Exploration into lipid management and persistent risk in patients hospitalised for acute coronary syndrome in Japan (EXPLORE-J): Protocol for a prospective observational study

Introduction The present study is the largest registry study ever conducted in Japan exploring the prevalence of familial hypercholesterolaemia (FH) among patients with acute coronary syndrome (ACS). Our study aims to (1) evaluate the status of lipid management and the subsequent risk of major cardiovascular events following hospitalisation of Japanese patients with ACS in real-world clinical practice; (2) determine the proportion of Japanese patients with ACS who achieve the lipid management goal and have a reduction of event risks with strict lipid management (low-density lipoprotein-cholesterol <1.81 mmol/L); (3) determine the prevalence of FH and (4) investigate the clinical significance of proprotein convertase subtilisin kexin 9 (PCSK9) level. Methods and analysis We will conduct a multicentre, prospective, observational study of approximately 2000 Japanese patients with ACS with/without FH hospitalised between April 2015 and August 2016. The primary end point is the incidence of major adverse cardiovascular events (MACEs) after initial hospitalisation. The secondary end points are (1) MACE developed from visit 1 to visit 2 (day 30); (2) MACE developed from visit 2 (day 30) to visit 5 (day 730); (3) treatment rate by lipid-lowering therapies (any statin or intensive, PCSK9 inhibitor, fibrates and ezetimibe); (4) incidence of events by the addition of the following outcomes to the primary end point: coronary revascularisation due to myocardial ischaemia, revascularisation other than coronary artery, inpatient treatment for occurrence or exacerbation of heart failure, transient ischaemic attack, acute arterial occlusion, central retinal artery occlusion and other adverse events prolonging or requiring hospitalisation and (5) proportion of subjects achieving target lipid levels. Ethics and dissemination The study protocol was submitted to the ethical review committee of each participating centre for approval. Participation in the study is voluntary and anonymous. The study findings will be disseminated in international peer-reviewed journals and presented at relevant conferences.