Barriers to prescribing proprotein convertase subtilisin-kexin type 9 inhibitors after coronary revascularisation

Background Guidelines advocate for intensive lipid-lowering in patients with atherosclerotic cardiovascular disease (ASCVD). In May 2020, evolocumab, a proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitor, became government subsidised in Australia for patients with ASCVD requiring further low-density lipoprotein cholesterol (LDL-C) lowering. Aim To identify barriers to prescribing PCSK9 inhibitors in hospitalised patients with ASCVD. Methods A retrospective 3-month, single-site, observational analysis was conducted in consecutive patients undergoing percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery. Lipid-lowering therapy prescriptions, including PSCK9 inhibitors, were assessed using electronic medical records, compared against the Australian Pharmaceutical Benefits eligibility criteria, and barriers to PCSK9 inhibitor use identified. Results Of 331 patients, 244 (73.7%) underwent PCI and 87 (26.3%) underwent CABG surgery. A lipid profile during or within 8 weeks of admission was measured for 202 (82.8%) patients undergoing PCI and 59 (67.8%) undergoing CABG surgery. In patients taking high-intensity statins on admission (n = 109), LDL-C >= 1.4, >= 1.8 and >2.6mmol/L was seen in 64 (58.7%), 44 (40.4%) and 19 (17.4%) patients respectively. High-intensity statin prescribing at discharge was high (>80%); however, ezetimibe was initiated in zero patients with LDL-C >= 1.4 mmol/L. There was variable advice given by clinicians for LDL-C targets. No patients met the criteria for subsidised PSCK9 inhibitor therapy, largely due to lack of qualifying lipid levels following combined statin and ezetimibe therapy. Conclusion Prescribing of non-statin LDL-C-lowering therapies remains low in patients with ASCVD. Underprescribing of ezetimibe and suboptimal lipid testing rates are barriers to accessing subsidised PCSK9i therapy using current Australian eligibility criteria.