WO2009063516A1

WO2009063516A1 - Positioning system for endovascular devices and the like

Info

Publication number: WO2009063516A1
Application number: PCT/IT2008/000502
Authority: WO
Inventors: Gianluigi Condorelli; Sergio Casciaro; Francesco Conversano
Original assignee: Consiglio Nazionale Delle Ricerche
Priority date: 2007-11-15
Filing date: 2008-07-25
Publication date: 2009-05-22
Also published as: ITTO20070824A1

Abstract

Positioning system for endovascular devices and the like comprising a catheter (A) having a possibly inflatable element (B), provided with ultrasonic probes (C,C',C'), a control algorithm and characterised in that at least one of said probes is arranged inside (C) the element (B) and at least one further probe is arranged outside the element (B), upstream (C) and/or downstream (C'), in order to allow an accurate spatial localisation - and in real time - of the inflatable element.

Description

Positioning system for endovascular devices and the like

DESCRIPTION An object of the present finding is a positioning system for endovascular devices and the like comprising a catheter having a possibly inflatable element, provided with ultrasonic probes, and a control algorithm in order to allow an accurate spatial localisation of the inflatable element and the subsequent monitoring of its localisation. In particular, the system allows manual, semi-automatic and automatic positioning of a possibly inflatable element, by monitoring, in real time, its position (mainly performed by means of special ultrasonic transducers) and possibly, depending on the degree of automation, by means of a linear actuation system which, according to the data obtained from ultrasonic tracking, and from pressure and physiological parameters in question, indicates and/or corrects in an iterative and automatic manner the position of the device and holds it at the desired position. According to the prior art, there is a limited number of examples of systems with ultrasonic sensors applied on the abovementioned catheters having a possibly inflatable element, but in most cases the main aim is to obtain an effective intravascular imaging for given diagnostic purposes, while there are no applications adapted for positioning the inflatable element, which on the contrary, is always performed manually possibly with the help of other imaging techniques (for example, X rays, transesophageal ultrasonography). Furthermore, each of these techniques has specific drawbacks, such as for example, the absorption of radiations regarding both the patient and the operators in case of X rays or, in case of transesophageal ultrasonography, the inapplicability in all cases involving the presence of air between the ultrasonography probe and the endovascular device in question (as it occurs for example in all interventions during which the heart is temporarily emptied of blood of which it is normally filled).

An example of use of positioning systems for endovascular devices and the like is observed in interventions for repairing or replacing the mitral valve with minimally invasive surgery techniques such as Port-Access, in which it is necessary to stop the blood flow towards the heart and empty the heart of the blood of which it is filled, in order to allow the surgeon the necessary and suitable visibility during mini-invasive surgery. In order to have a good visibility during the endoscopic performance of the intervention, a possibly inflatable element, such as a balloon fixed in proximity to the tip of a catheter, which is positioned manually by the anaesthetist, generally with the help of X rays or a transesophageal ultrasonography, in proximity to the entry of the cardiac cavity to stop the blood flow. For an effective performance of the intervention, the positioning of the balloon must be carried out in an extremely accurate manner and monitored constantly over the entire duration of the operation, in such a manner to avoid both the interruption of blood flow to the brain and possibly the flow of blood towards the interior of the heart. Proper positioning of the balloon, and above all monitoring it during the intervention, requires considerable attention by the surgeon and the anaesthetist, further complicating their intervention, thus consequently increasing the probability of making some mistake. Known to the prior art are systems for positioning endovascular devices or the like outlined in the following patents: United State patent US 2005/0222596 whose object is an intravascular catheter provided with an inflatable element, referred to as a balloon, with blades for facilitating the dilation of the blood vessels in zones affected by stenosis due to the presence of arterioschlerotic plaques. Furthermore, the catheter in question is provided with a transducer made up of ultrasonic sensors, whose purpose is to directly monitor the conditions of the point of intervention without requiring the use of two separate catheters for the dilation of the vessel and for evaluating the effectiveness of the performed intervention. The insertion of the catheter is always performed manually and requires the help of X rays with a contrast medium, for proper positioning. Another example of application is outlined in the United States patent application 5,190,046. The object of such application is a device comprising a catheter provided with a balloon and a ultrasonic transducer for imaging the wall of a cavity or vessel. The object of the finding is to obtain detailed images of the anatomical wall in question, for monitoring in real time the performance of some processes such as for example the removal of some calcific deposits in proximity to the aortic valve. Also in this embodiment, the insertion of the catheter is always performed manually and requires the help of another imaging technique; furthermore, the ultrasonic transducer, is not mounted integral with the main body of the catheter, but it is introduced subsequently, after the first balloon has reached the desired position and after it has been inflated in a manner to adhere to the wall in question.

The applications already known to the prior art, have the several drawbacks outlined hereinafter: the positioning of the device is always performed manually by an operator and requires the guidance of a separate imaging technique, and invasive in any case, (generally X rays with a contrast medium); present on the catheter is always one ultrasonic transducer, which thus allows monitoring only one section of the vessel at a time, with the consequent shortcomings when localising the accurate positioning of the balloon; furthermore, the arrangement of the ultrasonic transducer with respect to the catheter and the corresponding algorithms for processing signals are suitable for applications in which the ultrasonography image represents a final output, but they are not optimised in a manner such to use this data as input for an automatic, semi-automatic or manual positioning system; lastly, the geometry of the inflated balloon is conceived to facilitate the performance of specific tasks provided for (dilating an arterioschlerotic vessel, imaging), while it never offers specific solutions intended to optimise the effectiveness of the balloon when stopping the blood flow.

An object of the finding subject of the present invention is that of providing a positioning system for endovascular devices and the like capable of automatically detecting, in real time, the position of the possibly inflatable element, such as for example, a balloon mounted on the endovascular catheter for endoluminal occlusion or clamping in relation to anatomic references. The finding subject of the present invention solves the abovementioned technical problems in that being a positioning system for endovascular devices and the like it comprises a catheter with a possibly inflatable element, provided with ultrasonic probes, a control algorithm and characterised in that at least one of said probes is arranged inside the possibly inflatable element and at least one further probe is arranged outside the possibly inflatable element, upstream and/or downstream, in order to allow the accurate spatial localisation of the element itself.

The automatic detection of the system in the vascular system occurs in a direct manner and mainly through tracking based on the signals and ultrasonic images, and in an indirect manner by measuring other pressure and physiological parameters (internal pressure of the balloon, cardioplegia flow, longitudinal tension of the catheter, blood pressure and flow, etc.). Operating on some of these parameters and having the position based on the ultrasonic tracking as the direct reference, alongside data provided by various sensors integral with the catheter and distributed (physiological/non-physiological pressures and flows, temperatures, electrical activities, etc.) on or in the patient's body, it is possible to use an expert system capable of automatically positioning the device and capable of providing clear indications on how to possibly correct its positioning inside the vessel at any time, by means of a linear actuation system. Furthermore, the catheter can be provided, at the ends of the possibly inflated balloon, with suitable systems comprising telescopic micro-rods with a radial symmetry which, during the balloon swelling phase, limit its expansion in the axial direction, in such a manner to optimise the adherence against the wall of the vessel reducing the risk of occluding some ramifications of the vessel itself. These and other advantages shall be clear from the detailed description of the invention with specific reference to drawing 1/1 represented in which is an absolutely non-limiting example of a preferred embodiment of the present finding. Referring to fig. 1 of the abovementioned drawing, which shows a plan view of the positioning system for endovascular devices and the like according to the invention, the illustrated intravascular catheter A has a possibly inflatable balloon B, associated to 3 arrays of ultrasonic sensors C, C, C", arranged respectively upstream C, inside C and downstream C" of the balloon. The transducers C, C, C" are controlled through three independent lines D, D' and D" respectively, which are also used for conveying the signals received by the transducers towards the processing units (not shown in the figure). The processing unit, through a parallel processing of the data coming from the various arrays of sensors, converts this data into specific information regarding the position of the balloon, such information being suitably transferred to the interface system, expert or non-expert, which regulates the pressurisation of the possible inflatable balloon and the movement of the device integral with the catheter itself. In particular, figure 1 shows a possible application of the proposed invention adapted to occlude a vessel. As a matter of fact, the catheter A is found inside the aorta E, arranged in the section comprised between the coronary arteries F and F' and an arterial blood vessel arranged in proximity thereto G. Only after having reached the position indicated in figure 1, the balloon, previously deflated, was inflated by means of a pipe H and its expansion in the axial direction was limited by the telescopic rods system with radial symmetry I and I', also possibly actuated only after the balloon reached the preset positioning. In the illustrated configuration, the balloon is capable of preventing the flow of blood towards the heart, in such a manner to facilitate, for example, the performance of endoscopic interventions on the aortic valve L or on the mitral valve (not shown in the figure). Furthermore, the central pipe can be used for fluid and liquid flows containing for example medicines or other substances (cardioplegia, etc).

During the performance of the intervention, herein provided as an example, it is important that the balloon reasonably remains at the indicated position, that is without occluding the vessel G and also without getting too close to the coronary arteries F and F', in that the tip of the catheter M could damage the aortic valve L or occlude the cardioplegia flow towards the heart and the coronaries. Furthermore, it is of paramount importance that inside the balloon there constantly be the pressure required to make it adhere in a satisfactory manner against the wall of the vessel, in such a manner to effectively prevent the flow of blood towards the heart. In the present invention, all this can be provided in an automatic manner, due to the particular distribution of the ultrasonic transducers and of other possible sensors as well as due to the algorithm which processes the signals received from them and directly converts them into operative instructions for the balloon movement and pressurisation system. According to such information, the user can further decide to lower the degree of automaticity of the system itself up to turning the entire system semi-automatic or manual, also to meet the occurrence of particular emergency situations during the intraoperative phase.

As conceived, the system allows preventing conditions of extreme gravity which might put the patient's life at risk. As a matter of fact, during the performance of the intervention, should the balloon move "backwards", that is tend to occlude the vessel G, the transducer C" would be located at the vessel G before the balloon. The algorithm for analysing the image applied to the data provided by the transducer C" would thus immediately detect this unwanted movement and, still in real time, it would send - to the actuator - the instructions required to return the balloon back to the desired position. On the contrary, should the balloon move "forwards", thus risking moving the tip of the catheter M too close to the aortic valve L, the combined analysis of the radio frequency signals and the relative images received by the transducers C and C - also due to the use of the "expert systems" such as for example neural networks - would instantaneously identify the movement of the balloon towards the heart, sending - also in this case - the instructions required for the actuator to return the balloon back to the desired position. This algorithm for analysing radio frequency signals, always operating on the data coming from the transducers C and C, is also capable of detecting possible "loss of sealing" of the balloon, that is the possible flow of blood towards the heart. In the latter case, the algorithm would produce an input for the pressurisation system, which would end up suitably increasing the pressure inside the balloon, in such a manner to optimise the adherence against the walls of the vessel. All the previous operations can be performed under complete manual or semi- manual assisted conditions.

A further possible application of the invention proposed, characterised by the positioning of an endovascular device in a fluid can be represented, for example, by the percutaneous delivery of artificial heart valves, or by neurosurgical interventions for the removal of stenosis, or lastly, by positioning catheters in patients subjected to dialysis o having serious nutritional deficits.

The advantages of the positioning system, subject of the present invention are clear: the system guarantees, in a reliable and unique manner, the detection of the spatial position of the device, with good dynamic performances, silence, accuracy at positioning and quickness at performing the movement as well as the reduction of probability for the surgeon and/or anaesthetist to make mistakes. Thus, the present invention regards the capacity to automatically detect, in real time, the position of the device mounted on the endovascular catheter both for endoluminal occlusion or clamping in relation to anatomic references and only for monitoring or for other localised treatments without occluding the vase. In particular, said system allows the easiest initial positioning and subsequent monitoring of the position inside the vessel of any suitably equipped intravascular device. Furthermore, such configuration allows its possible interfacing with an expert system provided with actuators for moving and positioning when performing specific surgery interventions, such as for example interventions on the heart valves and operations requiring cardiopulmonary or coronary bypass. The automatic detection of the position in the vascular system occurs in a direct manner and mainly through the tracking based on signals and ultrasonic images as well as in an indirect manner by measuring other pressures and physiological parameters (internal pressure of the balloon, cardioplegia flow, longitudinal tension of the catheter, blood pressure and flow etc.). Operating on some of these parameters and having the position based on the ultrasonic tracking as the direct reference, it is possible to use an expert system capable of automatically positioning the device or capable of providing clear indications on how to move it suitably inside the vessel.

The main field of application of the present invention regards surgical and endoscopic operations of the endovascular type which require a correct positioning and monitoring, in real time, of the position of the endovascular/catheter device in question with respect to the anatomical markers. This, even without requiring the interruption of flows inside the vessel or pipe. As a matter of fact, the present invention could also be implemented allowing the free flow of fluids in case of a device in which for example the balloon is partially expanded or nonexistent and the telescopic rods used for positioning and anchoring against the vessel/pipe wall of the device mounted on the catheter itself is of the non-occlusive type.

Exemplifying applications can be of the percutaneous delivery of artificial heart valves, neurosurgical interventions for the removal of stenosis, positioning catheters in patients subjected to dialysis o having serious nutritional deficits, etc.

An example can be an intervention for repairing or replacing the mitral valve, performed with a mini-invasive approach. As a matter of fact, in such operations, it is necessary to stop the flow of blood towards the heart over the entire operation. The system proposed can also be effectively used in any surgical intervention in cases where the positioning of a device in a vessel with or without the flow of a fluid must be guaranteed, an example of the application being the occlusion and/or or sealing of a pipe of a "piping" system using a general fluid. The system is made up of all or some of the following parts: an intravascular catheter, a possibly inflatable balloon, with or without removable rods for controlling its expansion in the axial direction, and provided with 2 or 3 miniaturised ultrasonic transducers mounted on the catheter.

An algorithm for processing, in real time, the signals coming from the ultrasonic transducers and the corresponding images, intended for determining the position of the device through specific applications of signal processing, image processing and also neural networks. A "ball-screw" linear actuator for the automatic movement of the device and regulation of the pressure therein according to the indications deriving from the ultrasonic tracking or from other various sensors distributed in or on the patient's body (pressures, flows, temperatures, electric activities, etc).

A "control loop" system to allow recursive interaction between the output of the algorithm and the movement system and possible pressurisation of the device.

Claims

1) Positioning system for endovascular devices and the like comprising a catheter (A) having a possibly inflatable element (B), provided with ultrasonic probes (C,C',C"), a control algorithm and characterised in that at least one of said probes is arranged inside (C) the element (B) and at least one further probe is arranged outside the element (B), upstream (C) and/or downstream (C"), in order to allow an accurate spatial localisation - and in real time - of the catheter and/or the possibly inflated element.

2) The system according to claim 1 is characterised in that the pressure, inside the possibly inflatable element during the occlusion, is such to make it adhere against the walls of the vessel or pipe.

3) The system according to claim 1 is characterised in that the pressure, inside the possibly inflatable element during the positioning and/or stationing, is such not to obstruct the flow into the vessel or pipe. 4) The system according to claim 2 o 3 further comprises a system for monitoring pressures, flows, temperatures, electric and electromagnetic activities, physiological parameters and spatial tracking of another type, made up of a plurality of sensors both on board and outside the catheter (A). 5) The system according to claim 4 further comprises an actuator system for the automatic movement of the possibly inflatable element (B) and the regulation of the pressure therein. 6) The system according to the preceding claims comprises an external system and a suitable man-machine interface displaying - in real time - the information required.

7) The system according to the preceding claims, is characterised in that the ultrasonic probes (C,C',C") are three and each of them is controlled through an independent line (D, D', D")

8) The system according to the preceding claims is characterised in that said control algorithm processes radio frequency signals and ultrasonography images in greyscale. 9) The system according to the preceding claims is possibly characterised by removable telescopic rods (I) with a radial symmetry for anchorage against the walls of the vase or pipe and also for controlling the expansion of the inflatable element (B) in the axial direction. 10) The system according to claim 1 is characterised in that said catheter comprises a central pipe (H) used for transporting fluids and liquids.

11) Method for positioning an endo vascular system or the like according to one of the preceding claims characterised in that the insertion of the system into a vase or another pipe can be performed in an automatic manner by means of the automatic detection and monitoring system with reference to anatomical markers, and a method for positioning a monitoring system and a linear actuation system or in a manual or automatic manner .

12) Use of an endovascular system or the like according to one of claims 1 - 10 in the field of medicine for positioning devices adapted both for temporary interruption of various flows, such as flow of blood into specific vessels in question, flow of faeces and the like into an intestinal tract, flow of air in the respiratory tract, and again, flow of bolus and the like into the oesophagus, and for monitoring or localised treatment as well as for any other endovascular procedure guided by ultrasonic systems integral with the catheter itself.

13) Use of a system according to one of claims 1 - 10 for hydraulic systems.