An anti-clotting drug used to treat strokes and heart attacks can also restore blood flow to frostbitten fingers and limbs, greatly reducing the need for amputation, according to a new study.

Doctors at the University of Utah who conducted the research on a small sample of patients hope it marks the start of a move beyond the traditional — and limited — treatment for frostbite.

"What it does is help to rescue that tissue that is damaged but not yet dead," said Dr. Stephen Morris, one of the authors of the study, which was released Monday in the Archives of Surgery medical journal.

Patients who received the thrombolytic therapy at the university's burn center were more likely to keep their frostbitten fingers and toes than patients who went without the drug.

All patients had similar degrees of frostbite.

Thrombolytic therapy is not new, but has been difficult to study because not every frostbite victim is a candidate. For instance, people already on blood thinners or someone who has suffered a head injury would be at risk for serious complications from the anti-clotting drug.

Dr. John Twomey, burn director at the Hennepin County Medical Center in Minneapolis, first tried the therapy on a patient about 20 years ago and has treated 18 other patients with it since.

Twomey, whose early findings are mentioned in the Utah study, said the treatment for frostbite has been limited to warming the affected tissue and waiting to see how much would survive.

"We saw all these frostbitten patients come in, and there was absolutely nothing we could do to alter their disease," Twomey said. "That was pretty discouraging and disheartening to see that happening, and it happened repeatedly."

In the Utah study, six patients who were treated with a drug called tissue plasminogen activator, or tPA, within 24 hours of injury were compared with 25 other patients who did not receive the drug, and one patient who got the anti-clotting drug later than the 24-hour window.

Among the patients who received tPA within 24 hours, only six of 59 frostbitten fingers or toes were removed, or about 10 percent. In the other group, 97 of 234 affected digits were amputated, or about 41 percent.

The sample used for the study was small and taken only from one geographic area. The study was also based only on the one anti-clotting drug. Those are just a few of the variables that leave questions to be answered by future research.

But for some, the findings may offer a chance at avoiding amputation.

"For the injured tissue, there's still hope," said Dr. Amalia Cochran, another of the University of Utah authors.