface contact between the dilator and an inner surface of the sheath.

[0042] Figure 3 provides a cross-sectional view of a steerable sheath 300 in accordance with some embodiments. The sheath 300 may be an elongate device having an outer tube 301 and/or an inner lumen 302, which may comprise a generally hollow area/interior surrounded at least partially or completely along at least one axis (e.g., a lateral cross-section) by the outer tube 301. In some embodiments, the inner lumen 302 may have a generally tubular (e.g., cylindrical) form. The outer tube 301 may have a cylindrical/tubular or other shape and/or may be shaped and/or sized to fit through a blood vessel of a human body. In some embodiments, the outer tube 301 may be at least partially flexible to allow the sheath 300 to bend. The outer tube 301 may comprise an inner surface 301a and/or an outer surface 301b. The inner surface 301a may be configured to be exposed the inner lumen 302 of the sheath 300 and the outer surface 301b may be configured to be exposed to a blood vessel and/or other area or chamber of the human body in which the sheath 300 may be placed. The outer tube 301 may have any thickness (i.e., distance between the inner surface 301a and the outer surface 301b). In some embodiments, the outer tube 301 may have a constant and/or uniform thickness at every point of the outer tube 301. However, the outer tube 301 may have variable thicknesses.

[0043] The inner lumen 302 may be a cavity and/or at least partially empty space passing through the outer tube 301 of the sheath 300. In some embodiments, the inner lumen 302 may extend from a distal end 305 of the sheath to a proximal end of the sheath 300. The distal end 305 of the sheath 300 may comprise an opening into the sheath and/or into the inner lumen 302 of the sheath 300 (e.g., the vertical line illustrated at the distal end 305 may represent the outer tube 301. The inner lumen 302 may have a first diameter 306 representing a distance between opposite/opposing portions of the inner surface 301a. The inner lumen 302 may have a constant diameter along the entire length of the outer tube 301 (e.g., the first diameter 306 may be the diameter of the inner lumen 302 at any point of the inner lumen 302) and/or the inner lumen 302 may have varying diameters. In some embodiments, the outer tube 301 may comprise a tapered section 312 at or near the distal end 305 of the sheath 300. The tapered section 312 may represent a portion of the outer tube 301 at which the thickness of the outer tube 301 is less than a maximal thickness of the outer tube 301. In some embodiments, the tapered section 312 may represent a gradual reduction and/or increase of thickness of the outer tube 301. The slope of the tapered section 312 may match a slope of a dilator which may be used in conjunction with the sheath 300. However, in some cases, a dilator may be utilized separately from the sheath 300 and/or without use of a sheath 300.

[0044] In some embodiments, the sheath 300 may be configured to receive a pull wire 308 or similar device. The pull wire 308 may comprise a wire or similar device and/or may be configured to be situated at least partially within the outer tube 301 of the sheath 300. The pull wire 308 may be configured to assist a surgeon in steering and/or otherwise controlling the sheath 300. For example, when the pull wire 308 is tensioned and/or pulled, the distal end 305 of the sheath 300 may be flexed and/or steered. In some embodiments, the pull wire 308 may be configured to attach to, weld to, contact, and/or extend from a pull ring 310 or similar device. The pull wire 308 and/or pull ring 310 may be configured to be situated within the outer tube 301 (e.g., between the inner surface 301a and outer surface 301b) and/or within the inner lumen 302. In some embodiments, the pull wire 308 may be attached via welding and/or other methods to the pull ring 310. An actuator and/or similar device may be used to steer the sheath 300.

[0045] In some embodiments, the outer tube 301 may have a generally constant thickness (i.e., distance between the inner surface 301a and the outer surface 301b) across an entire length (e.g., from the distal end 305 to a proximal end) of the outer tube 301. However, the outer tube 301 may have varying thickness. For example, at least some portions of the inner surface 301a may be configured to have a wavy and/or otherwise indented structure such that at least some portions of the outer tube 301 may have a smaller thickness than a maximal thickness of the outer tube 301. Accordingly, the inner lumen 302 of the sheath 300 may have varying diameters. For example, the diameter of the inner lumen 302 may increase at points of the sheath 300 at which the outer tube 301 has a reduced thickness. Additionally or alternatively, a diameter of the outer tube 301 may decrease at points of the sheath 300 at which the outer tube 301 has a reduced thickness. For example, the inner surface 301a of the outer tube 301 may have a generally flat shape and the outer surface 301b of the outer tube 301 may have a wavy, jagged, bumpy, indented, and/or otherwise at least partially non-flat shape. [0046] Because Figure 3 provides a cross-sectional view of the sheath 300, various components of the sheath 300 are shown in a common plane. Various components of the sheath 300 may have a three-dimensional form, which will be understood by those having skill in the art. For example, the outer tube 301 may have a cylindrical/tubular form. Similarly, the pull ring 310 may have an elliptical (e.g., circular) form and/or may be configured to be situated within and/or against a full elliptical portion of the outer tube 301. For example, the pull ring 310 may be situated within the outer tube 301 and may form a continuous ellipse around the inner lumen 302. The inner lumen 302 may represent a cylindrical or similar space within the sheath 300. In some embodiments, a size and/or shape of the sheath may generally approximate a blood vessel.

[0047] Figure 4 provides a cross-sectional view of an example dilator 400 in accordance with some embodiments. The dilator 400 may have any of a variety of shapes and/or sizes. Moreover, different sections/portions of the dilator 400 may have different and/or unique shapes and/or sizes. For example, as shown in Figure 4, a dilator 400 may be composed of at least three longitudinal portions: a distal portion 420, a middle portion 422, and a proximal portion 424. Each of these portions may form a continuous device and/or may be separate portions configured to be inter-connected and/or pressed together.

[0048] Because Figure 4 provides a cross-sectional view of the dilator 400, various components of the dilator 400 are shown in a common plane. However, various components of the dilator 400 may have a three-dimensional form, which will be understood by those having skill in the art. For example, the distal portion 420 may have a conical shape and/or the middle portion 422 and/or proximal portion 424 may have cylindrical shapes around an inner lumen 402 of the dilator 400. The inner lumen 402 may represent a cylindrical or similar space within the dilator 400.

[0049] In some embodiments, the distal portion 420 may have an at least partially tapered surface. For example, between the middle portion 422 and a distal end 405 of the dilator 400, the diameter of the dilator 400 may gradually decrease to a minimal diameter at or near the distal end 405. In some embodiments, the minimal diameter of the dilator 400 may be approximately equal to a diameter of the inner lumen 402. The tapered surface of the distal portion 420 may allow the dilator 400 to more effectively dilate blood vessels. For example, a diameter of a blood vessel may be greater than the minimal diameter of the dilator 400 (e.g., at the distal end 405) but less than the maximal diameter of the dilator 400 (e.g., at the middle portion 422). Moreover, the maximal diameter/width of the dilator 400 may be approximately equal to a diameter/width of an inner lumen of a sheath (e.g., the first diameter 306 of the sheath 300 of Figure 3). Accordingly, the distal end 405 of the dilator 400 may be configured to fit into a blood vessel and, as the dilator 400 passes through the blood vessel, the distal portion 420 may be configured to gradually open and/or stretch the blood vessel until the blood vessel has an approximately equal diameter to the maximal diameter of the dilator 400 (e.g., at the middle portion 422).

[0050] The distal portion 420 may have any length and/or the tapered surface of the distal portion 420 may have any amount of slope. In some embodiments, distal portion 420 may have a generally constant slope and/or the diameter/width of the dilator may gradually increase from the distal end 405 to the middle portion 422. The outer surface of the distal portion 420 may be at least partially smooth and/or may have ridges and/or other indentations to facilitate movement of the dilator 400 through blood vessels and/or various chambers. For example, the distal portion 420 may comprise one or more ridges running generally longitudinally (i.e., from the distal end 405 toward the middle portion 422) along the surface to minimize surface contact and/or friction between the distal portion 420 and tissue of a blood vessel or chamber.

[0051] The distal portion 420 may attach to and/or may form a continuous device with the middle portion 422. In some embodiments, the dilator 400 may not comprise the middle portion 422 and/or the middle portion 422 may have a similar shape and/or size as the distal portion 422 and/or the proximal portion 424. For example, the middle portion 422 may have a generally tapered surface, similar to the distal portion 420 and/or the diameter and/or width of the middle portion 422 may be approximately equal to the proximal portion 424. In some embodiments, the diameter and/or width of the dilator 400 may generally level off at the middle portion 422. For example, the diameter and/or width of the dilator may gradually increase from the distal end 405 to the middle portion 422 and/or may maintain a maximal diameter of the proximal portion 420 at the middle portion 422. In some embodiments, a diameter and/or width of the dilator 400 at the middle portion 422 may be a maximal diameter of the dilator 400.

[0052] In some embodiments, the middle portion 422 may have an at least partially smooth surface and/or may comprise one or more ridges and/or other indentations to minimize friction between the middle portion 422 and tissue walls. For example, the middle portion 422 may have an at least partially wavy surface in which peaks of the surface have a maximal diameter/width of the middle portion 422 and/or dilator 400 and troughs of the surface have a minimal diameter/width of the middle portion 422 and/or a diameter/width approximately equivalent to a diameter/width of the proximal portion 424. In one use case, the middle portion 422 may comprise one or more generally thin ridges running laterally and/or longitudinally across the middle portion 422. In some embodiments, one or more ridges at the middle portion 422 (e.g., running longitudinally along the dilator 400) may extend into one or more ridges of the distal portion 420.

[0053] The middle portion 422 may have a generally tapered surface rather than the generally flat surface shown in Figure 4. For example, the middle portion 422 may have a tapered slope that approximates a slope of the distal portion 420 such that the tapered surface of the distal portion 420 extends in a linear or near-linear manner into the slope of the middle portion 422. In one use case, the diameter/width of the dilator may gradually decrease between the distal portion 420 and the proximal portion 424. For example, a first point 425 at which the distal portion 420 meets the middle portion 422 may represent a maximal diameter/width of the dilator 400 and the diameter/width of the dilator may gradually decrease from the first point 425 to a second point 427 at which the middle portion 422 meets the proximal portion 424. In some embodiments, a diameter/width of the dilator 400 may gradually decrease along the middle portion 422 such that a minimal diameter/width of the middle portion 422 (e.g., at the second point 427) may be approximately equal to a diameter/width of the dilator 400 at the proximal portion 424. However, a maximal diameter/width at the middle portion 422 may be at any point of the middle portion 422. For example, the middle portion 422 may form a peak at or near a mid-point or other point of the middle portion 422.

[0054] In some embodiments, the middle portion 422 may be configured to at least partially hold the dilator 400 in place. For example, at least a portion of the middle portion 422 may be configured to press against an inner surface of a sheath to hold the dilator 400 within the sheath. In some embodiments, the dilator 400 may comprise one or more mechanisms to attach to and/or hold against a sheath or other device. For example, the dilator 400 may comprise one or more hooks (e.g., at the middle portion 422) configured to engage various mechanisms of a sheath or other device. In some embodiments, ridges and/or other indentations of the dilator 400 (e.g., at the middle portion 422) may be configured to fit into and/or otherwise engage threads, grooves, indentations, and/or similar features and/or mechanisms of a sheath or other device. For example, a sheath (e.g., the sheath 300 in Figure 3) may comprise one or more threads running generally laterally along an inner surface of the sheath and the dilator 400 may comprise one or more grooves configured to receive the one or more threads such that the dilator 400 may be twisted along the threaded surface of the sheath. [0055] In some embodiments, the dilator 400 may be configured to create minimal friction between the dilator 400 and a sheath (e.g., the sheath 300 in Figure 3) while establishing and/or maintaining a connection with the sheath. In other words, the dilator 400 may be configured to form a loose connection with the sheath. For example, the dilator 400 and/or sheath may have an at least partially threaded surface configured to mate with a grooved surface of the dilator 400 and/or sheath. When the dilator 400 is mated with the sheath, threads and/or grooves of the dilator 400 and/or sheath may be large enough (i.e., deep enough, tall enough) that the dilator 400 is incapable of becoming disconnected or at least unlikely to become disconnected from the sheath. However, there may be gaps between the dilator 400 (e.g., at the middle portion 422) and the sheath such that if the dilator 400 (e.g., at least the distal portion 420) twists within the sheath, there may be minimal contact (e.g., less than a full ellipse of contact) between the dilator 400 and the sheath.

[0056] At least a portion of the proximal portion 424 may have a smaller diameter/width than a maximal diameter/width of the dilator 400. Accordingly, at least a portion of the proximal portion 424 may be configured not to contact an inner surface of an outer tube of a sheath. As shown in Figure 4, the proximal portion 424 may have a generally level diameter/width across an entire length of the proximal portion 424. However, the proximal portion 424 may have varying diameters/widths. For example, an outer surface of the proximal portion 424 may have a wavy structure and/or may comprise one or more of ridges, grooves, indentations, pegs, steps, and/or other portions at which the diameter/width of the proximal portion 424 is greater than a minimal diameter/width of the proximal portion 424.

[0057] The proximal portion 424 may be situated adjacent to the middle portion 422. In some embodiments, at least a portion of the proximal portion 424 may be configured to contact an outer tube of a sheath. The proximal portion 424 may comprise one or more protrusions, waves, pegs, ridges, and/or other features configured to extend from a portion of lesser diameter/width to a maximal diameter/width of the dilator 400. Accordingly, the proximal portion 424 may be configured to create one or more gaps between the dilator 400 and a sheath.

[0058] The proximal portion 424 may have any length. In some embodiments, the proximal portion 424 may be configured to extend out of a patient’s body. The proximal portion 424 may have an end portion which may provide an opening to the inner lumen 402 of the dilator 400. The proximal portion 424 may have a generally cylindrical form around the inner lumen 402 and/or may have any other shape. [0059] As shown in Figure 4, at least a portion of the proximal portion 424 may have a smaller diameter/width than the middle portion 422 and/or the distal portion 420. In some embodiments, the second point 427 (i.e., where the middle portion 422 meets the proximal portion 424) may represent a step-down in diameter/width from the middle portion 422 to the proximal portion 424. However, the dilator 400 may have tapered decrease in diameter/width from the middle portion 422 to the proximal portion 424.

[0060] In some embodiments, a difference between a maximal diameter/width of the dilator (e.g., at the middle portion 422) and a minimal diameter/width at the proximal portion 424 may be minimal. This is because the difference in diameter/width may need to be only large enough to create a separation between the proximal portion 424 and a sheath which may pass over the dilator 400. For example, the difference between the maximal diameter/width of the dilator and the minimal diameter/width at the proximal portion 424 may be approximately 0.015-0.040 inches. However, the proximal portion 424 may have any diameter(s)/width(s) ranging from a diameter/width of the inner lumen 402 and the maximal diameter/width of the dilator 400.

[0061] The dilator 400 may be composed of one or more of any of a variety of materials. In some embodiments, the dilator 400 may be at least partially composed of stainless steel braided Pebax and/or similar materials. The dilator 400 may be configured to have an at least partially soft structure to prevent and/or minimize damage to the tissue during the dilation process. For example, the dilator 400 may be composed of polyether block amide (PEBA) or other material with a relatively soft and/or elastic structure. In some embodiments, the middle portion 422 of the dilator 400 may have a generally soft structure to allow the middle portion 422 to at least partially compress and/or squeeze into a lumen of a sheath.

[0062] In some embodiments, the dilator 400 may be configured for delivery of one or more balloons and/or similar devices. For example, a balloon may be attached at or near the distal end 405 of the dilator 400 for use in apposing the distal end 405 of the dilator 400 to a tissue wall during a delivery process. In some embodiments, the dilator 400 may comprise multiple lumens 402. For example, the dilator may have two lumens 402, one of which may be configured for use in inflation and/or deflation of a balloon at or near the distal end 405 of the dilator 400.

[0063] The dilator 400 may be configured to cause any amount of expansion of a blood vessel. For example, the dilator 400 may create approximately or less than 2x expansion of a blood vessel. The dilator 400 may be configured to open and/or expand an area of tissue around a puncture site. In some embodiments, the lumen 402 of the dilator 400 may be configured to receive various instruments, including guidewires and/or needles. A guidewire and a needle may each be passed through the dilator 400 simultaneously and/or at different times/stages.

[0064] Figures 5A-5D illustrate delivery systems 500 including sheaths 510 and dilators 550 in accordance with some embodiments. The above discussion of the sheath 300 in Figure 3 and the dilator 400 in Figure 4 may apply to the sheath 510 and dilator 550, respectively, of Figures 5A-5D. As shown in Figures 5A-5D, the dilator 550 may be configured to fit at least partially within a lumen of the sheath 510. In some embodiments, at least a portion of a distal portion 520 of the dilator 550 may be configured to extend out of a distal end of the sheath 510. The distal portion 520 may be at least partially tapered to create gradual dilation of a blood vessel as the delivery system 500 moves through the blood vessel. In some embodiments, the sheath 510 may comprise a tapered section 512 of an outer tube 501 of the sheath 510. The tapered section 512 may be configured to gradually dilate the blood vessel. As shown in Figures 5A-5D, the distal portion 520 of the dilator 550 may be configured to be aligned with the tapered section 512 of the sheath 510 to create an even taper extending from a distal end 505 of the dilator 550 through the tapered section 512 of the sheath 510.

[0065] In some embodiments, a middle portion 522 of the dilator may be configured to be situated at least partially and/or completely within the lumen of the sheath 510. At least a portion of the middle portion 522 may be configured to be placed in contact with an inner surface 501a of the sheath 510. For example, a diameter/width of at least a portion of the middle portion 522 may be approximately equal to a diameter/width of the lumen of the sheath 510. The middle portion 522 may be configured to maintain contact with the inner surface 501a due to friction and/or one or more connection mechanisms between the sheath 510 and the dilator 550. In some embodiments, the sheath 510 and dilator 550 can be locked together (e.g., at the middle portion 522) by a tight seal lock design.

[0066] The dilator 550 may be configured to move independently of the sheath 510 and/or the sheath 510 may be configured to move independently of the dilator 550. In one use case, the dilator 550 may be configured to move in a longitudinal direction 521 with respect to the sheath 510. For example, the dilator 550 may move longitudinally to extend further out of the sheath 510. In another use case, the dilator 550 may be configured to twist, torque, and/or rotate with respect to the sheath 510. For example, the dilator 550 may be configured to twist about an inner lumen 502 and/or other central point of the dilator 550. For example, a surgeon may twist a proximal end of the dilator 550 (e.g., situated outside the body) laterally while the dilator 550 is at least partially within the sheath 510 and/or within a patient’s body. In some embodiments, twisting a proximal end of the dilator 550 may cause an approximately equal amount of twisting at the distal portion 520 of the dilator 550 (i.e., there may be a one-to-one correspondence between the proximal end and the distal portion 520.

[0067] The delivery system 500 may be configured to have one or more gaps 513 between the sheath 510 and the dilator 550. The one or more gaps 513 may represent portions of the lumen of the sheath 510 which may not be filled by the dilator 550. Figure 5A illustrates an example delivery system 500 in which a gap 513 may be an elliptical ring and/or tubular space around the dilator 550 and/or between the dilator 550 and the sheath 510. In some embodiments, the middle portion 522 may be configured to create a seal and/or a complete seal with the sheath 510 such that no blood and/or other fluid and/or gas may be able to flow into the one or more gaps 513. In this way, there may be no and/or minimal friction at the sheath 510 and/or dilator 550 where there is a gap 513 between the sheath 510 and dilator 550. A gap 513 may have any size. In some embodiments, a gap 513 may be a separation of 0.015-0.050 inches between the sheath 510 and at least a portion of the dilator 550.

[0068] In some embodiments, the dilator 550 may have portions having lesser diameters/widths than a maximal diameter/width of the dilator 550, thus creating at least some of the one or more gaps 513 between the sheath 510 and the dilator 550. For example, there may not be any gaps 513 between the middle portion 522 of the dilator 550 and the sheath 510 but there may be gaps 513 between the proximal portion 524 of the dilator 550 and the sheath 510. In some embodiments, there may be multiple separate gaps between the sheath 510 and the dilator 550. For example, a gap 513 may be divided into multiple separate gaps 513 by one or more partitions, walls, barriers, and/or other segments extending from the dilator 550 (e.g., from the proximal portion 524) to contact and/or nearly contact the inner surface 501a of the sheath 510.

[0069] Figure 5B illustrates an embodiment of a delivery system 500 in which the proximal portion 524 of the dilator 550 has an uneven and/or wavy outer surface. In some embodiments, the uneven surface of the proximal portion 524 may comprise one or more peak portions 531 configured to extend to and/or near the inner surface 501a of the sheath 510. The proximal portion 524 may further comprise one or more trough portions 533 configured to form gaps 513 between the dilator 550 and the sheath 510. In some embodiments, the dilator 550 may comprise multiple peak portions 531 and/or trough portions 533, thereby creating multiple gaps 513 between the dilator 550 and the sheath 510. While the middle portion 522 of the dilator 550 is shown in Figure 5B having a generally flat surface, the middle portion 522 may have an uneven and/or wavy surface similar to the proximal portion 524. In some embodiments, a peak portion 531 and/or a trough portion 533 may extend along a full circumference of the dilator 550 (e.g., around the inner lumen 502).

[0070] Figure 5C illustrates another embodiment of a delivery system 500 in which the proximal portion 524 of the dilator 550 comprises one or more protrusions 535. In some embodiments, the one or more protrusions 535 may be configured to extend from the dilator 550 to the inner surface 501a of the sheath 510. Other portions of the proximal portion 524 (e.g., portions of the dilator 550 between two protrusions 535) may be configured to form a gap 513 between the dilator 550 and the sheath 510. In some embodiments, the dilator 550 may comprise at least one protrusion 535 to create multiple gaps 513 between the dilator 550 and the sheath 510. While the middle portion 522 of the dilator 550 is shown in Figure 5C having a generally flat surface, the middle portion 522 may have an uneven surface and/or may comprise one or more protrusions 535 similar to the proximal portion 524. In some embodiments, a protrusion 535 may extend along a full circumference of the dilator 550.

[0071] Figure 5D illustrates another embodiment of a delivery system 500 in which the proximal portion 524 of the dilator 550 has an uneven and/or threaded outer surface. In some embodiments, the uneven surface of the proximal portion 524 may comprise one or more threads 537 configured to extend to and/or near the inner surface 501a of the sheath 510. The proximal portion 524 may further comprise portions between the thread(s) 537 configured to form one or more gaps 513 between the dilator 550 and the sheath 510. In some embodiments, the dilator 550 may comprise multiple threads 537 and/or a single thread passing multiple times in a helical or similar pattern around the outer surface of the dilator 550, thereby creating multiple gaps 513 between the dilator 550 and the sheath 510. While the middle portion 522 of the dilator 550 is shown in Figure 5B having a generally flat surface, the middle portion 522 may have an uneven and/or threaded surface similar to the proximal portion 524.

[0072] The dilator 550 may comprise a lumen 502 configured to receive various instruments. For example, a shunt needle may be configured to pass through the lumen 502 and out the distal end 505 of the dilator 550 and/or may be delivered to a tissue wall (e.g., a coronary sinus wall). In some embodiments, a needle or other instrument may have a curved, bent, spiraled, and/or other configuration while within the lumen 502 and/or after exiting the lumen 502. For example, a needle may be composed of Nitinol and/or another shape-memory alloy and may be shaped to have a curved end. As the needle passes through the lumen 502 (which may have a generally straight form), the needle may at least somewhat straighten out to fit within the lumen 502. As the needle exits the lumen 502, the needle may assume a curved and/or other pre-determined configuration. For example, the needle may curve to extend approximately perpendicularly and/or tangentially (i.e., at an approximately 90° angle) from the distal end 505 of the dilator 550. In this way, the needle may be configured to contact and/or penetrate a tissue wall (e.g., the coronary sinus) that may be generally parallel to the dilator 550.

[0073] The dilator 550 and/or sheath 510 may be configured to move through a vessel in a first direction led by the distal portion 520 of the dilator 550 and/or in a second direction led by the proximal portion 524 of the dilator 550. In some embodiments, the dilator 550 may have an inner lumen 502 which may pass through the distal portion 520, the middle portion 522, and/or the proximal portion 524. The inner lumen 502 may be accessible via one or more openings at the distal end 505 and/or the proximal end of the dilator 550 and may be configured to allow guidewires and/or other devices to pass through the dilator 550 and/or sheath 510. In some embodiments, the inner lumen 502 may be positioned at or near a center point of the dilator 550. For example, any lateral (i.e., into the page of Figures 5A-5D) cross- section of the dilator 550 may include the inner lumen 502 at and/or around a center point of the dilator 550. However, the inner lumen 502 may be situated at any position of the dilator 550.

[0074] The dilator 550 and/or sheath 510 may be configured to dilate and/or pre dilate a blood vessel. In some embodiments, a maximal diameter of the dilator 550 and/or sheath 510 may be larger than a diameter of a blood vessel. As the dilator 550 and/or sheath 510 moves through the blood vessel, the dilator 550 and/or sheath 510 may be configured to stretch and/or otherwise dilate the blood vessel to create a greater diameter at the blood vessel. Accordingly, as the dilator 550 and/or sheath 510 moves through the blood vessel, the dilator 550 and/or sheath 510 may contact and/or rub against inner walls of the blood vessel.

[0075] As shown in Figures 5A-5D, the dilator 550 may have a reduced diameter/width at the proximal portion 524. In some embodiments, at least a portion of the proximal portion 524 may have a maximal diameter (e.g., the diameter at the middle portion 522) of the dilator 550 and/or the dilator 550 may have one or more indentations at an outer surface of the dilator 550 (e.g., at the proximal portion 524). The indentations may be configured to reduce surface contact between the dilator 550 and the sheath 510 as the dilator 550 is twisted, torqued, rotated, extended, retracted, tilted, and/or otherwise moved with respect to the sheath 510. The indentations may provide a decrease in radius and/or diameter of the dilator 550. In some embodiments, one or more of the indentations may have a shape of an ellipse or other shape. The indentations may represent removed material from the dilator 550. In this way, an amount of surface area of the dilator 550 having a maximal radius may be reduced due to the indentations. In some embodiments, the indentations may reduce a surface area of the dilator 550 having a maximal radius of the dilator.

[0076] Indentations may have any shape. For example, an indentation may have a circular, rectangular, or triangular shape. In some embodiments, the one or more indentations may comprise one or more thin, shallow grooves which may have a straight, curved, wavy, and/or other shape.

[0077] In some embodiments, the outer surface of the dilator 550 and/or sheath 510 may have an at least partially tapered structure. For example, a distance from the outer surface of the dilator 550 and/or sheath 510 to a center point of the dilator 550 and/or sheath 510 (e.g., the lumen 502) may gradually increase from the distal end and/or the proximal end to the middle portion 522 of the dilator 550.

[0078] The dilator 550 may be configured to torque, rotate, and/or twist in either direction and/or to any degree while at least partially within the sheath 510. For example, the dilator 550 may be configured to rotate up to and/or exceeding 360° in either direction to a desired position. Accordingly, a surgeon may be able to twist the dilator 550 as desired such that a needle and/or other instrument passed through the lumen 502 may be configured to exit the distal end 505 of the dilator 550 in a desired orientation. For example, the dilator 550 may be twisted to position at which a needle inserted through the lumen 502 may exit the dilator 550 and contact and/or pierce a tissue wall. In some embodiments, the dilator 550 and/or sheath 510 may be at least partially coated in and/or composed of a generally lubricious material to facilitate movement of the dilator 550 and/or sheath 510 with respect to each other. For example, the dilator 550 and/or sheath 510 may be at least partially composed of high-density polyethylene (HDPE) and/or other materials. In some embodiments, the dilator 550 and/or sheath 510 may be at least partially coated (e.g., at an outer surface of the dilator 550 and/or the inner surface 501a of the sheath 510) with a hydrophilic coating.

[0079] In some embodiments, a needle and/or other instrument configured to fit within the lumen 502 of the dilator 550 may be locked with and/or otherwise attached to the dilator 550. For example, the dilator 550 and/or needle may each have one or more clasps, hooks, grooves, ridges, and/or similar locking mechanisms configured to hold the dilator 550 and the needle together. In this way, when the dilator 550 is twisted, the needle may twist with the dilator 550. In some embodiments, twisting the dilator 550 may cause twisting of the needle without use of locking mechanisms. For example, the size and/or shape of the lumen 502 of the dilator 550 may be configured to create a tight and/or “snug” fit with the needle such that movement of the dilator 550 may cause the needle to move through friction between the dilator 550 and the needle.

[0080] In some embodiments, the dilator 550 and sheath 510 may be configured to be locked together during and/or after delivery. The dilator 550 and sheath 510 may further be configured to be unlocked post-delivery and the dilator 550 can be advanced forward (i.e., out of the sheath 510) and/or the sheath 510 can be pulled backwards while the dilator 550 may be held in place. In some embodiments, a guidewire may be used to push the dilator 550 out of the sheath 510. The guidewire may be configured to be removed and/or a shunt needle and/or other instruments may be advanced through the sheath 510 and/or dilator 550. The sheath 510 and/or dilator 550 may comprise one or more stoppers at proximal ends of the sheath 510 and/or dilator 550.

[0081] The sheath 510 may be tilted in any direction as desired to orient the dilator 550 and/or a needle passed through the dilator 550 a desired puncture location. The sheath 510 may be flexed as desired to point the dilator 550 towards the puncture location.

For example, a proximal end of the dilator 550 and/or sheath 510 may be accessible to a surgeon and may be tilted and/or flexed to cause tilting of the distal portion 520 of the dilator 550.

[0082] Delivery systems as described herein may be used to position sheaths and/or dilators to various areas of a human heart. For example, a dilator and/or sheath may be configured to pass from the right atrium into the coronary sinus. However, it will be understood that the description can refer or generally apply to positioning of sheaths and/or dilators from a first body chamber or lumen into a second body chamber or lumen, where the sheaths and/or dilators may be bent when positioned from the first body chamber or lumen into the second body chamber or lumen. A body chamber or lumen can refer to any one of a number of fluid channels, blood vessels, and/or organ chambers (e.g., heart chambers). Additionally, reference herein to “catheters,” “tubes,” “shafts,” “sheaths,” “steerable sheaths,” and/or “steerable catheters” can refer or apply generally to any type of elongate tubular delivery device comprising an inner lumen configured to slidably receive instrumentation, such as for positioning within an atrium or coronary sinus, including for example delivery catheters and/or cannulas. It will be understood that other types of medical implant devices and/or procedures can be delivered to the coronary sinus using a delivery system as described herein, including for example ablation procedures, drug delivery and/or placement of coronary sinus leads.

[0083] Figures 6A and 6B illustrate an example needle 609 delivery process for a delivery system 600 including a dilator 650, sheath 610, and/or a needle 609. A needle 609 (e.g., a puncture needle and/or similar device) may be configured to pass through an inner lumen 602 of the dilator 650 and/or sheath 610 while the dilator 650 and/or sheath 610 is/are positioned within a blood vessel 605. The terms “needle” and/or “means for penetrating” are used herein according to their broad and ordinary meaning and may refer to any needle, wire, suture, pin, and/or other line or device configured to pass through a lumen of a dilator, sheath, and/or other delivery device and/or penetrate a wall of a blood vessel.

[0084] In some embodiments, the needle 609 may have a pre-defined shape. For example, the needle 609 may be at least partially composed of Nitinol and/or a similar material having shape-memory characteristics. The needle 609 may be configured to pass through the inner lumen of the dilator 650 and/or exit a distal end of the dilator 650 such that the needle 609 may be exposed to the blood vessel 605. In some embodiments, the needle 609 may have a curved and/or coiled form such that when the needle 609 exits the dilator 650 and/or sheath 610, the needle may naturally curve and/or bend towards a wall of the blood vessel 605. In some cases, when the delivery system 600 arrives at desired position within the blood vessel 605, the needle 609 may exit the dilator 650 and/or sheath 610 in a direction and/or may curve/bend in a direction that is away from a target puncture location 611. In such cases, at least some components of the delivery system 600 may be configured to twist while within the blood vessel 605 such that the needle 609 may be directed towards the target puncture location 611 (see Figure 6B).

[0085] In some embodiments, the dilator 650 and/or needle 609 may be configured to twist with respect to the sheath 610 and/or blood vessel. That is, the sheath 610 may be configured not to twist when the dilator 650 and/or needle 609 are twisted. In some embodiments, the presence of one or more gaps 613 between the dilator 650 and sheath 610 may reduce surface contact and/or friction between the dilator 650 and sheath 610 to improve an ease and/or effectiveness of twisting the dilator 650 with respect to the sheath 610.

[0086] Twisting the dilator 650 (e.g., by a surgeon) may cause twisting (e.g., approximately a one-to-one ratio) of the needle 609. For example, contact and/or friction between the dilator 650 and needle 609 may cause reciprocal movement, including twisting, between the dilator 650 and the needle 609. In some embodiments, the needle 609 may be attached and/or locked to the dilator 650 to facilitate reciprocal movement between the dilator 650 and the needle 609. By allowing for twisting (including simpler and/or more effective twisting) of the dilator 650 and/or needle 609 within the blood vessel 605 and/or sheath 610, the delivery system 600 may provide a more simple and/or effective delivery process for surgeons. For example, surgeons may not be required to precisely position a delivery sheath and/or a needle during an initial stage of the delivery process as some displacement and/or improper positioning of the needle 609 may be corrected after the delivery system 600 is positioned at a desired location within the blood vessel 605. While the dilator 650 is shown within a sheath 610, the dilator 650 may be configured for use without a sheath 610 in some cases.

[0087] Figure 7 is a flow diagram of a process 700 for deploying a delivery system including a dilator and a sheath into and/or through a blood vessel. In block 702, the process 700 involves providing a dilator situated at least partially within a sheath.

[0088] In block 704, the process 700 involves introducing the sheath and dilator into a vessel (e.g., a blood vessel) and/or chamber of the body. The sheath and dilator may be locked together via one or more locking mechanisms. In some embodiments, the dilator may be held within the sheath at least partially based on friction between at least a portion of the dilator and the sheath. The sheath may have an inner lumen and/or may comprise an outer tube at least partially surrounding a hollow interior configured to fit at least a portion of the dilator. The dilator may fit entirely within the sheath and/or at least a portion of the dilator (e.g., a distal portion) may be configured to extend out of the sheath.

[0089] At least a portion of the dilator may be configured to fit tightly within the sheath without a gap between the portion of the dilator and the sheath. The portion may comprise a cylindrical and/or spiral section of the dilator configured to establish a complete or near complete ellipse of contact between the dilator and the sheath. At least partially based on the tight fit between the portion of the dilator and the sheath, the dilator may be held in place by friction. In some embodiments, one or more locking and/or engaging mechanisms (e.g., grooves, ridges, pegs, hooks, guide tracks, etc.) may be configured to interconnect the sheath and the dilator.

[0090] In some embodiments, at least a portion of the dilator may be configured not to contact the sheath. For example, the portion may have a diameter/width that is less than a maximal diameter/width of the dilator and/or a diameter/width of the hollow interior of the sheath. Accordingly, when the portion is within the sheath, the portion may not contact the sheath. [0091] In block 706, the process 700 involves inserting a puncture needle through a lumen of the dilator. The needle may be inserted through the lumen of the dilator before the dilator is inserted into the body or after the dilator is situated within the body. In some embodiments, one or more locking mechanisms may be configured to hold the needle and dilator together such that when the dilator is twisted, tilted, or otherwise moved, the needle may move with the dilator.

[0092] In block 708, the process involves twisting the dilator to align the needle with a desired puncture location. In some embodiments, the needle may have an at least partially curved form. Accordingly, aligning the needle with the puncture location may involve situating the needle such that when the needle exits the dilator and curves (e.g., tangentially to the dilator), the needle may contact the puncture location.

[0093] In block 710, the process 700 involves advancing the needle out of the dilator and to the puncture location. The needle may be configured to contact and/or penetrate tissue at the puncture location.

[0094] Depending on the embodiment, certain acts, events, or functions of any of the processes or algorithms described herein can be performed in a different sequence, may be added, merged, or left out altogether. Thus, in certain embodiments, not all described acts or events are necessary for the practice of the processes.

[0095] Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is intended in its ordinary sense and is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous, are used in their ordinary sense, and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is understood with the context as used in general to convey that an item, term, element, etc. may be either X, Y or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y and at least one of Z to each be present.

[0096] It should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than are expressly recited in that claim. Moreover, any components, features, or steps illustrated and/or described in a particular embodiment herein can be applied to or used with any other embodiment(s). Further, no component, feature, step, or group of components, features, or steps are necessary or indispensable for each embodiment. Thus, it is intended that the scope of the inventions herein disclosed and claimed below should not be limited by the particular embodiments described above, but should be determined only by a fair reading of the claims that follow.

[0097] It should be understood that certain ordinal terms (e.g., “first” or “second”) may be provided for ease of reference and do not necessarily imply physical characteristics or ordering. Therefore, as used herein, an ordinal term (e.g., “first,” “second,” “third,” etc.) used to modify an element, such as a structure, a component, an operation, etc., does not necessarily indicate priority or order of the element with respect to any other element, but rather may generally distinguish the element from another element having a similar or identical name (but for use of the ordinal term). In addition, as used herein, indefinite articles (“a” and “an”) may indicate “one or more” rather than “one.” Further, an operation performed “based on” a condition or event may also be performed based on one or more other conditions or events not explicitly recited.

[0098] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0099] Although certain preferred embodiments and examples are disclosed below, inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and to modifications and equivalents thereof. Thus, the scope of the claims that may arise herefrom is not limited by any of the particular embodiments described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain embodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and/or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.

[0100] The spatially relative terms “outer,” “inner,” “upper,” “lower,” “below,” “above,” “vertical,” “horizontal,” and similar terms, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case where a device shown in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in the other direction, and thus the spatially relative terms may be interpreted differently depending on the orientations.

[0101] Unless otherwise expressly stated, comparative and/or quantitative terms, such as “less,” “more,” “greater,” and the like, are intended to encompass the concepts of equality. For example, “less” can mean not only “less” in the strictest mathematical sense, but also, “less than or equal to.”

Claims

WHAT IS CLAIMED IS:

1. A delivery system comprising: a sheath having an outer tube surrounding a hollow interior; and a dilator configured to fit at least partially into the hollow interior of the sheath, the dilator comprising: a distal portion configured to at least partially dilate a blood vessel; a middle portion; a proximal portion; and an inner lumen extending through the distal portion, middle portion, and the proximal portion.

2. The delivery system of claim 1, wherein the dilator has a cylindrical shape around the inner lumen.

3. The delivery system of claim 1 or claim 2, wherein the distal portion has an at least partially tapered surface.

4. The delivery system of any of claims 1-3, wherein the middle portion is situated between the distal portion and the proximal portion.

5. The delivery system of claim 4, wherein the middle portion has a maximal diameter of the dilator.

6. The delivery system of any of claims 1-5, wherein a diameter at the proximal portion is less than a maximal diameter of the dilator.

7. The delivery system of any of claims 1-6, wherein there is at least one gap between the dilator and the sheath when the dilator is situated within the hollow interior of the sheath.

8. The delivery system of claim 7, wherein the at least one gap is between the proximal portion and the sheath.

9. The delivery system of claim 8, wherein the proximal portion is configured not to contact the sheath.

10. The delivery system of any of claims 7-9, wherein there are no gaps between the middle portion and the sheath.

11. The delivery system of any of claims 1-10, wherein the inner lumen of the dilator is configured to fit a puncture needle.

12. The delivery system of any of claims 1-11, wherein the dilator is configured to twist while situated at least partially within the hollow interior of the sheath.

13. The delivery system of claim 12, wherein twisting the dilator is configured to cause twisting of a puncture needle within the inner lumen of the dilator.

14. The delivery system of any of claims 1-13, wherein the dilator is configured to tilt while situated at least partially within the hollow interior of the sheath.

15. A dilator configured to fit at least partially into a hollow interior of a sheath, the dilator comprising: a distal portion configured to at least partially dilate a blood vessel; a middle portion; a proximal portion; and an inner lumen extending through the distal portion, the middle portion, and the proximal portion.

16. The dilator of claim 15, wherein the middle portion has a cylindrical shape around the inner lumen.

17. The dilator of claim 15 or claim 16, wherein the distal portion has an at least partially tapered surface.

18. The dilator of any of claims 15-17, wherein the middle portion is situated between the distal portion and the proximal portion.

19. The dilator of claim 18, wherein the middle portion has a maximal diameter of the dilator.

20. The dilator of claims 15-19, wherein a diameter at the proximal portion is less than a maximal diameter of the dilator.

21. The dilator of claims 15-20, wherein the proximal portion is configured to form at least one gap between the proximal portion and the sheath.

22. The dilator of claim 21, wherein the proximal portion is configured not to contact the sheath.

23. The dilator of claims 15-22, wherein the middle portion is configured to form a gapless contact with the sheath.

24. The dilator of claims 15-23, wherein the inner lumen is configured to fit a puncture needle.

25. The dilator of claims 15-24, wherein the distal portion is configured to twist while situated at least partially within the sheath.

26. The dilator of claim 25, wherein twisting the distal portion is configured to cause twisting of a puncture needle within the inner lumen at the distal portion.

27. The dilator of claims 15-26, wherein the distal portion is configured to tilt while situated at least partially within the sheath.

28. A method comprising: introducing a sheath and a dilator into a blood vessel, wherein the dilator is situated at least partially within the sheath, and the dilator comprises an inner lumen; inserting a needle through the inner lumen of the dilator; twisting the dilator to cause twisting of the needle to a desired position; and advancing the needle out of a distal end of the dilator.

29. The method of claim 28, wherein there is at least one gap between the dilator and an inner surface of the sheath.

30. The method of claim 29, wherein at least a portion of the dilator forms a gapless contact with the sheath.