Splenectomy for immune thrombotic thrombocytopenic purpura (iTTP): a systematic review and meta-analysis.

Background: Immune thrombotic thrombocytopenic purpura (iTTP) is a thrombotic microangiopathy caused by autoantibody-mediated ADAMTS13 deficiency. Historically, splenectomy was used for multiply relapsing iTTP in clinical remission to lessen risk of relapse and as treatment for plasma-refractory or plasma-dependent iTTP.

Methods: We conducted a systematic review and meta-analysis on two questions related to splenectomy for iTTP: (1) In patients with relapsing iTTP, what is the effect of splenectomy on iTTP relapse rate? (2) In patients with plasma-refractory or plasma-dependent iTTP, what proportion of patients achieve clinical remission after splenectomy? Three electronic databases (Embase, PubMed, Scopus) were searched for keywords related to TTP and splenectomy, and screening was completed following PRISMA guidelines.

Results: Twenty-three studies were included, representing 62 patients (205.8 years of follow-up) who underwent splenectomy for relapsing iTTP and 57 patients (173.9 years of follow-up; not reported in 3 studies) who underwent splenectomy for plasma-refractory/dependent iTTP. In patients who underwent splenectomy for relapsing iTTP, there were 1.80 (95% confidence interval [CI], -2.66 - -0.95) fewer iTTP episodes annually after compared to before splenectomy. For patients who underwent splenectomy for plasma-refractory/dependent iTTP, the proportion of patients achieving clinical remission was 0.87 (95% CI, 0.76 - 0.93). Only two studies included any patients who received rituximab.

Conclusion: There is low quality evidence to support the use of splenectomy for multiply relapsing iTTP to decrease relapse rate and for plasma-refractory/dependent iTTP to achieve remission, noting that most of the evidence precedes the routine use of rituximab in iTTP.