Engineers in robotics are concerned with matters of the heart.

 

A multidisciplinary team of robotics and electronic systems engineers collaborated with cardiologists and materials scientists to develop a robotic apparatus that precisely and remotely controls guidewires through tiny and tortuous blood vessels using an external magnetic field. The findings were published in the journal Advanced Healthcare Materials by a team led by researchers at Daegu Gyeongbuk Institute of Science and Technology (DGIST).

Following further testing and commercialization, the apparatus could reduce physicians' exposure to X-ray radiation while searching for and treating narrowed or blocked blood vessels.

"Cardiovascular diseases are the leading cause of death worldwide, and it is critical to be able to diagnose and treat these diseases in the least invasive way possible," says Hongsoo Choi, DGIST robotics engineer.

Percutaneous coronary intervention (PCI) currently entails inserting a guidewire through the large femoral artery in the groin or the radial artery in the wrist and expertly manipulating it until it reaches the aorta, the body's largest blood vessel. The aorta is then injected with a contrast agent, which spreads into the coronary arteries that supply the heart. Following that, X-ray images are taken to identify any blockages in these arteries. This intervention is extremely difficult and can still result in vessel perforation. It also exposes the physician to unnecessary X-ray radiation because the procedure is performed at the patient's bedside.

Researchers have been looking into the use of robotic magnetic systems to improve remote control of this type of procedure in recent years. However, the systems that have been developed are frequently large and slow to respond.

Choi and his colleagues have now developed a system for remotely controlling a magnetically steerable microrobotic guidewire using a controllable external magnetic field. A system of eight electromagnets arranged in a hemispherical configuration beneath a surgical bed generates the field. The patient will be positioned on a bed, with the guidewire inserted into an artery and remotely guided by changing the magnetic field. The guidewire is constructed of a biocompatible silicone tube that can move through blood vessels with minimal surface friction. For magnetic steering, the tip of the microrobotic tube contains a neodymium-iron-boron permanent magnet and hard-magnetic composites.

The system was first tested using 2D and 3D-printed blood vessel models by the researchers. They then put it to the test in anesthetized pigs, remotely controlling the guidewires through small and tortuous arteries in the pelvis, kidneys, and heart.

"Our proposed electromagnetically controllable microrobotic interventional system (ECMIS) could reduce physician radiation exposure by allowing them to perform the procedure remotely in an X-ray shielded control booth using low-strength magnetic fields," says Choi. "It also does not necessitate the extensive training required for conventional PCIs."

More tests and improvements are needed, but the researchers are already planning to modify their apparatus to target vessels in the nervous system and lungs.