Aspirin for Primary Prevention of Cardiovascular Events in Patients with Elevated Lipoprotein(a): the Multi-Ethnic Study of Atherosclerosis

Introduction: There is a lack of effective therapies for reducing risk in people with elevated Lp(a), especially for primary prevention. We aimed to evaluate the association between aspirin use and cardiovascular events (CVD) in people with elevated Lp(a). Methods: We performed a prospective cohort study using data from participants from the Multi-Ethnic Study of Atherosclerosis (MESA) who were free of baseline cardiovascular disease. We matched aspirin users and non-users using a propensity score based on CVD risk factors. We then evaluated the association between aspirin use and coronary heart disease (CHD) events (CHD death, non-fatal myocardial infarction) stratified by baseline Lp(a) level (above and below 50 mg/dL) using Cox proportional hazards models with adjustment for CVD risk factors. Results: Our study cohort included 6,632 participants, including 1,138 (20%) with Lp(a) >50 mg/dL and 1,592 (24%) with baseline aspirin use. Participants with elevated Lp(a) had a higher burden of CVD risk factors, with a trend toward greater aspirin use (25.7% vs 23.6%, p=0.10) and significantly higher CHD events (9.0% vs 7.3%, p=0.03). After propensity matching, aspirin was associated with a significant reduction in CHD events among those with elevated Lp(a) (HR 0.54, 95% CI 0.32-0.94, p=0.03). Those with Lp(a) >50 mg/dL with aspirin use had similar freedom from CHD as those with Lp(a) ≤50 mg/dL regardless of aspirin use ( Figure ). Conclusions: Aspirin use was associated with a significant reduction in CHD events in participants with elevated Lp(a) without baseline CVD. These results are hypothesis generating and require confirmation in studies with randomization of aspirin use.