AUTHOR=González-Pacheco Héctor , Ortega-Hernandez Jorge Arturo , Meza-López Jesús Ángel , Soliz-Uriona Luis Alejandro , Manzur-Sandoval Daniel , Gopar-Nieto Rodrigo , Araiza-Garaygordobil Diego , Sierra-Lara Daniel , Arias-Sánchez Eduardo , Sandoval Juan Pablo , Altamirano-Castillo Alfredo , Mendoza-García Salvador , Arzate-Ramírez Arturo , Baranda-Tovar Francisco Martin , Martinez Humberto , Montañez-Orozco Álvaro , Baeza-Herrera Luis Augusto , Sierra-González De Cossio Alejandro , Arias-Mendoza Alexandra 

TITLE=Analysis of immortal-time effect in post-infarction ventricular septal defect

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2023.1270608

DOI=10.3389/fcvm.2023.1270608

ISSN=2297-055X

ABSTRACT=Introduction: Time-fixed analyses have traditionally been utilized to examine outcomes in post-infarction ventricular septal defect (VSD). The aims of this study were to: 1) analyze the relationship between VSD closure/non-closure and mortality; 2) assess the presence of immortal-time bias.In this retrospective cohort study, patients with ST-elevation myocardial infarction (STEMI) complicated by VSD. Time-fixed and time-dependent Cox regression methodologies were employed.The study included 80 patients: surgical closure (n=26), transcatheter closure (n=20), or conservative management alone (n=34). At presentation, patients without VSD closure exhibited high-risk clinical characteristics, had the shortest median time intervals from STEMI onset to VSD development (4.0, 4.0, and 2.0 days, respectively; P=0.03) and from STEMI symptom onset to hospital arrival (6.0, 5.0, and 0.8 days, respectively; P<0.0001). The median time from STEMI onset to closure was 22.0 days (P=0.14).In-hospital mortality rate was higher among patients who did not undergo defect closure (50%, 35%, and 88.2%, respectively; P<0.0001). Closure of the defect using a fixedtime method was associated with lower in-hospital mortality (HR=0.13, 95%CI 0.05-0.31, P<0.0001, and HR 0.13, 95%CI 0.04-0.36, P<0.0001, for surgery and transcatheter closure, respectively). However, when employing a time-varying method, this association was not observed (HR=0.95, 95%CI 0.45-1.98, P=0.90, and HR 0.88, 95%CI 0.41-1.87, P=0.74, for surgery and transcatheter closure, respectively). These findings suggest the presence of an immortal-time bias.This study highlights that using a fixed-time analytic approach in postinfarction VSD can result in immortal-time bias. Researchers should consider employing time-dependent methodologies.