Oxidized LDL, Lipoprotein (a), and Other Emergent Risk Factors in Acute Myocardial Infarction (FORTIAM Study)

Introduction and objectivesTo determine the prevalence of acute myocardial infarction (AMI) without classical risk factors, and to ascertain whether affected patients exhibit a higher prevalence of emergent risk factors and whether the presence of specific emergent risk factors influence prognosis at 6 months.MethodsThe FORTIAM (Factores Ocultos de Riesgo Tras un Infarto Agudo de Miocardio) study is a multicenter cohort study that includes 1371 AMI patients who were admitted within 24 hours of symptom onset. Strict definitions were used for classical risk factors and the concentrations of the following markers were determined: lipoprotein (a) [Lp(a)], oxidized low-density lipoprotein (oxLDL), high-sensitivity C-reactive protein, fibrinogen, homocysteine, and antibody to Chlamydia. The endpoints observed during the 6-month follow-up were death, angina, and re-infarction.ResultsThe prevalence of AMI without classical risk factors was 8.0%. The absence of classical risk factors did not affect the 6-month prognosis. The only emergent risk factors independently associated with a poorer prognosis were the Lp(a) and oxLDL concentrations. Cutpoints were determined using smoothing splines: 60 mg/dL for Lp(a) and 74 U/L for oxLDL. The associated hazard ratios, adjusted for age, sex, and classical risk factors, were 1.40 (95% confidence interval, 1.06-1.84) and 1.48 (95% confidence interval, 1.06-2.06), respectively.ConclusionsThe proportion of AMI patients without classical risk factors was low and their prognosis was similar to that in other AMI patients. Both oxLDL and Lp(a) concentrations were independently associated with a poorer 6-month prognosis, irrespective of the presence of classical risk factors.

Introducción y objetivosDeterminar la prevalencia de pacientes que sufren un infarto agudo de miocardio (IAM) sin factores de riesgo (FR) clásicos, si presentan una mayor prevalencia de FR emergentes y si algún FR emergente modifica el pronóstico a los 6 meses.MétodosFORTIAM (Factores Ocultos de Riesgo Tras un Infarto Agudo de Miocardio) es un estudio multicéntrico de cohortes de 1.371 pacientes que sufrieron un IAM e ingresaron en las primeras 24 h. Se utilizaron definiciones estrictas para los FR clásicos y se determinaron: lipoproteína (a) [Lp(a)], lipoproteína de baja densidad oxidada (LDLox), proteína C reactiva ultrasensible, fibrinógeno, homocisteína y anticuerpos anticlamidia. Los acontecimientos de interés a los 6 meses fueron: muerte, angina o reIAM.ResultadosLa prevalencia de pacientes con IAM sin FR clásicos fue del 8%. La ausencia de FR clásicos no afectó al pronóstico a los 6 meses. Lp(a) y LDLox fueron los únicos FR emergentes que de forma independiente se asociaron a un peor pronóstico. Puntos de corte (suavización con splines): 60 mg/dl para Lp(a) y 74 U/l para LDLox. La hazard ratio ajustada por edad, sexo y FR clásicos, 1,40 (intervalo de confianza [IC] del 95%, 1,06- 1,84) y 1,48 (IC del 95%, 1,06-2,06), respectivamente.ConclusionesLa proporción de pacientes con un IAM sin FR clásicos es baja y su pronóstico es similar al resto de pacientes con IAM. LDLox y Lp(a) se asociaron a un peor pronóstico a los 6 meses de forma independientemente de los FR clásicos.