Patent Application
20240065713
This disclosure relates to devices and methods of removing acute blockages from blood vessels.
The World Health Organization estimates that 15,000,000 blood clots occur annually. Clots may develop and block vessels locally without being released in the form of an embolus—this mechanism is common in the formation of coronary blockages. Acute obstructions may include blood clots, misplaced devices, migrated devices, large emboli and the like. Thromboembolism occurs when part or all of a thrombus breaks away from the blood vessel wall. This clot is then carried in the direction of blood flow. The large vessels of the brain include the Internal Carotid Artery (ICA), Middle Cerebral Artery (MCA), Vertebral Artery (VA), and the Basilar Artery (BA). Clots can include a range of morphologies and consistencies. Long strands of softer clot material may tend to lodge at bifurcations or trifurcations, resulting in multiple vessels being simultaneously occluded over significant lengths. Older clot material can also be less compressible than softer fresher clots, and under the action of blood pressure it may distend the compliant vessel in which it is lodged. Clots may also vary greatly in length, even in any one given area of the anatomy. For example, clots occluding the middle cerebral artery of an ischemic stroke patient may range from just a few millimeters to several centimeters in length.
Of the 15,000,000 clots that occur annually, one-third of patients die, and another one-third are disabled. Two of the primary factors associated with mortality in these patients are the occlusion location and the time to treatment. Large-vessel occlusions present in 46% of unselected acute stroke patients presenting in academic medical centers, are associated with higher stroke severity. These more proximal vessels feed a large volume of brain tissue, ergo clinicians use the presenting NIHSS (National Institute of Health Stroke Scale) score as an indicator of large-vessel occlusion.
With this, it is understood that an ischemic stroke may result if the clot lodges in the cerebral vasculature. It is estimated that 87% of stroke cases are acute ischemic stroke (AIS). In the United States alone, roughly 700,000 AIS cases occur every year and this number is expected to increase with an ageing population. Occlusion of these large arteries in ischemic stroke is associated with significant disability and mortality. Revascularization of intracranial artery occlusions is the therapeutic goal in stroke therapy. Endovascular mechanical revascularization (thrombectomy) is an increasingly used method for intracranial large vessel recanalization in acute stroke. Currently, a number of mechanical recanalization devices are in clinical use. First generation devices included the Merci Retriever device. Newer devices based on stent-like technology, referred to as “stentrievers” or “stent-retrievers”, are currently displacing these first generation thrombectomy devices for recanalization in acute ischemic stroke.
There are significant challenges associated with designing clot removal devices that can deliver high levels of performance. There are also a number of access challenges that make it difficult to deliver devices. For example, the vasculature in the area in which the clot may be lodged is often fragile and delicate and neurovascular vessels are more fragile than similarly sized vessels in other parts of the body and are in a soft tissue bed. Excessive tensile forces applied on these vessels could result in perforations and hemorrhage. Pulmonary vessels are larger than those of the cerebral vasculature, but are also delicate in nature, particularly those more distal vessels.
Stent-like clot retriever devices are being increasingly used to remove clots from cerebral vessels of acute stroke patients, but such devices are not without disadvantages. A stent-like clot retriever relies on its outward radial force to grip the clot. If the radial force is too low, the device will lose its grip on the clot. If the radial force is too high, the device may damage the vessel wall and may require too much force to withdraw. Such devices that have sufficient radial force to deal with all clot types may therefore cause vessel trauma and serious patient injury, and retrievers that have appropriate radial force to remain atraumatic may not be able to effectively handle all clot types. In this respect, retriever devices may differ in size, shape, and physical properties, such as radial force, as discussed above, ease of deployment, friction, radiopacity and interaction with vessel wall. See, Loh Y, Jahan R, McArthur D. Recanalization rates decrease with increasing thrombectomy attempts. American Journal of Neuroradiology. 2010 May; 31(5):935-9; and Arai D, Ishii A, Chihara H, Ikeda H, Miyamoto S. Histological examination of vascular damage caused by stent retriever thrombectomy devices, J Neurointerv Surg. 2016 October; 8(10):992-5. Some designs have also been based on in-vitro stroke models that incorporate realistic clot analogs derived from animal blood that represent the wide range of human clots retrieved from stroke patients. See, Eugéne F, Gauvrit J-Y, Ferré J-C, Gentric J-C, Besseghir A, Ronziere T, et al. One-year MR angiographic and clinical follow-up after intracranial mechanical thrombectomy using a stent retriever device, Am. J. Neuroradiol. 2015 January; 36(1):126-32 (18), each of which are incorporated by reference herein in their entirety.
Currently, intravenous (IV) lytics are used for patients presenting up to 4.5 hours after symptom onset. Current guidelines recommend administering IV lytics in the 3-4.5-hour window to those patients who meet the ECASS 3 (European Cooperative Acute Stroke Study 3) trial inclusion/exclusion criteria. Since a large percentage of strokes presenting at hospitals are large vessel occlusions, this is an important clinical challenge to address. Additionally, not all patients may be treated with thrombolytic therapy, and so mechanical thrombectomy is a valuable alternative in patients contraindicated to t-PA (tissue plasminogen activator) or where t-PA treatment was not effective.
Though success rates are high when utilizing mechanical thrombectomy, there are still a proportion of patients for which adequate reperfusion cannot be achieved, certainly, in part, due to the clot not being retrieved. In view of these clear performance disadvantages, further reperfusion and patient outcomes advances in AIS treatment are warranted. Further, there is a need to treat challenging situations where the current stent retrievers are unsuccessful during the first few attempts at clot removal. The solution of this disclosure resolves these and other issues of the art.
The subject of this disclosure is the use of a clot revascularization device to treat ischemic stroke for restoring perfusion and/or removing a clot and other obstructions from the neurovascular arteries and veins as well as other vascular beds.
In some examples, a method is disclosed to restore blood flow in neurovasculature of a human patient experiencing ischemic stroke, the method including identifying a human patient within a plurality of human patients at risk of comprising a thrombus; passing a revascularization device as a first-line device to a blood vessel of the respective human patent of a plurality of human patients for retrieving a thrombus; and removing the revascularization device to restore perfusion to the blood vessel and achieve approximately 80% revascularization rate after last pass of the revascularization device under a modified treatment in cerebral infarction score of equal to or greater than grade 2b (mTICI>2b) for the plurality of human patients comprising a thrombus within a predetermined time period of natural stroke symptom onset.
In certain examples, the method can further include detecting, prior to the step of passing the revascularization device as the first-line device, an initial revascularization rate of the respective human patient of the plurality of human patients less than a grade 2b (mTICI<2b).
In some examples, achieving approximately 80% revascularization rate for the plurality of human patients under the modified treatment in cerebral infarction score of equal to or greater than grade 2b (mTICI≥2b) can include less than three passes of the revascularization device as the first-line device. In certain other examples, achieving approximately 80% revascularization rate for the plurality of human patients under the modified treatment in cerebral infarction score of equal to or greater than grade 2b (mTICI≥2b) can include an average of approximately 2.4 passes of the revascularization device as the first-line device.
In some examples, the method can further include reducing, by the step of passing the revascularization device as the first-line device, post-procedural clinical complications selected from at least one of vessel dissection, vessel perforation, hematoma, emboli in new territory, infarction in new territory, or hemorrhagic transformation.
In some examples, the method can be performed within at least 11 hours of stroke symptom onset.
In some examples, the thrombus can be positioned in an internal carotid artery, a M1 segment and/or a M2 segment of a middle cerebral artery, a vertebral artery, or a basilar artery of the human patient.
In some examples, the revascularization device can include a collapsed delivery configuration and an expanded deployed configuration. The revascularization device can also include a proximal pinch section having a spiral shape that includes a spiral pitch. The revascularization device also includes a distal section having a barrel shape.
In some examples, the revascularization device can be configured to position the thrombus against a wall of the blood vessel and then pinch the thrombus with the proximal pinch section.
In some examples, in the expanded deployed configuration, the revascularization device can include peaks of the proximal pinch section that can be laterally spaced-apart. In addition, the revascularization device under tension can be configured to pinch the thrombus between the peaks. In some examples, the proximal pinch section can include a plurality of cells defined by struts and crowns connected to corresponding struts and crowns. At least some of the struts or the crowns of the proximal pinch section can be aligned with a wave-like form to enhance embedding of clot. In some examples, the proximal pinch section can include one or more clot gripping features.
An exemplary embodiment provides a method of restoring blood flow in neurovasculature by removing thrombus in a plurality of human patients experiencing ischemic stroke. The method can include passing a revascularization device by, through, or about a thrombus in a blood vessel of each of the plurality of human patients to restore perfusion to the blood vessel. The method can achieve at least approximately 68.8% revascularization rate after an average of less than two passes of the revascularization device as a second-line device for the plurality of human patients under a modified treatment in cerebral infarction score of equal to or greater than a grade of 2b (mTICI≥2b). The thrombus retrieved can be fibrin-rich and include more fibrin than red blood cells.
In some examples, prior to passing the revascularization device by, through, or about the thrombus in the blood vessel of each of the plurality of human patients, the method can include passing a stent retriever device by, through, or about the thrombus in the blood vessel of each of the plurality of human patients. After the step of passing the stent retriever device by, through, or about the thrombus in the blood vessel of each of the plurality of human patients, and prior to passing the revascularization device by, through, or about the thrombus in the blood vessel of each of the plurality of human patients, the method can include detecting a revascularization rate of a respective human patient of the plurality of human patients less than a grade 2b (mTICI<2b).
In some examples, prior to passing the revascularization device by, through, or about the thrombus in the blood vessel of each of the plurality of human patients, the method can further include switching to the revascularization device as the second-line device to restore perfusion to the blood vessel by passing the revascularization device by, through, or about the thrombus to achieve at least approximately 68.8% revascularization rate after an average of approximately 1.7 passes of the revascularization device for the plurality of human patients under the modified treatment in cerebral infarction score of equal to or greater than a grade of 2b (mTICI≥2b).
In some examples, the revascularization device can include a collapsed delivery configuration and an expanded deployed configuration; a proximal pinch section comprising a spiral shape comprising a spiral pitch; and a distal section comprising a barrel shape. The revascularization device can be configured to position the thrombus against a wall of the blood vessel and then pinch the thrombus with the proximal pinch section.
In some examples, the step of passing the revascularization device can include retracting the revascularization device, after being passed by, through or about the thrombus, while pinching the thrombus.
In some examples, the revascularization device can be configured to remove the thrombus or portions thereof that remain after passing the stent retriever device as a first-line device.
In some examples, the thrombus or portion thereof can include more fibrin than red blood cells.
To the accomplishment of the foregoing and related ends, certain illustrative aspects are described herein in connection with the following description and the appended drawings. These aspects are indicative, however, of but a few of the various ways in which the principles of the claimed subject matter may be employed and the claimed subject matter is intended to include all such aspects and their equivalents. Other advantages and novel features may become apparent from the following detailed description when considered in conjunction with the drawings.
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.
Although example embodiments of the disclosed technology are explained in detail herein, it is to be understood that other embodiments are contemplated. Accordingly, it is not intended that the disclosed technology be limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The disclosed technology is capable of other embodiments and of being practiced or carried out in various ways.
It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. By “comprising” or “containing” or “including” it is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.
In describing example embodiments, terminology was resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. It is also to be understood that the mention of one or more steps of a method does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Steps of a method may be performed in a different order than those described herein without departing from the scope of the disclosed technology. Similarly, it is also to be understood that the mention of one or more components in a device or system does not preclude the presence of additional components or intervening components between those components expressly identified.
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%.
As discussed herein, vasculature of a “subject” or “patient” may be vasculature of a human or any animal. It should be appreciated that an animal may be a variety of any applicable type, including, but not limited thereto, mammal, veterinarian animal, livestock animal or pet type animal, etc. As an example, the animal may be a laboratory animal specifically selected to have certain characteristics similar to a human (e.g., rat, dog, pig, monkey, or the like). It should be appreciated that the subject may be any applicable human patient, for example.
As discussed herein, “operator” may include a doctor, surgeon, or any other individual or delivery instrumentation associated with delivery of a clot revascularization device to the vasculature of a subject.
As discussed herein, “thrombus” can be understood as a clot in the circulatory system that remains in a site of the vasculature hindering or otherwise obstructing flow in a blood vessel. The terms “clot”, “thrombus”, “obstruction”, “occlusion”, “blockage”, and/or the like, can be and are often used interchangeably throughout this disclosure.
Delivery of a “revascularization device” is typically accomplished via delivery of one or more catheters into the femoral artery and/or the radial artery, guided into the arteries of the brain, vascular bypass, angioplasty, and/or the like. “Revascularization devices” can include, but not be limited to, one or more stents, stentrievers, clot removal devices, clot revascularization devices, aspiration systems, one or more combinations thereof, and/or the like, each of which are often used interchangeably throughout this disclosure.
As discussed herein, the term “safety”, as it relates to a clot revascularization device, delivery system, or method of treatment refers to a relatively low severity of adverse events, including adverse bleeding events, infusion, or hypersensitivity reactions. Adverse bleeding events can be the primary safety endpoint and include, for example, major bleeding, minor bleeding, and the individual components of the composite endpoint of any bleeding event.
As discussed herein, unless otherwise noted, the term “clinically effective” (used independently or to modify the term “effective”) can mean that it has been proven by a clinical trial wherein the clinical trial has met the approval standards of U.S. Food and Drug Administration, EMEA or a corresponding national regulatory agency. For example, a clinical study may be an adequately sized, randomized, double-blinded controlled study used to clinically prove the effects of the reperfusion device and related systems of this disclosure. Most preferably to clinically prove the effects of the reperfusion device with respect to an ischemic event, for example, to achieve a clinically effective outcome in for the patient suffering the ischemic event (e.g., mRS less than or equal to 2) and/or achieve reperfusion the vessel(s) afflicted by the ischemic event.
As used herein, unless otherwise noted, the term “predetermined time period” as it relates to a procedure of restoring blood flow in neurovasculature of a human patient means the number of seconds, minutes, hours, days, or week from the onset of natural stroke symptoms until the clinical outcome is achieved for a particular human patient. In some embodiments, the predetermined time period can include performing the procedure of restoring blood flow in neurovasculature within approximately 8, 9, 10, 11, and/or 12 hours of stoke symptom onset.
As discussed herein, the term “computed tomography” or CT means one or more scans that make use of computer-processed combinations of many X-ray measurements taken from different angles to produce cross-sectional (tomographic) images (virtual “slices”) of specific areas of a scanned object, allowing the user to see inside the object without cutting. Such CT scans of this disclosure can refer to X-ray CT as well as many other types of CT, such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). The present disclosure is related to systems, methods and devices restoring perfusion in blood vessels, and in particular occlusions from cerebral vessels.
As an example,
As applicable procedure guidelines change with respect to the use of clot revascularization devices for treatment of ischemic events, it is also conceivable that device 200 could be used more than 24 hours from symptom onset. Device 200 can be understood as including features more clearly described in Appendix 1 of U.S. Provisional Application No. 63/400,240, as incorporated by reference in its entirety from the U.S. Provisional applications from which this application claims priority, which includes U.S. Pat. Nos. 10,292,723; 10,363,054; 10,617,435; 11,253,278; and 11,147,572, each of which are incorporated by reference in their entirety as if set forth verbatim herein. Note that revascularization devices can also be introduced through the wrist artery (radial access) or directly through the carotid artery. While both radial and carotid access avoids the aortic arches, there are other drawbacks. However, all three approaches are considered to be known to ones of skill in this art.
Once across the site of vessel occlusion, device 200 is deployed to entrap the clot and allow it to be retrieved, hence restoring blood flow. It is understood that device 200 of this disclosure would be used with a delivery system to the site of the clot, including a guide catheter, a microcatheter, and/or a guidewire. It is also contemplated that device 200 of this disclosure could be used in connection with an aspiration system to further facilitate restoring perfusion to the vasculature.
A longitudinal center axis of the distal section 222 can be in a barrel shape or otherwise tubular with a lumen and can be offset from a center line of the spiral shape of section 221 to assist in achieving uniform (e.g., low strain) connection between the sections. The distal end of the spiral section is orientated so that it is perpendicular to the proximal face of the barrel section. In this orientation both the struts connecting the spiral section to the barrel section are equal length and have equivalent levels of strain regardless of the cut pattern orientation on the heat forming mandrel. In other iterations the spiral of section 221 can be oriented at an angle to the barrel of section 222.
In some examples, device 200 is configured for removing fibrin rich and/or platelet rich clots. Device 200 can have an expandable structure with a constrained delivery configuration, an expanded clot engaging deployed configuration, and an at least partially constrained clot pinching configuration, whereby at least a portion of the expandable structure is configured to engage the clot in the expanded deployed configuration and to pinch clot on movement from the deployed configuration to the clot pinching configuration. In the clot pinching configuration, device 200 can pinch at least a portion of the clot body as its expandable element is at least partially collapsed from a fully expanded configuration. The expandable element of device 200 can be configured to come into contact with at least a portion of the clot, while maintaining the position of a shaft (e.g., shaft 206) steadfast and effecting pinching substructure of the device so as to pinch at least a portion of the clot and retracting device 200 and the pinched occlusive clot from the patient.
Device 200 can have an elongate shaft 206. Shaft 206 can have a distal end that extends interior of the artery and a proximal end that extends exterior of the artery. Shaft 206 may be a tapered wire shaft, and may be made of stainless steel, MP35N, Nitinol or other material of a suitably high modulus and tensile strength. Shaft 206 can have a coil adjacent to its distal end and is proximal of the outer member and inner tubular member. The coil may be coated with a low friction material or have a polymeric jacket positioned on the outer surface.
It is noted, however, that other measures of cerebral scoring standards, such as expanded TICI (eTICI), other known and/or to-be-developed cerebral scoring standards, provide measures of cerebral scoring and are thus directly and/or indirectly applicable in understanding scope of the presently disclosed solution. eTICI scale is a 7-point compilation of TICI grades that reflects all previously reported thresholds used to define reperfusion after endovascular stroke therapy. For example, eTICI grade 0, just as mTICI, can be equivalent to no reperfusion or 0% filling of the downstream territory. eTICI 1 can indicate thrombus reduction without any reperfusion of distal arteries, including reperfusion of less than half or 1-49%. eTICI of 2b50 can be 50-66% reperfusion. eTICI 2b67 can be 67-89% reperfusion, exceeding TICI but below TICI2C. eTICI 2c can be equivalent to TICI 2C or 90-99% reperfusion. eTICI 3 can be complete or 100% reperfusion, such as TICI 3. It is understood that one of ordinary skill in the art can also correlate between currently known cerebral scoring standards and/or to-be-developed cerebral scoring standards (e.g., from mTICI to eTICI).
As discussed herein, symptomatic intracranial hemorrhage, “sICH” is any extravascular blood in the brain or within the cranium associated with clinical deterioration, as defined by an increase of 4 points or more in the score on the NIHSS, or that leads to death and is identified as the predominant cause of the neurologic deterioration. For the purpose of this disclosure, subjects with sICH identified through all posttreatment scans up to the 24-hour time-point (including those performed due to clinical deterioration), were considered in the study discussed herein.
This disclosure is more clearly understood with a corresponding study discussed more particularly below with respect to treatment of ischemic stroke, which is in Appendix 2 of U.S. Provisional Application No. 63/400,240, which is incorporated by reference in its entirety as if set forth verbatim herein. In the study of this present disclosure, real-world outcomes and clot composition using device 200 for challenging clots were assessed in a retrospective review of patients treated at two high-volume comprehensive stroke centers. In particular, the study assessed consecutive patients with AIS who underwent MT using the device 200 at 2 high-volume centers from December 2019 to May 2021. Use of device 200 was at the interventionalist's discretion at the time of the procedure and could be deployed as first-line treatment for clots deemed challenging to remove or after failed attempts using standard techniques. The study was approved by the local ethics committee. Informed consent was waived owing to the retrospective nature of the study.
It is understood that data and study information is presented herein for purposes of illustration and should not be construed as limiting the scope of the disclosed technology in any way or excluding any alternative or additional embodiments. Data was collected at baseline (prior to thrombectomy), during the procedure, and post-procedure. In general, device 200 is traditionally used in procedures for remove tough clots after prior devices have failed to remove the tough clot. The use of device 200 as a first-line device has not been done before. Therefore, the objective of this study was to assess the efficacy of device 200 in a real-world setting with patients where device 200 was used as a first-line device and/or the first two passes with another stent-retriever did not achieve an mTICI score of 2b or better. The rate of effectiveness achieved was considered as well as clot characteristics (e.g., Composition of clot components, per pass, Red Blood Cells (RBC), White Blood Cells (WBC), platelets, fibrin, and other proteins), as evaluated by the independent Central Lab and clinical outcomes. The study was a retrospective study that evaluated real-world outcomes using device 200 for challenging clots at two high-volume comprehensive stroke centers. In particular, the study evaluated device 200 as either a first-line device (5 subjects out of 37 total subjects, 13.5%) or second-line device after two unsuccessful passes of another stent-retriever (32 subjects out of 37 total subjects), in the treatment of acute ischemic stroke.
Using standard interventional techniques, access to the arterial system and using angiography, the location of the occluded vessel was determined. Then, an appropriate guide catheter, sheath or balloon guide catheter was advanced as close to the occlusion site as possible. In some examples, rotating hemostasis valve (RHV) was connected to the proximal end of this catheter and a continuous flush system. With the aid of a suitable guidewire, and using standard catheterization techniques and fluoroscopic guidance, an appropriately sized microcatheter was advanced up to and across the occlusion so that the distal end of the microcatheter was positioned distal to the occlusion. The guidewire was removed, and device 200 was inserted and advanced into the microcatheter. In some examples, immediately prior to introducing a guide catheter, the physician in the study performed an angiogram of the affected intracranial artery. The purpose of the pre-procedure angiogram was to confirm the location of the occlusion; that the subject remained suitable for treatment with mechanical thrombectomy; and that the subject remains a candidate for the study per the eligibility criteria.
In some examples, device 200 continues to be advanced until radiopaque distal markers of device 200 approach the distal region of the microcatheter. Device 200 was positioned in the clot ideally such that the end of the proximal radiopaque coil was aligned with the proximal face of the clot. To fully deploy device 200 within the clot, the microcatheter was retracted until the distal tip of the microcatheter was positioned over the proximal radiopaque coil of device 200.
The primary endpoint was successful revascularization at the end of the procedure, without rescue as determined by an Independent Core Lab, where the successful revascularization is defined as achieving an mTICI score of 2b or greater. Revascularization was measured using modified Thrombolysis in Cerebrovascular Infarction (“mTICI”) inclusive of the 2c rating that is described in
Other endpoints of the study included evaluating successful revascularization (final mTICI≥2c), which was understood as the rate of achieving an mTICI score of 2c or greater at the end of the procedure, as determined by an Independent Core Lab; first study pass (third procedural pass) recanalization (mTICI≥2b), which was understood as the rate of achieving an mTICI score of 2b or greater after the third procedural pass, as determined by an Independent Core Lab with two-sided exact 95% confidence intervals conducted around the percentage; Occurrence of Embolization to a New Territory (ENT), which was understood as the rate of embolization in a previously unaffected territory, following the fifth procedural pass, or the final procedural pass, if earlier; pre-stroke modified Rankin Scale (mRS) scores (as provided in
Key assessments of clot retrieval by device 200 included number of passes (prior to device 200, device 200 only and all devices), substantial reperfusion (modified Thrombolysis in Cerebral Infarction (“mTICI”) 2b or higher prior to device 200, after last device 200 pass and with all devices), rate of any clot material retrieval (“non-empty” passes) for device 200 vs. earlier MT passes, and use of device 200 in the final pass where end-of-procedure substantial reperfusion was achieved. Reasons for using or switching to device 200 were also recorded.
Clinical outcomes included NIHSS change from baseline at 48 hours post-procedure, good (0-2) and fair (0-3) mRS outcomes (discharged to 7 days after the procedure and at final assessment) and all-cause mortality during primary hospitalization. As outlined in
One of the centers had the capacity to collect clot material in 78.3% (18/23) cases. Retrieved clots were collected per pass, immediately fixed in 10% phosphate buffered formalin and shipped to an independent lab for histological analysis including Martius Scarlet Blue staining, as previously described in Duffy S, McCarthy R, Farrell M, et al. Per-Pass Analysis of Thrombus Composition in Patients with Acute Ischemic Stroke Undergoing Mechanical Thrombectomy. Stroke 2019; 50:1156-1163. Upon arrival, gross photos were taken of all clots and the extracted clot area was measured using ImageJ as previously described in Rossi R, Fitzgerald S, Gil S M, et al. Correlation between acute ischaemic stroke clot length before mechanical thrombectomy and extracted clot area: Impact of thrombus size on number of passes for clot removal and final recanalization. Eur. Stroke J. 2021; 6(3):254-261. Following standard tissue processing and paraffin embedding protocols, clots were cut into 3 μm sections and stained. Orbit image analysis was used to quantify the histological composition (red blood cells, white blood cells, fibrin, platelets/other).
The study collected imaging data as assessed by Imaging Core Lab, including Baseline—CT/MR imaging (e.g., Infarct volume, Clot location, Clot length, Clot radiodensity on CT/Susceptibility Vessel Sign (SVS) on MRI), procedural angiography (e.g., mTICI score for every pass, clot location for every pass (proximal face of clot), emboli to new territories), post procedure as to CT/MR imaging (e.g., intracranial hemorrhage). Hemorrhages were classified according to the following categories HI 1—Scattered small petechiae, no mass effect; HI 2—Confluent petechiae, no mass effect; PH1—Hematoma within infarcted tissue, occupying <30%, no substantive mass effect; PH2—Hematoma occupying 30% or more of the infarcted tissue, with obvious mass effect; RIH—Parenchymal hematoma remote from infarcted brain tissue; IVH—Intraventricular Hemorrhage; SAH—Subarachnoid Hemorrhage; and SDH—Sub Dural Hemorrhage. Reperfusion as a primary endpoint was not assessed by the Core Lab.
Prior to clot retrieval, the microcatheter was re-advanced to the clot while holding device 200 push wire static until a predetermined resistance was met. If the operator felt significant resistance, she did not continue to advance. Device 200 was withdrawn with microcatheter slowly and carefully as a single unit to the guide catheter while aspirating through the guide and maintaining microcatheter and device 200 position relative to each other during the withdrawal step. In some examples, vigorous aspiration was applied by syringe and device 200 withdrawn with microcatheter into the guide catheter and continue to aspirate until device 200 reached the RHV on the guide. The operator could then disconnect the RHV from the guide and remove device 200, microcatheter and RHV together from the guide. Device 200 was used for up to three retrieval attempts. If an additional pass was to be made with device 200, then any captured thrombus was removed from device 200, and device 200 was cleaned in heparinized saline, rubbing gently from proximal to distal to remove any residual thrombus material.
Subjects presenting with AIS were evaluated and treated by the physician according to institutional practice. Endovascular treatment with device 200, and the other stent-retrievers, was performed per hospital standard technique and in accordance with the applicable devices' IFU. As outlined in
The most common reason for using device 200 (32/37 cases) involved failure of up to 4 devices in up to 6 thrombectomy passes. Reasons for using device 200 as first-line treatment included suspected calcified lesion (3/37), known M1 stenosis (1/37) and intracranial internal carotid artery (ICA) stenosis (1/37).
As outlined in
As shown in
Reperfusion and clinical outcomes are summarized in
Prior to passing device 200, all 37 patients had an mTICI score lower than 2b, but the mTICI score equal to or greater than 2b after last pass of device 200 reached 70.3% (26/37) of patients, 37.8% (14/37) of which had an mTICI score equal to or greater than 2c.
Clot specimens from 18/37 (48.6%) cases that underwent composition analysis are summarized in
The clot retrieved in this study was richer in fibrin and platelet/other and poorer in red blood cells than levels typically reported in the literature. Similar composition profiles were observed in the overall cohort of clots which included fragments removed by all devices used in each case and the clot fragments removed specifically using device 200 as first-line or second-line treatment.
The extracted clot area and weight were similar in the overall and first-line device 200 cohorts. There was a trend to smaller clot in device 200 as second line and clots extracted with later passes were smaller.
The results of this series of patients with mainly fibrin- and platelet-rich clots support the utility of device 200 in cases that are typically challenging using standard approaches. Device 200 may be considered as a first-line device in patients with suspected or known tough clots.
The device 200 and related methods of use of this disclosure demonstrated high rates of substantial reperfusion and functional independence in patients with acute ischemic stroke secondary to large-vessel occlusions. The specific configurations, choice of materials and the size and shape of various elements can be varied according to particular design specifications or constraints requiring a system or method constructed according to the principles of the disclosed technology. Such changes are intended to be embraced within the scope of the disclosed technology. The presently disclosed embodiments, therefore, are considered in all respects to be illustrative and not restrictive. It will therefore be apparent from the foregoing that while particular forms of the disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the disclosure and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.
The following clauses list non-limiting embodiments of the disclosure:
Clause wherein, in the expanded deployed configuration, the revascularization device comprises peaks of the proximal pinch section are laterally spaced-apart and when under tension, pinching the thrombus between the peaks.
The present application claims the benefit of priority of U.S. Provisional Application No. 63/400,240, filed Aug. 23, 2022, the contents of which are incorporated herein by reference in its entirety as if set forth verbatim.
| Number | Date | Country | |
|---|---|---|---|
| 63400240 | Aug 2022 | US |
