Pulmonary embolism in hospital practiceBMJ 2006; 332 doi: https://doi.org/10.1136/bmj.332.7534.156 (Published 19 January 2006) Cite this as: BMJ 2006;332:156
w1 Heit JA, Melton IL, Lohse CM, Petterson TM, Silverstein MD, Mohr DN, et al. Incidence of venous thromboembolism in hospitalized patients vs community residents. Mayo Clin Proc 2001;76:1102-10.
w2 Palmberg S, Hirsjarvi E. Mortality in geriatric surgery. With special reference to the type of surgery, anaesthesia, complicating diseases, and prophylaxis of thrombosis. Gerontology 1979;25:103-12.
w3 Huisman MV, Buller HR, ten Cate JW, van Royen EA, Vreeken J, Kersten MJ, et al. Unexpected high prevalence of silent pulmonary embolism in patients with deep venous thrombosis. Chest 1989;95:498-502.
w4 Goldhaber SZ. Seminar: pulmonary embolism. Lancet 2004;363:1295-305.
w5 Greaves M. Thrombophilia. Clin Med 2001;1:432-5.
w6 Aurangzeb I, George L, Raoof S. Amniotic fluid embolism. Crit Care Clin 2004;20:643-50.
w7 Fabian TC, Hoots AV, Stanford DS. Fat embolism syndrome: prospective evaluation in 92 fracture patients. Crit Care Med 1990;18:42-6.
w8 Wells PS, Anderson DR, Rodger M, Stiell I, Dreyer JF, Barnes D, et al. Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer. Ann Intern Med 2001;135:98-107.
w9 Kelly J, Rudd A, Lewis RR, Hunt BJ. Plasma D-dimers in the diagnosis of venous thromboembolism. Arch Intern Med 2002;162:747-56.
Posted as supplied by author.
Test your knowledge
1. In a patient with a high probability V/Q scan, but a low pre-test probability score, the next step should be:
A. Start warfarin and LMWH heparin
B. Start iv heparin
C. Repeat the d-dimer
E. Leg ultrasound
A: Incorrect. The diagnosis must be confirmed, or the pre-test clinical probability intermediate or high before anticoagulation is started.
B: Incorrect. There is no evidence to show iv heparin is more efficacious than LMWH, and as for answer A, anticoagulation should not be started in this situation.
C: Incorrect. The d-dimer is part of the pre-test clinical probability score, and should have been requested before any investigations, to help guide the most appropriate imaging.
D: Correct. When there is discordance between the lung scan and clinical probability score, a CTPA is recommended as the next investigation.
E: Incorrect. Up to 50% of patients with a clinically obvious DVT will have a high probability V/Q scan, and conversely around 70% of patients with proven PE will have a proximal DVT. Leg ultrasound can be used as an initial test to exclude the need for lung imaging, as the identification of a DVT excludes the need for other tests in the appropriate clinical scenario.
A. Is only useful at imaging clot, and is unhelpful in imaging the lung parenchyma.
B. Patients with a good quality negative CTPA do not need further imaging.
C. Quantitative clot measurement on CTPA correlates poorly with clinical severity.
D. Is as sensitive as V/Q scanning in patients with no underlying cardiorespiratory disease and a normal CXR.
E. Sub-segmental clot is seen better than on CTPA than on conventional pulmonary angiography.
A: Incorrect. One of the benefits of CTPA, is that it allows imaging of the mediastinum and lung parenchyma, and in the absence of PE, may allow an alternative diagnosis to be made.
B: Correct. The latest CT technology allows better diagnosis of more peripheral thrombus.
C: Incorrect. Volume of clot, as quantified by CTPA does correlate with clinical severity of disease.
D: Incorrect. CTPA has a sensitivity of over 95%. V/Q scanning is less sensitive, but can be useful if the CXR is normal, standard reporting is used, and if a non-diagnostic test is followed by further imaging.
E: Incorrect. Subsegmental clot is seen better on conventional pulmonary angiography, but better scanning protocols, and thin section scanning mean this is less of a problem.
3. Major risk factors for VTE include:
B. Cigarette smoking
C. Oral contraceptive pill
D. Congenital heart disease
E. Stage II lung cancer
A: Correct. The risk increases with length of pregnancy, and is highest in the puerperium. Caesarian section and multiple births increase the risk.
B: Incorrect. This was previously considered a risk factor, but is not now thought not to be associated.
C. Incorrect. This is a minor risk factor. Patients who have had a previous episode of proven VTE should be advised against taking the OCP.
D: Incorrect. This is a minor risk factor, increasing relative risk by a factor of 2-4.
E. Incorrect. Advanced or metastatic malignancy is a major risk factor, and occult malignancy is a minor risk factor.
4. VTE and oestrogens:
B. The oral contraceptive can be safely taken in those with a single previous episode of DVT or PE and no family history of VTE.
C. The greatest risk of PE with HRT is in the first year of use.
D. The risk of PE in pregnancy is highest in the first trimester.
E. Younger, primigravida women have the highest risk of VTE.
B: Incorrect. Any patient who has had a previous DVT or PE should be advised against the OCP.
C: Correct. Meta-analyses show a relative risk of VTE of 2.1 in HRT users, which is highest in the first year of use.
D: Incorrect. The risk of PE increases throughout pregnancy, with more PEs occuring after delivery than before.
E: Incorrect. The risk of PE in pregnancy increases with maternal age and multiple births.
5. Investigations for PE:
A. The S1Q3T3 ECG pattern is diagnostic of acute PE.
B. In a patient with a low or intermediate pre-test clinical probability negative d-dimer is reassuring.
C. D-dimer is 90% sensitive for diagnosing PE in in-patients.
D. A normal arterial blood gas confidently excludes the diagnosis of PE.
E. A DVT can be excluded with a good quality leg ultrasound.
A: Incorrect. The S1Q3T3 ECG pattern is uncommon and is not diagnostic, but may raise suspicion. Sinus tachycardia is the commonest ECG finding.
B: Correct: A negative d-dimer reliably excludes PE in patients with a low or intermediate pre-test clinical probability, and these patients do not need further investigation.
C: Incorrect. D-dimer has only been validated in out-patients. Its sensitivity in hospital in-patients is likely to be lower.
D: Incorrect. Hypoxia results from reduced cardiac output and a low mixed PO2 with ventilation/perfusion mismatching. A normal PO2 and alveolar arterial gradient is possible in a young, healthy person.
E: Incorrect. Leg ultrasound is only up to about 50% sensitive for detecting DVT, venography is about 60% sensitive.
6. Treatment for proven PE:
A. Warfarin and heparin should be started immediately the diagnosis is suspected.
B. Patients can be discharged home on day 2 of heparin treatment.
C. LMWH is as effective as unfractionated heparin in massive PE.
D. Warfarin is safe in pregnancy after the first trimester.
E. A PE diagnosed in pregnancy needs anticoagulation treatment for 6 months post delivery.
A: Incorrect. The diagnosis should be confirmed, or the pre-test clinical probability be intermediate or high before anticoagulation is started.
B: Correct. Studies are ongoing to assess the safety of out-patient PE management, in a carefully selected patient population. Guidelines suggest that out-patient DVT services should be extended to include PE treatment.
C: Incorrect. Unfractionated heparin has a quicker onset of action than LMWH, and it is recommended in massive and sub-massive PE or where rapid reversal of anti-coagulation may be needed.
D: Incorrect. Warfarin is teratogenic and is contraindicated in pregnancy. LMWH should be given. Unfractioned heparin should be given near to the time of delivery.
E: Incorrect. Anticoagulation should be given for 6 weeks after delivery, or 3 months following the initial episode, whichever is longer. Warfarin is safe in breast feeding.
7. Inherited thrombophilias:
A. Usually need to interact with an additional risk factor to cause VTE.
B. Can be tested for whilst the patient is on anticoagulants.
C. Heterogenous factor V Leiden deficiency is found in 20% of the population.
D. 90% of patients with VTE have an identifiable inherited thrombophilia.
E. All patients with VTE should be screened to identify undiagnosed malignancy.
A: Correct. Inherited thrombophilias usually need to interact with an additional risk factor to cause VTE.
B: Incorrect. Only Factor V Leiden (a genetic test) can be tested for whilst the patient is on anticoagulants. All other must be tested for off anticoagulation.
C: Incorrect. Heterogenous factor V Leiden deficiency is found in 5% of the population, but in around 20% of those with VTE.
D: Incorrect. Between 25 and 50% of patients with VTE have an identifiable thrombophilia. These include antiphospholipid syndrome, antithrombin III deficiency, protein C or S deficiency and prothrombin gene defects.
E: Incorrect. There is an increased risk of cancer being diagnosed within about one year of VTE diagnosis, particularly in those with no identifiable risk factors; however current guidelines do not recommend routine screening for malignancy, other than with routine blood tests, CXR and careful clinical assessment.
8. The clinical pre-test probability score:
A. Is useful only in those with a clinically obvious PE.
B. Should be completed once the D-dimer result is known
C. Includes an assessment of all risk factors for VTE
D. The use of the score in PE has been extrapolated from data obtained in DVT.
E. Includes a measure of heart rate.
A: Incorrect. The pre-test clinical probability score should be made in all patients will a clinical suspicion of PE.
B: Incorrect. The score should be completed when the patient is first seen, it is then used in association with the D-dimer result.
C: Incorrect. The score includes an assessment of the presence of major risk factors for VTE.
D: Correct. The use of a pre-test clinical probability score in PE has been based on the use of clinical probability scoring in DVT. It has been found to be equally valid and reproducible in PE.
E: Incorrect. The score includes clinical features consistent with PE (including a raised respiratory rate, haemoptysis and pleuritc chest pain). Heart rate is not a measure that is included in most standard scores.
- Letter Published: 09 February 2006; BMJ 332 doi:10.1136/bmj.332.7537.364-b
- Letter Published: 02 February 2006; BMJ 332 doi:10.1136/bmj.332.7536.304
- Letter Published: 09 February 2006; BMJ 332 doi:10.1136/bmj.332.7537.364-a
- LetterPulmonary embolism in hospital practice: View from primary care is chest pain and breathlessness, but not togetherPublished: 02 February 2006; BMJ 332 doi:10.1136/bmj.332.7536.304-a
- Letter Published: 02 February 2006; BMJ 332 doi:10.1136/bmj.332.7536.304-b
- Editor's Choice Published: 20 April 2006; BMJ 332 doi:10.1136/bmj.332.7547.0-f
- Doctors in Pakistan call for workers deported from the UAE to be screened for HIVBMJ December 05, 2016, 355 i6544; DOI: https://doi.org/10.1136/bmj.i6544
- Time for guidelines on safety netting?BMJ December 05, 2016, 355 i6411; DOI: https://doi.org/10.1136/bmj.i6411
- The BMJ Christmas appeal 2016-7: Orbis, the sight saversBMJ December 01, 2016, 355 i6425; DOI: https://doi.org/10.1136/bmj.i6425
- Association between screening and the thyroid cancer “epidemic” in South Korea: evidence from a nationwide studyBMJ November 30, 2016, 355 i5745; DOI: https://doi.org/10.1136/bmj.i5745
- Overdiagnosis of thyroid cancerBMJ November 30, 2016, 355 i6312; DOI: https://doi.org/10.1136/bmj.i6312
- Venous thromboembolism: Stockings are important
- Venous thromboembolism: Heparins are of porcine origin
- Pulmonary embolism in hospital practice: View from primary care is chest pain and breathlessness, but not together
- Pulmonary embolism in hospital practice: Certain crucial procedures were omitted