Physiological differences between various types of Eisenmenger syndrome and relation to outcome

Eisenmenger syndrome (ES) is the most advanced form of pulmonary arterial hypertension (PAH) related to congenital heart disease. Several studies have suggested that the presence and location of the shunt defines the natural history of these patients by influencing right ventricular adaptation to PAH. We aimed to echocardiographically assess differences in cardiac physiology and outcome between various types of ES.

In this longitudinal cohort study, 191 patients with ES and non-complex congenital heart disease were recruited, 36 with pre-tricuspid and 155 with post-tricuspid shunts. Patients with pre-tricuspid shunts were older, had higher BNP concentrations and lower exercise tolerance compared to patients with post-tricuspid shunts. Right ventricular (RV) function was impaired in patients with atrial septal defects, with larger right ventricles, impaired systolic function and adaptation. The left ventricular eccentricity index was significantly higher in pre-tricuspid defects. Within post-tricuspid shunts, patients with atrio-ventricular septal defects had better right ventricular function compared to ventricular septal defects, while in those with a patent ductus arteriosus this was worse. There was a trend towards lower mortality in patients with post versus pre-tricuspid shunts, which was significant for patients above the age of 48 years.

The presence of a post-tricuspid shunt appears to carry physiological and possibly prognostic benefits in ES compared to patients with pre-tricuspid shunts. This should be borne in mind when management decisions and advanced therapies are considered.