As a neurosurgeon forthe past three decades, I have witnessed thousands of patients who had suffered from the aftermaths of stroke. It is very sad to see them being crippled,failure to swallow and loss of mental functions. Fortunately, for the lastdecade, new hopes were kindled by the use of transcatheter endovascular treatment method in treating this deadly disease. Many new devices such asstent and retriever are emerging on the market for either retrieving the clotor removing the clot from a blocked vessel by suction. However, the effectiveness of these new devices are not well accepted and established.Six years ago, I was fortunate to have the opportunity of meeting with the engineer academia at HKUST. I posted the problems of the flow dynamic change inside the diseasedn blood vessel and the possible ways of treatment of stroke to them. They immediately felt very interested and would like to take up the challenge. Forthe first time, the clinician is managing to collaborate with a group ofscientists and mechanical engineers in solving clinical problems, which is rare in Hong Kong. This collaboration provides us an opportunity to become a center to integrate advanced research, education, clinical application, and entrepreneurship for the benefit of the people with stroke. .
To start off the project, we started to build an ex vivo vascular model using human placenta at Kwong Wah Hospital to test various stentrievers on the Market five years ago.The result was astonishing as the current devices that we are using have many shortcomings. The devices exert frictional force on the endothelium of the blood vessel wall that can cause bleeding. Furthermore, the clot is fragmentedon retrieval and disseminating smaller clots to distal vessels. From these important observations, our PhD students have come up with some innovative ideas to improve the mechanism of clot retrieval and prevention of clot fragmentation. Radiofrequency inducing clot adhesion was suggested. In the past two years, we have been using standard clot sample harvested from human blood to test for the correct radiofrequency and timing of clot adhesiveness in vitro. Last few months, we have obtained very positive results that radiofrequency can work for clot retrieval and is safe. The prototype is completed and ready for animal testing before human trials.
Building an ex vivo placenta vascular model with pulsating blood flow
The placenta is a living organ immediately after child delivery. It will be ideal to reperfuse the tissue with blood and keep the tissue alive as long as 6 hours. With the appropriate setup, it will be be an ideal vascular model to test intra-vascular devices such as stent, platinum coils and stentrievers for treatment of stroke.