A cross-disciplinary research team from The Chinese University of Hong Kong (CUHK) has developed a groundbreaking sub-millimeter Magnetically Actuated Soft Rotatable-tipped Microcatheter (MSRM) that promises to revolutionize treatment for acute ischemic strokes. The novel device addresses critical limitations in current stroke intervention tools, offering a faster, safer, and more precise solution for treating life-threatening blood vessel blockages in the brain.
The research findings, published in the international journal Science Advances, come at a crucial time as stroke remains a leading cause of death and long-term disability worldwide. Research shows that every minute saved between stroke onset and treatment can translate into an extra week of healthy life, making rapid intervention critical.
Addressing Critical Treatment Gaps
Current stroke treatment faces significant challenges, particularly for distal-to-medium vessel occlusions (DMVOs), which are estimated to account for 25% to 40% of acute ischemic strokes. Existing treatment options, such as intravenous thrombolysis and mechanical thrombectomy, have limited effectiveness for these smaller, more distal vessels due to procedural risks and difficulty in achieving full reperfusion.
Traditional stroke intervention requires arterial access through a limb, followed by navigation of guidewires and catheters through the cerebral vasculature. The interventionalist manipulates these devices externally by rotating the guidewire, but the passive transmission of rotational force through narrow, tortuous vessels often leads to slow and imprecise device control, which can compromise patient outcomes.
The single-function design of current devices necessitates frequent tool exchanges, increasing the risk of losing distal vascular access during procedures. Additionally, the limited ability of guidewires and catheters to negotiate sharp turns in complex vascular anatomy raises the risk of vessel wall injury, potentially resulting in cerebral hemorrhage or dissection.
Revolutionary Magnetic Navigation Technology
The MSRM represents a paradigm shift in stroke intervention technology. Measuring between 0.5 mm to 0.9 mm in diameter, the soft-tipped microcatheter is designed specifically for navigating complex vascular pathways and performing multiple treatment functions simultaneously.
"The MSRM features a soft, rotatable tip that can be guided wirelessly using external magnetic fields, which enables precise navigation through complex blood vessels," explained Professor Zhang Li from the Department of Mechanical and Automation Engineering at the Faculty of Engineering. "Once it reaches the blockage, the MSRM can directly deliver clot-dissolving drugs, mechanically break down the clots, and safely retrieve clot debris. This all-in-one design eliminates the need for tool exchanges, reduces procedural risks, and significantly enhances treatment efficiency."
Enhanced Safety Profile
The device's safety advantages are particularly noteworthy. Unlike conventional tools, the MSRM's soft silicone-based tip and low rotation speed of 2-8 Hz minimize trauma to delicate brain vessels. Professor Thomas Leung Wai-hong, Lee Quo Wei Professor of Neurology and Head of the Division of Neurology in the Department of Medicine and Therapeutics at CU Medicine, highlighted the device's superior safety profile.
"In tests using human placenta blood vessels, which closely resemble cerebral arteries, the MSRM showed minimal cell damage compared to the notable vessel wall damage caused by traditional guidewires," Professor Leung noted. "This novel device addresses key limitations in current stroke interventions and offers hope for better stroke treatment."
Clinical Validation and Future Applications
The MSRM has undergone successful validation in both in vivo rabbit models and ex vivo human placenta vessels, demonstrating strong potential for future clinical application. Professor Tony Chan Kai-fung, Research Assistant Professor of the Chow Yuk Ho Technology Centre for Innovative Medicine at CU Medicine, emphasized the device's particular promise for challenging cases.
"The team envisions that this invention offers new hope for DMVO stroke patients, for whom current clot-busting procedures have not proven beneficial, partly due to the risk of complications," Professor Chan commented.
The development comes as the research team calls on the public to strictly manage stroke risk factors and adopt healthy lifestyles, noting that stroke, regardless of whether the vessel occlusion is in large or distal-to-medium vessels, may result in severe disability or death if not treated promptly and effectively.
