Diagnosis and management of iliac vein thrombosis in pregnancy resulting from May-Thurner Syndrome

May-Thurner Syndrome in a Case of Left Iliofemoral Vein Thrombosis With Contralateral Tubo-Ovarian Abscess in the Post-postpartum Period

May-Thurner syndrome (MTS) is a rare, yet important, differential diagnosis in reproductive-age women with deep vein thrombosis (DVT). It is characterized by the compression of the left common iliac vein by the right common artery against the lumbar vertebra. The condition is complicated by recurrent DVT with pulmonary thromboembolism (PTE). Here is a case of multiparous women in early puerperium with right tubo-ovarian abscess and left lower limb DVT likely due to MTS. The diagnosis was further complicated by the presence of persistent thrombocytosis but a myeloproliferative neoplasm was ruled out by genetic mutation testing. She was given anticoagulants, and laparotomy was done for the excision of the tubo-ovarian mass in view of the persistent fever not responding to injectable antibiotics. PTE in the postoperative period was managed by anticoagulants followed by an inferior vena cava (IVC) filter for the risk of recurrent DVT and/or PTE in an MTS case.

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.

Peripartum management of deep venous thrombosis in the context of antithrombin deficiency and May-Thurner syndrome

Literature regarding the management of thrombus refractory to first-line treatment in the setting of pregnancy is limited, and management is made even more complicated in the context of thrombophilia. This case reviews the management of a patient with antithrombin deficiency who developed a massive thrombus during pregnancy, which was complicated by May-Thurner syndrome, lack of improvement with heparin, and preterm labor. The patient received multidisciplinary care throughout the pregnancy. At 35 weeks, anticoagulation was paused as she underwent induction of labor and delivery followed by postpartum placement of inferior vena cava filter and restarting heparin. Successful management of our pregnant patient with thrombus refractory to heparin hinged on individualized treatment for medical optimization with anticoagulation and antithrombin concentrate prior to labor followed by immediate postpartum placement of inferior vena cava filter.

Management of May Thurner Syndrome in Pregnant Patients

May Thurner Syndrome contributes to thromboembolic disease and can cause significant morbidity in pregnant patients secondary to exaggerated anatomic relationships and physiologic changes in the hematologic system favoring thrombogenesis. Because this condition is both underrecognized and underreported, management in pregnant and postpartum patients is based on expert opinion without any formal evidence-based guidance. Herein, we review five pregnancies in four patients with May Thurner Syndrome and general management strategies. Through collaborative and multidisciplinary care, patients with May Thurner Syndrome can be safely and successfully managed during pregnancy and the postpartum period with appropriate anticoagulation.

Inferior vena cava filters in pregnancy: Safe or sorry?

Background

Potential hazards of vena cava filters include migration, tilt, perforation, fracture, and in-filter thrombosis. Due to physiological changes during pregnancy, the incidence of these complications might be different in pregnant women.

Aim

To evaluate the use and safety of inferior vena cava filters in both women who had an inferior vena cava filter inserted during pregnancy, and in women who became pregnant with an inferior vena cava filter in situ.

Methods

We performed two searches in the literature using the keywords “vena cava filter”, “pregnancy” and “obstetrics”.

Results

The literature search on women who had a filter inserted during pregnancy yielded 11 articles compiling data on 199 women. At least one filter complication was reported in 33/177 (19%) women and included in-filter thrombosis (n = 14), tilt (n = 6), migration (n = 5), perforation (n = 2), fracture (n = 3), misplacement (n = 1), air embolism (n = 1) and allergic reaction (n = 1). Two (1%) filter complications led to maternal deaths, of which at least one was directly associated with a filter insertion. Filter retrieval failed in 9/149 (6%) women. The search on women who became pregnant with a filter in situ resulted in data on 21 pregnancies in 14 women, of which one (6%) was complicated by uterine trauma, intraperitoneal hemorrhage and fetal death caused by perforation of the inferior vena cava filter.

Conclusion

The risks of filter complications in pregnancy are comparable to the nonpregnant population, but could lead to fetal or maternal death. Therefore, only in limited situations such as extensive thrombosis with a contraindication for anticoagulants, inferior vena filters should be considered in pregnant women.

Combined high-resolution 3D CUBE T1-weighted imaging and non-contrast-enhanced magnetic resonance venography for evaluation of vein stenosis in May-Thurner syndrome

PURPOSE

To explore the feasibility of high-resolution MRI 3-dimensional (3D) CUBE T1-weighted magnetic resonance imaging (MRI) in combination with non-contrast-enhanced (NCE) magnetic resonance venography (MRV) for the assessment of lumen stenosis in May-Thurner syndrome.

METHODS

Twenty-nine patients underwent computed tomography venography (CTV) and high-resolution MRI-CUBE T1, and NCE MRV acquisitions. ANOVA and LSD tests were used to compare the stenosis rate and narrowest and distal diameters of the vessel lumen.

RESULTS

There were no significant differences in the estimated stenosis rate between CTV, CUBE T1, and NCE MRV (p = 0.768). However, there were significant differences in the measured stenosis diameters of the left common iliac vein (LCIV), with CTV giving the largest mean diameter and CUBE had the smallest mean diameter (p < 0.05). The measured normal LCIV diameters did not significantly differ between MRV and CUBE (p = 0.075) but were significantly larger on CTV than on MRV and CUBE (p < 0.05).

CONCLUSIONS

Compared with CTV, a combination of CUBE and MRV could provide an improved assessment of the degree of lumen stenosis in May-Thurner syndrome and demonstrate acute thrombosis. MRI underestimates the diameter of the vessel in comparison with CTV. MRI can be a substitute tool for Duplex ultrasound and CTV.

Common iliac vein stenting for May-Thurner syndrome and subsequent pregnancy

BACKGROUND

For women with left common iliac vein compression (ie, May-Thurner syndrome) who undergo venous stenting and subsequently become pregnant, concerns have been raised regarding a possible compromise of stent patency due to compression from the gravid uterus and the hypercoagulability induced by pregnancy. Only a small body of literature exists on this subject, and limited management guidelines are available. The present study was designed to evaluate the safety of iliac vein stenting for May-Thurner syndrome (MTS) with subsequent pregnancy.

METHODS

Female patients who had undergone common iliac vein stenting at our center who were aged 18 to 45 years and had subsequently become pregnant were identified. A retrospective medical record review of eight eligible patients was conducted, recording the demographics, procedural characteristics, and anticoagulation strategies. The primary outcome evaluated was stent patency.

RESULTS

All eight patients had undergone left common iliac vein stenting for MTS. A total of eight stents were placed, and all demonstrated duplex ultrasound patency throughout pregnancy and postpartum. Seven patients delivered healthy pregnancies, and one experienced a stillbirth. The clinical CEAP (clinical, etiologic, anatomic, pathophysiologic) class remained unchanged or improved from pregnancy to postpartum for all patients. The average age at stent placement was 31 ± 5 years, and the average interval from stent placement to pregnancy was 28 ± 19 months. One patient developed nonobstructive deep vein thrombosis (DVT) of the left femoral vein during pregnancy and was treated with therapeutic enoxaparin. The nonobstructive DVT did not compromise the iliac vein stent. Two patients received low-dose aspirin and prophylactic doses of enoxaparin, one for a history of DVT and factor V Leiden and one for a recent history of fertility treatment. The five remaining patients received no anticoagulation, three received low-dose aspirin, and two received no antiplatelet therapy.

CONCLUSIONS

Common iliac vein stent patency was not compromised by subsequent pregnancy in our eight patients with MTS. Furthermore, the stents remained patent throughout pregnancy in patients receiving a wide range of anticoagulation and antiplatelet treatments, suggesting that no uniform therapeutic threshold exists and treatment should be individualized. For most patients, low-dose aspirin alone or no treatment was adequate. This could have implications for counseling women who require intervention for MTS and are of child-bearing age.

Left common iliac vein compression identified by vascular ultrasonography in asymptomatic women: does standing position influence diagnosis?

Background

Vascular ultrasonography is the imaging exam of choice for initial screening for left common iliac vein compression, which is an asymptomatic finding that can be detected in up to 25% of some patient samples.

Objective

To determine, using vascular ultrasonography, whether findings of left common iliac vein compression in asymptomatic women are different when assessed in the prone and standing positions.

Methods

This is a cross-sectional observational study of 50 adult female volunteers with no symptoms of pelvic venous compression. The parameters assessed with vascular ultrasonography in the prone and standing positions were diameters and maximum velocities of the left common iliac vein at the point at which it crosses behind the right common iliac artery and before this point, in addition to left common iliac vein velocity indices at the crossing.

Results

Eight cases of significant compression of the left common iliac vein were identified when assessed in prone position (16%) and just two cases (4%) were identified in the standing position. Left common iliac vein diameters were statistically larger (p = 0.002) at the point where it crosses behind the right common iliac artery in the standing position and velocities and velocity indices were statistically higher (p < 0.001) in the prone position. No significant compression of the left common iliac vein was identified in the standing position when velocity indices were normal in the prone position.

Conclusions

There was no difference in detection of significant compression of the left common iliac vein when assessed in the standing position in comparison with assessment in the prone position. However, the study showed that anatomic compression of the left common iliac vein may be reduced in the standing position.

May-Thurner Syndrome Is Aggravated by Pregnancy

This study aims to emphasize that asymptomatic patients with undiagnosed and asymptomatic May-Thurner syndrome (MTS) may firstly develop severe compression during pregnancy. A 40-year-old woman, G1P0, at 22 weeks of twin gestation presented with left lower extremity edema and pain. One twin was structurally normal while the other had bilateral renal agenesis with oligohydramnios. Magnetic resonance venography (MRV) revealed severe compression of the left iliac vein by the right iliac artery without evidence of deep vein thrombosis (DVT). Conservative treatment with anticoagulant prophylaxis was instituted throughout the rest of pregnancy and postpartum period. She was also complicated with severe pre-eclampsia, a cesarean section was performed due to a prolapsed cord at 27 weeks of gestation, and she gave birth to a surviving baby weighing 1100 g. In conclusion, this case report provides evidence that pregnancy can disclose a subtle May-Thurner anatomy to be symptomatic without DVT. Successful pregnancy outcomes could be achieved with conservative treatment and anticoagulant prophylaxis.

May-Thurner syndrome: History of understanding and need for defining population prevalence

Patients with May-Thurner syndrome (MTS) are at elevated risk of developing an extensive left iliofemoral deep vein thrombosis (DVT; localized blood clot) due to an anatomical variant where the right common iliac artery compresses the left common iliac vein against the lumbar spine. While MTS was initially presumed to be rare when it was first anatomically defined in 1957, case reports of this syndrome have recently become more frequent, perhaps due to improved imaging techniques allowing for enhanced visualization of the iliac veins. Still, the population burden of this condition is unknown, and there is speculation it may be higher than generally perceived. In the present review, we (a) review history of how MTS became recognized, (b) describe practical challenges of studying MTS in population-based settings due to the specialized imaging required for diagnosis, (c) discuss why the contribution of MTS to DVT may be underestimated, (d) describe uncertainty regarding the degree of venous compression which leads to DVT, and (e) outline future research needs. Our goal is to raise awareness of MTS and spark additional research into the epidemiology of this condition, which may be an underappreciated causative venous thromboembolism risk factor.

May-Thurner syndrome - Are we aware enough?

Iliac vein compression syndrome (May-Thurner syndrome - MTS) is an anatomically variable clinical condition in which the left common iliac vein is compressed between the right common iliac artery and the underlying spine. This anatomic variant results in an increased incidence of left iliac or iliofemoral vein thrombosis. It predominantly affects young women in the second or third decades of life with preponderance during pregnancy or oral contraceptive use. Although MTS is rare, its true prevalence is underestimated but it can be a life-threatening condition due to development of pulmonary embolism (PE). In this case based review the authors present three cases of MTS. All patients had been previously confirmed with PE, but despite they were admitted to hospital, diagnosed and correctly treated for PE and investigated for thrombophilia, the iliac vein compression syndrome was not suspected or investigated. With this presentation the authors would like to emphasize that MTS is mostly underdiagnosed, and it needs to be ruled out in left iliofemoral vein thrombosis in young individuals.

Thrombolysis for Venous Thromboembolism During Pregnancy: A Literature Review

BACKGROUND

Pregnancy is a hypercoagulable state, conferring an increased risk of venous thromboembolism (VTE). However, treatment algorithms for deep venous thrombosis and pulmonary embolism are based on studies of nonpregnant patients.

METHODS

A literature review of cases in which thrombolysis was used for the treatment of VTE during pregnancy was conducted using the PubMed (National Institutes of Health) database.

RESULTS

A PubMed database search of English language articles for reports of thrombolysis for the treatment of VTE in pregnancy identified 215 cases, including 183 cases of systemic thrombolysis, 19 cases of catheter-directed thrombolysis, and 13 cases of mechanical thrombectomy. For systemic thrombolysis, the maternal complication rate was 4.40% and the fetal complication rate was 1.65%. For catheter-directed thrombolysis, the maternal complication rate was 14.75% and the fetal complication rate was 5.2%. In cases of mechanical thrombectomy, there were no reported maternal or fetal complications.

CONCLUSIONS

Although conservative strategies are preferred in pregnancy, thrombolysis is an adjunct for limb or life-threatening VTE. Review of past reports suggests low rates of maternal and fetal complications following systemic thrombolysis and mechanical thrombectomy but higher rates of complications after catheter-directed thrombolysis in the treatment of VTE during pregnancy.

Retrievable inferior vena cava filter utilization in obstetric patients

Objectives: The objective of this study is to evaluate patterns of use and outcomes of retrievable inferior vena cava filters (rIVCF) in obstetric patients. Methods: A single center review of consecutive patients who underwent rIVCF placement during pregnancy/postpartum in 2005-2016. A pooled analysis of the relevant cases in the English literature was conducted. Results: The current cohort comprised 24 women, median age 27 [interquartile range 24-30] years. Among 10 filters placed during pregnancy, the most common indication (n = 4) was the need to withhold anticoagulation therapy before delivery, in the presence of acute thrombosis. In the postpartum period, most filters (64%, 9/14) were an adjunct to catheter-directed thrombolytic therapy. Inferior vena cava filters (IVCF)-related complications occurred in seven (29.2%). Retrieval was attempted in 21 patients (87.5%), and was technically successful in 19 (90.5%), for an overall removal rate of 79.1%. Pooled analysis of the literature (n = 98) showed comparable rates for filter removal and complications (81.6%, p = .78 and 24.2%, p = .60, respectively). Suprarenal placement (p = .12) and elective cesarean section (p = .19) did not reduce overall complication and retrieval rates. The estimated radiation dose among pregnant patients who underwent rIVCF placement without adjunct catheter directed thrombolysis (CDT) (mean 695 Gy cm²) was significantly lower than the radiation dose used in postpartum patients (1863 Gy cm²) or in pregnant patients in whom adjunct CDT was utilized (4059 Gy cm²) (p = .001 for both comparisons). Conclusions: Frequent rIVCF-related complications, radiation exposure, and removal failure call for their cautious utilization in obstetric patients. The role of suprarenal placement and elective cesarean section to improve outcomes has yet to be established.

Minimally Invasive Management of Ovarian Cysts During Pregnancy Using Ethanol Sclerosis

Traditionally, the management of symptomatic ovarian cysts in pregnancy has been limited to laparoscopy or laparotomy with the associated morbidity. However, in select patients requiring intervention, the risks of surgery may be minimized with sclerotherapy. We present the first case report, to our knowledge, of ethanol sclerosis of an ovarian cyst during pregnancy. A description of the surgical technique to complete such a procedure is provided as well as a brief review of the current literature with respect to the use of sclerotherapy for the management of ovarian cysts.

Anticoagulant Therapy in a Pregnant Woman with May-Thurner Syndrome

A 39-year-old woman with a 9-week abdominal pregnancy noted pain in her lower abdomen and left leg. Since successive thrombi were observed extending from the left common iliac vein to the popliteal vein along with a thrombus in the left pulmonary artery, we diagnosed her with pulmonary thromboembolism with deep venous thrombosis (DVT). May-Thurner syndrome may have contributed to DVT in the left leg when the left iliac vein was compressed by the right iliac artery. She underwent anticoagulant therapy with heparin, followed by the subcutaneous injection of heparin at home after discharge. We herein report the case of a pregnant woman with May-Thurner syndrome who safely gave birth.

Nonclinical aspects of venous thrombosis in pregnancy

Pregnancy is a hypercoagulable state which carries an excess risk of maternal venous thrombosis. Endothelial injury, alterations in blood flow and activation of the coagulation pathway are proposed to contribute to the hypercoagulability. The risk for thrombosis may be accentuated by certain drugs and device implants that directly or indirectly affect the coagulation pathway. To help ensure that these interventions do not result in adverse maternal or fetal outcomes during pregnancy, gravid experimental animals can be exposed to such treatments at various stages of gestation and over a dosage range that would identify hazards and inform risk assessment. Circulating soluble biomarkers can also be evaluated for enhancing the assessment of any increased risk of venous thrombosis during pregnancy. In addition to traditional in vivo animal testing, efforts are under way to incorporate reliable non-animal methods in the assessment of embryofetal toxicity and thrombogenic effects. This review summarizes hemostatic balance during pregnancy in animal species, embryofetal development, biomarkers of venous thrombosis, and alterations caused by drug-induced venous thrombosis.