Antiphospholipid Antibodies in Patients Hospitalized With Acute Coronary Syndrome at a Cardiovascular Center in Puerto Rico

Background: Antiphospholipid (aPL) antibodies have been associated with coronary artery disease, but their prevalence and clinical significance in acute coronary syndromes (ACS) vary across ethnic populations and remain understudied.Objective: This study aims to evaluate the frequency of single-time-point aPL positivity and its clinical associations in hospitalized patients with ACS in Puerto Rico.Methodology: A retrospective cross-sectional study of adults admitted with ACS to a tertiary cardiovascular center in Puerto Rico was conducted.ACS was defined as the presence of myocardial infarction or unstable angina.aPL testing included lupus anticoagulant (LA) and anticardiolipin (aCL) and anti-β2-glycoprotein I (anti-β2GPI) antibodies.Demographic characteristics, comorbidities, and in-hospital outcomes were compared between patients with positive and negative aPL testing using univariable and multivariable analyses.Results: Among 100 patients with ACS (mean age: 65.3 years; 55.0% male), 31% had at least one positive aPL test.LA was the most common positive test (26.0%),whereas aCL and anti-β2GPI antibodies were infrequent (≤3.0% for any isotype).Although aPL positivity was associated with longer hospitalization and more infections in univariable analyses, these associations were not retained after adjustment for age and sex.No differences were found in demographics, lifestyle behaviors, cardiovascular risk factors, comorbidities, or mortality.Conclusions: In this group of patients with ACS, aPL positivity was common, occurring in nearly one-third of patients, with LA accounting for the majority of positive results.The prevalence of aPL positivity in this ACS cohort exceeds that reported in prior studies and supports the need for confirmatory testing at ≥12 weeks to distinguish persistent from transient positivity and to further elucidate its prognostic significance.