It is well know that warfarin is a risk factor for calciphylaxis. Most of the patients on HD that require anticoagulation are on warfarin. Given the risk of calciphylaxis, the concept of changing over to a factor Xa inhibitor was used in this study to see if that be used for replacement of warfarin. It was a retrospective study at a single center and they found 20 patients who were on dialysis who were on apixaban following a diagnosis of calciphylaxis. 27% of the drug is renally excreted and hence not a bad choice for an ESRD patient.with calciphylaxis who require anticoagulation.
There are although no trials of this agent on ESRD on dialysis and specifically not in calciphylaxis patients. A large retrospective trial did show that use of apixaban compared to warfarin was associated with less bleeding in ESRD patients and less stroke risk and mortality with 5mg BID dosing.
While the study really highlighted that the switch from warfarin to apixaban was ok and there were no significant bleeding and clotting episodes, there were some additional surprise findings. What was surprising to me was that the majority of the patient got better with their calciphylaxis part. The cohort that got apixiban had a lower mortality compared to the established published rates of patients with calciphylaxis not on apixiban.
Have the investigators just stumbled upon a potential treatment for this deadly disease? Given calciphylaxis has a component of TMA and having them on an anticoagulant that doesn’t inhibit vitamin K might be beneficial. The question remains that would you start apixiban in someone with calciphylaxis who was not on anticoagulation?