Centrifugation-based plasma exchange overcomes blood flow restriction to rescue hyperviscosity syndrome in IgM-κ multiple myeloma: a case report.

When blood flow cannot be raised to the 150-200 mL/min threshold required for membrane-based therapeutic plasma exchange, centrifugation-based therapeutic plasma exchange represents the only mechanistically viable option-yet this specific clinical scenario has not been reported. We describe an 86-year-old man with IgM-κ multiple myeloma who developed hyperviscosity syndrome. Sequential membrane-based approaches failed owing to blood flow restriction: double-filtration plasmapheresis was discontinued when secondary membrane pressure reached 277 mmHg, and membrane-based therapeutic plasma exchange achieved only a 20.1% IgM level reduction at a subtherapeutic flow of 45-60 mL/min. Centrifugation-based therapeutic plasma exchange, operable at 10-150 mL/min, was performed in two sessions via bilateral peripheral antecubital venous access using fresh frozen plasma, achieving IgM level reductions of 67.3 and 66.2% with prompt symptomatic relief and no serious adverse events. Diagnosis of IgM-κ multiple myeloma was established by absence of the MyD88 L265P mutation and presence of t(11;14) on bone marrow cytogenetics. The patient was discharged on lenalidomide plus dexamethasone, with no hyperviscosity syndrome recurrence at follow-up. To our knowledge, this is the first reported case in which centrifugation-based therapeutic plasma exchange served as rescue therapy in a patient for whom blood flow restriction rendered membrane-based modalities non-functional-a clinical niche not addressed in prior comparative studies.