With subtle symptoms that are easy to miss, hypertension often goes unnoticed. For those with resistant hypertension, it's not just hard to spot—it's hard to treat. Despite taking multiple medications, their blood pressure remains stubbornly high, raising the risk of serious health issues.
In such cases, clinicians turn to interventions like renal denervation (RDN), a minimally invasive procedure that lowers blood pressure by targeting the nerves around the kidneys. Guided by temperature feedback, ablation electrodes disrupt these nerves, effectively reducing signalling and lowering blood pressure.
Ming-Yuan Cheng, Head of the MedTech Department at A*STAR’s Institute of Microelectronics (IME) explained that current RDN catheters lack a precise force feedback system, making it difficult for surgeons to accurately assess the contact between the ablation electrodes and the artery walls.
“Without precise feedback, there’s a risk of under ablation, making the treatment ineffective, or over ablation which can damage the tissue,” said Cheng.
The IME researchers teamed up with a group from Kalos Medical in South Korea to improve the effectiveness and safety of RDN procedures.
Concept of an RDN procedure using a catheter with Cheng and colleagues’ sensor device. (a) Insertion of the catheter into the renal arteries. (b) Schematic of the RDN catheter when activated in a renal artery for nerve ablation. (c) Schematic of the RDN device sensor module’s stacked structure.
© A*STAR Research
Cheng outlined the major challenges in the RDN catheter design, starting with device miniaturisation. “The RDN catheter is inserted into the renal artery and has to be under 2 mm in diameter,” Cheng said. The second challenge was that movement during the procedure can cause interference, making the force sensor readings inaccurate when the catheter expanded to contact the renal artery.
To address this, the team developed a catheter with three deployable spines, each equipped with sensors for temperature, contact force and ablation power feedback. The sensors included a platinum-based temperature sensor, a radio frequency (RF) ablation electrode, and a contact force sensor—all designed to work together seamlessly during the RDN procedure.
Lab and simulated tests were conducted to assess how well their device worked in both controlled settings and conditions that mimic the human body. They found that their system improved ablation precision with real-time feedback, enhanced safety by preventing overheating and remained reliable through repeated use.
With a patent on their innovation secured, the team’s research is now advancing towards clinical trials. According to Cheng, several animal trials have already been conducted in Singapore, which have validated the biosafety and efficacy of the sensor device. Additionally, a total of 30 assembled catheters have been provided to collaborators in South Korea for upcoming clinical trials.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Microelectronics (IME).
