Endovascular delivery system and method

Abstract

A delivery catheter for delivering a pacemaker lead into cardiac tissue. The catheter includes a distal end with a tip having an electrode configured for unipolar ablation of cardiac tissue that provides a breach of the endocardium while minimizing trauma to the patient.

Description

[0001]ENDOVASCULAR DELIVERY SYSTEM AND METHOD Field of the Invention The present disclosure relates to improvements in devices and methods in the field of cardiac electrophysiology. Background of the Invention Conduction system pacing (CSP) has rapidly become established as a fundamental paradigm shift in pacemaker lead implantation for the mitigation and avoidance of heart failure in the past decade. In comparison to conventional lead placement techniques in the right ventricular septum or apex, CSP may potentially introduce new challenges in the optimisation of lead deployment. Specifically, in contrast to traditional pacing lead placement approaches, CSP introduces new complexities in relation the achievement of safe and reliable tunnelling of leads to the desired depth and position in the septum. The interplay of biomechanical properties and electrophysiological characteristics within the cardiac conduction system, coupled with their dynamic interaction with a pacing lead is important in the performance of CSP. The emerging data showing benefit of LBBAP compared to His Bundle pacing highlights the importance of this complex interaction and the effects they have on success of CSP. One of the primary interactions that contribute to failure of lead deployment is endocardial entanglement, which occurs often during CSP lead deployments. Endocardial entanglement is likely a result of the complex dynamics between the pacemaker lead and the endomyocardial tissues, which can hinder the lead from properly anchoring into the desired position within the heart. In addition to the above, conventional thought is that a surgeon does not want to use a cutting tool within the heart due to the danger of creating a catastrophic laceration, resulting in patient death. The present inventors of the system and method described below have discovered that creating a pre-lead insertion breach in a cardiac wall, followed by pacemaker lead insertion and placement, results in surprisingly better patient outcomes, with a much improved conductor placement within cardiac tissue. It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country. Summary The present disclosure in one preferred aspect provides for a method for pacemaker lead implantation into a heart of a patient. The method includes positioning a catheter within the heart, the catheter having a distal end for insertion first into the patient; breaching a wall of an endocardium or a septum of the heart to create a lead insertion opening in the wall; moving a pacemaker lead beyond the distal end of the catheter and into the lead insertion opening after the wall is breached; and anchoring the pacemaker lead within the wall through the lead insertion opening created. In another preferred aspect, there is provided an endovascular delivery system. The system includes a delivery catheter having a distal end for insertion first into a heart of a patient. The system includes a wall-breaching device configured to create a breach in a wall of an endocardium or a septum of the heart. The breaching device is operable to create the breach without rotation. The breaching device is extendable beyond the distal end of the catheter. In a further preferred aspect, there is provided another endovascular delivery system. The system includes a delivery catheter having a distal end for insertion first into a heart of a patient. The system includes an inner catheter having a distal end extendible beyond the distal end of the delivery catheter, the distal end of the inner catheter including a sharp blade with an elongated cutting surface for cutting cardiac tissue. In an additional further preferred aspect, there is provided a delivery catheter for delivering a pacemaker lead. The catheter includes a catheter body with a distal end for insertion first into cardiac tissue; a proximal end opposite the distal end along a central longitudinal axis; and a central lumen from the proximal end to the distal end. The catheter further includes an electrode at the distal end; and a conductor wire oriented along a length of the catheter body from the proximal end to the distal end, the conductor wire connecting the electrode to an energy source. In an additional preferred aspect, there is provided a method for implanting a pacemaker lead into a patient. The method includes inserting a delivery catheter into the patient, the delivery catheter including an electrode at a distal end thereof; breaching cardiac tissue with the electrode of the delivery catheter; and inserting the pacemaker lead through the delivery catheter and electrode into the patient. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. In the present specification and claims, the word “comprising” and its derivatives including “comprises” and “comprise” include each of the stated integers, but does not exclude the inclusion of one or more further integers. It will be appreciated that reference herein to “preferred” or “preferably” is intended as exemplary only. The claims as filed and attached with this specification are hereby incorporated by reference into the text of the present description. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. Brief Description of the Figures Fig.1 is a partial perspective view of a heart. Fig.1A is a partial cross sectional view of the heat shown in Fig.1, showing different anatomical structures and regions of the heart. Fig.2 is a partial cross sectional view of the heart of Fig.1A with a pacemaker lead engaged therein in accordance with a preferred embodiment of the present disclosure. Fig.2A is an expanded view along section A of Fig.2 showing a distal end of the pace maker lead of Fig.2 engaged with a septum of the heart of Fig.1A. Fig.3 is a perspective view of a catheter and insertion tool engaged to the heart. Fig.3A is a partial perspective cross sectional view of an endovascular delivery system including a delivery catheter with an inner catheter having a cutting blade at the leading end of the inner catheter. Fig.3B is a partial cross sectional view of the endovascular delivery system of Fig. 3A with the inner catheter in a deployed position so that the blade extends from the distal end of the delivery catheter. Fig.3C is a partial cross sectional view of the endovascular delivery system in accordance with another preferred embodiment with an inner catheter having a conductor wire therein, with a portion exposed at the distal end of the delivery catheter. Fig.3D is a partial perspective view of the endovascular delivery system of Fig.3C showing a trailing end of the conductor wire of Fig.3C engageable with an energy source. Fig.4 is a side view of an endovascular delivery system including a delivery catheter a distal end having a tip with an electrode, and a proximal end with a hub connected to a socket to plug into a power source in accordance with another preferred embodiment of the present description. Fig.5 is a longitudinal cross sectional view of the catheter of Fig.4. Fig.6 is a partial cross sectional leading end view of the catheter tip of Fig.4, the tip being configured for unipolar ablation. Fig.7 is a cross sectional side view of a catheter with the catheter tip of Fig.6 engaged with cardiac tissue, and a pacemaker lead being inserted through the catheter. Fig.8 is a cross sectional side view of the catheter and tip of Fig.7, with the pacemaker lead shown inserted into the cardiac tissue. Fig.9 is a partial perspective view of the catheter of Fig.4 connected with a haemostatic valve and flush port. Fig.10 is a partial perspective cross sectional view of the catheter tip of Fig.4 shown inserted into the left ventricle of cardiac tissue. Detailed Description of the Drawings Reference will now be made in detail to the present preferred embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Figs.1 to 2A show the anatomical structure of a typical human heart muscle relevant to illustrate application of endovascular delivery system 100 in a cardiac environment. Although described in relation to a human, it will be appreciated that principles described herein may be applied to other animals as appropriate (e.g., agricultural animals and / or pets). As would be appreciated by those of ordinary skill in the field, the heart contains the right atrium, left atrium, right ventricle, and left ventricle as shown in Figs.1A and 2. The endocardium is the innermost layer of tissue lining the heart chambers. The septum separates the right and left sides of the heart. Figs.3 to 3B show various components of endovascular delivery system 100, and their general arrangement with one another. Fig.3 shows an insertion tool 102 with a shaft 104 inserted through delivery catheter 23 leading to the heart. Figs.3A and 3B show delivery catheter 23 that includes an inner catheter 22 moveable therein along a central longitudinal axis of delivery catheter 23. A distal end 106 of inner catheter 22 preferably includes a mechanical cardiac wall breaching device or mechanism in the form of a cutting blade 24. Blade 24 is preferably constructed from a metallic material such as steel. Blade 24 preferably is dimensioned with a length greater than its width. As shown in Fig.3B, blade 24 is preferably configured so that it has two diagonal cutting edge surfaces 108, 110 extending from a blade base, and terminating at a distal point 112. Blade 24 is configured to cut, cleave, lacerate, slice, or otherwise separate tissue fibres when applied thereto. Blade 24 may be configured without a central point if desired. For example, the blade may have just a single diagonal cutting surface terminating at an apex formed at the intersection of the diagonal cutting surface, and a linear side edge parallel with the central longitudinal axis of inner catheter 22. Referring further to Fig.3B, inner catheter 22 is configured to extend to a maximal preset distance so that cutting blade 24 extends no further than the preset distance. A range of suitable preset depth distances include between 2 to 4 mm. One example of a suitable preset distance is 3 mm, so that the cutting blade penetrates no deeper than 3mm into the cardiac tissue. Such a depth is sufficient to penetrate the endocardium, and create an initial crevice into which a pacemaker lead 19 (Fig. 2A) is inserted. In use, referring to Figs.3A and 3B, to create a breach through the endocardium, a healthcare professional moves inner catheter 22 distally through outer, delivery catheter 23. Blade 24 exits distal end 114 of outer catheter 23 to extend distally into the endocardium. Blade 24 then cuts the endocardium. Blade 24 is preferably depth-limited so that the blade penetrates no more than a preset depth, in this example, 3mm. If desired, blade 24 may be moved transverse to the direction of insertion to create a lateral incision as needed for a particular procedure. Once a breach is created in the endocardium, or septum if ultimate lead placement is desired at the septum, blade 24 is retracted and withdrawn. Thereafter, pacemaker lead 19 (Fig.2A) is first advanced into the breach in a linear direction, then rotated further into cardiac tissue, preferably to a depth of approximately 9 to 10mm. It will be appreciated that the steps described above may be performed in a different order, varied, or some steps omitted entirely without departing from the scope of the present disclosure. For example, rather than advancing pacemaker lead 19 initially in a linear direction into the cardiac tissue through the breach, pacemaker lead 19 may be rotated entirely (without linear advancement) to advance the lead out of the delivery catheter into the cardiac tissue. Once the pacemaker lead is inserted into the cardiac tissue, breaching either endocardium tissue outside of the septum, or at the septum, the pacemaker lead is anchored within the wall through the lead insertion opening created by the breach. In a preferred aspect, the breach in the wall is created without rotation of any device used to breach the wall. For example, if blade 24 is used to breach the wall, blade 24 is inserted in a linear direction without rotation to create the lead insertion opening for later placement of the pacemaker lead. Referring now to Figs.3C and 3D, an endovascular delivery system 200 is shown in accordance with another preferred embodiment of the present disclosure. System 200 is similar to system 100 except that a tissue breaching means using electricity is utilized rather than blade 24. In particular, Fig.3C shows inner catheter 22 containing coiled conductor wire 26 to deliver thermal energy, for example, radio frequency energy. In an initial deployed position, wire 26 is exposed at position 27 beyond distal end 214 of outer catheter 23. As shown in Fig.3D, outer catheter 23 in a ready-to-deploy position has exposed conductor wire extending beyond distal end 214 at position 27. Catheter 23 has a proximal end 216 where conductor wire cable 28 extends, travelling to socket 29. Socket 29 is preferably configured to plug into a fitting at an energy source 30. Energy source 30 is preferably configured to power an ultrasonic device having an ultrasonic transducer to create a breach in the cardiac tissue, in addition to, or in place of the cutting blade. Other breaching mechanisms may be provided as desired. For example, catheter 22 may be provided with a thermal coupling, or a laser device to separate cardiac fibre tissue. Referring now to Figs.4 to 8, an endovascular delivery system 300 is shown in accordance with another preferred embodiment of the present disclosure. System 300 is similar to system 200 except that electrode at the tip is structured differently, preferably as a ring. System 300 is configured to accommodate a unipolar electrical dispersion. System 300 will now be described in detail as follows. Fig.4 shows system 300 including a catheter 318 having a catheter body 320 with a distal end 322 for insertion first into cardiac tissue, and a proximal end 324 opposite distal end 322 along a central longitudinal axis. Distal end 322 includes a tip 326. Proximal end 324 includes a hub 328 to connect a wire cable 330 to a power source via a socket 332. Fig.5 shows the internal structure of catheter body 320. Catheter body 320 is configured with a central or inner lumen 334 adapted for pacemaker lead movement therethrough. Catheter body 320 also includes a wire lumen 336 sandwiched between inner lumen 334 and an outer surface 338 of body 320 to convey and house a connecting wire 340. Wire lumen 336 extends around a majority of the outer circumference of inner lumen 334. As shown in Fig.4, wire 340 connects an electrode at tip 326 to a socket 332 for connection to a power source (using cable 330 at proximal end 324). As shown in Fig.6, tip 326 includes an external electrode 342 for emitting thermal energy to an area in the cardiac tissue to modify and create a breach in the cardiac tissue for pacemaker lead insertion. Preferably, the thermal energy is delivered as radio frequency (RF) energy by wire 340. Tip 326 preferably includes a fillet 344 to secure electrode 342 to catheter body 320. With continued reference to Fig.6, electrode 342 is preferably configured as an external ring encircling the central longitudinal axis of body 320. It will be appreciated that electrode 342 may reside completely within the tip of the body; extend from the distal end of the body; or be partially within the body and extend distally from the body, as desired. System 300 also includes a dispersive electrode 346, placed proximate the cardiac tissue remotely from ring electrode 342 as shown in Fig.7. Having described the preferred components of system 300, a preferred method of use will now be described with reference to Figs.4, 7, 8 and 10. Socket 332 is connected to a power source 348. Catheter 318 is inserted into a patient. The distal end of delivery catheter 318 is moved forward and placed against the endocardium 10 of cardiac tissue 12 so that electrode 342 is proximate, preferably contacting cardiac tissue 12. Thermal energy preferably in the form of RF energy is delivered via wire 340 to electrode 342 to cause a modification or breach 14 of the cardiac tissue. The size of the modification may be influenced by the distance of dispersive electrode 346 compared to ring electrode 342. Thereafter, as shown in Figs.8 and 10, pacing lead (pacemaker lead) 350 is inserted through the catheter and into cardiac tissue 12 through the ablation created in the tissue to an appropriate depth determined by the surgeon. If desired, catheter 318 may include a depth stop to limit travel of the pacing lead into the cardiac tissue to prevent overpenetration. Thereafter, when appropriately configured with one or more electrical sensors, electrical signals may be detected from electrically active cardiac tissue using the electrode of the delivery catheter. An electronic mapping of the cardiac tissue may be prepared using the electrode of the delivery catheter. Once the pacemaker lead is inserted into the cardiac tissue, breaching either endocardium tissue outside of the septum, or at the septum, the pacemaker lead is anchored within the wall through the lead insertion opening created by the breach. It will be appreciated that the steps described above may be performed in a different order, varied, or some steps omitted entirely without departing from the scope of the present disclosure. For example only, catheter 318 may be connected to power source 348 at any point after it is at least partially inserted into the patient. Electronic sensing and mapping may be omitted if desired. Referring to Figs.4 and 10, the catheter is preferably designed with a pre-formed, three-dimensional curve at its distal end that allows it to naturally conform to the contours of the heart. This shape is important for directing the catheter tip into precise target sites within the heart, such as the right ventricular septum or the bundle of His, which are key areas for conduction system pacing. The pre-formed curve facilitates the catheter’s manoeuvrability through the complex structure of the heart, helping to ensure that the tip can be positioned accurately without excessive manipulation by the operator. Fig.10 shows catheter 318 inserted into the heart, with the pre-formed shape guiding tip 326 to the desired target site. The catheter’s ability to follow the heart’s anatomy reduces the need for manual adjustment and enhances the likelihood of successful lead placement. This design is particularly beneficial in procedures where precise positioning is critical to achieve effective pacing and minimize or avoid complications. Fig.10 specifically highlights the catheter’s use in targeting the right ventricular septum or the bundle of His, areas known for their importance in conduction system pacing. By accurately directing the catheter tip to these sites, the catheter design supports optimal lead placement for effective pacing therapy. In order that the present disclosure may be readily understood and put into practical effect, particular preferred embodiments will now be described by way of the following non-limiting example. Example Experimental Data A delivery catheter was developed featuring a platinum ring at the tip (approximately 2mm in length) on a 7F catheter sheath. This ring was connected to an RF generator, allowing delivery of low-energy radiofrequency (RF) pulses directly to the endocardium. The catheter was hollow, enabling the pacemaker lead to be delivered through the center immediately after RF energy application. This design helped maintain the catheter's position relative to the RF lesion, reducing the risk of dislodgement. Initial Experimental Findings In initial experiments: • deployment of the pacemaker lead was attempted without RF application. The lead became entangled, causing substantial delamination of the endocardium. • RF energy was then applied (3 seconds at 15W) before deploying the lead. The lead penetrated the tissue smoothly, with no entanglement. • Repeated tests confirmed that using RF energy significantly reduced the incidence of lead entanglement. Pilot Unipolar RF EndoBreach Study: Aims • To investigate the lesion properties from the RF EndoBreach catheter. • Modify RF power for 5 second delivery. • Depth, width, length measured. Methods • 3 ex-vivo hearts • 11 lesions per heart • 3 Different parameters o 10W @ 5 Seconds o 15W @ 5 Seconds o 20W @ 5 Seconds • Lesion Measures: o Depth o Width o Length Results ust ssu Lesion Width Lesion Depth Power Lesion Length (mm) (mm) ANOVA p-value (W) (mm) (95%CI) (95%CI) (95%CI) 10 4.8 (3.8 to 5.8) 4.0 (3.1 to 4.8) 0.60 (0.47 to 0.73) Length: 0.010 Epicardial Testing – Thicker tissue. • Epicardium is thicker and tougher than endocardium (represents more fibrotic heart) • Evaluated 5x insertions each: 10W @ 5s lesion and controls Progressive tiss All RF Breach successful deep implant, 1 control deep implant, 4 entangle or failure to penetrate (very high torque) The working hypothesis was that the RF energy alters the mechanical properties of the endocardium—by softening it—thereby allowing the lead to penetrate more easily without becoming entangled. The foregoing description is by way of example only, and may be varied considerably without departing from the scope of the present disclosure. For example only, various breaching means may be used to separate cardiac tissue, such as a mechanical mechanism (e.g., blade), thermal mechanism, ultrasound, and / or laser. Where the system includes an electrode, the electrode may be detachably attached to the catheter by means other than a fillet. For example only, the electrode may be attached to the catheter body by threaded engagement, snap-fit engagement, and / or magnetic engagement (where the magnetic field emitted is within an acceptable range given sensitive equipment being used). Referring now to Fig.9, if desired, a haemostasis device 452 may be added to the catheter. Fig.9 shows a haemostatic valve 454 and flush port 456. Fig.9 illustrates a perspective view of the delivery catheter, highlighting the integrated handle, electrical connection, and associated components used in pacemaker lead implantation. The handle of the catheter is preferably designed to provide ergonomic control and precise manipulation during the implantation procedure. The handle includes a mechanism that allows for easy maneuvering of the catheter within the heart, ensuring that the tip is accurately positioned at the target site. The design of the handle offers both comfort and control to the operator, facilitating the delicate adjustments necessary during the procedure. The features described with respect to one embodiment may be applied to other embodiments, or combined with or interchanged with the features of other embodiments, as appropriate, without departing from the scope of the present disclosure. The present disclosure in a preferred form provides the advantages of facilitating pacemaker lead placement to enhance a successful outcome, e.g., penetrating fully to a desired depth, for example, 9 to 10 mm to provide optimal pacemaker lead anchoring. Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of forms of the embodiments disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

What is claimed is:

1. A delivery catheter for delivering a pacemaker lead, comprising: a catheter body including: a distal end for insertion first into cardiac tissue; a proximal end opposite said distal end along a central longitudinal axis; and a central lumen from said proximal end to said distal end; an electrode at said distal end; and a conductor wire oriented along a length of said catheter body from said proximal end to said distal end, said conductor wire connecting said electrode to an energy source.

2. The catheter of claim 1, wherein said electrode extends beyond the distal end of said catheter body.

3. The catheter of either claim 1 or 2, wherein said electrode includes a curvilinear surface.

4. The catheter of any one of the above claims, wherein said electrode encircles a portion of said distal end of said catheter body.

5. The catheter of claim 4, wherein said electrode has a central longitudinal axis oriented transverse to the central longitudinal axis of said catheter body.

6. The catheter of any one of the above claims, further comprising a connector to connect said conductor wire to the energy source.

7. The catheter of claim 6, wherein said connector is a socket.

8. The catheter of any one of claims 1 to 5, wherein the delivery catheter is detachably connectable to the energy source.

9. The catheter of any one of the above claims, wherein a portion of said conductor wire encircles the central longitudinal axis of said catheter body.

10. The catheter of claim 1, wherein said electrode is external to said catheter body.

11. The catheter of any one of the above claims, wherein said wire is configured to deliver thermal energy.

12. The catheter of any one of the above claims, wherein said wire is configured to deliver radio frequency energy.

13. The catheter of any one of the above claims, wherein said distal end is configured to separate cardiac tissue without rotation.

14. The catheter of any one of the above claims, wherein said electrode is unipolar.

15. A method for implanting a pacemaker lead into a patient, comprising: inserting a delivery catheter into the patient, the delivery catheter including an electrode at a distal end thereof; breaching cardiac tissue with the electrode of the delivery catheter; and inserting the pacemaker lead through the delivery catheter and electrode into the patient.

16. The method of claim 15, further comprising detecting electrical signals from electrically active cardiac tissue using the electrode of the delivery catheter.

17. The method of either claim 15 or 16, further comprising obtaining an electronic mapping of the cardiac tissue using the electrode of the delivery catheter.

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