Technology: Polymer gel keeps arteries open after surgery

 作者:柯状     |      日期:2019-02-28 07:12:04
By JOY FRASCINELLA A biodegradeable hydrogel that turns solid when exposed to light or heat could save the US health care system more than $1 billion and keep patients from returning for uncomfortable treatment. One of the costliest and most common operations performed in the US is angioplasty – the unblocking of arteries, especially the coronary arteries, by inserting a catheter that can be blown up like a balloon. The problem with the technique is that between 30 and 50 per cent of patients suffer from restenosis, in which the arteries begin to block up again. This then requires either an additional angioplasty or bypass surgery. But the new hydrogel is able to keep the arteries open while they heal. And with almost 500 000 angioplasties, each costing about $10 000, performed each year in the US, eliminating just one-third would cut more than $1 billion from the health care bill. A team from the University of Texas at Austin has developed the hydrogel, which consists of 90 per cent water, with polyethylene glycol, lactic acid and acrylate. After a standard angioplasty it is delivered to the treated area by a catheter or needle. Light piped through optical fibres is used to solidify the gel, leaving a slippery surface on the artery walls which prevents platelets, white blood cells and other blood constituents from sticking to it. The polymer provides structural support for the treated arteries, keeping them open until they heal. It is then hydrolysed naturally and absorbed by the body after seven to 10 days. Trials in animals have found that it leaves less scarring than other surgical methods used to keep the arteries open. The polymer is also expected to be useful after obstetric and gynaecological surgery, spinal surgery and appendicectomies. After an appendicectomy it would provide support to keep the intestine open, preventing intestinal walls sticking together, which can be dangerous. One problem that the scientists are addressing is that as the material begins to break down it could create side effects such as inflammation, thrombosis or hypersensitivity. Use of the hydrogel has been licensed to Focal, a company based in Cambridge, Massachusetts, which specialises in biodegradable polymers and ‘minimal invasion’ products. Jeffrey Hubell, one of Focal’s founders, who as a professor at the university helped to invent the gel,