Empiric tPA: A Salvage Therapy for Severe Frostbite of the Upper Extremity

Purpose

Severe frostbite of the upper extremity is a devastating disease process. Historically, this has been managed expectantly with a digit amputation rate of 50%(1). Over the last 10 years, strategies have emerged to improve frostbite care including the use of thrombolytic therapy. Unfortunately, these protocols are often delayed by the use of angiography and nuclear medicine bone scans (2). We sought to determine the utility and digit salvage rate of empiric thrombolytic therapy for severe frostbite of the upper extremity.

 

Materials and Methods

We reviewed patients who presented with frostbite of the upper extremity to the Burn Institute at Akron Children’s Hospital. Six patients were identified who received empiric thrombolytic therapy immediately after rewarming. Regimen includes intravenous tPA bolus and infusion after rewarming followed by 2 weeks of therapeutic low molecular weight heparin (enoxaparin). All patients were evaluated at outpatient for a minimum of 6 weeks to determine the need for amputation. We collected digit involvement, patient demographics, complications from tPA, and the need for digit amputation. We utilized a historic group of expectantly managed frostbite patients as a control group. ANOVA and fisher’s exact test were used for all analysis.

 

Results

All 6 patients successfully completed the thrombolytic protocol. There were no significant differences between the tPA group and our historic group. A total of 60 digits were involved with severe frostbite (grade III or IV frostbite) in the tPA cohort. Of the 60 digits involved, 46 digits were salvaged at 6 week follow up. The tPA group had a significantly higher digit salvage rate than our expectant control group (50% vs 77% p<0.01). There were no life threatening complications from tPA including intracranial hemorrhage or transfusion. One patient did spontaneously bleed from small abrasions that required intervention, but the patient was able to complete the tPA protocol.

 

Conclusion

Our experience shows that there is a potential for high success rate of digit salvage when empiric tPA is used. In an appropriately selected group with severe frostbite, additional imaging or angiography has the potential to delay patient care. If eligible, we recommend the use of tPA at presentation without the use of pretreatment nuclear medicine imaging or angiography.

(1): Nygaard RM, Whitley AB, Fey RM, Wagner AL. The Hennepin Score: Quantification of Frostbite Management Efficacy. J Burn Care Res. 2016 Jul-Aug;37(4):e317-22.

(2) Jones LM, Coffey RA, Natwa MP, Bailey JK. The use of intravenous tPA for the treatment of severe frostbite. Burns. 2017 Aug;43(5):1088-1096.