Use of the Delphi method to facilitate antithrombotics prescription during pregnancy

Assessment-based management of placenta-mediated pregnancy complications: Pragmatism until a precision medicine approach evolves

The management of pregnant women with thrombophilia and a history of gestational vascular complications remains debatable. Treatment of the latter is often based on clinical outcome rather than disease mechanism. While the use of venous thromboembolism prophylaxis in pregnancy is recommended for those at increased risk, the ability of anticoagulant and/or antiplatelet agents to lower the risk of placenta-mediated complications in this clinical setting remains controversial. The available guidelines are inconsistent in some situations, which reflects the limited evidence base. This review critically discusses risk assessment models (RAMs) and management strategies of women with thrombophilia and pregnancy complications, using clinical vignettes. RAMs, taking into account obstetric and thrombotic history as well as thrombophilia status, could drive a precision medicine approach, based on disease mechanism, and guide individual therapeutic interventions in high-risk clinical settings.

Venous Thromboembolism Associated with Assisted Reproductive Technology: A Systematic Review and Meta-analysis

BACKGROUND

 Hormonal exposure leads to an increased risk of venous thromboembolism (VTE) but the risk of VTE associated with assisted reproductive technology (ART) is not clearly determined.

METHODS

 We searched in PubMed, EMBASE, Web of Science, and the Cochrane Library databases and identified all relevant articles published up to February 1, 2021. The primary objective was to determine the frequency of VTE associated with ART. Secondary objectives were to determine (1) the risk of VTE associated with ART as compared to pregnancy without ART; (2) the risk of VTE associated with ovarian hyperstimulation syndrome (OHSS); and (3) to determine potential risk factors of VTE related to ART.

RESULTS

 Fourteen studies were included. The overall frequency of VTE associated with ART was 0.23% (95% confidence interval [CI]: 0.07-0.46). Women undergoing ART had a two- to threefold increased risk of VTE as compared to spontaneous pregnancy (relative risk [RR]: 2.66; 95% CI: 1.60-4.43). The overall frequency of VTE specifically related to OHSS was <0.001%. The risk of VTE after ART complicated by OHSS, as compared to ART without OHSS, was higher but not statistically significant (RR: 14.83; 95% CI: 0.86-255.62). Risk factors of VTE associated with ART were in vitro fertilization procedure (RR, odds ratio [OR], and hazard ratio varying from 1.77, 95% CI: 1.41-2.23 to 4.99, 95% CI: 1.24-20.05), hyperhomocysteinemia (OR: 15.2; 95% CI: 2.0-115.0), polycystic ovarian syndrome (PCOS) (RR: 4.8; 95% CI: 1.7-13.4), successful ART leading to pregnancy (OR: 13.94; 95% CI: 1.41-137.45).

CONCLUSION

 Further large prospective studies on risk factors of VTE in women undergoing ART are needed in order to optimize thromboprophylaxis in this context.

Microsurgical Breast Reconstruction in Patients with Disorders of Hemostasis: Perioperative Risks and Management

BACKGROUND

Surgical and technological advances have resulted in the widespread adoption of microsurgical breast reconstruction. Many comorbidities that potentially might impair vasculature and wound healing are no longer considered contraindications for these procedures. However, some uncertainty still prevails regarding the perioperative management of patients with disorders of hemostasis.

METHODS

The authors combined a literature review with a retrospective chart review of patients with disorders of hemostasis who had undergone microsurgical breast reconstruction at the senior author's (J.F.) center between 2015 to 2020. Several disorders associated with thrombotic and/or hemorrhagic complications were identified, and a standardized risk assessment and management strategy was developed in cooperation with a hematologist.

RESULTS

Overall, 10 studies were identified comprising 29 patients who had a defined disorder of hemostasis and underwent microsurgical breast reconstruction. Seventeen microsurgical breast reconstructions were performed on 11 patients at the senior author's (J.F.) center. High factor VIII levels, heterozygous factor V Leiden, and heterozygous prothrombin mutation G20210A were the most common genetic or mixed genetic/acquired thrombophilic conditions. As expected, hereditary antithrombin, protein C, or protein S deficiencies were rare. Among hemorrhagic disorders, thrombocytopenia, platelet dysfunction, and von Willebrand disease or low von Willebrand factor levels were those factors most frequently associated with increased perioperative bleeding.

CONCLUSIONS

Patients should be screened for elevated risk of thrombosis or bleeding before undergoing microsurgical breast reconstruction, and positive screening should prompt a complete hematologic evaluation. Interdisciplinary management of these disorders with a hematologist is essential to minimize risks and to obtain optimal reconstructive results.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, IV.

The Risk of Thrombosis Around Pregnancy: Where Do We Stand?

Pregnancy and puerperium increase the relative risk of venous thromboembolism (VTE) and the absolute risk remains low, around 1 per 1,000, with induced mortality of around 1 per 100,000. Analysis of large databases has helped specify the modes of presentation and risk factors (RF) whose impact is greater after than before childbirth, since VTE during pregnancy and post-partum obey different RFs. The evolution of the population concerned (mostly women over 35, obese, of multi-ethnicity undergoing medically assisted reproduction) affects the frequency of these RFs. Pulmonary embolism (PE) is over-represented after childbirth, but 30% of PE in pregnancy occurs without any RFs. Recommendations for prevention, mainly from expert groups, are heterogeneous and often discordant. Low molecular weight heparins (LMWH) are the mainstay of pharmacological thromboprophylaxis, in a field where randomized controlled studies are definitely lacking. VTE risk assessment in pregnancy must be systematic and repetitive. Risk assessment methods and scores are beginning to emerge to guide thromboprophylaxis and should be used more systematically. In the future, analyzing observational data from huge, nationwide registries and prospective cluster clinical trials may bring to light clinically relevant outcomes likely to feed comprehensive guidelines.

Venous Thromboembolism Risk Score and Pregnancy

Venous thromboembolism (VTE) is a major contributor to maternal morbidity and mortality worldwide. Pregnancy is associated with the development of a baseline hypercoagulable state. The two strongest risk factors for pregnancy-associated VTE are previous VTE and/or high risk thrombophilia. The others risk factors for VTE during pregnancy are well known such as maternal, pregnancy and delivery characteristics. Considering the variation in recommendation in guidelines and low-quality evidence on the prevention, diagnosis and treatment, practice differs between countries and clinical institutions. Some authors developed risk scores, enabling individualized estimation of thrombotic risk during pregnancy, and permitting implementation of a risk-adapted strategy for thromboprophylaxis during pregnancy and postpartum. This review describes the existing VTE risk scores during the antenatal and postnatal period. The important message beyond the score used is that all women should undergo VTE risk factor assessment. The use of a Computerized Clinical Decision Support System for VTE risk assessment should be explored in obstetrics.

Appraising screening, making risk in/visible. The medical debate over Non-Rare Thrombophilia (NRT) testing before prescribing the pill

Non-rare thrombophilia (NRT) are hereditary predispositions to thromboembolism, the most severe side effect of combined hormonal contraception. In the mid-1990s, the identification of NRT stirred up a controversy over the possibility of investigating these genetic variants in women wishing to use contraception. Through a review of literature, this article reconstructs the debate over whether and how this genetic test should be prescribed as a way to reconfigure the risk visibility on pharmacological contraception. The main arguments identified concern the epidemiological, social, economic and clinical aspects of the test. In a context where the overall thrombotic risk for hormonal contraception is largely invisible, the genetic tests turn to embody the thrombotic risk itself. Those who opt for selective screening argue that a better estimation of risk implies a test prescription embed in a global medical assessment of women's individual risk. To advocates of universal or 'extended' screening, the tests are valuable tools to inform women on the thrombotic risk and, as such, appraised as a moral/legal obligation, whatever their predictive power. Risk visibility thus appears as an insightful concept to analyse a complex setting associating clinical, political, social and cultural considerations that touches upon medical power, women's responsibility and drug safety.

Current opinion and emerging trends on the treatment, diagnosis, and prevention of pregnancy-associated venous thromboembolic disease: a review

Pregnancy associated venous thromboembolism (PA-VTE) is a leading cause of maternal morbidity and mortality worldwide. Despite the availability of international guidance on the prevention, diagnosis and treatment, practice differs between countries and clinical institutions. The evidence base in this area is limited due to the vulnerable population who are affected, with the majority of guidelines deriving their recommendations from experience in surgical and medical venous thromboembolic disease. This review includes best evidence in PA-VTE management, highlighting specific literature which supports current diagnosis, prevention, and treatment strategies. Additionally, we hope to demonstrate emerging trends in the field through discussion of ongoing trials designed to progress towards evidence-based practice in the context of PA-VTE.

Safety Assessment of Casting Workshop by Cloud Model and Cause and Effect-LOPA to Protect Employee Health

Safety assessment of a casting workshop will provide a clearer understanding of the important safety level required for a foundry. The main purpose of this study was to construct a composite safety assessment method to protect employee health using the cloud model and cause and effect–Layer of Protection Analysis (LOPA). In this study, the weights of evaluation indicators were determined using the subjective analytic hierarchy process and objective entropy weight method respectively. Then, to obtain the preference coefficient of the integrated weight more precisely, a new algorithm was proposed based on the least square method. Next, the safety level of the casting workshop was presented based on the qualitative and quantitative analysis of the cloud model, which realized the uncertainty conversion between qualitative concepts and their corresponding quantitative values, as well as taking the fuzziness and randomness into account; the validity of cloud model evaluation was validated by grey relational analysis. In addition, cause and effect was used to proactively identify factors that may lead to accidents. LOPA was used to correlate corresponding safety measures to the identified risk factors. 6 causes and 19 sub-causes that may contribute to accidents were identified, and 18 potential remedies, or independent protection layers (IPLs), were described as ways to protect employee health in foundry operations. A mechanical manufacturing business in Hunan, China was considered as a case study to demonstrate the applicability and benefits of the proposed safety assessment approach.

Prophylaxis and Therapy of Venous Thrombotic Events (VTE) in Pregnancy and the Postpartum Period

Venous thromboembolisms and pulmonary embolisms are one of the main causes of morbidity and mortality in pregnancy. The increased risk of thrombotic events caused by the physiological changes during pregnancy alone does not justify any medical antithrombotic prophylaxis. However, if there are also other risk factors such as a history of thromboses, hormonal stimulation as part of fertility treatment, thrombophilia, increased age of the pregnant woman, severe obesity or predisposing concomitant illnesses, the risk of thrombosis should be re-evaluated - if possible by a coagulation specialist - and drug prophylaxis should be initiated, where applicable. Low-molecular-weight heparins (LMWH) are the standard medication for the prophylaxis and treatment of thrombotic events in pregnancy and the postpartum period. Medical thrombosis prophylaxis started during pregnancy is generally continued for about six weeks following delivery due to the risk of thrombosis which peaks during the postpartum period. The same applies to therapeutic anticoagulation after the occurrence of a thrombotic event in pregnancy; here, a minimum duration of the therapy of three months should also be adhered to. During breastfeeding, LMWH or the oral anticoagulant warfarin can be considered; neither active substance passes into breast milk.

Safety assessment of petrochemical enterprise using the cloud model, PHA-LOPA and the bow-tie model

Safe production is the foundation of the normal operations of petrochemical enterprises, and it helps maintain social stability. The main purpose of this study is to prevent petrochemical enterprise accidents by proposing a composite safety assessment approach based on the cloud model, preliminary hazard analysis-layer of protection analysis (PHA-LOPA) and the bow-tie model. First, the petrochemical enterprise and its relevant indicators were evaluated based on the cloud model. Second, the quantitative effect of the uncertainty transformation on the evaluation result of the cloud model was further analysed. This mainly includes the error analysis of the numerical characteristics under the conditions of few samples and small values. Third, the critical indicators such as shock and noise can be weakened and prevented by corresponding safety measures based on PHA-LOPA and the bow-tie model. After adopting two independent protection layers, the risk levels of shock and noise decrease from 3 to 2. Then, shock and noise were analysed in depth with the bow-tie model, and the causes and consequences were identified. Moreover, corresponding safety measures were taken to prevent accidents. The case study validated the validity and feasibility of the composite safety assessment approach proposed here.

Mine safety assessment using gray relational analysis and bow tie model

Mine safety assessment is a precondition for ensuring orderly and safety in production. The main purpose of this study was to prevent mine accidents more effectively by proposing a composite risk analysis model. First, the weights of the assessment indicators were determined by the revised integrated weight method, in which the objective weights were determined by a variation coefficient method and the subjective weights determined by the Delphi method. A new formula was then adopted to calculate the integrated weights based on the subjective and objective weights. Second, after the assessment indicator weights were determined, gray relational analysis was used to evaluate the safety of mine enterprises. Mine enterprise safety was ranked according to the gray relational degree, and weak links of mine safety practices identified based on gray relational analysis. Third, to validate the revised integrated weight method adopted in the process of gray relational analysis, the fuzzy evaluation method was used to the safety assessment of mine enterprises. Fourth, for first time, bow tie model was adopted to identify the causes and consequences of weak links and allow corresponding safety measures to be taken to guarantee the mine's safe production. A case study of mine safety assessment was presented to demonstrate the effectiveness and rationality of the proposed composite risk analysis model, which can be applied to other related industries for safety evaluation.

Personalized thromboprophylaxis using a risk score for the management of pregnancies with high risk of thrombosis: a prospective clinical study

Essentials Pregnancy is a risk factor for thrombosis. Management of thrombosis risk in pregnancy remains a challenge. Prophylaxis needs to be personalized. Our score may be a helpful tool for the management of pregnancies at high risk of thrombosis.

SUMMARY

Background Patients with thrombophilia and/or a history of venous thromboembolism (VTE) are at risk of thrombosis during pregnancy. A risk score for pregnancies with an increased risk of VTE was previously described by our group (Lyon VTE score). Objectives The aim of this prospective study was to assess the efficacy and safety of our score-based prophylaxis strategy in 542 pregnancies managed between 2005 and 2015 in Lyon University Hospitals. Patients/Methods Of 445 patients included in the study, 36 had several pregnancies during the study period. Among these 445 patients, 279 had a personal history of VTE (62.7%), 299 patients (67.2%) had a thrombophilia marker, and 131 (29.4%) thrombophilic women had a personal history of VTE. During pregnancy, patients were assigned to one of three prophylaxis strategies according to the risk scoring system. Results In the antepartum period, low molecular weight heparin (LMWH) prophylaxis was prescribed to 64.5% of patients at high risk of VTE. Among them, 34.4% were treated in the third trimester only, and 30.1% were treated throughout pregnancy. During the postpartum period, all patients received LMWH for at least 6 weeks. Two antepartum-related VTEs (0.37%; one with a score of < 3 and the other with a score of > 6) and four postpartum-related VTEs (0.73%; three with scores of 3-5 and one with a score of > 6) occurred. No case of pulmonary embolism was observed during the study period. The rate of bleeding was 0.37%. No serious bleeding requiring transfusions or surgery occurred during the study period. Conclusion The use of a risk score may provide a rational decision process to implement safe and effective antepartum thromboprophylaxis in pregnant women at high risk of VTE.

[Venous thromboembolism and pregnancy]

Venous thromboembolism (VTE) is a major cause of maternal morbidity and mortality during or early after pregnancy. Prior VTE or family history of VTE, clinical or biological risk factors increased the risk of pregnancy-related VTE. Defining the risk of VTE before or at the beginning of pregnancy is necessary to propose the best prevention. However, the management is not standardized between physicians, centres and countries. Current guidelines for prophylaxis and treatment of VTE are discussed in this review.

[Antithrombotic therapy and pregnancy]

The incidence of venous thromboembolism (VTE) during pregnancy is about one event per 1000 pregnancies and placenta-mediated pregnancy complications (PC) occurred in 15%. Knowing the biological combined with clinical risk factors would help to prevent problems during the pregnancy. Several antithrombotic therapies exist, including very recent ones but LMWH and aspirin are still molecules of choice. The women should be assessed for VTE and PC risk in order to improve the outcome.