Dr Barry Kevane
Consultant Haematologist, Mater Misericordiae University Hospital & Ireland East Hospital Group
Hospital-acquired venous thromboembolism (HA-VTE) is the leading cause of preventable hospital deaths.
Venous thromboembolism: Acute and chronic morbidity & mortality
Venous thromboembolism (VTE), which comprises primarily of pulmonary embolism (PE) and deep vein thrombosis (DVT), has an annual incidence of approximately one in 1,000.
VTE is recognised as being a leading cause of cardiovascular mortality worldwide. Among survivors, a substantial burden of chronic morbidity has been reported.
Well-known chronic complications of VTE include a potentially life-threatening pulmonary vascular disease called chronic thromboembolic pulmonary hypertension, and post-thrombotic syndrome; a disorder characterised by chronic pain, swelling and ulceration of limbs affected by deep vein thrombosis.
Recent data pertaining to a range of other newly described ‘post-PE’ syndromes has also been reported, suggesting that a substantial burden of chronic morbidity associated with this condition exists, which has likely been under-appreciated until recently.
This chronic morbidity associated with VTE is a major contributor to healthcare resource utilisation globally as well as a major negative influence on patient quality of life.
A number of risk factors have been identified as being associated with an increased risk of VTE.
Major surgery, active cancer, prolonged immobilisation with medical illness and traumatic injury with limb fracture are amongst the most clinically significant VTE risk factors encountered in clinical practice. Other risk factors include pregnancy, oestrogen therapy and long-haul travel.
However, while VTE may arise for different reasons in different people, the majority of all these VTE events occur during admission to hospital.
This is likely because multiple transient VTE risk factors frequently arise among hospital in-patients (such as immobility, acute infection/inflammation, major surgery etc.).
Crucially, while VTE is common in hospitals, high-quality data has consistently demonstrated that the majority of these VTE events are preventable, provided appropriate steps to reduce VTE risk are taken.
Effective VTE prevention strategies consist primarily of the use of validated clinical risk assessment tools (to identify high-risk patients) followed by the appropriate use of pharmacological thromboprophylaxis with anticoagulant medicines to reduce the chance of blood clotting during these high-risk periods.
As most instances of HA-VTE are preventable, deaths associated with HA-VTE are also likely to be preventable in many cases.
The implementation of standardised VTE prevention strategies in other countries, including the UK, has been proven to reduce VTE-related mortality in hospitals.
Recently, the HSE has made a concerted effort to address the major risk posed by HA-VTE in Irish hospitals.
Guidelines for prevention of HA-VTE in Ireland have been published and a HA-VTE national key performance indicator has been introduced for all Irish hospitals to drive VTE quality improvement initiatives.
VTE prevention in the era of COVID-19
COVID-19 is posing challenges across our healthcare system. At an early stage of the pandemic, derangements of blood coagulation were identified as being hallmarks of this infection and as being indicators of poor outcome.
Moreover, very high rates of thrombosis have been reported, which are associated with COVID-19, and appear to occur despite standard VTE prevention practices.
Clinical trials to determine the optimal prevention strategy are awaited but, in the interim, adherence to existing evidence-based guidelines for VTE prevention and maintaining a high level of vigilance in our approach to VTE prevention is vital.