Objectives. Materials and Methods

Transcription

1 Imaging pulmonary embolism in pregnancy: What is the value of routine bilateral leg Doppler ultrasound in women without symptoms of deep venous thrombosis? Poster No.: E-0019 Congress: ESTI 2012 Type: Authors: Keywords: Scientific Exhibit M. Cooper, S. Matthews; Sheffield/UK Embolism / Thrombosis, Audit and standards, Ultrasound, Nuclear medicine conventional, CT-Angiography, Respiratory system, Obstetrics (Pregnancy, birth, postnatal period) Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 8

2 Objectives Pulmonary embolism (PE) is one of the leading causes of maternal death in the United Kingdom [1]. The diagnosis of PE in pregnancy is difficult due to the overlap between signs and symptoms of venous thromboembolic disease (VTE) and the physiological changes of pregnancy. Therefore, a high index of clinical suspicion and a timely and accurate diagnostic approach are required. The Royal College of Obstetricians and Gynaecologists (RCOG) Guideline (2007) recommends routine bilateral leg Doppler ultrasound in pregnant women suspected of having acute PE, even in the absence of leg symptoms [2]. The aim is to detect deep venous thrombosis (DVT), which forms part of the spectrum of venous thromboembolic disease, and should be treated as for PE, without resort to ionizing radiation and its associated risks to mother and foetus. The Sheffield Teaching Hospitals protocol for imaging suspected pulmonary embolism in pregnancy, introduced in 2004, advises bilateral leg Doppler ultrasound in all women as a first line investigation. However, it appeared that few of these investigations yielded a positive result. Therefore, this study aimed to assess the detection rate of DVT on bilateral leg Doppler ultrasound in pregnant women without symptoms or signs of DVT but suspected of having pulmonary embolism to determine the usefulness of this investigation. Materials and Methods All cases pregnant patients undergoing bilateral leg Doppler ultrasound for the investigation of PE at our institution over a two year period ( ) were reviewed. The cases were identified retrospectively from the hospital radiology information system. Data recorded included: Presence/absence of leg symptoms of DVT Trimester of pregnancy D dimer Doppler ultrasound scan result Final diagnosis (Venous thromboembolic disease present/absent) This service review was approved by the Trust's Clinical Audit and Effectiveness Unit. Page 2 of 8

3 Results 156 pregnant women had bilateral leg Doppler scans for the investigation of suspected acute PE during the study period. The majority of patients were in the third trimester of pregnancy. (Figure 1) The D dimer was performed in 108 of the 156 patients. This was normal in only 4 patients (3.8%); none was normal in the third trimester of pregnancy. (Figure 2) Bilateral leg Doppler ultrasound scans were performed in 156 patients. 20 (13%) women had leg symptoms. DVT was detected in a single patient suspected of having PE (0.6%). This patient had symptoms and signs consistent with DVT. There was one indeterminate scan. In 154 (98.8%) patients, DVT was excluded. Asymptomatic DVT was not detected. (Figure 3) Following a normal or an indeterminate leg Doppler ultrasound scan, 140 women underwent further investigation. 103 patients had a radioisotope perfusion scan. This was normal in 79 patients (i.e. PE excluded), indeterminate in 12 patients and highly suspicious of acute pulmonary embolism in 12 patients. 37 patients had CT pulmonary angiography as a first line investigation. This was normal in 35 cases, indeterminate in 1 case and confirmed acute PE in 1 case. Following an indeterminate perfusion scan, all 12 patients had CT pulmonary angiography. CT pulmonary angiography following perfusion scan confirmed 3 patients with acute PE. Therefore, DVT was diagnosed in 1 patient (0.6%) and PE in 4 patients (2.6%). Venous thromboembolic disease was confirmed in 3.2% of the study population. (Figure 4) Images for this section: Page 3 of 8

4 Fig. 1: Number of women in each trimester (actual number and % of total). Page 4 of 8

5 Fig. 2: Result of D dimer by trimester of pregnancy. Page 5 of 8

6 Fig. 3: Result of Doppler scan in patients with and without symptoms of DVT. Page 6 of 8

7 Fig. 4: Results of investigations following bilateral leg Doppler ultrasound. (Negative = VTE excluded, positive = VTE confirmed). Page 7 of 8

8 Conclusions Unsuspected DVT was not diagnosed in any patient without leg symptoms and was detected in only 5% of those with symptoms. Although the RCOG 2007 guideline advises this investigation, the supporting references within the document conclude that this investigation is, at best, of limited value in patients lacking leg symptoms suggestive of deep vein thrombosis. This is consistent with the finding of the current study. The American Thoracic Society (ATS) guidelines 2012 recommend bilateral leg Doppler ultrasound only if the mother has leg symptoms. (3) The reasons for bilateral Doppler ultrasound, rather than investigation of the symptomatic leg only, are not clarified. This study confirmed that a D dimer assay was unlikely to be diagnostically helpful in the pregnant patient investigated for suspect pulmonary embolism owing to the natural rise in this assay as pregnancy advances. Therefore, a D dimer assay is not recommended. This finding concurs with the RCOG 2007 and ATS 2012 guidelines. Therefore, it is advised that pregnant women in whom pulmonary embolism is suspected should undergo clinical assessment and be referred for leg Doppler ultrasound only in the presence of signs and symptoms that support the diagnosis of DVT. Otherwise, the patient should be referred for a radioisotope perfusion scan or CT pulmonary angiogram, dependent on the appearances of the chest radiograph. In conclusion, there is no role for routine bilateral leg Doppler ultrasound in pregnant women investigated for suspected PE in the absence of leg symptoms. References: 1. Centre for Maternal and Child Enquiries (CEMACE). Saving Mothers lives: reviewing maternal deaths to make motherhood safer: The eighth report on confidential enquiries into maternal deaths in the United Kingsom. BJOG 2011;118 (supl.1): Thromboembolic Disease in Pregnancy and the Puerperium: Acute Management. RCOG (2007) Green-top Guideline No American Thoracic Society Documents: An official American Thoracic Society/Society of Thoracic Radiology Clinical Practice Guideline - Evaluation of suspected pulmonary embolism in pregnancy. Radiology 2012; 262: Page 8 of 8