Role of LipoprotEin(a) in CardiovascuLar Diseases and Premature Acute Coronary Syndromes - (RELACS) Study

Although acute myocardial infarction (AMI) is more common in the elderly, its incidence in young patients is increasing. The exact pathogenetic mechanism of AMI in young patients remains largely unknown and involves the interaction of multiple genetic and environmental factors related to atherothrombosis. The cardiovascular risk profile and coronary artery disease burden differ between young and elderly patients with AMI. Generally, compared with elderly patients, patients with premature AMI have a lower atherosclerotic burden, as well as a lower incidence of hypertension and diabetes mellitus. Still, they more frequently have a hypercoagulable state with high fibrinogen and D-dimer levels and genetic disorders of lipid metabolism (1) with elevated triglyceride and lipoprotein (a) [Lp(a)] levels (2).

Lp(a) is a lipoprotein with pro-atherogenic, pro-thrombotic and pro-inflammatory properties (3). Lp(a) consists of a lipid component with apoB100 and a protein component represented by Apo(a)(3,4). Apo(a) shows substantial structural homology with plasminogen, suggesting that the former protein can inhibit the binding of plasminogen to its receptor, thereby interfering with fibrinolysis and inducing a prothrombotic state. Several studies have shown that increased plasma levels of Lp(a) are associated with an increased risk of coronary artery disease (5), peripheral arteriopathy (6), cerebrovascular disease (7), abdominal aortic aneurysm, aortic valve stenosis and calcification (8), and venous thromboembolism (9). In addition, elevated Lp(a) levels are associated with an increased risk of major cardiac adverse events (10). In contrast, a recent study that included approximately 1,500 patients with a history of acute coronary syndrome (ACS) at least six months after enrollment showed that Lp(a) appears to be an independent risk factor for ACS in individuals <45 years young (especially in the presence of LDL-C cholesterol levels >70 mg/dL) (11). This association is of lesser magnitude (but still preserved) between 45-60 years of age and becomes nonsignificant after 60 years of age. Despite increasing evidence in the literature, Lp(a) determination is infrequently performed in patients with early-onset ACS referred to Cardiology Departments and Outpatient Departments. Therefore, hyper-Lp(a) remains largely under-diagnosed even in patients at high or very high cardiovascular risk.

Therefore, the purpose of our study is to evaluate the correlation between Lp(a) and recurrence of cardiovascular events such as cardiovascular mortality, recurrence of anginal symptoms, new revascularizations (PCI/CABG), or new hospitalizations at 1-year follow-up in patients with premature ACS, which includes myocardial infarction with ST-segment elevation (STEMI), acute myocardial infarction without ST-segment elevation (NSTEMI) and unstable angina (UA).