Patent Application
20210220609
This patent application claims the benefit of and priority to co-pending European Patent Application No. EP 20152121.8, filed on Jan. 16, 2020 in the European Patent Office, which is hereby incorporated by reference in its entirety.
The disclosure relates to a method for implanting a pressure sensor into the left atrium of a human heart. In addition, the disclosure relates to an implantable pressure sensor probe for measuring a pressure in the left atrium of a human heart, and to a catheter for implanting a pressure sensor probe into the left atrium of a human heart.
Such pressure sensors or pressure sensor probes, which measure a pressure in the left atrium, may be used, for example, to measure the filling pressure of the left heart in heart failure patients in order to optimise a drug therapy. Implantable pressure sensors for measuring pulmonary arterial pressure are known. However, these do not directly measure the pulmonary venous pressure, which is a decisive influencing variable for pulmonary congestion as a result of left heart failure, but instead measure a pressure in the pulmonary arterial system. The pulmonary arterial pressure follows the pulmonary venous pressure, but is also influenced at the same time by the transpulmonary gradient. It is not possible to clearly separate the two influences from each other, and therefore with this method a measurement inaccuracy remains with regard to the pulmonary venous pressure.
Transseptally implanted left atrial pressure sensors circumvent this disadvantage because they measure pulmonary venous pressure directly in the atrial diastole. The use of left atrial pressure sensors is known per se. For example, U.S. Pat. No. 8,016,764 describes the use of left atrial pressure sensors to determine ventricular dyssynchrony, depending on which pacemaker system or implantable cardioverter defibrillator (ICD) is controlled. U.S. Pat. No. 8,343,059 proposes to use a pressure sensor implanted in the left atrium to analyse a left atrial pressure and to perform a therapy depending on it.
Traditionally, left atrial pressure sensors are implanted through the atrial septum (i.e. transseptally) from the right atrium into the left atrium. However, such an implantation method is risky and is therefore reserved for experienced implanters. Complications with transseptal puncture have been reported in clinical trials (for example LAPTOP-HF). Furthermore, there is a risk that the pressure sensor will become overgrown with myocardium in the long-term, which may lead to a falsification of the sensor signal.
The present invention is directed toward overcoming one or more of the above-mentioned problems, though not necessarily limited to embodiments that do.
An object of the present invention is to overcome the presented disadvantages of known solutions in connection with implantable pressure sensors.
According to one aspect, a method for implanting a pressure sensor into the left atrium of a human heart is provided. Accordingly, the pressure sensor is inserted transvenously through the coronary sinus of the heart into the left atrium. This allows the pressure in the left atrium to be measured directly, but avoids a transseptal puncture when implanting the pressure sensor. Instead, the pressure sensor is implanted via the coronary sinus at low risk.
The proposed solution combines the advantages of a left atrial pressure sensor with the known technology of coronary sinus probes. For example, probes for cardiac resynchronisation therapy (CRT) that are implanted through the coronary sinus are known. However, conventional left ventricular CRT probes implanted through the coronary sinus do not have a pressure sensor that could be used to optimise the therapy of CRT patients.
For example, the pressure sensor may be mounted in a distal portion of a pressure sensor probe. In this case the pressure sensor probe may be formed, for example, according to a second aspect, which is explained in more detail below. The pressure sensor probe may be inserted into the coronary sinus via a suitable venous access, such as the subclavian vein. The coronary sinus runs through the left atrioventricular sulcus and thus shares a wall with the left atrium. By puncturing this wall, the pressure sensor may be permanently inserted into the left atrium at the distal portion of the pressure sensor probe.
Accordingly, the proposed implantation method according to one embodiment may comprise the following steps: providing an implantable pressure sensor probe comprising the pressure sensor, wherein the pressure sensor is arranged in a distal portion of the pressure sensor probe; puncturing the shared wall of the coronary sinus and the left atrium to create an opening in the wall; and transvenously implanting the pressure sensor probe into the coronary sinus in such a way that the distal portion with the pressure sensor projects through the opening into the left atrium.
For example, the pressure sensor may be inserted completely into the left atrium in this way in order to measure a filling pressure there. Preferably, the pressure sensor projects freely into the cavity of the left atrium so that myocardial cells are unable to grow over the pressure sensor.
During implantation, the coronary sinus (CS) is first probed with a suitable implantation tool. For example, a sheath of the type used for implanting CS electrodes of systems for cardiac resynchronisation therapy (CRT) is suitable for this. Advantageously, combinations of inner and outer catheters with a guide wire and dilator are used. The inner catheter may be bent at the distal end for puncturing the vessel wall in the left sulcus atrioventricularis, so that the opening of the distal end points towards the left atrium.
In order to assess the orientation of the tip of the catheter under fluoroscopy, it is useful to provide the tip of the catheter with one or more markers that are detectable by X-rays. For example, a cranial marker, a caudal marker and a posterior marker may be applied to the catheter. By rotating the catheter together with the markers, the correct position for the puncture may then be verified under fluoroscopy.
The shared wall between the coronary sinus and the left atrium may then be punctured for example using a puncture wire, and the dilator and finally the internal catheter may then be inserted. After removing the puncture wire and the dilator, the pressure sensor probe may be pushed through the implantation tool so that the distal portion of the pressure sensor probe with the pressure sensor protrudes into the left atrium. The implantation catheter may now be removed, and the implantation catheter may be slit and divided, for example as is common with CS systems.
The pressure sensor probe may be designed such that it anchors into the coronary sinus and the position of the pressure sensor in the left atrium remains stable. For example, the pressure sensor probe may have an anchoring portion for this purpose. The anchoring portion may comprise at least one element selected from the following group: barb, umbrella, plate, loop and flange.
According to an exemplary variant, to create the opening (i.e. the puncture)—similarly to a septal puncture—a puncture needle in a needle catheter is guided through the splinting guide lumen of a guide catheter to the posterior wall of the left atrium. Possible embodiments of a catheter usable as such a guide catheter are explained further below in connection with the third aspect. The puncture needle then punctures the posterior wall and the needle catheter is inserted into the left atrium. The puncture needle is then withdrawn completely and the pressure sensor arranged on the distal portion of the pressure sensor probe is inserted into the left atrium via the horizontal needle catheter. After fixation of the pressure sensor, the needle catheter is withdrawn.
In one embodiment, the pressure sensor is guided through a guide lumen formed in a catheter into the coronary sinus and then exits the guide lumen through a lateral exit opening. A catheter according to the third aspect may be used for this purpose, as will be discussed in more detail below. In line with this, for example, a catheter in the form of a specially adapted coronary sinus probe with stimulation electrodes for a CRT system may be used, which is provided with a guide lumen from a proximal end to just before a distal end. The guide lumen is large enough to accommodate the pressure sensor probe. In an exemplary embodiment, the coronary sinus probe tapers shortly before the distal end and has a lateral exit opening at this transition. Through the exit opening, the distal portion of the pressure sensor probe together with the pressure sensor may leave the coronary sinus probe and project through the puncture site into the left atrium.
The coronary sinus probe, similarly to the catheter described above, may be provided with markers so that the position of the exit opening may be adjusted under fluoroscopy in the direction of the left atrium. The coronary sinus probe may then be placed in the coronary sinus in such a way that the stimulation electrodes lie in a suitable venous vessel and the exit opening points in the direction of the left atrium. A puncture wire may then be used to puncture the shared wall between the coronary sinus and the left atrium and the pressure sensor probe may be inserted, after which the wire is removed. For example, the pressure sensor probe may be provided with a lumen for the puncture wire.
In another variant of the implantation method, a balloon of the catheter is filled in the coronary sinus to fix a position of the exit opening. For example, in an exemplary embodiment of that variant, a splint is used in the coronary sinus similarly to the coronary sinus probe described above, with the difference that no stimulation electrode is used, but instead a balloon catheter placed specifically for this purpose. The balloon catheter may have a balloon at its distal end that may be filled and deflated. Furthermore, as described above with reference to the coronary sinus probe, the balloon catheter may have a guide lumen with a lateral exit opening for the pressure sensor probe, the exit opening being located just before the distal end of the balloon catheter. The balloon catheter is advanced into the coronary sinus with the balloon deflated. The balloon is then filled, thus wedging the balloon catheter into the coronary sinus from the inside. This fixes the exit point relative to the wall between the coronary sinus and the left atrium in a position suitable for puncture. Immediately afterwards, the wall is punctured through the exit opening and the pressure sensor probe is pushed in. Lastly, the balloon is deflated again to release the blood flow in the venous system.
It is also within the scope of the disclosure that a proximal portion of the pressure sensor probe may be connected to an implanted sensing device designed to receive signals indicative of a pressure sensed by the pressure sensor in the left atrium. For example, a proximal end of the pressure sensor probe may leave the venous vascular system at a suitable location, for example in the subclavian vein, and may be connected to a preferably pectorally implanted unit which detects the pressure signals from the sensor, stores them if necessary, processes them, and sends them to a device located outside the body. This unit may be a special unit for measuring the pressure signals only. However, it may also be, for example, a one-, two- or three-chamber pacemaker or an implantable cardioverter defibrillator (ICD) that is set up for the connection of a pressure sensor probe.
According to a second aspect, an implantable pressure sensor probe for measuring a pressure in the left atrium of a human heart is disclosed. In this regard it is provided that a distal portion of the pressure sensor probe comprises a pressure sensor for sensing the pressure.
The distal portion of the pressure sensor probe may further comprise an anchoring portion for anchoring the distal portion in tissue.
The pressure sensor probe or pressure sensor may be used in the method disclosed herein. Accordingly, what has been explained above with respect to pressure sensor probes and pressure sensors in connection with the implantation method applies analogously to some embodiments of the pressure sensor probe or pressure sensor, and vice versa.
The anchoring portion may be used to anchor the pressure sensor probe in the tissue, for example in the implanted state, in such a way that the position of the pressure sensor in the left atrium remains stable. The anchoring portion may comprise at least one element selected from the following group: barb, umbrella, plate, loop and flange.
According to a refinement, the pressure sensor probe may also have at least one electrode, for example a stimulation electrode. For example, this may be an electrode (or plurality of electrodes) of an implantable cardioverter defibrillator (ICD) or an electrode for cardiac resynchronisation therapy (CRT).
In principle, the pressure sensor probe either may be designed as a stand-alone implant or may be integrated as an additional component in an implantable system. For example, the pressure sensor probe may be integrated into a coronary sinus probe of a CRT system (or another type of pacemaker system) or may be combined as an additional probe with single- or dual-chamber pacemakers or ICD systems. In combination with CRT systems, the pressure sensor signal obtained in this way may be used, for example, to optimize therapy. Single-, dual- or triple-chamber pacemakers or ICD systems may also be advantageously expanded in this way to include the possibility of left atrial pressure measurement. Such systems, which additionally comprise a pressure sensor probe, therefore also lie within the scope of the invention.
A third aspect relates to a catheter for implanting a pressure sensor probe into the left atrium of a human heart. The catheter comprises a catheter body in which a guide lumen is formed for receiving/guiding the pressure sensor probe. A distal portion of the catheter body has the following: a lateral exit opening for guiding a distal portion of the pressure sensor probe out of the guide lumen; and a marker detectable by X-rays to determine a location of the exit opening.
The catheter may be used in the method disclosed herein. Further, the catheter may be provided and designed for implanting a pressure sensor probe disclosed herein. Accordingly, what is described above with respect to pressure sensor probes and catheters applies analogously to some embodiments of the catheter or pressure sensor probe, and vice versa. Features and embodiments of the various aspects may be combined as desired.
For example, as described above in connection with the implantation method, a balloon may be arranged on the distal portion of the catheter body. In other words, the catheter may be designed as a balloon catheter. This makes it possible to wedge the balloon catheter in a suitable position from the inside in the coronary sinus, as explained above. For example, this allows the exit point to be fixed in a suitable position relative to the wall between the coronary sinus and the left atrium.
As already explained, the marker may be used to rotate the catheter under fluoroscopy in such a targeted manner that the exit opening points in the direction of the left atrium (and there more precisely to a point intended for puncturing). The marker may, for example, comprise a heavy metal that is impermeable to X-rays and therefore easily recognisable in fluoroscopy. In one variant, the marker is T-shaped. This makes it easy to read the orientation of the catheter body under fluoroscopy.
Additional features, aspects, objects, advantages, and possible applications of the present invention will become apparent from a study of the exemplary embodiments and examples described below, in combination with the Figures and the appended claims.
Further advantages and embodiments are described below with reference to the figures, in which:
In a first step S1, the method according to
In the embodiment according to
In a second step S2 of the exemplary embodiment of the implantation method according to
According to an exemplary variant, to create the opening P—similarly to a septal puncture—a puncture needle in a needle catheter is guided through the splinting guide lumen of a guide catheter to the posterior wall of the left atrium LA. Possible embodiments of a catheter 2 that may be used as such a guide catheter are shown in
The puncture needle then punctures the posterior wall and the needle catheter is inserted into the left atrium LA. The puncture needle is then withdrawn completely and the pressure sensor 12 arranged on the distal portion of the pressure sensor probe 1 is inserted into the left atrium LA via the horizontal needle catheter. After fixation of the pressure sensor 12, the needle catheter is withdrawn.
In a second step S2 of the exemplary embodiment of the implantation method according to
This is illustrated in more detail in
In
In the following, exemplary embodiments of a catheter 2 for implanting a pressure sensor probe 1 into the left atrium LA are explained with reference to
The catheter 2 shown in
In addition, a marker 24 is attached to the distal portion of the catheter body 20 and is detectable by X-rays in order to determine a position of the exit opening 22. In particular, the position of the outlet opening 22 in the direction of the left atrium LA may be adjusted under fluoroscopy by selective rotation of the catheter body 20. The marker 24 may, for example, comprise a heavy metal that is impermeable to X-rays and therefore easily recognisable by fluoroscopy.
In the shown variant, the marker 24 is T-shaped. This makes it easy to read an orientation of the catheter body 22 (and in particular a direction of the exit opening 22) under fluoroscopy. In this case, the marker 24 is in the form of an upright T on the same semicircle of the catheter body 20 as the exit opening 22. If the marker 24 shows an upright T in fluoroscopy, the exit opening 22 is directed ventrally (this corresponds to a correct rotation for access to the left atrium LA). On the other hand, if the T is inverted, the exit opening points dorsally and must be rotated 180°.
In the present exemplary embodiment, there is only a single marker 24 on the catheter body 20. Additional markers may in principle facilitate orientation.
The variation of the catheter 2 from
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 teaching. 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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20152121.8 | Jan 2020 | EP | regional |
