Preventing Postpartum Venous Thromboembolism: Exploring the Impact of a Systematic Approach to Individualised VTE Prevention

Pregnancy-associated VTE (PA-VTE) is a leading cause of maternal morbidity and mortality in the developed world.1 However, in many cases, PA-VTE is preventable using pharmacological thromboprophylaxis. In 2014, a comprehensive VTE prevention protocol was introduced at the Rotunda Hospital to streamline the identification of women at risk of VTE and promote use of risk-appropriate thromboprophylaxis in line with local guidelines. The VTE prevention protocol centred on two components; a postnatal VTE electronic risk assessment tool called ‘Thrombocalc’, and a comprehensive clinical guideline on the prevention of PA-VTE.

The aim of this thesis was to explore the need for, and potential impact of, a comprehensive, systematic postpartum VTE prevention protocol. Three distinct studies were carried out to achieve this.

First, in a cross-sectional study of over 21,000 postpartum women from an Irish maternity hospital, a high prevalence of VTE risk factors was observed, which in some cases was higher than other European populations. VTE risk was noted to be highly individualised and dynamic, supporting the need for systematic VTE risk assessment and an individualised approach to VTE prevention.

Then, Thrombocalc’s novel risk score was validated using a cohort of over 300,000 pregnancies recorded in the Danish Medical Birth Register. At the risk threshold used in the Rotunda Hospital, the VTE risk score had a sensitivity of 67% and a specificity of 62%. Thrombocalc’s risk score demonstrated higher sensitivity when compared with previous and current risk assessment tools from the Royal College of Obstetricians and Gynaecologists in the UK.

Finally, using a before and after study design, implementation of the VTE prevention protocol was shown to increased compliance with documented VTE risk assessment (2% to 98%, p < 0.001), increase prescription (67% to 91%, OR 5.05, p <0.001) and timely administration (42% to 66%, OR 2.03, p = 0.05) of risk-appropriate pharmacological thromboprophylaxis in a standalone maternity hospital in Ireland.

In conclusion, this body of research demonstrates that a comprehensive VTE prevention protocol enables systematic and individualised assessment of VTE risk and promotes the implementation risk-appropriate thromboprophylaxis in line with local guidelines. It is hypothesised that such improvements may ultimately contribute to effective prevention of postpartum VTE.