Venous thromboembolism in pregnancy

Comprehensive review of thrombophilia: pathophysiology, prevalence, risk factors, and molecular diagnosis

Thrombophilia, characterized by an imbalance between fibrinolysis and coagulation leading to inappropriate blood clotting, is a significant medical condition. The CDC has designated it as an underdiagnosed, serious, and potentially preventable disorder, contributing to an estimated 600,000-900,000 cases and 100,000 deaths annually in the United States. These figures surpass the combined annual mortality of AIDS, breast cancer, and motor vehicle accidents. The pathogenesis of thrombophilia involves complex interactions between genetic predispositions, such as mutations in Factor V Leiden, Factor II, MTHFR, and Serpine-1, and environmental factors, including unhealthy lifestyles, prolonged hospitalization, obesity, and cancer. Prevalence of specific genetic mutations varies across populations. Additional risk factors include age, family history, and pregnancy, with recent attention to increased susceptibility in SARS-CoV-2 infection. While molecular diagnostic techniques are available, there remains a need for robust, cost-effective, and accurate screening methods for large populations. This systematic review provides an updated overview of thrombophilia, encompassing pathophysiology, epidemiology, genetic and environmental risk factors, coagulation cascade, population-specific mutation prevalence, and diagnostic approaches. By synthesizing clinical and molecular evidence, this review aims to guide researchers, hematologists, and clinicians in the diagnosis and management of thrombophilia.

Association Between Obesity and Thrombosis During Pregnancy and the Postpartum Period: A Case-Control Study From a Tertiary Care Center in Kerala, India

Background Obesity is postulated to be a high-risk factor for thrombosis along with the inherent hypercoagulability of pregnancy. The Confidential Review of Maternal Deaths (CRMD) found that thrombosis was one of the major causes of maternal deaths in Kerala. This study investigates the major risk factor - obesity and its association with thrombosis in our study setting, along with other risk factors. Obesity, being a modifiable risk factor, can thus be targeted to decrease maternal morbidity and mortality for a better pregnancy outcome. This study sought to examine the association between obesity and thrombosis during pregnancy and the postpartum period in a tertiary care center in Kerala, India, while also identifying other risk factors that may contribute to thrombotic events in this population. Methodology A hospital-based case-control study was conducted at Government Medical College, Thiruvananthapuram, Kerala, India, from March 2017 to September 2018. The study population comprised 42 cases diagnosed with thrombotic events during pregnancy and the postpartum period, including deep vein thrombosis (DVT), cortical venous thrombosis (CVT), and pulmonary thromboembolism (PTE). Using consecutive sampling from the hospital's labor register, 84 controls were selected, maintaining a case-to-control ratio of 1:2. Detailed clinical information was collected through direct patient interviews and medical record reviews. Body mass index (BMI) was calculated using pre-pregnancy weight and height measurements. Variables assessed included demographic characteristics, obstetric history, socioeconomic status, blood group, gestational age at thrombosis, type and location of thrombosis, risk factors, comorbidities, clinical manifestations, treatment modalities, and outcomes. Results The study demonstrated a significant association between obesity and thrombotic events in pregnancy and postpartum periods. In the case group, 21 patients (50.0%) presented with Class I obesity, and three patients (7.1%) with Class II obesity. The control group included 14 patients (16.7%) with Class I obesity and no patients (0%) with Class II obesity, revealing a significant difference in BMI class distribution between groups (χ2=25.979, p<0.001). Among the cases, DVT was the predominant presentation in 29 patients (69.0%), primarily affecting the ileo-femoral region in 26 patients (61.9%). CVT occurred in 12 patients (28.6%). Of the DVT patients, obesity was present in 17 patients (58.6%) compared to 12 non-obese patients (41.4%), showing statistical significance (χ²=14.488, p=0.001). Additional significant risk factors were identified in the study group: period of immobility affected five patients (11.9%), puerperal infection was present in five patients (11.9%), and antiphospholipid antibodies (APLA) positivity was found in five patients (11.9%). All these risk factors showed statistically significant differences compared to controls (p=0.001). Treatment outcomes were favorable, with 40 patients (95.2%) achieving either complete resolution or showing improvement. Conclusion Obesity significantly increases pregnancy-associated thrombosis risk, particularly DVT in the ileo-femoral region. Additional factors like immobility, puerperal infection, and APLA positivity contribute to thrombosis development. While treatment outcomes are favorable, early recognition and management are crucial, especially in women with multiple risk factors.

Epidemiology, Etiology, and Pathophysiology of Pulmonary Embolism

Over the last 20 years, there has been a progressive increase in the incidence of pulmonary embolism (PE) diagnosis in the United States, Europe, and Australia. Increased use of computed tomography pulmonary angiography has likely contributed in part to this rising incidence. However, it is pertinent to note that the burden of comorbidities associated with PE, such as malignancy, obesity, and advanced age, has also increased over the past 20 years. Time-trend analysis in North American, European, and Asian populations suggests that mortality rates associated with PE have been declining. The reported improved survival rates in PE over the past 20 years are likely, at least in part, to be the result of better adherence to guidelines, improved risk stratification, and enhanced treatment. Factors contributing to the development of venous thromboembolism (VTE) include stasis of blood, hypercoagulability, endothelial injury, and inflammation. In 70 to 80% of cases of PE, the thrombi embolizes from the proximal deep veins of the lower extremities and pelvis. Strong risk factors for VTE include lower extremity fractures and surgeries, major trauma, and hospitalization within the previous 3 months for acute myocardial infarction or heart failure with atrial fibrillation. Acute PE causes several pathophysiological responses including hypoxemia and right ventricle (RV) failure. The latter is a result of pulmonary artery occlusion and associated vasoconstriction. Hemodynamic compromise from RV failure is the principal cause of poor outcome in patients with acute PE.

Peripartum Cardiogenic Shock and Mechanical Circulatory Support

Despite remarkable improvements in the past two decades, the annual cardiovascular mortality rate has remained higher for women than for men. Pregnant women represent an underinvestigated population in clinical research, and the mechanisms of long-term cardiovascular complications in women with obstetric complications remain to be elucidated. Regarding advanced heart failure during pregnancy, interventional approaches are effective but still underutilised. Percutaneous mechanical circulatory support is a valuable option for peripartum cardiogenic shock, although its use during pregnancy is still limited. Survival rates have improved in recent years, but further emphasis on the importance of early recognition and initiation of heart failure treatment in this patient group is warranted. The aims of this review are to summarise the current literature on the implementation of mechanical circulatory support in cardiogenic shock during pregnancy and delivery and to understand the role of percutaneous ventricular assist devices in the management of such conditions.

Agreement between two scales used for assessing risk classification for thromboembolic events and the requirement of postpartum pharmacological prophylaxis

OBJECTIVES

To determine agreement in assessing the need for postpartum pharmacological prophylaxis between the scale of the Royal College of Obstetricians and Gynaecologists and the Colombian guideline scale in a Level IV institution in Bogota, Colombia.

MATERIAL AND METHODS

Diagnostic agreement study assembled on a cross-sectional study. The included population consisted of pregnant women with 24 or more weeks of pregnancy admitted between March 1 and April 30 of 2021 to a high complexity private institution in Bogotá, Colombia, for labor induction, in active labor, for elective cesarean section, or who required urgent cesarean section. Convenience sampling was used. Measured variables included demographics, risk factors, risk classification and pharmacological prophylaxis according to the two scales. The prevalence of risk factors for each scale was estimated and agreement regarding prophylaxis indication between the two scales was measured using the weighted kappa value.

RESULTS

Overall, 320 patients were included. According to the scale of the Royal College Obstetricians and Gynaecologists, 54.7 % patients were classified as low risk, 42.5 % as intermediate risk and 2.8 % as high risk. The Colombian scale classified 80 % of patients as low risk, 17.2 % as intermediate risk, 2.2 % as high risk, and 0.6 % as very high risk. The weighted kappa value for agreement regarding the indication was 0.47 (95 % CI: 0.38-0.56).

CONCLUSIONS

Agreement between the two scales to determine the need for postpartum pharmacological prophylaxis is moderate. Risk classification criteria for the Colombian scale should be validated in a second cohort. Moreover, the predictive ability of the Colombian guideline tool should be assessed at different cut-off points in terms of the consequences of false positive and false negative results.

Differences in the prevention and incidence of maternal venous thromboembolism according to the type of institution in Japan in 2018: A sub-analysis of national questionnaire surveillance

AIM

To clarify the relation between institutions capacity to manage venous thromboembolism (VTE) and its incidence in pregnant women throughout Japan.

METHODS

Among the 2299 institutions that received the surveillance questionnaire, 666 (29.0%) responded, after which data from 295 961 women who gave birth at those institutions in 2018 were analyzed. Incidences and characteristics of antepartum and postpartum VTE in perinatal medical centers (PMCs), general hospital with obstetric facilities (GHs), and maternal clinic with beds (MCs) were then determined.

RESULTS

The frequencies at which routine antepartum and postpartum thromboprophylaxis for high-risk women and routine transport to the more advanced medical institutions upon antepartum and postpartum pulmonary thromboembolism (PE) onset were performed differed significantly according to types of institution (PMCs: 92.4%, 96.2%, 23.8%, and 21.2%; GHs: 76.5%, 80.6%, 58.8%, and 54.1%; MCs: 29.2%, 41.7%, 96.5%, and 96.2%, respectively). Among the 295 961 women analyzed, 243 (0.082%) developed VTE. Incidences of antepartum VTE differed significantly according to institution types (PMCs: 106.4, GHs: 51.6, and MCs: 11.6 per 100 000 women). PMCs and GHs had significantly higher incidences of postpartum VTE compared to MCs (43.3 and 26.6 vs. 10.7 per 100 000 women, respectively), although PMCs and GHs had similar incidences. Among the four women (1.4%) who died due to VTE, three and one developed a PE in a PMC and MC, respectively.

CONCLUSIONS

PMCs had higher incidences of VTE despite their more frequent performance of thromboprophylaxis. Several pregnant women with higher risk of VTE transported to PMCs.

Venous thromboembolism risk and prophylaxis in hospitalized obstetric patients at a tertiary hospital in Accra, Ghana: A comparative cross-sectional study

OBJECTIVE

To determine the prevalence of venous thromboembolism risk and thromboprophylaxis among obstetric inpatients, comparing prenatal and postnatal women.

METHODS

We assessed 546 obstetric inpatients at the Korle-Bu Teaching Hospital for the prevalence study. Out of this number, 223 were recruited, comprising 111 prenatal and 112 postnatal mothers. A structured interviewer-administered questionnaire was used to obtain data on participants' venous thromboembolism risk, which was categorized into high, intermediate, and low using the Royal College of Obstetricians and Gynaecologists guidelines. Data on thromboprophylaxis were also obtained and analyzed. Values were considered statistically significant at p < 0.05.

RESULTS

Overall venous thromboembolism risk among the study population was 82/223 (36.8%). All patients at high risk were prenatal, 59/112 (52.7%) of postnatal mothers were at intermediate risk, compared with 20/111 (18.0%) of prenatal women (p < 0.001). Prevalence of thromboprophylaxis was 5/82 (6.1%). All prenatal high-risk patients received thromboprophylaxis, whereas only 2/20 (10.0%) of women with intermediate risk received thromboprophylaxis. The incidence of venous thromboembolism was 3/546 (0.6%) in the obstetric inpatients.

CONCLUSION

Our study found a high prevalence of venous thromboembolism risk among obstetric inpatients at the Korle-Bu Teaching Hospital. However, thromboprophylaxis was low. Further research is needed to audit recent practice of thromboprophylaxis and perinatal outcome.

Puerperal complications: pathophysiological mechanisms and main imaging findings

OBJECTIVE

Puerperium is the period during which the physiological changes that have taken place during pregnancy revert and the uterus involutes until it reaches its normal size. This is a period of intense systemic changes, and diagnosing complications in this period is a challenge for both gynecologists and radiologists. This paper reviews the complications that can occur during puerperium, classifying them according to the pathophysiological mechanisms involved: the prothrombotic state, hemodynamic and hormonal changes, rapid uterine growth, changes associated with endothelial damage (preeclampsia, eclampsia, and HELLP syndrome), and postoperative complications in patients undergoing cesarean sections.

CONCLUSION

Puerperal complications represent a diagnostic challenge. Understanding the pathophysiological mechanisms underlying these complications is fundamental for choosing the most appropriate imaging technique to ensure the correct diagnosis in each case.

Pulmonary embolism during pregnancy: a 17-year single-center retrospective MDCT pulmonary angiography study

OBJECTIVES

To determine the prevalence of pulmonary embolism (PE) and alternative diagnoses detected by computed tomography pulmonary angiography (CTPA) in pregnant women; and to assess changes over time regarding radiation dose, technical quality, and examination frequency.

MATERIALS AND METHODS

This retrospective study included all pregnant women referred for CTPA due to clinically suspected PE over 17 years. Two blinded radiologists reviewed the CTPAs in consensus with regard to PE, alternative diagnoses, and technical quality. We retrieved patient data regarding radiation dose metrics and associated clinical and laboratory parameters. Subgroup comparisons were performed (Wilcoxon and Kruskal-Wallis tests).

RESULTS

Of the 237 identified patients, 8 (3.3%) were excluded due to inadequate technical CTPA quality, and 229 patients were analyzed (mean age, 31.7 years; mean gestational age, 28 ± 7 weeks). The four different CT systems used over the study period had similar technical quality (p = 0.28). Of 229 patients 16 (7%) patients had PE, 144 (62.9%) had no abnormal findings, and 69 (30.1%) had an alternative diagnosis (consolidation, other pulmonary opacities, pleural effusion, and basal atelectasis). Gestational age, symptoms, and D-dimer levels were not significantly different between patients with or without PE (p > 0.05). Over time, radiation dose exposure decreased by 30% (p < 0.001), while the number of annual examinations increased by > 4-folds.

CONCLUSIONS

In pregnant women, CTPA rarely indicates PE and more often shows alternative diagnoses. Over 17 years, the use of CTPA in pregnancy has notably increased, while the radiation dose exposure has decreased by one third.

KEY POINTS

• The use of CTPA in pregnancy has steadily risen over the last 17 years • In pregnant women, CTPA rarely reveals PE and more often shows alternative diagnoses • Recent technical improvements have substantially decreased the radiation dose exposure inherent in CTPA without reducing diagnostic image quality.

Risk of venous thromboembolism in Chinese pregnant women: Hong Kong venous thromboembolism study

Background

Previous Caucasian studies have described venous thromboembolism in pregnancy; however, little is known about its incidence during pregnancy and early postpartum period in the Chinese population. We investigated the risk of venous thromboembolism in a "real-world" cohort of pregnant Chinese women with no prior history of venous thromboembolism.

Methods

In this observational study, 15,325 pregnancies were identified in 14,162 Chinese women at Queen Mary Hospital, Hong Kong between January 2004 and September 2016. Demographic data, obstetric information, and laboratory and imaging data were retrieved and reviewed.

Results

The mean age at pregnancy was 32.4±5.3 years, and the median age was 33 years (interquartile range, 29-36 yr). Pre-existing or newly diagnosed diabetes mellitus was present in 627 women (4.1%); 359 (0.7%) women had pre-existing or newly detected hypertension. There was a small number of women with pre-existing heart disease and/or rheumatic conditions. Most deliveries (86.0%) were normal vaginal; the remaining were Cesarean section 2,146 (14.0%). The incidence of venous thromboembolism was 0.4 per 1,000 pregnancies, of which 83.3% were deep vein thrombosis and 16.7% were pulmonary embolism. In contrast to previous studies, 66.7% of venous thrombosis occurred in the first trimester.

Conclusion

Chinese women had a substantially lower risk of venous thromboembolism during pregnancy and the postpartum period compared to that of Caucasians. The occurrence of pregnancy-related venous thromboembolism was largely confined to the early pregnancy period, probably related to the adoption of thromboprophylaxis, a lower rate of Cesarean section, and early mobilization.

CT and MR imaging findings of systemic complications occurring during pregnancy and puerperal period, adversely affected by natural changes

Dynamic physiological and anatomical changes for delivery may adversely induce various specific non-obstetric complications during pregnancy and puerperal period. These complications can be fatal to both the mother and the fetus, thus a precise and early diagnosis ensued by an early treatment is essential. Along with ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI) have assumed an increasing role in the diagnosis.

This article aims to discuss the pathophysiology of these complications, the indications for CT and MRI, and the imaging findings.

[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.

Protein Z variants associated with protein Z plasma levels and with risk of idiopathic recurrent miscarriage

Protein Z (PZ) deficiency due to anti-PZ autoantibodies and/or mutations in PZgene was linked with adverse pregnancy outcomes, including idiopathic recurrent miscarriage (IRM). We investigated the association of rs3024718, rs3024719, rs3024731, rs3024778, rs3024772, and rs3024735 (G79A) PZ variants and changes in PZ levels in 287 women with IRM, and 308 control women. Of the 6 single nucleotide polymorphisms (SNPs) analyzed, higher minor allele frequency of rs3024735 (G79A) and rs3024731 were seen in IRM cases than in control women. Significantly higher frequencies of rs3024735/G79A G/A and A/A (P< .001), rs3024719 G/A (P= .009), and rs3024731 A/A (P = .012), but not rs3024718 (P= .12), rs3024778 (P = .76), or rs3024772 (P= .27) genotype carriers were seen between IRM cases versus control women, respectively, and was linked with reduced PZ levels. Six-locus (rs3024718/rs3024719/rs3024778/rs3024731/rs3024735/rs3024772) PZhaplotypes analysis demonstrated increased frequency of GAGAAG and AGGTAG and reduced frequency of AGGTGC haplotypes in IRM cases, thereby conferring disease susceptibility and protective nature to these haplotypes, respectively. These results demonstrate that specific PZSNPs and haplotypes are significantly associated with IRM.

Prevention of venous thromboembolism in pregnancy: a review of guidelines, 2000-2011

INTRODUCTION

Pregnant women are four to five times more likely than nonpregnant women to develop venous thromboembolism (VTE). The aim of this review is to provide an overview of guidelines in the literature on VTE risk assessment, screening for thrombophilias, and thromboprophylaxis dissemination among pregnant women.

METHODS

We performed a review of the published literature to identify evidence-based guidelines published between the years 2000 and 2011. We searched for guidelines from U.S. and international organizations that identified clinically based practice recommendations to healthcare providers on how VTE risk should be assessed, thrombophilias screened, and thromboprophylaxis disseminated among pregnant women.

RESULTS

We found nine guidelines that met our requirements for assessing VTE risk and found seven guidelines addressing thrombophilia screening. Seven of the nine agreed that all women should undergo a risk factor assessment for VTE either in early pregnancy or in the preconception period. Seven of the nine agreed that pregnant women with more than one additional VTE risk factor be considered for thromboprophylaxis, and five of the seven groups addressing thrombophilia screening agreed that selected at-risk populations should be considered for thrombophilia screening.

CONCLUSIONS

There is some agreement between U.S. and international guidelines that women should be assessed for VTE risk during preconception and again in pregnancy. Although there is agreement that the general population of women should not be screened for thrombophilias, no agreement exists as to the clinical subgroups for which screening should be done.

[News on antithrombotic therapy and pregnancy]

OBJECTIVES

State of the art of antithrombotics and their use recommendations during pregnancy.

METHODS

A review

RESULTS

Aspirin and heparins remain the safest molecules during pregnancy, and oral anticoagulants are still used for mechanical valves. Heparinoids are the methods of choice in case of heparin-induced thrombopenia but other molecules could find their place: fondaparinux at first and possibly the direct thrombin inhibitors. Thrombolysis may be used in case of life-threatening incident. At present, the new oral forms can not be used during pregnancy

CONCLUSIONS

During pregnancy, all antithrombotics, except the oral forms, can be used, but the low molecular weight heparins replacing the unfractionated ones in the treatment and prevention of venous thromboembolism remain the treatment of choice.