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.............................. include reducing the anatomical coverage of the scan,393 reducing the kilovoltage, using iterative reconstructive techniques, and reducing the contrast-monitoring component of the CTPA.392,393 Modern CTPA imaging techniques may therefore expose the maternal breast to median doses as low as 34 mGy (Table 12).392 The effect on maternal cancer risk with modern CTPA techniques is negligible (lifetime cancer risk is reportedly increased by a factor of 1.00031.0007); avoiding CTPA on the grounds of maternal cancer risk is therefore not justified.394 A normal perfusion scan and a negative CTPA appear equally safe for ruling out PE in pregnancy, as suggested by retrospective series.385,386,402404 Inconclusive results can be a problem (433% of investigations),385,386,405 especially late in pregnancy.405 A recent survey of 24 sites in the UK, representing a population of 15.5 million, revealed a similar rate of inadequate or indeterminate CTPA and scintigraphy scans, suggesting that the initial choice of imaging is best determined by local expertise and resources.406

V/Q SPECT is associated with low foetal and maternal radiation exposure, and has promise in PE diagnosis in pregnancy.407 However,

©ESC 2019

Negative Indeterminate or positive

Proximal DVT not present

SUSPECTED PE DURING PREGNANCY

High pretest probability, or intermediate/low

probability and positive D-dimer result

Anticoagulate with LMWH

SPECIFIC INVESTIGATION FOR PE • If chest X-ray normal => CTPA or perfusion lung scan • If chest X-ray abnormala => CTPAc

• Chest X-raya • Compression proximal duplex ultrasound, if symptoms or signs suggestive of DVTb

Review by radiologist or nuclear physician experienced in diagnosis

of PE in pregnancy

PE ruled out Negative

Proximal DVT present

Positive

• Continue with LMWH at therapeutic dosed • Assess PE severity and the risk of early deathe • Refer to multidisciplinary team with experience of PE management in pregnancy • Provide plan to guide management of pregnancy, labour and delivery, postnatal and future care

Figure 7 Diagnostic workup and management of suspected pulmonary embolism during pregnancy, and up to 6 weeks post-partum. CTPA= computed tomography pulmonary angiography; CUS = compression ultrasonography; DVT= deep vein thrombosis; LMWH = low-molecularweight heparin; PE = pulmonary embolism. aIf chest X-ray abnormal, consider also alternative cause of chest symptoms. bDVT in pelvic veins may not be ruled out by CUS. If the entire leg is swollen, or there is buttock pain or other symptoms suggestive of pelvic thrombosis, consider magnetic resonance venography to rule out DVT. cCTPA technique must ensure very low foetal radiation exposure (see Table 12). dPerform full blood count (to measure haemoglobin and platelet count) and calculate creatinine clearance before administration. Assess bleeding risk and ensure absence of contra-indications. eSee Table 8. Downloaded from academic.oup.com/eurheartj/article/41/4/543/5556136 by guest on 07 October 2026