A British Society for Haematology Guideline: Diagnosis and management of thrombotic thrombocytopenic purpura and thrombotic microangiopathies.

The objective of this guideline is to provide healthcare professionals with clear, up-to-date and practical guidance on the management of thrombotic thrombocytopenic purpura (TTP) and related thrombotic microangiopathies (TMAs), including complement-mediated haemolytic uraemic syndrome (CM HUS); these are defined by thrombocytopenia, microangiopathic haemolytic anaemia (MAHA) and small vessel thrombosis. Within England, all TTP cases should be managed within designated regional centres as per NHSE commissioning for highly specialised services.

Adjudicated myocarditis and multisystem illness trajectory in healthcare workers post-COVID-19.

BACKGROUND: We investigated the associations of healthcare worker status with multisystem illness trajectory in hospitalised post-COVID-19 individuals. METHODS AND RESULTS: One hundred and sixty-eight patients were evaluated 28-60 days after the last episode of hospital care. Thirty-six (21%) were healthcare workers. Compared with non-healthcare workers, healthcare workers were of similar age (51.3 (8.7) years vs 55.0 (12.4) years; p=0.09) more often women (26 (72%) vs 48 (38%); p<0.01) and had lower 10-year cardiovascular risk (%) (8.1 (7.9) vs 15.0 (11.5); p<0.01) and Coronavirus Clinical Characterisation Consortium in-hospital mortality risk (7.3 (10.2) vs 12.7 (9.8); p<0.01). Healthcare worker status associated with less acute inflammation (peak C reactive protein 48 mg/L (IQR: 14-165) vs 112 mg/L (52-181)), milder illness reflected by WHO clinical severity score distribution (p=0.04) and shorter duration of admission (4 days (IQR: 2-6) vs 6 days (3-12)).In adjusted multivariate logistic regression analysis, healthcare worker status associated with a binary classification (probable/very likely vs not present/unlikely) of adjudicated myocarditis (OR: 2.99; 95% CI (1.01 to 8.89) by 28-60 days postdischarge).After a mean (SD, range) duration of follow-up after hospital discharge of 450 (88) days (range 290, 627 days), fewer healthcare workers died or were rehospitalised (1 (3%) vs 22 (17%); p=0.038) and secondary care referrals for post-COVID-19 syndrome were common (42%) and similar to non-healthcare workers (38%; p=0.934). CONCLUSION: Healthcare worker status was independently associated with the likelihood of adjudicated myocarditis, despite better antecedent health. Two in five healthcare workers had a secondary care referral for post-COVID-19 syndrome. TRIAL REGISTRATION NUMBER: NCT04403607.

Changes in laboratory markers of thrombotic risk early in the first trimester of pregnancy may be linked to an increase in estradiol and progesterone.

BACKGROUND: Pregnant women are at increased risk of venous thrombosis compared to non-pregnant women. Epidemiological and laboratory data suggest that hypercoagulability begins in the first trimester but it is unknown exactly how early in pregnancy this develops. The mechanisms that result in a prothrombotic state may involve oestrogens and progestogens. METHODS: Plasma samples were taken prior to conception and five times in early pregnancy, up to Day 59 gestation, from 22 women undergoing natural cycle in vitro fertilization, who subsequently gave birth at term following a normal pregnancy. Thrombin generation, free Protein S, Ddimer, Fibrinogen, factor VIII, estradiol and progesterone were measured. To counter inter-individual variability, the change in laboratory measurements between the pre-pregnant and pregnant state were measured over time. RESULTS: Peak thrombin, Endogenous Thrombin Potential, Velocity Index and fibrinogen significantly increased, and free Protein S significantly decreased, from pre-pregnancy levels, by 32 days gestation. Ddimer and VIII significantly increased from pre-pregnancy levels by 59 days gestation. Estradiol significantly increased by Day 32 gestation with a non-significant increase of 67% by Day 24 gestation. Progesterone significantly increased by Day 32 gestation. Almost all laboratory markers of thrombosis correlated significantly with estradiol and progesterone. CONCLUSION: Our work is the first to demonstrate that the prothrombotic state develops very early in the first trimester. Laboratory markers of hypercoagulability correlate significantly with estradiol and progesterone suggesting these are linked to the prothrombotic state of pregnancy. Clinicians should consider commencing thromboprophylaxis early in the first trimester in women at high thrombotic risk.

A British Society for haematology guideline: diagnosis and management of thrombotic thrombocytopenic purpura and thrombotic microangiopathies

The objective of this guideline is to provide healthcare professionals with clear, up-to-date and practical guidance on the management of thrombotic thrombocytopenic purpura (TTP) and related thrombotic microangiopathies (TMAs), including complement-mediated haemolytic uraemic syndrome (CM HUS); these are defined by thrombocytopenia, microangiopathic haemolytic anaemia (MAHA) and small vessel thrombosis. Within England, all TTP cases should be managed within designated regional centres as per NHSE commissioning for highly specialised services.

Normal pregnancy is associated with an increase in thrombin generation from the very early stages of the first trimester.

BACKGROUND: Pregnancy is a hypercoagulable state associated with an increased risk of venous thrombosis, which begins during the first trimester, but the exact time of onset is unknown. Thrombin generation, a laboratory marker of thrombosis risk, increases during normal pregnancy but it is unclear exactly how early this increase occurs. METHODS: We assessed thrombin generation by Calibrated Automated Thrombography in women undergoing natural cycle in vitro fertilization, who subsequently gave birth at term following a normal pregnancy (n=22). Blood samples were taken just prior to conception and repeated five times during very early pregnancy, up to Day 59 estimated gestation. RESULTS: Mean Endogenous Thrombin Potential (ETP), peak thrombin generation and Velocity Index (VI) increased significantly from pre-pregnancy to Day 43 gestation (p=0.024-0.0004). This change persisted to Day 59 gestation. The mean of the percentage change from baseline, accounting for inter-individual variation, in ETP, peak thrombin and VI increased significantly from pre-pregnancy to Day 32 gestation (p=0.0351-<0.0001) with the mean increase from baseline persisting to Day 59 gestation. CONCLUSION: Thrombin generation increases significantly during the very early stages of normal pregnancy when compared to the pre-pregnancy state. The increased risk of venous thrombosis therefore likely begins very early in a woman's pregnancy, suggesting that women considered clinically to be at high thrombotic risk should start thromboprophylaxis as early as possible after a positive pregnancy test.

[The gynaecological work by GPs in Brittany]. / L'activité gynécologique des médecins généralistes en Bretagne.

The aim of this study is to evaluate the gynaecological work done by general practitioners (GPs) in Brittany and the clarify the role that they play in screening for female cancers. Gynaecology represents approximately 10% of the total activity reported by the respondents; however, wide variations have also been noted. This raises important questions on issues such as the competence of these practitioners in this area and equity in access to care and screening, which could potential lead to problems. A large majority of the participating GPs (87%) identified prevention and screening as their primary specific roles to carry out in the care of their female patients. The main reasons for seeking gynaecological consultation are contraception and hormone replacement therapy, and these are the two themes for which GPs request further medical training and continuing education possibilities. Gynaecological work done within the scope of general practice can be hindered by various factors or obstacles: some stem from the doctors themselves (inadequate skills, little interest in this speciality), or rather may be linked to their working conditions (dealing with several reasons for a patient seeking consultation at the same time), while others are a result of how women (or even the doctors themselves) view the tests (reluctance or lack of confidence in the doctors' ability to carry them out properly). In order for GPs to be more involved and implicated in this field, there would need to be the introduction of an efficient and adapted training as well as compatible and effective continuing education programmes suitable to respond to the needs and requirements of the GPs practicing in this area.

Establishing a reference range for thrombin generation using a standard plasma significantly improves assay precision.

BACKGROUND: Thrombin generation is a global coagulation assay which appears to be an effective method for assessing the potential for an individual's plasma to coagulate. However for this assay to become accepted in routine clinical practice it requires standardization. OBJECTIVES: To establish a reference range for the NIBSC reference plasma (TGT-RP) which can then become an internal quality control (IQC) for thrombin generation assays. PATIENTS/METHODS: Thrombin generation was measured in TGT-RP in 153 independent experiments using 4 assay conditions; 1 pM tissue factor (TF) or 5 pM TF +/- thrombomodulin (TM). A target value +/- 2 SD was calculated to provide an acceptance range under the 4 conditions. A plasma sample from a healthy volunteer was subsequently tested in 11 separate experiments using the TGT-RP for (i) normalisation and (ii) exclusion of experimental results when the TGT-RP results did not fall within the established acceptance range. RESULTS: An acceptance range was established for TGT-RP for the 4 assay conditions. Normalisation of all results from a healthy volunteer reduced inter-assay variability significantly (ETP: p=0.0003; Peak: p=0.001). Exclusion of results from the volunteer when concurrently run TGT-RP results fell outside the acceptance range reduced inter-assay variability significantly when reporting raw data (ETP: p=0.001; Peak: p=0.004). However normalisation of this data had no beneficial effect (ETP: p=0.126; Peak: p=0.232). CONCLUSIONS: Our work represents further progress in the standardization of thrombin generation techniques with the establishment of an IQC reference range. Using an IQC reduces inter-assay variability, whilst allowing reporting of raw data and ensures production of accurate and reproducible data.

The use of an exclusion-based risk-assessment model for venous thrombosis improves uptake of appropriate thromboprophylaxis in hospitalized medical patients.

BACKGROUND: Venous thromboembolism is a common condition in hospitalized medical patients. Numerous studies have demonstrated that low molecular weight heparin significantly reduces this risk but, despite this, the use of thromboprophylaxis remains poor. AIM: To evaluate the use of an exclusion based risk-assessment model (RAM) for venous thrombosis in improving the uptake of appropriate thromboprophylaxis in hospitalized medical patients. DESIGN: A survey with a subsequent audit cycle of three separate audits over 36 months. METHODS: 497 hospitalized patients with acute medical conditions on general medical wards were audited at a secondary care centre in London, UK. The survey and subsequent audits were performed by reviewing the notes and medication charts of medical patients, prior to the launch of the RAM and at 12, 28 and 36 months following its introduction. RESULTS: Prior to launching the RAM, 49% of hospitalized medical patients received appropriate thromboprophylaxis. This did not change 12 months after the RAM was introduced but increased significantly to 71% following formal education of the health care professionals involved in thromboprophylaxis prescription. This improvement was maintained as demonstrated by a subsequent audit 8 months later (75.9%). CONCLUSION: The introduction of a simple exclusion-based RAM for venous thrombosis in medical patients significantly improved delivery of thromboprophylaxis. The successful uptake of the RAM appears to have been dependent on direct education of those health carers involved in its use. A similar exclusion-based model used nationally could have a significant impact on the burden of VTE currently experienced in the UK.

The effect of estrone on thrombin generation may explain the different thrombotic risk between oral and transdermal hormone replacement therapy.

BACKGROUND: The metabolism of estrogen contained within hormone replacement therapy (HRT) is influenced by the route of administration, and this may affect the risk of venous thromboembolism. Thrombin generation, a global coagulation assay, is a marker of hypercoagulability and is of potential use in determining the thrombotic risk associated with particular HRT administration routes. OBJECTIVES: To determine whether any effect of oral and transdermal HRT on thrombin generation is related to the plasma estrogen profile. METHODS: We investigated the effects of oral, transdermal and no HRT (controls) in 52, 39 and 52 postmenopausal women, respectively, on thrombin generation, standard markers of thrombophilia, estradiol level and estrone level. RESULTS: All parameters of thrombin generation were altered in women using oral HRT as compared with controls (P<0.001 for all comparisons). No such differences were found in women using transdermal HRT. Estrone levels correlated with peak thrombin generation (R=0.451, P<0.001) in women using oral HRT, but there was no correlation in women using the transdermal route. CONCLUSIONS: Thrombin generation is significantly increased in women who use HRT administered by the oral route. This is probably mediated by the hepatic first-pass metabolism of estrone, the main metabolite of oral estradiol, which is avoided by the transdermal route. The effect of estrone on thrombin generation may provide the explanation for the higher thrombotic risk seen in women using oral rather than transdermal HRT.

Alteration of maternal Hoxa10 expression by in vivo gene transfection affects implantation.

Mice with a targeted mutation of the Hoxa10 gene demonstrate uterine factor infertility. It is unclear if the defect in the uterine environment arises due to the absence of Hoxa10 expression during embryonic development or in the adult. We have recently demonstrated that HOXA10 expression in human endometrium rises dramatically at the time of implantation, suggesting maternal expression of Hoxa10/HOXA10 may be essential to the process. To assess the importance of maternal Hoxa 10 expression, the uteri of day 2 pregnant mice were injected with a DNA/liposome complex containing constructs designed to alter maternal Hoxa10 expression before implantation. Transfection with a Hoxa10 antisense oligodeoxyribonucleotide significantly decreased the number of implantation sites. Transfection with a plasmid which constitutively expresses Hoxa10 optimized survival of implanted embryos resulting in increased litter size. These results demonstrate that maternal Hoxa10 expression is essential for implantation and is the first report of the maternal alteration of a gene known to affect implantation specifically. We also demonstrate that DNA/liposome complexes containing the same Hoxa10 constructs that alter fertility in mice, can affect Hoxa10 expression in a human endometrial cell line. Alteration of human endometrial HOXA10 via liposome-mediated gene transfection is a potential contraceptive agent or fertility treatment.

Maternal Hoxa10 is required for pinopod formation in the development of mouse uterine receptivity to embryo implantation.

Hoxa10 is a homeobox gene that is expressed both during the embryogenesis of the genitourinary tract and in the adult reproductive tract. Maternal Hoxa10 expression is necessary for endometrial receptivity to blastocyst implantation. The mechanism by which Hoxa10 induces endometrial development to a state of receptivity is unknown as HOXA10-deficient endometrium appears histologically normal. We altered the expression of Hoxa10 in the uterus of cycling adult female mice and examined the uterus at the time of implantation by transmission electron microscopy for alterations in epithelial morphology. Pinopods are projections on the surface of the uterine endometrial epithelial cells that develop transiently at the time of endometrial receptivity. Blocking Hoxa10 expression by transfection of Hoxa10 antisense into the cycling mouse uterus before implantation dramatically decreased pinopod number. Constitutively expressing Hoxa10 in the uterus just before the normal time of pinopod formation resulted in increased pinopod number. Therefore, Hoxa10 is necessary for pinopod development. Hox genes have been implicated in both the regulation of cellular proliferation and the determination of developmental fate. Hoxa10 exemplifies this dual role in the uterus by regulating both endometrial stromal cell proliferation and epithelial cell morphogenesis. Taken together, these results demonstrate that maternal Hoxa10 has an essential role in pinopod development and this function of Hoxa10 likely contributes to endometrial receptivity for the purpose of blastocyst implantation.

Comparison of the effects of zolpidem and triazolam on memory functions, psychomotor performances, and postural sway in healthy subjects.

Zolpidem is a rapid-onset, short-duration imidazopyridine hypnotic drug and is specific agonist of the omega-1 (BZD1) receptors. Its hypnotic characteristics resemble those of triazolam. The aims of this study were to assess the effects of zolpidem on memory (the main objective), psychomotor performances, and postural sway (secondary objectives) in 18 healthy subjects and to compare them with those of triazolam and placebo. Short- and long-term memory (paired words associate and pictures test), psychomotor performances (critical flicker fusion frequency, choice reaction time, digit symbol substitution test), and postural sway were evaluated before and 1.5, 4, 6, and 8 h after the administration of a single dose of zolpidem (10 mg), triazolam (0.25 mg), and placebo. For each assessment, the maximal effect for both hypnotic drugs occurred 1.5 hour after intake. Both drugs decreased psychomotor performance, impaired memory, and increased postural sway. The effects of both hypnotic agents were short lasting, and no alterations were found 6 and 8 hours, respectively, after drug intake. No clinically relevant differences were found between zolpidem and triazolam for memory, psychomotor performance, postural sway, or adverse effects. It may be concluded that zolpidem, like triazolam, impairs short- and long-term memory, psychomotor performances, and postural sway and that these effects are of short duration.

HOX gene expression is altered in the endometrium of women with endometriosis.

HOXA10 and HOXA11 are homeobox genes that function as transcription factors essential to embryonic development. We have recently described a role for each of these two genes in regulating endometrial development in the adult during the course of a menstrual cycle. Both Hoxa10 and Hoxa11 are essential for implantation in the mouse and appear to play a similar role in women. To investigate the role of HOX genes in the endometrium of women with endometriosis, quantitative Northern blot analysis was performed on the endometrium of 40 normal cycling controls and 40 patients with documented endometriosis. Patients with endometriosis failed to show the expected mid-luteal rise in HOX gene expression as demonstrated in the controls. Aberrant HOX gene expression suggests that altered development of the endometrium at the molecular level may contribute to the aetiology of infertility in patients with endometriosis.