The present invention generally relates to devices and methods for removing acute blockages from blood vessels during intravascular medical treatments. More specifically, the present disclosure relates to clot retrieval devices including a funnel aspiration catheter.
Clot retrieval aspiration catheters and devices are used in mechanical thrombectomy for endovascular intervention, often in cases where patients are suffering from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Accessing the neurovascular bed in particular is challenging with conventional technology, as the target vessels are small in diameter, remote relative to the site of insertion, and highly tortuous. Traditional devices are often either too large in profile, lack the deliverability and flexibility needed to navigate particularly tortuous vessels, or are ineffective at removing a clot when delivered to the target site.
Conventional clot retrieval catheters suffer from a number of drawbacks. First, the diameters of catheters themselves must be small enough to avoid causing significant discomfort to the patient. The retrieval catheter must also be sufficiently flexible to navigate the vasculature and endure high strains, while also having the axial stiffness to offer smooth advancement along the route. Once at the target site, typical objects to be retrieved from the body are substantially larger in size than the catheter tip, making it more difficult to retrieve objects into the tip. For example, firm, fibrin-rich clots can often be difficult to extract as they can become lodged in the tip of traditional fixed-mouth catheters. Additionally, this lodging can cause softer portions to shear away from the firmer regions of the clot.
Small diameters and fixed tip sizes are also less efficient at directing the aspiration necessary to remove blood and thrombus material during the procedure. The suction must be strong enough such that any fragmentation that may occur as a result of aspiration or the use of a mechanical thrombectomy device can be held stationary so that fragments cannot migrate and occlude distal vessels. However, when aspirating with a fixed-mouth catheter, a significant portion of the aspiration flow ends up coming from vessel fluid proximal to the tip of the catheter, where there is no clot, because the diameter of the funnel catheter is smaller than that of the vessel. This significantly reduces aspiration efficiency, lowering the success rate of clot removal.
Additionally, conventional clot retrieval catheters are not always successful in fully ingesting a clot. In such cases, the clot can become “corked” or stuck in the tip of the catheter, requiring a physician to have to remove the catheter from the target site in order to retrieve the clot from the patient. During removal of the catheter, the portion of the clot remaining outside of the catheter tip can break off, becoming “uncorked” during retraction, and can go back downstream re-blocking the blood vessel. Re-gaining access to the treatment site can then be challenging.
Any catheter design attempting to overcome these challenges would need to be able to fully ingest a clot at a treatment site and aspirate the clot through the catheter while ensuring the clot, or pieces of the clot, would not become “uncorked” from the catheter tip.
The present design is aimed at providing an improved retrieval catheter which addresses the above-stated deficiencies.
Example systems and methods of treatment are presented herein which generally involve positioning a funnel aspiration catheter within a blood vessel such that a funnel mouth of the catheter is proximate an obstruction (e.g., a clot), aspirating in a proximal direction until the obstruction becomes lodged in the funnel mouth, and continuing to aspirate while simultaneously either torquing a guide wire, or injecting a solution through an injection catheter, where either the guide wire or injection catheter is positioned inside a lumen of the catheter. The use of either the guide wire or injection catheter can help to macerate the obstruction while aspirating fragments of the obstruction in the proximal direction through the catheter.
An example system configured to retrieve an obstruction from a blood vessel can include an aspiration catheter and a guide wire. The aspiration catheter can include an elongate body including a proximal end, a distal end, and a lumen sized to receive at least a first portion of the obstruction therein. The aspiration catheter can also include a funnel continuous with the distal end of the elongate body and including a funnel mouth sized to receive at least a second portion of the obstruction therein. The guide wire can be sized to slide through the lumen and can include one or more auger fins disposed at a distal end of the guide wire. The guide wire can be configured to be torqued such that the auger fins macerate the obstruction into fragments as one or more of the fragments of the obstruction are aspirated in a proximal direction through the aspiration catheter.
The elongate body of the aspiration catheter can have a single continuous structure and can have a first inner diameter. The funnel mouth can be perpendicular to the longitudinal axis and can have a second inner diameter. The first inner diameter of the elongate body can be smaller than the second inner diameter of the funnel mouth. As such, the second portion of the obstruction, which can be received through the funnel mouth, can be larger than the first portion of the obstruction, which can be received through the elongate body.
The guide wire can be configured such that there is a certain distance between the distal end of the guide wire and the funnel mouth of the aspiration catheter such that the guide wire does not extend past the distal end of the catheter.
Each of the auger fins of the guide wire can be the same size. The auger fins can be sized to have minimal clearance with the first inner diameter of the elongate body in order to displace the obstruction in the proximal direction jointly with aspiration force. The one or more fragments of the obstruction can be aspirated through the funnel mouth and in the proximal direction around the auger fins.
Another example system configured to retrieve an obstruction from a blood vessel can include an aspiration catheter and an injection catheter. The aspiration catheter can include an elongate body including a proximal end, a distal end, and a lumen sized to receive at least a first portion of the obstruction therein. The aspiration catheter can also include a funnel continuous with the distal end of the elongate body and including a funnel mouth sized to receive at least a second portion of the obstruction therein. The injection catheter can be configured in the lumen of the elongate body, and can include an orifice positioned approximate the distal end of the injection catheter. The injection catheter can be configured to produce a jet through the orifice such that the jet macerates the obstruction into fragments as one or more of the fragments of the obstruction are aspirated in the proximal direction around the injection catheter and through the aspiration catheter.
The elongate body of the aspiration catheter can have a single continuous structure and can have a first inner diameter. The funnel mouth can be perpendicular to the longitudinal axis and can have a second inner diameter. The first inner diameter of the elongate body can be smaller than the second inner diameter of the funnel mouth. As such, the second portion of the obstruction, which can be received through the funnel mouth, can be larger than the first portion of the obstruction, which can be received through the elongate body.
The distal end of the injection catheter can be closed. The injection catheter can be configured such that there is a certain distance between the distal end of the injection catheter and the funnel mouth of the aspiration catheter such that the injection catheter does not extend past the distal end of the catheter. The injection catheter can be either integral with the elongate body, or separate from the elongate body and sized to slide through the lumen of the elongate body.
An example method of retrieving an obstruction from a blood vessel can include one or more of the following steps executed by a person skilled in the pertinent art. The example method can include positioning an aspiration catheter such that a funnel mouth of a funnel disposed at the distal end of the aspiration catheter is proximate the obstruction. A negative pressure region can be created within the blood vessel by aspirating through a lumen of the aspiration catheter until a proximal portion of the obstruction becomes lodged in the funnel mouth. A clot macerating device, such as a guide wire or injection catheter, can be positioned inside the lumen of the aspiration catheter, and can be actuated thereby macerating the obstruction into fragments while simultaneously aspirating one or more of the fragments of the obstruction in the proximal direction through the aspiration catheter.
The clot macerating device can be configured such that there is a certain distance between the distal end of the clot macerating device and the funnel mouth of the aspiration catheter, and the one or more fragments of the obstruction can be aspirated in the proximal direction around the clot macerating device.
The above and further aspects of this invention are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.
As used herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, “about” or “approximately” may refer to the range of values ±20% of the recited value, e.g. “about 90%” may refer to the range of values from 71% to 99%.
The example systems and methods of treatment described herein generally involve delivering an aspiration catheter and a clot macerating device, such as an auger-style or wire loop guide wire or an injection catheter, to a blood vessel obstruction, e.g., a clot. The clot can be aspirated, by the aspiration catheter, in a proximal direction through a lumen of the aspiration catheter and around either the guide wire or the injection catheter. The example systems and methods can fully ingest a clot at a treatment site and aspirate the clot through the catheter while ensuring the clot, or smaller fragments of the clot, do not break off or become uncorked from the catheter tip.
In some such examples including a guide wire, the guide wire may have one or more auger fins disposed at the distal end of the guide wire. The guide wire may be torqued such that the clot can be macerated, and macerated fragments of the clot can be conveyed in the proximal direction around the auger fins and through the aspiration catheter. Simultaneous aspiration can also be conducted through the aspiration catheter to further help aspirate the clot fragments in the proximal direction through the aspiration catheter.
In other such examples including a guide wire, the guide wire may have one or more wire loops disposed at the distal end of the guide wire. The guide wire may be torqued such that the clot can be macerated, and macerated fragments of the clot can be conveyed via simultaneous aspiration in the proximal direction around and/or through the wire loop(s) and through the aspiration catheter.
In other such examples including an injection catheter, the injection catheter may have an orifice at or near the distal end of the injection catheter such that a solution (e.g., saline) may be injected through the orifice to create a jet. The jet can help to macerate the clot, while simultaneous aspiration can help to aspirate the macerated clot fragments in the proximal direction through the aspiration catheter.
Various example systems and methods are presented herein. Features from each example are combinable with other examples as understood by persons skilled in the pertinent art.
During the illustrated step, negative pressure from aspiration 16 creates a force on the clot 12 to draw the proximal portion 12b of the clot 12 into the funnel mouth 110 of the funnel 108. Simultaneously, guide wire 112 is torqued 22, such that the auger fins 114 can macerate the clot 12 into fragments. The auger fins 114 of guide wire 112 can convey the macerated fragments of clot 12 in a proximal direction 18 through the aspiration catheter 104. Simultaneous aspiration 16 can be used along with the torquing of the guide wire 112 to help support or supplement such conveyance of the macerated fragments.
As shown in
The guide wire 112 is positioned in the lumen 106c of elongate body 106 such that there is a distance L1 between the distal end 112a of the guide wire 112 and the funnel mouth 110 of the aspiration catheter 104. This distance L1 helps to ensure the distal end 112a of the guide wire 112 does not inadvertently pierce or puncture the clot 12 such that a portion of the clot 12 might break off from the clot 12 outside of, or distal to, the funnel mouth 110. Such broken portion of the clot 12 could re-block the blood vessel 10 and provide a challenge for later retrieval. Instead, the distance L1 helps to ensure the clot 12 may be aspirated 16 in a proximal direction 18 such that it becomes lodged or corked in the funnel mouth 110 before the auger fins 114 start to macerate the clot 12. Additionally, this process helps to ensure the clot 12 is macerated inside the funnel 108.
The auger fins 114 of guide wire 112 can each be of the same size, and can be sized such that there is minimal clearance with the inner diameter D1 of elongate body 106. Providing such minimal clearance helps to ensure the auger fins 114 can independently convey clot fragments in the proximal direction 18 of the aspiration catheter 104, but can also do so jointly with aspiration force 16.
During the illustrated step, negative pressure from aspiration 16 creates a force on the clot 12 to draw the proximal portion 12b of the clot 12 into the funnel mouth 310 of the funnel 308. Simultaneously, a solution (e.g., saline) is injected through the orifice 314 to produce a jet 316 that macerates the clot 12 into fragments as one or more of the fragments of the clot 12 are aspirated in a proximal direction 18 through the aspiration catheter 304.
As shown in
The injection catheter 312 can be configured to be either integral with the elongate body 306, as illustrated in
As shown in
Alternatively, as shown in
In block 802, an operator (e.g., a physician) can position the aspiration catheter 104 in a blood vessel 10 of a patient such that the funnel mouth 110 of the funnel 108 is proximate the clot 12 (
In block 804, the operator can then begin to aspirate 16 in a proximal direction 18 through the aspiration catheter 104 until a proximal portion 12b of the clot 12 becomes lodged in the funnel mouth 110 (
In block 806, the operator can position the guide wire 112 inside a lumen 106c of the aspiration catheter 104. The guide wire 112 can include one or more auger fins 114 disposed at a distal end 112a of the guide wire 112 (
In block 808, the operator can torque the guide wire 112 thereby spinning or screwing the auger fins 114 such that they begin to macerate the clot 12 (
In block 806a, the operator can position the guide wire 112 inside a lumen 106c of the aspiration catheter 104. The guide wire 112 can include one or more wire loops 214 disposed at a distal end 112a of the guide wire 112.
In block 808a, the operator can torque the guide wire 112 thereby spinning the one or more wire loops 214 such that the wire loop(s) 214 begin to macerate the clot 12. Simultaneously, the operator may aspirate 16 in the proximal direction 18 around and/or through the wire loop(s) 214 and through the aspiration catheter 104.
In block 902, an operator (e.g., a physician) can position the aspiration catheter 304 in a blood vessel 10 of a patient such that the funnel mouth 310 of the funnel 308 is proximate the clot 12 (
In block 904, the operator can begin to aspirate 16 in a proximal direction 18 through the aspiration catheter 304 until a proximal portion 12b of the clot 12 becomes lodged in the funnel mouth 310 (
In block 906, the operator can inject a solution through the injection catheter 312 thereby producing a jet 316 through the orifice 314 of the injection catheter 312. The jet 316 can macerate the clot 12 while the operator simultaneously aspirates the macerated clot fragments of the clot 12 in a proximal direction 18 through the aspiration catheter 304 (
The descriptions contained herein are examples of embodiments of the invention and are not intended in any way to limit the scope of the invention. As described herein, the invention contemplates many variations and modifications of structures and methods, including alternative materials, alternative configurations of component parts, and alternative method steps. Modifications and variations apparent to those having skill in the pertinent art according to the teachings of this disclosure are intended to be within the scope of the claims which follow.