Cardiothoracic ratio from postero-anterior chest radiographs: A simple, reproducible and independent marker of disease severity and outcome in adults with congenital heart disease

Objective The wide spectrum of intracardiac anatomy and reparative surgery available for adults with congenital heart disease (ACHD) makes uniform measurement of cardiac size and disease severity challenging. The aim of this study was to assess the prognostic potential of cardiothoracic ratio, a simple marker of cardiomegaly, in a large cohort of ACHD. Patients and setting Chest radiographs from 3033 ACHD patients attending our institution between 1998 and 2007 and 113 normal controls of similar age were analyzed blindly. Design Cardiothoracic ratio derived from plain postero-anterior chest radiographs, was compared between ACHD patients and controls, different diagnostic subgroups and different functional classes. Relationship between cardiothoracic ratio and survival was assessed using Cox regression. Results Average cardiothoracic ratio in ACHD was 52.0±7.6% (over 50% in 56.4%), significantly higher in all ACHD diagnostic subgroups compared to controls (42.3±4.0%, p<0.0001) and highest in the “complex” cardiac anatomy, Ebstein's anomaly and Eisenmenger subgroups. Cardiothoracic ratio related to functional class, but was high even in asymptomatic patients. During a median follow-up of 4.2years, 164 patients died. Patients with a cardiothoracic ratio >55% had an 8-fold increased risk of death compared to those in the lowest tertile (<48%). Even patients with mildly increased cardiothoracic ratio (48–55%) had an adjusted 3.6-fold increased mortality compared to the lowest tertile. Conclusions Cardiothoracic ratio derived from postero-anterior chest radiographs is a simple, and reproducible marker, which relates to functional class and predicts independently mortality risk in ACHD patients.