Comprehensive Venous Thromboembolism Prevention Programme Incorporating Mandatory Electronic Risk Assessment Reduces the Incidence of Hospital-Associated Thrombosis: A Single Centre Experience
Authors: Roberts Lara N , Porter Gayle , Patel Raj K , Bonner Lynda , Arya Roopen 
Published: October 2019

Abstract
Abstract 363
The national Venous Thromboembolism (VTE) Prevention Programme in England incorporates standardised guidance on risk assessment (RA) and thromboprophylaxis (TP) with a requirement for root cause analysis of all episodes of hospital associated thrombosis (HAT), defined as any VTE occurring whilst an inpatient or within 90 days of discharge. We previously reported findings of root cause analysis for HAT from 2010. We present updated findings from combined census of VTE RA and the root cause analysis programme at King's College Hospital, London over a 24 month period. A principal change in VTE RA process was the phased introduction of prompted electronic RA in 2011. Census data collection of RA identified a significantly higher median monthly RA rate in 2011 of 93.9% (IQR 92.3 – 94.5) compared to 85.8% (IQR 72.0–90.4; P=0.001) in 2010. The root cause analysis programme for HAT identified 192 episodes in 2011 compared to 236 events in 2010. The median number of events per month was significantly lower at 1.2 per 1000 admissions (IQR 0.8 to 1.4) in 2011 compared to 1.5 per 1000 admissions (IQR 1.3 – 1.8; P=0.023) in 2010. There was no significant difference in type of admission preceding HAT between 2010 and 2011 (medical 55.5% vs 47.4%, surgical 42.4% vs 49.5% and obstetric 2.1% vs 3.1% respectively). The proportion of HAT presenting as PE was lower in 2011 (36.7%) compared to 2010 (46.7%, P=0.07). The proportion of fatal PE was non-significantly lower in 2011 at 6.2% (n=12) compared to 2010 (7.3%, n=17). There was no significant difference in 90 day mortality between 2010 and 2011 (21.2% vs 19.3%). Root cause analysis was completed for 65.3% and 89.0% of HATs in 2010 and 2011 respectively. Of investigated episodes, RA was completed for 85.4% in 2011 compared to 43.9% (P<0.001) in 2010. RA rates in HAT were significantly lower than hospital wide rates of RA in 2010 (P=0.008) and 2011 (P=0.002). There was no difference in VTE risk between those who developed HAT in 2010 compared to 2011 (high VTE risk 93.3% vs 96.5% with concomitant high bleeding risk in 36.7% and 36.8% respectively). However, risk profile of those with HAT was significantly different to that identified in hospital wide TP audit of electronic patient records, where high VTE risk was identified in 86.1% (P<0.001) with concomitant bleeding risk in 22.5% (P<0.001). Of those with high VTE and low bleeding risk, significantly more patients with HAT received anticoagulant prophylaxis in 2011 (91.0%) compared to 2010 (72.1%, P=0.001). Of those with both high VTE and bleeding risk, there was no difference in the use of mechanical thromboprophylaxis between 2010 and 2011. The profile of underlying root cause was significantly different in 2011 with less HAT attributable to inadequate thromboprophylaxis (21.1% vs 30.7%, P=0.058), more events associated with a contraindication to anticoagulant prophylaxis (27.5% vs 18.1%, P=0.057) and significantly more events due to TP failure (40.9% vs 28.3%, P=0.024) compared to 2010. Electronic solutions to support VTE prevention combined with dedicated VTE training led to improved overall RA with a significant reduction in HAT of almost 20% over a two year period. A comprehensive VTE prevention programme significantly reduces preventable patient harm.

Disclosures:
No relevant conflicts of interest to declare.