Cryoprobe for minimally invasive cardiac ablation with functional tip

Abstract

The cryoprobe for minimally invasive cardiac ablation with a functional tip according to the invention comprises a handle (5) and a first tip (1) with a cooling system for destroying tissue by freezing the tissue and at least one functional tip (2). Wherein the functional tip (2) is movable relative to the first tip and has at its end (4) at least a temperature measurement system (6) for the tissue to be destroyed by the first tip. The first tip in turn is mounted in the handle (5) provided with at least one button (3) for controlling the functional tip. Both the first tip and the at least one functional tip have a portion that is susceptible to plastic deformation. The cryoprobe according to the invention is characterized in that the at least one functional tip has a central portion that is susceptible to plastic deformation and a rigid portion at its end, and the first tip has at its end a portion that is susceptible to plastic deformation, while the remainder of the first tip is rigid. The invention also relates to a method for controlling the cryoprobe.

Description

Technical Field

[0001] The objective of this invention is to develop a cryoprobe with a functional tip for minimally invasive cardiac ablation, used to control ablation parameters outside the tissue. Background Technology

[0002] Documents US20110087205A1 and US20140200567A1 disclose a system, apparatus, and method for ablating targeted tissue adjacent to a patient's pulmonary veins by cutting. The ablation apparatus has a hinge comprising a cam assembly, a movable arm, a movable jaw, and a lower jaw. Control of the jaw is performed via a handle held in one hand. The jaw is equipped with sensors and elements for transmitting the energy required for tissue ablation. The tool described in the documents has a rigid working tip and rigid jaws, which cannot be shaped and adjusted to the desired shape during the procedure. This reduces the accuracy of temperature measurements and expands the ablation area, which is undesirable for adjacent tissue.

[0003] Document US20200000511A1 discloses a cryoprobe for cardiac ablation, comprising a handle, a control button, and two tips, one of which is movable relative to the other. The tips have rigid portions and flexible portions capable of conforming to the shape of the tissue. The tips disclosed in this document have a predetermined shape; they are flexible and rotatable. Ablation is performed simultaneously on both sides of the cardiac tissue to shorten procedure time. The tool described in the document has no sensors and does not measure the temperature of the tissue. During ablation, more cells are frozen than needed.

[0004] Document CN209253102U discloses a scheme similar to those disclosed in previously discussed documents. This includes a cryoprobe for cardiac ablation having two rigid tips: a cooling tip introduced into the tissue and a measuring tip applied to the outside of the tissue. Because the tips are rigid, they cannot be shaped during the procedure. This results in freezing unnecessary portions of the tissue or additional cutting within the tissue if reaching the desired ablation site is obstructed. This makes ablation performed by this device highly invasive.

[0005] The purpose of this invention is to provide a cryoprobe that does not have the aforementioned drawbacks, for use in performing precise ablation in the shortest possible time, so as to reduce damage to tissues that are not ablated. Summary of the Invention

[0006] Therefore, the object of this disclosure is to provide a cryoprobe capable of shortening surgical time. A cryoprobe for minimally invasive cardiac ablation with a functional tip according to this disclosure includes a handle, a first tip having a cooling system for destroying tissue by freezing the tissue, and at least one functional tip. The functional tip is movable relative to the first tip and has at least one temperature measuring system at its end for the tissue destroyed by the first tip. The first tip is mounted in a handle equipped with at least one button for controlling the functional tip. Both the first tip and the at least one functional tip have portions that are easily deformable. The cryoprobe according to this aspect is characterized in that at least one functional tip has a central portion that is easily deformable and a rigid portion at its end, and the first tip has a portion that is easily deformable at its end, the remainder of the first tip being rigid.

[0007] Preferably, the functional tip is hingedly attached to the first tip.

[0008] Preferably, the functional tip is permanently attached to the first tip by an elastic element.

[0009] Preferably, the functional tip is configured and adjusted to provide control using a button of a lever mechanism.

[0010] Preferably, the functional tip is configured and adjusted to provide control via a button on a rotating mechanism.

[0011] Preferably, the functional tip is configured and adjusted to provide control via a button on the tensioning mechanism.

[0012] Preferably, the functional tip is configured and adjusted to provide control by using a button on an electric actuator.

[0013] Preferably, the functional tip is configured and adjusted to provide control by using a button on the pneumatic actuator.

[0014] Preferably, it has a controller for the movement of the tip of the automatic or semi-automatic control function.

[0015] Preferably, it has an elastic element for pressing the functional tip in the direction toward the first tip.

[0016] Preferably, the first tip has a system for heating the surface of the first tip to shorten the time required to thaw the first tip from frozen tissue.

[0017] Preferably, the temperature measurement system for tissue includes thermocouples and / or semiconductor sensors.

[0018] The present invention also includes a method for controlling the cryopreservation probe, characterized by comprising the following steps:

[0019] a) Place the previously shaped first tip inside the tissue;

[0020] b) Activate the system for destroying tissue, continuously destroying tissue of a given thickness for a predetermined time;

[0021] c) Apply the end of the previously formed movable functional tip to the location where the first tip destroys the tissue;

[0022] d) Measure the physical quantities of the damaged tissue;

[0023] e) The detection indicates an excessively critical value of the physical quantity that causes tissue damage;

[0024] f) Pull the end away from the site of tissue damage;

[0025] g) Discontinue the use of systems that damage the organization;

[0026] h) Remove the first tip from the inside of the tissue.

[0027] Preferably, it uses a cryogenic probe with a controller for moving the tip of the probe for automatic or semi-automatic control functions, while automatically performing steps f) and / or g). Attached Figure Description

[0028] The invention will now be given with reference to the accompanying drawings, in which:

[0029] Figure 1 This is a side view of the tip of the cryoprobe.

[0030] Figure 2 This is an isometric view of the cryoprobe.

[0031] Figure 3 This is a schematic diagram of the mechanism by which the elastic element 7 presses the functional tip 2. Detailed Implementation

[0032] In cryoablation, negative temperatures are used to precisely neutralize tissue debris that causes electrical impulses to misconduct in the heart. Cryoablation is most widely used in eliminating the cause of atrial fibrillation. To kill the cells, the tissue temperature should be lowered to below -40 degrees Celsius. In this therapy, the effectiveness of cryoablation can reach as high as 80%.

[0033] If the cardiac tissue is completely frozen, cryoablation is effective. If the cardiac wall is not completely frozen and permanent cell necrosis is not caused, conductive bridges may form within the cells instead of eliminating atrial fibrillation, which could further exacerbate the atrial fibrillation. To eliminate the uncertainty associated with whether the cardiac wall has been completely frozen, it has been noted that active temperature measurements need to be designed simultaneously on both sides of the frozen tissue.

[0034] A crucial factor in cryoablation is measuring pericardial temperature during the process. Measuring the temperature solely at the cryoprobe may be insufficient, for example, due to inadequate contact between the cryoprobe and the cardiac tissue. In cases of insufficient contact, the temperature measured at the cryoprobe may be sufficient to kill cells, while the temperature outside the heart may not drop below the cell necrosis temperature, thus failing to induce cell death.

[0035] In a preferred embodiment, the device comprises a cryoprobe having a handle 5 and a first tip 1 having a cooling system for destroying tissue by freezing it. The system utilizes the energy of a liquid gas flowing within the tip 1, preferably nitrogen, helium, or hydrogen. Furthermore, the cryoprobe has a movable functional tip 2, which is movable relative to the tip 1. At its end 4, it has a temperature measuring system 6 in the form of a thermometer. The tip 2 is pivotally and hingedly attached to the tip 1, which has a handle 5 with a button 3 for controlling cooling and the movable tip 2. The temperature measuring system 6 performs a measurement of a physical quantity, based on which the tissue temperature is determined. Depending on the temperature measurement method employed, measurements may include: voltage at the contact of two different metals, changes in component resistance, changes in semiconductor connector parameters, and body thermal radiation parameters, such as pyrometers or color-changing visual thermometers.

[0036] In a preferred embodiment, the temperature measurement system 6 comprises thermocouples, such as type K thermocouples. System 6 measures the voltage of the thermocouple connector. For living tissue at a temperature of approximately 36°C, the type K thermocouple receives a connector voltage of approximately 16.5 mV; for a temperature of -80°C, which is the ablation temperature of the tissue in this embodiment, it receives a connector voltage of approximately -20 mV. Other types of thermocouples can be used, where their voltage and temperature characteristics may differ and may depend on the type, composition, and size of the connector.

[0037] In another preferred embodiment, a thermistor is used as system 6, i.e., a resistor with variable resistance and temperature characteristics. The physical quantity measured is resistance. The resistance of the thermistor is normalized for various temperatures. For the ablation temperature of -80°C in the preferred embodiment, the resistance of the platinum thermistor Pt100 is 68.33Ω, and for the living tissue temperature of 36°C, the resistance is approximately 112Ω.

[0038] In another embodiment, a semiconductor thermometer is used as system 6, preferably a system with a Zener diode. The measured quantity is the diode breakdown voltage, which is proportional to the connector temperature and is approximately 10 mV / K, or -3.4 V in a preferred embodiment at a temperature of 25°C. Zener diodes are known to have different breakdown voltage values ​​ranging from 1.2 V to 200 V, and the ratio of connector temperature to breakdown voltage value varies.

[0039] An alternative embodiment measures tissue radiation energy using a graded optical system and detector. This measurement uses a near-infrared detector in the 800-1200 nm wavelength range.

[0040] Both tips have readily malleable portions. Knowing the shape of the tissue to be ablated, the operator can shape the malleable portions of the tips as needed. Tip 1 is shaped at its end to replicate the internal shape of the frozen tissue. The malleable end of tip 1 is made of a readily malleable material, preferably an alloy of aluminum or copper. In another preferred embodiment, the malleable end of tip 1 is made of a less malleable material, such as steel, but appropriately weakened, for example by a series of cuts, or shaped as a spring, a thin mantle, a strip folded into a tube, or a flexible bellows. The central portion of the functional tip 2 is shaped such that its central portion bypasses the outer portion of the tissue not being ablated and any possible obstacles on the path to the ablation site, while providing mechanical contact between the rigid end of the functional tip 2 and the tissue being ablated from the outside. This separable and distinct shaping of the tips allows for a certain degree of mechanical contact between the end of tip 1 and the tissue frozen from the inside, which increases the accuracy of ablation and maximizes the transfer of energy to the frozen tissue. Simultaneously, it provides precise contact between the end 4 of the functional tip 2 and the location of the frozen tissue, as well as accurate measurement of that tissue. This shaping of the functional tip 2 allows for minimal contact with the tissue, and discrete temperature measurements. Because the tip does not contact tissue that is not being ablated, which has a considerably high temperature, the measurements are more accurate and faster. Therefore, the processing of frozen tissue can be completed much faster compared to using a rigid arm that contacts both ablated and non-ablated tissue for measurement.

[0041] The speed and accuracy of the measurements allow for shorter tissue cooling times and the diffusion of low temperatures beyond the ablation zone to areas where tissue damage is unnecessary. For tissues not subjected to ablation, shorter procedure times are advantageous.

[0042] The functional tip 2 is malleable and can be positioned anywhere relative to the tip 1 of the freezing part—the freezing probe. Malleability means that it can change its shape and maintain that shape.

[0043] In a preferred embodiment, an elastic element 7, such as a metal spring, is placed in the mechanism, and it presses the measuring tip against the tissue with a constant force.

[0044] In another preferred embodiment, the functional tip 2 is attached by a resilient element rather than a hinge.

[0045] Control of the functional tip 2 is achieved through a lever, rotation, or tensioning mechanism. In another preferred embodiment, it can be controlled by an electric actuator, such as an electric motor or electromagnet, or by a pneumatic actuator, such as a cylinder.

[0046] Use button 3 to manually or automatically control the tip and ablation process. In manual control, the operator must know the thickness and type of the tissue to be ablated and determine or calculate the time required for ablation, i.e., cooling a certain volume of cells to a sufficiently low temperature using a coolant at a sufficiently low temperature. This type of calculation is known to the person performing the ablation.

[0047] In a preferred embodiment, the cryoprobe has an additional system for heating the frozen portion of tip 1. After ablation is complete, tip 1 may freeze to the tissue and become impossible to remove, or attempting to remove it would damage the frozen tissue. Activating the heating element when the operator completes ablation heats the surface of tip 1 and thaws it from the tissue, allowing for safe removal of the tool.

[0048] In a preferred embodiment, the cryoprobe has a controller that controls the movement of the actuator of the functional tip 2. This control can be automatic or semi-automatic. Semi-automatic action causes the operator to pull the functional tip 2 toward the tissue, while automatic action activates the pulling mechanism.

[0049] The automated action, where the controller performs the closing and opening movements, means that after the ablation process begins, the controller measures its time, and at a predetermined or calculated time (after which the tissue is expected to be nearly completely frozen), it pulls the functional tip 2 to the freezing position, performs the measurement, and waits for the desired temperature to be reached. Once the desired temperature of the tissue is reached—the controller pulls the functional tip 2 away. In an alternative embodiment, cooling is stopped after the functional tip 2 is pulled away, and then heating of the cooling tip 1 is activated. The cooling tip 1 heats up faster than the frozen tissue, so it can be safely thawed and the tool is ready to be removed from the tissue. Furthermore, the automated action reduces ablation time but requires input of data related to the frozen tissue and the type of coolant.

[0050] The parameters for both manual and automated ablation are set by those skilled in the art prior to the procedure using known experience, mathematical models, and experimental data.

[0051] Preferred embodiments involve the ablation of myocardial tissue. Alternatively, these may be other tissues or cell populations.

Claims

1. A cryoprobe with a functional tip for minimally invasive cardiac ablation, comprising: Handle (5), It has a first tip (1) for a cooling system used to destroy tissue by freezing tissue and At least one functional tip (2), The functional tip (2) is movable relative to the first tip (1) and has at least one temperature measurement system (6) for tissue destroyed by the first tip (1) at its end (4), while the first tip (1) is mounted in the handle (5) which is equipped with at least one button (3) for controlling the functional tip (2), both the first tip (1) and the at least one functional tip (2) having plastically deformable portions, characterized in that the at least one functional tip (2) has a plastically deformable central portion and a rigid portion at its end, the central portion of the functional tip (2) being shaped such that its central portion bypasses the outer portion of the tissue not being ablated and any possible obstacles on the path to the ablation location, while providing mechanical contact between the rigid end of the functional tip (2) and the tissue being ablated from the outside of the functional tip (2), and the first tip (1) having a plastically deformable portion at its end shaped to replicate the internal shape of the frozen tissue, and the remainder of the first tip (1) being rigid.

2. The cryoprobe according to claim 1, characterized in that, The functional tip (2) is hingedly attached to the first tip (1).

3. The cryoprobe according to claim 1, characterized in that, The functional tip (2) is permanently attached to the first tip (1) by means of an elastic element (7).

4. The cryopreservation probe according to claim 1, 2, or 3, characterized in that, The functional tip (2) is configured and adjusted to provide control by using a button (3) of a lever mechanism.

5. The cryogenic probe according to claim 1, 2, or 3, characterized in that, The functional tip (2) is configured and adjusted to provide control by using a button (3) of a rotating mechanism.

6. The cryopreservation probe according to claim 1, 2, or 3, characterized in that, The functional tip (2) is configured and adjusted to provide control by using the button (3) of the tensioning mechanism.

7. The cryopreservation probe according to claim 1, 2, or 3, characterized in that, The functional tip (2) is configured and adjusted to provide control by using the button (3) of the electric actuator.

8. The cryoprobe according to claim 1, 2 or 3, characterized in that, The functional tip (2) is configured and adjusted to provide control by using the button (3) of the pneumatic actuator.

9. The cryoprobe according to claim 7, characterized in that, The cryoprobe has a controller for automatically or semi-automatically controlling the movement of the functional tip (2).

10. The cryoprobe according to claim 8, characterized in that, The cryoprobe has a controller for automatically or semi-automatically controlling the movement of the functional tip (2).

11. The cryogenic probe according to any one of claims 1 to 3, characterized in that, The cryoprobe has an elastic element (7) for pressing the functional tip in a direction toward the first tip.

12. The cryopreservation probe according to any one of claims 1 to 3, characterized in that, The first tip (1) has a system for heating the surface of the first tip (1) to shorten the time for thawing the first tip (1) from frozen tissue.

13. The cryogenic probe according to any one of claims 1 to 3, characterized in that, The temperature measurement system (6) for use in an organization includes thermocouples and / or semiconductor sensors.

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