Using imaging to visualize areas lacking blood flow and deliver drugs via catheter, interventional radiologists are reopening recently frozen, clotted arteries with clot-busting and anti-spasmodic drugs, according to a prospective study released Monday at the Society of Interventional Radiology’s (SIR) 33rd annual scientific meeting.
The study’s participants had severely frostbitten hands and feet (with tissue frozen to the bone and damage occurring deep in muscles, tendons, nerves and blood vessels), which typically leads to gangrene and loss of limbs.
In severe frostbite, the blood vessels are affected and blood flow is blocked. After thawing and re-warming, small clots usually form, according to the researchers. Spasm of the injured arteries further impedes flow to the smallest vessels of the limbs
George R. Edmonson, MD, interventional radiologist with St. Paul Radiology in St. Paul, Minn, and colleagues, said the standard treatment for frostbite—typically involving re-warming the affected area and, in severe cases, amputation—hasn’t changed for decades.
For the study, the interventional radiologists used angiography, an x-ray exam of the arteries and veins, to confirm loss of blood flow to a patients hand or toes, then intra-arterial catheters to directly deliver drugs to dissolve the blood clots and relax the arteries’ muscular walls.
“Previously severe frostbite was a one-way route to limb loss. This treatment is a significant improvement. We’re opening arteries that are blocked so that tissues can heal and limbs can be salvaged. We were able to reopen even the smallest arteries, saving patients’ fingers and toes,” Edmonson said.
Edmonson said that severe frostbite looks like a second degree heat burn with large blisters, but it is actually body tissue that is been frozen and—in severe cases—dead. “For half our patients who received the clot-busting drug Tenectaplase, this technique worked beautifully, saving all fingers, hands, toes and feet that otherwise would have been lost,” said Edmonson
In the small prospective trial, results from six frostbite patients, ages 18–65 years, who received Tenectaplase were compared with 11 individuals who had received Retaplase. The trial was designed to see if the greater plasma stability of Tenectaplase would lead to better results.
“With both groups, approximately 80 percent of the patients’ affected limbs, fingers and toes responded with significant improvement. The treatment has been demonstrated to be safe and beneficial. We will continue research to improve and modify the protocols,” noted Edmonson.
“Overall, in about 80 percent of the cases, it significantly improved patients’ outcomes. Within one to three days of treatment, we saw improvement,” said Edmonson, who has been treating an average of 6–10 frostbite patients each year for the past 10 years. He noted that the patients were followed for six weeks to assess their final outcomes.
“With both groups, approximately 80 percent of the patients’ affected limbs, fingers and toes responded with significant improvement. The treatment [Tenectaplase] has been demonstrated to be safe and beneficial. We will continue research to improve and modify the protocols,” Edmonson concluded.