Thromboembolism in pregnancy

Diagnostic imaging to investigate pulmonary embolism in pregnancy using CT-Pulmonary angiography versus perfusion scan

Background:

Pulmonary embolism (PE) is one of the major causes of maternal mortality; however, its diagnosis based on clinical presentation is a significant challenge; therefore, imaging is required. This study aims to determine the nondiagnostic rate of PE in pregnant women who initially undergone computed tomographic pulmonary angiography (CTPA) or perfusion scan.

Materials and Methods:

In this cross-sectional study, all pregnant or 6-week postpartum women with clinical suspicion of PE were evaluated and underwent CTPA or perfusion scan between March 2017 and June 2019. The nondiagnostic rate of each method was defined as the outcome of this study.

Results:

One hundred and eighty-two women with a clinical suspicion of PE were included, among which the initial imaging method was CTPA in 122 (67.03%) and perfusion scan in 60 (32.97%) women. The nondiagnostic imaging for CTPA was significantly lower than the perfusion scan (9 cases (7.4%) versus 25 cases (41.7%), respectively). Logistic regression assessment revealed a statistical outcome by controlling the confounders including gestational trimester at diagnosis, hypertension, ejection fraction, and tachycardia (odds ratio 15.911, 95% confidence interval: 5.177–48.897, P < 0.001).

Conclusion:

Based on the current study, CTPA is superior to perfusion scans to diagnose PE among pregnant or postpartum women with normal chest X-ray suspicion for PE.

Imaging for the exclusion of pulmonary embolism in pregnancy

BACKGROUND

Pulmonary embolism is a leading cause of pregnancy-related death. An accurate diagnosis in pregnant patients is crucial to prevent untreated pulmonary embolism as well as unnecessary anticoagulant treatment and future preventive measures. Applied imaging techniques might perform differently in these younger patients with less comorbidity and altered physiology, who largely have been excluded from diagnostic studies.

OBJECTIVES

To determine the diagnostic accuracy of computed tomography pulmonary angiography (CTPA), lung scintigraphy and magnetic resonance angiography (MRA) for the diagnosis of pulmonary embolism during pregnancy.

SEARCH METHODS

We searched MEDLINE and Embase until July 2015. We used included studies as seeds in citations searches and in 'find similar' functions and searched reference lists. We approached experts in the field to help us identify non-indexed studies.

SELECTION CRITERIA

We included consecutive series of pregnant patients suspected of pulmonary embolism who had undergone one of the index tests (computed tomography (CT) pulmonary angiography, lung scintigraphy or MRA) and clinical follow-up or pulmonary angiography as a reference test.

DATA COLLECTION AND ANALYSIS

Two review authors performed data extraction and quality assessment. We contacted investigators of potentially eligible studies to obtain missing information. In the primary analysis, we regarded inconclusive index test results as a negative reference test, and treatment for pulmonary embolism after an inconclusive index test as a positive reference test.

MAIN RESULTS

We included 11 studies (four CTPA, five lung scintigraphy, two both) with a total of 695 CTPA and 665 lung scintigraphy results. Lung scintigraphy was applied by different techniques. No MRA studies matched our inclusion criteria.Overall, risk of bias and concerns regarding applicability were high in all studies as judged in light of the review research question, as was heterogeneity in study methods. We did not undertake meta-analysis. All studies used clinical follow-up as a reference standard, none in a manner that enabled reliable identification of false positives. Sensitivity and negative predictive value were therefore the only valid test accuracy measures.The median negative predictive value for CTPA was 100% (range 96% to 100%). Median sensitivity was 83% (range 0% to 100%).The median negative predictive value for lung scintigraphy was 100% (range 99% to 100%). Median sensitivity was 100% (range 0% to 100%).The median frequency of inconclusive results was 5.9% (range 0.9% to 36%) for CTPA and 4.0% (range 0% to 23%) for lung scintigraphy. The overall median prevalence of pulmonary embolism was 3.3% (range 0.0% to 8.7%).

AUTHORS' CONCLUSIONS

Both CTPA and lung scintigraphy seem appropriate for exclusion of pulmonary embolism during pregnancy. However, the quality of the evidence mandates cautious adoption of this conclusion. Important limitations included poor reference standards, necessary assumptions in the analysis regarding inconclusive test results and the inherent inability of included studies to identify false positives. It is unclear which test has the highest accuracy. There is a need for direct comparisons between diagnostic methods, including MR, in prospective randomized diagnostic studies.

Incidence of pulmonary and venous thromboembolism in pregnancies after in vitro fertilisation: cross sectional study

OBJECTIVE

To estimate the risk of pulmonary embolism and venous thromboembolism in pregnant women after in vitro fertilisation.

DESIGN

Cross sectional study.

SETTING

Sweden.

PARTICIPANTS

23,498 women who had given birth after in vitro fertilisation between 1990 and 2008 and 116,960 individually matched women with natural pregnancies.

MAIN OUTCOME MEASURES

Risk of pulmonary embolism and venous thromboembolism (identified by linkage to the Swedish national patient register) during the whole pregnancy and by trimester.

RESULTS

Venous thromboembolism occurred in 4.2/1000 women (n=99) after in vitro fertilisation compared with 2.5/1000 (n=291) in women with natural pregnancies (hazard ratio 1.77, 95% confidence interval 1.41 to 2.23). The risk of venous thromboembolism was increased during the whole pregnancy (P<0.001) and differed between the trimesters (P=0.002). The risk was particularly increased during the first trimester, at 1.5/1000 after in vitro fertilisation versus 0.3/1000 (hazard ratio 4.22, 2.46 to 7.26). The proportion of women experiencing pulmonary embolism during the first trimester was 3.0/10,000 after in vitro fertilisation versus 0.4/10,000 (hazard ratio 6.97, 2.21 to 21.96).

CONCLUSIONS

In vitro fertilisation is associated with an increased risk of pulmonary embolism and venous thromboembolism during the first trimester. The risk of pulmonary embolism is low in absolute terms but because the condition is a leading cause of maternal mortality and clinical suspicion is critical for diagnosis, an awareness of this risk is important.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01524393.

Use of imaging for investigation of suspected pulmonary embolism during pregnancy and the postpartum period

Pulmonary embolism (PE) is recognized as a leading cause of maternal mortality in the developed world; however, it is a very difficult diagnosis to make on clinical grounds, and in most cases imaging is required. Pregnancy is a recognized risk factor for venous thromboembolism, and symptoms of normal pregnancy including shortness of breath, tachycardia and leg swelling are included in clinical tools for risk stratification for PE in the non-pregnant population. This results in a very low threshold for imaging, despite concerns regarding the risk of exposure to ionizing radiation both for the fetus and the maternal breast. We reviewed the results of all ventilation/perfusion scans and computed tomography pulmonary angiograms performed in pregnant women at a single institution to identify how many of these tests were positive for PE, and which clinical features may identify a low-risk group. A total of 386 scans were performed to investigate 375 episodes of suspected PE, representing 1.3-1.5% of pregnant women. Fifteen patients were diagnosed with PE, giving an incidence of one in 2000 maternities. The only statistically significant factors associated with PE were smoking or the presence of multiple risk factors. Clinical features of tachycardia and leg swelling did not provide significant diagnostic value; however, the absence of pleuritic chest pain had a negative predictive value of 97.8%. Arterial blood gas and D-dimer were statistically different between those with and without PE but not to a clinically useful degree. Currently available clinical and laboratory tools are not adequate to exclude a diagnosis of PE in a pregnant patient, thus imaging is justified to exclude PE. Further longitudinal studies to identify a low-risk group who do not require imaging is vital.

Combined cilioretinal artery and partial central retinal vein occlusion in the postpartum period

PURPOSE

To report a combined cilioretinal artery and partial central retinal vein occlusion shortly after delivery in a twin-pregnant woman.

METHODS

A 25-year-old woman presented to our clinic with the complaint of blurred vision in the right eye 1 week after delivery. She underwent detailed ophthalmic and systemic investigations.

RESULTS

The patient had an uncomplicated twin pregnancy. Ocular examination showed combined cilioretinal artery and partial central retinal vein occlusion in the right eye. Systemic diseases were excluded. Laboratory evaluations revealed increased plasma d-dimer level (1.64 mg/mL). Spontaneous recovery occurred without treatment 1 month after delivery.

CONCLUSION

Twin pregnancy may lead to exaggerated hypercoagulability and increased d-dimer level in pregnant women. This situation may be a risk factor for retinochoroidal vascular occlusions.

Treatment options in massive pulmonary embolism during pregnancy; a case-report and review of literature

Systemic thrombolysis with recombinant tissue plasminogen activator (rt-PA), streptokinase or urokinase is considered as high-risk treatment in pregnancy. However, several reports have described the successful use of systemic thrombolysis in pregnant patients with massive pulmonary embolism and haemodynamic instability.

CASE

We describe a 34-year old, pregnant female, who presented at 25 weeks of gestation with an acute collapse with reduced consciousness and shortness of breath caused by massive pulmonary embolism. Because of significant haemodynamic instability, increased right ventricular pressure and no improvement after intravenous heparin, thrombolytic therapy was administered. The response to thrombolytic therapy was excellent. No severe haemorrhagic complications were observed. Anticoagulant therapy with LMWH was continued until delivery. A healthy child was born at term.

REVIEW

In English literature, 13 patients received thrombolysis during pregnancy because of pulmonary embolism. No maternal deaths, four non-fatal maternal major bleeding complications, 30.8%;95%CI(9.1-61.4), two fetal deaths, 15.4%;95%CI(1.9-45.5), and five preterm deliveries, 38.5%;95%CI(13.9-68.4), were observed. Surgical embolectomy and catheter embolectomy or catheter thrombolysis has only been performed in 12 patients.

CONCLUSION

The number of reports on thrombolytic therapy, surgical embolectomy and catheter embolectomy or thrombolysis for massive pulmonary embolism during pregnancy are limited. We suggest an international registry for pregnant patients undergoing thrombolysis or embolectomy to gain more information about these treatment options. Nevertheless, complication rates of thrombolytic therapy are acceptable in the light of the underlying disease, and in the meantime, current data do not justify withholding pregnant women from thrombolytic therapy in case of life-threatening PE.

Venothromboembolism

This article focuses on the clinical presentation, diagnosis, and management of veno-thromboembolism, including deep venous thrombosis (DVT) and pulmonary embolism (PE), from the perspective of the emergency physician. The discussion is divided into two sections: DVT and PE. Because veno-thromboembolism is a continuum, certain aspects, such as background, incidence, the use of D dimer, and anticoagulation of both DVT and PE, are discussed together. Heavier emphasis is placed on topics germane to the emergency physician, and considerations for special populations are reviewed.