Surveillance decision

Surveillance decision

We will plan an update of the following sections of the guideline:

  • Diagnostic investigations for pulmonary embolism (PE)

  • Pharmacological interventions – anticoagulation treatment for deep vein thrombosis (DVT) or PE[1]

  • Investigations for cancer

An extension to the scope will be needed to incorporate outpatient treatment of people with PE.

Reason for the decision

We found 59 new studies through surveillance of this guideline.

New evidence that could affect recommendations was identified. Topic experts, including those who helped to develop the guideline, advised us about whether the following sections of the guideline should be updated and any new sections added.

Diagnosis for pulmonary embolism (PE)

  • In people with suspected PE, can we safely rule out further imaging based on clinical probability score and D‑dimer assay?

The current recommendations do not specify a D‑dimer threshold to use in patients with an unlikely 2‑level PE Wells score. The evidence identified at the 4‑year surveillance review on D‑dimer thresholds to safely rule out further imaging has a potential impact on NICE guideline CG144. Topic experts highlighted the increase in false positive rates of D‑dimer with age when using unadjusted thresholds. An age adjusted D‑dimer may increase the proportion of patients, primarily over the age of 50, in whom further imaging can be safely withheld. In turn, this has the potential to reduce impact on resources and reduce the risks of imaging with less radiation exposure and complications from contrast injections. A further consideration of age adjusted D dimer concerns the use of different D‑dimer assays with varying cut‑off thresholds across services and laboratories. Although some topic experts believe this topic to be relatively low priority, most topic experts agreed that the new evidence suggests the current recommendation (1.1.10) to offer a D‑dimer test may need to be updated to include consideration of the patient's age when setting the threshold to rule out further imaging tests for PE. Some consideration should be given to the wording of any such new recommendation to suggest that each service validate its own D‑dimer assay and this could be influenced by the patient's age.

Decision: This review question should be updated.

Treatment – pharmacological interventions

  • What is the effectiveness of pharmacological interventions to manage patients with suspected or confirmed DVT?

  • What is the effectiveness of pharmacological interventions to manage patients with suspected or confirmed PE?

The evidence identified at the 4‑year review on pharmacological interventions with non‑vitamin K oral anticoagulants (NOACs) to manage DVT or PE has a potential impact on NICE guideline CG144. The 4‑year surveillance review identified new evidence for the efficacy and safety of NOACs which have not been previously considered in NICE guideline CG144. The evidence suggests similar rates of efficacy for NOACs compared with current standard treatments for confirmed venous thromboembolism (VTE) and a trend towards reduced risks of bleeding. NICE Technology Appraisals have, since the publication of NICE guideline CG144, approved the use of NOACs for the treatment and prevention of VTE.

Intelligence from topic experts also highlights the common practice for clinicians to use NOACs rather than a low molecular weight heparin (LMWH) for the treatment of suspected DVT prior to diagnosis. However, anticoagulant use may impair the reliability of subsequent D‑dimer assay results. Topic experts suggested guidance in this area would be useful.

Topic experts also highlighted that patients who have a negative proximal leg vein ultrasound scan for DVT but need a repeat scan one week later should not be treated. The rationale for the second scan is to determine if any undetected calf vein clots extend off treatment however pharmacotherapy may impair the reliability of subsequent ultrasound scan results. There is also a potential risk of a supressed calf vein clot extending if treatment is stopped after one week. Topic experts suggested that some clarity for clinicians in this area would be useful.

Topic experts agreed that the new evidence suggests the current recommendations on pharmacological interventions for VTE may need to be updated to include consideration of the use of NOACs as a treatment option and some clarity around treatment during diagnosis of DVT.

Decision: This review question should be updated.

Investigations for cancer

  • Do investigations for cancer in patients with spontaneous VTE (DVT or PE) improve patient outcomes (morbidity and mortality)?

The 4‑year surveillance review identified new evidence to suggest that CT scans of the abdomen and pelvis in addition to routine or limited screening do not provide a clinically significant benefit in diagnosis or mortality rates for cancer in patients with VTE. Intelligence from topic experts also highlights the lack of benefit in additional cancer screening and the increased risk of radiation from CT scans. This new evidence is inconsistent with the current recommendation to offer further investigations for cancer to all patients with unprovoked DVT or PE. Topic experts agreed that the new evidence suggests the current recommendations on investigations for cancer may need to be updated to reflect the new information on this question. Some consideration should be given to the wording of any such new recommendation to suggest that further screening with CT should be considered if guided by clinical assessment or if other risk factors are present.

Decision: This review question should be updated.

Outpatient treatment of patients with PE

  • Which patients with suspected or confirmed PE can be safely discharged and managed within outpatient settings?

  • What is the clinical and cost-effectiveness of outpatient treatment for the management of patients with low risk PE?

NICE guideline CG144 does not currently include recommendations regarding outpatient treatment of PE. New evidence from the 4‑year surveillance review suggests that patients with PE who are at low risk of adverse events could safely receive anticoagulation treatment on an outpatient basis. Topic experts highlighted the increased use of ambulatory care units as an alternative to hospital care and the use of mortality risk and Pulmonary Embolism Severity Index (PESI) scores to identify patients with a low risk of adverse events who could be safely discharged. Topic experts agreed that there is a need to establish a new area in the guideline to incorporate recommendations on outpatient treatment for PE.

Decision: This review question should be included.

Other clinical areas

Topic experts considered the effectiveness of whole-leg ultrasound scans for the diagnosis of DVT. The 4‑year surveillance review did not find any new evidence comparing the effectiveness of a whole-leg ultrasound scan with a proximal leg vein ultrasound scan for the detection of distal DVT. Topic experts suggest that there may be an indication for a whole-leg ultrasound scan in circumstances where a serial ultrasound is not available, when a repeat scan would be very difficult to arrange or in patients receiving an anticoagulant prior to a D‑dimer test. However, there remains some uncertainty of the clinical and cost-effectiveness of a whole-leg ultrasound scan in the diagnosis of DVT to impact recommendations at this time. This area will be examined again at the next surveillance review of the guideline.

We also found new evidence that was not thought to have an effect on current recommendations. This evidence related to self-management and self-monitoring for patients treated with a vitamin K antagonist.

We did not find any new evidence related to patient information or thrombophilia testing.

For any new evidence relating to published or ongoing NICE technology appraisals, the guideline surveillance review deferred to the technology appraisal decision.

Equalities

No equalities issues were identified during the surveillance process.

Overall decision

After considering all the new evidence and views of topic experts, we decided that a partial update with modified scope is necessary for this guideline.

See how we made the decision for further information.



[1] The proposed update to pharmacological interventions is limited to anticoagulant treatments and does not include pharmacological thrombolysis or analgesia.


This page was last updated: 03 November 2016