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Virtual risk assessment pathway for deep venous thrombosis: a preliminary model
  1. Mr Karthikeyan P Iyengar1,
  2. Vijay Kumar Jain2,
  3. Manjusha Soni3,
  4. Zuned Hakim1
  1. 1 Department of Orthopaedics, Southport and Ormskirk Hospital NHS Trust, Southport, UK
  2. 2 Department of Orthopaedics, Atal Bihari Vajpayee Institute of Medical Sciences, Dr Ram Manohar Lohia Hospital, New Delhi, India
  3. 3 Department of Acute Medicine, Warrington and Halton General District Hospital, Warrington, UK
  1. Correspondence to Vijay Kumar Jain, Department of Orthopaedics, Atal Bihari Vajpayee Institute of Medical Sciences, Dr. Ram Manohar Lohia Hospital, New Delhi, 110001; drvijayortho{at}


Background COVID-19 has necessitated the reduction in conventional face-to-face patient consultation to reduce the risk of novel coronavirus SARS-CoV-2 transmission. Traditional pathways to risk assess for deep venous thrombosis (DVT) would involve face-to-face assessment to formulate an appropriate management plan following an initial presentation usually in secondary care or in-hospital settings. Appropriate antithrombotic measures can prevent complication of DVT such as pulmonary embolism with prompt early diagnosis and treatment.

Methods This observational, pilot study evaluates the possibility of combining telemedicine technology and a virtual examination pathway for remote triage and assessment of patients with suspected DVT.

Results Piloting and development of a virtual risk assessment pathway for DVT involves various challenges and multidisciplinary co-ordination.

Conclusion Advances in telecommunication technology can enable clinicians, specialist nurses and hospital departments to develop a virtual examination pathway for remote triage and assessment of patients with suspected DVT. This pathway is not a replacement for conventional ‘face-to-face’ evaluation, but we believe the template can be explored and refined to act as a blueprint for future applications even when the pandemic has stabilised.

  • Vascular medicine
  • cardiology
  • thromboembolism
  • education & training (see medical education & training)
  • haematology
  • bleeding disorders & coagulopathies
  • health services administration & management
  • health economics

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COVID-19 pandemic has resulted in a profound impact on the delivery of healthcare. The novel coronavirus SARS-CoV-2 outbreak has limited the traditional ‘face-to-face’ interaction between a clinician and a patient due to social distancing and infection prevention strategies to prevent viral transmission.1 2 This has necessitated a shift away from in-hospital visits, reduced ‘face-to-face’ outpatient and general practitioner clinic appointments and a search for innovative ways to address patient continuity of care.3 COVID-19 has introduced a new conundrum in the natural history of venous thromboembolism (VTE). VTE often manifests clinically as deep vein thrombosis (DVT) or pulmonary embolism (PE). DVT of the lower limb commonly starts in the deep calf veins. Of these thrombi 10% to 20% can propagate proximally and may lead to fatal PE. Appropriate antithrombotic measures can prevent this complication with prompt early diagnosis and treatment. It has been acknowledged that COVID-19 is associated with inflammation and a prothrombotic condition.4 COVID-19 associated coagulopathy is common in patients with associated cardiovascular risk factors such as hypertension and coronary artery disease.5 6 Cardiovascular disease is a strong risk factor for rapid progression and bad prognosis of COVID-19.7 Higher incidence of thrombotic complications has been seen in patients with severe SARS-CoV-2 infection and in patients who are critically ill in the intensive care unit.8 There is an urgent call to introduce closed ultrasound screening and monitoring for VTE in hospitalised patients9 and the need to be vigilant about VTE during the COVID-19 pandemic in the community. These mechanisms may be possible to initiate in a hospital setting; however, at-risk patients in the community may benefit from a virtual assessment for VTE especially due to the limitations posed by reduced face-to-face interactions and community care visits. Advances in information and communication technology with the availability of web-based telecommunication platforms have made it possible to deliver healthcare by remote medical consultation.10 11 COVID-19 has triggered an accelerated development of telemedicine (TM) in patient care both at primary and secondary care.12 TM applications have been used in the management of various musculoskeletal injuries.13 14 TM has been explored for virtual orthopaedic examination, and remote orthopaedic consultations have been found to be convenient and cost-effective.15 16

Combining TM technology using real-time synchronous audio–video transmission and a virtual examination technique may provide a remote triage and assessment of patients suspected of DVT, a common cause of VTE. The proposed model can be tried, re-enforced during this current pandemic. This will allow optimal utilisation of stretched hospital resources, support social distancing/infection prevention guidelines during the current COVID-19 pandemic and may be a model of such remote assessment of DVT in the future when the risk of COVID-19 has reduced.

Deep venous thrombosis

VTE is a term used to describe how thrombi form in a vein and break off to embolise into the vascular system. This includes DVT and PE. The European Society of Cardiology guidelines for the diagnosis and management of PE report annual incidence rates of venous thrombosis and PE of approximately 0.5–1.0 per 1000 inhabitants.17 DVT is a common VTE disorder with the formation of a thrombus in a deep vein, usually of the lower limbs and can lead non-fatal or fatal PE including include post-thrombotic syndrome.18 19 In the community, patients with DVT commonly present with pain, swelling and redness of the affected limb. The patient is then referred to secondary care or a hospital for confirmation of the diagnosis and initiation of anticoagulation. Despite National Institute of Health and Care Excellence (NICE) guidelines, the early management of DVT in UK hospitals varies broadly with a wide variation in clinical pathways across the National Health Service (NHS) hospitals.20 A remote assessment model will be useful in preliminary evaluation of patients at home or in the community care home settings.


TM portal set-up

The virtual DVT consultation system will require infrastructure organisation with setting up of ‘virtual consultation portals’. Availability of appropriate TM applications including compatible computer or mobile devices with fast fibre broadband internet connectivity is essential for reliable image transfer. Various web-based platforms are being used for video consultations. The common ones include Zoom, Microsoft Teams, Cisco Webex. There have been growing concerns about data security with some of these platforms. To address this implementation of ‘Attend Anywhere’, NHS digital web-based platform supported and promoted by the NHS Improvement as a part of national digital strategy will allow a safe and secure link with the patients.21 The video applications will have to be downloaded on both the clinician and patient’s computer, laptop or smartphone.


Remote access to electronic patient record and complementary radiology imaging systems such as patient archiving and communication system and patient administration system such as Medway for biochemical, haematological or histo-pathological investigations included in the NHS records will be helpful to understand patient clinical condition during the virtual consultation. The patient archives including medical and surgical history, medications, allergies, social and family history will allow clinicians to populate the virtual clinical assessment template for DVT (table 1).

Table 1

Virtual clinical risk assessment template for deep venous thrombosis

Virtual ‘handshake’

Once the video consultation link has been established with the patient, preliminary introductions are made to confirm the identity of the patient. A valid consent is obtained for remote consultation. The General Medical Council has published TM practice guidelines that apply to remote consultations as to any other, for example, face-to-face consultations.22 The patient will need an explanation about how the consultation is going to progress and limitations of the virtual consultation. Ancillary staff attending the appointment are introduced. Appropriate clothing, dressing and camera positioning for the virtual clinical examination will need to be explained to the patient.

Undertaking patient history

The diagnosis of DVT relies on assessment of the patient’s history and physical examination, risk stratification, followed by imaging.23 Pain and swelling of the involved extremity are the most common symptoms of DVT. Pain can be felt like cramping or soreness of the leg. There may be subtle ankle and calf swelling with slight pain, but if the clot is extensive then the entire leg can be swollen, tight, discoloured and painful. The other symptoms of DVT include redness, mild fever, superficial vein dilatation or bluish discolouration. A history of underlying risk factors, medications and recent surgical procedure of major joints within 4 weeks or recent immobilisation should be obtained from the patient with suspected DVT (table 1). Patients tested positive for COVID-19 are considered to have a hypercoagulable state and are at an increased risk for a broad range of vascular sequelae including DVT.24 Concurrent or recent onset of COVID-19 symptoms such as fever, running nose, sore throat continuous dry cough, tiredness, gastrointestinal symptoms such as diarrhoea and change or loss of smell and/or taste should be obtained from every patient. It may be difficult to ascertain the symptoms of PE; however, shortness of breath, pleuritic chest pain, dizziness or fainting, palpitations, blue lips or face, coughing up blood, etc., should be enquired. Patients with these symptoms should be asked to visit hospital immediately for further diagnosis and management.

Virtual clinical examination

The physical examination should be done in a well-lit room. The camera of the patient should face the patient from the front. Patient should be seated on a chair with eye at the level of the camera. The feet are flat on the floor and knees bent. If bed bound, knees are bent and feet flat. The examination findings of vitals such as blood pressure, temperature and pulse rate are noted from the patient if possible.

The leg and ankle examination includes core examination consisting of look (inspection), feel (palpation) and movement assessment.


Bilateral lower extremities should be evaluated for swelling of the leg or calf, any sign of inflammation, bluish discolouration and dilated veins. Severity of swelling, that is, involving the entire leg or only ankle and foot region should be noted. Surgical scars if the patient has a history of any previous surgery should observed. The virtual examination should include both standing and seated positions, with camera views from the front, side and back of the leg and ankle.


The patient should be asked to use the back of their hand to compare the temperature of the calf. They should be asked to use one finger to point to the area of maximal pain or discomfort and press that area with their thumb. Localised tenderness along distribution of deep venous be noted. Pitting/non-pitting oedema should also be documented by asking the patient to press the front of the leg above the ankle for 30 s. The patient should be asked if they can feel a cordlike structure in the leg suggestive of thrombosed superficial veins.


The patient’s gait should be evaluated for any limping or discomfort. Pain of the calf on sudden dorsiflexion of the ankle joint should be noted. The range of motion testing should be tested actively (asking patients to move their joints) or passively (asking family members to move the joints) of hip, knee and ankle. Finally, the patient should be asked to measure their leg circumference from specific points (measured 10 cm below tibial tuberosity) and any difference in measurement between limbs conveyed to the examiner.


The patients with a positive history and physical examination should be assessed with the Wells score to determine the pretest probability of DVT.25–27 This score reduces the need for serial ultrasound testing for the diagnosis of DVT. Current NICE guideline NG158 recommends a two-tier score of whether DVT is unlikely (≤1 point) or DVT is likely (≥2 points). Patients with low probability should be tested with D-dimer and if positive, venous duplex ultrasonography (VDU) should be performed (figure 1—flow chart). The D-dimer levels are uniformly elevated in patients with COVID-19. So, it is difficult to predict the level of significance in concomitant COVID-19 and DVT pathologies. Anticoagulation is strongly recommended in patients with positive VDU. For negative results, repeat VDU can be considered for re-evaluation in cases with high suspicion of DVT.

Figure 1

Flow chart for virtual deep venous thrombosis (DVT) risk assessment. COPD, chronic obstructive pulmonary disease; RR, respiratory rate; SOB, shortness of breath; USS, ultrasound scan.



Authors acknowledge the proposed pathway is not a validated route of assessment yet. Validation will require comparing TM approach with the traditional approach that involves physical examination by a clinician and investigation of the patient. There will be a need to ensure quality assurance and improvement of this model. However, virtual DVT assessment examination model is a novel concept put forward by the authors. The model will surely be developed further to become a consistent form of assessment as the process is refined; regular audits are undertaken for quality assurance and monitor continual improvement. Patient perception and acceptance of virtual DVT assessment with TM will need to be considered which can be evaluated by further research studies.


COVID-19 has restricted traditional ‘face-to-face’ assessments and attendances at primary care and in-hospital outpatient departments. Innovative ways need to be found to facilitate early diagnosis and management of a patient with suspected DVT as with other significant medical conditions. This is particularly relevant during the current pandemic since COVID-19 is acknowledged as a pro-coagulant condition. Virtual assessment pathway is not a replacement for conventional ‘face-to-face’ evaluation, but we believe the template can be explored and refined to act as a blueprint for future applications even when the COVID-19 pandemic has stabilised.

Main messages

  • Social distancing and infection prevention guidelines due COVID-19 have necessitated the need to discover alternatives to conventional ‘face-to-face’ DVT risk assessment in the primary care and community settings.

  • Virtual DVT risk assessment pathway may allow initial remote assessment for DVT and help formulate a management plan.

  • Virtual DVT risk assessment will thus support initial evaluation in the community and prompt referral to secondary care following decision-making probability score.

Current research questions

  • How to validate such a virtual DVT risk assessment pathway?

  • Patient-directed examination compared with clinical evaluation—a comparison to assess variability.

  • How do we assess patient acceptability of telemedicine to diagnose DVT? Will they feel confident and accept it?

What is already known on the subject

  • DVT of the lower limb can lead to non-fatal or fatal PE.

  • Diagnosis of DVT depends upon ac combination of history, assessment of clinical risk and investigations.

  • Antithrombotic prophylaxis is safe and effective.



  • Contributors KPI involved in conceptualisation and writing the original draft of manuscript, literature search, planning, conduct and editing. VJ, MS, ZH involved in literature search, review and editing. All authors have read and agreed to the final draft before submission.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No data are available.