Bleeding risk assessment in immune thrombocytopenia

Abstract

The bleeding risk in immune thrombocytopenia (ITP) is related not only to low platelet count but also to the presence of platelet dysfunction. However, diagnosing a concomitant platelet dysfunction is challenging as most of the available platelet function assays (PFAs) require a platelet count of greater than 100,000/μL. Sonoclot coagulation and platelet function analyzer works on the principle of viscoelastometry, and results remain unaffected by the platelet counts. To assess the platelet function in adult acute ITP patients with the help of sonoclot coagulation and platelet function analyzer and correlate it with the risk of bleeding. Newly diagnosed acute ITP patients with a platelet count less than 20,000/μL were divided into two groups based on WHO bleeding grade: ITP non-bleeder (ITP-NB) group (WHO bleeding grade ≤1) and ITP bleeder (ITP-B) group (WHO bleeding grade ≥2). Platelet function was assessed by sonoclot in both groups. The patients without significant bleeding (ITP-NB) were followed up monthly for six months with the assessment of platelet function during each contact. Eighty patients (30 ITP-B and 50 ITP-NB) were prospectively included in this study. The median age of patients in the two groups was 37 years and 30 years, respectively. The female-to-male ratio was 4:1 and 1:1 in ITP-B and ITP-NB groups. The median platelet count in ITP-B and ITP-NB was 12000/μL (range 1000-19000/μL) and 8000/μL (range 1000-19000/μL), respectively. Mean platelet functions by sonoclot in both groups were lower than the normal cut-off (>1.6). However, the mean platelet function in the ITP-B group (0.2 + 0.17) was significantly lower than the ITP-NB group (1.2 ± 0.52) (p = 0.01). During the follow-up period of 6 months, patients in ITP-NB with a normal platelet function (>1.6) on sonoclot had lesser episodes (one episode) of clinically significant bleeding than patients with a low platelet function (4 episodes). Patients with acute severe thrombocytopenia and bleeding phenotype have a greater abnormality on platelet function by sonoclot than patients with non-bleeding phenotype. This information may help in taking therapeutic decisions in patients with acute ITP.

Keywords: Bleeding Disorder; Bleeding Risk; ITP; Immune Thrombocytopenia; Platelet Dysfunction; Sonoclot; Thrombocytopenia.