Construction of a comprehensive endovascular test bed for research and device development in mechanical thrombectomy in stroke

OBJECTIVEThe development of new endovascular technologies and techniques for mechanical thrombectomy in stroke has greatly relied on benchtop simulators. This paper presents an affordable, versatile, and realistic benchtop simulation model for stroke.METHODSA test bed for embolic occlusion of cerebrovascular arteries and mechanical thrombectomy was developed with 3D-printed and commercially available cerebrovascular phantoms, a customized hydraulic system to generate physiological flow rate and pressure, and 2 types of embolus analogs (elastic and fragment-prone) capable of causing embolic occlusions under physiological flow.RESULTSThe test bed was highly versatile and allowed realistic, radiation-free mechanical thrombectomy for stroke due to large-vessel occlusion with rapid exchange of geometries and phantom types. Of the transparent cerebrovascular phantoms tested, the 3D-printed phantom was the easiest to manufacture, the glass model offered the best visibility of the interaction between embolus and thrombectomy device, and the flexible model most accurately mimicked the endovascular system during device navigation. None of the phantoms modeled branches smaller than 1 mm or perforating arteries, and none underwent realistic deformation or luminal collapse from device manipulation or vacuum. The hydraulic system created physiological flow rate and pressure leading to iatrogenic embolization during thrombectomy in all phantoms. Embolus analogs with known fabrication technique, structure, and tensile strength were introduced and consistently occluded the middle cerebral artery bifurcation under physiological flow, and their interaction with the device was accurately visualized.CONCLUSIONSThe test bed presented in this study is a low-cost, comprehensive, realistic, and versatile platform that enabled high-quality analysis of embolus–device interaction in multiple cerebrovascular phantoms and embolus analogs.

Download Full-text

A human brain test bed for research in large vessel occlusion stroke

Journal of Neurosurgery ◽

10.3171/2020.7.jns202278 ◽

2021 ◽

pp. 1-9

Author(s):

Daniel Gebrezgiabhier ◽

Yang Liu ◽

Adithya S. Reddy ◽

Evan Davis ◽

Yihao Zheng ◽

...

Keyword(s):

Human Brain ◽

Mechanical Thrombectomy ◽

Posterior Circulation ◽

Large Vessel ◽

Suction Catheter ◽

Large Vessel Occlusion ◽

Test Bed ◽

Anterior Circulation ◽

Vessel Occlusion ◽

Human Brains

OBJECTIVEEndovascular removal of emboli causing large vessel occlusion (LVO)–related stroke utilizing suction catheter and/or stent retriever technologies or thrombectomy is a new standard of care. Despite high recanalization rates, 40% of stroke patients still experience poor neurological outcomes as many cases cannot be fully reopened after the first attempt. The development of new endovascular technologies and techniques for mechanical thrombectomy requires more sophisticated testing platforms that overcome the limitations of phantom-based simulators. The authors investigated the use of a hybrid platform for LVO stroke constructed with cadaveric human brains.METHODSA test bed for embolic occlusion of cerebrovascular arteries and mechanical thrombectomy was developed with cadaveric human brains, a customized hydraulic system to generate physiological flow rate and pressure, and three types of embolus analogs (elastic, stiff, and fragment-prone) engineered to match mechanically and phenotypically the emboli causing LVO strokes. LVO cases were replicated in the anterior and posterior circulation, and thrombectomy was attempted using suction catheters and/or stent retrievers.RESULTSThe test bed allowed radiation-free visualization of thrombectomy for LVO stroke in real cerebrovascular anatomy and flow conditions by transmural visualization of the intraluminal elements and procedures. The authors were able to successfully replicate 105 LVO cases with 184 passes in 12 brains (51 LVO cases and 82 passes in the anterior circulation, and 54 LVO cases and 102 passes in the posterior circulation). Observed recanalization rates in this model were graded using a Recanalization in LVO (RELVO) scale analogous to other measures of recanalization outcomes in clinical use.CONCLUSIONSThe human brain platform introduced and validated here enables the analysis of artery-embolus-device interaction under physiological hemodynamic conditions within the unmodified complexity of the cerebral vasculature inside the human brain.

Download Full-text

Use of Patient Specific 3D Printed Neurovascular Phantoms To Simulate Mechanical Thrombectomy

10.21203/rs.3.rs-697127/v1 ◽

2021 ◽

Author(s):

Kelsey Sommer ◽

Mohammad Mahdi Shiraz Bhurwani ◽

Vincent Tutino ◽

Adnan Siddiqui ◽

Jason Davies ◽

...

Keyword(s):

Mechanical Thrombectomy ◽

Blood Clot ◽

Patient Specific ◽

P Value ◽

Fluid Temperature ◽

Flow Loop ◽

Vessel Occlusion ◽

Before And After ◽

Device Placement ◽

3D Printed

Abstract Background: The ability of the patient specific 3D printed neurovascular phantoms to accurately replicate the anatomy and hemodynamics of the chronic neurovascular diseases has been demonstrated by many studies. Acute occurrences, however, may still require further development and investigation and therefore we studied acute ischemic stroke (AIS). The efficacy of endovascular procedures such as mechanical thrombectomy (MT) for the treatment of large vessel occlusion (LVO), can be improved by testing the performance of thrombectomy devices and techniques using patient specific 3D printed neurovascular models.Methods: 3D printed phantoms were connected to a flow loop with physiologically relevant flow conditions, including input flow rate and fluid temperature. A simulated blood clot was introduced into the model and placed in the proximal Middle Cerebral Artery (MCA) region. Clot location, composition, length, and arterial angulation were varied and MTs were simulated using stent retrievers. Device placement relative to the clot and the outcome of the thrombectomy were recorded for each situation. Digital subtraction angiograms (DSA) were captured before and after LVO simulation. Recanalization outcome was evaluated using DSA as either ‘no recanalization’ or ‘recanalization’. Forty-two 3DP neurovascular phantom benchtop experiments were performed. Results: Clot angulation within the MCA region had the most significant impact on the MT outcome, with a p-value of 0.016. Other factors such as clot location, clot composition, and clot length correlated weakly with the MT outcome.Conclusions: This project allowed us to gain knowledge of how such characteristics influence thrombectomy success and can be used in making clinical decisions when planning the procedure and selecting specific thrombectomy tools and approaches.

Download Full-text

Use of patient specific 3D printed neurovascular phantoms to simulate mechanical thrombectomy

3D Printing in Medicine ◽

10.1186/s41205-021-00122-8 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Kelsey N. Sommer ◽

Mohammad Mahdi Shiraz Bhurwani ◽

Vincent Tutino ◽

Adnan Siddiqui ◽

Jason Davies ◽

...

Keyword(s):

Mechanical Thrombectomy ◽

Blood Clot ◽

Patient Specific ◽

Fluid Temperature ◽

Flow Loop ◽

Vessel Occlusion ◽

Before And After ◽

Device Placement ◽

3D Printed ◽

Stent Retrievers

Abstract Background The ability of the patient specific 3D printed neurovascular phantoms to accurately replicate the anatomy and hemodynamics of the chronic neurovascular diseases has been demonstrated by many studies. Acute occurrences, however, may still require further development and investigation and therefore we studied acute ischemic stroke (AIS). The efficacy of endovascular procedures such as mechanical thrombectomy (MT) for the treatment of large vessel occlusion (LVO), can be improved by testing the performance of thrombectomy devices and techniques using patient specific 3D printed neurovascular models. Methods 3D printed phantoms were connected to a flow loop with physiologically relevant flow conditions, including input flow rate and fluid temperature. A simulated blood clot was introduced into the model and placed in the proximal Middle Cerebral Artery (MCA) region. Clot location, composition, length, and arterial angulation were varied and MTs were simulated using stent retrievers. Device placement relative to the clot and the outcome of the thrombectomy were recorded for each situation. Digital subtraction angiograms (DSA) were captured before and after LVO simulation. Recanalization outcome was evaluated using DSA as either ‘no recanalization’ or ‘recanalization’. Forty-two 3DP neurovascular phantom benchtop experiments were performed. Results Clot angulation within the MCA region had the most significant impact on the MT outcome, with a p-value of 0.016. Other factors such as clot location, clot composition, and clot length correlated weakly with the MT outcome. Conclusions This project allowed us to gain knowledge of how such characteristics influence thrombectomy success and can be used in making clinical decisions when planning the procedure and selecting specific thrombectomy tools and approaches.

Download Full-text

Low-cost, monolithically 3D-printed, miniature high-flow rate liquid pump

Journal of Physics Conference Series ◽

10.1088/1742-6596/1407/1/012040 ◽

2019 ◽

Vol 1407 ◽

pp. 012040

Author(s):

Anthony P Taylor ◽

Luis F Velásquez–García

Keyword(s):

Flow Rate ◽

Low Cost ◽

High Flow ◽

High Flow Rate ◽

3D Printed ◽

Liquid Pump

Download Full-text

Design and Simulation of the Hydraulic System for the Disc Cutter of the Rock Hob Test-Bed

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.499.51 ◽

2012 ◽

Vol 499 ◽

pp. 51-55

Author(s):

Yu Hou Wu ◽

Jian Sun ◽

Hong Sun ◽

Albert J. Shih ◽

X.Q. Zhao

Keyword(s):

Flow Rate ◽

Hydraulic System ◽

Tunnel Boring Machine ◽

Vertical Movement ◽

Movement Speed ◽

Disc Cutter ◽

Test Bed ◽

Hydraulic Oil ◽

Tunnel Boring ◽

Rock Tunnel

Rock tunnel boring machine is one of the main machineries and equipments for underground engineering, and the failure of its disc cutter is the main failure form of this machinery. The experiment on the failure and wear of the disc cutter is difficult. In this paper, a rock hob test-bed is designed, and the hydraulic-driven system of its disc cutter of rock hob test-bed is simulated; the effect of load and flow rate of hydraulic oil in this hydraulic system on characteristics of this disc cutter system is analyzed. The results show that the vertical movement speed of disc cutter is directly proportional to the flow rate; the effect of the load on this speed and the vertical pressure can be ignored; the delay time of the movement of the disc cutter to the flow rate of hydraulic oil is proportional to the load. These results are very helpful to the structure optimization of disc cutter system of rock tunnel boring machine and the improvement of working efficiency.

Download Full-text

Preclinical testing platforms for mechanical thrombectomy in stroke: a review on phantoms, in-vivo animal, and cadaveric models

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2020-017133 ◽

2021 ◽

pp. neurintsurg-2020-017133

Author(s):

Yang Liu ◽

Mehdi Abbasi ◽

Jorge L Arturo Larco ◽

Ramanathan Kadirvel ◽

David F Kallmes ◽

...

Keyword(s):

Comprehensive Evaluation ◽

Cerebral Arteries ◽

Patient Specific ◽

Flow Conditions ◽

Vessel Occlusion ◽

Preclinical Testing ◽

Multiple Test ◽

3D Printed ◽

Device Interaction

Preclinical testing platforms have been instrumental in the research and development of thrombectomy devices. However, there is no single model which fully captures the complexity of cerebrovascular anatomy, physiology, and the dynamic artery-clot-device interaction. This article provides a critical review of phantoms, in-vivo animal, and human cadaveric models used for thrombectomy testing and provides insights into the strengths and limitations of each platform. Articles published in the past 10 years that reported thrombectomy testing platforms were identified. Characteristics of each test platform, such as intracranial anatomy, artery tortuosity, vessel friction, flow conditions, device-vessel interaction, and visualization, were captured and benchmarked against human cerebral vessels involved in large-vessel occlusion stroke. Thrombectomy phantoms have been constructed from silicone, direct 3D-printed polymers, and glass. These phantoms represent oversimplified patient-specific cerebrovascular geometry but enable adequate visualization of devices and clots under appropriate flow conditions. They do not realistically mimic the artery-clot interaction. For the animal models, arteries from swine, canines, and rabbits have been reported. These models can reasonably replicate the artery-clot-device interaction and have the unique value of evaluating the safety of thrombectomy devices. However, the vasculature geometries are substantially less complex and flow conditions are different from human cerebral arteries. Cadaveric models are the most accurate vascular representations but with limited access and challenges in reproducibility of testing conditions. Multiple test platforms should be likely used for comprehensive evaluation of thrombectomy devices. Interpretation of the testing results should take into consideration platform-specific limitations.

Download Full-text

Design and Simulation of the Hydraulic System for the Rock Hob Test-Bed

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.146-147.565 ◽

2010 ◽

Vol 146-147 ◽

pp. 565-570

Author(s):

Jian Sun ◽

De Hong Zhao ◽

Hong Sun ◽

Yu Hou Wu ◽

Peng Zhou ◽

...

Keyword(s):

Flow Rate ◽

Hydraulic System ◽

Test Bench ◽

Tunnel Boring Machine ◽

Movement Speed ◽

Test Bed ◽

Underground Engineering ◽

Tunnel Boring ◽

Driven System ◽

Rock Tunnel

Rock tunnel boring machine is one of the main machineries and equipments for underground engineering ,and the failure of tool systems is the main failure form of this machinery. Rock hob test-bed is the only testing equipment for tool failure and wear. In this paper, the hydraulic-driven system of the rock hob test bench is designed and simulated, and the effect of load and flow rate of hydraulic oil in this hydraulic system on characteristics of this test-bad is analyzed. The results show that the horizontal movement speed of test bench is directly proportional to the flow rate, but the effect of the load on this speed can be ignored; the delay of the movement of the test bench are proportional to the load. These results are very helpful to the structure optimization of tool system and the improvement of working efficiency.

Download Full-text

Revascularization and functional outcomes after mechanical thrombectomy for acute ischemic stroke in elderly patients

Journal of Neurosurgery ◽

10.3171/2018.12.jns182399 ◽

2020 ◽

Vol 132 (4) ◽

pp. 1182-1187 ◽

Cited By ~ 1

Author(s):

Carrie E. Andrews ◽

Nikolaos Mouchtouris ◽

Evan M. Fitchett ◽

Fadi Al Saiegh ◽

Michael J. Lang ◽

...

Keyword(s):

Ischemic Stroke ◽

Elderly Patients ◽

Acute Ischemic Stroke ◽

Mechanical Thrombectomy ◽

Multivariate Logistic Regression Analysis ◽

Standard Of Care ◽

Stroke Severity ◽

Vessel Occlusion ◽

Younger Patients ◽

Success Of Treatment

OBJECTIVEMechanical thrombectomy (MT) is now the standard of care for acute ischemic stroke (AIS) secondary to large-vessel occlusion, but there remains a question of whether elderly patients benefit from this procedure to the same degree as the younger populations enrolled in the seminal trials on MT. The authors compared outcomes after MT of patients 80–89 and ≥ 90 years old with AIS to those of younger patients.METHODSThe authors retrospectively analyzed records of patients undergoing MT at their institution to examine stroke severity, comorbid conditions, medical management, recanalization results, and clinical outcomes. Univariate and multivariate logistic regression analysis were used to compare patients < 80 years, 80–89 years, and ≥ 90 years old.RESULTSAll groups had similar rates of comorbid disease and tissue plasminogen activator (tPA) administration, and stroke severity did not differ significantly between groups. Elderly patients had equivalent recanalization outcomes, with similar rates of readmission, 30-day mortality, and hospital-associated complications. These patients were more likely to have poor clinical outcome on discharge, as defined by a modified Rankin Scale (mRS) score of 3–6, but this difference was not significant when controlled for stroke severity, tPA administration, and recanalization results.CONCLUSIONSOctogenarians, nonagenarians, and centenarians with AIS have similar rates of mortality, hospital readmission, and hospital-associated complications as younger patients after MT. Elderly patients also have the capacity to achieve good functional outcome after MT, but this potential is moderated by stroke severity and success of treatment.

Download Full-text