INTRODUCING EXTENDED VENOUS THROMBOEMBOLISM PROPHYLAXIS FOR HIGH-RISK VASCULAR PATIENTS UNDERGOING LOWER LIMB AMPUTATION - A QUALITY IMPROVEMENT PROJECT.

Editor,

Venous Thrombo-Embolism (VTE) is an established cause of morbidity and mortality amongst vascular surgery patients undergoing lower limb amputation1,2. All-cause mortality rates amongst this patient group are already substantial3, thus VTE risk reduction may improve outcomes. However, best practice regarding post-operative VTE prophylaxis is unclear4,5.

National Institute of Clinical Excellence guidelines suggest that vascular surgery patients should receive low-molecular-weight heparin until mobility is no longer significantly reduced 1. However, for many amputees, the reduction in mobility from baseline is permanent, and the optimum duration of VTE prophylaxis is unclear.

The aims of this Quality Improvement Project (QIP) were: -

to establish baseline practice within Northern Ireland’s regional Vascular Surgery Unit regarding VTE risk-assessment and prophylaxis upon discharge

introduction of a novel VTE risk-assessment proforma

completion of two Plan-Do-Study-Act (PDSA) cycles to assess use of the proforma.

Prior to this QIP, VTE risk-assessment would be undertaken amongst all vascular patients upon admission, and prophylactic-dose enoxaparin prescribed during the inpatient stay (if indicated). However, there was typically no formal assessment of ongoing VTE risk upon discharge.

The VTE risk-assessment proforma was devised in conjunction with the local Haematology department and approved by the regional pharmacy group. The proforma was designed to facilitate assessment of the risk of VTE development versus the risk of bleeding should anticoagulation be prescribed. Where indicated, prophylactic-dose enoxaparin for thirty days post-operatively was recommended.

Information regarding VTE risk-assessment and prophylaxis upon discharge amongst patients undergoing lower limb amputation was obtained via review of inpatient records and electronic discharge prescriptions. Assessment of baseline practice was conducted throughout August - October 2016. Two subsequent PDSA cycles were conducted at one week and at two months following formal introduction of the proforma (April 2017). Interventions were made in the form of weekly educational seminars for junior doctors and empowerment of the ward pharmacist to encourage proforma use.

Results of the study are demonstrated in . At baseline, none of the patients underwent VTE risk-assessment upon discharge and none received new anticoagulation. One week following proforma introduction, 67% of patients underwent VTE risk-assessment +/− enoxaparin prescription. Two months following proforma introduction, compliance had risen to 80%.

Barriers to using the risk-assessment proforma include lack of staff awareness, which may reflect the rotation- and shift-based working patterns of junior doctors. Due to the single-centre nature of this study with small patient numbers, it has not been possible to determine statistical significance of our results.

In summary, patients undergoing lower limb amputation are generally at high risk for developing VTE due to pre-operative co-morbidities and post-operative immobility. With this QIP, we have introduced a novel VTE risk-assessment proforma and demonstrated acceptable and improving compliance levels at one-week and two-month intervals. We anticipate that with increased familiarity of staff with the proforma, all patients will be risk-assessed upon discharge and will receive VTE prophylaxis if indicated. Further work should assess ongoing compliance with the proforma, and explore the impact of extended VTE prophylaxis on morbidity and mortality amongst vascular surgery patients.

Table 1

Numbers of patients for whom Venous Thrombo-Embolism (VTE) risk-assessment was undertaken upon discharge, and VTE prophylaxis (enoxaparin for 30 days from date of lower limb amputation) prescribed where indicated, is shown.

	Total number of patients undergoing lower limb amputation	Number considered at risk for post-operative VTE	Number already receiving anticoagulation for pre-operative factors	Number receiving risk assessment +/− extended VTE prophylaxis upon discharge	Number managed in accordance with novel proforma
Baseline	17	15	3	0	3/15 (20%)
Cycle I	6	6	0	4	4/6 (67%)
Cycle II	20	20	4	16	16/20 (80%)