DVT can be clinically very difficult to diagnose but early recognition and appropriate treatment can improve clinical outcomes.
In 2009 South West Essex community services, now part of North East London Foundation Trust, established a DVT service based at Brentwood Community Hospital aimed at improving DVT diagnostic services for nine GP practices in the Brentwood area, serving a population of 74,000 people in south west Essex.
Patients presenting to their GP with symptoms suggestive of a DVT are referred via a phone call to the service, with the patients’ details then sent electronically or by fax. The referral process has been made as simple and streamlined as possible in order to reduce the administration burden on referring GPs and their practices. The centre is able to accept the referral via the phone call and the patient is sent directly to the centre to be seen as soon as they arrive. No appointment system is in operation, reducing patients’ waiting time once they are referred.
Patients are initially assessed with a Wells score and those with a low probability score for DVT are then offered a D-dimer test using the cobas h232 point of care system from Roche Diagnostics. This quantitative diagnostic system needs no subjective interpretation and, in association with a low probability Wells score, allows the nurse to safely rule out DVT in primary care, ensuring only patients at higher risk are referred for further imaging tests. The service also benefits from an on-site Doppler scanner enabling fast and cost-effective diagnosis.
The Brentwood service is entirely nurse-led, with the exception of the clinical lead senior consultant haematologist Dr Andrew Hughes, which means while the centre operates efficiently, atypical presentations can be assessed and managed quickly on-site.
D-dimer is a specific fragment of cross-linked fibrin that circulates in the blood stream for several days following a thrombotic event, such as DVT. It is produced naturally as part of the normal clotting process but can also be found in increased quantities in the blood in abnormal clotting processes, and so the presence of D-dimer can indicate the occurrence of unwanted thrombotic events. The use of D-dimer with a clinical decision rule such as the Wells score can reduce treatment costs by decreasing the need for costly imaging techniques for all patients presenting with suspected DVT.
Patients with a low probability Wells score and negative D-dimer can be discharged, with careful safety-net instructions to seek further medical advice in the case of persisting or worsening symptoms, or general patient concern.
Results of the service
The DVT service sees on average 250 patients per year. With each acute DVT presentation costing approximately £500 per patient if referred to secondary care, these patients would have represented a total cost of £125,000 a year. However, all patients can now be assessed and managed in primary care with an approximate annual saving of £60,000.
Savings are also made in time, as well as in costs. Following a suspected DVT referral to BCH it takes approximately 30 to 60 minutes f or a patient to be seen and assessed, including carrying out the D-dimer test, which takes eight minutes to give a result.
The majority of patients referred to the DVT pathway by GPs do not have DVT, but point of care testing and diagnosis using the D-dimer test enables rapid identification and treatment of appropriate patients at low or higher risk of DVT, enabling appropriate further management. Patients also report that being able to have their condition assessed more rapidly and in a primary care setting is much less stressful for them.
Dr Hughes commented: “This service is highly cost-effective. The DVT service is better for GPs and patients clinically and practically, yet also offers a cost-saving to service commissioners. Efficiencies like this are essential for helping the NHS to deliver better services more efficiently, now and in the future.”
Benefits of the Service
- Point of Care D-dimer testing allows patients with suspected DVTs to be safely assessed in a primary care setting
- A negative D-dimer in association with a low probability Wells score helps to rule out thromboembolic events
- The use of POC D-dimer testing with a Wells score can decrease the number of patients who require referral to secondary care for a Doppler scan down by up to 50 per cent
- A primary care-based initial assessment service is easy to access for both GPs and patients with clear benefits for both
- By decreasing the number of secondary care referrals significant cost savings can be made.
The Wells Score - Deep Vein Thrombosis
|Active cancer (patient receiving treatment for cancer within the previous 6 months or currently receiving palliative treatment)||1|
|Paralysis, paresis, or recent plaster immobilisation of the lower extremities||1|
|Recently bedridden for 3 days or more, or major surgery within the previous 12 weeks requiring general or regional anaesthesia||1|
|Localised tenderness along the distribution of the deep venous system||1|
|Entire leg swollen||1|
|Calf swelling by more than 3 cm compared with the asymptomatic leg (measured 10 cm below the tibial tuberosity)||1|
|Pitting oedema confined to the symptomatic leg||1|
|Collateral superficial veins (non-varicose)||1|
|Alternative diagnosis at least as likely as DVT||-2|
Score: 0 = Low probability, 1-2 = Intermediate probability, >3 = High probability