D-dimer to rule out venous thromboembolism during pregnancy: A systematic review and meta-analysis

Diagnostic value of D-dimer to fibrinogen ratio for pulmonary embolism in postpartum women

BACKGROUND

Pulmonary embolism is a common disease associated with high mortality and morbidity. Diagnosing pulmonary embolism is challenging due to diverse clinical presentations and the lack of specific biomarkers. The study aimed to investigate the diagnostic value on pulmonary embolism for postpartum women by D-dimer to fibrinogen ratio, and it combined with neutrophil-to-lymphocyte ratio or platelet-to-lymphocyte ratio.

METHODS

A total of 537 women with suspected pulmonary embolism were selected as the research subjects from the Shanghai First Maternity and Infant Hospital between 1 January 2019 and 31 October 2022. The D-dimer to fibrinogen ratio and it combined with neutrophil-to-lymphocyte ratio or platelet-to-lymphocyte ratio were applied to evaluate the clinical probability of pulmonary embolism, and the positive predictive value of both scores were calculated using computed tomography pulmonary arteriography as a gold standard. The diagnostic value of D-dimer to fibrinogen ratio, combined with neutrophil-to-lymphocyte ratio or platelet-to-lymphocyte ratio was evaluated by the area under the curve, sensitivity, specificity, and other indicators in the receiver operator characteristic curve.

RESULTS

Among the 502 women included for analysis, 194 (38.65%) were definitely diagnosed as pulmonary embolism. The positive predictive values of D-dimer to fibrinogen ratio and it combined with platelet-to-lymphocyte ratio or neutrophil-to-lymphocyte ratio were 70.1%, 50.5%, and 56.5%, respectively in the postpartum women, the area under the curve for the D-dimer to fibrinogen ratio and it combined with platelet-to-lymphocyte ratio or neutrophil-to-lymphocyte ratio were 0.606 (95%CI: 0.562-0.650), 0.624 (95%CI: 0.575-0.673), and 0.639 (95%CI: 0.592-0.686), respectively. The negative predictive values of D-dimer to fibrinogen ratio, it combined with platelet-to-lymphocyte ratio or neutrophil-to-lymphocyte ratio were 50.5%, 70.1%, and 69.8%, respectively.

CONCLUSION

The diagnostic value of the D-dimer to fibrinogen ratio was higher than the D-dimer for the postpartum women with suspected pulmonary embolism. The combination of either the neutrophil-to-lymphocyte ratio or the platelet-to-lymphocyte ratio with D-dimer to fibrinogen ratio is an appropriate strategy to rule out pulmonary embolism.

Venous thromboembolism in pregnant obese Individuals

Venous thrombosis and thromboembolism (VTE) remain the leading cause of direct maternal deaths, occurring within 42 days of the end of pregnancy in the UK. Pregnancy is associated with an overall 10-fold higher incidence of VTE than in the non-pregnant state and has been reported to reach up to 30-fold higher in the puerperium. This increased risk is further exacerbated by maternal obesity in a relationship that appears to be proportional with increasing Body Mass Index (BMI). Maternal obesity is the most common health problem in women of reproductive age with clinically significant health risks to women during pregnancy and after delivery. It is associated with poor perinatal and maternal outcomes, The incidence of maternal obesity has increased significantly worldwide over the last few decades and increasingly, pregnancy is being complicated by extreme or morbid obesity. In this review we discuss the challenges associated with the diagnosis and management of VTE in obese pregnant women and provide a review of the available current evidence.

Diagnostic strategies in postpartum individuals with suspected venous thromboembolism: A scoping review

BACKGROUND

The risk of venous thromboembolism (VTE) is increased postpartum and contributes to important morbidity and mortality. While there have been advances in evaluating diagnostic algorithms for suspected VTE during pregnancy, there is limited data for postpartum individuals.

OBJECTIVE

We conducted a scoping review to describe and evaluate diagnostic strategies used to investigate suspected VTE in postpartum individuals.

METHODS

A comprehensive search strategy was conducted in Ovid MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (January 1, 2000-September 30, 2022) to identify original articles that reported on diagnostic strategies in postpartum individuals with suspected VTE. We extracted demographics, clinical decision rules used, D-dimer and imaging completed, including test performance and VTE outcomes.

RESULTS

A total of 13 studies conducted across 11 countries with separate postpartum data were included for 759 individuals with suspected PE (n = 634) or DVT (n = 125), including unpublished data (n = 251). Among those with suspected PE, computed tomography pulmonary angiography was conducted more commonly (n = 522) than ventilation-perfusion scans (n = 69), with PE positivity rates that ranged from 4 %-27.6 % and 0-50 % across studies, respectively. Among 131 postpartum individuals with suspected PE who had a D-dimer measured, only 4.6 % (6/131) had a negative D-dimer test. For postpartum individuals with suspected DVT, the most common diagnostic test was compression ultrasonography (positivity rate 12.2 %-18.6 %). There were limited retrospective data evaluating the clinical decision rules.

CONCLUSIONS

There are heterogeneous approaches globally in the diagnosis of suspected postpartum VTE. Limited high-quality data available underscores the need for more robust evidence to inform clinical practice.

High and intermediate risk pulmonary embolism in the ICU

Pulmonary embolism (PE) is a common and important medical emergency, encountered by clinicians across all acute care specialties. PE is a relatively uncommon cause of direct admission to the intensive care unit (ICU), but these patients are at high risk of death. More commonly, patients admitted to ICU develop PE as a complication of an unrelated acute illness. This paper reviews the epidemiology, diagnosis, risk stratification, and particularly the management of PE from a critical care perspective. Issues around prevention, anticoagulation, fibrinolysis, catheter-based techniques, surgical embolectomy, and extracorporeal support are discussed.

Diagnostic test accuracy of D-dimer with or without a clinical decision rule in peripartum patients with suspected venous thromboembolism: A systematic review and meta-analysis

BACKGROUND

Pregnancy and the peripartum period is a hypercoagulable state increasing the risk of venous thromboembolism (VTE). There may be a role in utilising D-dimer in the peripartum setting.

AIMS

The purpose of this review was to summarise the latest evidence regarding the diagnostic accuracy of D-dimer in the peripartum setting with or without the addition of clinical decision rules.

METHODS

We searched PubMed and CENTRAL databases to identify articles that included studies of women who had suspected VTE, underwent a D-dimer index test to rule out VTE and where radiological imaging or clinical follow-up, to a minimum of 30 days, was used as the reference standard.

RESULTS

We included 11 studies in the systematic review and meta-analysis. The log diagnostic odds ratio (DOR) for identifying VTE using D-dimer was 1.56 (95% confidence interval (CI) 0.59-2.52). The pooled sensitivity was 87% (95% CI 76.8-93%), specificity was 63.2% (95% CI 47.1-76.7%), and the area under receiver operator characteristic (ROC) curves was 0.76. We included four studies evaluating D-dimer combined with YEARS to detect VTE. The log DOR for identifying VTE using D-dimer combined with YEARS was 1.13 (95% CI 0.005-2.25). The pooled sensitivity was 89.8% (95% CI 60.2-98.1%), specificity was 65.7% (95% CI 54.7-75.2%) and the area under ROC for studies included with the YEARS clinical decision rule was 0.49.

CONCLUSION

This review highlighted that D-dimer use in the peripartum period for detection of VTE had a high sensitivity and high DOR but a poor area under ROC, which may limit its use in clinical practice.

Effect of domestic COVID-19 vaccine on the plasma D-dimer levels of early pregnant women in China

Objective

To investigate the effect of COVID-19 vaccination on plasma D-dimer levels in early pregnant women.

Methods

A total of 834 early pregnant women(gestational age ≤ 13 weeks), who visited Northwest Women and Children's Hospital between December 2020 and April 2022, were selected. There were 696 women in the healthy group (group A) and 138 in the group with a history of adverse pregnancy and childbirth (group B). The plasma D-dimer levels of all participants were tested, and the COVID-19 vaccine history of all participants was collected using a survey questionnaire.

Results

The plasma D-dimer levels did not differ between group A and the group B (p = 0.1327). In the group A, 470 were vaccinated and 226 were unvaccinated. The D-dimer levels of vaccinated individuals were lower than those of unvaccinated individuals (p = 0.0047). In the group B, 84 were vaccinated and 54 were unvaccinated; no difference in D-dimer levels was found between the vaccinated and unvaccinated individuals (p = 0.0542). In the group A, the D-dimer levels of the unvaccinated group were not different from those of women vaccinated with one dose (p = 0.208), but they were higher than those who received two doses (p = 0.019) or three doses (p = 0.003). And, no significant difference in D-dimer levels was found among women who received different vaccine brands and with different vaccination times.

Conclusion

This study preliminarily indicates that COVID-19 vaccination does not increase D-dimer levels in early pregnant women.

Venous Thromboembolism in Pregnancy: Challenges and Solutions

Venous thromboembolism (VTE) is a serious medical condition that can lead to severe morbidity and mortality, making it a significant public health concern. VTE is a multifactorial condition that results from the interaction of genetic, acquired, and environmental factors. Physiological changes during pregnancy increase the risk of VTE as they express Virchow's triad (increased coagulation factors, decreased fibrinolysis, trauma, and venous stasis). Moreover, pregnancy-related risk factors, such as advanced maternal age, obesity, multiple gestations, and cesarean delivery, further increase the risk of VTE. Managing VTE in pregnancy is challenging due to the complexity of balancing the risks and benefits of anticoagulant therapy for both the mother and the fetus. A multidisciplinary approach involving obstetricians, hematologists, and neonatologists, is necessary to ensure optimal outcomes for both the mother and baby. This review aims to discuss the current challenges associated with VTE in pregnancy and identify potential solutions for improving outcomes for pregnant women at risk for VTE.

Trimester-specific reference intervals and profile of coagulation parameters for Chinese pregnant women with diverse demographics and obstetric history: a cross-sectional study

BACKGROUND

Owing to the changes in childbirth policy in China, this work aimed to update the trimester-specific reference intervals (RIs) for Chinese pregnant women with diverse demographics and obstetric history. This study also investigated how advanced maternal age (AMA) (> 35 years old), gravity, and parity influence gestational coagulation parameters.

METHODS

In this prospective cross-sectional study, five coagulation parameters were measured using assays provided by Roche diagnostics on Cobas t 711: prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (Fib), and D-dimer, and the trimester-specific 2.5th -97.5th and 95th (D-dimer only) percentiles RIs were established accordingly. Linear regressions were undertaken to analyze the association with demographic characteristics and obstetric history for each parameter.

RESULTS

893 eligible pregnant women in different trimesters and at AMA/non-AMA and 275 non-pregnant healthy women were enrolled. For the first, second, and third trimester, respectively, RIs were as follows: APTT (s): 24.8-35.7, 24.6-34.1, and 23.5-34.7; TT (s): 14.4-17.3, 14.1-16.7, and 14.2-17.5; PT (s): 8.30-10.20, 8.00-9.77, and 7.92-9.57; PT-INR: 0.86-1.06, 0.83-1.02, and 0.82-0.98; Fib (g/L): 2.76-4.97, 3.14-5.31, and 3.44-5.93; D-dimer (µg/ml): 0-0.969, 0-2.14, and 0-3.28. No statistically significant differences were observed in TT, D-dimer, and APTT between the AMA and non-AMA women, while PT and PT-INR were shorter and Fib was higher in the AMA group. The association of gravidity and parity with each coagulation parameter is statistically significant (p < 0.05). PT and PT-INR were shortened and D-dimer decreased as gravidity increased. Longer PT and PT-INR, shorter APPT, higher D-Dimer, and lower Fib were associated with increasing parity.

CONCLUSIONS

This work updated the gestational coagulation profiles of Chinese pregnant women and established trimester-specific RIs accordingly. Establishing specific RIs based on AMA, parity, and gravidity might not be necessary.

Specific changes and clinical significance of plasma D-dimer during pregnancy and puerperium: a prospective study

BACKGROUND

Pregnant and puerperal women are high-risk populations for developing venous thromboembolism (VTE). Plasma D-dimer (D-D) is of good value in the diagnosis of exclusion of VTE in the nonpregnant population. Since there is no consensus reference range of plasma D-D applicable to pregnant and puerperal women, the application of plasma D-D is limited. To investigate the change characteristics and the reference range of plasma D-D levels during pregnancy and puerperium and to explore the pregnancy- and childbirth-related factors affecting plasma D-D levels and the diagnostic efficacy of plasma D-D for excluding VTE during early puerperium after caesarean section.

METHODS

A prospective cohort study was conducted with 514 pregnant and puerperal women (cohort 1), and 29 puerperal women developed VTE 24-48 h after caesarean section (cohort 2). In cohort 1, the effects of the pregnancy- and childbirth-related factors on the plasma D-D levels were analyzed by comparing the differences in plasma D-D levels between different groups and between different subgroups. The 95th percentiles were calculated to establish the unilateral upper limits of the plasma D-D levels. The plasma D-D levels at 24-48 h postpartum were compared between normal singleton pregnant and puerperal women in cohort 2 and women from the cesarean section subgroup in cohort 1, binary logistic analysis was used to analyze the relevance between plasma D-D level and the risk of VTE developing 24-48 h after caesarean section, and a receiver operating characteristic (ROC) curve was used to assess the diagnostic efficacy of plasma D-D for excluding VTE during early puerperium after caesarean section.

RESULTS

The 95% reference ranges of plasma D-D levels in the normal singleton pregnancy group were ≤ 1.01 mg/L in the first trimester, ≤ 3.17 mg/L in the second trimester, ≤ 5.35 mg/L in the third trimester, ≤ 5.47 mg/L at 24-48 h postpartum, and ≤ 0.66 mg/L at 42 days postpartum. The plasma D-D levels of the normal twin pregnancy group were significantly higher than those of the normal singleton pregnancy group during pregnancy (P < 0.05), the plasma D-D levels of the GDM group in the third trimester were significantly higher than those of the normal singleton pregnancy group (P < 0.05). The plasma D-D levels of the advanced age subgroup at 24-48 h postpartum were significantly higher than those of the nonadvanced age subgroup (P < 0.05), and the plasma D-D levels of the caesarean section subgroup at 24-48 h postpartum were significantly higher than those of the vaginal delivery subgroup (P < 0.05). The plasma D-D level was significantly correlated with the risk of VTE developing at 24-48 h after caesarean section (OR = 2.252, 95% CI: 1.611-3.149). The optimal cut-off value of plasma D-D for the diagnosis of exclusion of VTE during early puerperium after caesarean section was 3.24 mg/L. The negative predictive value for the diagnosis of exclusion of VTE was 96.1%, and the area under the curve (AUC) was 0.816, P < 0.001.

CONCLUSIONS

The thresholds of plasma D-D levels in normal singleton pregnancy and parturient women were higher than those of nonpregnant women. Plasma D-D had good value in the diagnosis of exclusion of VTE occurring during early puerperium after caesarean section. Further studies are needed to validate these reference ranges and assess the effects of pregnancy- and childbirth-related factors on plasma D-D levels and the diagnostic efficacy of plasma D-D for excluding VTE during pregnancy and puerperium.

Noninvasive diagnostic work-up for suspected acute pulmonary embolism during pregnancy: a systematic review and meta-analysis of individual patient data

BACKGROUND

Few studies evaluated the performance of noninvasive diagnostic strategies for suspected acute pulmonary embolism (PE) in pregnant women.

OBJECTIVES

The aim of this study was to establish the safety and efficiency of the Wells rule with fixed and adapted D-dimer threshold, and the YEARS algorithm, combined with compression ultrasonography (CUS), in pregnant women with suspected PE in an individual patient data meta-analysis.

METHODS

We performed a systematic review to identify prospective diagnostic management studies in pregnant women with suspected PE. Primary outcomes were safety, defined as the failure rate, ie, the 3-month venous thromboembolism (VTE) incidence after excluding PE without chest imaging, and efficiency, defined as the proportion of patients in whom chest imaging could be avoided.

RESULTS

We identified 2 relevant studies, of which individual patient-level data were analyzed in a fixed-effect meta-analysis, totaling 893 pregnant women. The Wells rule with fixed and adapted D-dimer threshold as well as the YEARS algorithm could safely rule out acute PE (failure rate, 0·37%-1·4%), but efficiency improved considerably when applying pretest probability-adapted D-dimer thresholds. The efficiency of bilateral CUS was limited (2·3% overall; number needed to test 43), especially in patients without symptoms of deep-vein thrombosis (efficiency 0·79%; number needed to test 127).

CONCLUSION

This study supports the latest guideline recommendations (European Society of Cardiology 2019) to apply pretest probability assessment and D-dimer tests to rule out PE in pregnant women. From an efficiency perspective, the use of a strategy with pretest probability-adapted D-dimer threshold is preferred. The yield of CUS was very limited in patients without concomitant symptoms of deep-vein thrombosis.

Associations Between Mean Platelet Volume and Risk of Deep Vein Thrombosis: A Mendelian Randomization Study and a Retrospective Study

Objective

In this study, it was intended to explore the causal association between mean platelet volume (MPV) and risk of deep vein thrombosis (DVT) using a two-sample Mendelian randomization (MR) analysis and a retrospective study.

Methods

This study applied two-sample MR analysis to estimate the causal association between MPV and risk of DVT. Twenty-one single nucleotide polymorphisms (SNPs) were selected as genetic variants from two independent consortiums cohorts (p-value <5×10^-8, linkage disequilibrium r²<0.1). Inverse variance weighted (IVW), MR-egger method and weighted median were performed. A retrospective study was also conducted to verify the associations identified from the MR study.

Results

The MR analysis demonstrated that genetically predicted higher MPV was associated with significantly lower risk of DVT (OR 0.982, 95% CI = 0.967-0.998, P = 0.023), with the consistent result in weighted median and MR-Egger. There was no directional horizontal pleiotropy in the method of MR-Egger regression (intercept=2.9e-04, P = 0.194). There was no single SNP was found to strongly drive the combined causal effect in the leave-one-out sensitivity analysis. Additionally, the similar result was observed in the retrospective study.

Conclusion

This study suggested that MPV was negatively associated with the risk of DVT. More basic researches are needed in the future to explore its specific mechanism.

Cardiovascular Complications of Pregnancy

The physiologic changes in pregnancy predispose the pregnant patient to a variety of potential cardiovascular complications. In this article, we discuss the major cardiovascular disorders of pregnancy and their management, highlight specific diagnostic challenges, and discuss new developments in the field. Topics covered in this article include venous thromboembolism, acute myocardial infarction, peripartum cardiomyopathy, and aortic dissection.

Diagnostic value of plasma D-dimer and serum lipoprotein phospholipase A2 in patients with cerebral small vessel disease and their association with severity of the disease

OBJECTIVE

To determine the diagnostic value of plasma D-dimer (DD) and serum lipoprotein phospholipase A2 (Lp-PLA2) in patients with cerebral small vessel disease (CSVD) and their association with severity of the disease.

METHODS

In this retrospective analysis, 84 patients with CSVD treated in Shangqiu First People's Hospital from February 2020 to November 2021 were included in the study group, and 75 healthy individuals were assigned into the control group. The DD and Lp-PLA2 levels in the two groups were compared, and the diagnostic value of the two in CSVD was evaluated via receiver operating characteristic (ROC) curves. Patients were assigned to a mild group or a severe group based on Fazekas scale scores. Then, the two groups were compared in terms of the DD and Lp-PLA2 levels, and the association of the two with the severity of CSVD was determined through ROC curves. With the Montreal cognitive assessment (MoCA) scale, the patients were assigned to a cognitive impairment group or a non-cognitive impairment group. Then the two groups were compared in terms of the DD and Lp-PLA2 levels, and the association of the two with the cognitive function of CSVD patients was also determined by ROC curves.

RESULTS

The research group showed higher DD and Lp-PLA2 levels than the control group; the severe group showed higher DD and Lp-PLA2 levels than the mild group; the cognitive impairment group showed higher DD and Lp-PLA2 levels than the non-cognitive impairment group (all P < 0.001). The areas under the curves (AUCs) of DD and Lp-PLA2 in CSVD diagnosis were 0.902 and 0.907, respectively; the AUCs of DD and Lp-PLA2 in CSVD severity determination were 0.747 and 0.704, respectively; the AUCs of DD and Lp-PLA2 in cognitive impairment diagnosis were 0.736 and 0.725, respectively.

CONCLUSION

Plasma DD and Lp-PLA2 possess good diagnostic value in patients with CSVD, and also has certain clinical value in diagnosing patients' severity and cognitive impairment.

The High Expression of Adhering and Circulating Integrin Serves as a Diagnostic Marker in Venous Thromboembolism

Objective

To investigate the diagnostic value of circulating integrins β1, 2, and 3 in venous thrombosis (VTE).

Materials and Methods

A total of 474 VTE patients and 306 patients with nonhigh risk for VTE as the control group were studied. Levels of adhering integrins β1, 2, and 3 were detected by flow cytometry. Levels of circulating integrins β1, 2, and 3 in serum were measured by enzyme-linked immunosorbent assay.

Results

We found that integrins β1, 2, and 3 were expressed highly both in serum and on the surface of leukocytes and platelets in venous thromboembolism. The levels of circulating integrins β1, 2, and 3 are positively correlated with adhering integrins. It showed excellent clinical diagnostic performance of circulating integrins β1, 2, and 3 in venous thromboembolism.

Conclusions

Integrin subunit β can be used as a diagnostic marker with high sensitivity and specificity for venous thromboembolism.

Diagnosis of venous thromboembolism in pregnancy: a review of current guidelines

Venous thromboembolic disease (VTE) is the leading cause of maternal death throughout the developed world. International and national guidance for the diagnosis and management of VTE in pregnancy is varied and limited, which can result in problems in clinical practice. The imaging challenges of VTE in the general population are challenging but become more complex in pregnancy due to the physiological changes in the circulatory system, which alter clinical judgment and test performance. As an additional factor, the relative radiation risks to the mother and fetus arising from diagnostic tests need to be assessed and communicated to the patient in a clear and understandable way. The purpose of this review is fourfold. We propose to review and summarise the current imaging guidelines available for this condition; critically review the evidence base within the current literature; address the issues of test performance of imaging examinations used for VTE in pregnancy; and address the question of radiation risk and how to communicate this information to patients.

Brain-Derived Neurotrophic Factor Expression in Patients with Acute Pulmonary Embolism Compared to the General Population: Diagnostic and Prognostic Implications

(1) Background: Pulmonary embolism (PE) is a severe condition, representing the third most important cardiovascular cause of death after myocardial infarction and stroke. Despite the use of clinical pre-test probability scores, D-dimer measuring, and computer tomography pulmonary angiography (CTPA), PE diagnosis remains a challenge. Brain-derived neurotrophic factor (BDNF) is the most important member of the neurotrophin family, which has also been shown to be involved in the physiopathology of cardiovascular conditions such as heart failure and myocardial infarction. In this study, we aimed to assess the BDNF expression in patients with acute PE compared to the general population, and to also investigate its diagnostic and prognostic role. (2) Methods: We conducted a single center prospective study, which included 90 patients with PE and 55 healthy volunteers. Clinical and paraclinical parameters, together with plasma levels of BDNF, were evaluated in all patients after admission. (3) Results: The plasma levels of BDNF were significantly lower in the PE patients compared with the control group (403 vs. 644 pg/mL, p < 0.001). ROC analysis revealed an AUC of 0.806 (95% CI 0.738−0.876, p < 0.001) and a cut-off value of 564 pg/mL, which associated a sensitivity of 74.4% and a specificity of 78.2% for PE. Low BDNF levels also correlated with prognostic markers of PE, such as PESI score (p = 0.023), NT-proBNP (p < 0.01), right ventricular diameter (p = 0.029), and tricuspid annular plane systolic elevation (p = 0.016). Moreover, we identified a decreased BDNF expression in patients with high-risk PE (p < 0.01), thrombolytic treatment (p = 0.01), and patients who died within 30 days (p = 0.05). (4) Conclusions: Our study revealed that plasma BNDF is significantly lower in patients with PE when compared with the general population, and may be considered as a promising biomarker in complementing the current diagnostic tools for PE. Furthermore, low levels of BDNF might also be used to predict a poor outcome of this condition.

Diagnosis of Pulmonary Embolism during Pregnancy

Although rare, pulmonary embolism (PE) remains one of the most common causes of severe maternal morbidity and mortality during pregnancy. Among pregnant women with suspected PE, the prevalence of confirmed disease is far lower than in the general population, reflecting the fear of missing the diagnosis and a low threshold to suspect PE in this setting. Two prospective management outcome trials have recently assessed two different diagnostic algorithms based on the assessment of clinical probability, D-dimer, venous compression ultrasonography of the lower limbs (CUS), and computed tomography pulmonary angiography (CTPA). Both demonstrated the safety of such strategies to exclude PE, with a very low failure rate defined as the rate of subsequent 3-month venous thromboembolism in women left untreated after a negative work-up. These studies were also the first to prospectively demonstrate the safety of negative D-dimer associated with a clinical prediction rule to exclude PE without any chest imaging. Pregnant women are known to be a subgroup at particularly high risk of inappropriate diagnostic management, so the implementation of such validated diagnostic strategies in clinical practice should represent a high priority goal.

D‐dimer testing in clinical practice in the era of COVID‐19

D‐dimer is a fragment of crosslinked fibrin resulting from plasmin cleavage of fibrin clots and hence an indirect biomarker of the hemostatic system activation. Early in the coronavirus disease 2019 (COVID‐19) pandemic, several studies described coagulation disorders in affected patients, including high D‐dimer levels. Consequently, D‐dimer has been widely used in not‐yet‐approved indications. Ruling out pulmonary embolism and deep vein thrombosis in patients with low or intermediate clinical suspicion is the main application of D‐dimer. D‐dimer is also used to estimate the risk of venous thromboembolism recurrence and is included in the ISTH algorithm for the diagnosis of disseminated intravascular coagulation. Finally, numerous studies identified high D‐dimer levels as a biomarker of poor prognosis in hospitalized patients with COVID‐19. This report focuses on validated applications of D‐dimer testing in patients with and without COVID‐19.

[Clinical Confusion Concerning Increased D-Dimer Value during Pregnancy]

Plasma D-dimer, a special cross-linked fibrin derivative, is produced when fibrin is degraded by plasminase. During pregnancy, D-dimer increases along with the increase of gestational age, and the reference value of plasma D-dimer (≤0.5 mg/L) traditionally used for the screening of venous thrombosis in the normal population is not applicable to the pregnant population. Due to the lack of uniform D-dimer detection methods or measurement units, there is currently no unified D-dimer reference values for pregnancy or puerperium. Each region or laboratory should establish its own pregnancy D-dimer reference value for different gestational weeks through blood coagulation function testing of large numbers of samples of different gestational periods. More and more studies have been conducted to investigate the association between D-dimer and venous thromboembolism (VTE) during pregnancy, gestational hypertensive disorders (GHD) and pregnancy outcome. We reviewed, herein, the generation and measurement of D-dimer, the reference values of D-dimer during normal pregnancy, and the association between D-dimer and some pathological pregnancies, intending to help clinicians develop a more thorough understanding of D-dimer during pregnancy.

Diagnostic Management of Pregnant Women With Suspected Pulmonary Embolism

Pulmonary embolism (PE) is one of the most common causes of severe morbidity and mortality during pregnancy. PE diagnosis during pregnancy remains a true challenge for all physicians, as many of the symptoms and signs associated with PE are often reported during physiological pregnancy. The fear of missing a PE during pregnancy leads a low threshold of suspicion, hence to a low prevalence of confirmed PE among pregnant women with suspected PE. This means that most pregnant women with suspected PE do not have the disease. Until recently, international guidelines suggested thoracic imaging in all pregnant women with suspected PE. Two recent prospective management outcome studies based on clinical probability assessment, D-dimer measurement, venous compression ultrasonography of the lower limbs (CUS) and computed tomography pulmonary angiography (CTPA) proved the safety of such strategies, with a very low failure rate. For the first time, these studies also demonstrated that the association of a clinical prediction rule and D-dimer measurement allowed a safe exclusion of PE in a significant proportion of pregnant women, without the need for radiating imaging tests. These two prospective studies pave the way to further improvements in the diagnostic strategies. Indeed, both specific clinical prediction rules and possibly D-dimer cutoffs adapted to pregnant women could help to further reduce the proportion of patients needing thoracic imaging. As an imaging test will still ultimately be necessary in a significant proportion of women, further technical advances in CT scans protocols could reduce the radiation dose to both the fetus and the mother, an important step to reassure clinicians. Finally, educational efforts should be encouraged in the future to pass the challenge of implementing these validated diagnostic strategies in everyday clinical practice.

Investigation and Application of Risk Factors of Macrosomia Based on 10,396 Chinese Pregnant Women

OBJECTIVE

The objective of this study was to examine the association of fetal macrosomia with maternal D-dimer and blood lipid levels, and explore whether D-dimer and blood lipids, either alone or in combination with traditional risk factors at hospital birth, could be used to predict subsequent delivery of macrosomia.

METHODS

From April 2016 to March 2017, 10,396 women with singleton pregnancy giving birth at around 28-41 weeks of gestation were recruited into the present study. D-dimer and blood lipid levels were measured at hospital admission; and data on birth outcomes were obtained from hospital records.

RESULTS

Multivariate logistic regression analysis showed that D-dimer, triglyceride and HDL-C levels were significantly associated with risk of macrosomia independent of traditional risk factors (for D-dimer: adjusted OR: 1.33, 95% CI, 1.23-1.43; for triglyceride: adjusted OR: 1.14, 95% CI, 1.05-1.23; for HDL-C: adjusted OR: 0.35, 95% CI, 0.24-0.51, all P <0.01). More importantly, incorporating D-dimer and blood lipids into the traditional model significantly increased the area under curve (AUC) for prediction of macrosomia (0.783 vs. 0.811; P <0.01).

CONCLUSION

Our study demonstrates that maternal D-dimer, triglyceride, and HDL-C levels before hospital birth could be significant and independent of risk factors of fetal macrosomia. Therefore, combining D-dimer and blood lipid levels with traditional risk factors might improve the ability to predict macrosomia in gestational diabetes mellitus and normal pregnancies.