Enabling Angioplasty-Ready “Smart” Stents to Detect In-Stent Restenosis and Occlusion

MedicalResearch.com Interview with:

Kenichi Takahata, Ph.D., P.Eng. Associate Professor Department of Electrical & Computer Engineering Faculty of Applied Science University of British Columbia Vancouver, B.C., Canada

Dr. Takahata

Kenichi Takahata, Ph.D., P.Eng.
Associate Professor
Department of Electrical & Computer Engineering
Faculty of Applied Science
University of British Columbia
Vancouver, B.C., Canada

MedicalResearch.com: What is the background for this technology and study? 

Response: Cardiovascular disease (CVD) is the number one cause of mortality globally. One of the most common and proven treatments for CVD is stenting. Millions of stents are implanted annually worldwide. However, the most common complication called in-stent restenosis, re-narrowing of stented arteries, still poses a significant risk to patients.

To address the current lack of diagnostic technology to detect restenosis at its early stage, we are developing “smart” stents equipped with microscale sensors and wireless interface to enable continuous monitoring of restenosis through the implanted stent. This electrically active stent functions as a radio-frequency wireless pressure transducer to track local hemodynamic changes upon a re-narrowing condition. We have reported a new smart stent that has been engineered to fulfill clinical needs for the implant, including its applicability to current stenting procedure and tools, while offering self-sensing and wireless communication functions upon implantation.

The stent here has been designed to function not only as a typical mechanical scaffold but also as an electrical inductor or antenna. To construct the device, the custom-designed implantable capacitive pressure sensor chip, which we developed using medical-grade stainless steel, are laser-microwelded on the inductive antenna stent, or “stentenna”, made of the same alloy. This forms a resonant circuit with the stentenna, whose resonant frequency represents the local blood pressure applied to the device and can be wirelessly interrogated using an external antenna placed on the skin.

MedicalResearch.com: What are the main findings?

Response: The microfabricated prototypes were robust enough to survive through the standard catheter assembly (involving crimping forces of >100 N) and stenting procedures with commercial catheter tools. The adopted microwelding integration method provided clear merits in increasing both mechanical robustness and electrical performance of the device. The gold and Parylene C coatings applied to the device were found to be essential for the designed sensing function in vivo. These coatings also offered biocompatibility and x-ray opacity of the device. Using a swine model, our device was demonstrated to show wireless detection of blood clot formation, as well as real-time tracking of local blood pressure change over a range of 108 mmHg that well covers the range involved in human.

MedicalResearch.com: What should readers take away from your report?

Response: The smart stent prototype devised to fulfill both engineering and clinical requirements has not only proved significantly improved wireless sensing performance but also achieved the device’s compatibility with the standard angioplasty procedure. The latter aspect is a key to bring smart stent technology into market.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: Our future work will involve further refinement of the design and testing of prototypes towards clinical trials. This study could also be extended to other applications for smart medical implants. For example, we are working on an intelligent version of ureteral stent designed to detect obstacles between the kidney and bladder towards prevention of kidney swelling (know as hydronephrosis) and eventual failure.

Disclosures:  This work was partially supported by the Canadian Institutes of Health Research, the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, the British Columbia Knowledge Development Fund, and the CMC Microsystems. The author was supported by the Canada Research Chairs program.

Citation: X. Chen, B. Assadsangabi, Y. Hsiang, K. Takahata, “Enabling Angioplasty-Ready “Smart” Stents to Detect In-Stent Restenosis and Occlusion,” Advanced Science, 5, 2018, 1700560.

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