As a less invasive alternative to open-heart surgery, cardiac surgeons are increasingly accessing the heart from within using central venous catheters. An experimental new catheter could soon make such procedures quicker and easier than ever before.
Ordinarily when using a central venous catheter for heart surgery, the device is inserted into a vein in the patient's neck, chest, arm or groin via a small incision.
The surgeon then guides the catheter up that vein and into the heart, typically guided by ultrasound images. Once the end of the catheter is inside the heart, a small surgical tool on its tip is used to perform the actual cardiac surgery.
One problem lies in the fact that if the catheter is narrow enough to pass through the veins unimpeded, it's often so small that its tip/tool gets pushed back by the beating heart tissue. This means that extending it into the heart, and remotely manipulating its tip once it's in the organ, can be very difficult.
The new robotic catheter, developed by Prof. Tommaso Ranzani and colleagues at Boston University, is designed to address that issue.
Based on an octopus-inspired device previously created by Ranzani, it incorporates a flexible, inflatable, accordion-bellows-like tip. Immediately behind that tip is a ribbed expandable ring. As the device makes its way through the vein, the tip stays deflated and the ring remains in a narrowed state – so the catheter as a whole is relatively narrow.
Upon reaching the opening to the heart, the ring is expanded, bracing the catheter against the inner walls of the vein. The tip is then inflated, causing it to expand into the heart. Because it becomes thicker and stronger once inflated, it doesn't get knocked around by the beating cardiac tissue.
The prototype has already been utilized to successfully perform two procedures – a pacemaker lead placement and a tricuspid valve repair – on extracted adult pig hearts. In the case of the first procedure, five inexperienced operators were able to do the job in about the same amount of time it took an experienced cardiac surgeon to do so using a standard catheter.
"As we discuss these results with physicians working in the field, we see a high level of enthusiasm and hear of more and more applications for this technology," said Ranzani. "I think generally that this strategy is taking us in the right direction."
You can see the catheter in pig-heart-probing action, in the video below. More complex procedures, performed on live animals, are now being planned.
A paper on the research was recently published in the journal Science Advances.
Source: National Institute of Biomedical Imaging and Bioengineering via Interesting Engineering