Guidance for the diagnosis of pulmonary embolism during pregnancy: Consensus and controversies

Pregnancy-Related Thromboembolism-Current Challenges at the Emergency Department

Thrombotic events during pregnancy are burdened by an increased risk of morbidity and mortality, despite innovations in their diagnosis and treatment. Given their multifactorial etiology, it is important to understand all the pathophysiological mechanisms but especially to achieve correct and timely diagnosis. Pulmonary embolism (PE) during pregnancy represents a rare event, with an incidence of 1 per 1000 pregnancies, but it is also one of the leading causes of death during pregnancy. Managing PE in the acute setting is even more challenging and complex due to the attempt to maintain a balance between hemorrhagic and thrombotic complications while ensuring an optimal outcome for both the mother and the baby. In this review, our aim is to analyze the most significant challenges of acute PE during pregnancy and identify suitable management approaches for specific situations in order to improve the prognosis of pregnant women.

Pulmonary Embolism in Pregnancy: A Review for Clinical Practitioners

Diagnostic and therapeutic decision-making in pregnancy with suspected pulmonary embolism (PE) is challenging. European and other international professional societies have proposed various recommendations that are ambiguous, probably due to the unavailability of randomized controlled trials. In the following sections, we discuss the supporting diagnostic steps and treatments. We suggest a standardized diagnostic work-up in pregnant patients presenting with symptoms of PE to make evidence-based diagnostic and therapeutic decisions. We strongly recommend that clinical decisions on treatment in pregnant patients with intermediate- or high-risk pulmonary embolism should include a multidisciplinary team approach involving emergency physicians, pulmonologists, angiologist, cardiologists, thoracic and/or cardiovascular surgeons, radiologists, and obstetricians to choose a tailored management option including an interventional treatment. It is important to be aware of the differences among guidelines and to assess each case individually, considering the specific views of the different specialties. This review summarizes key concepts of the diagnostics and acute management of pregnant women with suspected PE that are supportive for the clinician on duty.

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.

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.

Risk of neonatal hypothyroidism in newborns from mothers exposed to CTPA during pregnancy: Ancillary data from a prospective outcome study

BACKGROUND

Neonatal hypothyroidism is often raised as a potential concern for the use of computed tomography pulmonary angiography (CTPA) in pregnant women with suspected pulmonary embolism (PE).

OBJECTIVES

To assess the incidence of neonatal hypothyroidism among newborns from mothers exposed to CTPA.

PATIENTS/METHODS

Pregnant women with clinically suspected PE were included in a multicenter, multinational prospective diagnostic management outcome study, based on pretest clinical probability assessment, high-sensitivity D-dimer testing, bilateral lower limb venous compression ultrasonography, and CTPA. Results of Guthrie tests were systematically collected for newborns of all women who required CTPA as part of the diagnostic strategy. A thyroid-stimulating hormone (TSH) level above 15 U/ml was used to define hypothyroidism.

RESULTS

Out of the 166 women included in the Swiss participating centers, 149 underwent a CTPA including 14 with twin pregnancies. Eight women suffered a pregnancy loss and results of the Guthrie test could not be retrieved for four newborns. All TSH levels were reported as being below 15 U/ml. The incidence of neonatal hypothyroidism was 0/151 (0.0%, 95% confidence interval: 0.0%-2.5%).

CONCLUSIONS

We did not identify any cases of neonatal hypothyroidism in our cohort of 149 pregnant women investigated for suspected PE using a CTPA. Along with previous literature data, this provides further reassuring data regarding the use of CTPA in this indication.

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.

Diagnostic imaging for suspected pulmonary embolism during pregnancy and postpartum: A comparative radiation dose study

INTRODUCTION

To compare the radiation dose exposure and diagnostic efficiency of computed tomographic pulmonary angiography (CTPA) and ventilation/perfusion imaging (V/Q) for clinically suspected pulmonary embolism (PE) in pregnant and postpartum women in a tertiary hospital setting.

METHODS

A retrospective cohort study of 473 pregnant and postpartum women referred for CTPA or V/Q for clinically suspected PE between January 2013 and December 2018 at a tertiary hospital. Maternal effective radiation dose, breast-absorbed radiation dose and fetal-absorbed dose estimates were calculated. Diagnostic yield was evaluated from radiological findings.

RESULTS

Computed tomographic pulmonary angiography (CTPA) was more commonly used for the imaging of suspected PE in pregnant and postpartum populations (51.9% vs. 48.1% and 77.1% vs. 22.9%, respectively). CTPA was associated with higher maternal effective and breast-absorbed doses (maternal effective CTPA 4.7 (±2.9) mSv (millisievert), V/Q 1.7(±0.8) mSv (mean difference 2.93 mSv P < 0.001), and breast-absorbed CTPA 8.0 (±5.2) mGy (milligray), V/Q 0.3 (±0.1) (mean difference 7.67 mGy P < 0.001), respectively). Fetal radiation dose exposure was low. The incidence of positive PE was 5.5%. Indeterminate rates of CTPA and V/Q were 3.0% and 5.5% (P = 0.176), respectively.

CONCLUSIONS

Compared to V/Q, CTPA is associated with higher maternal and breast radiation dose; however, modern CT scanners achieve lower radiation doses than historically described. Fetal radiation dose was comparably low. The diagnostic yield of the imaging modalities in pregnant and postpartum women is similar. Revision of guidelines should occur with the advances in CT technology.

Pulmonary Embolism and Pregnancy-Challenges in Diagnostic and Therapeutic Decisions in High-Risk Patients

Diagnosis of acute PE in pregnant women with haemodynamic instability is following the general integrated risk-adapted diagnostic algorithm and starts with bedside echocardiography to assess RV function. If RV dysfunction is identified, a prompt and immediate reperfusion without further imaging should be initiated. Although pregnancy is listed as a relative contraindication of systemic thrombolysis, in pregnant women with acute PE and haemodynamic instability thrombolysis must be considered. In those cases, other treatment strategies as surgical embolectomy or catheter-directed low-dose thromboylysis or percutaneous thrombectomy should be taken into consideration as well. A multidisciplinary team with experience of PE management in pregnancy should be consulted to reach consensus on the best treatment approach.

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.

Assessing the clinical probability of pulmonary embolism during pregnancy: The Pregnancy-Adapted Geneva (PAG) score

BACKGROUND

The diagnosis of pulmonary embolism (PE) in pregnant women represents an ongoing challenge. As in the general population, the first step in pregnant women with suspected PE consists of assessing clinical pre-test probability (PTP). However, no dedicated clinical decision rule has been developed in this population.

OBJECTIVE

To propose a new version of the Geneva score adapted to pregnant women with suspected PE.

METHODS

Data from a multicenter, prospective management outcome study including 395 women with suspected PE, in whom PTP was assessed using the Geneva score, were used. We first removed items which were present in none of the patients (cancer, age >65 years). Receiver operating characteristic (ROC) curve analysis was then performed for quantitative variables and the optimal threshold defined. The obtained Pregnancy-Adapted Geneva Score (PAG Score) comprised seven items, including an age 40 years or older and a heart rate >110 beats per minute.

RESULTS

The PAG Score showed a high discriminative power to identify patients with a low, intermediate, or high PTP, associated with increasing prevalence of PE, 2.3%, 11.6%, and 61.5%, respectively. The ROC curves showed an area under the curve of 0.795 for the PAG Score compared to 0.684 for the Geneva score.

CONCLUSION

In pregnant women with suspected PE, the PAG Score shows a high discriminative power to identify patients at low, intermediate, or high PTP. It has the strength of being a fully objective decision rule, is clinically relevant, easy to compute, and should now be tested in a prospective outcome study.

Imaging modalities for confirming pulmonary embolism during pregnancy: results from a multicenter international study

OBJECTIVES

We explored the variations in use of imaging modalities for confirming pulmonary embolism (PE) according to the trimester of pregnancy.

METHODS

We included all pregnant patients with confirmed acute PE from RIETE, a prospective registry of patients with PE (03/2001-02/2020). Imaging modalities included computed tomography pulmonary angiography (CTPA), ventilation-perfusion (V/Q) scan, or presence of signs of acute PE along with imaging-confirmed proximal deep vein thrombosis (pDVT) without pulmonary vascular imaging. We compared the imaging modalities to postpartum patients with PE, and other non-pregnant women with PE.

RESULTS

There were 157 pregnant patients (age: 32.7 ± 0.5), 228 postpartum patients (age: 33.9 ± 0.5), and 23,937 non-pregnant non-postpartum women (age: 69.5 ± 0.1). CTPA was the most common modality for confirming PE, from 55.7% in first trimester to 58.3% in second trimester, and 70.0% in third trimester. From first trimester to third trimester, V/Q scanning was used in 21.3%, 16.7%, and 18.3% of cases, respectively. Confirmed pDVT along with the presence of signs/symptoms of PE was the confirmatory modality for PE in 21.3% of patients in first trimester, 19.4% in second trimester, and 6.7% in third trimester. The proportion of postpartum patients confirmed with CTPA (85.5%) was comparable to that of non-pregnant non-postpartum women (83.2%). From the first trimester of pregnancy to postpartum period, there was a linear increase in the proportion of patients with PE diagnosed with CTPA (p = 0.039).

CONCLUSION

CTPA was the primary modality for confirming PE in all trimesters of pregnancy, although its proportional use was higher in later stages of pregnancy.

KEY POINTS

• Computed tomography pulmonary angiography (CTPA) was the primary modality of diagnosis in all trimesters of pregnancy among patients with confirmed pulmonary embolism, even in the first trimester. • From the first trimester of pregnancy to postpartum period, there was a linear increase in the proportion of patients with pulmonary embolism who were diagnosed based on CTPA. • In the postpartum period, use of CTPA as the modality to confirm pulmonary embolism was comparable to non-pregnant patients.

Thrombolysis in massive and submassive pulmonary embolism during pregnancy and the puerperium: a systematic review

Thrombolysis in high-risk pulmonary embolism (PE) patients is recommended worldwide; however, the evidence for thrombolysis during pregnancy and the immediate puerperium remains unclear. We conducted a systematic review from 1950 to 2019 through PubMed, Ovid/Willey, and Cochrane Library to assess the safety and effectiveness of thrombolysis during pregnancy and the immediate puerperium. Additionally, we characterized the clinical presentation, risk stratification, and diagnostic approach. We have communicated our results according to the PRISMA statement. We collected 141 records and, after critical assessment, included 47 case reports of 54 patients, including 43 and 11 patients during pregnancy and puerperium, respectively. During pregnancy, alteplase was the most frequent systemic thrombolytic agent used (67%), but only nine patients received the approved FDA regimen. With catheter-directed thrombolysis, low-dose thrombolytics and fragmentation were the most common regimens. Major bleeding occurred in 18% of cases, but there was no intracranial bleeding. One maternal death occurred secondary to refractory cardiogenic shock. Fetal mortality was 20%. During the immediate puerperium, nine patients received "off-label" first-, second-, and third-generation thrombolytic regimens, and four cases underwent catheter-directed thrombolysis. We observed nine major bleeding events, seven of which were from the uterine location and none of which were intracranial. In conclusion, overall, these data do not suggest prohibitive risk associated with thrombolysis for PE in pregnancy. Management of massive and high-risk submassive PE in pregnancy should be individualized to each patient. In the data presented, no fatal bleeding or intracranial bleeding was observed. Finally, future efforts should systematically collect and report data on high-risk PE in pregnancy and peripartum patients to improve the evidence-base clinical practice.

Management of high-risk pulmonary embolism in pregnancy

Pregnancy-associated high-risk pulmonary embolism (PE) is among the most frequent causes of maternal mortality in the Western world, by causing hemodynamic instability and circulatory failure through a large thrombotic pulmonary obstruction. The very challenging management of these dramatic situations comprises the need to quickly select a therapy of pulmonary reperfusion or hemodynamic replacement, while taking into account both maternal and fetal risks. In this review, we discuss the role of risk stratification in pregnancy-associated PE and the available evidence to support the use of thrombolysis, catheter-directed thrombectomy/thrombolysis, surgical embolectomy and extracorporeal membrane oxygenation. Despite the lack of comparative studies and solid evidence, most reported cases of high-risk pregnancy-associated PE have been treated with thrombolysis, with high maternal and fetal survivals, and thrombolysis is suggested by guidelines in life-threatening PE. For women in the peripartum and early post-partum period, non-fibrinolytic treatments may be preferred as a first-line treatment, if available, because of the particularly high bleeding risk. In all cases, pregnancy-associated high-risk PE requires a multidisciplinary approach involving PE response teams and obstetricians.

Can pregnancy-adapted algorithms avoid diagnostic imaging for pulmonary embolism?

The low prevalence of pulmonary embolism (PE) among pregnant patients presenting with suspected PE implies that most of these patients will be found not have the disease. Given this low prevalence, excluding PE in this population has necessitated the use of sensitive and specific diagnostic imaging, such as computed tomography pulmonary angiography or ventilation-perfusion scanning. Recent studies suggest that a clinical prediction rule with D-dimer testing can also be used to exclude a subset of pregnant patients with suspected PE without the need for diagnostic imaging. The YEARS criteria, which consist of clinical signs and symptoms of deep venous thrombosis, hemoptysis, and PE as the most likely diagnosis (a subjective variable), combined with selective D-dimer levels, seem to safely exclude up to one-third of these patients without imaging. The revised Geneva rule using objective variables, combined with nonpregnancy cutoffs for D-dimer levels, offers some promise, although fewer patients avoided imaging (14%). These recent studies provide evidence in support of radiation avoidance for some patients; however, for most, imaging remains the only option. Future studies should focus on improving the safety and techniques of imaging modalities, in addition to improving the specificity of D-dimer testing and objective prediction rules. Studies assessing patients' and physicians' values, preferences, and risk perceptions are also required to assist clinicians in shared decision making when counseling pregnant patients with suspected PE.

Leg massage during pregnancy with unrecognized deep vein thrombosis could be life threatening: a case report

Background

Traditional massage seems to be safe but not entirely risk free, though serious adverse events are very rare. This report is aimed at illustrating a rare but fatal presentation of massive pulmonary embolism caused by leg massage and also to encourage both massage providers and pregnant women to be aware of undetected or subtle deep vein thrombosis, which could be a life threatening condition as a consequence of leg massage.

Case presentation

A 25-year-old primigravid Thai woman underwent massage at a traditional massage shop at 25th week of gestation. Shortly after leg and foot massage, she had a sudden onset of dyspnea, followed by consciousness alteration, brief spastic-like convulsion, became unconscious and suffered a cardiac arrest. Basic life support (BLS) at the event scene as well as during transfer and advanced cardiovascular life support (ACLS) at the hospital were provided, resulting in successful resuscitation but persistent coma. Bedside echocardiography showed poor contractility of the dilated right ventricle, and pulmonary embolism was suspected. CT angiography (CTA) revealed multiple concentric intraluminal filling defects within the right and left pulmonary arteries, indicating massive pulmonary embolism. The fetus died in utero and spontaneous labor and vaginal delivery occurred.

Conclusion

Leg massage in patients with deep vein thrombosis can dislodge thrombi, leading to life threatening pulmonary embolism, and should be contraindicated. Since pregnant women are at a higher risk of undetected or subtle thromboembolism, traditional massage in pregnant women should be contraindicated unless they are proven to have no such risk.

Investigation and diagnostic imaging of suspected pulmonary embolism during pregnancy and the puerperium: A review of the literature

Pulmonary embolism (PE) is a leading cause of maternal mortality with women at increased risk of PE during pregnancy and the early postpartum period. Clinical assessment of suspected PE during pregnancy is challenging as signs and symptoms associated with PE overlap with physiological changes of pregnancy. Clinical tests and rules commonly used to assess pre-test probability of PE were historically not well validated in the pregnant population. The challenges of clinical assessment in the pregnant and postpartum population result in a lowered threshold for diagnostic imaging. Computed tomographic pulmonary angiography (CTPA) and nuclear medicine lung scintigraphy or ventilation/perfusion (V/Q) scans are the main types of diagnostic imaging for suspected PE. Both methods are associated with small levels of ionising radiation exposure to mother and foetus. Accuracy of the diagnostic imaging tests is paramount. Haemodynamic changes of pregnancy, including increased heart rate, increased blood volume and altered flow velocity in the pulmonary arteries, may influence the quality of imaging. This comprehensive review examines the literature and evidence for the investigation and diagnostic imaging of suspected pulmonary embolism during pregnancy with CTPA and V/Q. Clinical decision-making tools, biomarkers and diagnostic imaging during pregnancy and postpartum will be considered with a focus on diagnostic accuracy and yield, radiation dose exposure (maternal-foetal) and protocol modifications. Current practice guideline recommendations and recent literature on diagnostic pathways are also presented.

Pregnancy-adapted YEARS algorithm: can YEARS do more for pregnant women?

Venous thromboembolism (VTE), as a term that encompasses pulmonary embolism (PE) and deep vein thrombosis (DVT), is one of the leading causes of maternal morbidity and mortality [1], especially in developed countries, where PE takes second place after complications of hypertensive disorders [2]. When compared to non-pregnant women of similar age, pregnant women have an approximately four to five times higher risk of VTE [3], with an incidence of 1 in 1000 pregnancies [4]. Approximately 20–25% of VTE cases are caused by PE and 75–80% of cases are caused by DVT [5]. About 60% of DVT occurs antepartum, with the highest risk of antepartum pregnancy-associated VTE being in the third trimester.However, about 60% of PE occurs postpartum [3].

Pregnancy-adapted YEARS algorithm provides high certainty in ruling out pulmonary embolism and high efficiency in reducing the need for CTPAhttp://bit.ly/2GgH4sv

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.

Comparison of international societal guidelines for the diagnosis of suspected pulmonary embolism during pregnancy

Pregnancy-associated pulmonary embolism is one of the leading causes of maternal mortality. Diagnosis of pulmonary embolism in pregnancy is challenging, with symptoms of pulmonary embolism mimicking those of pregnancy. Several key components such as clinical prediction tools, risk stratification, laboratory tests, and imaging widely used for diagnosis of pulmonary embolism in the non-pregnant population show limitations for diagnosis in pregnancy. Further, because of the difficulty of studying pregnant patients, high-quality research evaluating the performance of these diagnostic components in pregnancy is scarce. Seven international medical society guidelines present clinical diagnostic pathways for evaluation of pulmonary embolism in pregnancy that show conflicting recommendations on the use of these diagnostic components. This Review assesses all key components of diagnostic clinical pathways recommended by guidelines for evaluation of pulmonary embolism in pregnancy, reviews current evidence, compares the guideline recommendations with respect to each key component, and provides our preferred diagnostic pathway. It provides the guidelines and available data needed for informed decision making to diagnose pulmonary embolism in pregnancy.

"You only live twice": multidisciplinary management of catastrophic case in placenta Accreta Spectrum-a case report

Background

Placenta percreta is associated with high hemorrhagic risk and can be complicated with fatal thromboembolic events. Involving a multidisciplinary team in the treatment of these patients is mandatory to reduce morbidity and mortality.

Case presentation

This paper reports the case of a 22-year-old patient with placenta percreta who was referred to our tertiary care center for delivery. Few hours after undergoing a successful cesarean hysterectomy, the patient developed a pulmonary embolism and cardiac arrest. A transthoracic echocardiogram done in the intensive care unit (ICU) showed a thrombus in the right ventricle. After cardiac resuscitation, the patient underwent an urgent thoracotomy and a pulmonary artery thrombectomy; many clots were retrieved from the pulmonary artery. After weaning from extracorporeal circulation, an intraoperative transesophageal cardiac ultrasound enabled the medical team to detect a new free-floating thrombus in the right atrium and right ventricle, and consequently to perform an embolectomy and prevent the patient’s death.

Conclusion

This case emphasizes the role of multidisciplinary team in treating high-risk obstetric cases that could be complicated with massive and fatal thromboembolic events. The use of intraoperative transthoracic echocardiography helps in detecting a new thrombus and guides the anesthesiologist in the intra-operative monitoring.

Outcomes of Multidetector Computed Tomography Pulmonary Angiography in Pregnant and Postpartum Women With Suspected Pulmonary Embolism

PURPOSE

Verify whether there is a difference in likelihood of developing pulmonary embolism (PE) between pregnant women, nonpregnant women of reproductive age, and postpartum (up to 6 weeks) women, by comparing their outcomes on computed tomography pulmonary angiography (CTPA) done for suspicion of PE.

MATERIALS AND METHODS

Retrospective cohort study of 1463 CTPA done for suspicion of PE in females of reproductive age (18-40 years), nonpregnant, pregnant (antepartum), and postpartum, from 2 tertiary-care academic hospitals between October 2006 and September 2015. Primary outcome was diagnosis of PE on imaging. Additional assessment was made of technical adequacy of the studies and method of delivery for the postpartum cohort (vaginal vs caesarean birth). Twenty-nine technically nondiagnostic studies were excluded. The effect of any potential variable on PE status was tested using univariate logistic regression. Subgroup analysis was performed after excluding patients with independent risk factors for PE.

RESULTS

The rate of CTPA positive for PE was less among pregnant patients compared to early postpartum and nonpregnant women of similar age, 2.9% vs 11.5% and 10.3%, respectively. Pregnancy was associated with statistically significant decreased odds ratio of developing a PE on CTPA, 0.23 (0.09-0.89), P value = .004. After excluding patients with additional independent risk factors for PE, there was no statistically significant odds ratio association between presence of PE on CTPA and pregnancy 0.41 (0.13-1.34), P value = .14.

CONCLUSION

Rate of CTPA positive for PE in pregnant women was lower than in nonpregnant and early postpartum women. Pregnancy was statistically significantly less likely to be associated with positive PE on a CTPA study. The common perception that pregnancy (antepartum state) is associated with an increased risk of PE may require a thorough critical reappraisal.

Contemporary best practice in the management of pulmonary embolism during pregnancy

Approximately 1-2 per 1000 pregnancies are complicated by venous thromboembolism (VTE). VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE) and the diagnostic management of pregnancy-related VTE is challenging. Current guidelines vary greatly in their approach to diagnosing PE in pregnancy as they base their recommendations on scarce and weak evidence. The pregnancy-adapted YEARS diagnostic algorithm is well tolerated and is the most efficient diagnostic algorithm for pregnant women with suspected PE, with 39% of women not requiring computed tomographic pulmonary angiography. Low-molecular-weight heparin is the first-choice anticoagulant treatment in pregnancy and should be continued until 6 weeks postpartum and for a minimum of 3 months. Direct oral anticoagulants should be avoided in women who want to breastfeed. Management of delivery needs a multidisciplinary approach in order to decide on an optimal delivery plan. Neuraxial analgesia can be given in most patients, provided time windows since last low-molecular-weight heparin dose are respected. Women with a history of VTE are at risk of recurrence during pregnancy and in the postpartum period. Therefore, in most women with a history of VTE, thromboprophylaxis in subsequent pregnancies is indicated. The reviews of this paper are available via the supplemental material section.

Predictors of radiation dose for CT pulmonary angiography in pregnancy across a multihospital integrated healthcare network

PURPOSE

There is a large range of published effective radiation dose for CTPA during pregnancy. The purpose of our study is to determine the mean effective radiation dose and predictors of mean effective radiation dose for CTPA in pregnant patients across a multihospital integrated healthcare network.

METHODS

This retrospective study evaluates pregnant women who had a CTPA as the first primary advanced imaging test for evaluation of PE in a multihospital integrated healthcare network from January 2012-April 2017. Patient and CT-related data were obtained from the electronic health record and Radimetrics server (Radimetrics Inc, Bayer). DLP was recorded and effective radiation dose in mSv was determined using a conversation factor of 0.014 mSv·mGy^-¹·cm^-¹. Patient size was determined by water equivalent diameter. Bivariate and multivariate analysis were performed for effective radiation dose based on patient and CT factors.

RESULTS

In the 534 CTPA exams, the mean effective radiation dose was 3.96 mSv. Bivariate analysis showed significant differences in radiation dose by trimester, p = 0.042: first trimester 4.52 mSv, second trimester 3.73 mSv, and third trimester 3.95 mSv. Multivariable analysis demonstrated CTPA during first trimester, increasing mAs, kVp, scan length, patient size, and use of mAs modulation, as well as decreasing pitch, to be predictive of higher effective radiation dose.

CONCLUSION

Mean effective radiation dose was on the lower end of published studies. Trimester was a statistically significant predictor of effective radiation dose when accounting for known predictors of radiation dose.

Multimodality cardiovascular imaging in pulmonary embolism

Acute pulmonary embolism (APE) is one of the leading causes of cardiovascular (CV) morbidity and mortality. To select appropriate therapeutic strategy and/or to minimize the mortality and morbidity, rapid and correct identification of life-threatening APE is very important. Also, right ventricular (RV) failure usually precedes acute hemodynamic compromise or death, and thus the identification of RV failure is another important step in risk stratification or treatment of APE. With advances in diagnosis and treatment, the prognosis of APE has been dramatically improving in most cases, but inadequate therapy or recurrent episodes of pulmonary embolism (PE) may result in negative outcomes or, so called, chronic thromboembolic pulmonary hypertension (CTEPH). CTEPH is a condition characterized by remaining chronic thromboembolic material in the pulmonary vasculature and subsequent chronic pulmonary hypertension. Various imaging modalities include chest computed tomography pulmonary angiography (CTPA), echocardiography, magnetic resonance imaging, and nuclear imaging and each are used for the assessment of varying status of PE. Assessment of thromboembolic burden by chest CTPA is the first step in the diagnosis of PE. Hemodynamic assessment can be achieved by echocardiography and also by chest CTPA. Nuclear imaging is useful in discriminating CTEPH from APE. Better perspectives on diagnosis, risk stratification and decision making in PE can be provided by combining multimodality CV imaging. Here, the advantages or pitfalls of each imaging modality in diagnosis, risk stratification, or management of PE will be discussed.

Diagnostic imaging in pregnancy: Making informed decisions

The use of diagnostic imaging involving ionising radiation may be necessary in pregnancy and requires an assessment of the most appropriate and safest imaging modality which will provide the necessary information balanced with the potential risks to the mother and fetus. In most cases, this will involve a potential fetal radiation dose well below 50 mGy. At these doses, there is no risk of lethality, genetic damage/epigenetic change, teratogenicity, growth impairment or sterility. Older epidemiological data indicating a potential increased cancer risk have been contradicted by newer data and better understanding of the biology of low dose radiation. The linear no-threshold rule has been challenged by many and more realistic estimates of oncogenicity risk along with the potential risks of contrast agents are summarised in this review. Imaging in the pregnant population is increasing in both the number of examinations performed and the number of patients being imaged, with the greatest increase being computed tomography scans. Counselling and obtaining informed consent for imaging that involves radiation requires the clinician to communicate with the woman and her family a realistic estimate of the potential radiation dose to herself and her fetus, to describe and quantitate the risks of this estimated dose, to outline the benefits of the imaging procedure and to respond to any questions or concerns. As almost all diagnostic imaging involves doses below the 50 mGy threshold, clinically indicated investigations should not be withheld during pregnancy. All allied staff must also be well informed to ensure the patient receives a consistent message about the risks and benefits of the proposed test.

Could the YEARS algorithm be used to exclude pulmonary embolism during pregnancy? Data from the CT-PE-pregnancy study

INTRODUCTION

The recently proposed YEARS algorithm was shown to safely exclude pulmonary embolism (PE) and reduce the use of computed tomography pulmonary angiography (CTPA) among pregnant women with suspected PE. Our aim was to externally validate this finding.

METHODS

We performed a post hoc analysis of a prospective management outcome study for PE diagnosis in pregnant women. PE was diagnosed with an algorithm that combined the revised Geneva score, D-dimer testing, bilateral lower-limb compression ultrasonography, and CTPA. All women had a 3-month follow-up. All of the items necessary to use the YEARS algorithm were prospectively collected at the time of the study.

RESULTS

Of the 395 women included in the original study, 371 were available for the present analysis. The PE prevalence was 6.5%. Ninety-one women had no YEARS items, and 280 had one or more items. When the YEARS items were combined with D-dimer levels (<1000 ng/mL in women with no items, and <500 ng/mL in women with one or more items), 77 women (21%) met the criteria for PE exclusion and would not have undergone CTPA as per the YEARS algorithm. None of these 77 women had PE diagnosed during the initial work-up or 3-month follow-up. Therefore, the failure rate of the YEARS algorithm in our pregnant women population was 0/77 (95% confidence interval 0.0-3.9).

CONCLUSION

In our study, application of the YEARS algorithm would have resulted in safe exclusion of PE in one of five pregnant women without the need for radiation exposure, further supporting the use of the algorithm in this population.

Trends in Medical Imaging During Pregnancy in the United States and Ontario, Canada, 1996 to 2016

IMPORTANCE

The use of medical imaging has sharply increased over the last 2 decades. Imaging rates during pregnancy have not been quantified in a large, multisite study setting.

OBJECTIVE

To evaluate patterns of medical imaging during pregnancy.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was performed at 6 US integrated health care systems and in Ontario, Canada. Participants included pregnant women who gave birth to a live neonate of at least 24 weeks' gestation between January 1, 1996, and December 31, 2016, and who were enrolled in the health care system for the entire pregnancy.

EXPOSURES

Computed tomography (CT), magnetic resonance imaging, conventional radiography, angiography and fluoroscopy, and nuclear medicine.

MAIN OUTCOMES AND MEASURES

Imaging rates per pregnancy stratified by country and year of child's birth.

RESULTS

A total of 3 497 603 pregnancies in 2 211 789 women were included. Overall, 26% of pregnancies were from US sites. Most (92%) were in women aged 20 to 39 years, and 85% resulted in full-term births. Computed tomography imaging rates in the United States increased from 2.0 examinations/1000 pregnancies in 1996 to 11.4/1000 pregnancies in 2007, remained stable through 2010, and decreased to 9.3/1000 pregnancies by 2016, for an overall increase of 3.7-fold. Computed tomography rates in Ontario, Canada, increased more gradually by 2.0-fold, from 2.0/1000 pregnancies in 1996 to 6.2/1000 pregnancies in 2016, which was 33% lower than in the United States. Overall, 5.3% of pregnant women in US sites and 3.6% in Ontario underwent imaging with ionizing radiation, and 0.8% of women at US sites and 0.4% in Ontario underwent CT. Magnetic resonance imaging rates increased steadily from 1.0/1000 pregnancies in 1996 to 11.9/1000 pregnancies in 2016 in the United States and from 0.5/1000 pregnancies in 1996 to 9.8/1000 pregnancies in 2016 in Ontario, surpassing CT rates in 2013 in the United States and in 2007 in Ontario. In the United States, radiography rates doubled from 34.5/1000 pregnancies in 1996 to 72.6/1000 pregnancies in 1999 and then decreased to 47.6/1000 pregnancies in 2016; rates in Ontario slowly increased from 36.2/1000 pregnancies in 1996 to 44.7/1000 pregnancies in 2016. Angiography and fluoroscopy and nuclear medicine use rates were low (5.2/1000 pregnancies), but in most years, higher in Ontario than the United States. Imaging rates were highest for women who were younger than 20 years or aged 40 years or older, gave birth preterm, or were black, Native American, or Hispanic (US data only). Considering advanced imaging only, chest imaging of pregnant women was more likely to use CT in the United States and nuclear medicine imaging in Ontario.

CONCLUSIONS AND RELEVANCE

The use of CT during pregnancy substantially increased in the United States and Ontario over the past 2 decades. Imaging rates during pregnancy should be monitored to avoid unnecessary exposure of women and fetuses to ionizing radiation.

Pulmonary embolism management in the critical care setting

The American Heart Association (AHA) categorizes pulmonary embolism (PE) into three main categories based on the presence or absence of hemodynamic changes and evidence of right ventricular dysfunction. The AHA characterizes massive PE as occurring in the setting of persistent hypotension, profound bradycardia, or pulselessness; submassive PE as occurring with evidence of right ventricular dysfunction or myocardial necrosis in the absence of hemodynamic changes; and low-risk PE as occurring in the absence of markers of massive and submassive PE. This chapter provides an overview of how to identify and manage patients with submassive and massive pulmonary embolism. Delivery planning considerations are discussed. We also address the management of critically ill obstetric patients with respect to VTE risk. The American Heart Association (AHA) categorizes pulmonary embolism (PE) into three main categories based on the presence or absence of hemodynamic changes and evidence of right ventricular dysfunction. The AHA characterizes massive PE as occurring in the setting of persistent hypotension, profound bradycardia, or pulselessness; submassive PE as occurring with evidence of right ventricular dysfunction or myocardial necrosis in the absence of hemodynamic changes; and low-risk PE as occurring in the absence of markers of massive and submassive PE.¹ This chapter provides an overview of how to identify and manage patients with submassive and massive pulmonary embolism. Delivery planning considerations are discussed. We also address the management of critically ill obstetric patients with respect to VTE risk.

Diagnosis of Pulmonary Embolism During Pregnancy: A Multicenter Prospective Management Outcome Study

BACKGROUND

Data on the optimal diagnostic management of pregnant women with suspected pulmonary embolism (PE) are limited, and guidelines provide inconsistent recommendations on use of diagnostic tests.

OBJECTIVE

To prospectively validate a diagnostic strategy in pregnant women with suspected PE.

DESIGN

Multicenter, multinational, prospective diagnostic management outcome study involving pretest clinical probability assessment, high-sensitivity D-dimer testing, bilateral lower limb compression ultrasonography (CUS), and computed tomography pulmonary angiography (CTPA). (ClinicalTrials.gov: NCT00740454).

SETTING

11 centers in France and Switzerland between August 2008 and July 2016.

PATIENTS

Pregnant women with clinically suspected PE in emergency departments.

INTERVENTION

Pulmonary embolism was excluded in patients with a low or intermediate pretest clinical probability and a negative D-dimer result. All others underwent lower limb CUS and, if results were negative, CTPA. A ventilation-perfusion (V/Q) scan was done if CTPA results were inconclusive. Pulmonary embolism was excluded if results of the diagnostic work-up were negative, and untreated pregnant women had clinical follow-up at 3 months.

MEASUREMENTS

The primary outcome was the rate of adjudicated venous thromboembolic events during the 3-month follow-up.

RESULTS

441 women were assessed for eligibility, and 395 were included in the study. Among these, PE was diagnosed in 28 (7.1%) (proximal deep venous thrombosis found on ultrasonography [n = 7], positive CTPA result [n = 19], and high-probability V/Q scan [n = 2]) and excluded in 367 (clinical probability and negative D-dimer result [n = 46], negative CTPA result [n = 290], normal or low-probability V/Q scan [n = 17], and other reason [n = 14]). Twenty-two women received extended anticoagulation during follow-up, mainly for previous venous thromboembolic disease. The rate of symptomatic venous thromboembolic events was 0.0% (95% CI, 0.0% to 1.0%) among untreated women after exclusion of PE on the basis of negative results on the diagnostic work-up.

LIMITATION

There were several protocol deviations, reflecting the difficulty of performing studies in pregnant women with suspected PE.

CONCLUSION

A diagnostic strategy based on assessment of clinical probability, D-dimer measurement, CUS, and CTPA can safely rule out PE in pregnant women.

PRIMARY FUNDING SOURCE

Swiss National Foundation for Scientific Research, Groupe d'Etude de la Thrombose de Bretagne Occidentale, and International Society on Thrombosis and Haemostasis.

Management of Venous Thromboembolism in Pregnancy

PURPOSE OF REVIEW

This manuscript addresses the risks for venous thromboembolism (VTE) during pregnancy and the associated challenges of both diagnosis and treatment.

RECENT FINDINGS

The obstacles to diagnosis given lack of specificity of typical biomarkers to predict VTE in pregnancy, as well as the unique fetal and bleeding risks introduced by managing massive pulmonary embolism (PE) with thrombolytics or thrombectomy are highlighted. VTE during pregnancy and the postpartum window occurs at a 6-10-fold higher rate compared with age-matched peers and is a major cause of morbidity and mortality. Hypercoagulability persists for 6-8 weeks after delivery with the highest risk of PE being postpartum. The lack of randomized trials in pregnant women leads to variability in practice, which are largely based on expert consensus or extrapolation from non-pregnant cohorts. The standard treatment of VTE in pregnancy is anticoagulation with low molecular weight heparin (LMWH), which like unfractionated heparin does not cross the placenta and is not teratogenic. LMWH is preferred given the negligible risk for heparin-induced thrombocytopenia and osteoporosis, better bioavailability, and a predictive dose response. Depending on the severity of the VTE, additional treatments including thrombolysis, thrombectomy, inferior vena cava filter placement, or venous stenting may be used. Management requires balancing the competing bleeding and thrombotic risks during labor and delivery and factoring the impact of treatment on the fetus. A multidisciplinary team involving hematology, obstetrics, anesthesia, vascular medicine, and cardiology is critical for safe and timely management. The design and execution of prospective, randomized trials to specifically address optimal diagnosis and management are a top priority in obstetric hematology.

Magnetic resonance angiography for the primary diagnosis of pulmonary embolism: A review from the international workshop for pulmonary functional imaging

Pulmonary contrast enhanced magnetic resonance angiography (CE-MRA) is useful for the primary diagnosis of pulmonary embolism (PE). Many sites have chosen not to use CE-MRA as a first line of diagnostic tool for PE because of the speed and higher efficacy of computerized tomographic angiography (CTA). In this review, we discuss the strengths and weaknesses of CE-MRA and the appropriate imaging scenarios for the primary diagnosis of PE derived from our unique multi-institutional experience in this area. The optimal patient for this test has a low to intermediate suspicion for PE based on clinical decision rules. Patients in extremis are not candidates for this test. Younger women (< 35 years of age) and patients with iodinated contrast allergies are best served by using this modality We discuss the history of the use of this test, recent technical innovations, artifacts, direct and indirect findings for PE, ancillary findings, and the effectiveness (patient outcomes) of CE-MRA for the exclusion of PE. Current outcomes data shows that CE-MRA and NM V/Q scans are effective alternative tests to CTA for the primary diagnosis of PE.

Diagnosis and Management of VTE in Pregnancy

Venous thromboembolism is a leading cause of maternal death. Because of the low absolute frequency of events, however, outcome-based clinical data are limited. Consequently, clinicians must additionally rely both on published guidelines and on extrapolation of data from studies focused on nonpregnant individuals. The diagnosis and treatment of deep vein thrombosis, pulmonary embolism, and cerebral vein and dural sinus thrombosis are complicated by pregnancy, and often require modifications to standard diagnostic and treatment algorithms outside of pregnancy. Treatment of VTE in pregnant women is in particular need of future research.