Pulmonary embolism — structured written assessment

SAQ 1 (10 marks)

Practice scenario. A 48-year-old woman presents to the emergency department with 2 days of pleuritic chest pain and breathlessness. She is not pregnant and takes a combined oral contraceptive. Heart rate 104/min, blood pressure (BP) 126/80 mmHg, oxygen saturation 95% on air; she is alert and has no leg signs. She has not been anticoagulated.^[1]

1. Outline how the 2019 ESC guideline asks you to assess her clinical probability of pulmonary embolism (PE), naming one validated rule. (2)^[1][2]
2. Her probability is intermediate. Give the ESC recommendations, with class and level, on anticoagulation while she is investigated and on D-dimer testing, including the alternative cut-offs. (4)^[2]
3. Her D-dimer is raised and CT pulmonary angiography (CTPA) shows a segmental filling defect. State the ESC recommendation on accepting the diagnosis and name two things CTPA can add beyond diagnosis. (2)^[1][2]
4. Name two situations in which ESC 2019 says the ventilation/perfusion (V/Q) scan may preferentially be applied. (2)^[1]

Model answers

• Q1. ESC 2019 recommends a diagnostic strategy based on clinical probability, assessed either by clinical judgement or by a validated prediction rule (Class I, level A); the most frequently used rules are the revised Geneva rule and the Wells rule.^[1][2]
• Q2 (anticoagulation). ESC 2019: initiation of anticoagulation is recommended without delay in patients with high or intermediate clinical probability while the diagnostic work-up is in progress (Class I, level C).^[2]
• Q2 (D-dimer). ESC 2019: plasma D-dimer, preferably with a highly sensitive assay, is recommended in outpatients/emergency department patients with low or intermediate clinical probability, or who are PE-unlikely, to reduce unnecessary imaging and irradiation (Class I, level A). As an alternative to the fixed cut-off, a negative D-dimer using an age-adjusted cut-off (age × 10 μg/L, in patients aged over 50 years) should be considered for excluding PE in patients with low or intermediate probability or who are PE-unlikely (Class IIa, level B; not applicable to her at 48 years); as an alternative to the fixed or age-adjusted cut-off, D-dimer levels adapted to clinical probability should be considered to exclude PE (Class IIa, level B); its footnote says cut-offs according to the YEARS model (signs of deep vein thrombosis [DVT], haemoptysis, and whether an alternative diagnosis is less likely than PE) may be used: PE is excluded in patients without clinical items and D-dimer under 1000 µg/L, or with one or more clinical items and D-dimer under 500 µg/L.^[2]
• Q3. ESC 2019: it is recommended to accept the diagnosis of PE without further testing if CTPA shows a segmental or more proximal filling defect in a patient with intermediate or high clinical probability (Class I, level B). Beyond diagnosis, CTPA may provide an alternative diagnosis if PE is excluded (ESC Table 6), and four-chamber views by CT angiography can detect right ventricular (RV) enlargement (RV end-diastolic diameter and RV/LV ratio) as an indicator of RV dysfunction.^[1][2]
• Q4 (any two). Outpatients with a low clinical probability and a normal chest X-ray; young (particularly female) patients; pregnant women; patients with a history of contrast medium-induced anaphylaxis; patients with severe renal failure.^[1]

SAQ 2 (10 marks)

Practice scenario. A 59-year-old man has PE confirmed on CTPA. BP 112/70 mmHg, heart rate 118/min, oxygen saturation 89% on air; there has been no cardiac arrest, hypotension or shock. His simplified Pulmonary Embolism Severity Index (sPESI) is 2, the CTPA shows an RV/LV diameter ratio of 1.3, and his troponin T is raised. Creatinine clearance is 80 mL/min. He has no cancer and no known antiphospholipid antibody syndrome.^[1]

1. Classify his risk using the 2019 ESC scheme and justify it. (2)^[1][2]
2. Outline his ESC 2019 management over the first 72 hours, including the role of thrombolysis, with classes and levels. (4)^[1][2]
3. Summarise the PEITHO trial. (2)^[5]
4. He stabilises. Outline the 2019 ESC choice of oral anticoagulant and how the duration will be decided. (2)^[2]

Model answers

• Q1. He has no haemodynamic instability, so he is not high risk. His sPESI of 1 or more places him in the intermediate-risk group (30-day mortality risk 10.9% with 1 point or more), and with evidence of both RV dysfunction (RV/LV 1.3 on CTPA) and an elevated cardiac biomarker (positive troponin), ESC 2019 classifies him as intermediate-high risk.^[1][2]
• Q2 (anticoagulation and monitoring). ESC 2019: hospitalise him; patients with RV dysfunction plus a positive troponin should be monitored over the first hours or days because of the risk of early decompensation and circulatory collapse. If anticoagulation is started parenterally, low-molecular-weight heparin (LMWH) or fondaparinux is recommended over unfractionated heparin (UFH) for most patients (Class I, level A); ESC 2019 says it appears reasonable to leave intermediate-high-risk patients on LMWH over the first 2–3 days and ensure they remain stable before switching to oral anticoagulation.^[1][2]
• Q2 (thrombolysis). ESC 2019: routine use of primary systemic thrombolysis is not recommended in intermediate- or low-risk PE (Class III, level B). Rescue thrombolytic therapy is recommended for haemodynamic deterioration on anticoagulation (Class I, level B); as an alternative, surgical embolectomy or catheter-directed treatment should be considered (Class IIa, level C), if appropriate expertise and resources are available on-site; ESC notes that the risk-to-benefit ratios of surgical embolectomy or catheter-directed procedures have not yet been established in intermediate- or low-risk PE. Supplemental oxygen is indicated in patients with PE and an arterial oxygen saturation under 90%, as here.^[1][2]
• Q3. PEITHO was a randomised, double-blind trial of tenecteplase plus heparin vs placebo plus heparin in normotensive patients with intermediate-risk PE (RV dysfunction on echocardiography or CT plus a positive troponin). Death or haemodynamic decompensation within 7 days occurred in 2.6% vs 5.6% (OR 0.44; P=0.02), but extracranial bleeding was 6.3% vs 1.2% and stroke 2.4% vs 0.2%; death by day 30 was 2.4% vs 3.2% (P=0.42).^[5]
• Q4. ESC 2019: when oral anticoagulation is started in a patient eligible for a non-vitamin K antagonist oral anticoagulant (NOAC: apixaban, dabigatran, edoxaban or rivaroxaban), a NOAC is recommended in preference to a vitamin K antagonist (VKA) (Class I, level A); for intermediate-high-risk PE, ESC 2019 says it appears reasonable to leave patients on LMWH over the first 2–3 days and ensure they remain stable before switching to oral anticoagulation, and the specifications concerning the increased initial dose of apixaban or rivaroxaban (for 1 and 3 weeks after PE diagnosis, respectively), or the minimum overall period (5 days) of heparin anticoagulation before switching to dabigatran or edoxaban, must be followed. Therapeutic anticoagulation for 3 months or more is recommended for all patients with PE (Class I, level A). Beyond that, the decision depends on the risk factor behind the index event (for example, discontinuation is recommended after 3 months for a first PE secondary to a major transient/reversible risk factor, Class I, level B), and his bleeding risk should be assessed to identify and treat modifiable bleeding risk factors, and it may influence decision-making on the duration and regimen/dose of anticoagulant treatment.^[1][2]