Improving Outcomes, Mythbusting, Radiology

Keep those toes warm with tPA!

A graduate student decided to go out and celebrate after doing well on an exam.  After being unable to locate a designated driver, and having their iPhone run out of battery rendering them without Uber to locate a taxi, they decided to sleep in their car for a few hours.  Unfortunately, it was bitterly cold out that evening.  After waking up several hours later and returning home, the patient was unable to rewarm their feet despite earnest attempts.  They began to notice blisters on their feet, and then proceeded to the nearest Emergency Department for further care, where the astute provider diagnosed the patient with advanced frostbite and began making phone calls.

Are there any non-surgical interventions that may help?

In a 2005 publication, 19 patients with severe frostbite received tPA (6 of which received it intra-arterially) in addition to heparin.  These patients had not improved with rapid rewarming and had absent doppler pulses in the distal limb or digits, and no perfusion by technetium scan.  Historical data suggested that 174 digits in these 19 patients were at risk for amputation, yet only 33 were amputated.  Poor response was noted in those with >24hrs of cold exposure, warm ischemia >6hrs, or evidence of multiple freeze/thaw cycles. 

 

In a 2007 publication of a single center study, patients with frostbite from 1995-2006 that were not treated with tPA were compared to patients who were treated with tPA from 2001-2006. 

 

The data:

6 tPA treated patients, encompassing 13 extremities
26 non tPA treated patients , encompassing 57 extremities.

Percentage of extremities requiring an amputation
tPA treated patients – 23%
non-tPA treated patients 55 %

Percentage of patients requiring a digital amputation:
tPA treated patients – 23%
non-tPA treated patients – 29%

Percentage of patients requiring a proximal amputation:
tPA treated patients – 0%
non-tPA treated patients 25% (about a third of which were below knee amputations)

one of the tPA treated patients developed a retroperitoneal hematoma that resolved spontaneously without intervention. 

While these are single center studies, and not truly blinded, I think that they provide a reasonable basis to attempt tPA if you have an IR capable institute – or make a reasonable argument to transfer to an institute that does.  There seems to be at least a 50% decrease in the number of surgical procedures performed  and a decrease in the size of area to be amputated.  It is certainly worth mentioning to the admitting surgical team.  Drop the bug in their ear, and the data suggests a strong chance that you’ll save a limb.

Stay warm out there.  

 

 

PMID: 16394908
PMID: 17576891

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