Thrombotic thrombocytopenic purpura secondary to ABO group incompatible blood transfusion in a patient after cardiac surgery

Successful treatment of plasma exchange-refractory thrombotic thrombocytopenic purpura with rituximab: A case report

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP), a subtype of thrombotic microangiopathy, has a very high fatality rate if there is no timely diagnosis or treatment. Here, we report a case of TTP refractory to high displacement plasma exchange, which was later successfully treated with rituximab.

CASE SUMMARY

Here we report a case of refractory TTP in a 63-year-old woman with a low platelet count and decreased ADAMTS13 activity. Her platelet count was 9 × 10⁹/L, hemoglobin level was 81 g/L, and ADAMTS13 was < 5%. She was diagnosed with thrombotic thrombocytopenic purpura. After 8 d of daily plasma exchange (PEX), her platelet levels were still low. However, after 6 d of treatment with rituximab, her platelet count increased and ADAMTS13 activity returned to normal.

CONCLUSION

PEX can cure most patients, but the relapse rate can be up to 50%-60%. This case suggested that rituximab can improve the curative efficiency of PEX and prevent disease relapse in TTP.

Postsurgical thrombotic microangiopathy: Case series and review of the literature

OBJECTIVES

Describe the clinical presentation, treatment, and outcomes of postsurgical thrombotic microangiopathy (TMA).

METHODS

In this retrospective study, records of individuals diagnosed with TMA developing within 30 days of a surgical procedure at Mayo Clinic from 2000 to 2016 were reviewed. Available literature regarding postsurgical TMA was comparatively reviewed.

RESULTS

Twenty patients were diagnosed with TMA developing within 30 (median 6.5, range (1-28)) days) following a procedure. Preceding procedures included orthopedic (n = 4), vascular (n = 4), abdominal (n = 8), thoracic (n = 2), and other (n = 2). Review of the literature identified 65 patients with postsurgical TMA and cardiovascular procedures were the most common preceding surgery. The majority of patients in the current cohort and literature were treated with therapeutic plasma exchange (TPE). Among the evaluable patients in the current cohort, 100% demonstrated response to TPE; however, 25% required the addition of other therapy including eculizumab to maintain a response 80% of patients in the literature demonstrated a response to TPE.

CONCLUSIONS

Although rare, early recognition and treatment of postsurgical TMA can lead to good outcomes. More research is necessary to determine the underlying pathophysiology and optimal treatment for postsurgical TMA.

Recombinant ADAMTS-13: first-in-human pharmacokinetics and safety in congenital thrombotic thrombocytopenic purpura

Safety, tolerability, and pharmacokinetics of recombinant ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13; BAX 930; SHP655) were investigated in 15 patients diagnosed with severe congenital ADAMTS-13 deficiency (plasma ADAMTS-13 activity <6%) in a prospective phase 1, first-in-human, multicenter dose escalation study. BAX 930 was well tolerated, no serious adverse events occurred, and no anti-ADAMTS-13 antibodies were observed. After single-dose administration of BAX 930 at 5, 20, or 40 U/kg body weight to adolescents and adults, there was approximate dose proportionality with respect to maximum plasma concentration (C_max [U/mL]) and area under the concentration-time curve (AUC [h∙U/mL]). Dose-related increases of individual ADAMTS-13:Ag and activity were observed and reached a maximum within 1 hour. With escalating BAX 930 doses administered, a dose-dependent persistence of ADAMTS-13-mediated von Willebrand factor (VWF) cleavage products and reduced VWF multimeric size were observed. This study demonstrated that pharmacokinetic parameters of BAX 930 were comparable to those estimated in previous plasma infusion studies and provided evidence of pharmacodynamic activity. This study was registered at www.clinicaltrials.gov as #NCT02216084.