One of the holy grails of surgery is to “get in and get out” with minimal blood loss. This is especially difficult to do in the case of vascular surgery, which often requires re-anastomosing two or more blood vessels together (e.g. in order to create a bypass or transplant an organ). Blood loss is not only detrimental to the patient, but also obscures the surgical field – which actually can also be bad for the patient. Hence, surgeons currently use clamps and elastic loops to block blood flow through the vessel they are working on. However, these tools can often themselves damage weak blood vessels due to their clamping pressure.
A solution in the form of a gel polymer has just been approved by the FDA. Developed by PluroMed Inc., LeGoo is a thermosensitive, reversible polymer that is liquid at room temperatures and solid at higher temperatures. (Wait, isn’t that contrary to everything you learned about phase transitions in high school? Fortunately emerging medical technologies often supersede the rules taught in intro science classes!).
According to the FDA press release:
When injected into a blood vessel, LeGoo forms a gel plug that molds to the shape of the blood vessel and stops blood flow for up to 15 minutes.
After the blood vessels are joined, the plug is expected to dissolve on its own in 15 minutes. In the event the plug needs to dissolve sooner, the surgeon can dissolve the gel plug by applying a cold pack or cold saline to the blood vessel.
In support of approval of the pre-marketing application, the FDA reviewed studies showing that LeGoo is biocompatible and non-toxic. The FDA also looked at data from a clinical trial of 110 patients undergoing bypass surgery without stopping the heart (off pump coronary artery bypass). Investigators found that LeGoo is as safe and effective as vessel loops, devices commonly used to stop blood flow during coronary bypass surgery.
LeGoo is approved for temporarily stopping blood flow in blood vessels below the neck that are 4 millimeters or less in diameter. It is contraindicated for use on vessels supplying blood to the brain.
There is a description and animation of the technology behind LeGoo on the company’s website. You can also watch the YouTube video below showing an actual application of LeGoo in surgery.
Press release: FDA approves gel to stop blood flow during blood vessel surgery
Product page: LeGoo Internal Vessel Occluder
