Thrombophilias in Pregnancy

Iliac vein stenting and pregnancy

Venous stenting is the mainstay treatment of symptomatic iliofemoral venous outflow obstruction. However, because pregnancy and the postpartum period are hypercoagulable, concerns exist regarding stent placement in women of childbearing age. We performed a systematic review up to April 2023 of studies reporting on the performance of venous stents in women who subsequently became pregnant. The data collected included demographics, indication for stenting, stent characteristics, stent-related complications, incidence of venous thromboembolism, medical management during pregnancy, and follow-up. The indications for stenting included acute iliofemoral deep vein thrombosis in 39 patients (51%), nonthrombotic iliac vein lesions in 35 (46%), and post-thrombotic lesions in 2 patients. A total of 76 women with 87 subsequent pregnancies after stenting were included. Of the 76 women, 1 (1.14%) experienced stent occlusion, 2 (2.29%) developed asymptomatic nonocclusive in-stent thrombus, and 2 (2.29%) experienced permanent stent compression. The only patency loss occurred because of inadequate anticoagulation therapy in a patient with antiphospholipid antibodies. The two cases of permanent compression occurred in an arterial stent and a balloon-fenestrated Vici stent (Boston Scientific). Venous stents performed well through pregnancy and can be safely used in women of childbearing age. Given the increased risk of venous thromboembolism and the low bleeding risk, it is prudent to recommend anticoagulation therapy for all stented patients until more data are available.

Outcomes of dedicated iliac venous stents during pregnancy and postpartum

OBJECTIVE

The aim of this study was to assess the performance of dedicated iliac venous stents during subsequent pregnancy and postpartum, including stent patency and stent integrity, as well as incidence of venous thromboembolism and bleeding complications.

METHODS

This study included retrospective analysis of prospectively collected data of patients attending a private vascular practice. Women of child-bearing age who had received dedicated iliac venous stents were included in a surveillance program and then, for any subsequent pregnancies, followed the same pregnancy care protocol. This included an antithrombotic regime of 100 mg aspirin daily until gestation week 36, and subcutaneous enoxaparin at a dose dependent on risk of thrombosis: low-risk patients, those stented for non-thrombotic iliac vein lesion, received a prophylactic dose of 40 mg/day from the third trimester; high-risk patients, those stented for thrombotic indication, received a therapeutic dose of 1.5 mg/kg/day from the first trimester. All women underwent follow-up with duplex ultrasound assessment of stent patency during pregnancy and at 6 weeks postpartum.

RESULTS

Data was analyzed for a total of 10 women and 13 post-stent pregnancies. Stents were placed for non-thrombotic iliac vein lesions in seven patients, and for post-thrombotic stenoses in three patients. All stents were dedicated venous stents, and four crossed the inguinal ligament. All stents remained patent during pregnancy, at 6 weeks postpartum, and latest follow-up (median time post-stent, 60 months). There were no cases of deep vein thrombosis or pulmonary embolism, and no bleeding complications. There was only one reintervention case due to in-stent thrombus, and one case of asymptomatic stent compression.

CONCLUSIONS

Dedicated venous stents performed well through pregnancy and post-partum. A protocol including the use of low dose antiplatelets in combination with anticoagulation at either a prophylactic or therapeutic dose depending on the patient's risk profile appears safe and effective.

Association between factor V Leiden mutation and recurrent pregnancy loss in the middle east countries: a Newcastle-Ottawa meta-analysis

PURPOSE

Heritable thrombophilia is a category of genetic disorders of the coagulation cascade with the increasing risk of thrombus formation and recurrent pregnancy loss (RPL). Factor V Leiden (FVL) (R506Q) mutation is the most common genetic cause of deep venous thrombosis, but its association with RPL has been inconsistent in studies arising from non-Western countries. The present metanalysis was aimed to determine whether an association exists between FVL and RPL in the Middle East.

METHODS

We searched PubMed, MEDLINE Web of Science, Scopus, and Embase, evaluating the association between the FVL and RPL. The Middle East countries (Bahrain, Cyprus, Egypt, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, The State  of Palestine, Syria, Turkey, The United Arab Emirates, and Yemen) were evaluated in succession. Raw data were extracted, and 19 case-control studies were included in our final analysis.

RESULTS

Overall, 2513 cases and 1836 controls in the Middle East showed a prevalence of FVL mutation as 12.6% and 4.9% in patients and controls, respectively. To evaluate the relationship between FVL mutation and RPL, we used Forest plot (random effect model) with the overall random OR of 2.37 (CI 95%: 1.50-3.75). FVL mutation was associated with a higher risk of RPL. In Iran, the OR was 1.90 (95% CI 1.04-3.45), and in Turkey, the OR was 3.01 (95% CI 1.10-8.23).

CONCLUSION

The results of our study support an association between FVL mutation status and RPL in women of the Middle East countries. It is recommended that specific policies include comprehensive testing for FVL mutation as a standard of care in women of the Middle East region with unexplained RPL.

Venous thromboembolism does not share strong familial susceptibility with pre-eclampsia/eclampsia: a nationwide family study in Sweden

OBJECTIVE

Genetic variants associated with venous thromboembolism (VTE) have been suggested to be involved in the pathogenesis of pre-eclampsia/eclampsia (PEC/EC). This nationwide study aimed to determine whether VTE shares familial susceptibility with PEC/EC.

DESIGN

Population-based cohort study.

SETTING

Sweden.

SAMPLE

A total of 941 841 Swedish women delivering their first child between 1987 and 2008.

METHODS

Data from the Swedish Multigeneration Register were linked to the Swedish Hospital Discharge Register. The risk of PEC/EC was determined in primiparous women with a family history of VTE (in parents and/or siblings), compared with primiparous women without a family history of VTE. Odds ratios (ORs) were calculated by logistic regression.

MAIN OUTCOME MEASURE

PEC/EC in first pregnancy.

RESULTS

In total, 43 621 women had PEC/EC in association with their first pregnancy. The OR for PEC/EC in women with a family history of VTE was 1.06 (95% CI 1.01-1.11); however, a family history of VTE was associated with higher odds of PEC/EC among women with previous hypertension (OR 1.38, 95% CI 1.25-1.52).

CONCLUSION

A family history of VTE is weakly associated with PEC/EC risk, and is not clinically useful for the prediction of PEC/EC. The results of the present study suggest that it is unlikely that strong disease-causing mutations shared by VTE and PEC/EC are common in the Swedish population. The novel association between family history and PEC/EC among the subgroup with previous hypertension needs further confirmation in future studies.

Pregnancy after catheter-directed thrombolysis for acute iliofemoral deep venous thrombosis

Objective:

To assess the safety and efficacy of low-molecular-weight heparin (LMWH) in pregnancy and puerperium in women with previous acute iliofemoral deep venous thrombosis (DVT) treated with catheter-directed thrombolysis (CDT).

Materials and methods:

Consecutive patients treated for acute iliofemoral DVT using CDT between June 1999 and June 2009 were followed yearly by colour duplex ultrasound scanning. A subgroup of these patients who became pregnant during the follow-up period, three months to 10 years after CDT, was included in the present study. During pregnancy, thromboprophylaxis using LMWH was prescribed according to individual risk assessment, and the women were regularly assessed for adverse events. Women on warfarin had this treatment discontinued before the sixth week of pregnancy in order to prevent potential teratogenic adverse effects. Administration of LMWH was started at international normalized ratio ≤<2.0, and continued during pregnancy, delivery and puerperium. Postnatal, the anticoagulation treatment was converted back to warfarin and LMWH discontinued after a bridging period. Women, who, prior to pregnancy, had discontinued anticoagulation treatment after CDT, were prescribed anticoagulation treatment using LMWH as early in pregnancy as practical. LMWH was continued during pregnancy, delivery and for six weeks postpartum. All women were prescribed graduated compression stockings.

Results:

A total of 33 women completed 45 pregnancies, 44 singletons and 1 gemelli. In 24 (53%) of the cases, the mother had been treated with adjunctive stenting immediately following the CDT. In nine (21%) of the pregnancies, the mother had been on long-time anticoagulation treatment using warfarin prior to conception due to permanent severe risk factors. Thrombophilia was demonstrated in 31 (69%) of the pregnancies, and in 29 (64%) of the patients, the previous DVT was oestrogen-related. Thromboprophylaxis using tinzaparin was given in 41 (91%) and using dalteparin in four (9%) of the pregnancies. Doses of LMWH during pregnancy were adjusted according to risk assessment. One pregnancy was terminated by induced delivery at week 22 due to fetal malformations, and two of the pregnancies (4%) were complicated by intrauterine fetal death, one in week 39 due to severe fetal infection and one in week 23 due to intrauterine fetal growth restriction caused by severe antiphospholipid syndrome. All but one of the pregnancies was carried out without recurrence of DVT or maternal pulmonary embolism and the mother remained having patent deep veins postnatal. The mother with the antiphospholipid syndrome had a recurrent DVT complicated by iliac stent occlusion. This mother was prior to pregnancy on long-time treatment using warfarin. During pregnancy, she was erroneously treated with LMWH in standard prophylaxis doses instead of therapeutic doses and without adding aspirin.

Conclusions:

After CDT for acute iliofemoral DVT including adjunctive stenting, pregnancy can be carried out almost uneventful even in women at high risk of thromboembolism. Thromboprophylaxis during pregnancy using LMWH in a dosage adjusted to individual risk assessment, is essential.

Polymorphisms in antithrombin and in tissue factor pathway inhibitor genes are associated with recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a multifactorial condition. The effect of antithrombin (SERPINC1), protein C (PROC), thrombomodulin (THBD) and tissue factor pathway inhibitor (TFPI) single nucleotide polymorphisms (SNPs) on the risk of RPL is thus far unknown. Our objective was to determine the association of SNPs in the above mentioned genes with RPL. We included 117 non-pregnant women with three or more consecutive losses prior to 20 weeks of pregnancy without a previous history of carrying a fetus to viability, and 264 healthy fertile non-pregnant women who had at least two term deliveries and no known pregnancy losses. The PROC (rs1799809 and rs1799808), SERPINC1 (rs2227589), THBD (rs1042579) and TFPI (rs10931292, rs8176592 and rs10153820) SNPs were analysed by Real Time PCR. Genotype frequencies for PROC 2418A>G, PROC 2405C>T, THBD 1418C>T, TFPI (T-33C and TFPI C-399T) SNPs were similar in cases and controls. The carriers of SERPINC1 786A allele (GA + AA genotypes) had an increased risk for RPL (odds ratio [OR]: 1.77, 95% confidence interval [CI]: 1.05-3.00, p= 0.034) while women carrying the TFPI -287C allele (TC + CC genotypes) had a protection effect on having RPL (OR: 0.46, 95% CI: 0.26-0.83, p= 0.009). The TCC haplotype for TFPI T-33C/ TFPI T-287C/ TFPI C-399T SNPs was less frequent in cases (5.7%) than in controls (11.6%) (OR: 0.45, 95% CI: 0.23-0.90, p= 0.025). In conclusion, our data indicate that SERPINC1 786G>A variant increases the risk for RPL, while TFPI T-287C variant is protective; however, further studies are required to confirm our findings.

Pathogenesis of preeclampsia: the genetic component

Preeclampsia (PE) is one of the main causes of maternal and fetal morbidity and mortality in the world, causing nearly 40% of births delivered before 35 weeks of gestation. PE begins with inadequate trophoblast invasion early in pregnancy, which produces an increase in oxidative stress contributing to the development of systemic endothelial dysfunction in the later phases of the disease, leading to the characteristic clinical manifestation of PE. Numerous methods have been used to predict the onset of PE with different degrees of efficiency. These methods have used fetal/placental and maternal markers in different stages of pregnancy. From an epidemiological point of view, many studies have shown that PE is a disease with a strong familiar predisposition, which also varies according to geographical, socioeconomic, and racial features, and this information can be used in the prediction process. Large amounts of research have shown a genetic association with a multifactorial polygenic inheritance in the development of this disease. Many biological candidate genes and polymorphisms have been examined in their relation with PE. We will discuss the most important of them, grouped by the different pathogenic mechanisms involved in PE.