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The story of the discovery of aspirin stretches back more than 3500 years to when bark from the willow tree was used as a pain reliever and antipyretic. It involves an Oxfordshire clergyman, scientists at a German dye manufacturer, a Nobel Prize-winning discovery and a series of pivotal clinical trials. Aspirin is now the most commonly used drug in the world. Its role in preventing cardiovascular and cerebrovascular disease has been revolutionary and one of the biggest pharmaceutical success stories of the last century.

The cornerstone of life-saving therapy in immune mediated thrombotic thrombocytopenic purpura (iTTP) has been plasma exchange (PEX) combined with immunomodulatory strategies. Caplacizumab, a novel anti-von Willebrand factor nanobody, trialled in two multicentre, randomised-placebo-controlled trials leading to EU and FDA approval, has been available in the UK through a patient-access scheme. Data was collected retrospectively from 2018-2020 for 85 patients receiving caplacizumab, including 4 children, from 22 UK hospitals. Patient characteristics and outcomes in the real-world clinical setting were compared with caplacizumab trial endpoints and historical outcomes in the pre-caplacizumab era. 84/85 patients received steroid and rituximab alongside PEX; 26% required intubation. Median time to platelet count normalisation (3 days), duration of PEX (7 days) and hospital stay (12 days) was comparable with RCT data. Median duration of PEX and time from PEX initiation to platelet count normalisation was favourable compared with historical outcomes (p<0.05). TTP recurrence occurred in 5/85 patients; all with persistent ADAMTS13 activity <5iu/dL. Of 31 adverse events in 26 patients, 17/31 (55%) were bleeding episodes and 5/31 (16%) were thrombotic events (two unrelated to caplacizumab); mortality was 6% (5/85), with no deaths attributed to caplacizumab. In 4/5 deaths caplacizumab was introduced >48 hours after PEX initiation (3-21 days). This real-world evidence represents the first and largest series of TTP patients receiving caplacizumab outside clinical trials, including paediatric patients. Representative of true clinical practice, the findings provide valuable information for clinicians treating TTP globally.

The Bruton tyrosine kinase (Btk) inhibitor ibrutinib induces platelet dysfunction and causes increased risk of bleeding. Off-target inhibition of Tec is believed to contribute to platelet dysfunction and other side effects of ibrutinib. The second-generation Btk inhibitor acalabrutinib was developed with improved specificity for Btk over Tec. We investigated platelet function in patients with non-Hodgkin lymphoma (NHL) receiving ibrutinib or acalabrutinib by aggregometry and by measuring thrombus formation on collagen under arterial shear. Both patient groups had similarly dysfunctional aggregation responses to collagen and collagen-related peptide, and comparison with mechanistic experiments in which platelets from healthy donors were treated with the Btk inhibitors suggested that both drugs inhibit platelet Btk and Tec at physiological concentrations. Only ibrutinib caused dysfunctional thrombus formation, whereas size and morphology of thrombi following acalabrutinib treatment were of normal size and morphology. We found that ibrutinib but not acalabrutinib inhibited Src family kinases, which have a critical role in platelet adhesion to collagen that is likely to underpin unstable thrombus formation observed in ibrutinib patients. We found that platelet function was enhanced by increasing levels of von Willebrand factor (VWF) and factor VIII (FVIII) ex vivo by addition of intermediate purity FVIII (Haemate P) to blood from patients, resulting in consistently larger thrombi. We conclude that acalabrutinib avoids major platelet dysfunction associated with ibrutinib therapy, and platelet function may be enhanced in patients with B-cell NHL by increasing plasma VWF and FVIII.

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We make the following recommendations for the management of suspected cases of IVIg-induced haemolysis: Stop IVIg infusion and perform tests for haemolysis. Check titres of anti-blood group antibodies in IVIg. Provide supportive management for patient with fluid and/or red blood cell transfusions if necessary. Consider quarantine of the IVIg batch if found to be high titre for anti-A/B. Report reaction to regulatory/vigilance body.

Background Platelet dysfunction, including that caused by antiplatelet agents, increases the risk of perioperative bleeding. The optimal management of patients with platelet dysfunction undergoing surgery is unclear. Objectives To assess whether desmopressin reduces perioperative allogeneic red cell transfusion and bleeding in patients with platelet dysfunction. Patients/Methods We searched for randomized controlled trials in The Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, Embase, the Transfusion Evidence Library and the ISI Web of Science to 7th July 2016. Data were pooled using mean difference (MD), relative risks or Peto odds ratios (pOR) using a random-effects model. Results Ten trials with 596 participants were identified, all in the setting of cardiac surgery. Platelet dysfunction was due to antiplatelet agents in six trials and cardiopulmonary bypass in four trials. Patients treated with desmopressin were transfused with fewer red cells (MD, -0.65 units; 95% Confidence Interval [CI], -1.16 to -0.13 units), lost less blood (MD, -253.93 mL; 95% CI, -408.01 to -99.85 mL) and had a lower risk of re-operation due to bleeding (pOR, 0.39; 95% CI, 0.18-0.84). The GRADE quality of evidence was very low to moderate, suggesting considerable uncertainty over the results Conclusions Desmopressin may be a useful agent to reduce bleeding and transfusion requirements for people with platelet dysfunction or with a history of recent antiplatelet drug administration undergoing cardiac surgery.

This review has found no evidence to support the prophylactic administration of FFP to patients without coagulopathy undergoing elective cardiac surgery. There was insufficient evidence about treatment of patients with coagulopathies or those who are undergoing emergency surgery. There were no reported adverse events attributable to FFP transfusion, although there was a significant increase in the number of patients requiring red cell transfusion who were randomised to FFP. Variability in outcome reporting between trials precluded meta-analysis for many outcomes across all trials, and there was evidence of a high risk of bias in most of the studies. Further adequately powered studies of FFP, or comparable pro-haemostatic agents, are required to assess whether larger reductions in prothrombin time translate into clinical benefits. Overall the evidence from randomised controlled trials for the safety and efficacy of prophylactic transfusion of FFP for cardiac surgery is insufficient.