WO2019092031A1 - Instrument for cutting heart valves - Google Patents

Abstract

An instrument for cutting heart valves, comprising a first rod (2), which can be gripped at a proximal end (2a) and is provided at a distal end with a first, female head (3). The instrument (1) also comprises a second rod (4), which has, at a distal terminal portion, a second, male head (5), which forms a cutting edge (5a) with a transverse contour that corresponds to the contour of a mouth (3a) formed by the first head (3). The second rod (4) can move coaxially and reversibly with respect to the first rod (2) at least from a first limit configuration, in which the heads (3, 5) are mutually spaced apart, to a second limit configuration, in which the second head (5) is at least partially accommodated in the first head (3), for the cutting of at least one cusp of a heart valve to be replaced, following the preliminary introduction at least of the second head (5) into the valve and the subsequent transition from the first to the second configuration.

Description

INSTRUMENT FOR CUTTING HEART VALVES

The present invention relates to an instrument for cutting heart valves.

As is known, the human heart has four interconnected chambers, which are, in the order in which the blood passes through them, the right atrium, the right ventricle, the left atrium, and the left ventricle.

Between each atrium and the respective ventricle, and also between each ventricle and the corresponding downstream vessel (the pulmonary artery and the aorta), there are corresponding valves, the function of which is to control blood flow, mainly in order to prevent the blood from circulating in the direction opposite to the normal direction.

Although with some differences, all the valves indicated above are made up of two or three flaps of filamentous connective tissue, known as cusps, which, pushed by the variations in pressure inside the heart, are capable of opening or closing the respective orifice.

Occasionally, on such cusps an unwanted buildup of calcium is observed (usually transported by the blood), which gradually reduces their functionality, until surgery is required for the complete removal of the valve and its replacement with an artificial heart valve, so as to restore the correct functionality of the organ.

Moreover, such need arises as a consequence of various diseases, including genetically-determined diseases, which for example cause an incomplete closure or other malfunctions, with very serious consequences.

In all these cases therefore, the surgeon has to carry out a complex operation, with the chest open, first removing all the cusps of the valve to be replaced, and then proceeding to insert the replacement prosthesis.

To reduce the overall time of the operation, which constitutes a critical parameter that often determines the successful outcome, the focus of the surgeon and of the designers of operation devices and procedures has always been directed at the duration of the step of inserting the prosthesis, while less care is dedicated to the step of removing the original valve. In fact, usually such step (which in the event of large calcification buildups can take fifteen minutes or more) is carried out using ordinary scissors, with which the surgeon removes the cusps one by one, under direct vision.

This is evidently a very delicate activity, which requires time and which in any case requires the full concentration of the surgeon, which consumes some of the energy that he or she will need to dedicate to the step of actually inserting the prosthesis.

Moreover, immediately after having completed the cutting, the surgeon has to spend more time removing the fragments one by one, taking the maximum of care in order to prevent even one of them from remaining in the organ, from where it could enter the bloodstream and cause an embolism.

The aim of the present invention is to solve the above mentioned problems, by providing an instrument that ensures workable methods of cutting heart valves.

Within this aim, an object of the invention is to provide an instrument that makes it possible to cut and removing the cusps of a heart valve, in a short time.

Another object of the invention is to provide an instrument that enables a rapid and effective cutting of the cusps of a heart valve, without risks for the surrounding tissues during the cutting step.

Another object of the invention is to provide an instrument that makes it possible to rapidly and completely remove the fragments of the cut cusps of a heart valve.

Another object of the invention is to provide an instrument that ensures a high reliability of operation and which removes the cusps while preparing the organ for the best reception of the prosthetic device.

Another object of the invention is to provide an instrument that adopts an alternative technical and structural architecture to those of conventional instruments.

Another object of the invention is to provide an instrument that can be easily implemented using elements and materials that are readily available on the market.

Another object of the invention is to provide an instrument that has low costs and is safely applied.

This aim and these and other objects which will become better apparent hereinafter are achieved by an instrument according to claim 1.

Further characteristics and advantages of the invention will become better apparent from the description of a preferred, but not exclusive, embodiment of the instrument according to the invention, which is illustrated by way of non-limiting example in the accompanying drawings wherein:

Figure 1 is a side view of the instrument according to the invention, in the first limit configuration;

Figure 2 is a view from above of the instrument in Figure 1 , in the first limit configuration;

Figure 3 is a front elevation view of the instrument in Figure 1 , in the first limit configuration;

Figure 4 is a side view of the instrument in Figure 1, in a different mutual arrangement of the rods.

With reference to the figures, the reference numeral 1 generally designates an instrument designed for cutting heart valves. More precisely, in the preferred application, the instrument 1 is intended to be used by a heart surgeon to carry out in a practical and easy manner the cutting (and, as will be seen, also the removal) of the cusps of one of the heart valves, made necessary by their calcification (or other disease), and so enable their replacement with a prostheses.

The possibility is not ruled out however, while remaining within the scope of protection claimed herein, of using the instrument 1 according to the invention for the removal of other organs and/or flaps thereof, where the specific requirements indicate it and/or render it feasible.

According to the invention, the instrument 1 comprises a first rod 2, which can be gripped at a proximal end 2a thereof and which is provided at a distal end thereof (therefore at the opposite end to the proximal end 2a) with a first, female head 3.

Furthermore, the instrument 1 comprises a second rod 4, which has a second, male head 5 at a distal terminal portion thereof (therefore at the opposite end to the proximal end 2a of the first rod 2 and proximate to the distal end of the latter).

The second head 5 forms a cutting edge 5 a with a transverse contour that corresponds to the contour of a mouth 3 a formed by the first head 3. The phrase "transverse contour that corresponds to..." evidently means that the shapes of the respective contours (if observed in the axial direction, as in the view in Figure 3) practically coincide, just as the respective dimensions are practically identical (apart from a minimal difference).

The second rod 4 can move coaxially and reversibly with respect to the first rod 2, at least from a first limit configuration to a second limit configuration.

In the first limit configuration, shown in the accompanying Figures 1 to 3 in a possible (but non-limiting) practical implementation, the heads 3, 5 are mutually spaced apart (for example by a few centimeters).

In the second limit configuration (Figure 4 for example), the second head 5 is at least partially accommodated in the first head 3.

Thus, having earlier introduced at least the second head 5 into the heart valve to be removed, the subsequent transition from the first configuration to the second configuration, activated by the heart surgeon (or other user) determines the cutting of one or more cusps of the valve (and preferably of all the cusps). This is made possible by the cutting edge 5a, which, by virtue of its chosen transverse contour that corresponds to the contour of the mouth 3 a, skims the latter during the transition and, acting like a die cutter, carries out the desired cutting, thus already achieving the set aim.

It should be noted that such aim can also be achieved, entirely equivalently to the preferred solution described thus far, by providing the instrument 1 with a first, male head 3 and with a second, female head 5: this last embodiment is included in the inventive scope of the present invention and therefore no further details will be given as for the person skilled in the art it is a routine matter to deduce the specifications, which are effectively similar to those described herein for the preferred embodiment.

Preferably the cutting edge 5a (and therefore also the mouth 3a) has a circular transverse cross-section (or in any case a closed polygon/curve), so as to be able to cut all the cusps of the valve to be replaced with a single action.

In a particularly advantageous embodiment, which is also shown in the accompanying figures but which in any case does not limit the application of the invention, the first rod 2 is internally hollow, so as to define a duct for the slideable accommodation of a section of the second rod 4, adjacent to the distal terminal portion of the latter. So effectively, while the distal terminal portion of the second rod 4, where the second head 5 is located, protrudes externally from the first rod 2, an adjacent section of the second rod 4, which optionally can extend up until the respective proximal final portion (as in the accompanying figures), is accommodated in the first rod 2.

In a first implementation of the invention, the rods 2, 4 are rigid, and therefore do not have the possibility to modify their progression (straight or even curved, if the requirements indicate it) or other dimensional and shape parameters.

Moreover a rigid material is chosen solely for the first rod 2 and for the distal terminal portion of the second rod 4, thus giving the remaining part of the latter an elastic behavior for example.

Conveniently, in a different implementation, at least one segment of the first rod 2 is malleable (with the remaining part rigid, or even having different properties). It should be noted that a "malleable" segment evidently means that such segment is made of a plastically deformable material or in any case that it is made in such a way as to ensure such behavior, which is in contrast with elastic behavior, and which envisages maintaining the deformation (and thus the shape) obtained, when the stress that caused it is removed.

This enables the user (a heart surgeon or other user) to freely choose the shape structure and orientation of the first rod 2, and of the second rod 4, which to this end is chosen to be elastically deformable at least in a central portion which is intended to be slideably accommodated in the aforementioned malleable segment. Accordingly, the distal terminal portion of the second rod 4 will preferably be rigid, in order to allow the correct introduction of the second head 5 into the valve to be replaced.

The segment can be chosen in a central region of the first rod 2, or it can coincide with the proximal end 2 a, or extend from a central region up until the proximal end 2a or the like (even until it wholly or partially affects the distal portion).

However, the possibility is not ruled out of making the entire length of one or both of the rods 2, 4, or most of them, of malleable material.

In the preferred embodiment, at least the central portion of the second rod 4 (the portion accommodated in the malleable segment of the first rod 2) comprises a plurality of braided metal cables, preferably (but not exclusively) wrapped in a protective sheath. The sheath facilitates the sliding of the second rod 4 with respect to the first rod 2, even if the latter is variously folded or deformed, at its malleable segment.

In the embodiment illustrated in the accompanying figures, by way of non-limiting example, the first head 3 is shaped like an axially symmetrical cup (preferably with a circular cross- section), so as to define a receptacle 3b for the at least partial accommodation of the second head 5 (when it slides up until the second limit configuration, as in Figure 4).

Such receptacle 3b is therefore open outward right at the mouth 3a, effectively defined by an internal edge of the side wall of the first cup- shaped head 3. As can also be seen from the accompanying figures, the first head 3 has a transverse bulk that exceeds that of the second head 5.

This latter embodiment confers a further important benefit on the instrument 1 according to the invention: in fact, in this manner the maximum transverse bulk of the instrument 1 is given by the first head 3 while the element that carries out the cut, the cutting edge 5a, moves inside said bulk. This reduces or even cancels out the risk that, during the transition between the limit configurations of the second rod 4, the cutting edge 5 a could sever or in any case damage other surrounding anatomical tissues.

It should be noted moreover that the possibility exists of wrapping the first head 3 with a coaxial flange of non-traumatic material (or indeed made from the same material as the first head), so as to cover it externally and to effectively serve as a spacer, a centering device, and a separator of the cutting edge 5a from the surrounding tissues.

It should likewise be noted that giving the first head 3 a cup shape achieves another important result: when the second head 5 cuts the cusps of the valve and reaches the second limit configuration, it simultaneously closes the receptacle 3b. Thus, the receptacle becomes a kind of space for collecting the cut fragments of the cusps, which automatically end up inside it, thus guarding against the danger of their being dispersed outside, forcing the heart surgeon and his or her team to conduct a bothersome search, which would lengthen the time of the operation in a most undesirable manner.

Advantageously, and as can be seen from the accompanying figures, the cutting edge 5a is constituted by the undulated profile, directed toward the first head 3, of a blade wrapped around the longitudinal axis of the second rod 4 (which in any case coincides with the axis of the first rod 2).

While not ruling out the possibility of giving the cutting edge 5a other profiles, the choice of the undulated profile is of undoubted interest, as it ensures optimal modes of cutting, not least in light of the peculiar shape structure of the cusps of heart valves.

With further reference to the embodiment illustrated in the accompanying figures, the second head 5 comprises, at the opposite end to the cutting edge 5 a, a wedge 5b (conical or frustum- shaped) which tapers progressively outward.

The frustum shape structure ensures a non-traumatic insertion through the valve to be replaced; by contrast, a conical shape structure makes it possible to perforate tissues to be removed and in any case improves the capacity for penetration of the instrument 1 according to the invention.

The use of the wedge 5b, in any shape adopted, enables the facilitated insertion of the rods 2, 4 into the heart valve to be replaced and/or into the blood vessel leading to the valve.

In order to enable more convenient modes of using the instrument 1 according to the invention, it comprises a lever 6 for controlling the movement of the second rod 4 between the limit configurations. Such lever 6 is articulated to a contoured handle 7, which is integrally coupled to the proximal end 2a of the first rod 2. As can also be seen from the accompanying figures, such handle 7, in addition to having an ergonomic shape, effectively resembles a kind of "pistol", precisely in order to enable more practical modes of use by the user, who can in fact easily grasp it and handle it, for the removal of the valve to be replaced.

Conveniently, the instrument 1 according to the invention comprises a tube 8, which is applied externally to the first rod 2 (parallel to it) and which leads to a balloon 9 wrapped stably around the first head 3.

After sending pressurized fluid into the tube 8 (such fluid can be compressed air or the like), the balloon 9 can be temporarily inflated, thus facilitating the optimal anchoring of the first head 3 to the surrounding anatomical tissues. This evidently guards against the danger that, during the step of removing the valve, the instrument 1 (and the heads 3, 5 in particular) could move with respect to the ideal placement.

Moreover, the balloon 9 also contributes to keeping the surrounding tissues (particularly the coronary tissues) spaced apart from the cutting edge 5a, with evident benefits.

Advantageously, the instrument 1 can comprise a central channel, which is provided coaxially in the second head 5 and is open outward (on the end opposite that of the first head 3).

The channel can thus accommodate an auxiliary tool of the type of a video camera, a light source, a net for collecting loose fragments, and the like.

The use of a video camera makes it possible to display, including remotely, images of the blood vessel, of the heart cavity and of the heart valve to be replaced, before and/or during and/or after the operation of cutting and removal.

Thus it is possible to view the valve before it is reached by the heads 3, 5 (and therefore before proceeding with the cutting), so as to verify if there are abnormal occurrences of calcification on the cusps and/or on the valve, which would render their removal a complex matter; more generally the video camera ensures the visual control of structures that are otherwise not visible and makes the cutting more precise, thus minimizing the risks.

Accommodating a light source (which can be carried by the video camera) in turn enables better vision during the introduction of the instrument 1 (especially if the surgical operation is being carried out using minimally-invasive techniques).

Use of the instrument according to the invention is the following. As mentioned in the foregoing pages, a user (typically, but not exclusively, a heart surgeon) can use the instrument 1 for cutting and removing the cusps of a heart valve.

In order to achieve such result, the user grips the instrument 1 at the handle 7 and progressively inserts the shanks 2, 4 into the preselected blood vessel, until the valve and the cusps to be removed are reached. In order to be able to subsequently execute the cutting, the user needs to take care to place the instrument 1 so that the valve is interposed between the heads 3, 5 (arranged in the first limit configuration): the second head 5 must pass beyond the cusps (in doing this, the user is assisted by the wedge 5b) while the first head 3 is kept on the other side. Then, by acting on the lever 6, the user causes the passage of the second rod 4 toward the second limit configuration, with which, as seen, the cutting of the cusps is achieved, when the cutting edge 5 a skims the mouth 3 a.

Advantageously, the instrument 1 does not only perform the cutting of the valve (of the cusps) but also conveniently removes them, in that while the second rod 4 is being brought to the second limit configuration, the cut fragments fall automatically into the receptacle 3b, which is closed by the second head 5, partially accommodated in it. The user can thus extract the instrument 1, in order to obtain in an evidently convenient and rapid manner, the cutting and also the removal of the heart valve.

In more detail, by way of the instrument 1 it is possible to completely remove the heart valve with a single maneuver, with a (preferably) circular cutting, easily and without the dispersion of part of the cut tissue. This makes it possible to reduce, by several tens of minutes with respect to conventional methods, the overall time required for operations to replace heart valves with artificial heart valves.

Moreover, precisely the complete removal of the fragments prepares the organ to better receive the artificial heart valve, at the same time guarding against the danger of embolisms caused by free incorrectly- removed fragments of calcium (as could happen when operating according to conventional methods) and furthermore making it possible to keep the fragments for possible post-operative analysis and investigation.

It should be noted that the possibility of making even only a central segment, of the length of a few millimeters or centimeters, of a malleable material, enables the user to fold the first rod 2 (and the second rod 4 inside it) in infinite possible ways, by adapting the geometry of the instrument 1 to the specific requirements, in order to be able to best position the rods 2, 4, and insert their heads 3, 5 into the valve to be replaced, with greater ease. This evidently ensures maximum versatility to the invention, and even more convenient modes of use.

The increased bulk of the first head 3 makes it possible to carry out a rapid and effective cutting of the cusps, without any risk for the surrounding tissues in the cutting step. The balloon 9 also contributes to such functionality, and moreover ensures the stable locking in place.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.

In the embodiments illustrated, individual characteristics shown in relation to specific examples may in reality be substituted with other, different characteristics, existing in other embodiments.

In practice, the materials employed, as well as the dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. 102017000127620 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. An instrument for cutting heart valves, characterized in that it comprises a first rod (2), which can be gripped at a proximal end (2a) and is provided at a distal end with a first, female head (3), and a second rod (4), which has, at a distal terminal portion, a second, male head (5), which forms a cutting edge (5a) with a transverse contour that corresponds to the contour of a mouth (3a) formed by said first head (3), said second rod (4) being coaxially and reversibly movable with respect to said first rod (2) at least from a first limit configuration, in which said heads (3, 5) are mutually spaced apart, to a second limit configuration, in which said second head (5) is at least partially accommodated in said first head (3), for the cutting of at least one cusp of a heart valve to be replaced, following the preliminary introduction at least of said second head (5) into the valve and the subsequent transition from said first configuration to said second configuration.

2. The instrument according to claim 1, characterized in that said first rod (2) is internally hollow, in order to define a duct for the slideable accommodation of a portion of said second rod (4), which is adjacent to said distal terminal portion.

3. The instrument according to claim 2, characterized in that at least one segment of said first rod (2) is malleable, for the free choice of the shape and of the orientation of said first rod (2), and of said second rod (4), which is elastically deformable at least in a central portion which is designed to be slideably accommodated in said malleable segment.

4. The instrument according to claim 3, characterized in that at least said central portion of said second rod (4) comprises a plurality of braided metal cables, preferably wrapped in a protective sheath.

5. The instrument according to one or more of the preceding claims, characterized in that said first head (3) is shaped like an axially symmetrical cup, defining a receptacle (3b) for the at least partial accommodation of said second head (5), said receptacle (3b) being open outward at said mouth (3a), defined by an internal edge of the side wall of said first cup-shaped head (3), said first head (3) having a greater transverse bulk than that of said second head (5).

6. The instrument according to one or more of the preceding claims, characterized in that said cutting edge (5a) is constituted by the undulated profile, directed toward said first head (3), of a blade wrapped around the longitudinal axis of said second rod (4).

7. The instrument according to one or more of the preceding claims, characterized in that said second head (5) comprises, on the opposite side with respect to said cutting edge (5a), a wedge (5b) which progressively tapers outward, for the facilitated insertion of said rods (2, 4) into the heart valve to be replaced and/or into the blood vessel that leads to said valve.

8. The instrument according to one or more of the preceding claims, characterized in that it comprises a lever (6) for actuating the movement of said second rod (4) between said limit configurations, said lever (6) being articulated to a contoured handle (7) which is integrally coupled to said proximal end (2a) of said first rod (2).

9. The instrument according to one or more of the preceding claims, characterized in that it comprises a tube (8) which is applied externally to said first rod (2) and leads to a balloon (9) wrapped stably around said first head (3), as a consequence of the sending of pressurized fluid into said tube (8) said balloon (9) being temporarily inflatable for the optimum anchoring of said first head (3) to the surrounding anatomical tissues.

10. The instrument according to one or more of the preceding claims, characterized in that it comprises a central channel, which is provided coaxially in said second head (5) and is open outward, for the accommodation of an auxiliary tool of the type of a video camera, a light source, a net for collecting loose fragments, and the like.