The prescription of best medical therapy following infrainguinal bypass grafting in Australia and New Zealand: a multicentre Australasian audit

Background: The benefits of best medical therapy (BMT) for secondary prevention of cardiovascular events in patients with peripheral arterial disease are well established. Guidelines recommend prescription of BMT should consist of anti-platelet, statins and angiotensin-converting enzyme inhibitor or angiotensin receptor blocking therapy, with evidence this regimen reduces cardiovascular mortality following vascular surgery and improves vascular bypass graft patency. This multicentre study examines the BMT prescription on discharge after infrainguinal bypass (IIB) in Australia and New Zealand (ANZ). Primary outcome measure was discharge prescription of three BMT pharmacological agents, defined for study purposes as an anti-platelet/anti-coagulant, a lipid-lowering agent, and an anti-hypertensive medication if hypertension was diagnosed.

Methods: This study retrospectively examined discharge prescriptions and summaries of all patients discharged following IIB in five ANZ hospitals, between January 2015 and April 2018.

Results: A total of 688 admissions for IIB were included (76.9% male; mean age 67.8 ± 12.0). A total of 72.4% of procedures were for chronic limb ischaemia, compared to acute limb ischaemia (12.6%), and aneurysmal disease (15%). The primary outcome of adherence with complete BMT prescription occurred in 66.9% of admissions. Anti-thrombotic agents were most frequently prescribed (96.4%), followed by anti-lipidaemic agents (82.1%). Of the patients with documented hypertension, 43.8% were not prescribed an angiotensin-converting enzyme inhibitor/angiotensin receptor blocking, while 19.2% were discharged without any anti-hypertensive medications.

Conclusion: Almost one third of patients were not prescribed complete BMT following IIB. There is potential to improve the outcomes after IIB in ANZ through a focus on risk-factor control and BMT prescription.