Diagnosis of venous thromboembolism in pregnancy: a study in extrapolation or a science in evolution?

Advances in the Diagnosis of Venous Thromboembolism: A Literature Review

The incidence of venous thromboembolism (VTE), including lower extremity deep vein thrombosis (DVT) and pulmonary embolism (PE) is increasing. The increase in suspicion for VTE has lowered the threshold for performing imaging studies to confirm diagnosis of VTE. However, only 20% of suspected cases have a confirmed diagnosis of VTE. Development of pulmonary embolism rule-out criteria (PERC) and update in pre-test probability have changed the paradigm of ruling-out patient with low index of suspicion. The D-dimer test in conjunction to the pre-test probability has been utilized in VTE diagnosis. The age appropriate D-dimer cutoff and inclusion of YEARS algorithm (signs of the DVT, hemoptysis and whether PE is the likely diagnosis) for the D-dimer cutoff have been recent updates in the evaluation of suspected PE. Multi-detector computed tomography pulmonary angiography (CTPA) and compression ultrasound (CUS) are the preferred imaging modality to diagnose PE and DVT respectively. The VTE diagnostic algorithm do differ in pregnant individuals. The prerequisite of avoiding excessive radiation has recruited planar ventilation-perfusion (V/Q) scan as preferred in pregnant patients to evaluate for PE. The modification of CUS protocol with addition of the Valsalva maneuver should be performed while evaluating DVT in pregnant individual.

Towards complication-free assisted reproduction technology

Assisted reproductive technology (ART) has vastly improved over the last 40 years, from a frequently unsuccessful and complicated procedure requiring hospital admission and routine laparoscopy to a fairly simple outpatient technique with relatively high success rates. However, it is important to stress that ART is not without risk and medical complications may still occur. The incidence of most of these ART-related complications is associated with how women undergo ovarian stimulation. For this reason, physicians should be aware that a carefully thought-out ovarian stimulation protocol and cycle monitoring are of paramount importance to maximise the success of the treatment while avoiding potentially life-threating complications to occur in this frequently otherwise healthy patient population. This review discusses the rationale and evolution of ovarian stimulation strategies over the years and the current developments towards finding a balance between the retrieval of a sufficient number of oocytes and ART-related complication prevention.

Diagnostic value of single complete compression ultrasonography in pregnant and postpartum women with suspected deep vein thrombosis: prospective study

OBJECTIVE

To assess the safety of using single complete compression ultrasonography in pregnant and postpartum women to rule out deep vein thrombosis.

DESIGN

Prospective outcome study.

SETTING

Two tertiary care centres and 18 private practices specialising in vascular medicine in France and Switzerland.

PARTICIPANTS

226 pregnant and postpartum women referred for suspected deep vein thrombosis.

METHODS

A single proximal and distal compression ultrasonography was performed. All women with a negative complete compression ultrasonography result did not receive anticoagulant therapy and were followed up for a three month period.

MAIN OUTCOME MEASURES

Symptoms of venous thromboembolism, second compression ultrasonography or chest imaging, a thromboembolic event, and anticoagulant treatment.

RESULTS

16 women were excluded, mainly because of associated suspected pulmonary embolism. Deep vein thrombosis was diagnosed in 22 out of the 210 included women (10.5%). 10 patients received full dose anticoagulation despite a negative test result during follow-up. Of the 177 patients without deep vein thrombosis and who did not receive full dose anticoagulant therapy, two (1.1%, 95% confidence interval 0.3% to 4.0%) had an objectively confirmed deep vein thrombosis during follow-up.

CONCLUSIONS

The rate of venous thromboembolic events after single complete compression ultrasonography in pregnant and postpartum women seems to be within the range of that observed in studies in the non-pregnant population. These data suggest that a negative single complete compression ultrasonography result may safely exclude the diagnosis of deep vein thrombosis in this setting.

TRIAL REGISTRATION

clinicaltrials.gov NCT00740454.

Diagnosis of DVT: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Objective testing for DVT is crucial because clinical assessment alone is unreliable and the consequences of misdiagnosis are serious. This guideline focuses on the identification of optimal strategies for the diagnosis of DVT in ambulatory adults.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that clinical assessment of pretest probability of DVT, rather than performing the same tests in all patients, should guide the diagnostic process for a first lower extremity DVT (Grade 2B). In patients with a low pretest probability of first lower extremity DVT, we recommend initial testing with D-dimer or ultrasound (US) of the proximal veins over no diagnostic testing (Grade 1B), venography (Grade 1B), or whole-leg US (Grade 2B). In patients with moderate pretest probability, we recommend initial testing with a highly sensitive D-dimer, proximal compression US, or whole-leg US rather than no testing (Grade 1B) or venography (Grade 1B). In patients with a high pretest probability, we recommend proximal compression or whole-leg US over no testing (Grade 1B) or venography (Grade 1B).

CONCLUSIONS

Favored strategies for diagnosis of first DVT combine use of pretest probability assessment, D-dimer, and US. There is lower-quality evidence available to guide diagnosis of recurrent DVT, upper extremity DVT, and DVT during pregnancy.

Imaging evaluation of the pregnant patient with suspected pulmonary embolism

Pulmonary embolism is the leading cause of maternal death in the developed world. The clinical diagnosis of pulmonary embolism is particularly challenging in pregnant patients as physiologic changes of pregnancy can mimic symptoms of pulmonary embolism or deep venous thrombosis. Clinical decision and imaging algorithms for venous thromboembolic disease have been proposed in the literature for the general population, but have not undergone wide-scale validation in pregnant patients. Laboratory evaluation of D-dimer levels has likewise been established as a viable screening method in the general population but remains controversial in pregnant patients. Regardless of whether D-dimer levels are used in this population, the clinician must often rely on imaging tests to confirm or exclude a clinical suspicion of pulmonary embolism. Additional factors beyond test performance must be weighed during pregnancy: radiation exposure to the fetus and maternal breast tissue, the safety of intravenous contrast administration and the diagnostic accuracy of the various testing options so that diagnosis and proper management are not delayed. The epidemiology of pregnancy-related venous thromboembolic disease and the different diagnostic methods are reviewed, with emphasis on the pregnant patient. Finally, a diagnostic imaging algorithm is proposed for the evaluation of the pregnant patient when a clinical suspicion of pulmonary embolism exists.