and14 Manchester Royal Infirmary, Manchester, United Kingdom Key Points• In women presenting with an initial diagnosis of TTP during pregnancy, cTTP was more common than acquired TTP.• Active monitoring and management during pregnancy results in positive pregnancy outcomes.Pregnancy can precipitate thrombotic thrombocytopenic purpura (TTP). We present a prospective study of TTP cases from the United Kingdom Thrombotic Thrombocytopenic Purpura (UK TTP) Registry with clinical and laboratory data from the largest cohort of pregnancy-associated TTP and describe management through pregnancy, averting fetal loss and maternal complications. Thirty-five women presented with a first TTP episode during pregnancy: 23/47 with their first congenital TTP (cTTP) episode and 12/47 with acute acquired TTP in pregnancy. TTP presented primarily in the third trimester/ postpartum, but fetal loss was highest in the second trimester. Fetal loss occurred in 16/38 pregnancies before cTTP was diagnosed, but in none of the 15 subsequent managed pregnancies. Seventeen of 23 congenital cases had a missense mutation, C3178T, within exon 24 (R1060W). There were 8 novel mutations. In acquired TTP presentations, fetal loss occurred in 5/18 pregnancies and 2 terminations because of disease. We also present data on 12 women with a history of nonpregnancy-associated TTP: 18 subsequent pregnancies have been successfully managed, guided by ADAMTS13 levels. cTTP presents more frequently than acquired TTP during pregnancy and must be differentiated by ADAMTS13 analysis. Careful diagnosis, monitoring, and treatment in congenital and acquired TTP have assisted in excellent pregnancy outcomes. (Blood. 2014;124(2):211-219)

Key Points• Fibtem is an early and rapidly available biomarker for predicting progression of moderate to severe postpartum hemorrhage.• Fibtem was predictive of need for blood transfusion and invasive procedures, bleeds .2500 mL, duration of bleed, and time in high dependency.

No abstract

Congenital thrombotic thrombocytopenic purpura (cTTP) is an ultra-rare thrombomicroangiopathy caused by an inherited deficiency of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13). There are limited data on genotype-phenotype correlation; there is no consensus on treatment. We reviewed the largest cohort of cTTP cases, diagnosed in the United Kingdom, over the past 15 years. Seventy-three cases of cTTP were diagnosed, confirmed by genetic analysis. Ninety-three percent were alive at the time of review. Thirty-six percent had homozygous mutations; 64% had compound heterozygous mutations. Two presentation peaks were seen: childhood (median diagnosis age, 3.5 years) and adulthood, typically related to pregnancy (median diagnosis age, 31 years). Genetic mutations differed by age of onset with prespacer mutations more likely to be associated with childhood onset (P = .0011). Sixty-nine percent of adult presentations were associated with pregnancy. Fresh-frozen plasma (FFP) and intermediate purity factor VIII concentrate were used as treatment. Eighty-eight percent of patients with normal blood counts, but with headaches, lethargy, or abdominal pain, reported symptom resolution with prophylactic therapy. The most common currently used regimen of 3-weekly FFP proved insufficient for 70% of patients and weekly or fortnightly infusions were required. Stroke incidence was significantly reduced in patients receiving prophylactic therapy (2% vs 17%; P = .04). Long-term, there is a risk of end-organ damage, seen in 75% of patients with late diagnosis of cTTP. In conclusion, prespacer mutations are associated with earlier development of cTTP symptoms. Prophylactic ADAMTS13 replacement decreases the risk of end-organ damage such as ischemic stroke and resolved previously unrecognized symptoms in patients with nonovert disease.

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.

This guideline was compiled according to the British Society for Haematology (BSH) process at https://b-s-h.org.uk/med ia/16732/bsh-guidance-development-process-dec-5-18.pdf. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) nomenclature was used to evaluate levels of evidence and to assess the strength of recommendations. The GRADE criteria can be found at http:// www.gradeworkinggroup.org. The references to support the recommendations are listed in the preceding discussion. Literature review The information contained in this review was gathered from several sources. These included references from a search of MEDLINE, EMBASE and the Cochrane databases to identify studies and reviews relevant to prophylaxis in patients with haemophilia, abstracts from international meetings and references known to the authors (Appendix S1). Review of the manuscript The writing group produced the draft guideline, which was subsequently revised by consensus. Review of the manuscript was performed by the BSH Guidelines Committee Haemostasis and Thrombosis Taskforce, the BSH Guidelines Committee and the Haemostasis and Thrombosis sounding board of the BSH. It was also on the members section of the BSH website for comment. It has also been reviewed by members of the United Kingdom Haemophilia Centre Doctors' Organisation (UKHCDO) Advisory Board, Haemophilia Nurses Association (HNA), Haemophilia Chartered Physiotherapists Association (HCPA); these organisations do not necessarily approve or endorse the contents.

No abstract

This is the first study to report on the investigation and treatment of UBD. Future studies are needed to further our understanding of the bleeding phenotype and identify any underlying causes.