Coated Implantable Medical Device and Coating Method

Abstract

An intracardiac pacing system comprising a fixation element for fixing the intracardiac pacing system to body tissue is disclosed. The fixation element comprises a metallic material, and is at least partially coated with a metal-ion release inhibiting material. Also, a method for coating at least part of an intracardiac pacing system is disclosed.

Claims

1. An intracardiac pacing system comprising a fixation element for fixing the intracardiac pacing system to body tissue, wherein the fixation element comprises a metallic material, and wherein the fixation element is at least partially coated with a metal-ion release inhibiting material.

2. The system of claim 1, wherein the fixation element comprises a shape memory alloy.

3. The system of claim 2, wherein the fixation element comprises nitinol.

4. The system of claim 1, wherein the metal-ion release inhibiting material is a Ni-ion release inhibiting material.

5. The system of claim 1, wherein the metal-ion release inhibiting material is an amorphous material.

6. The system of claim 1, wherein the metal-ion release inhibiting material is selected from the group of: a-Si.sub.xC.sub.1-x:H, TiN, diamond-like carbon, and parylene.

7. The system of claim 1, wherein the fixation element comprises one or more tines.

8. The system of claim 1, further comprising a lead extension with a further fixation element for fixing the lead extension to body tissue, wherein the further fixation element comprises a metallic material, and wherein the further fixation element is at least partially coated with the metal-ion release inhibiting material.

9. The system of claim 1, wherein the metal-ion release inhibiting material has a thickness of 1 nm to 1000 nm.

10. A method for coating at least part of an intracardiac pacing system, comprising steps of: providing the intracardiac pacing system, wherein the intracardiac pacing system comprises a fixation element for fixing the intracardiac pacing system to body tissue, and wherein the fixation element comprises a metallic material, and depositing a metal-ion release inhibiting material on at least a portion of the fixation element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Following, exemplary embodiments are described with reference to figures. Here show:

[0026] FIG. 1 a first embodiment of an intracardiac pacing system, and

[0027] FIG. 2 a second embodiment of an intracardiac pacing system.

[0028] Same reference numerals are used for same components.

DETAILED DESCRIPTION

[0029] FIG. 1 shows an intracardiac pacing system 1 with a pacing electrode 2 and tines 3. The pacing electrode 2 is disposed on a lower end of the intracardiac pacing system. The tines 3 protrude from the lower end and form a tine array. After implantation of the intracardiac pacing system 1, the system is fixed in the heart (e.g. in the ventricle or in the atrium) by the tines 3 which penetrate heart tissue (e.g. the myocardium).

[0030] The tines 3 are used to anchor the intracardiac pacing system in the myocardium and ensure contact of the pacing electrode 2 with the tissue. The tines 3 are in permanent contact with tissue following implantation. The tines 3 are also in close proximity to the pacing electrode 2. Making the tines more biocompatible leads to less body rejection. This may result in a slower endo encapsulation rate, and/or a lower pacing threshold.

[0031] The tines 3 are made of nitinol and at least partially coated with a-Si.sub.xC.sub.1-x:H. In one embodiment, the tines 3 are completely coated with the a-SiC coating. Nitinol is known to elute Ni ions, which may cause harm in the human body. By applying the a-SiC coating on the surface of the tines 3, the amount of released Ni into the tissue and corresponding inflammatory reactions can be significantly reduced. By covering the surface of the tines 3 with the a-SiC coating, the immune system does not react as much to the intracardiac pacing system 1 (being a foreign object in the body) as it may do without the coating. The a-SiC coating has a thickness of 80-200 nm. The nitinol matrix of the base metal will be no longer in contact with body fluids and tissue.

[0032] The intracardiac pacing system may comprise a housing. In the housing, a battery and an electronic module may be arranged. The battery is configured to provide electrical energy to the components of the intracardiac pacing system, in particular to the electronic module and to the pacing electrode. The electronic module may comprise a processor and/or memory. The processor may be configured for sensing and/or pacing operation of the intracardiac pacing system. A second electrode (e.g. a ring electrode) may be arranged on the housing, e.g. at a proximal end of the housing.

[0033] In the embodiment shown in FIG. 2, the intracardiac pacing system 1 comprises a lead extension 4. At a distal end of the lead extension 4, further tines 5 are disposed. The further tines 5 are also made of nitinol and (partially or completely) coated with an a-SiC coating. In this embodiment, the main body of the intracardiac pacing system 1 may be anchored in the ventricle by the tines 3 and the lead extension may be anchored in the atrium by the further tines 5. The intracardiac pacing system 1 may be used in a VDD (ventricular pacing, dual chamber sensing, triggered and inhibited mode) and/or DDD (dual chamber pacing and sensing, triggered and inhibited mode) pacing embodiment.

[0034] Following, a procedure for coating the tines 3 and/or the further tines 5 with an a-SiC coating is described. The surface coating of the tines/further tines is produced by way of a PECVD (plasma enhanced chemical vapor deposition) process. As coating material, amorphous hydrogenated silicon carbide (a-Si.sub.xC.sub.1-x:H) is used. A suitable a-SiC coating can be obtained, if the supplied process gases of the PECVD process are 10% silane (SiH.sub.4) diluted with hydrogen as the silicon supply, and pure methane (CH.sub.4) for carbon supply alloying together with 0.1% of phosphine (PH.sub.3) also diluted with hydrogen. Suitable process parameters are:

TABLE-US-00001 pressure range: 0.02-1 mbar; gas composition: 50-80% methane, 100-0% silane, 0-2% phosphine; gas flow: 10-50 sccm silane; substrate tempera- 0-350 C. ture:

[0035] The features disclosed in the specification, the claims and the figures may be relevant for realizing embodiments either alone or in any combination with each other. It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof. Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points.

LIST OF REFERENCE NUMERALS

[0036] 1 intracardiac pacing system

[0037] 2 pacing electrode

[0038] 3 tines

[0039] 4 lead extension

[0040] 5 further tines